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PlatinumMetalsReview
www.platinummetalsreview.comE-ISSN 1471–0676
VOLUME 53 NUMBER 4 OCTOBER 2009
© Copyright 2009 Johnson Matthey PLC
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Platinum Metals Review is published by Johnson Matthey PLC, refiner and fabricator of the precious metals and sole marketing agent for the six platinumgroup metals produced by Anglo Platinum Limited, South Africa.
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Editor: David Jollie; Assistant Editor: Sara Coles; Editorial Assistant: Margery Ryan; Senior Information Scientist: Keith White
Platinum Metals Review, Johnson Matthey PLC, Orchard Road, Royston, Hertfordshire SG8 5HE, U.K.E-mail: [email protected]
E-ISSN 1471–0676
PLATINUM METALS REVIEWA Quarterly Survey of Research on the Platinum Metals and
of Developments in their Application in Industrywww.platinummetalsreview.com
VOL. 53 OCTOBER 2009 NO. 4
ContentsPlatinum Metals Review Highlights PGM Research 182
An editorial by David Jollie
A Highly Active Palladium(I) Dimer 183for Pharmaceutical Applications
By Thomas J. Colacot
Precious Palladium-Aluminium-Based Alloys 189with High Hardness and Workability
By Julien Brelle, Andreas Blatter and René Ziegenhagen
The 23rd Santa Fe Symposium on Jewelry 198Manufacturing Technology
A conference review by Christopher W. Corti
Novel Chiral Chemistries Japan 2009 203A conference review by David J. Ager
Melting the Platinum Group Metals 209By W. P. Griffith
PGM Highlights: Ruthenium Complexes 216for Dye Sensitised Solar Cells
By M. Ryan
“PEM Fuel Cell Electrocatalysts and Catalyst Layers: 219Fundamentals and Applications”
A book review by Gregory J. Offer
The Taylor Conference 2009 221A conference review by S. E. Golunski and A. P. E. York
Abstracts 226
New Patents 228
Indexes to Volume 53 230
Platinum Metals Rev., 2009, 53, (4), 182 182
Welcome to the October 2009 issue ofPlatinum Metals Review.
In this issue, we introduce a new occasionalseries of “PGM Highlights”, in which we pre-sent selected examples of activity in an area ofcurrent interest in platinum group metal (pgm)research. Here, we have chosen the area of pho-toconversion, in which ruthenium-based dyesplay a significant role for dye sensitised solarcells. This mini-review by Margery Ryan, of thePMR Editorial Team, highlights some of theinnovative work in the recent patent literature. Itis an extension of the patent abstracts that weselect for each issue, and aims to provide morein-depth coverage of the chosen area togetherwith some background, referenced to the widerscientific literature, to set the scene.
Additionally, this issue includes as usual ourannual Subject and Name Indexes, to appear inNovember. The Name Index lists the names ofall authors, reviewers and conference speakerswhose work has appeared in Volume 53. TheSubject Index gives detailed, fully cross-refer-enced entries for all of the pgm-containingcatalysts, alloys, compounds and complexesmentioned in this Volume, together with theprincipal topics by keyword. It serves to demon-strate the richness of pgm research that we havereported throughout 2009 and we hope that youwill find it a useful reference.
If you have any comments please contactme on: [email protected].
DAVID JOLLIE, Editor
Platinum Metals Review Highlights PGMResearch
DOI: 10.1595/147106709X477160
IntroductionThe palladium(I) dimer, di-μ-bromobis(tri-tert-
butylphosphine)dipalladium(I), [Pd(μ-Br)( tBu3P)]2,was synthesised and fully characterised by Mingos(1, 2). However, its potential as a unique C–C andC–N coupling catalyst (3) was first explored byHartwig (6). It has emerged as one of the bestthird-generation coupling catalysts for cross-cou-pling reactions, including C–heteroatom couplingand α-arylations. In this review, the physical andchemical characteristics of the Pd(I) dimer as a cat-alyst material are discussed from a practicalviewpoint, and up to date information on its appli-cations in coupling catalysis is provided.
Characteristics and HandlingThe Pd(I) dimer is a dark greenish-blue
crystalline material, which gives a single peak in the31P NMR spectrum at (δ) 87.0 ppm. The 1H NMRspectrum gives a peak at (δ) 1.33 ppm (singlet; onexpansion it appears as a distorted triplet) in deuter-ated benzene (1, 2). The compound decomposes in
chlorinated solvents, especially in deuterated chlo-roform. The X-ray crystal structure is reported inthe literature as a dimer with Pd–Pd bonding, stabilised by bromine atoms via bridge formation(1, 2). It can be handled in air as a solid for a shortperiod of time, allowing the user to place it into areactor in the absence of a solvent, degas and thencarry out catalysis under inert conditions. However,this compound is highly sensitive to air and mois-ture in the solution phase. It can also decompose inthe solid phase if not stored under strictly inert conditions. The solid state decomposition patternover time was monitored in our laboratory at 0, 48and 112 hours (Figure 1) (4). Its sensitivity towardsoxygen is well understood, and is based on the formation of an oxygen-inserted product with theelimination of hydrogen (Scheme I) (5). Figure 2shows the oxygen sensitivity of the Pd(I) dimer ona proton-decoupled 31P NMR spectrum recordedusing a solvent which was not degassed. The peakat 107 ppm indicates the presence of the oxygen-inserted decomposition product.
183Platinum Metals Rev., 2009, 53, (4), 183–188
A Highly Active Palladium(I) Dimer forPharmaceutical Applications[Pd(µ-Br)(tBu3P)]2 AS A PRACTICAL CROSS-COUPLING CATALYST
By Thomas J. ColacotJohnson Matthey, Catalysis and Chiral Technologies, West Deptford, New Jersey 08066, U.S.A.; E-mail: [email protected]
The Pd(I) dimer [Pd(μ-Br)( tBu3P)]2 is one of the best third-generation cross-coupling catalystsfor carbon–carbon and carbon–heteroatom coupling reactions. Information on itscharacterisation and handling are presented, including its decomposition mechanism in thepresence of oxygen. The catalytic activity of [Pd(μ-Br)( tBu3P)]2 is higher than either( tBu3P)Pd(0) or the in situ generated catalyst system based on Pd2(dba)3 with tBu3P. Examplesof suitable reactions for which the Pd(I) dimer offers superior performance are given.
DOI: 10.1595/147106709X472147
0 h 48 h 112 h
Fig. 1 The solid stateoxygen sensitivity of purePd(I) dimer, [Pd(μ-Br)( tBu3P)]2, withtime (4)
Applications in Coupling CatalysisThe high catalytic activity of the Pd(I) dimer
[Pd(μ-Br)(tBu3P)]2 is due to its ease of activation,presumably to a highly active, coordinatively unsat-urated and kinetically favoured ‘12-electron’catalyst species, (tBu3P)Pd(0) (Scheme II). Thisrenders the Pd(I) dimer more active than either theknown ‘14-electron Pd(0)’ catalyst, (tBu3P)2Pd(0),or the Pd(0) catalyst generated in situ by mixingPd2(dba)3 with two molar equivalents of tBu3P. Theapplications of the Pd(I) dimer in organic synthesisare described below.
Carbon–Heteroatom CouplingHartwig identified the potential of the Pd(I)
dimer as a highly active catalyst for C–N coupling
using aryl chlorides as substrates with variousamines at room temperature. A few examples areshown in Scheme III (6). Typically, aryl chloridecoupling requires higher temperatures and longerreaction times when using the in situ generatedPd(0) catalyst, or even the (tBu3P)2Pd(0) complex(7). Around the same time, Prashad and cowork-ers at Novartis reported an amination reactionusing [Pd(μ-Br)(tBu3P)]2 with challenging sub-strates such as hindered anilines (8). Scheme IVshows the coupling of N-cyclohexylaniline withbromobenzene, comparing the performance ofthe Pd(I) dimer with those of in situ generated cat-alysts derived from Pd(OAc)2 with tBu3P, BINAP,Xantphos or DPEphos. The performance of[Pd(μ-Br)(tBu3P)]2 is superior in each case.
Platinum Metals Rev., 2009, 53, (4) 184
180 140160 120 100 80 60 40 20 0 ppm
Fig. 2 The oxygensensitivity of Pd(I)dimer, [Pd(μ-Br)( tBu3P)]2, as observed in the 31P NMR (ppm)spectrum recordedusing non-degassedC6D6
P P
B r
P d
B r
P d O 2
- 2 H
O
P d
O
P d
C H 2
C H 2
P
B r P
B r
3 1 P N M R : 8 7 P P M 3 1 P N M R : 1 0 7 P P M
P d ( I ) d i m e r 31
P NMR: 107 ppm
–2H
P P
Br
Pd
Br
Pd P Pd
Highly active 12-electron species
Scheme I Theoxygen sensitivityof Pd(I) dimer,[Pd(μ-Br)( tBu3P)]2,with the formationof an inactive Pd-Ospecies (5)
Scheme II The activationof Pd(I) dimer to a 12-electron catalystspecies during couplingcatalysis
Pd(I) dimer
31P NMR: 87 ppm
Hartwig’s group subsequently conducted adetailed study to understand the activity and scopeof [Pd(μ-Br)(tBu3P)]2 in the amination of five-membered heterocyclic halides. Variouscombinations of Pd precursors with tBu3P werestudied for a model system, the reaction of N-methylaniline with 3-bromothiophene. Thefastest reaction occurred with the Pd(I) dimer (9).
More recently, Eichman and Stambuli reporteda very interesting zinc-mediated Pd(I) dimer-catalysed C–S coupling, which should generatemuch interest in the area of C–S coupling(Scheme V) (10). For the reactions of alkyl thiolswith aryl bromides and iodides, potassium hydridewas the best base, as illustrated in Scheme V. Forthe Pd-catalysed cross-coupling reactions of aryl
bromides and benzenethiol using zinc chloride incatalytic amounts, with sodium tert-butoxide asthe base, most of the reactions were sluggish andgave low yields. However, the addition of stoi-chiometric amounts of lithium iodide increasedthe rate of the reaction significantly, which isspeculated to be due to the anionic effects pro-posed by Amatore and Jutand (11).
Carbon–Carbon Bond FormationHartwig’s group also studied the Suzuki cou-
pling of sterically hindered tri-substituted arylbromides. A Pd(I) dimer loading of 0.5 mol%, inthe presence of alkali metal hydroxide base, gavegood yields at room temperature within minutes(Scheme VI) (6).
Platinum Metals Rev., 2009, 53, (4) 185
0.5 mol% Pd(I) dimer
NaOtBu, RT
15 min–1 h
R = Bu, Ph
or R2NH = morpholine
R
Yield 88–99%
Cl
R
R
NH +
R
N
Scheme III Arylchloride coupling atroom temperature (6)
Pd catalysts
NaOtBu, Toluene, 110°C
Catalyst loading Yield
[Pd(μ-Br)(tBu3P)]2 0.25 mol% 93%
Pd(OAc)2 + tBu3P 0.5 mol% 86%
Pd(OAc)2 + BINAP 0.5 mol% 27%
Pd(OAc)2 + Xantphos 0.5 mol% 27%
Pd(OAc)2 + DPEphos 0.5 mol% none
Br
+
HN N
Scheme IV Pd(I) dimer-catalysed C–N coupling of N-cyclohexylaniline (8)
0.5–2.0 mol% Pd(I) dimer
THF
ZnCl2 (catalyst)
KH (1.1 equiv.)
X = Br, I
Ar-X + RSH Ar-S-R
Yield 46–99%
R = tBu,
nBu, PhCH2
Scheme V Zinc-mediatedPd(I) dimer-catalysed C–Scoupling (10)
Research work from Ryberg at Astra Zeneca(12) demonstrated a very practical, clean methodfor C–CN coupling using the Pd(I) dimer [Pd(μ-Br)(tBu3P)]2 to produce 3 kg to 7 kg ofproduct routinely (Scheme VII). During the initialin situ studies, Pd2(dba)3 in combination withcommercial ligands such as Q-Phos, tBu2P-biphenyl or Cy2P-biphenyl gave poor results,although with proper process tweaking improve-ments were made. The conventional ligands, suchas Ph3P and dppf, were not useful. However, theP(o-tol)3/Pd2(dba)3 system behaved somewhatwell with the formation of some byproducts. The
Pd loading was as high as 5 mol% (12).For the α-arylation (13) of fairly challenging
carbonyl compounds, Hartwig identified thePd(I) dimer [Pd(μ-Br)(tBu3P)]2 as one of the bestcatalysts, especially for amides and esters. Thework from Hartwig’s group provided generalconditions for α-arylations of esters and amides(14–16). The coupling reactions of aryl halideswith esters are summarised in Scheme VIII (17).For aryl bromides, lithium dicyclohexylamide(LiNCy2) was the best base, while sodium hexa-methyldisilazide (NaHMDS) was required for arylchloride substrates. Intermolecular α-arylation of
Platinum Metals Rev., 2009, 53, (4) 186
Yield 84–95%
0.5 mol% Pd(I) dimer
KOH, THF
15 min, RT
Ph
R1R
2
R3
PhB(OH)2
X
R1R
2
R3
+
Scheme VI Roomtemperature Suzukicoupling of stericallybulky aryl bromides (6)
Pd(I) dimer, Zn(CN)2
Zn, DMF
50ºC, 1–3 hN
HN
Br
OH
N
O
N
HN
NC
OH
N
O
Yield 71–88%R
1, R
2= Me, H; R = Me,
tBu
X = Br, Cl; R3
= Me, MeO, F
(i) LiNCy2 (X = Br) or
NaHMDS (X = Cl)
Toluene, RT, 10 min
(ii) Pd(I) dimer
RT–100ºC, 4 h
R2
R1
R3
O
OR
+
X
R3
O
R1
OR
R2
Scheme VIII α-Arylation of esters under milder conditions using the Pd(I) dimer catalyst (17)
Scheme VIIThe Pd(I)dimer-catalysedcyanationreaction, whichmay be carriedout on akilogram scale(12)
X = Br;
R1
= H, CN, CF3, OCH3 or CH3; R2, R
3= H or CH3
in situ generated zinc enolates of amides was alsoreported in excellent yield under Reformatskyconditions using the Pd(I) dimer, (Scheme IX)(18). The appropriate choice of base for the sub-strate is critical for this reaction.
The α-vinylation of carbonyl compounds hasbeen reported recently by Huang and coworkersat Amgen, catalysed by the Pd(I) dimer in con-junction with lithium hexamethyldisilazide(LiHMDS) base (Scheme X) (19). The same cat-alytic system can be extended to the α-vinylation
of ketones and esters. The combination ofPd2(dba)3 with Buchwald ligands such as X-Phosand S-Phos gave inferior results, as did in situcatalysis with ligands such as Xantphos, (S)-MOP,BINAP and IPr-HCl (carbene) in the presence ofPd2(dba)3. Amgen researchers also reported astereoselective α-arylation of 4-substituted cyclo-hexyl esters using the Pd(I) dimer at roomtemperature, with lithium diisopropylamide(LDA) as the base. Diastereomeric ratios, dr, ofup to 37:1 were achieved (Scheme XI) (20).
Platinum Metals Rev., 2009, 53, (4) 187
Glossary
Ligand Full name
BINAP 2,2' -bis(diphenylphosphino)-1,1' -binaphthyltBu2P-biphenyl 2-(di-tert-butylphosphino)biphenyltBu3 tri-tert-butylphosphine
Cy2P-biphenyl 2-(dicyclohexylphosphino)biphenyl
dba dibenzylideneacetone
DPEphos bis(2-diphenylphosphinophenyl)ether
dppf 1,1' -bis(diphenylphosphino)ferrocene
IPr-HCl (carbene) 1,3-bis-(2,6-diisopropylphenyl)imidazolium chloride
(S)-MOP 2-(diphenylphosphino)-2' -methoxy-1,1' -binaphthyl
OAc acetate
P(o-tol)3 tri(o-tolyl)phosphine
Ph3P triphenylphosphine
Q-Phos 1,2,3,4,5-pentaphenyl-1' -(di-tert-butylphosphino)ferrocene
S-Phos 2-dicyclohexylphosphanyl-2' ,6' -dimethoxybiphenyl
Xantphos 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene
X-Phos 2-dicyclohexylphosphino-2' ,4' ,6' -triisopropylbiphenyl
(i) 1.5 equiv. Zn*
THF, RT, 30 min
(ii) 2.5 mol% Pd(I) dimer
Yield
94%
O
X
NMe2
Br
N
O
NMe2
N
Yield 48–95%
Toluene, 80ºC, 24 h
Pd(I) dimer, LiHMDS
X = Br, OTf, OTs
R1
R3
X
R2
R'''R''R'
OR
1
R2
R3
R'''
R''R'
O
+
Scheme IX α-Arylation ofamides underReformatskyconditions (18);Zn* = activatedzinc species
Scheme X α-Vinylationreaction usingPd(I) dimercatalyst (19);OTf =trifluoromethanesulfonate; OTs = tosylate
ConclusionsThe Pd(I) dimer [Pd(μ-Br)(tBu3P)]2 stands out
as unique among the third generation catalysts forcross-coupling. It has a higher activity than othercatalysts, a fact which can be attributed to its abili-ty to form a 12-electron ‘ligand-Pd(0)’ speciesduring the activation step in the catalytic cycle. Itsapplication to a wide variety of C–C, C–N and C–S
cross-coupling reactions will enable higher yieldsand better product selectivities under relativelymild conditions.
AcknowledgementsFred Hancock and Gerard Compagnoni of
Johnson Matthey’s Catalysis and Chiral Technologiesare acknowledged for their support of this work.
Platinum Metals Rev., 2009, 53, (4) 188
The AuthorDr Thomas J. Colacot is a Research and DevelopmentManager in Homogeneous Catalysis (Global) ofJohnson Matthey’s Catalysis and Chiral Technologiesbusiness unit. Since 2003 his responsibilities includedeveloping and managing a new catalyst developmentprogramme, catalytic organic chemistry processes,scale up, customer presentations and technologytransfers of processes globally.
1 R. Vilar, D. M. P. Mingos and C. J. Cardin, J. Chem.Soc., Dalton Trans., 1996, (23), 4313
2 V. Durà-Vilà, D. M. P. Mingos, R. Vilar, A. J. P. Whiteand D. J. Williams, J. Organomet. Chem., 2000, 600, (1–2),198
3 T. J. Colacot, ‘Di-μ-bromobis(tri-tert-butylphos-phine)dipalladium(I)’, to be included in 2009 in“e-EROS Encyclopedia of Reagents for OrganicSynthesis” , eds. L. A. Paquette, D. Crich, P. L.Fuchs and G. Molander, John Wiley & Sons Ltd.,published online at: www.mrw.interscience.wiley.com/eros (Accessed on 30th July 2009)
4 Johnson Matthey Catalysts, ‘Coupling CatalysisApplication Table’, West Deptford, New Jersey, U.S.A.:http://www.jmcatalysts.com/pharma/pdfs-uploaded/Coupling%20%20Apps%20Table.pdf(Accessed on 30th July 2009)
5 V. Durà-Vilà, D. M. P. Mingos, R. Vilar, A. J. P. Whiteand D. J. Williams, Chem. Commun., 2000, (16), 1525
6 J. P. Stambuli, R. Kuwano and J. F. Hartwig, Angew.Chem. Int. Ed., 2002, 41, (24), 4746
7 R. Kuwano, M. Utsunomiya and J. F. Hartwig, J. Org.Chem., 2002, 67, (18), 6479
8 M. Prashad, X. Y. Mak, Y. Liu and O. Repic, J. Org.Chem., 2003, 68, (3), 1163
9 M. W. Hooper, M. Utsunomiya and J. F. Hartwig, J.Org. Chem., 2003, 68, (7), 2861
10 C. C. Eichman and J. P. Stambuli, J. Org. Chem., 2009,74, (10), 4005
11 C. Amatore and A. Jutand, Acc. Chem. Res., 2000, 33,(5), 314
12 P. Ryberg, Org. Process Res. Dev., 2008, 12, (3), 54013 C. C. C. Johansson and T. J. Colacot, Angew. Chem.,
2009, in press14 T. Hama and J. F. Hartwig, Org. Lett., 2008, 10, (8),
154915 T. Hama and J. F. Hartwig, Org. Lett., 2008, 10, (8),
154516 T. Hama, X. Liu, D. A. Culkin and J. F. Hartwig, J.
Am. Chem. Soc., 2003, 125, (37), 1117617 T. Hama and J. F. Hartwig, Synfacts, 2008, (7), 075018 T. Hama, D. A. Culkin and J. F. Hartwig, J. Am. Chem.
Soc., 2006, 128, (15), 497619 J. Huang, E. Bunel and M. M. Faul, Org. Lett., 2007,
9, (21), 434320 E. A. Bercot, S. Caille, T. M. Bostick, K. Ranganathan,
R. Jensen and M. F. Faul, Org. Lett., 2008, 10, (22),5251
Pd(I) dimer, LDA
Toluene, RT, 3–24 h
Yield 37–85%
Up to 37:1 dr
R1 R
1
CO2Et
R–X+
CO2Et
R
Scheme XI Roomtemperaturediasteroselectiveα-arylation of 4-substitutedcyclohexyl estersusing Pd(I) dimer(20)
References
Palladium is not widely recognised as a preciousmetal in jewellery and watchmaking. Yet, with theprice evolution of precious metals over the lastfew years, use of palladium in these markets hasseen renewed interest (1–3). For illustration, goldwas roughly double the price of palladium in 2006and about four times the price of palladium at theend of 2008 (4). In addition, palladium alloys forjewellery, which usually contain 95 wt.% Pd (950Pd), have a lower density (around 12 g cm–3) than18 carat white gold (close to 15 g cm–3) and 950platinum (about 21 g cm–3). Hence, an item of vol-ume 1 cm3 in 950 Pd contains 11.4 g Pd. Bycomparison, the same item made in 18 carat whitegold (750 Au) or 950 Pt will contain, respectively,11.3 g Au or 20 g Pt.
Furthermore, the 950 Pd alloys approach the‘ideal’ white colour of platinum without requiringrhodium plating like most white gold alloys. Unlikefor gold alloys, the white sheen will therefore notwear off, eliminating the bother and expense of re-plating. 950 Pd alloys also satisfy the generalrequirements for jewellery and watch alloys: they
are nickel-free, malleable, easy to polish, and havedesirable setting and forming characteristics. Theirhigh Pd content also confers good corrosion andtarnishing resistance, a crucial aspect in jewelleryand watchmaking.
The inherently low hardness of Pd alloys is,however, an important technical limitation fortheir use in jewellery and particularly in watchmak-ing. The hardness of existing 950 Pd alloys, withalloying metals such as ruthenium (PdRu), gallium(PdGa) or copper (PdCu), falls between 70 HV(PdCu) and 120 HV (PdGa) in the annealed state,and between 145 HV (PdCu) and 200 HV (PdGa)after 75% strain hardening. These values are sub-stantially lower than those typical of platinum orwhite gold alloys (≥ 130 HV annealed, ≥ 250 HVwork hardened).
In an attempt to develop a 950 Pd single-phasealloy with substantially higher hardness, compara-ble with platinum and white gold, whilemaintaining the favourable colour and workabilityof conventional Pd alloys, we investigated PdAl-based compositions, in particular the PdAlRu
189Platinum Metals Rev., 2009, 53, (4), 189–197
Precious Palladium-Aluminium-BasedAlloys with High Hardness and Workability PROMISING POTENTIAL FOR APPLICATION IN JEWELLERY AND WATCHMAKING
By Julien Brelle and Andreas Blatter*PX Holding SA, R&D, Boulevard des Eplatures 42, CH-2300 La Chaux-de-Fonds, Switzerland;
*E-mail: [email protected]
and René ZiegenhagenCartier Horlogerie, Branch of Richemont International SA, 10 Chemin des Aliziers, CH-2300 La Chaux-de-Fonds, Switzerland
New palladium-aluminium-based alloys with promising potential for application in the areasof jewellery and watchmaking are presented. A particular emphasis is placed on the mechanicalbehaviour of ternary palladium-aluminium-ruthenium (PdAlRu) alloys with 95 wt.% Pd.The new alloys combine high plasticity with high hardness relative to common Pd alloys.The low work-hardening rate enables cold working in excess of 95% reduction withoutintermediate annealing. The hardness (Vickers pyramid indentation) ranges from 100 HV to300 HV in the annealed condition, depending on the Al:Ru ratio. Their whiteness in terms ofcolour coordinates is compared with platinum and white gold. The feasibility of porcelainfusion to PdAlRu for decorative purposes is also demonstrated.
DOI: 10.1595/147106709X472192
system. This paper describes the background tothe alloy development, presents the main charac-teristics of 950 PdAlRu alloys in terms ofmechanical properties and workability, andaddresses the possibility of fusing coloured ceram-ic material to the alloy for decorative purposes.
Background to the Development ofthe PdAlRu Alloys
While precipitation hardening may also be ofinterest to further increase the rigidity and wearresistance of finished components, solid solutionstrengthening is the mechanism that must providethe base hardness of the alloy in the annealed state.
Solid solution strengthening is the result ofstrain produced in the crystal lattice, mainly by thesize misfit between matrix and solute atoms. Sincesize misfit also limits the terminal solid solubility,as described by the Hume-Rothery rules (5), itmust be kept within certain limits to ensure a solu-bility of at least 5 wt.%, which is necessary for a950 Pd single-phase alloy. For a given solute, thestrength increases with its atomic fraction (at.%).Higher atomic fractions are achieved when alloy-ing with light elements. In 950 Pd, for illustration,5 wt.% aluminium corresponds to 17.2 at.%. A 950Pd alloy may include several alloy additions, whichmust be fully soluble and must add up to a total of5 wt.%.
The effects of a great number of solute ele-ments on the hardness of palladium have beencompiled previously (6, 7). Germanium, silicon andboron have a strong hardening effect. However, Bis difficult to alloy and Ge and Si both exhibit near-ly zero solubility. As a result, when added insufficient concentrations to give a hardness above150 HV, these elements tend to precipitate at thegrain boundaries and thereby render the alloy toobrittle for practical use. For those elements whichare more practical in terms of alloying, such asother precious metals or 3d transition metals, thehardness values attained at concentrations of 5wt.% barely exceed 100 HV. Ru is one of the ele-ments showing the most pronounced effect on thehardness of Pd alloys. Hardness values in the range150 HV to 200 HV can be achieved with rare earthmetals such as cerium (8).
With respect to the light elements, 5 wt.% tita-nium raises the hardness to 150 HV (9), while Alboosts the value to 320 HV (440 HV after 80%cold work), according to our own experiments.While a hardness of 150 HV is at the lower edgeof the target range, a value of 320 HV may beinconveniently high for many conventional jew-ellery manufacturing operations such as stampingor setting.
The present study therefore focused on PdAl-based alloys, incorporating ternary additions of Ru,Ti and magnesium in order to moderate the hard-ness. Ru was chosen because it is a noble metal, agood solution hardener, and commonly used in 950Pd alloys. Ti and Mg were chosen because they arelightweight, good solution hardeners, and may pos-sibly provide a mechanism of precipitationhardening by the formation of tiny AlTi or AlMgcompounds upon ageing – in similarity with super-alloys. Table I shows the hardness values obtainedfor various ternary alloys in the annealed and 80%work hardened conditions, respectively. This showsthat the hardness values in the annealed state lie inthe target range and that cold work generates sub-stantial hardening. The values displayed are thosefor ‘low’ and ‘high’ concentrations of the ternaryadditions; intermediate concentrations gave inter-mediate values for hardness. All alloys were singlephase and sufficiently malleable for a rolling reduc-tion of 80% without cracking. It is interesting tonote that there have been two independent patentapplications for 950 PdAl-based alloys (10, 11).
Platinum Metals Rev., 2009, 53, (4) 190
Table I
Vickers Hardness Values of Various PdAl-(Ti, Mg,Ru) Alloys in the Annealed and 80% ReductionWork-Hardened States*
Alloy Hardness, HV
Annealed Work-hardened
Pd95.5Al1.3Ti3.2 154 366Pd95.5Al0.4Ti4.1 128 338Pd95.5Al3.8Mg0.7 242 400Pd95.5Al1.9Mg2.6 170 340Pd95.5Al2.8Ru1.7 224 343Pd95.5Al0.9Ru3.6 158 247
* The standard deviations associated with the displayed meanvalues are below ± 7 HV
The advantage of Ru as the ternary element isthat unlike Mg or Ti, it does not cause a violentreaction with Al upon alloying. In this paper, wefocus on our development work on the 950PdAlRu system.
PropertiesTwo alloys of nominal composition (in wt.%)
Pd95.5Al0.9Ru3.6 and Pd95.5Al2.8Ru1.7 were prepared ina vacuum induction melting unit. The unit cham-ber was evacuated and purged with argon severaltimes before backfilling with argon to 600 mbar.The elemental metals were melted in a zirconiacrucible. The Al flakes were wrapped in Pd sheetsto avoid any reaction with the crucible and also toalloy the Al with the higher melting point Pdwithout significant expulsion of Al. Plate-likeingots of 5 kg each were cast into an oxidised copper mould to constitute the feedstock for thevarious tests. After a first flat rolling, rods werecut off the plate and further rolled to adequatesize for tensile testing while the rest of the platewas used for workability tests and microstructuralinvestigations.
The X-ray diffraction pattern in Figure 1reveals that the ternary alloys are essentially singlephase, face centred cubic (f.c.c.) solid solutions. InRu-rich alloys, a new diffraction peak appears, andits intensity increases with increasing Ru content.Additional peaks, too weak to be seen in Figure 1,become visible when zooming into the data. Thesepeaks, located at scattering angles, 2θ, of 44.0º,
58.3º, 78.2º, 84.8º, and 104.8º, respectively, areclose to those of pure Ru and enable the secondphase to be assigned to a Ru-rich PdRu hexagonalclose packed (h.c.p.) solid solution.
The measured lattice constants, a, of theternary f.c.c. matrix are accurately reproduced witha hard sphere approximation by the linear combi-nation of the atomic sizes, Sj, defined as theminimum interatomic distance in the unit cell ofelement j (Equation (i)):
(i)
where the coefficients cj correspond to the atomicfraction of element j.
The atomic sizes for Pd, Al and Ru are, respec-tively, 2.750 nm, 2.863 nm and 2.650 nm (12).Since Al has a greater atomic size than Pd by4.1%, whereas Ru is smaller by 2.6%, the apparentshift in a is marginal among different ternaryalloys. In other words, strengthening due to latticedistortion is not apparent through a significantshift of the diffraction peaks. In particular, thereexists a ternary composition for which the latticeconstant almost matches that of elemental Pd.The lattice constant derived from the diffractionpattern of Pd95.5Al0.9Ru3.6 is 3.888 nm, compared to3.886 nm for Pd.
Hardness The hardness of the PdAlRu alloys in the
annealed state (1000ºC for one hour), measuredusing a Vickers hardness tester with a 1 kg load
Platinum Metals Rev., 2009, 53, (4) 191
∑⋅=j
jjSca 2
Pd95.5Al0.9Ru3.6
Scattering angle, 2θ
0 20 40 60 80 100 120
Inte
nsity, a.u
.
Fig. 1 X-Ray diffraction patterns ofannealed Pd95.5Al0.9Ru3.6. A θ–2θconfiguration and Cu Kα1 radiation(α = 0.15408 nm) were employed.The sample is predominantly f.c.c.single phase. An additional peak at2θ ≈ 42 indicates the presence of asecond phase
×
(HV1), approximates to a linear function of the Alcontent, as shown in Figure 2. Therefore, thehardness can be tuned to any value from about100 HV (PdRu) to 320 HV (PdAl). The hardnessvalues in the work-hardened condition range from165 HV (PdRu) to 440 HV (PdAl). Correspondingvalues for two ternary compositions are given inTable I. Upon ageing of annealed samples at700ºC for twenty minutes, the hardness of thosealloys with higher Ru content increases slightly,indicating a mechanism of precipitation harden-ing. The intensity of age hardening remainsmodest, however: it approaches but does notexceed the increase of 25 HV observed at thehighest Ru content, i.e. for the binary 950 PdRualloy. This strengthening is also evident in an
increase in yield strength of 50 MPa forPd95.5Al0.9Ru3.6 (Figure 3).
Age hardening is accompanied by a substantialincrease in electrical resistivity, ρel, as measured bymeans of the four-point probe technique on discsof thickness 2 mm and diameter 27 mm (13). ForPd95.5Al0.9Ru3.6, ρel reversibly switches from25.5 μΩ cm in the annealed state to 91 μΩ cm inthe age hardened state. By comparison, the valuesfor Pd95.5Al2.8Ru1.7, which does not exhibit agehardening, are 32.1 μΩ cm and 35.6 μΩ cm,respectively. Since an increase in electrical resistiv-ity is caused by additional scattering of electrons atcrystal imperfections, such as a lattice distortion orthe presence of precipitates, and since age harden-ing occurs with the appearance of a PdRu phase as
Platinum Metals Rev., 2009, 53, (4) 192
R2
= 0.9911
Aluminium, wt.%
01 2 3 4 5 6
50
100
150
200
250
300
350V
ickers
hard
ness, H
V1
y = 42.523x + 109
Fig. 2 Variation of Vickers hardnessvalues, HV1, with Al content x (wt.%)of annealed Pd95AlxRu(5 – x) alloys. Thelinear approximation is shown
Pd95.5Al2.8Ru1.7
Pd95.5Al0.9Ru3.6
Engineering strain, %
Engin
eering s
tress, M
Pa
5 10 15 20 25 30 350
200
400
600
800
1000
1200
CW
AH
AH
AN
AN
Fig. 3 Typicalengineering stress-strain curves recordedfor Pd95.5Al2.8Ru1.7 andPd95.5Al0.9Ru3.6 in theannealed (AN), age-hardened (AH) and85% cold-worked(CW) states
discussed above, it is tempting to correlate agehardening with PdRu precipitates. However, themain diffraction peak of the PdRu phase persistsupon annealing, suggesting that the precipitatesare not fully solubilised.
Figure 4 shows the variation of conventionalyield strength, Rp0.2, ultimate tensile strength, Rm,and fracture strain, A50, with cold work. The alloysundergo significant strain hardening only upon initial cold working. Beyond about 30% of coldwork, yield strengths (Figure 4) and hardness values (Figure 5) remain essentially constant. It isworth mentioning that the tensile properties of theRu-rich alloy after standard annealing (1000ºC for1 hour) depend on its thermomechanical history.
This is no longer the case after cold working. Weattribute this memory behaviour to a variable evo-lution and dissolution of the PdRu precipitates.
The work hardening exponent, n, can be rough-ly estimated from a fit of the Hollomon equation(Equation (ii)) to the true stress-true strain curve(14):
σt = Kεtn (ii)
Here, K, the strength index, is a constant and thetrue stress-true strain data (σt, εt) is obtained fromthe engineering data (σ, ε) by Equations (iii) and (iv):
σt = σ(1 + ε) (iii)
εt = ln(1 + ε) (iv)
Platinum Metals Rev., 2009, 53, (4) 193
Cold work, %
Rm
/Rp
0.2, M
pa
20 40 60 80 1000
200
400
600
800
1000
1200
7
14
21
28
35
42
A50 , %
Pd95.5Al0.9Ru3.6
Pd95.5Al2.8Ru1.7
A50
Rm
Rm
Rp0.2
Rp0.2
0
Pd95.5Al2.8Ru1.7
Pd95.5Al0.9Ru3.6
Cold work, %
Vic
kers
hard
ness, H
V1
350
300
250
200
150
100
50
0 20 40 60 80 100
Fig. 5 Variation of Vickers hardness,HV1, with cold work. Each data pointis the average of five tests (standarddeviation < 5%)
Fig. 4 Yieldstrengths, Rp0.2,ultimate tensilestrengths, Rm, andfracture strains, A50,as derived fromstandard tensiletesting (EN 10002-1:1990) of two PdAlRualloys at variousdegrees of cold work.Each data point is theaverage of five tests(standard deviation < 3% except for A50).Connecting linesserve as a guide tothe eye
where σt is the true stress, σ is the engineeringstress, εt is the true strain and ε is the engineeringstrain.
When applied to the stress-strain curves ofannealed samples in the plastic domain (Figure 3),this approximation returns n = 0.29 forPd95.5Al2.8Ru1.7 and n = 0.25 for Pd95.5Al0.9Ru3.6, val-ues that are typical of low stacking-fault energyalloys such as Al alloys.
Figure 6 depicts the mechanical properties ofPdAlRu alloys in comparison with those of com-mon Pd, Pt or Au alloys. The ternary 950 PdAlRualloys exhibit higher strength and hardness thanconventional 950 PdRu, but lower fracture strains.Tensile strengths and hardness values are similar tothose of Pt or Au alloys. Fracture strains are com-parable or somewhat lower in the annealed state,whereas they are higher after 75% cold work. Yieldstrengths may be somewhat lower or higher in theannealed condition, depending on the Al content.
After cold working, however, the yield strengths ofthe PdAlRu alloys remain largely below those ofthe Pt or Au alloys – another clear manifestation ofthe low work-hardening rate, i.e. the high plasticity,of these ternary alloys.
Young’s modulus, E, and Poisson’s ratio, ν, arelisted in Table II. These elastic properties werededuced from measurements of the longitudinaland transverse sound velocities (15). The pulse-echo measurements were performed on plates2 mm to 3 mm thick, using appropriate transduc-ers to excite either the longitudinal (at 10 MHz) orthe transverse (2.5 MHz) acoustic mode. ThePoisson’s ratio of 0.37 is typical for precious met-als. The Young’s modulus of 139 GPa to 145 GPais comparable to that of the conventional PdRualloy (148 GPa). It lies between those of 18 caratAu alloys (90 GPa to 110 GPa) and 950 Pt alloys(approximately 170 GPa to 210 GPa). Regardingspecific stiffness, E/ρ, the PdAlRu alloys with
Platinum Metals Rev., 2009, 53, (4) 194
CW CW
CW CW
An AH An AH
An AH An AH
Rp
0.2, M
Pa
Rm
, M
Pa
A50, %
Vic
kers
harn
ess, H
V
1000
800
600
400
200
0
0
10
20
30
40
50
0
200
400
600
800
1000
1200
0
50
100
150
200
250
300
350
PtRuGa
5N red gold
PdRu
PdAl2.8Ru1.7 PdAl0.9Ru3.6
AuPdCu 3N yellow gold
Fig. 6 Comparison of mechanical properties of two PdAlRu alloys with commonly used precious metal alloys: a 950 Pt alloy (PtRuGa); a 950 Pd alloy (PdRu); a 13 wt.% Pd-containing 18 carat white gold (AuPdCu); 3N yellowgold; and 5N red gold. The comparison is made for 75% cold-worked (CW), annealed (AN), and age-hardened (AH)materials. Rm = tensile strength; Rp0.2 = conventional yield strength; A50 = fracture strain; HV = Vickers hardness
densities, ρ, in the range 10.5 g cm–3 to 11.6 g cm–3
slightly exceed Pt alloys (ρ ≥ 20 g cm–3) and clearlyoutperform Au alloys (ρ ≥ 15 g cm–3).
Colour The CIELab colorimetric indices L* (lightness),
a* (red-green chromaticity index) and b* (yellow-blue chromaticity index) of polished samples weredetermined using a spectrophotometric colorimeter(Konica Minolta CM-3610d spectrophotometer)(16). The measurement was carried out in a stan-dard configuration with D65 illumination, a 10ºobserver, and in specular component included(SCI) mode. The ideal white would return(L*/a*/b*) indices of (100/0/0). The measuredvalues are (84/1/4.5) for Pd95.5Al2.8Ru1.7 and(86/0.9/4.1) for Pd95.5Al0.9Ru3.6. These values arecomparable to those of standard 950 PdRu, andcloser to the colour of the platinum alloy 950 PtRu(87.7/0.7/3.4) than to ‘premium’ 18 carat whitegold (82/> 1.5/> 6). However, the colour indicesof the two PdAlRu alloys suggest that the effect ofaluminium is to add a slight yellowish tinge and tosomewhat diminish the brightness.
For the classification of white gold alloys, asimple colour grading system based on the ASTMD1925 (1988) yellowness index (YI) has recentlybeen proposed (17). Within this system, the lowerthe YI the whiter the alloy. The whitest metals andalloys such as silver or 950 PtRu have values ofYI ≈ 8. The PdAlRu alloys attain YI ≈ 10, which iscomparable to pure Pd or Pt. White gold alloys, incontrast, have substantially higher indices, atYI ≥ 15.
WorkabilityFigure 4 shows another characteristic feature of
the two PdAlRu alloys: their yield strengths do not
steadily approach their tensile strengths withincreasing cold work. Rather, the gap between thetwo parameters remains relatively large, thus facil-itating the forming of complex and asymmetricshapes.
The good workability of the two alloys wasconfirmed by the fabrication of watch cases, backsand bezels by employing rolling, stamping andannealing operations. Plate ingots with surfacesmachined to eliminate possible microcracks andflaws were used as a starting material. The plateswere easily rolled to over 90% reduction withoutintermediate annealing. In accordance with thedata in Figure 5, the hardness rose by only about40 HV upon increasing the cold work from 23%to 95% reduction. Blanks were then roughlypunched out from bands of thickness 8.8 mm,followed by fine punching for improved surfacefinish and dimensional tolerances. The final shap-ing of larger series of components by progressivedie stamping is in progress.
The most intriguing observation during theseoperations was the pronounced tendency of bothalloys to heat up considerably during plastic work.While heating to a certain extent is usual forrolling processes, the heating up of a disc duringpunching to temperatures so high that it cannotbe touched by hand is extraordinary. This signifi-cant temperature rise during plastic deformationmight be related to the low work hardening bypromoting dynamic recovery.
Use of the Ceramic FusionTechnique with PdAlRu Alloys
Inspired by the dental technique of ceramicveneering of precious metals, the feasibility of fus-ing coloured ceramic overlays on PdAlRu alloysfor decorative purposes was investigated. In the
Platinum Metals Rev., 2009, 53, (4) 195
Table II
Density, Young’s Modulus and Poisson’s Ratio of PdAlRu Alloys
Alloy State Density, Young’s modulus, Poisson’s ratio,
ρ, g cm–3 E, GPa ν
Pd95.5Al2.8Ru1.7 Annealed 10.8 139 0.37
Pd95.5Al0.9Ru3.6 Annealed 11.4 145 0.37
dental technique, Pd-containing alloys are in factpreferred. Pd oxidises more readily than Au or Pt,which guarantees a better bonding to the ceramic.The presence of Al in the PdAlRu alloys is certain-ly favourable in this respect. The dental sectorcommercialises a broad range of ceramic materialswith coefficients of thermal expansion (CTE) inthe range 8 × 10–6 K–1 to 14 × 10–6 K–1 (18, 19). TheCTE of Pd is 12 × 10–6 K–1, and alloying with atotal of 5 wt.% Al and Ru is not expected tochange this value significantly. A close match ofthe ceramic CTE to the metal CTE is important toavoid cracking, notably during cooling after thefiring process.
Two types of commercial dental ceramics weretested: VITA VM®13 veneering material for inten-sive or translucent colours, and the VITA Akzent®
stain powder for pitch black dyeing (19). Theceramics were either applied as overlays or filled into trench patterns machined into the PdAlRudiscs.
The ceramic-to-metal fusion was performedfollowing the directions of the ceramic supplier(19). In short, it consists of preparing the metalsurface by sandblasting and controlled thermaloxidation. Different ceramic layers are thenapplied and fired one after the other at 890ºC forone to two minutes: a first layer to promote cohe-sion, a second opaque layer, and a finalglass-ceramic coloured layer. Additional layersmay be necessary in order to fill in possible gapsproduced upon firing.
Figure 7 exemplifies PdAlRu discs preparedand polished by the methods described above,with differently coloured ceramic inlays. Thecolours are uniform and no pores or cracks areapparent.
ConclusionsIn search of 950 Pd alloys with improved
mechanical properties, PdAlRu alloys proved partic-ularly promising. The PdAlRu alloys presented inthis paper possess beneficial characteristics forapplications in jewellery, and in particular in watch-making. The palladium content of 95 wt.% iscommon to most countries. The PdAlRu alloys arewhiter than most 18 carat white gold alloys.Furthermore, they are compatible with the dentalveneering technique, which opens up the potentialfor decorating articles with ceramic ornaments inappealing colours. The PdAlRu alloys exhibit excel-lent workability and forming characteristics, similarto those of commonly used 950 Pd alloys. At thesame time, they exhibit much higher strength andhardness, more comparable to those of gold or plat-inum alloys. Moreover, the mechanical propertiescan be tuned in an extended range by varying theAl:Ru ratio. Upon cold working, for a given strain,the yield stress increases much less than it does inother precious metals, while the tensile strengthincreases in broadly similar fashion. This character-istic imparts to the alloys enhanced plasticity andexcellent workability.
Platinum Metals Rev., 2009, 53, (4) 196
Fig. 7 PdAlRu alloy discs with ceramic inlays
1 S. A. Forrest and B. Clarke, ‘End-Users, Recyclers andProducers: Shaping Tomorrow’s PGM Market andMetal Prices’, in “International Platinum Conference‘Platinum Surges Ahead’”, Sun City, South Africa,8th–12th October, 2006, Symposium Series S45, TheSouthern African Institute of Mining and Metallurgy,Johannesburg, South Africa, 2006, p. 307
2 B. Libby, ‘Palladium Premieres’, MJSA Journal, March2006, p. 35
3 “The Santa Fe Symposium on Jewelry ManufacturingTechnology 2008”, ed. E. Bell, Proceedings of the22nd Symposium in Albuquerque, New Mexico,U.S.A., 18th–21st May, 2008, Met-Chem ResearchInc, Albuquerque, New Mexico, U.S.A., 2008
4 Kitco, Inc, Past Historical London Fix: http://www.kitco.com/gold.londonfix.html (Accessed on3rd July 2009)
5 W. Hume-Rothery, R. E. Smallman and C. W. Haworth,
References
“The Structure of Metals and Alloys”, 5th Edn., TheMetals and Metallurgy Trust, London, U.K., 1969,407 pp
6 G. Beck, in “Edelmetall-Taschenbuch”, 2nd Edn., ed.A. G. Degussa, Hüthig-Verlag, Heidelberg, Germany,1995, p. 217
7 The PGM Database:http://www.platinummetalsreview.com/jmpgm/index.jsp (Accessed on 3rd July 2009)
8 J. R. Hirst, M. L. H. Wise, D. Fort, J. P. G. Farr andI. R. Harris, J. Less-Common Met., 1976, 49, 193
9 J. Evans, I. R. Harris and L. S. Guzei, J. Less-CommonMet., 1979, 64, (2), P39
10 A. Blatter, J. Brelle and R. Ziegenhagen, PX HoldingSA, ‘Alliage à Base de Palladium’, Swiss Appl.CH00032/08; 2008
11 P. Battaini, 8853 SpA, ‘High-Hardness Palladium Alloyfor Use in Goldsmith and Jeweller’s Art andManufacturing Process Thereof’, Italian Appl.TO2006/0086; U.S. Appl. 2008/0,063,556
12 H. W. King, Bull. Alloy Phase Diagrams, 1982, 2, (4),527
13 F. M. Smits, Bell Syst. Tech. J., 1958, 37, 711
14 R. Hill, “The Mathematical Theory of Plasticity”,Oxford Classic Texts in the Physical Sciences, OxfordUniversity Press Inc, New York, U.S.A., 1998, 366 pp
15 “Nondestructive Testing Handbook”, Volume 7,“Ultrasonic Testing”, eds. A. S. Birks, R. E. Green,Jr. and P. McIntire, American Society forNondestructive Testing, Columbus, Ohio, U.S.A.,2007, 600 pp
16 “Precise Color Communication: Color Control fromPerception to Instrumentation”, Product Applications,Konica Minolta Sensing Inc, Japan, 1998: http://www.konicaminolta.com/instruments/knowledge/color/pdf/color_communication.pdf (Accessed on3rd July 2009)
17 S. Henderson and D. Manchanda, Gold Bull., 2005,38, (2), 55
18 Wieland Dental online: Products: Veneering Ceramic:http://www.wieland-dental.de/produkte/verblendkeramik/page.html?L=1 (Accessed on 3rdJuly 2009)
19 VITA Zahnfabrik website: http://www.vita-zahnfabrik.com/ (Accessed on 3rd July 2009)
Platinum Metals Rev., 2009, 53, (4) 197
The Authors
Julien Brelle graduated in MaterialsScience and Engineering from theÉcole Polytechnique Fédérale inLausanne, Switzerland (2005), with aspecialisation in metal matrixcomposites. He is now working as aResearch Engineer at PX Group, aproducer of metal products for thewatch, jewellery and medical sectors.He is mainly involved in the
development of speciality alloys and related processing.
After his Ph.D. in Physics (1986),Andreas Blatter led a research group atthe Institute of Applied Physics in Berne,Switzerland, and spent a year at the IBMAlmaden Research Center, U.S.A, as aVisiting Scientist. His research wasfocused on non-equilibrium laserprocessing, thin films and metallicglasses. Since 1996, he has been theR&D Director of PX Group. His main
research topics include precious metals and speciality alloysand their related technologies, as well as corrosion andbiocompatibility studies.
René Ziegenhagen received his degree inMaterials Science and Engineering fromthe École Polytechnique Fédérale inLausanne, Switzerland (1986). He wasthen involved in the research of preciousmetals and the development of newindustrial processes, such as metalinjection moulding and forging, beforejoining Cartier in the Richemont Group asa Senior Project Manager. At Cartier, his
main concerns include the quest for new materials and newproduction technologies to meet requirements and regulationson biocompatibility and ecotoxicity.
198
The 23rd annual Santa Fe Symposium® was heldin Albuquerque, New Mexico, U.S.A., from17th–20th May 2009 (1). Attendance was down onprevious years, perhaps reflecting the impact of thecurrent recession on the jewellery industry in theU.S.A., although surprisingly representation fromEurope was stronger than in previous years. Onceagain, the organisers had put together a strong,attractive programme covering all areas of activity,although platinum- and palladium-centred topicswere fewer than last year. Having said that,palladium’s position as a relatively new metal forjewellery sustained its prominence at the conference.
The Platinum Group MetalsThe interest in platinum group metals (pgms)
remains strong, judging by the reaction to the lucidpresentation by Mark Danks (Johnson MattheyNew York, U.S.A.). His topic was ‘The PreciousMetal Price Equation’ and he reviewed the pricehistory of platinum and palladium, coinciding withPlatinum Week in London, U.K., and the publica-tion of the Johnson Matthey “Platinum 2009”market review (2). 2008 was a year of mixed for-tunes, with the price of platinum starting high,rising even further during the first half-year beforedropping severely during the third quarter due tosoftening demand in both the industrial and jew-ellery sectors, although there was some recovery atthe year end. Danks analysed the supply anddemand for platinum and palladium and the rea-sons behind the changes compared to 2007. Hecovered the fall in demand from the automotivesector, the rise in exchange traded funds (ETFs)and examined trends in jewellery demand for plat-inum and palladium. The high price of platinuminevitably had a negative impact on jewellerydemand, while demand for palladium in this sector
increased in Europe and the U.S.A., due toimproved technical knowledge of the metal and itsfavourable price compared to gold and platinum.
Palladium On the technical side, Paolo Battaini (8853
SpA, Italy) gave another excellent presentation onthe casting of 950 palladium alloys, using an inno-vative melting technique borrowed from the dentalindustry. Titled ‘Production of Hard 950Palladium-Based Jewellery Using an Arc MeltingMethod under Argon Protection’, Battaini showedhow employing arc plasmas for melting (as in tung-sten inert gas (TIG) welding) in the investmentcasting of palladium jewellery can overcome someof the problems found with conventional castingprocesses. In particular, it enables good control ofthe melting and casting atmosphere as well asallowing rapid melting to the high temperaturesrequired. Use of argon gas is preferred over heliumto avoid overheating of the melt. Casting trialswere carried out on a hard 950 palladium alloy con-taining gallium, indium and other minor alloyingadditions. The alloy development was described inBattaini’s earlier paper, presented in 2006 (3): inthe as-cast condition, it has a Vickers hardness of190 HV.
Casting was carried out in an Orotig Srl‘Speedcast 220MJ’ machine, which is also used tocast platinum and titanium jewellery. Casting isaccomplished by rotating the chamber to gravity filland applying an argon overpressure to the castingmould and flask. During melting, the tungsten elec-trode is moved over the melt in a circular motion.Three types of melting crucible were trialled: alumi-na, fused quartz (silica) and zirconia, along withfour types of mould investment: a two-part phos-phate-bonded, quick burn-out dental investment, a
Platinum Metals Rev., 2009, 53, (4), 198–202
The 23rd Santa Fe Symposium on JewelryManufacturing TechnologyNOVEL MELTING APPROACH FOR 950 PALLADIUM CASTINGS SHOWS PROMISE
Reviewed by Christopher W. CortiCOReGOLD Technology Consultancy, Reading, U.K.; E-mail: [email protected]
DOI: 10.1595/147106709X474208
one-part water-bonded platinum investment con-taining chopped glass fibres, the same without glassfibres, and a two-part phosphoric acid-bondedinvestment for platinum. The arc current employedwas related to the melt size and casting was accom-plished in about forty seconds after arc ignition.Zirconia crucibles were preferred for melting asless current is needed (due to zirconia’s lower ther-mal diffusivity compared to silica and alumina),allowing for better process control.
Castings were evaluated for pattern filling, sur-face quality and defects, including cracks, fins andporosity; additionally, metallographic examinationand mechanical property assessments were made.Other factors such as devesting of the castingsand recastability of scrap were also examined. Ingeneral, the two-part platinum investment gavethe best results for the 950 palladium alloy. Detailreproduction was good with a smooth surface(Figure 1), and there was no reaction between
metal and investment. Flask temperature (650ºCand 750ºC) made little difference to the slight oxi-dation observed, although if higher temperaturesare used a vitreous layer may be formed. The two-part dental investment resulted in castings withheavy oxidation and hot tearing. The latter prob-lem was also seen with the glass fibre-containinginvestment, suggesting that both investments havepoor thermal expansion compatibility and/or toohigh a level of stiffness.
Pattern filling was generally good with allinvestments, attributed to the argon overpressureapplied just after pouring. Recastability was good,even with use of 100% scrap as the charge if prop-erly cleaned. Normal casting results in largedendritic grains, but in this study metallographicexamination revealed a moderate as-cast grain sizeof about 300 μm, with some microsegregationacross dendrites. The grain size increased a little inthicker sections.
Platinum Metals Rev., 2009, 53, (4) 199
2 mm
500 μm
1 mm
1 mm
2 mm
Fig. 1 As-cast surfaces of the 950 palladium alloy after water jet removal of the two-part platinum investment. Surfaceis smooth, with slight defects in the wax reproduced – particularly evident on the grid. (Inset: Scanning electronmicroscope image of the grid. The black particles are the only remaining traces of the investment material)(Courtesy of Paolo Battaini, 8853 SpA, Italy)
Gas porosity was noted frequently but washardly detected after polishing. Care was neededto avoid shrinkage porosity in thick (> 3 mm) sec-tions, but the normal precautions to prevent thisoccurrence in other precious metals also work forpalladium alloys. Battaini noted that the feedsprues should be optimised to assist directionalsolidification. He concluded that arc meltingproved to be a reliable method for investmentcasting of this 950 palladium alloy, and that shortmelting times and an argon atmosphere help toavoid alloy contamination. He also reiterated thatthe right choice of investment remains essentialto obtain good results and recommended that aspecific investment tailored for palladium shouldbe developed.
Platinum On the platinum front, technology is more
established and attracted less attention. However,Jurgen Maerz (Platinum Guild International,U.S.A.) gave an interesting presentation on theinvestment casting of 950 platinum alloys,‘Historic Casting Methods’. This was a review ofold methods used to cast platinum in the early daysof jewellery making and, more specifically, of aproject in which the old manual sling castingmethod was reproduced in a modern guise andshown to produce acceptable castings. It was wellillustrated by a video clip of the whole process. Itis something only likely to be used by the smallcraft jeweller – however, whirling hot molten plat-inum around one’s head may not meet modernworkplace health and safety requirements!
Metallurgy and ManufacturingA number of papers were presented that cov-
ered all the jewellery precious metals: gold, silver,platinum and palladium. Starting the conference,Chris Corti (COReGOLD, U.K.) gave the thirdpart of his ongoing ‘Basic Metallurgy’ series on‘Cracks, Defects and Their Prevention’ (4, 5). Thisexamined the causes of cracking and other defectscommonly encountered while manufacturing jew-ellery. These included embrittlement by impuritiesand minor alloying additions such as silicon, whichcan manifest itself as hot tearing and quench
cracking during casting; these can occur in all fourprecious metals. Other causes include cracking dueto shrinkage porosity, inclusions and pipes fromcasting, and fire cracking from annealing. Stresscorrosion cracking can occur after manufacture,when the jewellery is in service.
Hardness and its significance was a populartopic in 2008 (6), and it continued to attract atten-tion in 2009. Gary Dawson (Goldworks JewelryArt Studio, U.S.A.) examined the effect of bur-nishing jewellery on hardness of the surface layerfor a range of materials, including 950 platinumand 950 palladium alloys. This utilised the ‘drophardness’ test to determine hardness, which is easyto do in the absence of proper hardness testingequipment. This study concluded that, as had beenfound earlier, burnishing with steel media in eithera rotary tumbler or vibratory machine leads tohardening of the surface, rotary tumbling having alarger effect and giving a smoother surface. Thedepth of hardening was lower for the 950 platinumalloy than for the 950 palladium alloy, althoughboth saw larger relative hardness increases thanthe gold or silver alloys tested. Dawson noted thatfinal polishing after burnishing could remove thehardened layer.
‘Hardness and Hardenability’ was a topic pre-sented by John Wright (Wilson-Wright Associates,U.K.), author of the Johnson Matthey jewellerytechnical manual “An Introduction to Platinum”(7). He investigated the indentation hardness testand how work hardening affects the value mea-sured, and explained why it is not easy to correlateresults measured by one test with those measuredby another type, or with tensile data.
Improved wear, scratch and tarnish resistancesof jewellery are desirable features in jewellery man-ufacture. Marco Actis Grande (Turin Polytechnic,Italy) spoke about ‘Transparent Coatings Appliedin Jewellery: A Challenge for Success?’. Using plasma-enhanced chemical vapour deposition(PECVD), he deposited thin non-stoichiometricsilicon oxide coatings on sterling silver and per-formed a range of corrosion, tarnish and weartests. These showed that a 100 nm-thick coatinggave the best improvement in resistance to corro-sion and tarnish. Actis Grande concluded that
Platinum Metals Rev., 2009, 53, (4) 200
PECVD can be one method to improve corrosionand tarnish resistance of sterling silver. Wear testresults are awaited. These coatings may have appli-cation to the other precious metals for improvedwear resistance, especially where the alloys are relatively soft.
Looking to the future, Joe Strauss (HJECompany, Inc, U.S.A.) gave an excellent reviewof how rapid prototyping is developing into amanufacturing process, in ‘Rapid Manufacturing(RM) and Precious Metals’. Noting that computeraided design/computer aided manufacturing(CAD/CAM) and rapid prototyping are becomingfamiliar technologies in the jewellery industry, helooked at how these technologies are being devel-oped into manufacturing processes and how thesemight relate to jewellery manufacture in the future.There are a number of RM technologies emerging,many based on metal powders as the starting mate-rial: selective laser fusing and sintering, electronbeam melting, laser powder forming and selectiveinkjet binding. These techniques are already in usein dental, biomedical, Formula 1 motor racing andthree-dimensional artwork applications, where theattraction is the ability to customise components.Strauss believes that the use of these techniques injewellery manufacture should have the objective ofutilising their key attributes, namely: reduction oflead time to market, the creation of unique shapes,the use of novel materials and the possibility forinnovative design features, rather than competingwith current manufacturing technologies. Thereare some challenges and issues, he admitted, suchas quality of surface finish, affordability of equip-ment and material costs and availability.
Investment casting is probably the most widelyused manufacturing process in jewellery. It com-prises many steps, starting with master models andrubber mould manufacture. Tyler Teague (JettResearch, U.S.A.) gave an excellent paper,‘Technical Model Making (It’s Not Just the Size ofYour Sprue That Counts)’, which examined vari-ous factors including the adaptation of traditionalcasting techniques to jewellery, in particular the useof risers, to prevent shrinkage porosity. HubertSchuster (Consultant, Italy) looked at rubbermould manufacture in his absorbing presentation
‘Innovative Mould Preparation and Cutting forVery Thin and High Precision Items’. Thisinvolved use of different rubber compounds inparts of the mould and expert cutting after vulcan-ising.
General InterestBack to basics once again with Klaus Wiesner
(Wieland Dental + Technik GmbH & Co KG,Germany) who gave an overview of precious metaltube manufacturing techniques and some of theproblems encountered, in his presentation ‘TubeManufacturing – Some Basics’.
There were several presentations on decorativeeffects in jewellery: purple and blue gold alloyswere discussed by Ulrich Klotz (FEM, Germany)and Jörg Fischer-Bühner (Legor Srl, Italy); a pre-sentation on an ancient Japanese technique knownas ‘mokume gane’ that bonds many layers of pre-cious metals into a single patterned piece was givenby Chris Ploof (Chris Ploof Studio, U.S.A.) (Figure2) (8); a description of colour gradients in carat
Platinum Metals Rev., 2009, 53, (4) 201
Fig. 2 Triple white mokume gane ring, with 950palladium alloy, 14 carat palladium white gold and silver(Courtesy of Chris Ploof Studio, U.S.A.)
golds by gradient casting was given by Filipe Silva(University of Minho, Portugal); and a scientificstudy of Japanese patination techniques was pre-sented by Cóilín Ó Dubhghaill and Hywel Jones(Sheffield Hallam University, U.K.).
Other papers included a study of the practicalapplication of some new (tarnish-resistant) sterlingsilvers by Mark Grimwade (The WorshipfulCompany of Goldsmiths, U.K.), and discussionsof electromechanical polishing of silver by AlexVerdooren (Rio Grande, U.S.A.) and hot tearing incasting sterling silver by Daniele Maggian(ProGold Srl, Italy). These were followed by areview of gold-filled products by Rick Greinke(Award Concepts, Inc, U.S.A.), and by the discus-sion of unconventional manufacturing techniquesfor models and prototypes by Michael Jones(Evangel Arts, U.S.A.), age-hardenable carat goldsby Grigory Raykhtsaum (Sigmund Cohn Corp,U.S.A.) and design of fire assay laboratories byRajesh Mishra (A-1 Specialized Services andSupplies, Inc, U.S.A.).
A Lifetime Achievement Award was presentedto John C. Wright, who has made a significantcontribution over many years to further ourknowledge and understanding in jewellery manu-facture, particularly in platinum (see for example(7, 9)). Professor Wright has presented severaltimes at the Symposium, and also wrote the WorldGold Council “Technical Manual for GoldJewellery” (10).
Concluding RemarksInterest in palladium as a new jewellery metal
remains high, while platinum technology is betterknown and established. The conference continuesto provide good coverage of general techniques injewellery manufacture, of interest to workers in allthe precious metals. The Santa Fe Symposium®
proceedings are published as a book and thePowerPoint® presentations are available on CD-ROM. They can be obtained from the organisers(1). The 24th Santa Fe Symposium will be held inAlbuquerque on 16th–19th May 2010.
Platinum Metals Rev., 2009, 53, (4) 202
The ReviewerChristopher Corti holds a Ph.D. in Metallurgyfrom the University of Surrey (U.K.) and hasrecently retired from the World Gold Councilafter thirteen years, the last five as aconsultant. During this period, he served asEditor of Gold Technology magazine, GoldBulletin journal and the Goldsmith’s CompanyTechnical Bulletin. He continues to consult inthe field of jewellery technology and, as arecipient of the Santa Fe Symposium®
Research, Technology and Ambassador Awards, he is a frequentpresenter at the Santa Fe Symposium.
1 The Sante Fe Symposium:http://www.santafesymposium.org/ (Accessed on3rd August 2009)
2 D. Jollie, “Platinum 2009”, Johnson Matthey, Royston,U.K., 2009: http://www.platinum.matthey.com/publications/Pt2009.html (Accessed on 3rd August2009)
3 C. W. Corti, Platinum Metals Rev., 2007, 51, (1), 194 C. W. Corti, ‘Basic Metallurgy of the Precious Metals’,
in “The Santa Fe Symposium on JewelryManufacturing Technology 2007”, ed. E. Bell,Proceedings of the 21st Symposium in Albuquerque,New Mexico, U.S.A., 20th–23rd May, 2007, Met-ChemResearch Inc, Albuquerque, New Mexico, U.S.A., 2007,pp. 77–108
5 C. W. Corti, ‘Basic Metallurgy of the Precious Metals– Part II’, in “The Santa Fe Symposium on Jewelry
Manufacturing Technology 2008”, ed. E. Bell,Proceedings of the 22nd Symposium in Albuquerque,New Mexico, U.S.A., 18th–21st May, 2008, Met-ChemResearch Inc, Albuquerque, New Mexico, U.S.A., 2008, pp. 81–101
6 C. W. Corti, Platinum Metals Rev., 2009, 53, (1), 217 “An Introduction to Platinum”, Johnson Matthey New
York, U.S.A.: http://www.johnsonmattheyny.com/technical/platinumTechManual (Accessed on 3rdAugust 2009)
8 Chris Ploof Studio, Traditional Mokume Gane:http://www.chrisploof.com/traditionalpattern.html(Accessed on 3rd August 2009)
9 J. C. Wright, Platinum Metals Rev., 2002, 46, (2), 6610 J. C. Wright, “Technical Manual for Gold Jewellery –
A practical guide to gold jewellery manufacturingtechnology”, World Gold Council, London, U.K., 1997
References
The third Novel Chiral Chemistries Japan(NCCJapan) Conference and Exhibition was heldin Tokyo on 18th and 19th April 2009 (1). The sec-ond meeting had been held in 2007 (2) and the firstin 2006. All meetings in the series have followed asimilar format, with keynote addresses and sup-porting lectures, although this time there weresome dual presentations in which two speakersfrom the same company gave complementary talkson slightly different topics within a single time slot.Professor Takao Ikariya (Tokyo Institute ofTechnology, Japan) and his team, in particularKyoko Suzuki, must be congratulated for theexcellent job they did to ensure that the conferenceran smoothly. As in previous meetings, ProfessorIkariya put together an exciting mix of speakersfrom both academia and industry across the world.There were around 130 attendees, with the major-ity being from Japan.
During the coffee and lunch breaks there wasan exhibition by companies with products mainlyassociated with chiral chemistry. The exhibitorsranged from companies that provide biocatalystsand chemical catalysts including ligands, to chro-matography, chemistry services and instrumentmanufacturers.
Keynote PresentationsThe opening keynote address was given by
Professor Yoshiji Takemoto (Kyoto University,Japan) on asymmetric catalysis with multifunction-al ureas. The reactions described includedasymmetric versions of the Michael and Mannichreactions, hydrazination and the aza-Henry reac-tion with 1,3-dicarbonyl compounds, as well asPetasis-type additions to quinolines and conjugateadditions to enones.
The second keynote address was given byProfessor Jan-Erling Bäckvall (Stockholm Univer-sity, Sweden). This lecture covered his work on the
simultaneous use of bio- and chemocatalysis toenable dynamic kinetic resolutions (DKR) to becarried out. The initial work was performed withsecondary alcohols. The readily available enzyme,Candida antarctica lipase B (CALB) (Novozym®
435), which is derived from a yeast, is used to acy-late one enantiomer of a secondary alcohol. Aruthenium catalyst then racemises the unreactedenantiomer. Initially the Shvo catalyst, 1, was usedbut the racemisation is slow and requires heating togive acceptable reaction rates. Use of themonomeric ruthenium catalyst 2 provides fasterreactions, even at ambient temperatures.
CALB provides the (R)-acetate, while a spe-cially treated subtilisin Carlsberg enzyme gives the(S)-product ester. With 1,3-dihydroxy com-pounds, the selectivity of the enzyme ensures highselectivity for the (R,R)-diacetoxy product.However, due to the slow racemisation rates withthe Shvo catalyst system, significant amounts ofmeso-products were formed with 1,4- and 1,5-diols.Use of the faster catalyst 2 alleviates this problem.Analogous uses of the concept have beenemployed for the DKR of chlorohydrins, aminesand allenic alcohols.
203Platinum Metals Rev., 2009, 53, (4), 203–208
Novel Chiral Chemistries Japan 2009PGMs RETAIN THEIR PIVOTAL ROLE IN ASYMMETRIC CATALYSIS
Reviewed by David J. AgerDSM, PMB 150, 9650 Strickland Road, Suite 103, Raleigh, NC 27615, U.S.A.; E-mail: [email protected]
DOI: 10.1595/147106709X474226
RuH
Ru
OH
O
Ph
Ph
Ph
Ph
Ph
PhPh
Ph
OCCOCO OC1
RuCl
Ph
Ph
Ph
Ph
Ph
OCCO2
The third keynote address was given byProfessor Hisashi Yamamoto (University ofChicago, U.S.A.) on the uses of Brønsted acids inorganic synthesis. The emphasis of the talk was onthe use of triflimide, (CF3SO2)2NH, as a superacidthat can regenerate itself during a Mukaiyama aldolreaction. The use of the tris(trimethylsilyl)silyl(TTMS) group as a ‘super silyl’ group also makesthe enol ether more reactive.
Asymmetric CatalysisIn addition to these keynote addresses there
were fifteen other presentations. Topics includedthe uses of biocatalysis, transition metal catalysisand the synthesis of target molecules, among others. In line with the emphasis of this publica-tion, those talks relating to the use of platinumgroup metals (pgms) have been highlighted.
Fred Hancock (Johnson Matthey Catalysis andChiral Technologies, U.K.) gave an overview ofsome case histories in which Johnson Matthey hadlooked for an appropriate catalyst to perform anasymmetric transformation. He described theadvantages of chemocatalytic and enzymatic meth-ods for the reduction of carbonyl compounds fora number of example systems. The reduction ofaryl ketones can be achieved in high yield and withhigh enantioselectivity by the system RuCl2[(R)-P-Phos][(S)-DAIPEN], 3a and 4, in a manner anal-ogous to the method developed by Noyori (3). Theuse of this system with xyl-P-Phos, 3b, was illus-trated for a pharmaceutical application as part ofthe synthesis of Nycomed’s imidazo[1,2-a]pyridineBYK-311319. The P-Phos family of ligands canalso be used in the catalyst system [RuCl2(P-Phos)(DMF)n] (DMF = N,N-dimethylformamide),
for the reduction of α,β- and γ,δ-enoic acids forpharmaceutical applications, such as in the preparation of an intermediate for Solvay’sSONU 20250180. α,β-Enoic acids can also bereduced by an iridium or rhodium catalyst withMe-BoPhozTM, 5, as the chiral ligand or by arhodium–Xyl-PhanePhos, 6, system.
André de Vries and David Ager (DSM, TheNetherlands and U.S.A., respectively) gave a jointpresentation. de Vries described the advantages ofperforming asymmetric hydrogenations of unsatu-rated carbon–carbon multiple bonds with arhodium catalyst using the MonoPhosTM family ofligands, 7 (4). The method can be automated,which allows for rapid screening of products.
Platinum Metals Rev., 2009, 53, (4) 204
N
N
OMe
MeO
MeO
OMe
PAr2
PAr2
3
a Ar = Ph ((R)-P-Phos)
b Ar = xyl ((R)-xyl-P-Phos)
H2N
H2NOMe
OMe
4 (S)-DAIPEN
Fe
N
PPh2 PPh2
5 (R)-Me-BoPhozTM
P(xyl)2
P(xyl)2
6 (R)-Xyl-PhanePhos
R4
R4
R3
O
O
R3
R5
R5
P NR1R
2
7 MonoPhosTM
family of ligands
Higher reaction rates and enantioselectivities canbe observed when two different monodentate lig-ands are used at the same time. This has resultedin an economical process for the preparation ofpart of Novartis’ renin inhibitor, Aliskiren. Thephosphoramidite MonoPhosTM ligands are alsouseful for the reduction of carbonyl groups,including β-keto esters, with ruthenium as themetal. Iridium systems with phosphoramidites canbe used to prepare phenylalanines by asymmetrichydrogenation, and also provide high selectivity inthe reduction of imines. Ager discussed enzymaticmethods to prepare cyanohydrins with high enan-tioselectivity, and the development of theindustrial production of DSM’s PharmaPLETM, arecombinant pig liver esterase that can be used inpharmaceutical applications.
Professor Andreas Pfaltz (University of Basel,Switzerland) continued the asymmetric hydro-genation theme with his iridium-catalysedasymmetric reduction of unfunctionalised alkenesin the presence of P,N-ligands. In addition to thewell-established system 8, which can be used witha wide variety of alkene substitution patterns, thephosphinooxazolines, 9, have also proven useful,particularly with trisubstituted alkenes. For thisclass of reductions, it is particularly important touse a non-nucleophilic counterion for the metal,such as tetra[3,5-bis(trifluoromethyl)phenyl]borate(BArF).
Kunihiko Murata (Kanto Chemical Co, Inc,Japan) described the development of the rutheni-um-based asymmetric transfer hydrogenationcatalyst 10 for the reduction of ketones, whichremoves the need for a chiral phosphine ligand.The diamine provides the asymmetry. This catalystcan also be used to carry out asymmetric Henryand Michael reactions.
Ian Lennon (Chiral Quest, Inc, U.K.) describedthe chemistry and uses of a number of ligand sys-tems developed by Chiral Quest. C3-TunePhos, 11,provides excellent enantioselectivity for the reduc-tion of β-keto esters. The analogue C3*-TunePhos,12, extends this to ketones and α-keto esters aswell as retaining its selectivity with β-keto esters.TangPhos, 13, has proven to be a useful ligand inthe rhodium-catalysed reduction of dehydroaminoacids, itaconates and enamides. The latter class ofcompounds can now be accessed from oximes bya rhodium-on-carbon-catalysed hydrogenation inthe presence of acetic anhydride. The analogue ofTangPhos, DuanPhos, 14, provides excellentstereoselectivity for the reduction of function-alised aryl alkyl ketones, while BINAPINE, 15,provides access to β-amino esters.
Christophe Le Ret (Umicore AG & Co KG,Germany) described a different aspect of asym-metric hydrogenation: the formation ofmetal–ligand complexes and the influence of themetal precursor. For rhodium, an example ligandwas MandyPhosTM, 16. For the asymmetricreduction of (Z)-acetamidocinnamic acid methylester, with Rh(nbd)2 (nbd = 2,5-norbornadiene)as the metal source, in situ formation of the cata-lyst or the use of the P,N-complex gave a slowerhydrogenation rate than the P,P-complex system.With ruthenium, it was found that the use ofbis(η5-2,4-dimethylpentadienyl)ruthenium(II), 17,was superior for complex formation withMandyPhosTM and other ferrocene-based ligands.
Wataru Kuriyama (Takasago InternationalCorp, Japan) described the synthesis of chiral alco-hols by the catalytic reduction of esters. The systemis based on a ruthenium–diamine complex, 18. Forhigh enantioselectivity, the stereogenic centre hasto be present in the substrate, as it is in α-alkyl, β-amino, β-alkoxy, β-hydroxy and α-hydroxy esters.
Platinum Metals Rev., 2009, 53, (4) 205
PAr2 N
O
R2
N
O
PAr2
Ph3
8 9
Ar = Ph or o-Tol
NH2
N
Ru
Ph
Ph X
R1SO2
R2
10
X = Cl
R1
= aryl or alkyl
Ar–R2
= cymene,
mesitylene or
hexamethylbenzene
The key to success was performing the reactions inthe absence of base.
Professor Ken Tanaka (Tokyo University ofAgriculture and Technology, Japan) presented onrhodium-catalysed [2 + 2 + 2] cycloadditions forthe preparation of axial chiral aromatic compounds.The products can be biaryl systems or others withhindered rotation, such as benzamides. The ligandsused for the reactions are BINAP, 19, and deriva-tives, such as H8-BINAP, 20, and SEGPHOS®, 21.
David Chaplin (Dr Reddy’s Laboratories Ltd,U.K.) described asymmetric hydroformylationreactions. Linear products are most commonlyformed from an achiral hydroformylation reaction,but the product aldehydes can be substrates for awide variety of reactions. For an asymmetric version of the reaction, regioselectivity as well asenantioselectivity must be considered, as thebranched aldehyde is usually the required productbecause it generates the stereogenic centre. This
Platinum Metals Rev., 2009, 53, (4) 206
PPh2
PPh2
O
O
PAr2
PAr2
O
O
P P
H
t-Bu
H
t-Bu
P P
t-Bu t-Bu
HH
P P
t-Bu t-Bu
HH
11 C3-TunePhos
12 C3*-TunePhos
13 TangPhos
15 BINAPINE
H
tBu
tBu
tBu
14 DuanPhos
tBu
tBu
tBu
Ar = Ph, 4-MePh,
3,5-di-tBuPh, 3,5-diMePh
or 4-MeO-3,5-di-tBuPh
16 MandyPhos 17
Me2N
Fe PPh2
Ph
PPh2
Ph
NMe2
Ru
NH2
H2
N
Ru
Ph
Ph
P
P
Ph Ph
PhPh
H
H
BH3 18
Ph
Ph
PPh2
PPh2
PPh2
PPh2
O
O
O
O
PPh2
PPh2
19 BINAP 20 H8-BINAP 21 SEGPHOS®
PPh2
PPh2
PPh2
PPh2
PPh2
PPh2
problem can be exacerbated if the alkene is notterminal. A screening exercise showed that theDiazaPhos-SPE diazaphospholane ligand system,22, was the best to prepare a bistetrahydrofuranwith good diastereoselectivity in the presence of arhodium-based catalyst, Scheme I.
Hans-Ulrich Blaser and Garrett Hoge (SolviasAG, Switzerland) gave a joint presentation. Blaserdescribed the extensive Solvias ligand families,mainly based on the ferrocene skeleton. New lig-ands that have been prepared and are currentlybeing evaluated are Kephos, 23, Fengphos, 24,Chenphos, 25, and Jospophos, 26. Hoge explainedhow Solvias performs ligand screenings and illus-trated the methodology with a number of practicalexamples including the reduction of acrylic acidsand ketones.
Professor Bernhard Breit (Albert-Ludwigs-Universität Freiburg, Germany) uses the conceptof self-assembly to prepare bisphosphine ligandsby dimerisation of monophosphines, such as 6-diphenylphosphinyl-2(1H)-pyridinone (6-DPPon),27. The dimeric ligand can be used to achieve highratios of linear products in the hydroformylationof terminal alkenes. Use of an organocatalyst such
as L-proline with an aldehyde and an alkene underhydroformylation conditions provides 1,3-diolswith good enantioselectivity. The self-assemblyconcept has been extended to chiral ligands inwhich the phosphorus moiety provides the asym-metry, such as 3-DMPICon, 28, and 3-BIPICon, 29.As with the reductions using DSM MonoPhosTM,the use of monodentate ligands allows for syner-gistic effects when two different ligands are usedin asymmetric hydrogenations.
Yongkui Sun (Merck & Co, Inc, U.S.A.)described some case studies on the use of asym-metric hydrogenations for drug synthesis atMerck. The final step in the synthesis ofsitagliptin, 30, is an asymmetric hydrogenation togive the β-amino amide. The use of a ferroceneligand has been superseded by the use of a ruthenium–DM-SEGPHOS® (SEGPHOS® withP(xyl)2 groups in place of PPh2) catalyst, with theβ-keto amide in the presence of ammonium salicylate as the amine donor. Examples of enzy-matic reactions, such as ketone reductions,
Platinum Metals Rev., 2009, 53, (4) 207
OH
O
O
OO
H
H
HO
1. Rh(CO)2(acac), Ligand
CO/H2
2. THF, HCl
(i) Rh(CO)2(acac), DiazaPhos-SPE
CO/ H2
(ii) THF, HCl
endo:exo = 10:1
α:β = 8:1
N
NP
O
O
N
NP
O
O
NH
O
Ph
O
HN
Ph
O
NH
Ph
HN
O
Ph
22 Bis(R,R,S)-DiazaPhos-SPE
Scheme IHydroformylationreaction to preparea bistetrahydrofuranin the presence of arhodium-basedcatalyst system withDiazaPhos-SPEligand
23 Kephos24 Fengphos
25 Chenphos 26 Jospophos
R2P Fe P
R2P Fe PR1
2
NMe2
PR2
Fe
PR2
P
R1
H
OFe
Fe
P
R1
NMe2
transaminations and the formation of cyanohy-drins were also given.
Professor Mikiko Sodeoka (RIKEN AdvancedScience Institute, Japan) described asymmetricreactions of metal enolates primarily based on theuse of palladium, with DM-SEGPHOS® as thechiral ligand. A wide range of reactions give highenantioselectivities including Michael, aldol,Mannich and α-fluorination reactions. For the lastclass of reactions, use of N-fluorobenzenesulfon-amide, (PhSO2)2NF, (NFSI) as the fluorinatingagent provides the best selectivity.
Concluding RemarksAs with the other meetings in this series,
NCCJapan 2009 was held just before CPhI Japan(5), allowing participants to attend both. There wassufficient time between lectures and at the banquetto allow for interaction between the participants,exhibitors and speakers. As noted above, a widevariety of methodology was covered, much associ-ated with the use of transition metal catalysis, and
in particular the use of pgm-based systems withphosphine ligands. As in the previous meetings,there was a good balance between the discovery ofnew methods and the industrial application ofexisting techniques. This conference seriesdeserves to continue to grow and prosper andProfessor Ikariya hinted that the next one mighthave the title Novel Chiral Chemistries Asia. I wishhim well with this endeavour and look forward toanother excellent meeting.
Platinum Metals Rev., 2009, 53, (4) 208
NH
Ph2P O
NH
O
P
NH
O
O
OP
R
R
27 6-DPPon
28 3-DMPICon
29 3-BIPICon (R = H)
F
F
FNH2
N
O
NN
N
30 Sitagliptin CF3
References1 Novel Chiral Chemistries Japan 2009 (NCCJapan)
Conference Programme: http://www.takasago-i.co.jp/news/2009/NCCJ2009_Program.pdf(Accessed on 27th July 2009)
2 D. J. Ager, Platinum Metals Rev., 2007, 51, (4), 1723 R. Noyori, Angew. Chem. Int. Ed., 2002, 41, (12), 20084 D. J. Ager, A. H. M. de Vries and J. G. de Vries,
Platinum Metals Rev., 2006, 50, (2), 545 CPhI Japan: http://www.cphijapan.com/eng/
(Accessed on 27th July 2009)
The ReviewerDavid Ager has a Ph.D. (University ofCambridge), and was a post-doctoralworker at the University ofSouthampton. He worked at Liverpooland Toledo (U.S.A.) universities;NutraSweet Company’s research anddevelopment group (as a MonsantoFellow), NSC Technologies, and GreatLakes Fine Chemicals (as a Fellow)responsible for developing newsynthetic methodology. David was then
a consultant on chiral and process chemistry. In 2002 he joinedDSM as the Competence Manager for homogeneous catalysis. InJanuary 2006 he became a Principal Scientist.
Early Attempts to Melt PlatinumBefore 1782 little more than a ‘partial agglomer-
ation’ of platinum had been achieved, mainly byhot forging from the powder which, although itsufficed to make many platinum artefacts, did notproduce homogeneous molten metal (1–3). Thefirst to melt impure platinum may have beenHenrik Theophil Scheffer (1710–1759) who in1751 melted platinum with copper, and laterarsenic, in a furnace (4). Franz Achard (1753–1821)similarly melted the metal with arsenic (5). In bothcases alloys of platinum, rather than pure platinum,are likely to have been melted. In 1775 PierreMacquer (1718–1784) and Antoine Baumé
(1724–1804) unsuccessfully attempted to meltplatinum in a porcelain crucible over a wood fire.Macquer and others (later including Lavoisier)then tried with burning glasses: a 56 cm diameterconcave mirror which focused the sun’s raysquickly melted iron but platinum gave only silvery-white glistening particles – the product probablycontained impurities of carbon which lowered itsmelting point (1). In 1774 a magnificent 1.2 mdiameter burning glass filled with alcohol wasmounted on a carriage and installed in the Jardinde l’Infante, Paris, France: it melted many materi-als, but not platinum (1, 6). An illustration of thisdevice is shown in Figure 1 (3).
209Platinum Metals Rev., 2009, 53, (4), 209–215
Melting the Platinum Group MetalsFROM PRIESTLEY, LAVOISIER AND THEIR CONTEMPORARIES TO MODERN METHODS
By W. P. GriffithDepartment of Chemistry, Imperial College, London SW7 2AZ, U.K.; E-mail: [email protected]
Some fifty years ago Donald McDonald wrote in Platinum Metals Review on ‘The Historyof the Melting of Platinum’ (1) and Leslie B. Hunt marked the event’s bicentenary in ‘TheFirst Real Melting of Platinum: Lavoisier’s Ultimate Success with Oxygen’(2), which is alsocovered in the invaluable “A History of Platinum and its Allied Metals” (3). The topic isrevisited and extended here, showing how oxygen, first isolated by Joseph Priestley and CarlWilhelm Scheele, was used by Antoine Lavoisier to melt platinum. Work on the melting of theother platinum group metals (pgms) and modern methods for melting the metals are alsodiscussed.
DOI: 10.1595/147106709X472507
Fig. 1 The largeburning glass built forthe Académie Royaledes Sciences and used inan early attempt to meltplatinum (3)
Priestley, Scheele and the Discoveryof Oxygen
Joseph Priestley (1733–1804) was born inFieldhead, Birstall, near Leeds in the U.K., anddied in Philadelphia, U.S.A. He was better knownin the eighteenth century for his radical religiousand political beliefs; opposition to these and hisenthusiasm for the French Revolution led him toleave the U.K. in 1794. We remember him for hisscience: photosynthesis, optics, electrostatics,biology and physiology and above all chemistry(7). He discovered many new ‘airs’ – N2O, NO,NO2, CO, SO2, NH3 and SiF4 – and investigatedHCl, SO3, Cl2, PH3 and N2. He discovered oxygenon 1st August 1774, by heating mercuric oxide(HgO) with a burning glass, and showed that itsupported combustion (8–11). He called it‘dephlogisticated air’, believing in phlogiston, thealleged principle of combustion, to the end.Phlogiston features in one of his last papers,which also describes experiments on dissolvingplatinum in aqua regia (12). In October 1774, trav-elling in France with his patron the statesmanLord Shelburne, Priestley dined with Lavoisierand told him that he had obtained ‘a new kind ofair’ by heating HgO (11).
Carl Wilhelm Scheele (1742–1786), a Swedishpharmacist for whom chemistry was a rewardinghobby, rivals Priestley in the extent of his discov-eries. He was the first to isolate chlorine (in1774), HF and HCN, and did fundamental workon NH3, HCl, compounds of Ba, Mn, Mo, Ce, Pand on several organic compounds. He madeoxygen between 1773 and 1775 by heating MnO2,KNO3, HgO, HgCO3, MgNO3 or Ag2CO3, callingit ‘vitriol air’ (aer vitrolicus) or ‘fire air’ (aer nudus);he too was a phlogistonist until he died. Hispaper on oxygen was submitted in 1775 but notpublished until 1777 (13) so Priestley did notknow of his work. Lavoisier did know, however.On 12th April 1774, he sent two copies of his“Opuscules Physique et Chimique” to Stockholm witha copy for Scheele. In September 1774 Scheelewrote thanking him and told him how to make‘fire air’ from silver carbonate and a burningglass. His letter was rather vague and Lavoisierdid not reply (14).
Lavoisier, Oxygen and the Meltingof Platinum
Antoine Lavoisier (1743–1794) is a supremefigure in chemistry, a pivotal contribution beinghis refutation of the phlogistic theory (10, 15, 16).There is some controversy as to whetherLavoisier discovered oxygen independently (10,17, 18) – he was not averse to letting people thinkthis. However, in his paper on the melting of plat-inum (19) Lavoisier did grudgingly allude toPriestley’s priority: “...cet air, que M. Priestley a décou-vert à peu-près dans la même temps que moi, & je croimême avant moi…” (…this air, which M. Priestleydiscovered about the same time as I, and I believeeven before me…) – although some of his laterpublications omit the last phrase. Unlike Priestley,however, he began to understand the real signifi-cance of oxygen. In 1778 he refers to a principeoxygine (20), and in the first edition of the 1789edition of his textbook (21) – after melting plat-inum – he refers to oxygène, from οξυζ (acide) andγενηζ (j’engendre – ‘I beget’ or ‘I generate’). Hebelieved oxygen to be an element which was aconstituent of all acids.
Lavoisier’s Melting of PlatinumPriestley never attempted to melt platinum with
‘dephlogisticated air’ but the idea did occur to hisfriend, the Reverend John Michell (1724–1793),who wrote to him that “possibly platina might bemelted by it”, recollected by Priestley in his bookof 1775 (8) which Lavoisier may have read. InApril 1782 Lavoisier directed a stream of oxygenfrom his caisse pneumatique (a storage device capableof producing a stream of hydrogen, oxygen orboth, shown in Figure 2 (3)) onto hot hollowed-out charcoal containing powdered platinum. It isnot clear from his paper whether it was solely oxy-gen or a hydrogen-oxygen mixture: he had meansof producing and storing both gases. He reportedto the Académie des Sciences on 10th April 1782,that “...le platine est fondue complètement, et les petitsgrenailles se sont reunités en un globule parfaitementrond…” (...the platinum melts completely, and theparticles united in a perfectly round globule...) (19).
On 6th June 1782, Lavoisier demonstrated hisdiscovery at the Académie to a visiting Russian
Platinum Metals Rev., 2009, 53, (4) 210
nobleman. Benjamin Franklin (1706–1790), afriend and supporter of the often pennilessPriestley, was also present, writing to Priestleythat: “Yesterday the Count du Nord was at theAcademy of Sciences, when sundry Experimentswere exhibited for his Entertainment; amongthem, one by M. Lavoisier, to show that thestrongest Fire we yet know, is made in a Charcoalblown on with dephlogisticated air. In a Heat soproduced, he melted Platina presently, the Firebeing much more powerful than that of thestrongest burning mirror” (22), Figure 3 (3).
Although neither Lavoisier, Priestley norScheele could have realised it, the ability of oxygento support combustion, a process which emits the
degree of intense heat needed to melt platinum,arises largely from the intrinsic weakness of itsO–O bond (496 kJ mol–1) (23). This weakness andconsequent facile bond cleavage arises from elec-tron lone pair-lone pair repulsions between theatoms in the O2 molecule. The heat emitted from,for example, charcoal burning in an H2-O2 mixturearises from the formation of the much strongerC=O bonds in CO2 and O–H bonds in H2Owhich are the products of combustion.
Later Methods for Melting Platinumand the Other PGMs
Lavoisier’s method was not suited to large-scaleproduction of molten platinum. In 1816 William
Platinum Metals Rev., 2009, 53, (4) 211
Fig. 2 A drawing by Madame Marie Anne Paulze Lavoisier of the apparatus designed by Lavoisier to burn continuousstreams of oxygen and hydrogen (3)
Fig. 3 The concludingparagraph of BenjaminFranklin’s letter to Priestley,dated 7th June 1782, the dayafter Lavoisier demonstrated histechnique for melting platinumat the Académie (3)
Hyde Wollaston (3) wrote to the Cambridge mineralogist Edward Clarke (1769–1822), suggest-ing that he might try to melt iridium and thenative alloy osmiridium. Clarke used a blowpipewith an H2-O2 mixture. Despite several explo-sions he melted 0.5 ounces of the metal, writingthat it melted more quickly than did lead in a fire(24). He also melted palladium, rhodium, iridi-um and native osmiridium (25). Another earlyclaim was made for melting of rhodium by a‘hydro-pneumatic blow pipe’ (26). A differentapproach was to fuse the metal by placing itbetween the poles of a large voltaic battery.John Frederic Daniell (1790–1845), using seven-ty large copper/zinc-sulfuric acid cells in series,melted platinum, rhodium, iridium and nativeosmiridium (27).
The work of Henri Sainte-Claire Deville(1818–1881) and Jules Henri Debray (1827–1888)led the way to large-scale production of moltenplatinum. Their furnace used two large hollowed-out blocks of lime containing the metal, fired by acoal gas-oxygen mixture; the refractory limeabsorbed the slag formed by oxidation of basemetal impurities. They melted a 600 g sample ofplatinum in 1856 (28, 29), and this remained themethod of choice for melting platinum untilinduction furnaces became available in the earlytwentieth century.
In 1855 George Matthey (1825–1913) visitedthe Paris Exhibition of 1855 and there metDebray, who in 1857 offered him the British rightsfor his method for melting platinum. By 1861 theprocess was in commercial use by JohnsonMatthey and Company at Hatton Garden inLondon, U.K. In 1862 Deville came to London,and with Matthey melted a huge 100 kg ingot ofplatinum. The production of platinum, in thehands of Johnson Matthey, passed from a labora-
tory procedure to a full-scale operation, makingthe metal available worldwide.
Michael Faraday (1791–1867) tried but failedto persuade Deville to demonstrate his method atthe Royal Institution of Great Britain. Instead, inone of his last discourses there, entitled ‘OnPlatinum’, Faraday demonstrated its melting byusing a ‘voltaic battery’, mentioning that “if yougo into the workshops of Mr. Matthey [you will]see them hammering and welding away [at plat-inum]…”. He noted that five of the six pgms hadbeen melted, the exception being osmium. Hewrote that ruthenium has the highest meltingpoint, followed by iridium, rhodium, platinumand finally palladium (30). Faraday also referredto platinum in his celebrated “Chemical Historyof a Candle” (31).
Melting Points of the PGMsIt was not until the late nineteenth and early
twentieth centuries that reliable pyrometers weredevised for determining melting points (32, 33).Table I lists modern values for their melting andboiling points (34); osmium has the highest valuesfor both (35).
Current Methods for Melting thePGMs
Early methods for melting the pgms used blow-pipe procedures, while Daniell used electricity.These days the same basic procedures are stillused, albeit with newer techniques.
Oxy-hydrogen or oxy-propane blowpipes ortorches are still in use for bench-scale repair ofplatinum jewellery (36, 37), and certainly tempera-tures as high as 2500ºC and probably higher canbe reached.
Three principal methods, all electrical, are cur-rently used to melt the pgms for industrial use and
Platinum Metals Rev., 2009, 53, (4) 212
Table I
Melting and Boiling Points of the Platinum Group Metals (ºC) (34, 35)
Ru Rh Pd Os Ir Pt
m.p. 2333 1963 1555 3127 ± 50 2446 1768
b.p. 4319 ± 30 3841 ± 90 2990 ± 50 5303 ± 30 4625 ± 50 3876 ± 20
for large-scale jewellery manufacture (see Figure4). Induction heating, derived from Faraday’s dis-covery in 1831 (38) of electrical induction, useshigh-frequency alternating current passed througha water-cooled copper coil surrounding a refracto-ry crucible containing the metal sample. Electronbeam heating uses a refractory cathode, oftentungsten or molybdenum: the electrons from thisare accelerated in vacuo by a high-voltage direct cur-rent source to the metal (which becomes theanode) in a refractory container, the beam beingsteered by a magnetic field. Energies developedcan reach 150 keV, and material can be melted attemperatures above 2100ºC. Finally, in arc melt-ing, which can be traced back to Humphry Davy’searly experiments with a voltaic pile, the arc isstruck under argon between a tungsten cathodeand the metal which rests on a water-cooled cop-per anode. A direct current potential of 50 V to80 V and a current of several hundred amperes iscommonly used. The technique melts tungsten
(which has a melting point of 3422ºC), and so canmelt all six pgms. These methods have been welldescribed, although without reference to pgms(39), and there is a recent history of the inductionmethod (40).
For larger quantities of platinum or palladium(1 kg to 20 kg), induction heating is the quickestand most effective procedure. The metal charge isheld in alumina or zirconia crucibles and is typi-cally melted in air since oxidation is not a problemfor these metals. Graphite or copper alloy mouldsform the ingots and the molten metal is poured byan automated procedure.
For the higher-melting iridium and rhodium,induction heating is less suitable. For these, arcmelting is used for smaller quantities, usually lessthan 1 kg, and is effected in an inert gas atmos-phere with the charge held in a water-cooledcopper alloy mould. A tungsten cathode generatesand maintains the arc, which is moved over themetal to melt and consolidate it. Electron beam
Platinum Metals Rev., 2009, 53, (4) 213
Fig. 4 Industrial casting of molten platinum.Image courtesy of Johnson Matthey NobleMetals
melting is used to make larger ingots: an evacuat-ed chamber is used under a vacuum in excess of10–4 Torr, with the metal held in water-cooledcopper alloy moulds as for arc melting. As withthe latter technique, several melting sequences arerequired with the ingot being turned over severaltimes to ensure complete and even melting. Ingotsizes are typically between 2 kg and 15 kg (41).There is a recent paper in this Journal providinginformation on the melting of iridium (42).
ConclusionsThe discovery and production of gaseous oxy-
gen, by Scheele and Priestley, allowed the firstmelting of pure platinum by Lavoisier in the late
18th century. The other platinum group metalswere melted during the early 19th century, and bythe mid-19th century commercial-scale productionof platinum had become possible for the first time.The methods developed during this periodremained in use until the early 20th century, whenmodern methods of industrial scale productionusing electrical heating became possible.
Acknowledgements I am grateful to the editorial and technical staff
of Johnson Matthey for information on modernprocedures for melting the pgms, and to Dr MaxWhitby, Imperial College London, U.K., for gen-eral advice on these aspects.
Platinum Metals Rev., 2009, 53, (4) 214
1 D. McDonald, Platinum Metals Rev., 1958, 2, (2), 552 L. B. Hunt, Platinum Metals Rev., 1982, 26, (2), 793 D. McDonald and L. B. Hunt, “A History of Platinum
and its Allied Metals”, Johnson Matthey, London,U.K., 1982
4 H. T. Scheffer, Kungl. Vetensk. Akad. Handl., 1752, 13,269–276
5 F. K. Achard, Nouv. Mém. Acad. R. Sci. Berlin, 1781, 12,103
6 J. C. P. Trudaine de Montigny, P. J. Macquer, L. C.Cadet, A. Lavoisier and M. J. Brisson, Mém. Acad. R.Sci., 1774, 88, 62
7 “Joseph Priestley: A Celebration of His Life andLegacy”, eds. J. Birch and J. Lee, The Priestley Society,Birstall, South Yorkshire, U.K., 2007
8 J. Priestley, “The Discovery of Oxygen, Part 1”,Experiments by Joseph Priestly, LL.D. (1775);Alembic Club Reprints, No. 7, W. F. Clay, Edinburgh,1894, p. 8
9 W. P. Griffith, Notes Rec. R. Soc. Lond., 1983, 38, (1),1
10 W. H. Brock, “The Fontana History of Chemistry”,Fontana Press, London, U.K., 1992, 744 pp
11 J. Priestley, “The Doctrine of Phlogiston Established,and That of the Composition of Water Refuted”, 2ndEdn., Printed by Andrew Kennedy for P. Byrne,Philadelphia, U.S.A., 1803
12 J. Priestley, Trans. Am. Phil. Soc., 1802, 4, 113 C. W. Scheele, “Chemische Abhandlung von der Luft
und dem Feuer”, M. Swederus, Upsala and Leipzig,1777; ‘Chemical Treatise on Air and Fire’ in L. Dobbin(translated into English), “Collected Papers of CarlWilhelm Scheele”, G. Bell & Sons, Ltd, London, 1931;See also Alembic Club Reprints, No. 8, The AlembicClub, Edinburgh, 1906
14 U. Bocklund, ‘A Lost Letter from Scheele to Lavoisier’,Lychnos, 1957–58, 39
15 A. Lavoisier, Mém. Acad. R. Sci., 1775, 429 (issued in1778); Reprinted in “Œuvres de Lavoisier”, ImprimerieImpériale, Paris, 1862, Vol. 2, p. 122
16 A. Lavoisier, Mém. Acad. R. Sci., 1783, 505 (issued in1786); Reprinted in “Œuvres de Lavoisier”, ImprimerieImpériale, Paris, 1862, Vol. 2, p. 623
17 J. Priestley, “Experiments and Observations onDifferent Kinds of Air”, 2nd Edn., Printed for J.Johnson, London, U.K., 1784, Vol. 2, p. 34
18 S. J. French, J. Chem. Educ., 1950, 27, 83 19 A. Lavoisier, Mém. Acad. R. Sci., 1782, 457 (issued in
1785); Reprinted in “Œuvres de Lavoisier”, ImprimerieImpériale, Paris, France, 1862, Vol. 2, p. 423
20 A. Lavoisier, Mém. Acad. R. Sci., 1778, 535 (issued in1781); Reprinted in “Œuvres de Lavoisier”, ImprimerieImpériale, Paris, France, 1862, Vol. 2, p. 248
21 A. Lavoisier, “Traité Eléméntaire de Chimie”, 1st Edn.,Cuchet, Paris, France, 1789, Vol. 1, p. 48
22 “The Writings of Benjamin Franklin”, ed. A. H. Smyth,in 10 volumes, Macmillan, London, U.K., 1906, Vol.VIII, p. 453
23 H. M. Weiss, J. Chem. Educ., 2008, 85, (9), 121824 E. D. Clarke, Thomson’s Ann. Philos., 1817, 9, 8925 E. D. Clarke, “The Gas Blow-Pipe or, Art of Fusion
by Burning the Gaseous Constituents of Water”,printed by R. Watts for Cadell & Davies, London, 1819
26 J. Cloud, Trans. Am. Phil. Soc., 1818, 1, 16127 J. F. Daniell, Phil. Trans. R. Soc. Lond., 1839, 129, 8928 H. Sainte-Claire Deville, Ann. Chim. Phys., 1856, 46,
(3), 18229 H. Sainte-Claire Deville and H. J. Debray, Comptes
Rendus Acad. Sci., Paris, 1857, 44, 1101
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Chemical History of a Candle: to Which is Added aLecture on Platinum”, ed. W. Crookes, Griffin, Bohn,and Company, London, U.K., 1861, p. 173
32 H. L. Callendar, Philos. Mag., 1899, 47, 19133 Circular of the National Bureau of Standards, No. 7,
U.S. Department of Commerce, Washington, D.C.,U.S.A., 1910
34 J. W. Arblaster, Platinum Metals Rev., 2007, 51, (3), 13035 J. W. Arblaster, Platinum Metals Rev., 2005, 49, (4), 16636 Platinum Guild International, Technical Articles:
http://www.platinumguild.com/output/Page2414.asp
(Accessed on 21st July 2009)37 Platinum Guild International, Technical Videos:
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38 M. Faraday, Phil. Trans. R. Soc. Lond., 1832, 122, 12539 A. C. Metaxas, “Foundations of Electroheat: A Unified
Approach”, John Wiley & Sons, Chichester, U.K.,1996
40 A. Mühlbauer, “History of Induction Heating andMelting”, Vulkan Verlag, Essen, Germany, 2008
41 Johnson Matthey Noble Metals, Private communication,20th March 2009
42 E. K. Ohriner, Platinum Metals Rev., 2008, 52, (3), 186
Platinum Metals Rev., 2009, 53, (4) 215
The AuthorBill Griffith is an Emeritus Professor ofChemistry at Imperial College, London,U.K. He has much experience with theplatinum group metals, particularlyruthenium and osmium. He haspublished over 270 research papers,many describing complexes of thesemetals as catalysts for specific organicoxidations. He has written seven bookson the platinum metals, and is
currently writing another on oxidation catalysis by rutheniumcomplexes. He is the Secretary of the Historical Group of theRoyal Society of Chemistry.
216
The need to move towards a low carbon econo-my has led to unprecedented interest in renewableenergy sources, including solar power. One type ofsolar cell, the dye sensitised solar cell (DSSC), firstreported in 1991 by Michael Grätzel and coworkersat the Ecole Polytechnique Fédérale de Lausanne(1), is a photoelectrochemical device which con-tains ruthenium in the photoanode and platinum inthe counter electrode. It therefore representsanother example of a platinum group metal-basedsustainable technology. In this review, DSSC tech-nology is briefly discussed to provide some contextfor selected examples of recent patent activity.
BackgroundHistorically, conventional solar cells have relied
on a solid semiconductor to perform the dual func-tion of light absorption and charge conduction,imposing strict requirements on the compositionand purity of materials used (2). DSSCs, by contrast, use a monolayer of photosensitive ruthe-nium-based dye adsorbed on a thin layer ofnanocrystalline titanium dioxide (TiO2) to harvestlight and, as a result, have comparatively low manufacturing costs. They can take the form ofthin, flexible and transparent sheets, making themuseful in applications such as building-integratedpower sources (3). Furthermore, they performeffectively in dim and diffuse light (1), allowing foruse indoors and in mobile electronic devices.
These advantages largely offset the lower effi-ciency of DSSCs, which stands at a record of 10%to 11% (3–5) – significantly lower than the 15% to18% achieved by the widely-used polycrystallinesilicon cell (6). Efforts are continually being under-taken to improve the efficiency and hence thecompetitiveness of the technology.
Overall cell efficiency is subject to a number offactors, but fundamental considerations relating tothe dye are: firstly, how efficiently the moleculesabsorb incident photons; secondly, how efficientlythese photons are converted to electron-hole pairs;
and thirdly, how effectively charge separation andcollection occurs (2). The most efficient DSSCsdemonstrated to date have all been based on ruthe-nium dyes developed by the Grätzel group: the N3,N719 and ‘black’ dyes (4) (Figure 1 (4, 7)). As wellas superior light harvesting properties and durabili-ty, a considerable advantage of these dyes lies in themetal-ligand charge transfer (MLCT) transition,through which the photoelectric charge is injectedinto the TiO2. For these ruthenium complexes, thistransfer takes place at a much faster rate than theback reaction, in which the electron recombineswith the oxidised dye molecule rather than flowingthrough the circuit and performing work (2).
Conversion efficiency of absorbed photons isalso very high, and offers little room for improve-ment (2, 8). Therefore, continued research effortsare largely focused on improving the absorptionof incident light. This can be achieved by manip-ulating the dye’s molecular structure to eitherincrease the degree of absorption of photons inthe functional wavelength range (as measured bythe molar extinction coefficient, ε), or to extendthe functional range – ideally, to within the nearinfrared (N-IR) region (9). Here, we have selectedthree patents, all claiming novel ruthenium com-plexes for application to DSSCs, to demonstratestrategies currently being investigated in this area.
Novel Ruthenium Dye ComplexesThe first example, filed by Dongjin Semichem
Co, Ltd, South Korea (7), claims a number of newcomplexes based on the N3 structure. The struc-ture has been altered by replacing one or both ofthe COOH groups on at least one of the bipyridylligands with a range of more highly π-conjugatedmoieties. The absorption spectra of six examples ofthe new complexes are presented, and the values ofε for three of the new dyes indicate a significantimprovement in absorption: in one embodiment ε = 22,640 M–1 cm–1 at 533 nm, compared to valuesof between 14,000 M–1 cm–1 and 15,000 M–1 cm–1 for
Platinum Metals Rev., 2009, 53, (4), 216–218
Progress in Ruthenium Complexes forDye Sensitised Solar Cells
DOI: 10.1595/147106709X475315 PGM HIGHLIGHTS
N3 and N719 at ~ 535 nm (8, 10). In two otherembodiments, ε values of ~ 21,000 M–1 cm–1 to22,500 M–1 cm–1 are achieved at wavelengths longerthan 550 nm, indicating a shift towards longerwavelengths. These improvements do not appearto translate into increased cell efficiency and valuesgiven for short-circuit current density (Jsc) andopen circuit voltage (Voc) are lower than for theestablished dye. However, an interesting point tonote is the possibility of using a combination ofdyes, an approach which may allow greater flexibil-ity in optimising both absorption and range.
An application filed by Turkiye Sise ve CamFabrikalari AS, Turkey (11), aims in one embodi-
ment to increase ε through extended π-conjugationand a double core. A ruthenium dimer structure isclaimed, designated K20 (Figure 2) and described ashaving ε = 22,000 M–1 cm–1. The wavelength at whichthis measurement is taken is not given, although else-where the authors show that the longest-wavelengthabsorption peak occurs at 520 nm. This ε value isagain higher than values for N3 and N719 at similarwavelengths. Overall efficiency is also good, beingcomparable to the existing dyes.
The technique of increasing conjugationthrough the use of larger and more complex lig-ands is again demonstrated by a patent granted in2009 to inventors from Everlight Chemical
Platinum Metals Rev., 2009, 53, (4) 217
Ru
NN
C
S C
S
N
N
N
N
HOOC
COOH
COOH
COOH
N3 dye
Ru
NN
C
S C
S
N N
N
TBAOOC
COOH
COOTBA
N
C
S
Black dye
Ru
NN
C
S C
S
N
N
N
N
HOOC
COOTBA
COOH
COOTBA
N719 dye
Fig. 1 Structures of the ruthenium-based dyes N3, N719 and ‘black dye’ developed by the Grätzel group (4, 7)
Fig. 2 Structure of a novel ruthenium dimer dye complex (11)
Ru
NN
C
S C
S
N
N
N
HOOC
COOH
Ru
N
C
S
N
N
N
N
COOH
COOH
C
S
N
N
N
H3C
H3C
N
CH3
CH3
K20
TBA = tetrabutylammonium cation
Industrial Corp (U.S.A.) and Academia Sinica inTaiwan (12). The complexes claimed here are alsobased on N3, with one of the ligands modified toa structure with additional aromatic rings and, insome embodiments, containing alkyl chains. Theinventors present the results of comparative testsof one of the complexes (shown in Figure 3)against N719: at the longest peak wavelength (~ 530 nm), ε is increased to 14,007 M–1 cm–1
(from 12,617 M–1 cm–1 quoted for N719) and aslight redshift in the absorption spectrum is seen.The values claimed for Jsc and Voc are very similarto those achieved using N719, and the overall cellefficiency is also comparable to the existing dyes.
Concluding RemarksIt is clear that research into dyes for DSSCs is
progressing and new ruthenium-based structurescontinue to be reported. Although alternative dyeshave been developed, including non-metal organ-ic dyes (13) and dyes based on iron and zinc (14,15), these have so far proved inferior to the ruthe-nium dyes (4). Dyes formulated from platinumand iridium complexes are also showing somepromise (16, 17), but this research is still in theearly stages. With this in mind, the most promis-ing current strategy is to increase the efficiency oflight absorption at the molecular level by modify-ing or enhancing the established ruthenium-baseddyes, which still hold their place at the forefront ofthe technology. The improved light absorption
achieved in the patents discussed here holdspromise for increased cell efficiency, which maybe realised with further refinements. With DSSCsnow at the pilot scale and seeing increasing commercial investment (18–21), developments inthis area will be watched with interest.
M. RYAN
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18 Dyesol: http://www.dyesol.com/19 G24 Innovations: http://www.g24i.com/20 3GSolar Ltd, Solar Energy Modules: http://3gsolar.com/21 Solaronix SA: http://www.solaronix.com/
Platinum Metals Rev., 2009, 53, (4) 218
Ru
NN
C
S C
S
N
N
N
N
HOOC
COOH
Fig. 3 A modified complex based on the ruthenium dyeN3 (12)
“PEM Fuel Cell Electrocatalysts and CatalystLayers: Fundamentals and Applications”, edited byJiujun Zhang, is an excellent book. The editor is anexperienced electrochemist with twenty-four yearsof experience, nine in fuel cells, and is theTechnical Leader in Catalysis at the NationalResearch Council Institute for Fuel Cell Innovationin Canada. Zhang states in his introduction that acomprehensive and in-depth book that focuses onboth fundamental and application aspects of polymer electrolyte membrane (PEM) fuel cellelectrocatalysts and catalyst layers is definitelyneeded. I agree, PEM fuel cells have made majoradvances in recent years, and have begun to entertheir eagerly-anticipated commercialisation phase(1). However, this has brought new challenges,requiring electrochemists to work much moreclosely with engineers to optimise systems for specific applications. Therefore I read this bookeagerly, hoping that the authors had managed towrite a fundamental electrochemistry book thatwas readable by an informed engineer. I believethey have succeeded in this, and in this shortreview I have discussed a few key points whichshould illustrate this.
The book is split into useful chapters, a numberof them identifying and discussing mitigationstrategies for some of the most significant barriersremaining to the wider adoption of PEM fuel cells, such as Chapter 17 on ‘Reversal-tolerantCatalyst Layers’. Other chapters introduce more fundamental electrochemical concepts such asadsorption, activation energies and thermodynam-
ics, which are discussed in Chapter 5, ‘Applicationof First Principles Methods in the Study of FuelCell Air-Cathode Electrocatalysis’.
The level of thoroughness and detail is alsoimpressive: for example, Chapter 16 on ‘CO-toler-ant Catalysts’ alone has almost 450 references. Thischapter describes both the fundamental conceptsand reaction mechanisms necessary to understandthe problem of carbon monoxide ‘poisoning’ offuel cell catalysts – in particular the bifunctionalmechanism of carbon monoxide tolerance exhib-ited by platinum-ruthenium alloy catalysts, whereruthenium provides the ability to generatehydroxyl species to oxidise CO at lower potentials(2). The chapter then goes on to discuss the devel-opment of other carbon monoxide-tolerantcatalysts, describing the vast array of mostly plat-inum-based catalysts that have been developedover the last thirty to forty years (3, 4). Crucially,each chapter ends in a brief but useful conclusionwhich identifies the avenues of research where weshould anticipate future breakthroughs. The refer-ences are conveniently located at the end of eachchapter, making them easy to access. Each chaptercan be read as a stand-alone piece.
The book claims to be aimed at the broader fuelcell community, including engineers, industryresearchers and students. I would agree with thisclaim, but with the small caveat that I would notrecommend it to a total novice, as the level ofdetail would rapidly become overwhelming forsomeone not familiar with the language and concepts associated with fuel cells and electro-
219Platinum Metals Rev., 2009, 53, (4), 219–220
“PEM Fuel Cell Electrocatalysts andCatalyst Layers: Fundamentals andApplications”EDITED BY J. ZHANG (NRC Institute for Fuel Cell Innovation, Canada), Springer-Verlag London Ltd, Guildford, Surrey, U.K., 2008,
1137 pages, ISBN 978-1-84800-935-6, £121.50, €134.95, U.S.$209.00 (Print version); e-ISBN 978-1-84800-936-3,
DOI: 10.1007/978-1-84800-936-3 (Online version)
Reviewed by Gregory J. OfferDepartment of Earth Science and Engineering, South Kensington Campus, Imperial College, London SW7 2AZ, U.K.;
E-mail: [email protected]
DOI: 10.1595/147106709X474361
chemistry. The book is clearly up to date and rep-resents a considerable amount of work by theauthors, who all appear well qualified to writetheir respective chapters. The subject area of eachchapter would merit an entire book in that fieldalone – but these exist already, and the value hereis in linking the subject areas together so that the reader can benefit from having them all in one volume. The end result is rather long at over 1100pages, but this is necessary and not a criticism,and represents good value considering the listprice.
For the reader who is interested in platinumgroup metals (pgms) this book contains plenty ofinformation. Nearly every chapter discusses anarea that is dominated by the electrochemistry ofplatinum and other pgms, but this is not surprisingconsidering the central role of platinum in PEMfuel cell catalysis. From this point of view, thebook also provides a good review of current tech-nology and does not appear to make any majoromissions of information that the pgm catalystspecialist would be expecting to see.
On the whole I got a very positive impressionof this book, and feel that it does succeed in itsaims. It is well written and sufficiently consistentin style considering its multiple authors, and theeditor has done a good job of pulling together somany topics and presenting them as a coherentwhole. The book would be a good purchase for
anyone who has an interest in the science of PEMfuel cells. If you are new to the field, perhaps anundergraduate, there are probably better books tostart with (see for example (5)). However, if youare a scientist or engineer, either at the top of yourfield or with just a year or more of experience inelectrochemistry and/or electrocatalysis, this is aworthy addition to your book collection.
Platinum Metals Rev., 2009, 53, (4) 220
The ReviewerDr Gregory Offer is a Research Associate inFuel Cell Science and Engineering, within theFaculty of Engineering at Imperial College,London, U.K., working with both theDepartment of Earth Science Engineering andthe Department of Materials. He is also projectmanager of Imperial Racing Green, anundergraduate teaching project buildinghydrogen-powered fuel cell hybrid vehicles.
He is currently on secondment to the Energy and Climate ChangeCommittee at the Houses of Parliament in London, U.K.
References1 “Fuel Cells: Commercialisation”, Fuel Cell Today,
U.K., 2008:http://www.fuelcelltoday.com/events/industry-review(Accessed on 14th August 2009)
2 A. R. Kucernak and G. J. Offer, Phys. Chem. Chem. Phys.,2008, 10, (25), 3699
3 O. A. Petry, B. I. Podlovchenko, A. N. Frumkin andH. Lal, J. Electroanal. Chem., 1965, 10, (4), 253
4 J. S. Spendelow, P. K. Babu and A. Wieckowski, Curr.Opinion Solid State Mater. Sci., 2005, 9, (1–2), 37
5 R. O’Hayre, S.-W. Cha, W. Colella and F. B. Prinz,“Fuel Cell Fundamentals”, 2nd Edn., John Wiley &Sons, Inc, New York, U.S.A., 2009, 576 pp
221
The Taylor Conferences are organised by theSurface Reactivity and Catalysis (SURCAT) Groupof the Royal Society of Chemistry in the U.K. (1).The series began in 1996, to provide a forum fordiscussion of the current issues in heterogeneouscatalysis and, equally importantly, to promoteinterest in this field among recent graduates. Thefourth in the series was held at Cardiff Universityin the U.K. from 22nd to 25th June 2009, attract-ing 120 delegates, mainly from U.K. academiccentres specialising in catalysis. Abstracts of all lec-tures given at the conference are available on theconference website (2). The first half of the confer-ence consisted of presentations by establishedresearchers from the U.K., Japan and the U.S.A.,with each presentation afforded ample time fordebate and discussion. The format of the secondhalf was similar, but with a key difference: the pre-senters were some of the postgraduate studentsand postdoctoral researchers who, it is hoped, willbecome the future generation of catalysis experts.
Concepts, Theories and MethodologyProfessor Sir Hugh Taylor, after whom the
Taylor conferences are named, was a pioneer inthe study of chemisorption and catalysis on metalsand metal oxides (3). As Professor Frank Stone(Emeritus Professor of Chemistry, University ofBath, U.K.) reminded us in his opening address, H. S. Taylor (as he was known in his time) wasresponsible for introducing the concepts of acti-vated adsorption and of the active site, both ofwhich were highly controversial when he first proposed them around 1930 (4), but which havebecome fundamental to our understanding ofmany catalytic phenomena.
Professor Gabor Somorjai (University ofCalifornia, Berkeley, U.S.A.) developed the themethat progress in catalysis is stimulated by revolu-tionary changes in thinking. He predicted that,whereas in previous eras new catalysts were identi-fied through an Edisonian approach (based on trialand error) or discovered on the basis of empiricalunderstanding, future catalyst design will be basedon the principles of nanoscience. He highlighted hisidea of ‘hot electrons’ that are ejected from a metalby the heat of reaction produced at active sites, butwhich could become a potential energy source ifthey were generated by the absorption of light.
As described by Professor Richard Catlow(University College London, U.K.) and StephenJenkins (University of Cambridge, U.K.), quantummechanical techniques for modelling many-electron systems lend themselves to the study ofcatalytic materials and catalytic reaction pathways.Professor Catlow’s particular expertise lies in thestudy of defective metal oxides, and the way inwhich they interact with metal particles. In the caseof palladium deposited on ceria, his models predictan increase in the concentration of Ce3+ speciesresulting from electron transfer from the metal tothe metal oxide. Jenkins has been examining thelikelihood of specific reaction steps taking place onthe surface of supported metal catalysts. For bothalkane synthesis and combustion, his calculationsimplicate a common formyl intermediate, which isnot readily detected by spectroscopic techniques.However, Professor Charles Campbell (Universityof Washington, U.S.A.) cautioned against an over-reliance on surface modelling. Based on classicalmicrocalorimetric measurements, he has shownthat density functional theory (DFT) underpredicts
Platinum Metals Rev., 2009, 53, (4), 221–225
The Taylor Conference 2009CONVERGENCE BETWEEN RESEARCH AND INNOVATION IN CATALYSIS
Reviewed by S. E. Golunski§ and A. P. E. York*‡
Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9NH, U.K.;
and ‡Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street,
Cambridge CB2 3RA, U.K.; *E-mail: [email protected]
DOI: 10.1595/147106709X474307
§Present address: Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K.
the heat of adsorption for a variety of molecules(for example, carbon monoxide, cyclohexene andaromatics) on a range of surfaces (such as carbon,precious metals or metal oxides).
Taking a View Professor Lynn Gladden (University of
Cambridge) described how macroscopic andmicroscopic events can be tracked in an opticallyopaque system, such as a catalytic reactor. Usingmagnetic resonance imaging (MRI) – essentially thesame technique as used diagnostically in medicine –she has been able to observe the liquid flow fieldsthat develop in packed bed reactors. By combiningthe images with measurements from temperaturesensors, detailed reaction profiles can be producedfor steady-state and dynamic operating conditions.
On a different scale, Professor Chris Kiely(Lehigh University, U.S.A.) has used dark-fieldimaging techniques to detect the smallest metallic,bimetallic and metal oxide particles (less than 1 nmin diameter) by electron microscopy. In what maybecome a seminal study, he has correlated the highCO-oxidation activity of a specific gold/iron oxide(Au/Fe2O3) catalyst with the presence of two-layer, 0.5 nm-diameter gold clusters.
The importance of studying catalysis over arange of scales was emphasised by ProfessorTrevor Rayment (Diamond Light Source Ltd,U.K.). The new U.K. synchrotron light source isintended to provide understanding of ‘real catalysts, under real conditions, in real time’ (5).One of the ambitions is to increase the through-put for techniques such as X-ray absorptionspectroscopy, by reducing the amount of non-productive beam time. Although the Diamondfacilities are not expected to provide the tools forcatalyst discovery, it is hoped that they can accel-erate the development process by identifying thecritical relationships between catalyst structureand performance.
Controlling SelectivityStressing a point made by Professor Somorjai
that catalysis in the 21st century is all about selec-tivity, Chris Baddeley (University of St Andrews,U.K.) and Professor Andrew Gellman (Carnegie
Mellon University, U.S.A.) separately describedthe complex dependence of enantioselective reac-tions on surface composition and structure. As explained by Professor James Anderson(University of Aberdeen, U.K.), in the context ofalkyne hydrogenation, poor selectivity is often theresult of heterogeneity in the exposed sites, evenon apparently clean and compositionally homoge-neous surfaces. Through targeted use of additives,such as bismuth in the case of palladium-basedhydrogenation catalysts, specific non-selectivesites can be deliberately blocked.
During the direct synthesis of hydrogen perox-ide from hydrogen and oxygen, the combustion ofhydrogen and the over-hydrogenation of hydrogenperoxide to water need to be suppressed.Professor Graham Hutchings (Cardiff University,U.K.) has shown that gold-palladium catalysts areamong the most effective, but their performancecan be sensitive to the support material used. Incollaboration with Professor Kiely, he has foundthat the nature of the dispersed gold-palladium canvary, with core-shell particles (on titania and alumina) producing lower yields of H2O2 than palladium-rich alloy particles (on carbon). Bothtypes of core-shell particle, those with a gold coreand palladium shell and those with a palladium coreand gold shell, were less active than the palladium-gold alloy.
Professor Masatake Haruta (Tokyo Metropoli-tan University, Japan) has found that small goldclusters can selectively catalyse some particularlychallenging reactions. The outstanding example isthe selective insertion of oxygen into propylene toform propylene oxide, which is currently producedby indirect processes that produce large quantitiesof waste byproducts. By reactively grinding a non-chloride Au(III) precursor with titanium silicalite(TS-1), Professor Haruta has dispersed the gold as1.6 nm particles, which can activate propylene toreact with O–O–H species formed from oxygenand water at the metal-support interface.
Promoting and Maintaining ActivityVanadia supported on θ-alumina is one of the
best catalysts for butane dehydrogenation, but therate of reaction is very sensitive to the vanadia
Platinum Metals Rev., 2009, 53, (4) 222
loading. Professor David Jackson (University ofGlasgow, U.K.) reported that maximum activitycoincides with the presence of a mainly polymericform of vanadate species which covers most of thealumina surface. However, another key perfor-mance criterion is durability. During butanedehydrogenation, two forms of deactivation canbe discerned: a short-term but reversible effectcaused by deposition of carbon-rich species onthe catalyst surface, and a longer-term effect asso-ciated with an irreversible phase change in thealumina.
In the Francois Gault Lecture, ProfessorRobbie Burch (Queen’s University Belfast, U.K.)explained the challenges faced in developing andstudying catalyst technology for removing nitro-gen oxides (NOx) from diesel exhaust. Focusingon the use of silver for NOx reduction by directreaction with some of the diesel fuel, he showedthat its performance can be dramatically improvedby the addition of hydrogen. As described in a presentation by Stan Golunski (Johnson MattheyTechnology Centre, Sonning Common, U.K.) thehydrogen can be generated in situ through aprocess of exhaust gas reforming using a rhodiumcatalyst. Professor Burch explained how X-rayabsorption fine structure (EXAFS) studies of silver have been used to refute one of the pro-posed roles of hydrogen, as a structural modifier,implying instead that it is directly involved in theNOx-reduction mechanism. Although severalspectroscopic studies have been published (6)showing the presence of cyanide and isocyanateon the silver surface when hydrogen is present,kinetic measurements at Queen’s University Belfasthave ruled these out as reactive intermediates, suggesting that more transitory species (such ashydroxamic acid or ammonia) are involved.
Future ProspectsDuring his introduction to the postgraduate
student and postdoctoral researcher presentations,Jack Frost (Johnson Matthey Fuel Cells, U.K.)compared and contrasted the academic process ofresearch with the industrial activity of innovation.He used the example of vehicle emission controlto show how the pressing need for improved local
air quality led to the development of technologyfor catalytic aftertreatment using pgm catalysts (7).This highly effective technology does not, howev-er, address the global problem of greenhouse gasemissions, which is now the prime motivator forthe introduction of fuel cells.
Appropriately, there was an environmentaltheme running through many of the presentationsin this section of the conference. For example, COoxidation was covered by SankaranarayananNagarajan (National Chemical Laboratory, Pune,India), who looked at oxygen mobility and the roleof subsurface oxygen on palladium surfaces (8, 9),Figure 1. The subject was also covered by KevinMorgan (Queen’s University Belfast), who present-ed a temporal analysis of products (TAP) studyshowing that the addition of gold to CuMnOx
results in the availability of more surface oxygenand promotion of the Mars-van Krevelen oxygentransfer mechanism.
A number of researchers from CardiffUniversity presented work on selective oxidationreactions. For example, Jonathan Counsell has beenstudying the effect of adding gold to a supportedpalladium acetoxylation catalyst. He has foundthat the gold suppresses carbon formation on thepalladium surface by preventing dehydrogenation.Kara Howard described her work on modellingoxygen dissociation on gold clusters supported on iron oxide, and showed that the iron oxide stabilises dissociated oxygen atoms. DyfanEdwards presented a surface science study of thesynergy between the individual metal oxides iniron molybdate catalysts, which are used for oxi-dising methanol to formaldehyde. The selectivityof iron oxide changes with the level of coverageby molybdenum, from total combustion when nomolybdenum is present, to partial oxidation (toCO) at low coverage, and finally selective oxida-tion (via a methoxy intermediate) at high coverage.Dr Jennifer Edwards has been examining theeffect of preparation and pretreatment variableson the performance of gold-palladium catalystsfor the direct synthesis of hydrogen peroxide.Acid pretreatment of the support material hasresulted in catalysts with lower activity for theunwanted consecutive hydrogen peroxide-hydro-
Platinum Metals Rev., 2009, 53, (4) 223
genation reaction, leading to very impressivehydrogen peroxide yields.
The influence of the iron:cobalt ratio in anFe2O3-Co3O4 catalyst, for converting ethanol tohydrogen, has been studied by Abel Abdelkader(Queen’s University Belfast). Fe2O3 catalysesethanol steam reforming, and Co3O4 the water-gasshift reaction, so that a 1:1 ratio produces the opti-mum yield. In the field of syngas and hydrogenutilisation, Poobalasuntharam Iyngaran (Universityof Cambridge) presented a study of the effect ofpotassium promoters on ammonia synthesis overiron, which showed that stepwise hydrogenationof nitrogen surface adatoms is unaffected by thepresence of potassium. Sharon Booyens (CardiffUniversity) is interested in DFT modelling of COadsorption on iron surfaces, in the context ofFischer-Tropsch catalysis. The models predictthat surface carbon causes a weakening of theFe–CO interaction, and therefore CO dissociationbecomes less favourable. Andrew McFarlane(University of Glasgow) presented his work on C5 olefin hydrogenation over 1% Pd/Al2O3. Hesuggested that reaction of the cis-pentene isomermust proceed via formation of the trans isomerbefore hydrogenation can occur.
Finally, there were several very topical presenta-tions concerned with clean synthesis of chemicalsand fuels. Lee Dingwall (University of York, U.K.)has been synthesising and working with a bifunc-tional heterogeneous catalyst that combines anactive ruthenium organometallic centre with apolyoxometallate cage, Figure 2. This provides acidsites and also confers great stability, and the cata-lyst structure displays high activity for C–C bondformation. Ceri Hammond (Cardiff University)described the reaction of glycerol with urea overzinc, gallium or gold supported on zeolite.Glycerol carbonate can be obtained with highselectivity in a one-step solvent-free process overthese catalysts, though there is some question overtheir stability.
The prize for the best student presentation wasawarded to Janine Montero (University of York)who is researching the use of heterogeneous catalysts for biodiesel synthesis by transesterifica-tion, as a replacement for the liquid catalystscurrently in use. She has shown, by Auger electronspectroscopy, that high-temperature calcination of nanoparticulate magnesium oxide results inincreased surface polarisability, and therefore higherLewis basicity. Her results show that there is a
Platinum Metals Rev., 2009, 53, (4) 224
Fig. 1 Schematic model for oxygen diffusion followed by CO + O2 reaction on Pd(111) > 550 K. Pdδ+= mildly oxidised Pd(Courtesy of Chinnakonda S. Gopinath, National Chemical Laboratory, Pune, India)
CO
O2
4
6
2
CO2
1
5
3
Pd(111)
Pdδδ+(111)
Pdδδ+(111)
Pd(111)
Pdδδ+(111)
Pdδδ+(111)
linear relationship between polarisability and trans-esterification activity over these MgO catalysts.
SummaryIn summing up the conference, Professor
Wyn Roberts (Emeritus Professor, CardiffUniversity) recalled that when he began his Ph.D.he had to make the choice between studyingclean surfaces (i.e. single crystals) or real catalysts.As many of the presentations highlighted, thisdistinction is no longer useful, with the so-called‘material’ and ‘pressure’ gaps in catalysis, betweenresults obtained from surface science studies,usually using idealised surfaces under high
vacuum, and those from real catalyst materials atambient or high pressures (10), having graduallynarrowed. Frost had earlier commented on a sim-ilar convergence, between research andinnovation. As he pointed out, though, theseactivities need to remain distinct, because theyfulfil quite different functions. However, withtheir shared values of insight, integrity, creativityand professionalism, they will be increasinglydirected in parallel at our most urgent challengesin catalysis and in society: sustainability and envi-ronmental protection.
The fifth Taylor Conference is scheduled totake place in Aberdeen in 2013 (11).
Platinum Metals Rev., 2009, 53, (4) 225
+ -
HNEt 3
HNEt3
P
Ru C
P
WO
Fig. 2 Proposed structure of thepolyoxometallate-tethered rutheniumcomplex [HNEt3]+[(Ru{η5-C5H5}{PPh3}2)2(PW12O40)]–(Courtesy of Karen Wilson, University ofYork, U.K.)
1 Royal Society of Chemistry, Surface Reactivity andCatalysis (SURCAT) Group: http://www.rsc.org/Membership/Networking/InterestGroups/SurfaceReactivity/index.asp (Accessed on 5th August 2009)
2 The Taylor Conference 2009: http://www.taylor.cf.ac.uk/ (Accessed on 5th August 2009)
3 E. R. Rideal and H. S. Taylor, “Catalysis in Theory andPractice”, Macmillan and Co Ltd, London, U.K., 1919
4 P. B. Weisz, Microporous Mesoporous Mater., 2000, 35–36,1
5 Diamond Light Source, Publications, Case Studies:http://www.diamond.ac.uk/Home/Publications/case_studies.html (Accessed on 27th August 2009)
6 F. Thibault-Starzyk, E. Seguin, S. Thomas, M. Daturi,H. Arnolds and D. A. King, Science, 2009, 324, (5930),1048
7 M. V. Twigg, Appl. Catal. B: Environ., 2007, 70, (1–4),2
8 C. S. Gopinath, K. Thirunavukkarasu and S. Nagarajan,Chem. Asian J., 2009, 4, (1), 74
9 S. Nagarajan, K. Thirunavukkarasu and C. S. Gopinath,J. Phys. Chem. C, 2009, 113, (17), 7385
10 J. M. Thomas, J. Chem. Phys., 2008, 128, (18), 18250211 Royal Society of Chemistry, Publishing, Journals,
PCCP, News, 2009: http://www.rsc.org/Publishing/Journals/CP/News/2009/TaylorPCCPPrizes.asp(Accessed on 5th August 2009)
Stan Golunski has recently been appointedDeputy Director of the Cardiff CatalysisInstitute; he was formerly TechnologyManager of Gas Phase Catalysis at theJohnson Matthey Technology Centre atSonning Common in the U.K. His researchinterests include catalytic aftertreatmentand reforming.
References
Andy York is a Johnson Matthey ResearchFellow in the Department of ChemicalEngineering and Biotechnology at theUniversity of Cambridge, U.K. Hisresearch interests lie at the interfacebetween catalyst chemistry and reactionengineering.
The Reviewers
CATALYSIS – APPLIED AND PHYSICAL ASPECTSCatalytically Active, Magnetically Separable, andWater-Soluble FePt Nanoparticles Modified withCyclodextrin for Aqueous Hydrogenation ReactionsK. MORI, N. YOSHIOKA, Y. KONDO, T. TAKEUCHI and H.YAMASHITA, Green Chem., 2009, 11, (9), 1337–1342
Thermal decomposition of Fe(CO)5, followed byreduction of Pt(acac)2 in the presence of oleic acidand oleylamine, gave FePt nanoparticles (1) with Fe-rich cores and Pt-rich shells. (1) were subsequentlytreated with γ-cyclodextrin (γ-CD). FePt-γ-CD (2)exhibited superparamagnetic behaviour at 300 K. (2)was used for aqueous hydrogenation reactions, witheasy recovery of (2) by applying an external magnet.
Catalytic Inactivation of Bacteria Using Pd-Modified TitaniaL. R. QUISENBERRY, L. H. LOETSCHER and J. E. BOYD, Catal.Commun., 2009, 10, (10), 1417–1422
For the photocatalytic sterilisation of Escherichia coliin H2O, Pd/TiO2 was faster than Pt/TiO2. Pd/TiO2
was also active in the absence of light. Pd/TiO2 tem-porarily lost bactericidal activity after use, but wasreactivated in air. It is proposed that the Pd metal onthe surface of Pd/TiO2 is reduced in solution duringthe reaction, and must be reoxidised to regain activity.The reduction may initiate the bactericidal activity.
CATALYSIS – REACTIONSIridium Catalysed Alkylation of 4-HydroxyCoumarin, 4-Hydroxy-2-quinolones and Quinolin-4(1H)-one with Alcohols under Solvent FreeThermal ConditionsR. GRIGG, S. WHITNEY, V. SRIDHARAN, A. KEEP and A.DERRICK, Tetrahedron, 2009, 65, (36), 7468–7473
Ir-catalysed alkylation of the title compounds withsubstituted benzyl and aliphatic alcohols under solvent-free heating gave the monoalkylated products in highto excellent yield. 3,3'-Bis (heterocyclyl) methane prod-ucts can arise via a Michael addition pathway. Thealkylation of 4-hydroxy-1-methyl-2(1H)-quinoline withBzOH, KOH and the Ir chloro-bridged [Cp*IrCl2]2
dimer was carried out at 110ºC for 48 h in a sealed tube.
An Alternative Synthesis of Tamiflu®: A SyntheticChallenge and the Identification of a Ruthenium-Catalyzed Dihydroxylation RouteK. YAMATSUGU, M. KANAI and M. SHIBASAKI, Tetrahedron,2009, 65, (31), 6017–6024
A Ru-catalyzed dihydroxylation synthetic route wasidentified for Tamiflu®, which removes the need fora Mitsunobu inversion step. Only 0.5 mol% of RuCl3was required. The use of explosive trifluoroperaceticacid, generated in situ, is also avoided.
EMISSIONS CONTROLRe-evaluation and Modeling of a CommercialDiesel Oxidation CatalystY.-D. KIM and W.-S. KIM, Ind. Eng. Chem. Res., 2009, 48, (14),6579–6590
A modelling approach to predict the performance ofa DOC used published experimental data and a newset of conversion experiments. Steady-state experi-ments with DOCs (Pt supported on an Al2O3
washcoat) mounted on a light-duty turbochargeddiesel engine were carried out. The reaction rates forCO, HC, and NO oxidations in diesel exhaust overfresh Pt/Al2O3 were determined in conjunction with atransient 1D heterogeneous plug-flow reactor model.
NOx Abatement for Lean-Burn Engines underLean–Rich Atmosphere over Mixed NSR-SCRCatalysts: Influences of the Addition of a SCRCatalyst and of the Operational ConditionsE. C. CORBOS, M. HANEDA, X. COURTOIS, P. MARECOT, D.DUPREZ and H. HAMADA, Appl. Catal. A: Gen., 2009, 365,(2), 187–193
The NOx removal efficiency of a Pt-Rh/Ba/Al2O3
NSR model catalyst under a lean/rich atmospherewas improved by the addition of a SCR catalyst(Co/Al2O3 or Cu/ZSM-5). Both SCR catalysts wereable to reduce NOx using the NH3 formed during therich cycles on Pt-Rh/Ba/Al2O3. With Cu/ZSM-5,this was independent of the reductant used (CO orH2) and of the reduction time (10, 5 or 2.5 s).
FUEL CELLSOrigin and Quantitative Analysis of the ConstantPhase Element of a Platinum SOFC Cathode Usingthe State-Space ModelS. RICCIARDI, J. C. RUIZ-MORALES and P. NUÑEZ, Solid StateIonics, 2009, 180, (17–19), 1083–1090
A SOFC cathode was investigated using SEM, elec-trochemical impedance spectroscopy and simulationsusing the state-space model. The kinetic parameterswere determined. The triple phase boundary length wasmeasured and its width deduced. A quantitative analysisof the constant phase element using surface roughnessand energy activation distribution is presented.
Fabrication of High Precision PEMFC MembraneElectrode Assemblies by Sieve Printing MethodA. B. ANDRADE, M. L. MORA BEJARANO, E. F. CUNHA, E.ROBALINHO and M. LINARDI, J. Fuel Cell Sci. Technol., 2009,6, (2), 021305 (3 pages)
A sieve printing technique was used for the prepa-ration of PEMFC gas diffusion electrodes. MEAevaluation was carried out in a 25 cm2 single PEMFCwith loadings of 0.4 mg Pt cm–2 and 0.6 mg Pt cm–2
on the anode and cathode, respectively. The MEAshad higher power density than spray printed ones.
Platinum Metals Rev., 2009, 53, (4), 226–227 226
ABSTRACTS
DOI: 10.1595/147106709X475324
Platinum Metals Rev., 2009, 53, (4) 227
Synthesis of Intermetallic PtZn Nanoparticles byReaction of Pt Nanoparticles with Zn Vapor andTheir Application as Fuel Cell CatalystsA. MIURA, H. WANG, B. M. LEONARD, H. D. ABRUÑA and F. J.DiSALVO, Chem. Mater., 2009, 21, (13), 2661–2667
Intermetallic PtZn nanoparticles (1) were synthe-sised by reaction of C-supported Pt nanoparticleswith Zn vapour at 500ºC for 8 h under flowing N2 atatmospheric pressure. The catalytic activities of sup-ported (1) toward formic acid and MeOHelectrooxidation were studied by differential electro-chemical mass spectrometry. (1) exhibited highercurrents for both oxidations than supported Ptnanoparticles with similar particle sizes.
METALLURGY AND MATERIALSFacile Approach to the Synthesis of 3D PlatinumNanoflowers and Their ElectrochemicalCharacteristicsJ. N. TIWARI, F.-M. PAN and K.-L. LIN, New J. Chem., 2009, 33,(7), 1482–1485
3D Pt nanoflowers (1) were synthesised by a poten-tiostatic pulse plating method on a Si substrate.Electrochemical analysis established that (1) had amuch larger active surface area than a Pt thin film bya factor of > 110, and were likely preferentially ori-ented in the (100) and (110) surface planes. (1)exhibited excellent electrocatalytic activity towardMeOH oxidation and a high CO tolerance as com-pared with a Pt thin film.
Fe Oxidation versus Pt Segregation in FePtNanoparticles and Thin FilmsL. HAN, U. WIEDWALD, B. KUERBANJIANG and P. ZIEMANN,Nanotechnology, 2009, 20, (28), 285706 (7 pages)
The oxidation behaviour of differently sized FePtnanoparticles (1) was investigated by XPS and com-pared to a FePt reference film. For the as-preparedsamples Fe3+ is formed, becoming detectable forexposures to pure O2 above 106 langmuir, while Pt0
remains. After annealing at 650ºC, large (1) as well asthe reference film exhibited a 100–1000 timesenhanced resistance against oxidation, whereas small(1) (diameter 5 nm) showed no such enhancement.
Atomic-Level Pd–Au Alloying and ControllableHydrogen-Absorption Properties in Size-Controlled Nanoparticles Synthesized byHydrogen ReductionH. KOBAYASHI, M. YAMAUCHI, R. IKEDA and H. KITAGAWA,Chem. Commun., 2009, (32), 4806–4808
PVP-protected Pd nanoparticles were prepared fromthe alcoholic reduction of PdCl2 in the presence ofPVP. An aqueous solution of HAuCl4 was added andthe mixture was stirred under H2 gas to form Pd-Aualloy nanoparticles. 20 at.% of Au in Pd suppressed H2
absorption completely. The amount of H2 absorptionis controllable by low-concentration alloying with Au.
APPARATUS AND TECHNIQUENanocomposite Based on Depositing PlatinumNanostructure onto Carbon Nanotubes through aOne-Pot, Facile Synthesis Method forAmperometric SensingD. WEN, X. ZOU, Y. LIU, L. SHANG and S. DONG, Talanta, 2009,79, (5), 1233–1237
Pt nanoparticles deposited onto carbon MWNTs,through direct chemical reduction, can electrocatalysethe oxidation of H2O2 and substantially raise theresponse current. Glucose oxidase (GOD) was immo-bilised on the nanocomposite-based electrode with athin layer of Nafion. This glucose biosensor with aGOD loading concentration of 10 mg ml–1 had adetection limit of 3 μM and a response time of 3 s.
BIOMEDICAL AND DENTALInhibition of Transcription by Platinum AntitumorCompoundsR. C. TODD and S. J. LIPPARD, Metallomics, 2009, 1, (4), 280–291
Structural investigations of Pt–DNA adducts andthe effects of these lesions on global DNA geometryare reviewed. Research detailing inhibition of cellulartranscription by Pt–DNA adducts is presented. Amechanistic analysis of how DNA structural distor-tions induced by Pt damage may inhibit RNAsynthesis in vivo was carried out. (155 Refs.)
CHEMISTRYSynthesis and Structural Characterization ofBinuclear Palladium(II) Complexes ofSalicylaldimine DithiosemicarbazonesT. STRINGER, P. CHELLAN, B. THERRIEN, N. SHUNMOOGAM-GOUNDEN, D. T. HENDRICKS and G. S. SMITH, Polyhedron, 2009,28, (14), 2839–2846
The title complexes were synthesised by the reactionof ethylene- and phenylene-bridged dithiosemicar-bazones with Pd(PPh3)2Cl2. Two representative Pdcomplexes were characterised by XRD. The two Pdcentres are coordinated in a slightly distorted square-planar geometry, which gives rise in each case to five-and six-membered chelate rings. The ligands coordi-nate to Pd in a tridentate manner, through thephenolic O, imine N and thiolate S atoms.
Synthesis, Properties and Crystal Structures ofVolatile ββ-Ketoiminate Pd Complexes, Precursorsfor Palladium Chemical Vapor DepositionG. I. ZHARKOVA, P. A. STABNIKOV, I. A. BAIDINA, A. I.SMOLENTSEV and S. V. TKACHEV, Polyhedron, 2009, 28, (12),2307–2312
β-Aminovinylketone ligands CH3C(NH2)CHC(O)CH3
and CH3C(NHCH3)CHC(O)CH3 were synthesised.Their reaction with PdCl2 in an amine mediumafforded the complexes Pd[CH3C(NH)CHC(O)CH3]2
(1) and Pd[CH3C(NCH3)CHC(O)CH3]2 (2). In (1) and(2), the Pd atom exhibits square coordination, Pd O2N2.
CATALYSIS – APPLIED ANDPHYSICAL ASPECTSPreparation of Platinum on Activated CarbonUNIV. KEBANGSAAN MALAYSIA World Appl. 2009/057,992
A catalyst with ≥ 40 wt.% loading of Pt and meanparticle size of 28 μm is prepared by adding a solutionof H2PtCl6 or (NH4)2PtCl4 in aqua regia to activated C powder with particles 20–30 μm in size, pretreatedwith HNO3. A base such as NH4OH is added to raisethe pH to 9.7–9.9. The solution is boiled and calcinedby heating at 120–130°C then at 340–360°C.
Palladium-Gallium Hydrogenation CatalystsMAX-PLANCK-GESELLSCHAFT World Appl. 2009/062,848
Optionally supported, ordered intermetallic PdGacompounds are prepared by reacting a Pd compound,preferably Pd(acac)2, with a Ga compound, preferablya Ga halide, in the presence of a reductant such asLiBEt3H and optionally a solvent such as THF ordiglyme. Alternatively, Pd is reacted with a vaporisedGa compound, such as GaI3. Particular applicationfor the selective conversion of ethyne to ethene in thepresence of an excess of ethene is claimed.
CATALYSIS – INDUSTRIAL PROCESSTwo-Stage Distillate to Gasoline ConversionCONOCOPHILLIPS CO U.S. Appl. 2009/0,134,061
Distillate with research octane number (RON)25–50, is converted to gasoline with RON > 65, bycontact with: (a) 0.5–5 (preferably 0.5–3) wt.% Ptand/or Pd on an acidic support, preferably zeolite, inthe presence of H2, at 220–260ºC, then (b) 0.5–5(preferably 0.5–3) wt.% Ir and optionally Ni on asupport such as SiO2 or Al2O3, at 280–330ºC.
CATALYSIS – REACTIONSIridium Catalyst for Nitrile HydrationUNIV. OKAYAMA Japanese Appl. 2009-023,925
Amides are produced from nitriles under mild con-ditions using a catalyst system formed from an Ircomplex, XIrL2, YIrZ2 or (YIrZ)2, with an electron-withdrawing organic phosphine; where X = a Group15 element or a bidentate ligand containing O–; L = aphosphine or a neutral ligand exchangeable with aphosphine; Y = a multidentate ligand containing C– orN–; and Z = a negatively charged monodentate ligand.
EMISSIONS CONTROLEfficient Treatment of Particulate MatterETM INT. LTD World Appl. 2009/090,447
A catalyst cartridge contains mineral fibres with den-sity 300–1000 g m–3, composed of ≥ 80 wt.% SiO2 withPt and/or Ir, arranged in radial undulations with recti-linear sections of length l perpendicular to the directionof gas flow. The fibres are 0.3–1 mm thick, with dis-tance d between undulations such that l/d = 5–12.
Lean NOx Trap and Reduction CatalystTOYOTA MOTOR CORP Japanese Appl. 2009-028,575
A NOx occlusion and reduction catalyst has Rh sup-ported on two different oxide materials, such as amixture of Al2O3 and ZrO2-TiO2, in the ratio 1:9–5:1.Rh solubility is ≥ 70% in the first and < 70% in thesecond oxide, when heat treated at > 750ºC and at aloading of 0.01–5 wt.% Rh. During lean operation, Rhgoes into solid solution in the first oxide, preventinggrain growth and sintering. In the rich phase, Rh pre-cipitates out of solution to catalyse NOx reduction.
FUEL CELLSMembrane Electrode Assembly EvaluationGM GLOBAL TECHNOL. OPER. INC
U.S. Appl. 2009/0,124,020A PEMFC MEA is soaked in an unsaturated organ-
ic compound, such as 0.5–2.0 wt.% polyoxyethylene(10) oleyl ether (Brij® 97) in H2O, and then stainedwith a strongly oxidising agent, specifically OsO4. TheMEA is embedded in an epoxy and thin sections forviewing using TEM are prepared. Ionomer and cata-lyst particles will appear as dark regions and pores aslight regions, allowing porosity and size and distribu-tion of particles to be determined.
Membrane Electrode Assembly with Anion ExchangeTOSHIBA CORP Japanese Appl. 2009-026,690
A membrane/electrode composite includes ananion exchange substance, deposited on the anodecatalyst layer or the electrolyte membrane, which cap-tures mobile Ru-containing anions to prevent catalystdegradation. The substance is deposited as a film, oras particles with diameter 0.01–50 μm, in mass ratioof 5:95–90:10 relative to the anode catalyst, or at aloading of 1–50 mg cm–2 of electrode surface area.
METALLURGY AND MATERIALSPlatinum Jewellery AlloyHEIMERLE & MEULE GmbH World Appl. 2009/059,736
A Pt alloy consists of (in wt.%): 94.0–96.5 Pt(preferably 95.1–95.5); 2.5–4.5 W (preferably3.7–3.8); 0.5–3.0 Cu (preferably 0.9–1.1); and0.02–2.0 (preferably 0.04–0.07) of at least one of Ru,Rh and Ir, and is free of Au. It offers high hardnessand resistance to abrasion combined with good workability and cold formability. Semi-finished jewellery components are also claimed.
Corrosion-Resistant Platinum-Rhodium AlloyISHIFUKU MET. IND. CO, LTD Japanese Appl. 2009-035,750
A PtRh alloy for high-temperature and electricalapplications is described as possessing good resistanceto corrosion caused by P, Pb, As, B, Bi, Si, Zn, but inparticular P. It consists of 10–40 wt.% Rh with at leastone of (in wt.%): 0.1–5.0 V, Cr, Nb, Mo, Ta, Reand/or W; 0.1–3.0 Mn and/or Co; 0.3–5.0 Ru, Pd, Ir,Au and/or Ag; and/or 0.01–1.0 Al, and the balance Pt.
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NEW PATENTS
Platinum Metals Rev., 2009, 53, (4)
APPARATUS AND TECHNIQUESpark Plug with Iridium Alloy TipHONEYWELL INT. INC U.S. Appl. 2009/0,127,996
A spark plug with electrode tip formed from an Iralloy is presented. The alloy composition is (in wt.%):60–70 Ir, 30–35 Rh, 0–10 Ni and has minor additions(in ppm) either: (a) 3500-4500 Ta and 100-200 Zr, or (b) 50–100 Ce. These allow for better bonding of thetip with the Ni alloy of the electrode body throughinterdiffusion. The Ir alloy offers high wear resistance.
Unsupported Palladium MembranesJ. D. WAY et al. U.S. Appl. 2009/0,176,012
Defect-free, 7.2 μm-thin Pd membranes are formedby electroless plating on a support such as mirror-finished stainless steel, in an EDTA-free plating bathat 50ºC with addition of 1 part per 100 of hydrazinesolution (3 M). The support may be seeded withmetallic Pd crystallites from Pd acetate. A secondmetal such as Cu, Ag or Au may also be deposited byelectroless plating and the membrane homogenisedby annealing. The membrane is freed from the support by scoring the edges. H2 permeabilities maybe equivalent to thicker membranes and H2/N2 selec-tivity can reach 40,000.
Porous Platinum NanoparticlesUNIV. MIYAZAKI Japanese Appl. 2009-062,571
Monocrystalline Pt nanoparticles with nanopores, foruse in catalysts, electrodes or sensors, and their methodof production are described. The particles are sheets2–25 nm thick with outer diameter 30–600 nm. Thepores may have diameter 1–3.5 nm or may be ellipticalor rectangular with dimensions 1 × 3.5 to 3.5 × 10 nm,and are arrayed at regular intervals of 4–5 nm or atintervals varying from 1–5 nm. The particles may becomposed of Pt, Pt and a base metal, or an alloy of Ptwith Pd, Rh, Ir, Ru, Au, and/or Ag.
BIOMEDICAL AND DENTALAnticancer Rh(III) and Ir(III) ComplexesFREIE UNIV. BERLIN European Appl. 2,072,521
Novel octahedral metal(III) polypyridyl complexesM(hal)3(sol)(pp) for the prevention and treatment ofcancer and its metastases are claimed, described asexhibiting superior cytotoxic activity in cell cultures.M is Rh or Ir, preferably Rh. Sol is a solvent, prefer-ably DMSO or H2O; hal is a halogen, preferably Cl orBr, or a psuedohalogenide, preferably SCN; and pp isa polypyridyl ligand, preferably dpq, dppz or dppn.
Ultra-Low Magnetic Susceptibility Palladium AlloysDERINGER-NEY INC U.S. Appl. 2009/0,191,087
Pd alloys for biomedical components compatiblewith the use of magnetic resonance imaging areclaimed. The composition is (at.%): ≥ 75 Pd; 3–20 Sn,Al or Ta; plus one or more of whichever of Sn, Al orTa are not used in the binary composition, and/orNb, W, Mo, Zr or Ti, up to a total of 22 at.%. Thealloys are formulated such that the volume magneticsusceptibility (cgs) is between 3 × 10–6 and –3 × 10–6.
ELECTRICAL AND ELECTRONICSRuthenium-Doped Semi-Insulator for Laser DiodeT. KITATANI et al. U.S. Appl. 2009/0,129,421
A semi-insulating layer is formed by doping a semi-conductor material such as InP with Ru, Os, Rh or Ti,but in particular Ru. It is included between the p-typeand n-type semiconductor layers to limit current leak-age in the window region of a semiconductor laser,particularly a short cavity edge-emitting laser.
Palladium Complex for Printed CircuitsHEWLETT-PACKARD DEV. CO, LP
U.S. Appl. 2009/0,201,333A Pd aliphatic amine complex (1) in a liquid carrier
is inkjet printed on a substrate, a second compositioncontaining a reducing agent such as formic acid isapplied and the substrate is heated at 50–80ºC toreduce (1) to Pd metal. Alternatively, (1) can beapplied as a seed layer for a subsequent conductivemetal such as Pt, Pd, Rh, Au, Cu, Ni or various alloys.
PHOTOCONVERSIONLuminescent Platinum ComplexesARIZONA STATE UNIV. World Appl. 2009/086,209
Pt(II) di(2-pyrazolyl)benzene chloride and itsanalogs, which are obtained by forming an aromaticsix-membered ring, 1,3-di-substituted by aromaticfive-membered heterocyles such as pyrazolyl, imida-zolyl, thiazolyl or substituted groups thereof, andreacting with an acidic Pt-containing solution. Thebenzene may be fluorinated, difluorinated, methylated,or replaced by pyridine. Cl may be replaced by a phe-noxy group. The Pt(II) complexes, which in someembodiments are phosphorescent, are claimed for useas blue or white light emitters in OLEDs.
REFINING AND RECOVERYRuthenium Recovery from Solid ComponentsTOSHIBA KK World Appl. 2009/093,730
Ru is selectively recovered from hard disks, elec-trodes etc. by contact with an aqueous solution to forma Ru compound which is subsequently eluted and sep-arated by filtration. The aqueous solution can be: (a)formic acid, (b) oxalic acid, (c) an acid and sugars, or(d) an acid and formic acid, alcohols, aldehydes or anacetal/hemiacetal compound (or precursors thereof).For (c) and (d), the acid is preferably 1–90 wt.% of thesolution. The solid may also be oxidised by one of O2,air, O3 or H2O2 for second-pass removal of Ru.
Dry Method for Recovering PGMsDOWA METALS AND MINING CO LTD
Japanese Appl. 2009-024,263A sealed electric furnace is charged with spent pgm-
containing solid components and granular Cu oxidehaving a particle diameter of 0.1–10 mm, a powderedreducing agent and a flux, and melting is done at pres-sures < 1 atm. The pgms preferentially dissolve in themolten Cu, and the oxides are removed in the slag,which has final Cu content of < 3%.
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NAME INDEX TO VOLUME 53Page Page Page Page
Abdelkader, A. 224
Abe, T. 52, 106
Abruna, H. D. 227
Abu Sheikha, G. 176
Actis Grande, M. 200
Adams, R. D. 50
Adler, J. 175
Adschiri, T. 154
Advani, S. G. 175
Ager, D. J. 203, 204
Agert, C. 154
Aggarwal, V. K. 88
Akçin, N. 105
Albrecht, B. 40
Al-Noaimi, M. 176
Alonso, E. 43
Alvarez, P. J. J. 105
Amore, S. 51
An, G. 105
Ananikov, V. P. 105
Anderson, C. 41
Anderson, J. A. 112, 222
Andrade, A. B. 226
Andrews, P. 36
Antipin, M. Yu. 105
Antolini, E. 51
Antonova, O. V. 138
Anzai, Y. 51
Arbizo, C. 43
Arico, A. S. 151
Aronson, J. 36
Arunachalampillai,
A. 52
Auberson, A. 25
Baca, E. 40
Bäckvall, J.-E. 203
Baddeley, C. 222
Bagshawe, K. 36
Baidina, I. A. 227
Balle, P. 175
Balzani, V. 45, 46
Barigelletti, F. 45
Barnard, C. 36, 67
Basi, M. 41
Battaini, P. 21, 198, 199
Beebe, Jr., T. P. 175
Beletskaya, I. P. 105
Bertel, E. 176
Bhat, V. V. 176
Bhushan, B. 52
Blankenstein, U. 41
Blaser, H.-U. 207
Blatter, A. 189
Blom, D. A. 50
Bloxham, L. 179
Blumberg, P. 43
Boggs, M. E. 175
Bonder, M. J. 51
Book, D. 84
Booyens, S. 224
Borisov, S. M. 106
Boro, B. J. 52
Borzone, G. 51
Bousa, M. 41
Bouzek, K. 148
Boyd, J. E. 226
Braibant, C. 40
Breit, B. 207
Brelle, J. 189
Brock, P. 36
Bull, S. 89
Bullock, J. 40
Bullock, J. P. 106
Bultel, Y. 154
Burch, R. 223
Byriel, I. P. 148
Calman, K. 36
Calvert, H. 36
Cameron, D. S. 147
Campagna, S. 45
Campbell, C. 221
Capela, S. 170
Captain, B. 50
Carlson, B. 106
Casey, P. 42
Catlow, R. 221
Chakraborty, D. 149
Chang, L. 105
Chaplin, D. 206
Chayama, K. 102
Chellan, P. 227
Chen, C.-Y. 52
Chen, J.-G. 52
Chen, W. 86
Cho, B.-G. 106
Choi, J.-S. 169
Chong, L. C. 50
Chown, L. H. 2, 155
Christgen, B. 152
Christie, D. A. 35
Claassen, P. 82
Clarke, N. 41
Colacot, T. J. 183
Compagnoni, G. 188
Contescu, C. I. 176
Cooke, S. 43
Corbos, E. C. 226
Cordin, M. 176
Cornish, L. A. 2, 69, 155
Correia, I. 176
Cortes Felix, N. 164
Corti, C. W.
21, 24, 198, 200
Coughlin, M. 42
Counsell, J. 223
Courtois, X. 226
Creeth, A. M. 151
Cunha, E. F. 226
Curry, R. J. 50
Danks, M. 198
Davies, P. 86, 87
Davis, S. 25
Dawson, G. 200
De Castro, E. 40
de Vries, A. 204
Deisl, C. 176
Delsante, S. 51
Demkowicz, P. 105
Derrick, A. 226
Deutschmann, O. 175
Dinderman, M. A. 106
Ding, K. 105
Dingwall, L. 224
DiSalvo, F. J. 227
Diskin-Posner, Y. 52
Divakar, D. 50
Do, J. S. 175
Doná, E. 176
Dong, S. 227
Douglas, A. 2, 69
Douglas, P. 51
Dressick, W. J. 106
Dudek, D. 51
Duesler, E. N. 52
Dufour, J. 176
Duisberg, M. 175
Dujardin, C. 168
Dupont, J. 67
Duprez, D. 226
Dyson, P. J. 35
Eccarius, S. 154
Edwards, D. 223
Edwards, H. 89
Edwards, J. 223
Egebo, T. 147
Eichinger, B. E. 106
El-Eswed, B. 176
Enders, M. 50
Epling, W. 168
Fang, Y.-L. 105
Feller, M. 52
Ferguson, S. 40
Fermvik, A. 101
Ficicilar, B. 153
Fischer-Bühner, J.
22, 201
Fisher, J. M. 153
Foo, R. 164
Fordred, P. 89
Forzatti, P. 50
Fossey, J. S. 86, 89
Franchini, C. 176
Frost, C. 86, 89
Frost, J. 85, 223
Fryé, T. 22, 23
Furimsky, E. 135
Furukawa, Y. 88
Gallego, N. C. 176
Gamino-Arroyo, Z. 100
Gammon, R. 82
Gan, J. 105
Gayduk, K. A. 105
Gellman, A. 222
George, E. 145
Georges, S. 154
Gilby, S. 152
Giunti, T. 82
Gladden, L. 222
Glaner, L. 2, 155
Gökaliler, F. 150
Goldberg, K. I. 52
Golunski, S. E. 221, 223
Gonzalez, E. R. 51
Gopinath, C. S. 224
Grahame-Smith, D.
36
Gralla, R. 36
Grant, R. A. 100
Gray, P. 150
Green, R. 79
Gregory, D. 83
Greinke, R. 202
Platinum Metals Rev., 2009, 53, (4) 231
Griffith, W. P. 209
Grigg, R. 226
Grimwade, M. 202
Grundmann, A. 154
Gülzow, E. 151
Guo, M. 50
Haas, W. 106
Hadjipanayis, G. C. 51
Hagelueken, C. 41
Hallikainen, A. 105
Hamada, H. 226
Hammond, C. 224
Han, B. 105
Han, L. 227
Hancock, F. 188, 204
Haneda, M. 226
Harrap, K. 36
Harris, R. 84
Harrison, J. 79
Haruta, M. 222
Heck, K. N. 105
Helliwell, J. 81
Hendricks, D. T. 227
Hepworth, R. 79
Hernández, J. R. 166
Hill, P. J. 69
Hiro, T. 165
Hiromi, C. 52
Ho, K.-C. 52
Hoeschele, J. 36
Hoge, G. 207
Holdcroft, S. 52
Howard, K. 223
Huang, C.-J. 105
Huang, Y. H. 51
Huot, J. 176
Hutchings, G. 222
Huuhtanen, M. 105
Ianniello, R. 42
Ikariya, T. 203, 208
Ikeda, N. 106
Ikeda, R. 227
Inoue, M. 52
Irandoust, M. 106
Iron, M. A. 52
Itakura, T. 106
Iwata, Y. 165
Iyngaran, P. 224
Izatt, S. 41, 43
Jackson, D. 223
Jacobsen, R. 41, 43
James, K. 43
Jenkins, S. 221
Jin, Y. 176
Jiskra, J. 42
Johnson, M. T. 52
Johnson, T. V. 37
Jollie, D. 182
Jones, H. 202
Jones, M. 202
Joshaghani, M. 106
Judson, I. 36
Jun, B.-H. 50
Kallinen, K. 105
Kallio, T. 58
Kaminsky, W. 106
Kanai, M. 226
Kanehara, M. 106
Kang, H. 50
Keep, A. 226
Keiski, R. L. 105
Kemp, R. A. 52
Kendall, K. 78, 80
Khrustalev, V. N. 105
Khurshid, H. 51
Kiely, C. 222
Kim, I.-K. 106
Kim, J.-H. 50
Kim, P. S. 165
Kim, W.-S. 226
Kim, Y.-D. 226
Kitagawa, H. 227
Kitami, T. 52
Kittelson, D. B. 31
Kjellin, P. 51
Klein, J.-M. 154
Klerke, A. 149
Klimant, I. 106
Klotz, U. 201
Kobayashi, H. 227
Koch, F. 79
Kohl, G. 50
Kolb, G. 172
Kolli, T. 105
Kondo, Y. 226
Kontturi, K. 58
Kossov, A. 98
Kramer, E. P. 101
Krog, O. 147
Kuai, P. 50
Kuerbanjiang, B. 227
Kumar, P. 128
Kureti, S. 175
Kuriyama, W. 205
Kurz, T. 154
Kwak, K. J. 52
Lapidus, G. T. 100
Latini, A. 176
Le Ret, C. 205
Lee, M. H. 175
Lee, S.-H. 50
Lee, W.-Y. 153
Lee, Y.-S. 50
Lei, Y. J. 43
Leitus, G. 52
Lennon, I. 205
Leonard, B. M. 227
Lewis, J. 85
Li, G. 176
Li, J. 175
Li, J.-Y. 52
Liang, X. 50
Liang, Z. X. 105
Libuda, J. 170
Lietti, L. 50
Lin, K.-L. 227
Lin, Z. 176
Linardi, M. 226
Linderoth, S. 154
Lindner, E. 176
Lippard, S. J. 227
Liu, C.-J. 50
Liu, Y. 227
Liu, Z. 105
Loetscher, L. H. 226
Lohwongwatana, B. 25
Lopes, T. 51
Loschialpo, P. 106
Lu, W. 176
Luo, Y. 176
Lupton, D. 42, 145
Ma, D. 176
Maerz, J. 24, 200
Maggian, D. 202
Mahittikul, A. 105
Manikandan, D. 50
Mansur, M. B. 100
Manziek, L. 40
Marecot, P. 226
Martin, A. 79
Matsubara, H. 169
Matsuzono, Y. 175
Mauser, A. 78
McCarney, J. 172
McCloskey, J. 25
McFarlane, A. 224
Mekasuwandumrong,
O. 175
Melke, J. 153
Miao, S. 105
Miller, J. T. 105
Millet, C.-N. 170
Milstein, D. 52
Miner, W. 36
Mishra, R. 202
Miura, A. 227
Modolo, G. 101
Montero, J. 224
Mora Bejarano, M. L.
226
Morgan, K. 223
Mori, K. 226
Muhamad, E. N. 51
Murakumo, T. 69
Murata, K. 205
Murrer, B. 36
Nagarajan, S. 223
Nakatsuji, T. 166, 175
Nakken, T. 83
Narita, H. 101
Naylor, R. 36
Nishimura, T. 89
Nova, I. 50
Nunez, P. 226
Nuss, G. 106
Nutt, M. O. 105
Ó Dubhghaill, C. 202
Obuchi, A. 167
Offer, G. J. 219
Ohara, S. 153, 154
Ouyang, F. 50
Palacio, M. 52
Palmer, S. 78
Palmqvist, A. E. C. 51
Pan, F.-M. 105, 227
Pan, Z. F. 43
Pandey, D. K. 91
Panfilov, P. 138
Panpranot, J. 175
Park, H.-S. 106
Park, J. 50
Park, J.-G. 106
Park, J.-Y. 106
Parkinson, P. 41
Parodi, N. 51
Penfold, G. 25
Pentz, L. 98
Pereira Morais, M. P.
89
Petti, D. 105
Pfaltz, A. 205
Pfeffer, M. 67
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Phelan, G. D. 106
Phillips, P. R. 27
Pickup, P. G. 175
Pilyugin, V. P. 138
Ploof, C. 201
Pollet, B. G. 78
Poulston, S. 112
Pourshahbaz, M. 106
Prasad, A. K. 175
Prasassarakich, P. 105
Praserthdam, P. 175
Pratsinis, S. E. 11
Price, G. 86
Pridmore, S. 89
Prior, J. 41
Pritzkow, H. 50
Puhakka, E. 153
Quisenberry, L. R. 226
Rafiee, E. 106
Raja, R. 50
Rangel, C. M. 150
Rau, J. V. 176
Raykhtsaum, G. 202
Rayment, T. 222
Redinger, J. 176
Rempel, G. L. 105
Reynolds, B. 36
Ricciardi, S. 226
Ricketts, S. R. 51
Riess, M. 40
Robalinho, E. 226
Roberts, W. 225
Robinson, D. J. 100
Rossmeisl, J. 152
Rowsell, L. 112
Rudd, J. 36
Ruiz-Morales, J. C. 226
Ryan, M. 216
Saf, R. 106
Sage, P. 25
Samulski, E. T. 51
Sánchez-Loredo, M. G.
102
Sanderson, R. 43
Sanger, G. 36
Santasalo, A. 58
Saruyama, M. 106
Sato, K. 154
Sato, N. 175
Satsuma, A. 164, 165
Sawabe, K. 165
Scandola, F. 45
Schädel, B. T. 175
Schmehl, R. 46
Schmuck, M. 106
Schott, F. J. P. 175
Schulz, G. L. 52
Schuster, H. 25, 201
Shang, L. 227
Shaw, M. 88, 89
Sheu, J.-T. 105
Shibasaki, M. 86, 226
Shimizu, K. 165
Shimon, L. J. W. 52
Shinozaki, K. 106
Shulgin, D. 42
Shunmoogam-Gounden,
N. 227
Si, Y. 51
Silva, F. 202
Silva, S. R. P. 50
Singh, D. 91
Singhal, S. C. 147
Sivakumar, T. 50
Sjunnesson, L. 148
Skea, J. 78
Smith, A. W. J. 112
Smith, D. 106
Smith, G. S. 227
Smith, R. A. P. 55, 109
Smolentsev, A. I. 227
Sodeoka, M. 208
Somboonthanakij, S.
175
Somorjai, G. 221
Sorel, C. 101
Sridharan, V. 226
Stabnikov, P. A. 227
Stadelmann, P. A. 70
Stolojan, V. 50
Stone, F. 221
Strauss, J. 25, 201
Stringer, T. 227
Strobel, R. 11
Sullivan, S. P. 175
Sun, S.-G. 106
Sun, Y. 207
Sunjuk, M. 176
Süss, R. 2, 69, 155
Suzuki, K. 203
Sweidan, K. 176
Taguchi, A. 52
Takahashi, N. 170
Takeguchi, T. 51
Takemoto, Y. 203
Takeshita, K. 102
Takeuchi, T. 226
Tanaka, K. 206
Tandon, P. 123
Tang, J. 52
Tanizawa, M. 52
Tansey, E. M. 35
Tansey, T. 36
Tao, R. 105
Tasker, P. A. 102
Tattersall, D. 36
Taylor, H. S. 221
Teague, T. 201
Teranishi, T. 106
Terry, L. A. 112
Therrien, B. 227
Thomas, J. M. 50
Thomson, A. 36
Thumberg, M. A. 101
Tian, N. 106
Tian, X. 154
Tierney, B. 40
Tiwari, J. N. 227
Tkachev, S. V. 227
Todd, R. C. 227
Toops, T. J. 170
Trufan, E. 50
Tully, J. 43
Twigg, M. V. 27, 135
Tyler, C. 41
Tzeng, T.-C. 105
Ueda, W. 51
Umetsu, M. 154
Uozumi, Y. 175
Uttam, K. N. 123
Vargas, C. 101
Verdooren, A. 202
Wagner, G. 50
Walker, J. 98
Walport, M. 36
Wang, G. 51
Wang, H. 227
Wang, L. 176
Wang, Q. 176
Ward, M. D. 45
Welton, T. 176
Wen, D. 227
Wendt, O. F 52
Wenn, J. 36
Whitby, M. 214
Whitney, S. 226
Wiedwald, U. 227
Wiesner, K. 25, 201
Wilkinson, L. 36
Williams, G. 46
Williams, J. M. J. 86
Williams, R. 36
Williamson, I. 81
Willis, M. 86
Wills, M. 83, 84
Wilson, K. 225
Wiltshaw, E. 36
Wisniewski, M. 102
Wong, M. S. 105
Wong, W.-Y. 176
Woods, T. 36
Woollam, S. F. 100
Wright, J. C. 200, 202
Wright, K. 105
Wu, C.-G. 52
Wu, S.-J. 52
Xie, Y. 105
Xu, J. B. 105
Yadawa, P. K. 91
Yamada, Y. M. A. 175
Yamaguchi, T. 175
Yamamoto, H. 204
Yamashita, H. 226
Yamatsugu, K. 226
Yamauchi, M. 227
Yermakov, A. 138
Yezerets, A. 169
Yonkeu, A. 176
York, A. P. E. 221
Yoshioka, N. 226
Yu, X. 175
Zabetakis, D. 106
Zhang, F.-Y. 175
Zhang, J. 219
Zhao, T. S. 105
Zharkova, G. I. 227
Zhou, G.-J. 176
Zhou, Z.-Y. 106
Zhu, L. D. 105
Zhu, R. 50
Ziegenhagen, R. 189
Zielonka, A. 25
Ziemann, P. 227
Zito, D. 25
Zou, X. 227
Zucca, R. 176
Zuo, Y. 52
Züttel, A. 84
Page Page Page Page
Platinum Metals Rev., 2009, 53, (4), 233–240 233
SUBJECT INDEX TO VOLUME 53Page Page
a = abstract
(Z)-Acetamidocinnamic Acid Methyl Ester, reduction 203
Acetoxylation 221
Adsorption, ethylene, Pd-promoted zeolite 112
AFM Probes, Pt-coated Si, thermally-treated, a 52
Alcohols, aerobic oxidation, in H2O, a 175
aliphatic, in alkylation, a 226
benzyl, substituted, in alkylation, a 226
chiral, by reduction of esters 203
EtOH, oxidation 58, 105
electro-, a 106
fuels, for PEFC 58
generation of H2 78
MeOH, electrooxidation, a 227
oxidation, a 227
solvent, a 176
secondary, dynamic kinetic resolution 203
racemisation 203
Aldehydes, addition, across multiple C–C 86
fuels, for PEFC 58
Alkenes, formation 86
hydroacylation 86
hydrogenation, a 105
unfunctionalised, asymmetric reduction 203
Alkylation, 4-hydroxy coumarin, a 226
4-hydroxy-2-quinolones, a 226
quinolin-4(1H)-one, a 226
Alkylidene Carbenoids, by activation of alkynes 86
Alkynes, activation 86
hydroacylation 86
Amides, α-arylation 183
Amination, Buchwald-Hartwig, palladacycle catalysts 67
Amines, coupling reactions 183
Ammonia, storage 164
synthesis 135
Antimicrobial Agents 11
Apparatus and Technique, a 51, 227
Aryl Halides, coupling reactions 183
αα-Arylation, amides 183
esters 183
Autocatalysts, new production facility, for Russia 98
pgm demand, impact of CO2 legislation 179
recycling 40
Bacteria, catalytic inactivation, a 226
Biomedical and Dental, a 227
Book Reviews, “Carbons and Carbon Supported
Catalysts in Hydroprocessing” 135
“Fuel Processing: for Fuel Cells” 172
“Palladacycles: Synthesis, Characterization and
Applications” 67
“PEM Fuel Cell Electrocatalysts and Catalyst
Layers: Fundamentals and Applications” 219
“Photochemistry and Photophysics of
Coordination Compounds”, Parts I & II 45
“The Discovery, Use and Impact of Platinum Salts
as Chemotherapy Agents for Cancer” 35
Buchwald-Hartwig Amination, palladacycle catalysts 67
Butane, steam reforming, a 175
CAD/CAM, jewellery 21, 198
Cancer, anti-, drugs, cisplatin 35
palladacycles 67
Pt compounds, a 227
Capacitors, DRAM, Ru bottom electrodes, a 106
Carbon, pgm/activated charcoal, catalysts 135
pgm/C, catalysts 135
supported catalysts, hydroprocessing 135
Carbon Oxides, CO, clean-up, in fuel processing 172
contaminated gas, low pressure operation of PEFC 147
emissions, diesel 179
Carbon Oxides, CO, (cont.)+ H2, reduction of NOx, lean conditions, a 175
+ O2 221
oxidation, in diesel exhaust, a 226
selective catalytic reduction 164
selective oxidation 11
tolerant catalysts, for PEM fuel cells 219
CO
2
, emissions, legislation 179
Casting, industrial, Pt 209
investment, Pd alloys 21, 198
Pt alloys 21, 198
Catalysed Soot Filters 27, 179
Catalysis, Applied and Physical Aspects, a 50, 105, 226
asymmetric 203
book reviews 67, 135
concepts 221
conferences 86, 164, 203, 221
methodology 221
Reactions, a 50, 105, 175, 226
theories 221
Catalysts, book reviews 67, 135
C supported, hydroprocessing 135
four-way, see Four-Way Catalysts
heterogeneous, precious metals, for industry 40
surface characterisation, by XPS 55, 109
leaching, for new catalytic reactions, a 105
NOx control 27
petroleum, spent, sampling 40
pgm/activated charcoal, preparation 135
pgm/C, preparation 135
pgms, catalytic aftertreatment, vehicle emissions 221
precious metals, treatment, in plasma heater reactors 40
recycling, a 50, 226
refinery, precious metals, treatment, in PlasmaEnvi® 40
supported pgms, by flame synthesis 11
three-way, see Three-Way Catalysts
Catalysts, Iridium, Ir/γ-Al2O3, soot and NOx removal, a 50
Ir/ZSM-5, soot and NOx removal, a 50
IrBa/WO3-SiO2, CO-SCR 164
Catalysts, Iridium Complexes, [Cp*IrCl2]2, alkylation,
4-hydroxy coumarin, 4-hydroxy-2-quinolones,
quinolin-4(1H)-one, solvent-free heating, a 226
‘hydrogen borrowing’, for formation of C–C, C–N 86
[Ir(COD)(PCy3)(py)]PF6, hydrogenation of NRL, a 105
Ir Me-BoPhozTM, reduction of α,β-enoic acids 203
Ir phosphoramidites, synthesis of phenylalanines 203
Ir(III) quinolyl-functionalised Cp, hydrogenation, a 50
P,N-ligands, asymmetric reduction of alkenes 203
Catalysts, Osmium Complexes, OsO4 immobilised onto
polystyrene-sg-imidazolium resin,
dihydroxylation of olefins, a 50
Catalysts, Palladium, Au-Pd, direct synthesis of H2O2 221
preparation, pretreatment 221
Au-Pd/Al2O3, direct synthesis of H2O2 221
Au-Pd/C, direct synthesis of H2O2 221
Au-Pd/TiO2, direct synthesis of H2O2 221
Co/Pd-HFER, NO2-CH4 reaction 164
combustion, in fuel processing 172
diesel emission control systems 179
diesel oxidation catalysts 174
electrocatalysts, Pd-based, formic acid oxidation 58
Pd/C, anodes, for DFAFC, a 175
Pd/TiO2/C, anodes, for PEFC, a 51
Pd-Pt/hollow core mesoporous shell C, for PEMFC 147
Pt-Pd/C, for DEFCs, a 51
PdRu nanoparticles, anodes, for DMFC 147
nano-Pd/SiO2, 1-heptyne hydrogenation, a 175
by one-step flame spray pyrolysis, a 175
Pd(111), CO + O2 221
Pd, + Au, acetoxylation 221
+ Bi additive, hydrogenation 221
hydrodechlorination, a 105
Catalysts, Palladium, (cont.)Pd-on-Au, hydrodechlorination, a 105
Pd/activated charcoal, hydrogen activation 135
Pd-Al2O3, NO+H2+O2 164
Pd/Al2O3, Ar plasma reduced; glucose selective
oxidation, a 50
C5 olefin hydrogenation 221
effect of S, diesel oxidation, a 105
enantioselective hydrogenation 11
H2 thermally reduced; glucose selective oxidation, a 50
Pd/Ba/Al2O3, NOx storage 164
Pd/bentonite, hydrogenation of citral, a 50
preparation, effect of reduction, a 50
Pd/C, C–C bond forming processes 135
direct carbonylation reactions 135
dissociative H2 chemisorption 135
hydrogenation reactions 135
hydrogenolysis reactions 135
Pd/C black, hydrogen activation 135
Pd/CeO2, effect of S, diesel oxidation, a 105
Pd/graphite, hydrogen activation 135
Pd/La-Al2O3, catalytic combustion 11
Pd-LaCoO3, NO+H2+O2 164
Pd/La2O3, catalytic combustion 11
Pd/sepiolite, Heck reactions, a 105
hydrogenation of alkenes, a 105
preparation, using an ionic liquid, a 105
Pd/SiO2, 1-heptyne hydrogenation, a 175
hydrogenation 11
Pd/TiO2, inactivation of bacteria, a 226
Pd/ZrO2, effect of S, diesel oxidation, a 105
Pd-fullerite, 1-ethynyl-1-cyclohexanol hydrogenation, a 50
Pd-Pt/Al2O3, CH4 combustion 11
Pt/Pd, catalysed soot filter 27
diesel oxidation catalyst 27, 37
Pt/Pd/Au, diesel oxidation catalyst 37
Catalysts, Palladium Complexes, amphiphilic resin-
dispersion of Pd nanoparticles: aerobic oxidation
of alcohols, in H2O; hydrodechlorination of
chloroarenes, a 175
palladacycles, Buchwald-Hartwig amination 67
Heck, Sonogashira, Suzuki couplings 67
[Pd(μ-Br)(tBu3P)]2, alkyl thiols + aryl bromides 183
alkyl thiols + aryl iodides 183
aryl bromides + benzenethiol 183
aryl chlorides + amines 183
α-arylation of amides, esters 183
carbon–carbon bond formation 183
carbon–heteroatom coupling 183
characteristics 183
cyanation 183
handling 183
N-cyclohexylaniline + bromobenzene 183
N-methylaniline + 3-bromothiophene 183
O2 sensitivity 183
Suzuki coupling of sterically bulky aryl bromides 183
α-vinylation of esters, ketones 183
Pd enolate + DM-SEGPHOS, aldol reaction 203
α-fluorination reaction 203
Mannich reaction 203
Michael reaction 203
Pd(OAc)2 + BINAP, N-cyclohexylaniline +
bromobenzene 183
Pd(OAc)2 + tBu3P, N-cyclohexylaniline +
bromobenzene 183
Pd(OAc)2 + Xantphos, N-cyclohexylaniline +
bromobenzene 183
Pd particles/organic S ligands/phosphanes,
synthesis of cyclic vinyl sulfides, a 105
Pd particles/organic Se ligands/phosphanes,
synthesis of cyclic vinyl selenides, a 105
(tBu3P)Pd(0), from [Pd(μ-Br)(
tBu3P)]2 183
Catalysts, Platinum, Ba-K/Pt-Rh/A-ZT, NOx storage
and reduction 164
Ba-K/Pt-Rh/AZT, NOx storage and reduction 164
Catalysts, Platinum, (cont.)CO clean-up, in fuel processing 172
combustion, in fuel processing 172
diesel aftertreatment 179
electrocatalysts, Corich core-Ptrich shell/C, ORR, a 175
Pd-Pt/hollow core mesoporous shell C, for PEMFC 147
Pt, anodes, for PEMFC 147
sieve printed, for PEMFC, a 226
cathodes, for fuel cells 147
for MFC 147
for PEMFC 147
sieve printed, for PEMFC, a 226
for SOFC, a 226
electrodes, for PEMFC 147
spray printed, for PEMFC, a 226
MEAs, for PEMFC 147
for PEMFC 175, 219
Pt/C, anodes, for PEFC, a 51
cathodes, for DMFC 147
electrodes, for DEFC 147
Pt/Vulcan XC-72 C, cathodes, for PEFCs 58
Pt-Au, surface characterisation, by XPS 55, 109
Pt-Bi, formic acid oxidation 58
Pt3Ni, cathodes, for fuel cells 147
Pt-Pd/C, for DEFCs, a 51
PtRu, anodes, for DMFC 147
Pt-Ru, anodes, for PEFC 147
for PEM fuel cells 219
Pt-Ru/C, anodes, for DMFC 147
electrodes, for DEFC 147
Pt-Ru/Vulcan XC-72 C, anodes, for PEFCs 58
Pt-Sn, ethanol oxidation 58
Pt-Sn/C, electrodes, for DEFC 147
PtZn nanoparticles, for fuel cells, a 227
FePt-γ-CD, aqueous hydrogenations, a 226
Pd-Pt/Al2O3, CH4 combustion 11
production of H2SO4 40
Pt, catalysed soot filter 27
diesel oxidation catalyst 27
layer, diesel particulate filter 37
Pt/activated charcoal, hydrogen activation 135
Pt/Al2O3, by flame synthesis 11
by precipitation/impregnation 11
combustion of CO 164
enantioselective hydrogenation 11
Pt/γ-Al2O3, removal of soot and NOx, a 50
Pt/Al2O3 washcoat, diesel oxidation catalyst, a 226
Pt/(75% Al-21% BaCO3-2% K2CO3), NOx storage 164
Pt-Ba/Al2O3, lean NOx trap, regeneration with H2, a 50
Pt/Ba/Al2O3 washcoat, lean NOx trap 164
Pt/Ba/ZrO2/Al2O3, four-way catalyst 164
Pt/BaCO3/Al2O3, NOx storage-reduction 11
Pt/C, dissociative H2 chemisorption 135
Pt/C black, hydrogen activation 135
Pt/Ce-Pr-ZrOx, NOx storage 164
Pt/CeO2, NH3 storage 164
Pt/CeO2-Al2O3, NOx storage and reduction 164
Pt sintering 164
Pt/CexZr1–xO2, three-way catalyst 11
Pt/graphite, hydrogen activation 135
Pt/TiO2, inactivation of bacteria, a 226
oxidation 11
photocatalysis 11
Pt/WO3/ZrO2, NOx + H2, in O2-rich exhaust, a 175
Pt-Ni/alumina, oxidative steam reforming 147
Pt/Pd, catalysed soot filter 27
diesel oxidation catalyst 27, 37
Pt/Pd/Au, diesel oxidation catalyst 37
Pt-Rh/Al2O3, partial oxidation of CH4 11
Pt-Rh/Ba/Al2O3, NSR model catalyst, a 226
+ SCR catalyst, a 226
NOx abatement, a 226
PtSn2, selective hydrogenation, a 50
Catalysts, Platinum Complexes, activation of alkynes 86
amphiphilic resin-dispersion of Pt nanoparticles, a 175
Platinum Metals Rev., 2009, 53, (4) 234
Page Page
Catalysts, Rhodium, Ba-K/Pt-Rh/A-ZT, NOx storage
and reduction 164
Ba-K/Pt-Rh/AZT, NOx storage and reduction 164
exhaust gas reforming 221
Pt-Rh/Al2O3, partial oxidation of CH4 11
Pt-Rh/Ba/Al2O3, NSR model catalyst, a 226
+ SCR catalyst, a 226
NOx abatement, a 226
reforming, in fuel processing 172
Rh/Al2O3, selective hydrogenation 11
Rh/C, dissociative H2 chemisorption 135
hydrogenation of oximes 203
Rh/CexZr1–xO2, syngas production 11
Rh/cordierite monolithic honeycomb, reforming, a 175
Rh nanoparticles/zeolite, lean NOx–CO–H2, a 175
RhOx nanoparticles/zeolite, lean NOx–CO–H2, a 175
RhSn2, selective hydrogenation, a 50
Catalysts, Rhodium Complexes, H2 from alcohols 78
Rh BINAP, [2 + 2 + 2] cycloadditions, for preparation
of axial chiral aromatic compounds 203
Rh(CO)2(acac) + DiazaPhos-SPE, hydroformylation 203
Rh(dppe)]ClO4, addition of aldehydes across multiple
C–C, + C–H activation and C–C formation 86
Rh H8-BINAP, [2 + 2 + 2] cycloadditions, for
preparation of axial chiral aromatic compounds 203
Rh MandyPhosTM
, asymmetric hydrogenation 203
Rh Me-BoPhozTM
, reduction of α,β-enoic acids 203
Rh MonoPhosTM
, asymmetric hydrogenation 203
preparation of Aliskiren 203
Rh(nbd)2, P,N-complex; P,P-complex, asymmetric
reduction of (Z)-acetamidocinnamic acid
methyl ester 203
Rh(III) quinolyl-functionalised Cp, hydrogenation, a 50
Rh SEGPHOS®
, [2 + 2 + 2] cycloadditions, for
preparation of axial chiral aromatic compounds 203
Rh TangPhos, reduction of dehydroamino acids 203
reduction of enamides 203
reduction of itaconates 203
Rh–Xyl-PhanePhos, reduction of α,β-enoic acids 203
Catalysts, Ruthenium, electrocatalysts, PdRu
nanoparticles, anodes, for DMFC 147
PtRu, anodes, for DMFC 147
Pt-Ru, anodes, for PEFC 147
for PEM fuel cells 219
Pt-Ru/C, anodes, for DMFC 147
electrodes, for DEFC 147
Pt-Ru/Vulcan XC-72 C, anodes, for PEFCs 58
Ru/C, ammonia synthesis 135
RuSn2, selective hydrogenation, a 50
Catalysts, Ruthenium Complexes, asymmetric transfer
hydrogenation of ketones 203
bis(η5-2,4-dimethylpentadienyl)ruthenium(II) +
MandyPhosTM
, asymmetric hydrogenation 203
generation of H2, from alcohols 78
[HNEt3]+[(Ru{η5
-C5H5}{PPh3}2)2(PW12O40)]–
221
‘hydrogen borrowing’, for formation of C–C, C–N 86
monomeric, secondary alcohol racemisation 203
[RuCl2(P-Phos)(DMF)n], reduction of α,β-enoic acids 203
reduction of γ,δ-enoic acids 203
RuCl2[(R)-P-Phos][(S)-DAIPEN], aryl ketone reduction 203
RuCl2[(S)-xyl-P-Phos][(S)-DAIPEN], in synthesis of
imidazol[1,2-a]pyridine BYK-311319 203
RuCl3, dihydroxylation, in synthesis of Tamiflu®
, a 226
Ru–diamine, reduction of esters 203
Ru–DM-SEGPHOS®
, synthesis of sitagliptin 203
Ru MonoPhosTM
, reduction of carbonyl groups 203
Shvo catalyst, secondary alcohol racemisation 203
Ceramic Fusion Technique, PdAlRu alloys 189
Chemistry, a 52, 106, 176, 227
Chemotherapy Agents, for cancer, Pt salts 35
Chlorinated Ethenes, hydrodechlorination, a 105
Chloroarenes, hydrodechlorination, a 175
Chorine, corrosion of Pt, a 176
Cisplatin 35
Citral, vapour-phase selective hydrogenation, a 50
Colloids, Pd-Sn, inkjet printing, a 106
Combustion, catalytic 11
CH4 11
in fuel processing 172
Composites, Pt nanoparticle–graphene, a 51
Conferences, 32nd Annual Conference of Precious
Metals, U.S.A., 2008 40
Fuel Cells Science and Technology 2008, Denmark 147
Hydrogen Fuel Cells: For a Low Carbon Future, U.K.,
2008 78
5th International Conference on Environmental
Catalysis, Northern Ireland, 2008 164
18th International Solvent Extraction Conference,
U.S.A., 2008 100
Metals in Synthesis 2008, U.K. 86
Novel Chiral Chemistries Japan 2009 203
SAE 2008 World Congress, U.S.A. 37
22nd Santa Fe Symposium®, U.S.A., 2008 21
23rd Santa Fe Symposium®, U.S.A., 2009 198
The Taylor Conference 2009, U.K. 221
Corrosion, Pt, Cl2-induced, a 176
Coupling Reactions, C–C 183
C–heteroatom 183
palladacycle catalysts 67
Creep, Pt86:Al10:Z4, Z = Cr, Ir, Ru 2
CVD, precursors, Pd β-ketoiminates, a 227
Cyanation 183
Cycloaddition, [2 + 2 + 2], preparation of axial
chiral aromatic compounds 203
1,5,9-Cyclododecatriene, selective hydrogenation, a 50
Cyclododecene, from 1,5,9-cyclododecatriene, a 50
Defect Structure, polycrystalline Ir 138
Deformation, plastic, polycrystalline Ir 138
Dendrimers, G4.5-COOCH3 PAMAM, + Pd2+
, a 176
Dental, alloys, Pd-Ag-based 21
Pd74.0-In5.0-Cu14.5Ga1.6Sn4.9 21
Deuterium, permeation, Pd81Pt19 membrane, a 51
Diatomic Molecules, PtC, PtH, PtN, PtO, properties 123
Diesel, emissions control 27, 37, 164, 174, 179, 226
engines 179
exhaust gas mixtures, a 105
particulate matter, emissions, control 27
Diesel Oxidation Catalysts 27, 37, 105, 174, 179, 226
Diesel Particulate Filters 27, 37, 179
Dihydroxylation, olefins, a 50
in synthesis of Tamiflu®
, a 226
DMSO, solvent, a 176
Dynamic Kinetic Resolution, secondary alcohols 203
Elastic Constants, higher-order, Os, Ru 91
Electrical and Electronics, a 52, 106
Electrochemistry, a 106
preparation, of Pd nanorods, with high-index facets, a 106
Electrodeposition, CoPt nanowires, a 51
Electrodes, bottom, Ru, in DRAM capacitors, a 106
in Fuel Cells
Pd, EtOH oxidation, a 105
Pt, in dye sensitised solar cells 216
Electroless Plating, Cu, using a Pd-Sn catalyst, a 106
Pd films, on 316L stainless steel, a 52
Electroplating, Pd films, on 316L stainless steel, a 52
Emissions Control, a 50, 105, 175, 226
CO2 179
diesel 27, 37, 164, 174, 179, 226
gasoline 164, 179
motor vehicles, legislation, in Russia 98
vehicle 221
Engineering Stress-Strain Curve, Pd alloys 189
Engines, diesel 179
gasoline 179
αα,ββ-Enoic Acids, reduction 203
γγ,δδ-Enoic Acids, reduction 203
Enthalpy, PtC, PtH, PtN, PtO 123
Entropy, PtC, PtH, PtN, PtO 123
Platinum Metals Rev., 2009, 53, (4) 235
Page Page
Esters, α-arylation 183
reduction 203
α-vinylation 183
Ethane, steam reforming, a 175
Ethylene, adsorption, Pd-promoted zeolite 112
scavenger, Pd-promoted zeolite 112
1-Ethynyl-1-cyclohexanol, hydrogenation, a 50
Extraction, metals, conference 100
Films, FePt, oxidation behaviour, a 227
Pd, on 316L stainless steel, a 52
‘Final Analysis’ 55, 109, 179
Flame Spray Pyrolysis, one-step, nano-Pd/SiO2, a 175
Flame Synthesis, supported pgms 11
Formic Acid, electrooxidation, a 175, 227
fuel, for PEFC 58
generation of H2 78
oxidation 58
Four-Way Catalysts 27, 164
Fracture Strain, Pd alloys 189
PtRuGa 189
Fruit, climacteric, control of ethylene-induced ripening 112
Fuel Cells, a 51, 105, 175, 226–227
book reviews 172, 219
buildings 78
catalyst layers 219
catalysts, PtZn nanoparticles, a 227
cathodes, Pt, Pt alloys, DFT 147
conferences 78, 147
DEFC, electrocatalysts, a 51
electrodes, reaction mechanism, structural changes 147
DFAFC, anode catalysts, deactivation, reactivation, a 175
DMFC, anode catalysts 147
passive monopolar mini-stacks 147
portable electric power sources 147
vapour-fed 147
electrocatalysts 219
Pt-Au, surface characterisation, by XPS 55, 109
in Europe 78
fuel, processing 172
“Fuel Cell Today Industry Review 2009” 104
fuels 58, 78, 147, 172
membrane electrode assemblies 58
durability 147
MFC, anodes, cathodes, membranes 147
PEFC, anodes, electrocatalysts, a 51
Pt-Ru/Vulcan XC-72 C 58
cathodes, Pt/Vulcan XC-72 C 58
fuels, acetaldehyde, ethylene glycol, EtOH,
formaldehyde, formic acid, glycerol, MeOH,
1-propanol, 2-propanol 58
influence of NaCl vapour 147
liquid fuels 58
low pressure operation, using CO contaminated gas 147
MEAs, preparation 58
PEMFC, anodes 147
buildings 78
canal boat 78
catalyst layer degradation, XPS characterisation, a 175
catalyst layers 219
catalysts 147
cathode catalysts, using modelling aproach 147
CO-tolerant catalysts 219
electrocatalysts 219
electrodes 147
FlowCathTM
technology 147
H2 contamination, by Hg 147
high temperature 147
MEAs, by sieve printing method, a 226
by spray printing method, a 226
durability 147
reversal-tolerant catalyst layers 219
pgms, importance 40
SOFC, cathode, constant phase element, a 226
transport 78
Fuels, acetaldehyde 58
C-based 172
diesel 179
ethylene glycol 58
EtOH 58
formaldehyde 58
formic acid 58
gasoline 179
glycerol 58
H2, for fuel cells 58, 78, 147, 172
MeOH 58
processing 172
1-propanol 58
2-propanol 58
Gasoline, emissions control 164, 179
engines, downsized 179
Gibbs Energy, PtC, PtH, PtN, PtO 123
Glass, making, Pt equipment 40
Gluconic Acid, from glucose, a 50
Glucose, biosensor, a 227
selective oxidation, a 50
Grinding, Pt(5dpb)Cl, luminescence colour change, a 106
Hardness, Pd alloys 21, 189, 198
Pt 155, 198
Pt alloys 21, 155, 198
Heck Reactions, palladacycle catalysts 67
Pd/sepiolite, a 105
1-Heptyne, hydrogenation, a 175
1-Hexane, hydrogenation, a 50
High Temperature, Pt-based alloys 2, 69, 155
History, cisplatin, cancer drug 35
melting of Pt 209
Hydroacylation, alkenes, alkynes 86
Hydrocarbons, emissions, diesel 179
oxidation, in diesel exhaust, a 226
oxidative steam reforming 147
selective catalytic reduction 164
Hydrodechlorination, chlorinated ethenes, a 105
chloroarenes, in H2O, a 175
Hydroformylation, asymmetric 203
Hydrogen, absorption, Pd-Au nanoparticles, a 227
activation, Pd/C, Pt/C 135
borrowing, for formation of C–C, C–N 86
by exhaust gas reforming 221
by oxidative steam reforming 147
by photogeneration 45
+ CO, reduction of NOx, lean conditions, a 175
contamination, by Hg, for PEMFC 147
dissociative chemisorption, Pd/C, Pt/C, Rh/C 135
fuel, for fuel cells 58, 78, 147, 172
fuelling station requirements 78
generation 58, 78, 147
+ NO, + H2 164
photocatalysis 45
production 40
purification, Pd membranes 40
reduction, of NOx, on lean NOx traps, a 50
reduction of NOx, in O2-rich exhaust, a 175
sensors 147
storage 78
as NH3 147
uptake, Pd/activated C, a 176
vehicles 78
Hydrogen Peroxide, direct synthesis 221
Hydrogenation, alkenes, a 105
asymmetric 203
preparation of phenylalanines 203
in synthesis of sitagliptin 203
unsaturated C–C multiple bonds 203
asymmetric transfer, ketones 203
C5 olefin 221
catalyst additives 221
enantioselective, flame-made catalysts 11
Platinum Metals Rev., 2009, 53, (4) 236
Page Page
Hydrogenation, (cont.)1-ethynyl-1-cyclohexanol, a 50
flame-made catalysts 11
in H2O, a 226
1-heptyne, a 175
1-hexane, a 50
natural rubber latex, a 105
oximes 203
selective 11, 50
vapour-phase, citral, a 50
transfer 78
Hydrometallurgy, conference 100
Hydroprocessing, C supported catalysts 135
Imines, formation 86
reduction 203
Inkjet Printing, Pd-Sn colloids, a 106
Ionic Liquids, catalyst preparation, a 105
solvent, a 176
in solvent extraction 100
Iridium, arc melting 209
electron beam melting 209
melting 209
polycrystalline, defect structure 138
high purity 138
plastic deformation 138
single crystals 138
Iridium Alloys, Pt-Al-Ir, high temperature 2
Pt-10%Ir, investment casting 21
with Re and Ru 138
Iridium Complexes, dye sensitised solar cells 216
Ir(III), octahedral, photophysical properties 45
spectroscopic properties 45
OLEDs 45
Ir(III) fluorenone-ppy, electrophosphorescence, a 176
Ir(III) phenylpyridines, solar cells, a 52
Iridium Compounds, IrB1.35, hard, hardness, a 176
Jewellery, CAD/CAM 21, 198
mokume gane 198
Pd 198
Pd alloys 21, 189, 198
Pt, bench-scale repair, using blowpipes 209
lasers, manufacture, repair 21
manufacture 21, 198
Pt alloys 21, 189, 198
Johnson Matthey, autocatalyst production, Russia 98
catalysts 183, 203
ethylene scavanger 112
melting of Pt 209
“Platinum 2008 Interim Review” 48
“Platinum 2009” 174
ββ-Keto Esters, reduction 203
Ketones, aryl, reduction 203
asymmetric transfer hydrogenation 203
α-vinylation 183
Lasers, Pt jewellery, manufacture, repair 21
Lattice Misfits, Pt86Al10Z4, Z = Cr, Ir, Ru, Ta, Ti 69
Leaching, catalysts, for new catalytic reactions, a 105
Lean NOx Traps 37, 164
regeneration with H2, a 50
Liquid Crystals, palladacycles 67
Luminescence, colour change, grinding, Pt(5dpb)Cl, a 106
Pt octaethylporphyrin, a 51
Magnetism, CoPt nanowires, a 51
FePt-γ-CD, a 226
Markets, precious metals 40
MEAs, durability, in PEM fuel cells 147
preparation 58
Mechanical Properties, Pt-based ternary alloys 2
Melting, PdGaIn, arc melting, under Ar 198
pgms, history 209
Melting, (cont.)arc melting, electron beam heating, induction heating 209
Membranes, Pd, H2 purification 40
Pd81Pt19, D2 permeation, a 51
Metallurgy and Materials, a 51, 105–106, 176, 227
Metals Extraction, conference 100
Methane, + NO2 164
combustion 11
internal reforming 147
partial oxidation 11
steam reforming, a 175
Microwaves, synthesis of Pd-Pt/C, for PEMFC 147
Mokume Gane, jewellery 198
Nanocomposites, Pt nanoparticles/C MWNTs, a 227
Nanoflakes, Pd–PdO core–shell, on Pt, a 105
Nanoflowers, Pt, a 227
Nanoparticles, Corich core-Ptrich shell, a 175
FePt, a 226, 227
nano-Pd/SiO2, a 175
particulate matter 27
patchy, CdS/PdxCdyS/CdS, PdSx/Co9S8, a 106
Pd 50, 67, 105, 175, 176
PVP-protected, a 227
Pd on Au, a 105
Pd-Au, a 227
Pd-polymer (DNA) hybrid 147
PdRu 147
Pt, a 51, 175, 227
PtZn, a 227
Rh, a 175
RhOx, a 175
Nanorods, Pd, a 106
Nanowires, CoPt, a 51
Natural Gas, steam reforming, a 175
Nitrogen Oxides, NO, + H2, + O2 164
oxidation, in diesel exhaust, a 226
NO
2
, + CH4 164
NOx, control catalysts 27
emissions, diesel 164, 179
lean, reduction, by CO, H2, a 175
traps 37
regeneration with H2, a 50
reduction 50, 164
by H2, in O2-rich exhaust, a 175
removal, a 50
from diesel exhaust 221
under a lean/rich atmosphere, a 226
selective catalytic reduction 27, 179
storage 164
catalysts, model 164
storage-reduction 11
traps, diesel 179
lean 164
catalysts, S removal 164
thermal ageing 164
NMR,
31P, Pd(OAc)2 + dppf, a 106
NOx Storage and Reduction 164, 226
OLEDs, Ir(III), Os(II), Pt(II) complexes 45
Olefins, C5, hydrogenation 221
dihydroxylation, a 50
Osmium, higher-order elastic constants 91
sound velocity 91
ultrasonic attenuation coefficients 91
ultrasonic velocity 91
Osmium Complexes, Os(II), OLEDs 45
[Os(L–L)2(N–N)]2+
, phosphorescence, a 106
[Os(N–N)2(L–L)]2+
, phosphorescence, a 106
photoinduced electron-transfer 45
photoinduced energy-transfer 45
Oxidation, aerobic, alcohols, in H2O, a 175
by flame-made catalysts 11
CO, in diesel exhaust, a 226
electro-, EtOH, a 106
Platinum Metals Rev., 2009, 53, (4) 237
Page Page
Oxidation, (cont.)formic acid, a 175, 227
MeOH, a 227
EtOH 58, 105
FePt nanoparticles, a 227
formic acid 58
HC, in diesel exhaust, a 226
isothermal, Pt-Al-Z, Z = Cr, Ir, Re, Ru, Ta, Ti 2
Pt86:Al10:Z4, Z = Cr, Ir, Ru, Ti 2
MeOH, a 227
NO, in diesel exhaust, a 226
partial, CH4 11
particulate matter 27
Pt-based ternary alloys 2
selective, CO 11
glucose, a 50
Oximes, hydrogenation 203
Oxygen, + CO 221
reduction reaction, a 175
sensors, a 51
Palladacycles, anticancer 67
applications 67
catalysts, for cross-coupling reactions 67
characterisation 67
Hermann’s 67
liquid crystals 67
photophysical properties 67
synthesis 67
thermal stability 67
Palladium, electrodes, EtOH oxidation, a 105
films, electroless plated, on 316L stainless steel, a 52
electroplated, on 316L stainless steel, a 52
high temperature interface reaction, SiC, TiC, TiN, a 105
jewellery 198
melting 209
membranes, H2 purification 40
nanocrystalline, H2 uptake, a 176
nanoparticles 50, 67, 105
PVP-protected, a 227
nanorods, electrochemical preparation, a 106
with high-index facets, a 106
particles, dispersed over zeolite 112
Pd/activated C fibre, H2 uptake, a 176
Pd-on-Au nanoparticles, a 105
Pd nanoparticles/microporous activated C, H2 uptake, a 176
Pd–PdO core–shell nanoflakes, on Pt, a 105
Pd-polymer (DNA) hybrid nanoparticles, H2 sensors 147
Pd-promoted zeolite, ethylene adsorption 112
ethylene scavenger 112
Pd-Sn colloids, catalyst, electroless Cu metallisation, a 106
inkjet printing, a 106
Palladium Alloys, 950, burnishing, hardness, surface 198
investment casting 198
for jewellery 21, 189, 198
mokume gane 198
AuPdCu, fracture strain 189
hardness 189
tensile strength 189
yield strength 189
fusion of coloured ceramic overlays 189
hardness 21, 189, 198
investment casting 21, 198
jewellery 21, 189, 198
MgPd, from Mg6Pd, a 176
Mg6Pd, preparation, hydriding, a 176
Pd950G, Pd-Ga-Ag-In, casting 21
scrap, recycling 21
Pd-Ag-based, dental 21
950 Pd-Ag-Ga-Cu, casting 21
Pd95.5Al1.9Mg2.6, hardness 189
Pd95.5Al3.8Mg0.7, hardness 189
PdAlRu, mechanical behaviour 189
Pd95.5Al0.9Ru3.6, annealed, eng. stress-strain curves 189
XRD pattern 189
Palladium Alloys, (cont.)colour 189
density 189
fracture strain 189
hardness 189
Poisson’s ratio 189
ultimate tensile strength 189
workability 189
yield strength 189
Young’s modulus 189
Pd95.5Al2.8Ru1.7, annealed, eng. stress-strain curves 189
colour 189
density 189
fracture strain 189
hardness 189
Poisson’s ratio 189
ultimate tensile strength 189
workability 189
yield strength 189
Young’s modulus 189
Pd95.5Al0.4Ti4.1, hardness 189
Pd95.5Al1.3Ti3.2, hardness 189
Pd-Au nanoparticles, H2 absorption, a 227
PdCu, hardness 189
PdGa, hardness 189
PdGaIn, arc melting, under Ar 198
investment casting 198
Pd-In, thermochemistry, a 51
Pd74.0-In5.0-Cu14.5Ga1.6Sn4.9, dental 21
950 Pd-Nb-Ga 21
Pd81Pt19 membrane, D2 permeation, a 51
PdRu, fracture strain 189
hardness 189
tensile strength 189
yield strength 189
950 Pd-Ru-Ga, casting 21
Pd-Sn, thermochemistry, a 51
Pd-Zn, thermochemistry, a 51
watchmaking 189
Palladium Complexes, PCP-pincer Pd hydride–
K-Selectride®
, a 52
(PCP)i-Pr
PdCl + K-Selectride®
, a 52
Pd(II), recovery, from HCl, in presence of Pt(IV),
using S-containing monoamide, diamide 100
solvent extraction, pyridine carboxamide and
phosphonium ionic liquid systems 100
copolymers, N-isopropylacrylamide and thioethers 100
Pd(II) chloro, solvent extraction, tren polyamines 100
[Pd(dppf)(OAc)2], 31
P NMR, a 106
Pd(II) fluorinated benzoporphyrins, phosphorescence, a 106
Pd(II)-functionalised diphosphines, H2O soluble, a 176
Pd2+
+ G4.5-COOCH3 PAMAM dendrimers, a 176
Pd β-ketoiminates, CVD precursors, a 227
Pd(OAc)2 + dppf, 31
P NMR, a 106
Pd(OAc)2 + functionalised diphosphine, a 176
Pd(PPh3)2Cl2/ethylene-bridged dithiosemicarbazones, a 227
/phenylene-bridged dithiosemicarbazones, a 227
Pd(II) salicylaldimine dithiosemicarbazones, a 227
solvent extraction, using hydroxyoxime LIX 84I 100
using malonamide DMDOHEMA 100
tetrakis(triphenylphosphine)palladium, precusor, a 50
Palladium Compounds, MgD2, by hydrogentation, a 176
nanoparticles, patchy, CdS/PdxCdyS/CdS, PdSx/Co9S8, a106
palladacycles, see Palladacycles
Pd–PdO core–shell nanoflakes, on Pt, a 105
PdHx, destabilisation, a 176
Particles, nanosized, Zn2PtO4, a 51
Pd, dispersed over zeolite 112
Particulate Matter, emissions, diesel 27, 179
Patents 53–54, 107–108, 177–178, 228–229
Permeation, D2, Pd81Pt19 membrane, a 51
Phase Diagrams, Pt-Al-Co, Pt-Ni-Ru 155
Phenylalanines, by asymmetric hydrogenation 203
Phosphines, pgm complexes, in catalysis 203
Phosphorescence, electro-, Ir(III) fluorenone-ppy, a 176
Platinum Metals Rev., 2009, 53, (4) 238
Page Page
Phosphorescence, (cont.)Pt(II) fluorenone-ppy, a 176
NIR, Pd(II) with fluorinated benzoporphyrins, a 106
Pt(II) with fluorinated benzoporphyrins, a 106
[Os(L–L)2(N–N)]2+
, [Os(N–N)2(L–L)]2+
, a 106
Photocatalysis 11
Ru complexes 45
sterilisation of Escherichia coli, a 226
Photochemistry, pgm complexes 45
Photoconversion, a 52, 106, 176
Photophysical Properties, palladacycles 67
Photophysics, pgm complexes 45
Photoproperties, pgm complexes 45
Photosynthesis, ‘artificial’, Ru complexes 45
Platinum, arc melting 209
availability 40
coating, Si AFM probes, a 52
corrosion, Cl2-induced, a 176
electrodes, in dye sensitised solar cells 216
electron beam heating 209
equipment, glass industry 40
FePt film, oxidation behaviour, a 227
FePt nanoparticles, oxidation behaviour, a 227
hardness 155, 198
induction heating 209
industrial casting 209
jewellery, lasers, manufacture, repair 21
manufacture 21, 198
melting 209
nanoflowers, a 227
nanoparticles, a 51
Pd–PdO core–shell nanoflakes, on Pt, a 105
Pt nanoparticle–graphene composite, a 51
Pt nanoparticles/C MWNTs, glucose biosensor, a 227
segregation, in FePt nanoparticles, a 227
stress-rupture curve 2
thin films, on SiO2 particles, by barrel sputtering, a 52
ZGS, stress-rupture curve 2
Platinum Alloys, 950, burnishing, hardness, surface 198
investment casting 198
jewellery 21, 198
casting, effect of CAD/CAM-derived materials 21
colour 189
CoPt nanowires, electrodeposition, a 51
magnetic properties, microstructural properties, a 51
hardness 21, 155, 189
investment casting 21, 198
jewellery 21, 189, 198
Pd81Pt19 membrane, D2 permeation, a 51
Pt-Al, high temperature 2
Pt85:Al15, in situ high temperature TEM 69
Pt86Al14, Pt3Al precipitate, TEM 69
Pt-Al-Co, hardness 155
phase diagram 155
Pt-Al-Co-Cr-Ru, hardness 155
Pt-Al-Cr, high temperature 2
Pt86:Al10:Cr4, tensile testing 155
Pt79.5:Al10.5:Cr5.5:Ru4.5, Vickers hardness 155
Pt80:Al14:Cr3:Ru3 155
Pt80.5:Al12.5:Cr4.5:Ru2.5, Vickers hardness 155
Pt81.5:Al11.5:Cr4.5:Ru2.5, Vickers hardness 155
Pt83:Al11:Cr3.5:Ru2.5, Vickers hardness 155
Pt84:Al11:Cr3:Ru2, oxidation resistance 155
tensile testing 155
Pt84:Al11.5:Cr2.5:Ru2, Vickers hardness 155
Pt85:Al11:Cr2:Ru2, Vickers hardness 155
Pt-Al-Ir, high temperature 2
Pt86:Al10:Ir4, in situ high temperature TEM 69
stable precipitates 69
Pt-Al-Ru, high temperature 2
Pt86:Al10:Ru4, tensile testing 155
Pt-Al-Z, Z = Cr, Ir, Mo, Ni, Re, Ru, Ta, Ti, W 2
Pt-Al-Z, Z = Cr, Ir, Re, Ru, Ta, Ti, isothermal oxidation 2
Pt-Al-Z, Z = Cr, Ir, Ru, Ta, Ti, Pt3Al precipitate, TEM 69
TEM 69
Platinum Alloys, (cont.)Pt86:Al10:Z4, Z = Cr, Ir, Ru, stress-rupture curves 2
Pt86Al10Z4, Z = Cr, Ir, Ru, Ta, Ti, dislocation interactions 69
lattice misfits 69
precipitates 69
Pt-10%Ir, investment casting 21
Pt-Nb-Ru 2
Pt-Ni-Ru, phase diagram 155
Pt-Rh, stress-rupture curve 2
PtRu, colour 189
PtRuGa, fracture strain 189
hardness 189
tensile strength 189
yield strength 189
Pt-Ta-Re 2
Pt-Ta-Ru 2
Pt-Ti-Re 2
Pt-Ti-Ru 2
ternary, mechanical properties 2
oxidation 2
Platinum Complexes, in a chloride matrix, solvent
extraction, using Amberlite LA-2 100
[(COD)PtCl2] + LiN(SiMe3)2, a 52
[COD]PtClN(SiMe3)2, for PXP Pt pincer complexes, a 52
dye sensitised solar cells 216
Pt(II), OLEDs 45
square-planar, OLEDs 45
photochemistry 45
photophysics 45
Pt(IV), in HCl 100
Pt(II) chloro, solvent extraction, tren polyamines 100
[PtCl6]2–
, solvent extraction, using tripodal amido and
urea group-based anion-binding ligands 100
Pt–DNA adducts, a 227
Pt(dpb)Cl, luminescence colour change, grinding, a 106
Pt(5dpb)Cl, luminescence colour change, grinding, a 106
[Pt(dpma)Cl]+, substitution reaction with thioacetate, a 176
Pt(II) fluorenone-ppy, electrophosphorescence, a 176
Pt(II) fluorinated benzoporphyrins, phosphorescence, a106
Pt octaethylporphyrin, luminescence, a 51
O2-sensitive, a 51
[2(trenH4)4+·(PdCl4)
2–
·4Cl–
·H2O], isolation 100
Platinum Compounds, antitumour, a 227
cisplatin, anticancer drug 35
platinum salts, chemotherapy agents, for cancer 35
PtC, PtH, PtN, PtO, thermodynamic properties 123
PtCl4, from interaction of Cl2 with Pt(110), a 176
Pt silicide, formation, on Pt-coated Si AFM probes, a 52
Zn2PtO4, nanosized, a 51
Platinum Group Metals, analysis, using Analig®
40
demand, in autocatalysts, effect of CO2 legislation 179
melting 209
recycling 40
refining 40
Poisson’s Ratio, PdAlRu alloys 189
Precious Metals, conference: analysis, economics,
markets, process technologies, recovery, refining,
regulations, sampling 40
Propane, steam reforming, a 175
Racemisation, secondary alcohols 203
Recovery, Pd(II), from HCl, in presence of Pt(IV) 100
precious metals, from catalysts, plasma heater reactors 40
from combustible waste, using ‘The Ox’ 40
from refinery catalysts, by treatment in PlasmaEnvi®
40
Recycling, autocatalysts 40
Pd jewellery alloys 21
Reduction, aryl ketones 203
asymmetric, (Z)-acetamidocinnamic acid methyl ester 203
unfunctionalised alkenes 203
dehydroamino acids 203
enamides 203
α,β-, γ,δ-enoic acids 203
esters 203
imines 203
Platinum Metals Rev., 2009, 53, (4) 239
Page Page
Reduction, (cont.)itaconates 203
β-keto esters 203
NOx 164
with H2, a 50
Refining, JSC Krastsvetmet 40
Refining and Recovery, pgms 100
precious metals 40
Reforming, autothermal, C-based fuels 172
C-based fuels 172
exhaust gas 221
internal, CH4 147
oxidative steam, hydrocarbons 147
pre-, C-based fuels 172
steam, butane, a 175
C-based fuels 172
ethane, a 175
methane, a 175
natural gas, a 175
propane, a 175
Regulations, precious metals 40
Rhodium, arc melting 209
assaying 40
electron beam melting 209
high temperature interface reaction, SiC, TiC, TiN, a 105
melting 209
Rhodium Alloys, Pt-Rh, stress-rupture curve 2
Rhodium Complexes, photophysics 45
[(PNP)Rh(CN)] + EtI, a 52
[(PNP)Rh(CN)] + MeI, a 52
[(PNP)Rh(CN)(CH3)][I], reactions, a 52
Rh(III) bipyridines, photoproperties 45
Rh(III) chloro, solvent extraction, tren polyamines 100
Rh(III) cyclometallates, photoproperties 45
Rh(III) polypyridines, photoproperties 45
Rh(III) terpyridines, photoproperties 45
Rhodium Compounds, RhB1.1, hard, hardness, a 176
Rubber, natural latex, hydrogenation, a 105
Russia, new autocatalyst production facility 98
Ruthenium, bottom electrodes, in DRAM capacitors, a 106
chemical mechanical planarisation slurry, a 106
higher-order elastic constants 91
sound velocity 91
ultrasonic attenuation coefficients 91
ultrasonic velocity 91
Ruthenium Alloys, with Ir and Re 138
with Pd, see Palladium Alloys
with Pt, see Platinum Alloys
Ruthenium Complexes, ‘artificial photosynthesis’ 45
black dye, dye sensitised solar cells 216
CYC-B1, with an alkyl bithiophene group, solar cells, a 52
dendrimeric 45
dye sensitised solar cells 45, 216
K20 dye, dye sensitised solar cells 216
modified dyes, dye sensitised solar cells 216
multinuclear 45
N3 dye, dye sensitised solar cells 216
N719 dye, dye sensitised solar cells 216
photocatalysis 45
photogeneration, of H2 45
polymeric 45
Ru(III) chloro, solvent extraction, tren polyamines 100
Ru(II) polypyridines, basic properties 45
supramolecular assemblies 45
Ruthenium Compounds, RuO2·2H2O, RuO4, in Ru
chemical mechanical planarisation, a 106
Scavenger, Pd-promoted zeolite, of ethylene 112
Selective Catalytic Reduction, catalysts 37
CO 164
hydrocarbons 164
NH3 164
NOx 27, 179
Sensors, bio-, glucose, a 227
catalytic, precious metals 40
Sensors, (cont.)supported pgms, by flame synthesis 11
combustible gases 40
H2 147
O2, a 51
Single Crystals, iridium 138
Solar Cells, dye sensitised, Ir complexes 52, 216
Pt complexes 216
Ru complexes 45, 52, 216
Solvent Extraction, Pd, using hydroxyoxime LIX 84I 100
using malonamide DMDOHEMA 100
Pd(II), pyridine carboxamide and phosphonium ionic
liquid systems 100
copolymers of N-isopropylacrylamide and thioethers 100
Pd(II) chloro, using tren polyamines 100
Pt, in a chloride matrix, using Amberlite LA-2 100
[PtCl6]2–
, using tripodal amido and urea group-based
anion-binding ligands 100
Pt(II) chloro, using tren polyamines 100
Rh(III) chloro, using tren polyamines 100
Ru(III) chloro, using tren polyamines 100
Sonogashira Couplings, palladacycle catalysts 67
Soot, removal, a 50
Sound Velocity, Os 91
Ru 91
Specific Heat Capacity, PtC, PtH, PtN, PtO 123
Sputtering, barrel, Pt thin films, on SiO2 particles, a 52
reactive, of PdO, on Pt, a 105
Stress-Rupture, Pt 2
Pt86:Al10:Z4, Z = Cr, Ir, Ru 2
Pt-Rh 2
ZGS Pt 2
Sulfur, effect of, on diesel oxidation catalysts, a 105
removal, from lean NOx trap 164
Sulfuric Acid, production 40
Surface Coatings, a 52
Suzuki Couplings, palladacycle catalysts 67
sterically bulky aryl bromides 183
Syngas, production 11
Tamiflu
®®, synthesis, a 226
Thermochemistry, Pd-In, a 51
Pd-Sn, a 51
Pd-Zn, a 51
Thermodynamic Properties, PtC, PtH, PtN, PtO 123
Thin Films, Pt, on SiO2 particles, by barrel sputtering, a 52
Three-Way Catalysts 11, 27
Ultimate Tensile Strength, PdAlRu alloys 189
Ultrasonic Attenuation Coefficients, Os 91
Ru 91
Ultrasonic Velocity, Os 91
Ru 91
Vinyl Selenides, cyclic, synthesis, a 105
Vinyl Sulfides, cyclic, synthesis, a 105
αα-Vinylation, carbonyl compounds 183
esters 183
ketones 183
Watchmaking, Pd alloys 189
Water, remediation, hydrodechlorination, a 105
solvent, a 175, 176, 226
XPS, catalyst layer, PEM fuel cells, a 175
surface characterisation, heterogeneous catalysts 55, 109
Pt-Au fuel cell catalyst 55, 109
qualification of elements 109
Yield Strength, Pd alloys 189
PtRuGa 189
Young’s Modulus, PdAlRu alloys 189
Platinum Metals Rev., 2009, 53, (4) 240
Page Page
EDITORIAL TEAM
EditorDavid Jollie
Assistant EditorSara Coles
Editorial AssistantMargery Ryan
Senior Information ScientistKeith White
E-mail: [email protected]
Platinum Metals Review is the quarterly E-journal supporting research on the science and technology of the platinum group metals and developments in their application in industry
http://www.platinummetalsreview.com/
Platinum Metals ReviewJohnson Matthey Plc, Precious Metals Marketing, Orchard Road, Royston, Hertfordshire SG8 5HE, U.K.
E-mail: [email protected]://www.platinummetalsreview.com/