ORI GIN AL PA PER

Metal Clusters. As They Were Born in Siberia

Vladimir Fedorov

Received: 1 April 2014

� Springer Science+Business Media New York 2014

Abstract Key results of the researches in the field of cluster chemistry executed

by scientists of Nikolaev Institute of Inorganic Chemistry (NIIC) of the Siberian

Branch of Russian Academy of Sciences are presented. Structure and properties of

some cluster compounds of niobium, tantalum, molybdenum, tungsten and rhenium

for the first time synthesized in NIIC are briefly discussed. Some original results

which are conceptually important in chemistry of metal cluster complexes are noted.

Keywords Metal clusters � Niobium � Molybdenum � Rhenium � Chemical

modification � Condensation of cluster fragments

Introduction

The coordination chemistry of the transition metals always was one of the central

directions of chemical science. The main features of the coordination compounds

were formulated more than a century ago by Werner [1] and during long time this

classical work regularly served as the theoretical base of coordination chemistry.

However in the mid-sixties of the last century there came peculiar ‘‘crisis’’ of the

one-center Werner’s theory. Experimenters even more often found polynuclear

compounds with very short contacts between metal atoms. These facts demanded an

exit for a framework of one-center theory. In 1964 F. A. Cotton [2, 3] introduced the

term ‘‘metal atom cluster compounds’’ which defined groups of polynuclear metal

complexes with direct metal–metal bonds. From this point there is a keen interest in

V. Fedorov (&)

Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3,

Acad. Lavrentiev Prospect, Novosibirsk State University, 2, Pirogova St, Novosibirsk 630090,

Russian Federation

e-mail: fed@niic.nsc.ru

123

J Clust Sci

DOI 10.1007/s10876-014-0736-y

metal cluster complexes which keeps so far steady. Today we celebrate 50-year

anniversary of the cluster chemistry.

In anniversary days there is a natural desire to look back and to sum up some

results. In this article we present the studies on the transition metals cluster

complexes performed in Nikolaev Institute of Inorganic Chemistry of the Siberian

Branch of the Russian Academy of Sciences which from the very beginning actively

joined in development of the new scientific direction and made a significant

contribution to cluster chemistry.

In the present short contribution there is no possibility to comprehensively

present all researches executed by scientists of NIIC for last years in the field of

cluster chemistry. Therefore, the author had to focus only on some specific aspects

of chalcogenide and chalcohalogenide clusters that are closer to the author as to the

researcher. We will consider here only some key cluster systems of this type for the

first time synthesized at the Institute that are most characteristic representatives for

4d and 5d transition metals (Fig. 1).

First Studies: From Where Everything Came

Early studies of metal cluster compounds in NIIC were begun in Prof. A. Opalov-

sky’s laboratory at the beginning-sixties of last century: P. Samoylov, the student of

Novosibirsk State University (NSU), studied the chemistry of molybdenum

‘‘dibromide’’. As now we know, it is one of the most typical hexanuclear octahedral

cluster complex Mo6Br12 (it should note in brackets that at that time similar

compounds according to Brosset’s proposal called a staphyle [4]). In the monograph

‘‘Molybdenum halogenides’’ published in 1972 the certain head is devoted to the

staphyle complexes [5].

Studying Mo/Se and Mo/Te systems it was revealed that the lowest molybdenum

selenide and telluride had analytical composition of Mo3Q4 (Q = Se, Te) [6–8].

Later, using single crystal X-ray diffraction it was shown that crystal structures of

these binary chalcogenides contain an octahedral metal cluster and, therefore, they

should be described as Mo6Q8. This structural type can be considered as an ancestor

of the wide group of related ternary compounds MMo6Q8 (M = Pb, Sn and other

metals; Q = S, Se), which received in literature the name of ‘‘Chevrel phases’’ in

honor of the French PhD student R. Chevrel who synthesized the first compounds

with tin and lead [9]. These ternary chalcogenides were investigated very

intensively in connection with their superconducting properties: for that period of

time some compounds of this type showed critical temperatures about 15 K and

record-breaking critical fields (about 60 Teslas) [10]. Today the term ‘‘Chevrel

phases’’ was included in educational and encyclopedic editions, like Zintl phases,

Laves phases, etc.

In the same time, studying reactions of the lowest molybdenum halogenides with

chalcogens (executed by V. Fedorov under strong influence of the ideas of Prof.

S. Batsanov who was keen on synthesis of compounds with the mixed ligands, in

particular chalcohalogenides) led to opening of three-nuclear triangle complexes

Mo3Q7X4 (Q = S, Se; X = Cl, Br, I) [11, 12] (Fig. 1a). Probably, these polymeric

compounds having low reactivity and being insoluble in usual solvents would

V. Fedorov

123

remain unnoticed if ways of their transformation in molecular soluble forms were

not found. Pioneer works devoted to transformation of similar polymeric

compounds into soluble complexes were carried out by V. Fedin [13, 14]

(Fig. 2). The idea consisted in a breaking of bridged bonds in compounds with

polymeric structures by means of reactions of solids with strong nucleophilic

ligands. In such reactions the architecture and composition of the cluster core

{Mo3S7} were remained; examples of these reactions are given below:

[{Mo3S7}Cl2Cl4/2]? ? 2 PPh3 ? [{Mo3S7}Cl4(PPh3)2]

[{Mo3S7}Cl2Cl4/2]? ? 3 KS2P(OEt)2 ? [{Mo3S7}(S2P(OEt)2)3]Cl

The range of the depolymerization reactions was significantly expanded by M.

Sokolov, O. Gerasko and A. Gushchin by means of the application of mechano-

chemical activation of the processes [15]. Some of such reactions are given on

Fig. 3.

Later such processes of a depolymerization of metal cluster polymers received

the name as ‘‘excision reactions’’ of cluster core. These approaches opened a way to

wide-ranging studies of triangular chalcogenide clusters by solution chemistry.

These complexes were ancestors of the whole family of triangular cluster complexes

of molybdenum and the tungsten containing cluster cores {M3(l3-S)(l2-S2)3} and

{M3(l3-S)(l2-S)3}. So far in the world literature several hundred articles devoted to

structure and chemistry of similar complexes are published [16–21].

It is necessary to mention also a series of works on binuclear chalcogenide cluster

complexes of niobium, molybdenum and tungsten for which original methods of

synthesis were offered and their chemical properties were carefully studied (V.

Fedin, M. Sokolov, O. Gerasko [22, 23]). As an example, the developed scheme for

preparation of volatile binuclear niobium complexes Nb2S4L4 with organic ligands

Fig. 1 Examples of metal cluster complexes of different nuclearity discovered in NIIC

Metal Clusters

123

L is presented below. It consists of a chain of the consecutive transformations: (i)

high-temperature reaction of elements leading to formation of a cluster polymer

Nb2S4Br4; (ii) transformation of the polymeric compound Nb2S4Br4 to an anionic

complex in molten KSCN; (iii) obtaining an aquacomplex by an exchange of

terminal ligands SCN- in the course of acid hydrolysis and, at last, (iv) replacement

of water molecules by organic ligands with isolation of target compounds Nb2S4L4

(L = CH3COCHCOCH3-, CF3COCHCOCH3

-, CF3COCHCOC(CH3)3-, CF3COC

HCOCFC5F10-, CF3COCHCOC6H5

-, S2CN(C2H5)2-):

2Nbþ 4Sþ 2Br2 �!600�C

Nb2S4Br8=2 �!KSCN=190�CNb2S4f g SCNð Þ8

� �4�

�!Hþ

Nb2S4f g H2Oð Þ8g� �4þ�!þL

Nb2S4L4

Systematic studies of niobium chalcogenides and chalcohalogenides led to

discovery of tetrahedral metal cluster compounds Nb4Q4Y4 (Q = S, Se; Y = Br, I)

[24]. Though the phases of similar structure were obtained earlier for molybdenum

(C. Perrin [25]), synthesis of niobium compounds showed stability of this structural

type in strongly electron deficient systems (8 valence electrons per the tetrahedral

Nb4 cluster). Later this series was expanded by 12 electron rhenium thio telluride

Re4S4Te4 (Fig. 1b) (Y. Mironov, V. Fedin) [26].

potassiumdiethyldithiocarbamate

MeCN, reflux, 1 h

Fig. 2 Excision of cluster core {Mo3S7} from polymeric structure of triangle cluster complex[{Mo3S7}Cl2Cl4/2]? by reaction with diethyldithiocarbamate

Fig. 3 Scheme of preparation of soluble cluster complexes by mechanochemical activation of reactionsof solids

V. Fedorov

123

Re is the Most Abundant Cluster Element

In inorganic chemistry the rhenium is appeared to be one of the most abundant

cluster elements [27–35]. It is easily explained by the electronic reasons: Re3? ion

with the d4-electronic configuration in some inorganic compounds uses four valent

electrons for formation of metal–metal bonds, i.e. for a metal cluster formation. But

the ways of ‘‘utilization’’ of these electrons can be various: in binuclear halogenide

complexes [Re2X8]2- the d-electrons go to quadruple metal–metal bonds, while in

complexes [Re3X12]3- the triangular clusters with double Re = Re bonds are

formed. The same electrons suffice also for formation of octahedral metal cluster

complexes [Re6Q8X6]4- based on the trivalent rhenium where twelve two-centered

two-electron Re–Re bonds (on octahedron edges) are realized.

In rhenium cluster chemistry many discoveries were made in NIIC. For example,

synthesis of octahedral rhenium telluride Re6Te15 [36], chalcohalogenide complexes

Re6Q4X10 (Q = S, Se, Te; X = Cl, Br) [37, 38] and chalcocyanide ions

[Re6Q8(CN)6]4-/3- and [Mo6Q8(CN)6]7-/6- [39–43]. It should be noted that in

the field of the development of tetrahedral clusters [Re4Q4L12]4- (Re4?, d3-

electronic configuration) NIIC is a ‘‘monopolist’’ for a long time that can be

explained by subtleties of synthesis of such compounds. A breakthrough in

chemistry of the tetrahedral rhenium cluster complexes followed after successful

synthesis of key compounds [Re4Q4(TeX2)4X8] (Q = S, Se, Te; X = Cl, Br) by Y.

Mironov [44]. These compounds appeared fine precursors in various ligand

exchange reactions [31, 45] (Fig. 4).

Cluster Complexes as Building Blocks

Among various cluster compounds of molybdenum and rhenium the greatest

attention was paid to cyanide complexes [Mo6Q8(CN)6]6-/7-, [Re4Q4(CN)6]4-,

[Re6Q8(CN)6]4- and [Re12CS17(CN)6]6- possessing the terminal ambidentated CN

ligands. Nucleophilic nature of nitrogen atom of CN groups causes an ability of the

cyanide complexes to react with transition metal cations (cationic complexes) with

formation of polymeric cyano-bridged structures of the various types. These

nanosized complexes were widely used as building blocks in synthesis of

coordination polymers by Y. Mironov, N. Naumov, K. Brylev, S. Artemkina, O.

Efremova, M. Tarasenko [45–55]. Hundreds complex cluster coordination polymers

with chained, layered and framework structures, including chirality and porous

compounds were synthesized and characterized. Some examples of Re6 cluster

based polymers are presented in Fig. 5.

As a result of these studies, the approaches to control of processes of formation of

crystal structures of various dimensionalities by partial blocking of coordination

sites in metal complexes with competing ligands were found. The obtained data are

cornerstones of the directional design of cluster compounds with defined structures

and predicted properties.

Triangular aquacomplexes of type [{Mo3S4}(H2O)9] were used as building

blocks for preparation of the adducts with cucurbituriles of various compositions

and structures (V. Fedin, M. Sokolov, O. Gerasko (Fig. 6) [56]. Authors explained a

Metal Clusters

123

possibility of such reactions by formation of a system of complementary hydrogen

bonds between terminal aqualigands of triangular cluster complexes and oxygen

atoms of cucurbiturile.

ReCl5 + 4Q + 5Te Re4Q4(TeCl2)4Cl8 + TeCl4( Q = S, Se, Te)

+ (NH4)2Sx (H2O)+ KHF2, to

[{Re4Q4}F12]4-

Q=S, Se[{Re4Q4}(S3)4(S4)2]

4-

Q=Se, Te

[{Re4Q4}(CH3CONH)2Cl8]2-,

Q=S, Se[Re4Te4](DMF)4Cl8 [{Re4Q4}(SCN)12]

4-

Q=S, Se, Te

+DMF

+Pr4NCl +CH3CN +H2O +KCN (H2O)

+KSCN, to

[Re4Q4(CN12)]4-

Q=S, Se, Te

Fig. 4 Conversion of tetrahedral cluster compounds [Re4Q4(TeCl2)4Cl8] in reactions of different types

Fig. 5 Examples of coordination polymers based on cyanide octahedral metal cluster complexes

V. Fedorov

123

Chemical Modification of Cluster Complexes

In many cases the reactions of replacement of terminal ligands in cluster complexes

are trivial. However, some innovative approaches were offered in NIIC. It concerns,

first of all, the use of molten salts (KCN, KSCN, KOH, etc.) for ‘‘excision’’ of a

cluster core from polymeric structures resulting in soluble anionic complexes with

the terminal ligands introduced by these reagents—cyanides, hydroxides, etc. [39–

43, 57–59]. Another original approach is using of molten organic compounds as

sources of ligands in ligand exchange reactions (see, for example, [60–64]).

In contrast to replacement of terminal ligands, the situation with replacement of

ligands in a cluster core is not so obvious owing to high stability of the cluster core.

Studying of complexes of various types showed that replacement of inner ligands in

cluster core depends on ‘‘connectivity degree’’ of the ligand with metal cluster: as a

rule, l2-ligands are more labile in comparison with l3-ligands. It was shown that l2-

ligands in the cluster cores of three-nuclear molybdenum and tungsten complexes

{M3(l3-Q)(l2-Q2)3} can be involved in chemical modification. Furthermore, the

complexes containing l2-SSe ligands have strictly ordered positions of S and Se

atoms (V. Fedin, Y. Mironov, M. Sokolov, A. Gushchin) [65–67]. For example, two

unique complexes with different orientation of l2-SSe ligands relative to the M3

plane were prepared (Fig. 7).

In reaction of W3Te7Br4 with molten KSeNC (220 �C) a full series of triangular

complexes was prepared in cluster core of which l2-Te and l3-Te ligands were

succeeded to replace consistently by selenide ones [58] (Fig. 8).

In octahedral complexes the internal l3-ligands are rather stable. However, these

ligands can be also replaced at increased temperatures. For example, varying

experimental conditions in the reaction of Re6Se8Br2 with molten KOH the complex

with a cluster core {Re6Se4O4}2? was obtained. It is very interesting to note that in

this cluster core the selenium and oxygen atoms take strictly ordered positions

settling down in opposite planes of a pseudo-cube of Se4O4 (Fig. 9) [68].

Using high-temperature reactions l3-telluride ligands in a cluster core of rhenium

telluride {Re6(l3-Te)8}Te7 were replaced by selenium or sulfur with formation of

mixed ligand clusters {Re6Te8–xQx} (where Q = S or Se; 0 B x B 8) [69]. Between

the forms of different compositions a chemical equilibrium was observed:

Re6Te8f g $ Re6Te7Qf g $ Re6Te6Q2f g $Re6Te5Q3f g $ Re6Te4Q4f g $ Re6Te3Q5f g $Re6Te2Q6f g $ Re6TeQ7f g $ Re6Q8f g

It is known that in compounds with the mixed ligands there is the problem

connected with existence of an isomerism of a ligand environment. For example, in

quite simple Re–Te–Se system 22 cluster cores of different compositions {Re6Te8-x

Sex} (0 B x B 8) and their isomers exist. The isomers can be presented

simultaneously in the reaction mixture. All of them were found experimentally

using 125Te and 77Se NMR study [70, 71]. The obtained data, at their seeming

simplicity and evidence, nevertheless, are conceptual because they confirm that

fundamental laws of coordination chemistry are applicable to cluster complexes too.

Metal Clusters

123

{[W3S4(H2O)9](C36H36N24O12)}2+ {[W3(SbCl3)S4(H2O)9]2(C36H36N24O12)}

2+

Fig. 6 Structures of adducts of triangle cluster complex {W3S4(H2O)9} with cucurbiturile

Fig. 7 Structure of triangle cluster complex containing l2-SSe ligands with different orientation relativeto the M3 plane

W3Te7 W3Te4Se3 W3TeSe6 W3Se7

W3TeSe3 W3Se4

Fig. 8 Stepwise substitution of l2-Te and l3-Te ligands by Se atoms in cluster core {W3(l3-Te)(l2-Te)3}

V. Fedorov

123

These results are important not only as replenishment of fundamental knowledge in

the field of cluster chemistry, they are important also from the practical point of

view as a warn of the experimenters about difficulties on isolation of any individual

form from complex reaction mixture.

Crystallo-chemical similarity of chalcogenide ions (Q = S2-, Se2-) and

halogenide ions (Y = Cl-, Br-) allows to synthesize the chalcohalogenides

containing mixed (Q2-/Y-) ligands in a cluster core {M6Q8–xYx} [72]. Similar non-

isovalent replacements of ligands lead to change of a charge of a cluster core (for

example, {Re6Se8}2? ? {Re6Se4Br4}6?). Taking into account that external ligands

also can have various charge or to be neutral, cluster complexes are presented by a

rich range both cationic, and anion forms, including neutral molecular complexes as

it is shown below on the example of complexes on the basis of a cluster core

{Re6Se8}2?.

Cationic complexes: [Re6S8(H2O)6]2?, [Re6S8(NH3)6]2?;

Neutral complex: [Re6S8(H2O)4(OH)2]0

Anionic complexes: [Re6S8(H2O)2(OH)4]2-, [Re6S8Br6]4-

Chemical modification of cluster complexes by isovalent or non-isovalent

replacement of terminal and internal (l2- and l3-bridged) ligands including

substitution of metal atoms in cluster core is the convenient tool for thin control of

functional properties. So a variation of a ligand environment can change

luminescence properties of complexes, namely emission maximum wavelength,

quantum yield and life time. Systematic studies of luminescence properties of

octahedral cluster complexes of molybdenum and rhenium allowed obtaining

compounds with the improved characteristics. For example, the complexes

[Mo6I8(C3F7COO)6]2- and [Mo6I8(C:CC(O)OMe)6]2- show record quantum

yield values—0.59 and 0.18, respectively (M. Sokolov, K. Brylev [73, 74]).

Condensation of Cluster Fragments

One of topical issues of cluster chemistry is the problem of assembly of larger metal

clusters from cluster fragments. It was shown that using a method of condensation

Fig. 9 Structure of octahedralcluster complex[{Re6Se4O4}Cl6]4-

Metal Clusters

123

of triangular cluster fragments Re3 (proceeding from Re3Br9) it is possible to obtain

the complexes containing octahedral Re6 and bioctahedral Re9 clusters (S. Yarovoi)

(Fig. 10) [75]. Though the bioctahedral complex [Re9Se11Br6]2- turns out with a

small yield (that is explained by need to collect triangular fragments of different

composition in strict sequence), the result obtained confirms principle possibility of

similar progressive condensation of cluster fragments.

The Latest Discovery

There is two outstanding results obtained quite recently, namely, a synthesis of new

square clusters of vanadium and tantalum, V4S9Br4 and Ta4Q9X8, (Q = S, Se;

X = Br, I) (Fig. 1c) (Y. Mironov, V. Fedin, M. Sokolov, A. Gushchin [76, 77]), and

the unique twelve-nuclear rhenium complexes with the inserted carbon atom

[Re12CS17(CN)6]8-/6- (Y. Mironov, N. Naumov) (Fig. 1f) [78]. Their various

properties else should be investigated in details.

The reviews devoted chalcogenide cluster complexes of 4d and 5d transition

metals have been published recently [34, 45, 79].

The format of this short paper did not allow to state deeply all results obtained

during 50 years in NIIC in area of cluster chemistry. Today, looking back, it would

be desirable to note with great pleasure that Nikolaev Institute of Inorganic

Chemistry has collected under banners of cluster chemistry highly skilled, very

vigorous and inquisitive people. The names of the main persons were given in the

text, but, of course, it would be possible to expand significantly this list, having

included here numerous Russian and foreign coauthors from other institutes and

universities. It would be desirable to note especially our long-term and very fruitful

both scientific, and friendly cooperation with outstanding professors of cluster

science - Rosa Llusar Barelles (Universitat Jaume I, Spain), Arndt Simon (Max-

Planck-Instituite, Stuttgart, Germany), Dieter Fenske (Karlsruhe University, Ger-

many), Stephane Cordier, Christiane and Andre Perrin (University Rennes I),

Re3(in Re3Br9)

Re6(in [Re6Se8Br6]4–)

Re9 in [Re9Se11Br6]2–

Fig. 10 Example of synthesis of octahedral and bioctahedral cluster complexes by condensation oftriangle clusters

V. Fedorov

123

Sung-Jin Kim (Ewha Womans University, Korea), Noboru Kitamura (Hokkaido

University, Japan). To all of them a huge gratitude for the invaluable help and active

assistance.

References

1. A. Werner, Neuere Anschauungen auf dem Gebiete der anorganischen Chemie. F. Vieweg und Sohn:

Braunschweig, 1920, p.192.

2. F. A. Cotton and T. E. Haas (1964). Inorg. Chem. 3, 10.

3. F. A. Cotton (1964). Inorg. Chem. 3, 1217.

4. C. Brosset (1946). Arkiv. Kemi, Mineral. Geol. A22.

5. A. A. Opalovsky, I. I. Tychinskaya, Z. M. Kuznetsova, and P. P. Samoylov Molybdenum halogenides

(Science, Siberian Branch, Novosibirsk, 1972), pp. 98–109.

6. A. A. Opalovsky and V. E. Fedorov (1966). Neorg. Mater. (in Russian) 2, 443.

7. A. A. Opalovsky and V. E. Fedorov (1966). Neorg. Mater. (in Russian) 2, 447.

8. A. A. Opalovsky and V. E. Fedorov (1968). Neorg. Mater. (in Russian) 4, 293.

9. R. Chevrel, M. Sergent, and J. Prigent (1971). J. Solid State Chem. 3, 515.

10. Topics in Current Physics, Volume 32: Superconductivity in Ternary Compounds. Edited by O.

Fischer and M. B. Maple. Springer-Verlag: Berlin, Heidelberg, New York, 1982.

11. A. A. Opalovsky, V. E. Fedorov, and K. A. Khaldoyanidi (1968). Doklady Akad. Nauk. SSSR,

Chemistry (in Russian) 182, 1095.

12. A. A. Opalovsky, V. E. Fedorov, A. P. Mazhara, and I. M. Cheremisina (1972). Zh. Neorg. Khim. (in

Russian) 17, 2876.

13. V. P. Fedin, S. P. Gubin, A. V. Mishchenko, and V. E. Fedorov (1984). Koord. Khim. (in Russian) 10,

901.

14. V. P. Fedin, M. N. Sokolov, Y. V. Mironov, B. A. Kolesov, S. V. Tkachev, and V. Y. Fedorov

(1990). Inorg. Chim. Acta 167, 39.

15. V. V. Volkov, K. G. Myakishev, M. N. Sokolov, V. P. Fedin, A. L. Gushchin, and E. A. Il’ınchik

(2005). Chem Sustain Dev 13, 155.

16. R. Hernandez-Molina, M. N. Sokolov, and A. G. Sykes (2001). Acc. Chem. Res. 34, 223.

17. R. Llusar, and S. Uriel (2003). Eur. J. Inorg. Chem., 1271.

18. R. Llusar and C. Vicent (2010). Coord. Chem. Rev. 254, 1534.

19. M. N. Sokolov and P. A. Abramov (2012). Coord. Chem. Rev. 256, 1972.

20. E. Cadot, M. N. Sokolov, V. P. Fedin, C. Simonnet-Jegat, S. Floquet, and F. Secheresse (2012).

Chem. Soc. Rev. 41, 7335.

21. M. N. Sokolov, R. Hernandez-Molina, and P. A. Abramov, Molybdenum: Its Biological and Coor-

dination Chemistry and Industrial Applications. Edited by A. Holder. The University of Southern

Mississippi: Hattiesburg, MS, USA, 2013, pp. 105-140.

22. V. E. Fedorov, V. P. Fedin, and O. A. Kuzmina (1986). Koord. Khim. (in Russian) 12, 1077.

23. M. Sokolov, O. Gerasko, A. Virobets, V. Fedorov, and K. Hegetschweiler (1998). Inorg. Chim. Acta

271, 222.

24. V. E. Fedorov, V. K. Evstafev, S. D. Kirik, and A. V. Mishchenko (1981). Zh. Neorg. Khim. (in

Russian) 26, 2701.

25. C. Perrin, R. Chevrel, and M. Sergent (1975). Compt. Rend. 281, 23.

26. V. E. Fedorov, Y. V. Mironov, V. P. Fedin, and Y. I. Mironov (1994). J. Struct. Chem. 35, 146.

27. A. Perrin, C. Perrin, and M. Sergent (1988). J. Less-Common Met. 137, 241.

28. Y. V. Mironov and V. E. Fedorov (1999). J. Struct. Chem. 40, 959.

29. T. Saito (1999). J. Chem. Soc., Dalton. Trans., 97.

30. J. C. P. Gabriel, K. Boubekeur, S. Uriel, and P. Batail (2001). Chem. Rev. 101, 2037.

31. Y. V. Mironov and V. E. Fedorov (2002). Russ. Chem. Bull. 51, 569.

32. T. G. Gray (2003). Coord. Chem. Rev. 243, 213.

33. R. A. Walton (2004). J. Cluster Sci. 15, 559.

34. V. Y. Fedorov, Y. V. Mironov, N. G. Naumov, M. N. Sokolov, and V. P. Fedin (2007). Russ. Chem.

Rev. 76, 529.

Metal Clusters

123

35. Multiple Bonds between Metal Atoms. Third Edition. Edited by F. A. Cotton, C. A. Murillo, R.

A. Walton. Springer: New York, 2005.

36. V. E. Fedorov, N. V. Podberezskaya, A. V. Mischenko, G. F. Khudorozko, and I. P. Asanov (1986).

Mater. Res. Bull. 21, 1335.

37. A. A. Opalovsky, V. E. Fedorov, and E. U. Lobkov (1971). Zh. Neorg. Khim. (in Russian) 16, 1494.

38. A. A. Opalovsky, V. E. Fedorov, E. U. Lobkov, and B. G. Erenburg (1971). Zh. Neorg. Khim. (in

Russian) 16, 3175.

39. Y. V. Mironov, A. V. Virovets, V. E. Fedorov, N. V. Podberezskaya, O. V. Shishkin, and Y.

T. Struchkov (1995). Polyhedron 14, 3171.

40. A. Slougui, Y. V. Mironov, A. Perrin, and V. E. Fedorov (1995). Croat. Chem. Acta 68, 885.

41. N. G. Naumov, A. V. Virovets, N. V. Podberezskaya, and V. E. Fedorov (1997). J. Struct. Chem. 38,

857.

42. Y. V. Mironov, A. V. Virovets, N. G. Naumov, V. N. Ikorskii, and V. E. Fedorov (2000). Chem. Eur.

J. 6, 1361.

43. K. A. Brylev, A. V. Virovets, N. G. Naumov, Y. V. Mironov, D. Fenske, and V. E. Fedorov (2001).

Russ. Chem. Bull. 50, 1140.

44. Y. V. Mironov, T. E. Albrecht-Schmitt, and J. A. Ibers (1997). Inorg. Chem. 36, 944.

45. O. A. Efremova, Y. V. Mironov, and V. E. Fedorov (2006). Eur. J. Inorg. Chem., 2533.

46. N. G. Naumov, A. V. Virovets, and V. E. Fedorov (2000). J. Struct. Chem. 41, 499.

47. V. E. Fedorov, N. G. Naumov, Y. V. Mironov, A. V. Virovets, S. B. Artemkina, K. A. Brylev, S.

S. Yarovoi, O. A. Efremova, and U. H. Peak (2002). J. Struct. Chem. 43, 669.

48. K. A. Brylev, Y. V. Mironov, N. G. Naumov, V. E. Fedorov, and J. A. Ibers (2004). Inorg. Chem. 43,

4833.

49. Y. V. Mironov, N. G. Naumov, K. A. Brylev, O. A. Efremova, V. E. Fedorov, and K. Hegetschweiler

(2004). Angew. Chem., Int. Ed. 43, 1297.

50. K. A. Brylev, G. Pilet, N. G. Naumov, A. Perrin, and V. E. Fedorov (2005). Eur. J. Inorg. Chem.,

461.

51. Y. V. Mironov, N. G. Naumov, K. A. Brylev, O. A. Efremova, V. E. Fedorov, and K. Hegetschweiler

(2005). Russ. J. Coord. Chem. 31, 269.

52. Y. V. Mironov, N. G. Naumov, S. J. Kim, and V. E. Fedorov (2007). Russ. J. Coord. Chem. 33, 279.

53. Y. Kim, V. E. Fedorov, and S. J. Kim (2009). J. Mater. Chem. 19, 7178.

54. K. A. Brylev, N. G. Naumov, A. V. Virovets, S.-J. Kim, and V. E. Fedorov (2009). J. Cluster Sci. 20,

165.

55. M. S. Tarasenko, E. O. Golenkov, N. G. Naumov, N. K. Moroz, and V. E. Fedorov (2009). Chem.

Commun., 2655.

56. O. A. Gerasko, M. N. Sokolov, and V. R. Fedin (2004). Pure Appl. Chem. 76, 1633.

57. S. S. Yarovoi, Y. V. Mironov, D. Y. Naumov, Y. V. Gatilov, S. G. Kozlova, S. J. Kim, and V.

E. Fedorov (2005). Eur. J. Inorg. Chem., 3945.

58. M. N. Sokolov, P. A. Abramov, A. L. Gushchin, I. V. Kallnina, D. Y. Naumov, A. V. Virovets, E.

V. Peresypkina, C. Vicent, R. Llusar, and V. P. Fedin (2005). Inorg. Chem. 44, 8116.

59. K. A. Brylev, Y. V. Mironov, S.-J. Kim, and V. E. Fedorov (2007). J. Struct. Chem. 48, 1118.

60. Y. V. Mironov, M. A. Shestopalov, K. A. Brylev, S. S. Yarovoi, G. V. Romanenko, V. E. Fedorov, H.

Spies, H.-J. Pietzsch, H. Stephan, G. Geipel, G. Bernhard, and W. Kraus (2005). Eur. J. Inorg. Chem.,

657.

61. Y. V. Mironov, K. A. Brylev, M. A. Shestopalov, S. S. Yarovoi, V. E. Fedorov, H. Spies, H.-J.

Pietzsch, H. Stephan, G. Geipel, G. Bernhard, and W. Kraus (2006). Inorg. Chim. Acta 359, 1129.

62. M. A. Shestopalov, Y. V. Mironov, K. A. Brylev, S. G. Kozlova, V. E. Fedorov, H. Spies, H.-J.

Pietzsch, H. Stephan, G. Geipel, and G. Bernhard (2007). J. Am. Chem. Soc. 129, 3714.

63. M. A. Shestopalov, Y. V. Mironov, K. A. Brylev, and V. E. Fedorov (2008). Russ. Chem. Bull. 57,

1644.

64. M. A. Shestopalov, S. Cordier, O. Hernandez, Y. Molard, C. Perrin, A. Perrin, V. E. Fedorov, and Y.

V. Mironov (2009). Inorg. Chem. 48, 1482.

65. V. P. Fedin, Y. V. Mironov, M. N. Sokolov, B. A. Kolesov, V. Y. Fedorov, D. S. Yufit, and Y.

T. Struchkov (1990). Inorg. Chim. Acta 174, 275.

66. R. Hernandez-Molina, M. Sokolov, P. Nunez, and A. Mederos (2002). J. Chem. Soc., Dalton. Trans.,

1072.

67. A. L. Gushchin, B. L. Ooi, P. Harris, C. Vicent, and M. N. Sokolov (2009). Inorg. Chem. 48, 3832.

V. Fedorov

123

68. S. S. Yarovoi, Y. V. Mironov, S. F. Solodovnikov, D. Y. Naumov, N. K. Moroz, S. G. Kozlova, A.

Simon, and V. E. Fedorov (2005). Chem. Commun., 719.

69. V. E. Fedorov, Y. I. Mironov, Y. V. Mironov, N. G. Naumov, U. H. Peak, and S. C. Shin (1998).

Russ. J. Inorg. Chem. 43, 1786.

70. Y. V. Mironov, J. A. Cody, T. E. AlbrechtSchmitt, and J. A. Ibers (1997). J. Am. Chem. Soc. 119,

493.

71. V. E. Fedorov, S. V. Tkachev, N. G. Naumov, Y. V. Mironov, and Y. I. Mironov (1998). Russ.

J. Inorg. Chem. 43, 1562.

72. S. S. Yarovoi, Y. I. Mironov, Y. V. Mironov, A. V. Virovets, V. E. Fedorov, U. H. Paek, S. C. Shin,

and M. L. Seo (1997). Mater. Res. Bull. 32, 1271.

73. M. N. Sokolov, M. A. Mihailov, E. V. Peresypkina, K. A. Brylev, N. Kitamura, and V. P. Fedin

(2011). Dalton Trans. 40, 6375.

74. M. N. Sokolov, M. A. Mikhailov, K. A. Brylev, A. V. Virovets, C. Vicent, N. B. Kompankov, N.

Kitamura, and V. P. Fedin (2013). Inorg. Chem. 52, 12477.

75. V. E. Fedorov, M. R. J. Elsegood, S. S. Yarovoi, and Y. V. Mironov (1998). Chem. Commun., 1861.

76. Y. V. Mironov, S. S. Yarovoi, D. Y. Naumov, S. G. Kozlova, V. N. Ikorsky, R. K. Kremer, A. Simon,

and V. E. Fedorov (2005). J. Phys. Chem. B. 109, 23804.

77. M. N. Sokolov, A. L. Gushchin, P. A. Abramov, A. V. Virovets, E. V. Peresypkina, S. G. Kozlova, B.

A. Kolesov, C. Vicent, and V. P. Fedin (2005). Inorg. Chem. 44, 8756.

78. Y. V. Mironov, N. G. Naumov, S. G. Kozlova, S. J. Kim, and V. E. Fedorov (2005). Angew. Chem.,

Int. Ed. 44, 6867.

79. M. N. Sokolov, N. G. Naumov, P. P. Samoylov, and V. P. Fedin Clusters and Cluster Assemblies. in

J. Reedijk and K. Poeppelmeier (eds.), Comprehensive Inorganic Chemistry II (Second Edition)

(Elsevier, Amsterdam, 2013), pp. 271–310.

Metal Clusters

123