synthesis and some reactions of tris (pentafluorophenyl) antimony compounds

252 PREM RAJ et al.

by standard methods. Freshly prepared metallic salts except NaN3, were dried in vucuo before use.

All solvents were purified and dried by standard procedures and reactions were carried out under anhydrous conditions.

IR spectra were recorded in the range 4000-200 cm - 1 by using KBr/CsI pellets on a Perkin-Elmer 577 spectra-photometer. The molar conductance of 10T3 M solutions was determined at 25°C with a Phillips Conductivity assembly PR-9500. Molecular weight was determined cryoscopically in benzene using a Beckmann thermom- eter of accuracy of f 0.0 1 OC.

Typical experimental details of the reactions are described below. Relevant IR assignments, analytical data and molar conductance values are listed in Tables l-2.

min to ensure complete reaction. Concentration of the solution followed by the addition of petroleum- ether (bp. 60-80%) afforded off white crystalline solid, tris(pentafluoropheny1) antimony (V) chloride iodide, m.p. 165-66%.

Similarly, 1: 1 molar reaction of tris(pentafluorophenyl) antimony (1.246 g, 2 mmol) and iodine monohromide (0.414 g, 2 mmol) yielded tris(pentafluoropheny1) antimony(V) bromide iodide, m.p. 126%.

Reaction of (C6Fs),Sb with IN3 and INCO, (III, IV). A freshly generated solution of iodine azide (0.338 g, 2 mmol) in acetonitrile (50 cm3) at - 10°C was added to a precooled (- 10°C) vigorously stirred solution of tris(pentafluoropheny1) antimony (1.246 g, 2 mmol) in the same solvent (50 cm’) during 15 min under nitrogen atmosphere. The reactants were stirred for 1 hr at initial temperature and then allowed to come at room temperature. The solution was evaporated under reduced pressure and cooled overnight, after adding petroleum-ether (bp. 40-60°C) (10 cm3). A pale yellow crystalline solid thus obtained was characterised as tris(pentafluorophenyl)antimony azide iodide (III), m.p. 26OOC.

(C6F5),SbINC0 (IV) was obtained as a white crystalline solid by the method described above by

Oxidative addition reactions Reaction of(CsFS)3Sb with ICI and IBr, (I, II). A

solution of iodine monochloride (0.325 g - 2 mmol) in acetonitrile (40 cm3) was added dropwise to a stirred solution of tris(pentafluorophenyl)antimony (1.246 - 2 mmol) in the same solvent (50 cm’) at -5OC during 1 hr. The reactants were allowed to attain room temperature and stirred further for 30

Table 1. Analytical data of tris(pentafluorophenyl)antimony(V) derivatives

S.No. Compound Colour m.p. YieAd (Ohm-' cm*

(Oc) ($1 mo1o-'Ifor Analysis Pound(Calod)

,o-3n eo1u- tian in .ac*-

C H N Sb

(C6F5)3SbIC1

(C6F5)3SbIBr

(C6F5)3SbrN3

(C6F5)3SbINC0

(C6F5)3Sb(NCS)2

(C6F5)3SbS

E(C6F5)3Sb}20] ("'312

Brown 165-66 62

Brow 126 70

Pale 260(d) 56 yellow

uhits 62 62

32.37

34.80

26.21

brownish 205(d) 74 yellow

16.42

Off white 122 60

white 280(d) 65 13.02

(C6F5)3Sb(NCO)2 uhits 250(d) 70 16.00

27.35 (27.53)

i5.42 (15.50)

14.56 (14.6'7)

26.00 (26.05)

27.22

(27.30)

1 .72

(1 076)

3.60

(3.7 9)

5.63 (6.24)

3.62

(3.96)

38.06 0.92 3.36 (36.12)

14.80 (0.9e) (3.42) (14.86)

40.01 (40.23)

0.62

(0.64) 2.62

(2.93) (:: :“,‘9, 37.49 (37.57)

45.62 (45.62)

3.36 (3.65) (:E)

13.26 (13.67)

white 245 68 18.42

20.20 white 210 70

m-Bits 196 60 ‘8.92

white 55 55 ‘9.40

Reactions of tris(pentafluorophenyI)antimony compounds 253

Table 2. Relevant IR absortions of the anions in tris(pentafluorophenyl)antimony(V) compounds (cm-‘)

III IV v VII VIII IX X XI XII ASSIGNMENTS

21SOl.n 2lSOm

1275m 123Ow

665u 6OEm

572sh

568ma

2OSSmbr 218Om

760 129Ou 84OVW

2160mbr -

C

47Sm 625~ 62% -

1700s

36Sma

1235m

415w

a I Overlapped by C6FS absorptions; li = In CHC13 solution: c - Absent

Q= weak, ml fledium, br P Broad, s = Strong. Sh - shoulder, vu = very weak

16SSm - 1 6E2mb

1310mb - 13lOm

1 632ma

915m

5OSW 48Sw

2920m 2 920m

9 asy (NCX)

$ (c-x) SY

S (N3/~Cx 1

ts, (co/oco)

1 63Sma

92Sm

46Ow

3 (C=N)

3 (N-O)

9 (Sb-0)

+(Sb-N)

2925m 3 (C-H)

employing an equimolar ratio of the corresponding reactants, m.p. 82°C.

Reaction of (C6F,),Sb with (SCN),, (V). A freshly prepared solution of thiocyanogen (0.25 g, 2 mmol) in CCl,,(30cm3) was added to a stirred tris(pentafluoropheny1) antimony (1.246 g, 2 mmol) solution in CC1,(50 cm3) at -5°C during 15 min. The reaction mixture was subsequently stirred for 1 hr and warmed to room temperature. The removal of the volatiles under reduced pressure afforded a pale yellow solid. After re- crystallisation from ethanol it was characterised as tris(pentafluorophenyl)antimony diisothiocyanate (V), m.p. 205°C (d).

Reaction of (C,F,),Sb with suiphur, (VI). A solution of tris(pentafluorophenyl)antimony (1.246 g, 2 mmol) in acetonitrile (50 cm’) was refluxed with elemental sulphur (0.064 g, 2 mmol) for 1 hr under nitrogen atmosphere. The solution was concentrated and cooled overnight to afford off-white crystalline solid. It was character&d as tris(pentafluorophenyl)antimonysulphide (VI), m.p. 122OC.

The same product (VI) was obtained when the reaction was repeated in benzene as solvent.

(ii) Metathetical reactions Reaction of (C~F&SbClr with AgSCN and

KNCO, (V and VIII). Tris(pentafluorophenyl)antimony dichloride (1.3888 g, 2 mmol), and silver

thiocyanate (0.464 g, 4 mmol) were stirred together in benzene (100 cm3) at room temperature for 3 hr and then refluxed for 1 hr to ensure completion of the reaction. Silver chloride was filtered off and concentration of the solution under reduced pressure followed by the addition of petroleum*ther (bp. 40-60%) yielded off-white crystalline tris(pentafluoropheny1) antimony diisothiocyanate (V), m.p. 205OC.

Similarly, 1 : 2 molar reaction of tris(pentafluorophenyl)antimony(V) dichloride (1.388 g, 2 mmol) and potassium cyanate (0.324 g, 4 mmol) was found to give tris(pentafluorophenyl)antimony(V) diisocyanate, m.p. 250°C (d).

Reaction of (C6FS)3SbC12 with NaN,, (VII). An aqueous solution of sodium azide (0.264 g, 4 mmol) was added to an ethereal solution of tris(pentafluorophenyl)antimony dichloride (1.3888.2 mmol) and the mixture was stirred for 3 hr at room temperature. The ether layer was separated and dried over sodium sulphate. It was then evaporated and cooled to yield off-white crystalline solid which was characterised as oxybis(tris(pentafluorophenyl)antimony)diazide (VII), m.p. 280%.

Reaction of (C6Fs)3SbICl with KNCO, (IV). A suspension of potassium cyanate (1 g, 1.24 mmol) in acetonitrile was added to a solution of tris(pentatluorophenyl)antimony chloride iodide (0.785 g, 1 mmol) in the same solvent (60 cm’) and refluxed for 3-4 hr. The mixture. was then filtered

254 PREM RAJ et al.

to remove potassium chloride and uureacted potassium cyanate. The filtrate was concentrated under vacuum to afford white solid, which was recrystallised from petroleum-ether (bp. 40-60%) and characterised as tris(pentafluorophenyl)anti- many(V) iodide isocyanate, m.p. 82°C.

The similar procedure as described above was adopted to obtain tris(pentafluorophenyl)anti- many(V) iodide azide from tris(pentafluorophenyl)antimony chloride iodide (0.785 g, 1 mmol) and sodium azide (0.08 g, 1.23 mmol). Compounds (III) and (IV) may also be prepared by the reaction of tris(pentafluorophenyl)antimony bromide iodide with the corresponding metallic salt.

Preparation of tris(pentaJluorophenl)antimony disubstituted amide, -oximate and carboxylate derivatives (IX, X-XII). In a typical experiment tris(pentalluorophenyl)antimony dichloride (0.694 g, 1 mmol) and sodium succinimide (0.238 g, 2 mmol) in benzene (60 cm’) was stirred at room temperature for 3 hr. Sodium chloride was filtered off and the filtrate was concentrated under vacuum followed by the addition of n-hexane (10 cm3) and on scratching yielded a white solid. It was recrystallised from petroleum-ether (bp. 40-60%) and characterised as tris(pentafluorophenyl)antimony disuccinimide (IX) m.p. 24Y’C.

Compounds (X)-(XII) were synthesised from tris(pentafluorophenyl)antimony dichloride and the corresponding sodium salt of oxime or carboxylate in 1 : 2 molar ratio, respectively.under conditions similar to those described for the disuccinimide.

(iii) Reductive cleavage reactions Reaction of (C6FS)3SbS with ArsPbz(l : 1). To

an acetonitrile solution (50 cm’) of tris(pentafluorophenyl)antimony sulphide (0.652 g, 1 mmol) hexaphenyldilead (0.876 g, 1 mmol) in the same solvent (30 cm’) was added and stirred for 3 hr at room temperature. The solution was concentrated and petroleum-ether (bp. 60-80°C) was added to precipitate a white crystalline solid characterised as bis(triphenyllead) sulphide, m.p. 140-141°C (lit,14 m.p. 139-143OC). After filtering the precipitate, the filtrate was concentrated and cooled to yield off-white crystals of tris(pentafluorophenyl)antimony m.p. 74OC (lit.,4 m.p. 74OC).

Similarly, reaction of tris(pentaiIuoropheny1) antimony sulphide with hexa-p-tolyl dilead produced bis(tri-p-tolyllead) sulphide m.p. 143-144OC (lit.,14 m.p. 144OC) and tris(pentafluorophenyl)- antimony, m.p. 74OC (lit.,4 m.p. 74OC).

Reaction of (C,F,),Sb(NCO), with P&Pb, (1: 1). To a refluxing solution of hexaphenyl dilead (0.876 g; 1 mmol in chloroform (50 cm3)

was added dropwise a chloroform solution of tris(pentafluorophenyl)antimony diisocyanate (0.707 g, 1 mmol). The reactants were refluxed for 5 hr and then cooled at ice temperature. The solid thus separated was filtered off and identified as diphenyllead diisocyanate m.p. 230-235°C (d). (Found: C, 38.98; H, 2.29; N, 6.29; Calc. for C,4H,0N,0,Pb; C, 39.17; H, 2.348; N, 6.52; IR vJNC02180 cm-‘). The filtrate was concentrated to dryness under vacuum and then treated with n-hexanelbenzene mixture (1 : 1, 10 cm3) to afford insoluble tetraphenyl lead, m.p. 227-238OC (lit.,” .m.p. 228OC). The filtrate on concentration and cooling gave tris(pentafluorophenyl)antimony, m.p. 74OC (lit.,4 m.p. 74OC).

Similarly, reaction of tris(pentafluorophenyl)- antimony dichloride (0.694 g, 1 mmol) and hexaphenyl dilead (0.876 g, 1 mmol) afforded diphenyllead dichloride m.p. 285OC (lit.,” m.p. 284-286OC), tetraphenyllead m.p. 226-227OC (lit.,” m.p. 228OC) and tris(pentafluorophenyl)antimony, m.p. 73OC (lit.4 m.p. 74°C).

(iv) Action of (CsFs),SbC12 on bis(triorganotin)- sulphides

Reaction of (C,F,),SbCl, with (Bu,Sn),S. To a well stirred ice cold solution of tris(pentafluorophenyl)antimony dichloride (0.614 g, 1 mmol) in chloroform (50 cm’) bis(tributyltin)sulphide (0.616 g; 1 mmol) in the same solvent (40 cm’) was added drop-wise during half an hour. The reactants were further stirred for 3 hr and simultaneously allowed to attain room temperature. The solution was concentrated to dryness and the residue was dissolved in hot petroleum-ether (bp 60-8OOC). The solution was cooled and filtered, the solid was identified as tris(pentafluorophenyl)antimony sulphide m.p. 122°C. The filtrate was concentrated at reduced pressure to yield tributyltin chloride, characterised as tributyltin fluoride m.p. 242OC (lit.,” m.p. 244OC).

Under similar conditions tris(pentafluorophenyl)antimony dichloride (0.694 g; 1 mmol) afforded tris(pentafluorophenyl)antimony sulphide m.p. 122OC and triphenyltin chloride m.p. (lit.,” m.p. 105-107°C).

1 OS%,

RESULTS AND DISCUSSION

(i) Oxidative addition reactions Freshly generated solutions of tbiocyanogen

(SCN), and iodine-azide and -isocyanate in ace- to&rile were found to react separately with tris(pentafluorophenyl)antimony at - 10°C to give high yields of respective oxidative addition product in which antimony is in the pentavalent state.


Reaction with (SCIQ was performed in the dark to retard its polymerization.

(C,F,),Sb + (SCN),+(C,Fd,Sb(NCS), (1)

(C6FS)sSb + IX+(C6F,),SbIX (2)

(X = N3, NCO).

Whereas reactions of (SC%), have earlier been demonstrated to cleave metal-carbon bonds (M = Sn, Pb)9 those of IN3 and INCO are being reported for the first time with an organometallic compound. However, reactions involving regio and stereo- specific additions of IN3 and INCO to olefins and other systems in synthetic organic chemistry are well known.‘2*‘3

Parallel reactions of interhalogens, viz. ICI and IBr with (C6F5)3Sb under identical conditions as described above were found to produce mixed halo derivatives (I & II Table 1).

(C,F,),Sb + IX+(C6F&SbIX, (3)

X = Cl, Br.

It may be added that ICI, IBr and (SCN), behave as electrophilic reagents towards symmetrical tet- raorganometallic derivatives of group IVB(M = Ge, Sn, Pb)9J’ and cleave the metal- carbon bond(s) to different extents depending upon the relative strength of electrophile used. However, no traces of any pentafluorophenyl-thiocyanate or -halide or of corresponding bis(pentafluorophenyl) derivative, (C6F,),SbX(X = NCS, N3, NCO, Cl, Br), the products normally expected from the possibility of metal-carbon bond cleavage were observed in the above described reactions.

Elemental sulphur was also found to add ox- idatively to (C6F,),Sb in refluxing benzene or ace- tone solution in a dry nitrogen atmosphere to give tris(pentafluorophenyl)antimony sulphide (VI). Similar observations have been made .for triarylantimony (III) compounds:’

(ChF,),Sb + S+(C6F&SbS (4)

(C6F5)3SbS can also be obtained by passing H2S gas in alcoholic-ammonia solution of (C6F,),SbCl,. The molecular weight of sulphide derivative determined cryoscopically in benzene indicates that it exists as a monomer. It may be mentioned that tris(perfluoroalkyl)antimony has been reported not to react with sulphur.ls

(ii) Metathetical reactions (C,F,),SbCl, is an important source for obtain-

ing various. disubstituted tris(pentafluorophenyl)- antimony(V) derivatives (V, VIII-XII, Table 1). Thus the treatment with the corresponding sodium or silver salts in benzene under mild conditions leads to the replacement of both the chloride atoms. The metallic chlorides separate immediately in each case after mixing the reactants.

(C,F,),SbC12 + 2MY-+(C6F5),SbY2 + 2MCl (5)

M = Ag; Y = NCO, NCS

M = Na; Y = ONCMe2; ONCMePh, gCO(CH,),cO, and 00CC6H.,N02 - p.

In sharp contrast, (C,F,),AsCI, has been reported to give monosubstituted products.“j This difference in behaviour can be attributed to the greater tendency of antimony to expand its coordination sphere, and to the lower element-chlorine bond energy.

Formation of oxo-bridge compound (VII). Re- action of aqueous NaN, with (C6F5)3SbC12 in ether solution, however, yielded binuclear oxo- bridge compound (VIII, Table 1) instead of

(C6F,),SbC12 + 2NaN3+

[(C,F,),Sb-o-Sb(C,F,)&%)~ + 2NaCl. (6)

Formation of such a binuclear derivative is not surprising since Gael et al. have reported that R,Sb(N,),(R = Me, Ph) could only be prepared and isolated in the presence of hydrazoic acid in benzene. One of the most usually employed methods for the preparation of organometallic azides involving a water/ether system as described above resulted in the formation of oxo-bridge compound

~Wb--O-=W W3)z.‘7 Selective replacement reactions. Equimolar re-

actions involving mixed halogen compounds ‘(C,F,),SbIX(X = Cl, Br) and metallic salts in benzene produced mixed iodo-pseudohalo derivatives, through selective replacement of chloride or bromide group by a pseudohalo group. The iodide invariably remains bonded to the antimony irre- spective of the nature of the metallic salt used.

256 PREM RAJ et al.

(C,F,),SbICl + NaN,+(C,F,),SbI(N,) + NaCl Ar,Pb + XSn(C,F,),-(C,F,),Sb + Ar2PbX2 (11)

(7)

(C,F,),SbIBr + MNCO-(C,F&SbI(NCO) + MBr

(8)

(M = K, Ag).

This behaviour of tris(pentafluorophenyl)antimony mixed halides is somewhat different from those observed for similar reactions of mixed halides of diaryl-lead(IV) and -tin(IV), where both the different halo groups are replaced by the anionic groups.‘8*‘9 It may be added that in case of group IVB metals identically placed iodide is more readily replaced by silver salts and the chloride and bromide are replaced by the anions attached to the alkali metals.” Selective replacement of halo groups (Cl, Br) have earlier been reported in case of mixed tetrahalocyclopentane tellurates(IV).20

(b) Reaction of (C6F5)$bS with Ar,Pb,. It has been reported by Okawara et al. that the Sb-S bond in triorganoantimony sulphides is semipolar in nature, which facilitates the resonance hybrid of sulphides in the ground state due to which triorganoantimony(V) sulphides are more reac- tive.23,24

R,Sb+-S- = R,Sb = S.

It is therefore not surprising that on reaction of (C,F,)sSbS with hexaaryldileads insertion of sulphur into Pb-Pb bond takes place.

(C6F,)3SbS + Ar,Pb-PbAr3-+

The products (III and IV obtained through exclu- sive replacement of halo group are similar to those obtained by the oxidative addition method (eqn 2) mentioned above and had similar m.p. and superim- posable IR spectra.

Ar,Pb-S-PbAr, + (C6F5)3Sb (12)

The reaction seems to proceed through initial

(III) Reductive cleavage reactions (a) Reaction of(C6F5)$bXz(X = NCO, Cl) with

Ar,Pb*. Exploratory work reveals that higher va- lent metallic halides, viz. Cu(II),, Hg(I1) and Fe(II1) cleave the Pb-Pb bond in hexaorganodilead compounds while themselves getting reduced to the lower oxidation state.*‘” It was therefore, consid- ered worthwhile to study the reactions of tris(pentafluorophenyl)antimony dichloride and diisocyanate against Pb-Pb bond. The former are readily reduced to (C,F,),Sb in the sense of equa- tion shown below

rupture of Pb-Pb bond followed by the insertion of sulphur which may be attributed to the en- hanced semipolar nature of Sb-S bond in tris(pentafluorophenyl)antimony sulphides, which facilitates the homolytic fission of Pb-Pb bond coupled with the remarkable reactivity of Pb-Pb bond.25 In the process tris(pentafluorophenyl)anti- many(V) is reduced to tris(pentafluorophenyl)antimony (III). Similar results have been observed for the reactions of triorganoantimony sulphides with hexaarylditins.

Ar,Pb, + (CsF,)$bX2+Ar.,Pb

+ Ar,PbX, + (C6F5)$b

Ar = Phenyl,p-tolyl

X = Cl, NCO.

(9)

It can be thus concluded that the reactions of hexaaryldileads with tris(pentafluorophenyl)anti- many(V) derivatives proceed via two different path- ways depending upon the nature of the anion attached to antimony atom. In the case of sulphide derivative (eqn 12) cleavage of the Pb-Pb bond is favoured while in the other cases (X = NCO, Cl dissociation of hexaaryldileads to Ar,Pb and Ar,Pb occurred (eqn 9). Both these reactions thus lend support to an earlier held view that the reactions of hexaorganodileads with different reagents differed mechanistically.25

The reaction appears to involve the cleavage of Pb-Pb bond and Pb-C bond in hexaaryldilead yielding stable Ar,Pb and unstable Ar, Pb (eqn 10) which further reduces the perfluorophenyl antimony(V) to perfluorophenyl antimony(II1) (eqn 11).

(iv) Action of (CsF5)3SbC12 on bis(triorgunotin)- sulphide

Bis(triorganotin)sulphides were found to react with tris(pentafluorophenyl)antimony dichloride in 1 : 1 molar ratio resulting in the complete exchange of anionic groups.

Ar,Pb-PbAr, = Ar,Pb + Ar,Pb (10)

(R,Sn),S + (C6F5)3SbC12+

2R,SnCl+ (CeF,)3SbS. (13)


The separation of the products does not pose much difficulty due t? the difference of the solu- bilities in organic solvents. The reaction seems to proceed via a four- &ntred cyclic tratyition state involving sulhpur atom as represented below

R;T;R

(R,Sn),S + R’,SbCl,+Cl - Sp $1 I

I R,Sn - $ SnR,

+

R$;R

[Cl - Sb - S - SnR,] + R,SnCl 1

R;SbS + R,SnCl

(14)

and G(NCX). Thd observed frequencies for these modes of vibrations are listed in Table 2, and are fully consistent with a N-bonded NCX group, in consonance with the usual iso-structure of the hydrocarbon counter parts of the antimony(V).29 The vibrations associated with the NJ stretchings and bending modes (III and VII, Table 2) suggest the presence of a covalently bonded linear N = N = N group. The asymmetric N = N = N stretching is fairly shifted to higher frequency as compared to PhjSb(N&2’7.28 or Ph,SnI(N&30 but other modes of vibrations are not significantly changed. Compound (VII), however, exhibits an additional strong band at 705 cm-‘, which can be safely assigned to the u(Sb4LSb)29*6 vibration, indicating the formation of an oxo-bridge biniclear derivative.

(where R’ - C,F,; R = C4H9, C,H,).

An analogous mechanism has been proposed for the reaction of Cph,Sn],O and HgC12.M

Tris(pentafluorophenyl)antimony disuccinimide (IX) displays a strong’ band at 1700 cm-’ assignable to “ester-like” CO group. The symmetric stretching mode appears at 1235 cm - ’ . Pattern and position of the bands are comparable with those of reported triarylantimony diamides.7

The molar conductance values of 10 - 3 M solu- ticon in acetor&fi>e o!i tie newjy syn%nti&b tris(pentafluorophenyl)antimony(V) compounds range between 13-35 mol-’ cm*, which indicate their non-conducting nature.27 The values for compounds (I-IV) containing a halide atom are almost of the same order and higher than the rest of the ccmpaunds but do naC suggest canducting be&av- iour.

The observed molecular weight data of the com- pom& jn Ereezjng benzene were found compmabJe with those of theoretical values which suggests that these compounds exist as monomers.

The newly isolated compounds are stable at rcoDm rempera’rure anb scinjie ‘In ogatilc s&ven@. viz, chloroform, acefonitrjfe, benzene etc. Com- pounds (II), (IV) and (VIII), however decompose on storage. Isocyanate derivatives were also found tcobe m&me S&-i&t.

The separation (375 cm-‘) between the asymmetric and symmetric (0 = C = 0) stretching frequencies for tris(pentafluorophenyl)antimony di(p-nitrobenzoate), which occur at 1685 cm-’ and 1310 cm-‘, respectively, in the solid state suggest the presence of a monodentate “ester-like” carboxylate group with a penta-coordinate structure about the antimony atom. In chloroform solution the 1685 cm-’ band is shifted to 1682 cm-’ but the symmetric (0 = C-O) stretching frequency remains unchanged and thus carboxylate group retains its unidentate character in solution as we1LW3’ The non-conducting and monomeric nature and the absence of carboxylate ion in the IR spectra further rules out the possibility af au ionic structure.

IR SPECTROSCOPY

All the isolated compounds (I-XII; Table 1) exhibit IR absorptions characteristic of CQF, group and are in conformity with those reported earlier fcr Iris(~nraAuaraqhn~~~andmany and its &id- ides.s,28 The IR frequencies due to fundamental modes of vibrations of the anionic groups are listed im”l &le^L.

Tse Ia sp&sa ofetsjs~~~taA~~~~~~~~~~~~~$j- mony dioximates (XI and XII) do not exhibit any band in the region 3000-3380 cm-‘, assignable to the inttamalecularly hydrogen bonded OH in free oximes.A*The C = N vibrations cu. 1630 * 5 cm-’ appear as medium bands and are lowered by cu. 40 cm-’ as compared to the free oximes (- 1668 cm-‘). The lowering of the VC = N vibration may be attributed to the stabilization of the C = N bond by resonance with the non-bonding electron pair on axygen aCam aft&e amina graaq. Hawever, this type of lowering may also be related to the mass effect as has been observed earlier, in case of group IVB Clernears?

Absorptions associated with the various modes The appearance of a medium band in the region of vibrations of the pseudohalide groups have been 915-925 cm-’ can be attributed to a N-O stretch- identified and indicate the nature of bonding to the ing vibration” while the Sb-0 stretching is ten- atntimony atom. ne chalcogenate grouup, &&&y as&gn& a1 480-t 5 cm- I on ?ne ‘oasis 02 NCX(X = S or 0) gives rise to three fundamental reported S&O frequencies in the corresponding modes of vibrations due to the Y(C =N), v(C - X) organoantimony oxinate derivatives.3’

258 PREM RAJ et al.

A noticeable feature of the IR spectra of all the 11. S. N. Bhattacharya, F&n Raj and R. C. Srivsstava, isolated disubstituted compounds is the absence of J. Organometal. Chem. 1976, 105, 45.

the v,,, @b-C) absorption corresponding to the 12. L. F. Fieser and M. Fieser, Reagents for Organic

r-mode which should be located in the region Synthesis, p. 500. Wiley, New York, (1968).

250-3OOcm-’ as reported by earlier workers.s*6 13. S. N. Moorthy and D. Devaprabhakara, Chem. Znd.

Thus on the basis of IR evidences coupled with 1975,217.

their monomeric and non-conducting nature and 14 R. W. Leerier, L. Summers and H. Gilman, Chem.

in accordance with the structures of other or- 15 . ganoantimony(V) compounds,6*7*17*29 the newly syn-

thesised disubstituted derivatives (except for (VII)) can reasonably be assigned a trigonal bipyramidal structure with the anionic groups at the axial positions and C,F, groups occupying the equa- 16. torial positions. A trigonal bipyramidal structure containing an oxygen bridge (Sb-0-Sb) can be 17* proposed for compound (VII). 18.

Rev. 1954;54, 101.

Acknowledgement-The authors are thankful to the 19 Head of the Chemistry Department, Lucknow Univer- sity for providing the necessary Laboratory Facilities, the Director RSIC, Lucknow for obtaining IR spectra and Council of Scientific and Industrial Research, New

2. .

Delhi for financial assistance (KS & AR). 21.

1.

2.

3.

8.

9.

10.

IWFEXWNCE!S

G. 0. Doak and L. D. Freedman, Organometallic Compounds of Arsenic, Antimony and Bismuth. Wiley-interscience, New York, (1970). A. T. Rake and J. M. Miller, J. Chem. Sot. A 1970, 1881. J. P. Crow and W. R. Cullen, Organic compounds of arsenic antimony and bismuth. In Inorganic Chemistry, Series One, M.T.P. International Review of Science (Edited by H. J. Emeleus and B. J. Aylett) Vol. 4, p. 383. Butterworths, London (1972). M. Fild, 0. Glemser and G. Christoph, Angew. Chem. 1964,76,953. B. A. Nevett and A. Perry, Spectrochim. Acta 1975, A31, 101. A. Otero and P. Royo, J. Organometal. Chem. 1978, 154, 13. Prem Raj, Ashok Ranjan and A. K. Saxena, Znd. J. Chem. 1983, 22A, 120; Press Raj; Ashok Ranjan, Kiran Singhal and Rajiv Rastogi, Synth. React. Inorg. Metal-Org. Chem. 1984,14(2), 269. R. D. Chambers and T. Chivers, Organometal Chem. Rev. 1966, 1, 279. S. N. Bhattacharya, Prem Raj and R. C. Srivastava, J. Organometal. Chem, 1975, %7, 279. R. C. Poller, The Chemistry of Organotin Com- pounds, p. 13 1. Logos Press, London (1970).

22.

23.

24.

25.

26.

27. 28.

29. 30.

31.

32.

33.

34.

35.

R. E. Banks and R. N. Haszeldine, Polyfluoroalkyl derivatives of metalloids and non-metals. In Ad- vances in Inorganic Chemistry and Radiochemistry (Edited by H. J. Emeleus and A. G. Sharp@, Vol. 3, p. 367. Academic Press, New York (1961) A. Otero and P. Royo, J. Organometal. Chem. 1978, 149, 315. R. G. Goel and D. R. Ridley, Znorg. Chem. 1974,13, 1253. S. N. Bhattacharya and Prem Raj, J. Inorg. Nucl. Chem. 1978,40,1699; Prem Raj, Zmf. J. Chem. 1979, 178, 616. S. N. Bhattacharya and Prem Raj, Znt. Conf on Coordination Chemistry of Ge, Sn. Pb. Nottingham, England (1977). T. N. Srivastava, R. C. Srivastava and Mala Singh, J. Organometal Chem. 1978, 157, 405. D. P. Arnold and P. R. Wells, J. Organometal. Chem. 1976,113,311. D. P. Arnold and P. R. Wells. J. Organometal Chem. 1975, 111, 1285. M. Shindo, Y. Matsumura and R. Okawara, J. Organometal. Chem. 1968, 11, 299. J. Otera and R. Okawara; J. Organometal. Chem. 1969, 16, 335. H. Shapiro and F. W. Frey, The Organic compounds of Lead, p. 166. Wiley, N.Y. (1968). D. Datta, B. Majee and A. K. Ghosh, J. Or- ganometal Chem. 1971, 29, 251. W. J. Geary; Coord. Chem. Reu. 1971,7, 81. D. A. Long and D. Steele, S’ctrochim. Acta 1963, 19, 1955; I. J. Hyams, E. P. Lippincott and R. T. Bailey, Spectrochim. Acta 1966, 22, 695. E. Maslowsky, J. Organometal. Chem. 1974,70, 153. Prem Raj, Ashok Ranjan, Kiran Singhal and A. K. Saxena, Acta. Chem. SC&, submitted. H. Schmidbaur and H. Stiiehler, Angew Chem. Znt. Ed. 1972, 11, 145. R. E. Rundle and M. Parsole, J. Chem. Phys. 1952, 20, 1487. P. G. Harrison and J. J. Zuckernunn, Znorg. Chem. 1970, 9, 175. S. Califanio and W. Luttke. 2. Phys. Chem. 1956,6, 83; J. Fabian, M. Legrand and P. Poirlier, Bull. Sot. Chim. Fr. 1956,1499. H. A. Meinema and J. G. Noltes, J. Organometal. Chem. 1969,16,257.

synthesis and some reactions of tris (pentafluorophenyl) antimony compounds

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