o -'vi• I

00(1)

iodide to iodine, ferrous to ferric, arsenite to arsenateand sulphide to sulphur' in acid medium.

The magnetic susceptibility of the compoundmeasured on a Gouy balance is -349.6 X 10-6 B. M.at 302K, indicating the compound to be diamagnetic.ESR spectrum (X-band with 100 Hz field modula-tion) of the brown coloured alkaline solution (seemethod of preparation), did not exhibit any bandconfirming the diamagnetic nature of the solutioncontaining Ni(I04):- ion. The IR spectrum of thecompound recorded on a Perkin-Elmer models 577instrument in CSI phase exhibited a strong andbroad band in the region 3500-3360 em"! assignableto hydrogen, bonded (OH 0) vOH. Thecorresponding aOH appeared at 1650 crrr-'. Inaddition peaks at ]470-1420, 710 and 600 cm-1have been assigned to ar·OH, '11-01 and vI-O(H)respectively. The aO-I-O appeared as multiplepeaks in the range 450-250 cnr-'. vNi-O could notbe detected. Too many bands in the lower rangemay be due to distortion in the octohedral geometryround iodine atomv".

The electronic spectrum of the brown colouredmother liquor in KOH recorded on a Varian Tech-tron instrument, exhibited a shoulder with highextinction (IE = 27,500) at 410 nm. The band inthe visible region could be assigned to the transitioninvolving charge transfer from metal tu orbital toligand orbital. The band at 210 nm was assignable'?to 10~ - species. Electronic spectrum thus esti-blishes octahedral geometry'! both round nickel andiodine atoms. The intense colour of the compoundmay be due to some type of covalency and may alsoarise from distortion in the octahedral geometry.

The compound gradually decomposed at 750°Cto give Li20, NiO, 12, H20.

Li2NiI6024, 6H20 may be considered to havestructure similar to that of TeMo60g~ ion12 (seestructure I). It has the Anderson. Evans modeland is a 1:6 hcteropoly acid. The nickel ion occu-pies the central octahedron and is surrounded bythe six lOGoctahedra. There will be some distortionfrom the idealised octahedral geometry due todifferent Ni-O and 1-0 bond lengths. ICVI!) possessall the criterion to function as an addendum inheteropoly complexes because of its small size, high

NOTES

positive charge and ability to take tetrahedral andoctahedral geometry with oxygen. This compoundbelongs to a new category of heteropoly species.A complete structure determination by Xvray crystal-lographic measurement will be communicated latter.

The authors thank Dr N. R. Sengupta, GSI,Calcutta. for atomic absorption measurements oflithium, Dr A. Roy, Saha Institute of Nuclear physics,Calcutta for the ESR spectrum and Dr B. K. Sen,Department of Pure Chemistry, Calcutta University,Calcutta, for active help and valuable suggestions.

References1. MALAPRADE, L., C. r. hebd. acado seanc. Paris., 204

(I 937) , 979; 210 (1940), 504; 238 (1954). 2:}22; BullSoc. chim. Fr., 5 (1938), 582; 7 (1940), 43; 6 (193'),223; 9 (19J,2), 832.

2. RAY, P. & SARMA, B .• J. Indian chem. Soc., 25 (1948),205; Nature 157 (1946), 627.

3. VANNERBERG, N. & BWCKHAMMER, I., Acta chem. scand.,19 (1965), 875.

4. NYMAN, C. J. & PLANE, R. A., J. Am. chem. Soc., 83(1960),2617; BAKER, L. C. W., LEBIODA, L., GRO·CHOWSKI, J.. MUKHERJEE, H. G., J. Am. chem. Soc.,102 (1980), 3274.

5. CAMBELL, M. J. M. & NYMAN, C. J., Inorg, chem., 1(1962), 842.

6. WILLARD, H. H. & FURMAN, N. H., Elementary quanti-tative analysis (D. Van Nostrand, New York), 1940,szo.

7. SIEBEitT, H., Fortschr. Chf!rn. Forsch., 8 (1967), 470.8. MUKHERJEE. H. G. & CHOUDHURY, B. K., J. Indian chem.

Soc., 56 (1979), 10')8.9. LOKIO, A. H. J. & KYRKI, J. R., Chern. Abstr., 80 (1974),

9904g.10. CROUTHAMEL, C. E. & MARTJN, D. S., J. Am. chem. Soc.,

71 (1949), 3031.11. BAKER L.C.W. & WEAKLEY, T.J.R. J. inorg, nucl. Chem.,

28 (1966), 447; FLYNN (JR.) C. M. & STUCKY, G. D.,Inorg. Chem., 8 (1969), 3:}3.

12. EVANS, H. T. (JR.), J. Am. chem. Soc., 90 (1968), 3275.

Metal Derivatives of Organoantimony Compounds :Reactions of Anhydrous Ferric Chloride with Arylanti-

mony Compounds+

HEMANT K. SHARMA. SORAN SINGH, S. N. DUBEY & D. M. PURl·Department of Chemistry, Kurukshetra University,

Kurukshetra 132 119

Received 1 May 1981; revised and accepted 22 February 1982

Reactions or anhydrous ferric chloride with aryl antimonycompounds have been studied. Tetraphenylstibonium chloridereacts with ferric chloride to give complex salts [Ph.Sb][FeCI.land [(Ph.Sb)(FeCI.)h,Ph.SbCI while triphenylantimony dichlo-ride forms adducts of the type Ph"SbCJ z-2FeCI3• Ferric chloridereacts with trlphenylstlbine to form triphenylstibine dichlorideand in the process it is reduced to bivalent state. The com-plexes have been characterized on the basis of elemental analyses,Mossbauer and IR spectral data, magnetle susceptibility andconductivity measurements.

tThis paper was presented at the Symposium on MadanTrends ill Coordination Chemistry held on 6-8 October, 1980on the occasion of the Diamond Jubilee Celebrations of theInstitute of Science, Bombay.

619

INDIAN J. CHEM., VOL. 21A, JUNE 1982

REACTIONS of chlorides of TI(IInl, Cu(II)2.3and Hg(IW with triarylstibines have been

reported to give the corresponding dichlorides,Reactions of alkyl- and aryl-antimony compoundswith titanium tetrachloride have been studied byTakashi" and Puri et aUi Recently, ionic complexesof tetraphenylstibonium halides with diphenyltellu-rium dichloride" or triaryltin pseudohalides? havealso been reported. However, no attempt seems tohave been made to study the reactions of arylanti-mony compounds with anhydrous ferric chloride.We report here the synthesis and characterizationof some novel complexes of arylantimony com-pounds with anhydrous ferric chloride.

Anhydrous ferric chloride (BOH) was used afterit gave satisfactory analysis. Triphenylstibine (E.Merck) was used after checking its purity. Tetra-phenylstibonium chloride and triphenylantimonydichloride were prepared by the known methodsv'e.Solvents (benzene and n-hexane) were dried anddeoxygenated before use. Because of the hygro-scopic nature of the reactants and products, all thepreparations were carried out under anhydrous con-ditions. To avoid oxidation of the compounds,dry nitrogen gas was flushed into the reactionmixture.

(i) Reactions of anhydrous ferric chloride withtetraphenylstibonium chloride in refluxing benzene inthe molar ratios of I:I and 2:3 - To I M and 2Msolutions of ferric chloride in dry benzene takenseparately, were added slowly and with constantstirring, 1M and 3M solutions respectively of tetra-phenylstibonium chloride under an atmosphere ofdry nitrogen. In both the cases the colour of thereaction mixture turned orange, and a pale-yellowcompound started precipitating. Nitrogen gas waspassed through the solution for about 12 hr. Theflasks were stoppered and kept aside for completeprecipitation. The supernatant liquid was decantedoff and the yellow solids obtained were washedwith dry benzene and n·hexane respectively. Thecompounds were dried in vacuo (1-2 mm) at roomtemperature. The yields were 74 and 61 % respec-tively. Elemental analyses of the compounds aregiven below:Compound I: (Found : CI, 23.83; Fe, 8.64. Re-

quired for (Ph4Sb][FeCI4] : CI, 23.16; .Fe, 8.92 %J.

Compound II : [Found: CI, 18.66; Fe, 6.26. Re-quired for [(Ph4Sb)(FeCI4)h Ph4-SbCI : CI, 18.59; Fe, 6.51 %J.

(ii) Reaction of anhydrous ferric chloride withtriphenylantimony dichloride - A ferric chloride solu-ion (0.364 g, 2M) in dry benzene was mixed drop-wise under an atmosphere of dry nitrogen with abenzene solution of triphenylantimony dichloride(0.492 g, 1M). The bath temperature of 100" wasmaintained during refluxing. After refluxing for 15hr a brown solid started precipitating. The reactionmixture was cooled and kept aside for one day forcomplete precipitation. The supernatant liquid wasthen decanted off and the solid was washed first withdry benzene and then with dry n-hexane. The

620

compound (yield 66 %) was dried in vacuo at roomtemperature [Found: C, 38.64; Fe, 14.84. Requiredfor Ph3SbCI2.2FeCI3 : Cl, 37.95; Fe, 14.92%J.

(iii) Reaction of anhydrous ferric chloride withtriphenyl stibine - To a benzene solution (2mmol)of ferric chloride was added benzene solution (Immol) of triphenylstibine, slowly and with conti-nuous stirring under an atmosphere of dry nitrogen.The nitrogen gas was passed for 24 hr with occa-sional shaking. A light-green residue of ferrouschloride was filtered off and washed 2 to 3 times withdry benzene. It was dried and analysed. Theanalysis of the residue corresponded with ferrouschloride. The filtrate, on evaporation of benzene,yielded a crude product of triphenylantimony dichlo-ride, which was recrystallized from benzene (m.p.142°).

Infrared spectra of the compounds (4000-600 cm-l)were taken in nujol on a Beckman IR-20 spectro-photometer. Far IR spectra of the compounds(600-250 cnr-') were recorded using polythene sheetsand nujol for sample preparation. Mcssbauerspectra were taken on constant velocity can drive.

The conductivities of dilute solutions (l x lo-3M)in nitrobenzene were measured on an Elico-conduc-tivity bridge type CM-82T. The magnetic suscepti-bility measurements were carried out on a Gouybalance.

The analytical data indicate the formation of twodifferent complexes (Ph4Sb] fFeCI,,] (I) and fPh"SbJ3-[FezClMII) in the reaction of tetraphenylstiboniumchloride with ferric chloride in the molar ratio of1: 1 and 3: 2 respectively. The reaction of triphenyl-antimony dichloride with anhydrous ferric chloridein 1 : 2 molar ratio carried out under nitrogen at-mosphere in refluxing benzene at an oil bath tempe-rature of 100° gave a solid product, III, the elemen-tal analyses of which corresponded to the compo-sition 2FeCI2.PhaSbCI2• The addition compound wasfound to be insoluble in common organic solvents.However, when triphenylstibine was reacted withanhydrous ferric chloride in a molar ratio of 1:2under dry nitrogen atmosphere, Fe(III) was reducedto Fe(II) state and triphenylstibine was convertedto the corresponding dichloride. Similar reductionproducts have been reported by earlier workers="also.

The quaternary stibonium salts (I and II) werefound to be ionic as indicated by their molar con-ductance values of 29.2 and 63.7 mhos em" mcl+!respectively in nitrobenzene.

The magnetic moments of the complexes (I andII) were found to be 5.64 and 6.1 B.M. respectivelyat room temperature. This suggested a spin-freetetrahedral geometry for both the complexes",

The infrared spectra of the cation( Ph4Sb]+ in thecomplexes (I and II) showed sharp bands in theregion 430-440 cm-l which could be assigned tovSb-C(Ph) mode. This finding is in agreement witha band observed at 430 cm-1 by Hendriksma" for(Ph4Sb]2 [Re2CIs]. Since only one band is presentdue to vasSb-C vibrations, in both the compounds,it can be concluded that all the four bonds in the

[Ph,Sb]+ cation are equivalent and the cation has atetrahedral geometry (Td symmetry).

Another strong band at 370 cm-1 is observed incompound I; it could be due to Va vibration indica-ting the presence of tetrahedral geometrylO,ll of theanion [FeCI,]-. The occurrence of a band of mediumintensity at 360 cm-1 in the spectrum of the com-pound (II) suggests that a tetrahedral tetrachloro-ferrate ion [FeCI,]-, instead of the dinuclear anion[Fe2Clo]3-, is present in the compound (II). Mag-netic moment data of these compounds also suggestthat in both the compounds the anion is similar.This is further confirmed by Mossbauer spectralstudy of both the compounds.

In the Mossbauer spectra of the compounds, theisomeric shift (8) was observed in the range of0.40-0.42 mm/sec at room temperature with respectto stainless steel which suggested the presence oftetrahedral high-spin iron cornplexes'". In the caseof R[Fe(III)CI,], the isomer shift of 0.4 mm/seccorresponds to 3d14so.40 configuration suggesting a4s electron population of 0.41 (as calculated fromM. O. theoryj-". The quadrupole splitting (.6,Eq)values are 0.6 'and 0.65 mm/sec. Normally thereshould not have been any quadrupole interactionsw,But in compounds having large cations, some qua-drupole interactions are observed due to distortionin cubic symmetry16,J6. In the cases of cationshaving tertiary groups, the splitting is large whilein other cases it is small and therefore the distortionis also small.

Therefore, compound (II) should be representedby the formula L(Ph,Sb){FeCI')]2.Ph,SbCl insteadof lPh4SbMF~CI.] ..

PMR spectra of compounds I and II in DMSO-d.show peaks in the range ~ 7.38-7.90. These peaksare complex multiplets and can be attributed to theprotons of phenyl rings of tetraphenyl stiboniumcations.

In the IR spectrum of the adduct 2FeCI3.PhaSbCI2,the bands due to vSb-C(Ph) and phenyl ring vibra-tions did not shift to lower frequency on the forma-tion of the adduct, whereas a band observed at 280cm-l due to v(SB-Cl) vibrations shifted to lowerfrequency region indicating that the adduct is formedthrough chlorine bridges. The presence of anotherband at 360 cm-1 in the adduct 2FeClaPh3SbCl2could be assigned to (Fe-Cl) terminal vibrations'".

The authors thank Prof. H. K. Pujari, Head ofthe Chemistry Department, Kurukshetra Univer-sity, Kurukshetra for providing necessary laboratoryfacilities. Thanks are also due to the CSIR, NewDelhi for providing financial assistance to one ofthem (H. K. S.).

ReferencesI. GODDARD, A. E., J. chem. s«: 123 (1923), 1161.2. VAUGURA, D., ONDREJOVIC. G., MAKANOVA, D. & GAZU,

J., Chern. Abstr., 82 (1975), 25297h.3. BHATTACHARYA. S. N. & SINGH, M., Indian J. Chem.,

18A (1979), 515.4. TAKASHT, Y., Bull. chem. s«; Japan, 40 (1967), 1194.5. SHARMA, H. K., DUBEY, S. N. & Ptnu, D. M., Indian J.cs«. 20A (1981), 620.

NOTES

6. SRIVASTAVA, T. N., S