Infrared spectra of triphenyltin compounds in the 650-200 cm−1 region

Speeuoehimiea Acta,Vol. 27A,pp.598to 597. Pewuson Press 1971.

Printed UINorthern Ireland

Inbared spectra of triphenyltin compounds in the MO-200 cm-l region T. N. SRIVASTAVA end S. K. TANDON* Department of Chemistry, University of Lucknow, Lucknow, India (Received23 January 1970; rev&& 17 September 1970) Ab&&-Some triphenyltin derivatives hsve been exsmmed in the region 660-200 cm-1 and absorption associated with phemylring vibrations, tm-phenyl, tin-pseudohslogen, tm-oxygen and tm-sulphur stretohmgs have been assigned.

hFRODUCTION

studies of organotin compounds in the “KBr-CsBr” region have gained considerable importance in recent years because many absorptiona due to bonds between tin snd other groups appesr in this area. Thus KRlE(tSMBNN et al. [l-3] studied complete i.r. and Raman spectra, of organotin hydroxides, oxides snd halides. while OEAWARA et al. [4, 51 made the measurements down to 300 cm-l for trialkyltin formates and hydroxides. HARRAHet al. [6]discussed the spectra of a number of phenyltin compounds and extended the measurements to 190 cm-l in some cases. POLLER [7] has made a detailed spectral study of phenyltin halides, Ph,SnXo_,, (X = Cl or I, 12= l-3),triphenyltin bromide and triphenyltin fluoride. He placed Y, (Sn-Ph) at 270-280 cm-l and y,(Sn-Ph) at 230-240 cm-r; these assignments were previously uncertain [I, 3-101. Recently, SMITH[l l] examined the spectra, of a few phenyltin compounds in the cesium bromide region and made assignments for the five low frequency phenyl ring modes of vibration and many absorptions associated with the deformation of tetrahedral skeleton. During the course of our studies on organometallic compounds of group IV elements, we synthesized various triphenyltin derivatives and the infrared spectra of the compounds represented by the formula R,SnX(X = NCS, NCO, COOCH,, COOCsH, and ONO,) and (R,Sn),X (X = S, SO,, SeO, and SeO,) were examined in the region 659200 cm-l.

INFRARED

* Present address: Depsrtment of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221. [l] H. KRIEQSXANNand H. GEIS~LXR,2. Anwg. AZ&em.Chem. 838,170 (1963). [2] H. Kmuosw, H. HOEFNANNctnd S. PIS~HTBCEAN, 2. Anorg. AZZgem.Chem. (1962). [3] H. KRIEQ~ and S. PISCETSCEAN, 2. Awn-g. AZZgem.C&m. SOS,212 (1961). [4] R. Ogawaa~ and M. OEABA, J. Oqanometd. C?~rn. 1,360 (1964). [6] R. OKAWARA and K. YASUDA, J. Organometd. C&m. 1,356(1964). [S] L. A. HARRAH,M. T. RYAN snd C. T~oasxr, S~eetmchi~. Acta 18,21(1962). [7] R. C. PO-, Spectrochim.Acta a& 936 (1966). ES snd G. A. W. DERWISH,J. MOE.Spectry 2, 148 (1960). [S] V. S. GRIYFI!C N and M. SCIEMIDT,J. Organometal.Chem. 8,486 (1966). [9] H. SOHUMAN [lo] T. S. SRIVASTAVA,J. OrgawmetaL Chem. 10,373(1967). [11] A. L. SMITE,S~~ectrochim. Acta 24A, 696 (1968). 693

815, 283

T. N. SRIVAEITAVA and S. K. TANDON

594

EXPERWENTAL

The preparation and purification of the compounds have been reported earlier [12,131. The spectra were run on a Perkin-Elmer 225 Grating spectrophotometer

as Nujol mulls using both cesium bromide and polyethylene discs as supports. Cesium bromide was used in the 650-400 cm-i region whereas polyethylene gives better results in the 400-200 cm-l region. The main absorption bands along with their probable assignments are given in Table 1. Spectrograms of two typical Table1. Infrmedspectre m the 660-200cm-l region and assignments for triphenyltin compounds

A5lqnment 6b(B,)

1* 616 VW

cYNC0 P Sn-0 wbratmn

2

3

618 VW 610~

616 VW

4

6

614 VW

616 VW

664 w(b)

670 w(b)

6 617~~

7 616~~

8

9

618~1~

614~1~

606 w(b) 515m

;NCS 16W,)

466 w ( 460 V8 442 ah

do-se-o vSn--NC0 Yag Sn-S-Sn y, Sn-s-sn vSn--NCS 326 w 80-se--o *“(Ad (~Sn-C,H, Sn--C,H,269 8 228 m

446 s

463 8

448 8 438 m

460 8

464 8 444 B

446 *

466 s 446 s 396sh

448 B 439 ah 39Osb

326 w 273 8 226 m

300 w 272s 226 m

380 w(b) 377 w(b) 331 m(b)

270 s 227 m

270 8 228 m

268 8 228 m

268 m 227 w

267 8 228 m

270 m 22.5 w

l Cornpam&: 1 = (C,H,),SnNCS, 2 = (C,H,),SnNCO, 3 = (C,H,),SnOCOCH,, 4 = (C,H&3nOCOC,H,, 5 = (C,H,),SnONO,, 6 =[(C~H&,Sn],S, 7 =[(C,H,),Snl,s0, 8 = [(C,H&Snl&3eOll,9 =[(CdHI)&$seO,.

compounds namely triphenyltin isothiocyanztte and bis-triphenyltin sulphide are shown in Fig. 1. RESULTS AND DISCUSSION Phenyl ring vibrations

Assuming local symmetry of phenyl ring as C,, and using WILSON’S notation [14],we denote the observed three infrared active ring vibrations [15]in the region 650-200 cm-l as X-insensitive 6b(B,)and the X-sensitive 6a(A,)and 16b(B,)modes. A weak band observed within the narrow range 614-618 cm-l is assigned to the 6b(B,) mode in the triphenyltin compounds. The absorption of strongest intensity occurs at 446 f 8 cm-l and has been assigned to the 16b(B,) ring vibration in agreement with previously reported spectra of phenyltin compounds [6,71. In most of the cases, the band appears as a doublet which may arise from coupling of 16b vibrations due to the presence of more than one phenyl group in these compounds [ 151. This band was erroneously assigned as Y,(Sn-Ph) by a few earlier workers [l,9, lo]. POLLER [7]however, questioned this and advanced strong arguments in favour of the assignment suggested above. [12]T. N. SRIVASTAVA and S. K. TANDON, In&an J. Appl. Chem. 26, 171 (1963). [13] T. N. SRIVASTAVA and S. K. TANDON, J. Prakt. Chena. 311,878 (1989). [14]E.B. WILSON, Phys. Rev. 45, 706 (1934). [IS]W. R.MOWHINNIE and R. C.POLLER,Spectrochm. Aetu 22, 501 (1966).

Infrared spectra of triphenyltin compounds m the 660-200cm-l region Wavelength,

I

I

J 50

1 600

,u 25

20

40

30

I

I

I

400

500

596

I

!

I 300

i

cm-l

Fig. 1. Infraredspectra of tnphenyltm Isothiooyanate (above) and bis-triphenyltm sulphide (below).

Later SRI~ASTAVA [16] revised his earlier assignment [lo] to this absorption and attributed it to a phenyl ring vibration as suggested by POLLEE[7]. The 6&4,) mode has been ascribed to a phenyl ring vibration that is sensitive to the nature of the substituent on the ring. In our compounds, the substituent in every case is Sn atom and the vibration is essentially a phenyl-tin vibration. This has been discussed next. Tin-ph.enyl

stretching viindion

All of our compounds show an intense absorption at ~270 cm-l and a band of medium intensity at ~227 cm-l which are attributed to v,,(Sn-Ph) and Y,(Sn-Ph) respectively [7]. The literature [7, 161shows that r,(Sn-Ph) almost invariably falls at 265-275 cm-l, but there is no agreement on the corresponding symmetric mode, which has been reported at 240 cm-l [7], 210 cm-l [l] and 230 cm-l [lo]. Since the 225-228 cm-l band is consistently observed in all of our compounds, our assignment of this to v,(Sn-Ph) mode seems reasonable. [lS]

T. S. SSI~ASTAVA, J. OqpmrnetaZ. Ohm. 16 (2), P53 (1969).

T. N. SRIVASTAVAand 8. K. TANDON

696

Paeudohalogen and ti~aeud&alogen

vibrations

Organic isothiocyanates and isocyanates [17]show out-of-plane bending vibrations due to -NCS and -NC0 groups in the range 450-460cm-l and -609 cm-r, respectively. The weak but sharp bands at 465 and 610 cm-l in the spectra of triphenyltin isothiocyanate and isocyanate can be assigned to this mode. TEAYER and STROMMEN [18] observed these bending vibrations at 478 and 618 cm-l in the corresponding trimethyltin compounds. In addition to the pseudohalide deformation vibration, tin-pseudohalide stretching and deformation modes would also be expected in this region [19].The weak broad band at 380 cm-” in triphenyltin isocyanate may be assigned to the Sn-NC0 stretching vibration, in good agreement with the value of 400 cm-1 reported for Me,SnNCO [IS].An absorption at 326 cm-l in the corresponding isothiocyanate is tenatively assigned to the Sn-NCS stretching mode, which would be expected at lower frequency than Sn-NC0 stretching [18]or Ge-NCS stretching which has been placed at 368-370 cm-l in triarylgermanium isothiocyanates [20]. These results indicate a direct Sn-N linkage and therefore support our proposed iso structure for the two organotin pseudohalides [21].This has been confirmed by X-ray crystal study of trimethyltin isothiocyanate [22]. The metal-pseudohalogen deformation bands lie at still lower frequency and are liable to be missed due to their weak intensity [19]. Tin-aulphur

stretching vibrations

The spectrum of bis-triphenyltin sulphide shows two broad bands, one of very strong intensity at 377 cm-l and other of medium intensity at 331 cm-l, which are assigned to the asymmetric and symmetric Sn-S-Sri stretching vibrations respectively. The values exactly match those reported by SCHUMA~ and S~HBDT for the same compound [9]. T&oxygen

vibration

A band observed at 567 6 3 cm-l in the spectra of triphenyltin benzoate and nitrate may be due to a Sn-0 vibration ; this would be in good agreement with the values of 548-578 cm-l [23] and 536-575 cm-l [24] reported for this vibration. POLLER [25] obtained an approximate

value of 570 cm-l for y(Sn-0)

the force constant using GORDY’S rule [ZS].

by calculating

This falls near the range of 580-643 cm-l

[27] for some oxygen containing methyltin compounds and is in agreement with his own values for phenyltin derivatives [25]. In triphenyltin

found by ROCHOW et al.

[17] [18] [19] [ZO] [21] [22] [23] [24] [26] [26] [27]

N. S. Haaa and J. B. WILLIS, Spectmhim. Acta 16,279 (1960). J. S. TEAYER and D. P. STRO~N, J. OrgmwmetaZ. Chem. 6i, 383 (1966). J. S. T~YER and R. WEST, A&. Orga?wmekzl.C&m. 5, 169 (1967). T. N. SRIVA~TAVAand S. K. TANDON, J. Iwg. Nd. Chem. 80,1403 (1968). S. K. TANDON, Ph.D. Thesis, Lucknow University, Lucknow, India (1966). J. B. HALL, 1?aMg. CRAWL, 111 press. J. S. MORRISONaud H. M. HAEKDLER,J. Imwg. NW.% Chem. aS, 393 (1967). R. C. AUUARWALand P. P. SINUH,J. Inwg. Nwd. Chem. $B, 1661 (1966). R. C. POLLER,J. Inorg. Nucl. Cherra. f%%,593 (1962). W. GORDY,J. Chews. Phya. 14,305 (1946). M. P. BROWN, R. O~AWARA and E. G. ROCHOW,SpectrochGn. Acta 16,695(1960).

Infrared spectra of triphenyltm compounds in the 660-200 cm-1 region

697

acetate, a weak broad band at 606 cm-l may arise from the interaction of Sn-0 and -COO out-of-plane bending vibrations [28]. Other v&ations

The spectra of bis-triphenyltin selenite and selenate each show two absorptions at 396-395 cm-l and 300-325 cm-l, which could be due to O-Se-O bending modes. MARURAVE et al. [29] have assigned the higher frequency band as O-Se-O asymmetric bending and the lower one as its symmetric bending mode in the spectra of a number of inorganic selenites and selenates. A medium band observed at 515 cm-l in the spectrum of bis-triphenyltin selenite may possibly be due to a Sn-O-Se vibration [29]. However, the corresponding band in case of bis-triphenyltin selenate could not be located. We aregratefulto Dr. R. K. KHANNAfor recording the spectra of compounds rtt the Umverslty of Maryland, College Park, Maryland and to Dr. J. 8. TEAYER of the University of Cmcmn&, Cm&m&l, Ohio for helpful discuswons and cntxxsms.

Achowledgtmmts--

[ZS] K. E. LAWSON, Infrcmd Abaorptim of Inorganic Subatancm. Remhold (1961). [29] K. SAT-A-DAX, L. D. MCCORY and J. L. MABWA~E, S~ectrocGn. Acta 20,967

(1964).