Preparation & Characterization of Some Triarylarsenic
Indian Journal of Chemistry Vol. 16A, September 1978, pp. 778-781
Preparation & Characterization of Some Triarylarsenic & Triarylantimony Mixed Halides & Related Compounds
S. No BHATTACHARYA· & (Miss) MEEKU SINGH Department of Chemistry, Lucknow University. Lucknow 226007
Received 3 December 1977; accepted 17 February 1978
Iodine halides (ICI, IBr) and cyanogen halides (ICN, BrCN) have been found to add oxida- tively to triaryl-arsines and -sttbmes under very rntld conditions. Corresponding btsmuth compounds under identical conditions are found to go blsmuth-aryl bond cleavage. Metathe- tical reactions involving alkali metals and silver salts have been employed to replace selectively either CI or Br ions of the mtxed halides to yield a series of rnlxed triaryl-arsenic and -antl- 1D0nyhalides and pseudohalides.
RIAR~L halides of the type Ar3MX2 (M = reported method-". Iodine monochloride (Fluka) As, Sb) of group VB elements are readily was distilled and cyanogen iodide (Eastman Organic T formed by the addition of halogen to the Chemicals) recrystallized before use. Thiocyanogen corresponding tertiary triaryl derivatives'. Corres- was freshly generated in situ by the method reported ponding mixed halides of the type Ar3MXY are earlier from this laboratory'', Acetonitrile used mostly known for the phenyl series which have been as the reaction medium was dried Over P20S and briefly reported to be formed in varying yields from distilled before use. the oxidative addition of XY (where XY = IC12, Reactions were carried out under strict anhydrous I Br3.4, TCN5, BrCN8, (SCN)2' to Ph3M. conditions in a dry nitrogen atmosphere. Freshly In continuation of our studies on the relative prepared silver salts were dried before each reaction reactivity of group IVB metal-carbon bond towards while alkali metal salts (AR grade) were used as such electrophiles (XY) as pseudohalogens", inter- such. halogens", cyanohalides-", and of our interest in the A few representative reactions are described formation of diaryl-tin-t, and -lead12 mixed halides below. The data of addition reactions are summa- of the type Ar2SnX'Y or Ar2PbXY, we now report rized in Table 1 while those of exchange reactions the action of these electrophiles (XY) towards in Table 2. . triphenyl and trie·p-tolyl-arsenic, antimony and Reacti()'fl,of(P-tolyl)aSb with lei (1:1)-A solution bismuth compounds. of ICI (1'23 g, 0·0075 mole) in acetonitrile (50 ml) Parallel reactions with (SCN)2 generated in situ was slowly added during 1 hr to a well-stirred cold are also discussed. (-5°) suspension of (P-tolylhSb (3 g, 0·0075 mole) Metathetical reactions involving alkali-metal and in acetonitrile (200 ml}. The initial blood-red colour silver salts (M'Z where M'= Ag, K; Z = SCN, NCO) of ICI solution disappeared immediately after each in acetonitrile have successfully been employed addition. Towards the end of the reaction the to replace selectively either Cl or Br ions of the colour of the solution changed into light yellow. mixed halides. The compounds have been cha- The mixture was further stirred for 1 hr to ensure racterized by analytical data, and IR absorptions the completion of the reaction. The solvent was associated with the pseudohalogen group are also distilled off and the residue recrystallized from discussed. petroleum ether (b.p, 60-80°) to yield (P-tolylhSb ICI (3'86 g, 91%), m.p. 190-92° (Found: C, 45·16; Materials and Methods H, 4·01. C21H21SbICl requires C, 45·24; H, 3·79%). Triphenyl- and tr~-p-tolyl-arsenicl3'H, ~nd Reaction of (P-tolyl)aAs with (SCN)2 (1: 1)- A _antimony15.16, were obtamed by the Wurtz reaction freshly prepared solution of (SCN)2 (1·1 g, 0·0086 of the anhydrous metallic trihaJides and the .appro- mole) in acetonitrile (25 ml) was added to a stirred pria te aryl halides in refluxll:g be~zene in the solution of (P-tolyl)3As (3-2 g, 0·0086 mole) in aceto- 0 presence of sodium. The tnaryl-~lsmuth were nitrile (200 ml) at-5 • The reaction mixture was obtained by Grignard'", or by aryllithiumw reag~nts. subsequently stirred in dark for 4 hr and the yellowish Iodine mono bromide was prepared and punfied white solid containing a little polymerized (SCN)2' by the procedure developed in. our labora.tory9. which also separated out was washed with cold Cyanogen bromide was also obtained by previously acetonitrile and dried, After recrystallization from petroleum ether (60-80°) the white solid was cha- •To whom correspondence should be addressed. racterized as (p-tolyl)3As(SCN)2 (3-15 g, 78%), m.p .
778 BHATTACHARYA & SINGH: MIXED TRIORGANO GROUP VB HALIDES
TABLE 1- REACTIONSOF TRIORGANO-ARSENICAND -ANTIMONYCOMPOUNDSWITH XY (1: 1)
AraM AraMXY Yield m.p. Found (Calc.) (%) % (0C) Ar M C H . XY = ICI
Ph As PhaAsICI 64 101 45·98 (46,13) 3·41 (3'22) Ph Sb PhsSbICI 90 158 (158)2 - - p-Tolyl As (p- TolyilaAsICI 80 112 49·21 (49,39) 4'26 (4,14) XY = IBr
Ph As Ph3AsIBr 70 154 (15S)3 Ph Sb PhsSbIBr 72 214 (215)4 p-Tolyl As (P- TolyllsAsIBr 90 175 45·21 (45-43) 4·12 (3'81) p-Tolyl Sb (P- TolyllsSbIBr 86 180 41'28 (41·90) 3-64 (3-51) XY = ICN
Ph As Ph3AsICN 84 110 (110-12)6 Ph Sb Ph3SblCN 80 173 (174)6 p-Tolyl As (P-Tolyl)3AsICN 78 124 52-65 (52,71) 4·36 (4'22) p-Tolyl Sb (P- TolylJsSblCN 74 188-90 48,12 (48'21) 3-96 (3-86) XY = BrCN
Ph As Ph3AsBrCN 75 139 (140)6 Ph Sb Ph3SbBrCN 84 >220 48·68 (49'71) HI (3'29) p-Tolyl As (P- Tolyl)3AsBrCN 72 204-5 57·98 (58'17) 4·72 (4-65) p-Tolyl Sb (P- Tolyl)sSbBrC}' 84 >220 52,58 (52·73) 4·36 (4,22) XY = (SCNh
Ph As Ph3As(SCNh 72 108 (110)7 Ph Sb Ph3Sb(SCN)2 76 104 (105-6)7 p-Tolyl Sb (p- TolyllaSb(SCNh 83 148 53'98 (54'02) 4·24 (4'13)
TABLE 2 - EXCHANGEREACTIONSOF Ar3MIX WITH K AND Ag SALTS (M'Z) (1: 1)
Ar3MIY ArsMIZ Yield m.p. Found (Calc.) (%) % CC) C H M'Z = KNCO
Ph3AsICI PhaAsINCO 90 85 47·98 (48'02) 3'29 (3'18) Ph3AsIBr PhsAsINCO 75 85 - PhsSblBr Ph3SblNCO 72 >225 43-68 (43'71) 2·96 (2-89) (P-TolyllaAsICl (P-Tolyl)sAsINCO 70 113-14 50·98 (51'08) 4-13 (4,09) (P- Tolyl)aAsIBr (P- TolyllsAslNCO 70 113-14 - (P- TolyilaSbICI (P-Tolyl)3SbIKCO 75 >230 46·72 (46'84) 3-81 (3,75) (P-Toly1lsSbIBr (P- TolylJsSblN CO 70 >230 M'Z = AgNCO
PhsAsICI PhsAsIKCO 85 85 PhsAsIBr PhsAsINCO 70 85 PhsSbICI ph3SblNCO 72 >225 PhsSblBr PhsSbINCO 75 >225 (P-Tolyl)sAsICI (P-Tolyl)'AsIKCO 76 114 (P-Tolyl)aAsIBr (P-Tolyl)aAsINCO 79 114 (P-TolyllsSbICI (P- Toly1lsSbINCO 75 >230 (P-Tolyl)sSbIBr (p-Tolyl)sSbINCO 86 >230 M'Z= KNCS
Ph3AsICl Ph3AsINCS 79 148-49 46·31 (46'45) 3,22 (3'07) PhsAsIBr PhsAsINCS 70 148-49 PhsSbICI Ph3SbINCS 76 82-83 42·32 (42-41) 2'93 (2-81) Ph,SbIBr PhsSbINCS 70 82-83 (P- Tolyl)3AsICl (P- TolyllsAslNCS 60 118 49-48 (49,54) 4,05 (3-96) (P-TolylJsAsIBr (P- TolyllsAsl~ CS 66 118 (P- Tolyl)3SbICl (P- Tolyl)sSblNCS 90 202 45-41 (45'54) 3·71 (3-64) (p- Tolyl)3SbIBr (p-Toly1lsSbINCS 67 202
779 INDIAN J. CHEM., VOL. 16A, SEPTEMBER 1978
158-60° (Found: C, 59·36; H. 4·61. C~3H21AsS2N2 reactions of group IVB metals where identically requires C, 59'47; H, 4·55%). placed iodide is more readily replaced by silver
Reaction of Ph3SbICl with KNOC (1: 1)- Ph3SbICI salts, and the chlorides, bromides are replaced by (3·1 g, 0·0058 mole) was added to a suspension of the anions attached to the alkali meta122. In fact an excess (0·47 g, 0·0058 mole) of anhydrous KNCO this forms one of the ready source for Obtaining in acetonitrile (100 ml). The reaction mixture was triorgano group IV metallic derivatives. refluxed for 5 hr. A white precipitate of KCI sepa- It may be added that the iodine halides", cyanogen rated out, which was filtered and the solvent dis- halides-", and even the thiocyanogen", on the re- tilled off to give a residue which recrystallized from action with symmetrical tetra aryl group IVB metallic pet. ether (b.p, 60-80°) and identified as PhaSblNCO derivatives (Ge, Sn, Pb) behave as electrophillic (2'76 g, 91%), m.p. >225° (Found: C, 43-58; reagents and cleave the metal-aryl bond(s) to H, 2·96. CI,HIsSbINO requires C, 43·71; H, different extent depending upon the relative 2·89%). strength of electrophiles and also of the metal-aryl Reaction of PhsBi with [CN (1: 1)-A solution bonds. of ICN (1·38 g, 0·0090 mole) in acetonitrile (40 ml) The triorgano mixed halo derivatives containing was gradually added to a cold solution (-10°) of pseudohalides were also identified through their PhaBi (4·1 g, 0·0090 mole). The reaction mixture characteristic IR absorption. The vibrations asso- was allowed to attain room temperature and subse- ciated with the asymmetric stretching of a cyanide quently stirred for a further period of 1 hr. The group were invariably observed .-;2080-2100 cm=. solvent was distilled off under reduced pressure to The corresponding asymmetric stretching of the yield white crystals of Ph2BiCN (3·1 g, 87%), m.p. isocyanate (-NCO) and isothocyanate (-NCS) 210° (d) (lit.lt m.p. 210° d.). The filtrate gave on were also observed -..2180-2200 and 2020-2060 cm-1 distillation a colourless liquid (1·25 g, 69%), b.p. respectively. These vibrations are in good agree- 63.65°/10 mm (lit.20 b.p. 184-86°) whose IR spectrum ment with those reported earlier from triaryl di- was identical to that of an authentic sample pseudohalides and related products of these metals'", of PhI. which suggest that they are nitrogen-bonded to the Results and Discussion central metal atom, similar to the corresponding group IVB organometallic derivatives", which have Iodine and cyanogenmonohalides (ICl, IBr, ICN, also been shown to be nitrogen-bonded. BrCN) were found to add oxidatively under mild reaction conditions to symmetrical triaryl tertiary- Acknowledgement arsines and -stibines (III) to give excellent yields We are thankful to the CSIR, New Delhi, for (d. Table 1) of corresponding triorgano arsines and the award of a junior research fellowship to one stibines (V) derivatives of the type Ar M3\XY. No of us (M.S.). trace of any aryl halides (ArX) or of Ar2MY, the products normally expected from the possibility References of metal-aryl bond cleavage were observed in the 1. DOAK, G. O. & FREEDMAN, L. D., Organometallic com- reactions. pounds of arsenic, antimony and bismuth (John Wiley, Triarylbismuth dihalides-, except the i?dides New York), 1970. (whose existence have only been speculated In the 2. DOAK, G. O. & LONG, G. G., Trans. N. Y. Acad. Soc., 28 (1966), 402. vapour state) are well known. Attempts to pre~are 3. BEVERIDGE, A. D. & HARRIS, G. S.,]. chem, Soc., (1964), triarylbismuth mixed halo derivatives, Ar2~IlX 6076 through oxidative .addition of ICI. or ICN failed, 4. BEVERIDGE, A. D. & HARRIS, G. S. & INGLIS, F., J. chem, Soc, (1966), 520. The products obtained were Ar2BIX 6X=C!, CN) S. WILKINSON, J. F. & CHALLENGER, F., ] chem, Soc. and ArI indicating cleavage of monoaryl-bismuth (1924), 854. bond in' preference to the oxidation reaction .. I.n 6. STEINKOPT, W. & SCHWEN, G., Ber. dt. chem, Ges., 54 this respect these iodine halides act as electrophIlhc (1921), 2799. 7. CHALLENGER, F. A., SMITH, L. & PATON, F. j.. j. chem, reagents being polarized in the direction I+X- and Soc., (1923), 1046. attacking the Bi+-Ar- ~o~d. A fo~r-centred mecha- 8. BHATTACHARYA, S. N., PREMRAJ & SRIVASTAVA, R. C., nism8-I2 proposed for SImilar reactions .of group I':'B ]. organometal, Chem., 87 (1975). 279. compounds readily explain the formation of Ar2BtX 9. BHATTACHARYA, S. N., PREMRAJ & SRIVASTAVA, R. C., ]. organometal. Chem., 105 (1976). 45. and ArI. 10. BHATTACHARYA, S. N. & PREMRAJ, Indian J. Chem., Such an observation is in line with the fact that (in press) the M-C bond energy in the triaryl compound of 11. BHATTACHARYA, S. N. & PREMRAJ, Paper presented at group VB decreases in the order As-C>Sb-C>Bi-C21. the International conference on organometallic com-pounds and coordination chemistry of Ge, Sn, Pb, Nottingham, Triorgano dihalides of group VB el.e~ents almost England. . invariably form the source for obtaining p.roducts 12. BHATTACHARYA, S. _T. & PREMRAJ, j. inorg. wucl. Chem., containing other anions through metathetical re- (in press). 13. SHRINER, R. L. & WOLF, C. N., Org. Syn. ColI. Vol. 4 actions involving metallic saltsl.. Similar meta- (1963), 910. thetical reactions were successful WIth the tnorgano 14. TROTTER, J., Can. J. Chem., 40 (1962), 1878. mixed dihalides mentioned above to obtain other 15. OLIFIRENKO, S. P., Chem Abstr.,63 (1965). 8401. series of mixed products. It was observed that 16. MICHAELIS, A. & GENZKEN, D., Liebigs Ann., 242 (1887), 164. the halides other than iodide in Ar3MIY were. ex- 17. BLICKE, F. F., OAKDALE, V. O. & SMITH, F. D., j. Am. clusively replaced by the anions ~f the al~ah ~r chem. Soc., 53 (1931). 1025. silver salts to yield Ar3MIZ. ThIS beh:,-vI~ur. IS 18. ZHITKOVA, L. A., SHEVERDINA, N. 1. & KOCHESHKOV, somewhat different from those observed In SImilar K. A., Chern. Abstr., 33 (1939), 5819.
780 BHATTACHARYA &: SINGH: MIXED TRIORGANO GROUP VB HALIDES
19. CHALLENGER,F. & ALLPRESS,C. F., J. chem, Soc., (1915), by F. G. A. Stone & R. West (Academic Press, New 16. York), 1964, 49. -_20. VOGEL, A. I., Practical organic chemistry (Longmans, 22. PaLLER, R. C., The chemistry of organotin compounds London), 1971, 538. (1970). _21. SKINNER, H. A., The strength of metal to carbon bonds, in 23. GOEL, R. G. & RIDLEY, D. R., Inorg. Chem., 13 (1974), Advances in organometallic chemistry, Vol. 11 edited 1253.
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