Triphenylbismuth complexes

Physical properties of a number of organobismuth complexes have been compiled. The triaUcylbismuth compounds are generally very oxygen sensitive, though stable to moisture. Many triarylbismuth compounds are air stable as well as stable to moisture. The triaUcyls with small R groups are colorless liquids, which may be distilled imder vacuum. Triphenylbismuth is a commercially available, air stable, white crystalline solid. 

In the case of polyhydroxylic phenols, perphenylation occurred. Thus, phloroglucinol (28) reacted with triphenylbismuth carbonate to give a mixture of 2,4,6-triphenylphloroglucinol (29) and 2,2,4,5-tetraphenylcyclopent-4-en-l,3-dione (30).24 The dione (30) is formed from (29) by phenylation, decarboxylation and oxidation. When a large excess of triphenylbismuth carbonate (5 mol equiv.) was used, the dione (30) was the only isolated product in 60% yield. In contrast, the reaction of phloroglucinol with pentaphenylbismuth led to a complex mixture.25... 

Triphenylbismuth difluoride has been synthesized by thermal decomposition of a cationic triphenylbismuth(V) complex [Ph3Bi(OAsPh3)2][Bp4]2 in dichloromethane [731C944]. Tetraphenylbismuth tribromide is transformed thermally to triphenylbismuth dibromide [52LA(578)136], while tetraphenylbismuth triphenylsiloxide is readily cleaved by HCl to give triphenylbismuth dichloride [75DOK(225)581]. 

Pentacoordinate cationic complexes of the type (Ph3BiL2)Y2 can be prepared by the reaction of triphenylbismuth dichloride with a silver salt AgY in the presence of a ligand molecule L [73IC944]. These complexes are stable in the solid state, but decompose in solution. Triphenylbismuth difluoride is formed from the thermal decomposition of [Ph3Bi(OAsPh3)2][BF4]2. 

Treatment of anhydrous oxybis(triphenylbismuth) perchlorate with oxygen-donor bases results in the formation of pentacoordinate cationic complexes [73IC944]. Dimethyl sulfoxide, pyridine iV-oxide, triphenylphosphine oxide and triphenylarsine oxide are commonly employed ligands. 

Anhydrous oxybis(triphenylbismuth) diperchlorate and triphenylphosphine oxide were mixed in a 1 2 molar ratio in absolute alcohol. The solution was allowed to stand overnight. Dropwise addition of petroleum ether (b.p. 35-60°C) until the solution became turbid, followed by refrigeration, gave the product as crystals. The complex was recrystallized from absolute alcohol containing free ligand, washed successively with benzene and petroleum ether, and dried in vacuo [73IC944]. 

Iododibenzobismole 331 lododiphenylbismuthine 199, 204 Lithium hexaphenylbismuthate 304 Mesitylene-bismuth chloride cr-complex 207 4-Methoxyphenylbis(4-methylphenyl)bismuthine 29 Methyl bis(4-methyl-l-naphthyl)bismuthinate 319 Methylbis(4-methylphenyl)bismuthine 34 Methylbismuth bis(O-alkyldithiocarbonate) 123 Methylbismuth dithiolates 122 Methylbis(2,4,6-triisopropylphenyl)bismuthine 24 (4-Methylphenyl)triphenylbismuthonium tetrafluoroborate 288 1-Methyltetrahydrobismole 335 Oxybis(triphenylbismuth) bis(benzenesulfonate) 281 Oxybis(triphenylbismuth) dicyanate 280 Oxybis(triphenylbismuth) diperchlorate 279... 

Triphenylbismuth is a very weak Lewis base. In contrast to Ph3M (M = P, As, Sb) only a few complexes with transition metals have been prepared. 

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