From tertiary bismuthines

In marked contrast to the ease of access of lighter pnictogen congeners, quaternary bismuth compounds are not usually accessible by direct interaction of triarylbismuthines with alkylating agents due to the low nucleophilicity of the bismuthines, whose unshared electron pair is of a strong y character. 

However, there are a few known quaternary bismuth compounds that can be prepared with this methodology. Tetramethylbismuthonium triflate, which is the only known tetraalkylbismuth compound, is synthesized by the reaction between trimethylbismuthine and methyl triflate in acetonitrile [94AG(E)976]. The tritium-labeled phenyl cation, generated from the 

Compound Synthetic Yield %) M.p. (°C) method Physical data Reference 

Trimethylbismuthine (1.25 g, 4.9 mmol) in acetonitrile (2 ml) was treated with methyl trifluoro-methanesulfonate (0.9 g, 5.5 mmol) under an argon atmosphere. The mixture was stirred for 6 h at room temperature and then evaporated to dryness under a high vacuum to obtain the bismuthonium triflate as a colorless solid (1.5 g), which was purified by reciystallization from acetonitrile-ether [94AG(E)976]. 

Tetraorganylbismuth compounds are mostly soluble in chloroform, dichloromethane and acetonitrile, slightly soluble in benzene and THF, and almost insoluble in hexane and diethyl ether. Protic and aprotic polar solvents 

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Although trialkyl- and triarylbismuthines are much weaker donors than the corresponding phosphoms, arsenic, and antimony compounds, they have nevertheless been employed to a considerable extent as ligands in transition metal complexes. The metals coordinated to the bismuth in these complexes include chromium (72—77), cobalt (78,79), iridium (80), iron (77,81,82), manganese (83,84), molybdenum (72,75—77,85—89), nickel (75,79,90,91), niobium (92), rhodium (93,94), silver (95—97), tungsten (72,75—77,87,89), uranium (98), and vanadium (99). The coordination compounds formed from tertiary bismuthines are less stable than those formed from tertiary phosphines, arsines, or stibines. 

Other methods of preparing tertiary bismuthines have been used only to a limited extent. These methods iaclude the electrolysis of organometaUic compounds at a sacrificial bismuth anode (54), the reaction between a sodium—bismuth or potassium—bismuth alloy and an alkyl or aryl haUde (55), the thermal elimination of sulfur dioxide from tris(arenesulfiaato)bismuthines (56), and the iateraction of ketene and a ttis(dialkylainino)bismuthine (57). 

There is a report154 of Ph2Bi being formed from Ph2BiI and Na/liq. NH3, but instability complicates synthetic utility. Very little is known about tertiary bismuthines, although Ph3Bi is available. 

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