Pentaphenylbismuth
Chemical compound
From Wikipedia, the free encyclopedia
Pentaphenylbismuth is an organobismuth compound with formula Bi(C6H5)5, often abbreviated as BiPh5, where Ph stands for phenyl. It is a violet crystalline solid. A molecule of pentaphenylbismuth consists of five phenyl groups attached to one bismuth atom. In this compound, bismuth is hypervalent.
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| Names | |
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| Preferred IUPAC name
Pentaphenyl-λ5-bismuthane | |
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| Properties | |
| Bi(C6H5)5 | |
| Molar mass | 594.510 g·mol−1 |
| Appearance | Violet crystals |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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History
Pentaphenylbismuth was prepared by Georg Wittig et al. and his coworker K. Clauss in 1952.[1]
Synthesis
Pentaphenylbismuth can be synthesized by reaction of triphenylbismuth dichloride with phenyllithium.[2]
- Ph3BiCl2 + 2 PhLi → BiPh5 + 2 LiCl
Triphenylbismuth dichloride itself can be synthesized by oxidation of triphenylbismuth by sulfuryl chloride.[3]
- BiPh3 + SO2Cl2 → Ph3BiCl2 + SO2
Structure
A strong violet color and strong dichroism of pentaphenylbismuth are very unusual for a compound of a main-group element. Bismith's lighter congeners, like antimony, never displays such behavior, nor when the bismuth's symmetry is D3h. The X-ray structure analysis done at −96 °C (−141 °F) shows that Bi(C6H5)5 has a square pyramidal molecular geometry and is thus very similar to the colorless Sb(C6H5)5, which also has the same molecular geometry.[4][1]
Uses
Reactions
Pentaphenylbismuth reacts with sulfur dioxide to give diphenylsulfone under mild conditions in high yield.[6]
Pentaphenylbismuth easily forms a bismuthonium cation, for example by reaction with p-toluenesulfonic acid:[7]
- BiPh5 + ArSO2OH → [BiPh4]+[ArSO3]−
Pentaphenylbismuth forms an ate complex upon reaction with phenyl lithium:[8]
- BiPh5 + PhLi → Li+[BiPh6]−