Organobismuth-halogen compounds

It has been illustrated by structural studies that the organobismuth halides tend to self-organize in the solid state. Their number is, however, limited to simpler representatives. Sterically demanding groups probably prevent association. 

Other structurally characterized monoorganobismuth halides include PhBiC - 

The same workers [452-454] described the structure of anionic PhBiXs (X = Br, I) which are halogen bridged dimers, 192 and 193. Not unexpectedly, the diphenyldi-halo anions [Ph2BiX2] are pseudo-trigonal bipyramidal monomers (unassociated). 

A chain-like polymeric self-organization, 194, is observed in Tr-cyclopentadienyl bismuth dichloride, C5H5BiCl2. Pseudorotational disorder results in a mixture of and bonding of the C5H5 ring to the metal atom. The chains are formed by double chloride bridging and the bismuth-chlorine interatomic distances differ [455]. 

The three xylene derivatives, C6H4(CH3)2-BiCl3, are self-organized in chain 

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In a manner similar to phosphoms, arsenic, and antimony, the bismuth atom can be either tri- or pentacovalent. However, organobismuth compounds are less stable thermally than the corresponding phosphoms, arsenic, or antimony compounds, and there are fewer types of organobismuth compounds. For example, with R MX, R3MX2, R2MX3, and RMX, where M is a Group 15 (VA) element and X is a halogen, only the first two types have been prepared where M = Bi, but all four types are known where M = P, As, or Sb. 

The range of organobismuth compounds is rather restricted. The trialkyls and triaryls can be prepared by the Grignard method. Trimethylbismuth is spontaneously inflammable in air. It reacts with halogens by substitution, rather than by addition. 

Functionally-substituted organobismuth compounds have been obtained (Scheme 4). Halogens cleave both Bu—Bi and Ph—Bi bonds in PhgBuBi (prepared from PhgBuCl and BuLi). Compounds, Ph2AsC(OH)RH have been produced from RCHO and PhgAsX (X=Li or H). In solution, equilibrium (2)... 

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