A PHOSPHINE COMPLEX OF BISMUTH(III) - X-RAY CRYSTAL-STRUCTURE OF [PME3H][BI2BR7(PME3)2]

The reaction between BiBr3 and one equivalent of PMe3 in THF affords, after recrystallisation from MeCN/Et2O, yellow crystals of [PMe3H][Bi2Br7(PMe3)2] . 2 (MeCN) (1), which has been characterised by X-ray crystallography. Compound 1 is the first reported bismuth-phosphine complex and comprises a polymeric anion, the monomeric unit of which contains a planar Bi2Br6 core, each bismuth being further bonded to a PMe3 ligand and an additional bromide such that the bismuth resides in an octahedral coordination environment. The latter bromides form linear bridges between monomeric units; the phosphines are trans with respect to the Bi2 unit, with a Bi-P distance of 2.762(3) angstrom. The reaction between BiI3 and PEt3 in THF affords, after recrystallisation from MeCN/Et2O, orange crystals of [PEt4]4[Bi6I22] (3) which has also been characterised by X-ray crystallography.