Synthesis and properties of bis(1,3-dithiole-2-thione-4,5-dithiolato)bismuthate(1-) salts, [Q][Bi(dmit) 2]. Crystal structure of [AsPh 4][Bi(dmit) 2]·1/2DMSO: comparison of the solid state structures of [Q][Bi(dmit) 2] and [Q][Sb(dmit) 2

Abstract

Ionic complexes, [Q][Bi(dmit) 2] ( 5:QNEt 4, NBu 4, 1,4-Me 2-pyridinium and AsPh 4), have been obtained from BiBr 3 and [Q] 2[Zn(dmit) 2] [H 2–dmit4,5-dimercapto-1,3-dithiole-2-thione]. As established by the crystal structure determination of [( 5:QAsPh 4)·1/2DMSO], the cations have near tetrahedral geometries and are well separated from the anions. The anions, containing chelating dmit ligands, are linked into chains via Bi–thiolato–S inter-anion bonds: Bi 2S 2 rings are formed within the chains, with Bi⋯Bi distances alternating between 3.7760(3) and 3.9092(3) Å. The bismuth atoms are six-coordinate, arising from two inter-anion Bi–S [Bi–S=3.0391(13) and 3.1643(14) Å] and four intra-anion Bi–S bonds [between 2.6680(13) and 2.8370(13) Å], with stereochemistries, including the equatorial-sited stereochemically active lone pair, of distorted pentagonal bipyramids. There are no S⋯S contacts between the anions less than the sum of the van der Waals radii. Comparisons are made between the structure of [( 5:QAsPh 4)·1/2DMSO] and those reported previously for ( 5:QNEt 4), [( 5:QNEt 4)·1/2Et 2O] and [( 5:QNBu 4) as well as those for [Q][Sb(dmit) 2] ( 4).