Coordination complexes of the bismuth(III) thiolates Bi(SC6F5)3 and Bi(SC6Cl5)3 with pyridine ligands

The chloro-aryl bismuth thiolate Bi(SC6Cl5)(3) has been prepared from the reaction between BiPh3 and the thiol HSC6Cl5 by analogy with the previously described synthesis of the fluoro-aryl species Bi(SC6F5)(3). The compound Bi(SC6Cl5)(3) is only sparingly soluble but can be isolated as a dmf adduct [Bi(SC6Cl5)(2)](dmf) (dmf=N,N-dimethylformamide) which adopts a five-coordinate square-based pyramidal geometry in which the two dmf ligands lie in the basal plane with a mutually cis configuration. Treatment of either Bi(SC6F5)(3) or Bi(SC6Cl5)(3) with pyridine or 2,2'-bipyridyl: ligands affords the coordination complexes fac-[Bi(SC6F5)(3)(py)(3)] (two crystalline polymorphs), fac-[Bi(SC6Cl5)(3)(py)(3)],fac-[Bi(SC6F5)(3)(4-pic)(3)] (4-pic=4-picoline), [Bi(SC6Cl5)(3)(4-pic)(2)] [Bi(SC6F5)(3)(bipy)] (bipy=2,2'-bipyridyl), [Bi(SC6CL5)(3)(bipy)] [Bi-2(SC6Cl5)(6)(2-pic)(3)] (2-pic=2-picoline) and [Bi(SC6F5),(4-pic)]. Five- and four-coordinate complexes adopt square-based pyramidal and equatorially vacant, trigonal bipyramidal (disphenoidal) geometries respectively, the former having the two ligands cis to each other in the basal plane. The compound [Bi-2(SC6Cl5)(6)(2-pic)(3)] contains both five- and four-coordinate mononuclear units. A salt with the formula [4-picH][(4-pic)(2)H][Bi-3(SC6F5)(11)] was also isolated in which the anion contains a central bismuth bonded to five thiolate ligands with a square-based pyramidal geometry. Two cis-basal thiolates act as bridging groups to two outer bismuth centres each of which is four-coordinate with the expected disphenoidal geometry in which the bridging thiolate is in an axial position. The structure of the dinuclear arylbismuth thiolate compound [Bi2Ph2(SC6F5)(4)(4-pic)(2)] is also described, Intramolecular conformations and intermolecular associations in all structures are dominated by pi-pi-interactions.