Interaction of heterocyclic thioamides with tellurium(II) and tellurium(IV). Syntheses and crystal structures of bis[2-(2-thioxo-1,3- thiazolidin-3-yl)-4,5-dihydro-1,3- thiazolium]hexabromotellurate(IV) and tris(1- methylimidazole-2-(3H)-thione)tellurium(II) bromide

Abstract Reaction of 1,3-thiazolidine-2-thione with tellurium(IV) in hydrobromic acid medium gave the hexabromotellurate, [C 6 H 9 N 2 S 3 ] 2 2+ [Te IV Br 6 ] 2− ( 3 ). Reaction of 1-methylimidazoline-2-(3H)-thione (L″) with tellurium(IV), in hydrobromic acid medium, gave the mixed-ligand tellurium(II) complex [Te II L″ 3 Br] + Br − ( 4 ). The structures of [C 6 H 9 N 2 S 3 ] 2 2+ [Te IV Br 6 ] 2− ( 3 ) and [Te II L″ 3 Br] + Br − were determined by single crystal X-ray diffraction methods. In 3 the unit cell contains [TeBr 6 ] 2− anions and two [C 6 H 9 N 2 S 3 ] + cations. There is no direct bonding between the metal atom and the cations. In the anion only slight angular deviations from the perfect octahedral geometry are observed. The lone pair of electrons on tellurium(IV) is found to be stereochemically inert. In the cation the two five-membered heterocyclic rings adopt different conformations. In complex 4 , in the solid state, the planar [Te II L″ 3 Br] + cation and Br − anion are held together by ionic interactions. In the cation, L″ is bonded to the central tellurium atom through the sulphur atom.