New Organyltriphenylphosphonium Hexabromoplatinates [Ph₃PR]₂[PtBr₆], R = CH₃, CH=CH₂, CH₂CH=CH₂

Abstract—A series of compounds [Ph₃PCH₃]₂[PtBr₆] (I), [Ph₃PCH=CH₂]₂[PtBr₆] (II), [Ph₃PCH₂CH=CH₂]₂[PtBr₆] (III) have been synthesized to extend the knowledge about ionic hexabromo-containing platinum (IV) complexes promising as catalysts of chemical reactions and bioactive components. Complexes I–III represent red crystals formed from potassium hexabromoplatinate and organyltriphenylphosphonium bromides in acetonitrile with a yield of 90–94%. The structure of the synthesized complexes was determined by X-ray diffraction and IR spectroscopy. Crystals of complexes I–III contain tetrahedral phosphonium cations. The tetrahedral configuration of cations approaches an ideal value. In hexabromoplatinate octahedral anions, the BrPtBr trans-angles are 180° and the cis-angles are close to the theoretical value of 90°. The structure of crystals is formed by weak hydrogen bonds Br^…H–C between cations and anions.