Synthesis and X-ray crystal structure of the bridging diselenide complex [(PtMe 3 Br) 2 MeSeSeMe], and unusual prochirality at a selenium centre in the complex [PtMe 3 Br(Me 2 Se) 2 ]

The tetrameric bromotrimethylplatinum [(Me3PtBr)4] reacts with dimethyl diselenide and dimethyl selenide to form respectively the dinuclear complex [(Me3PtBr)2MeSeSeMe] and the mononuclear complex [Me3PtBr(Me2Se)2]; the crystal structure of the dimer shows a novel diselenide bridge, and the atomic inversion about selenium has been studied in both complexes exploiting the presence of anisochronous methyl groups.