The first platinum disulfur and diselenium complexes,[Pt (S 2)(ArMe 2 P) 2](Ar= Tbt (4a), Bbt (4b)) and [Pt (Se 2)(ArMe 2 P) 2](Ar= Tbt (5a), Bbt (5b)), have been synthesized by the reactions of the corresponding overcrowded platinum (0) complexes [Pt (ArMe 2 P) 2] with elemental sulfur and selenium. Molecular structures of 4b and 5b were established by X-ray crystallographic analyses, which show a novel three-membered PtE 2 (E= S, Se) ring ...