VII-K Synthesis of Compounds Having a Novel Bonding Containing Heavier Main Group Elements

The chemistry of complexes with diatomic chalcogen ligands has attracted much attention due to their unique structure, biological interest, potential for hydrogen-transfer catalysis, and synthetic utility as a precursor of new metal cluster complexes. However, since sulfur and selenium ligands have a strong propensity for bridging metal atoms, it is often difficult to prepare their mononuclear diatomic complexes. To our knowledge, the disulfur and diselenium complexes of platinum remain unknown, although the dioxygen analogues, e. g., [(Ph3P)2PtO2], have been extensively studied. When platinum dichlorides 1a,b were reduced by an excess of lithium naphthalenide in THF and the resulting platinum(0) species [(ArMe2P)2Pt] (2a,b) were successively treated with elemental sulfur (3 equiv. as S) and elemental selenium, the first platinum disulfur and diselenium complexes [(ArMe2P)2PtE2] (3a,b: E = S; 4a,b: E = Se) were obtained, respectively. The structures of 3a,b and 4a,b were identified by mass spectrometry, elemental analysis, and multinuclear NMR spectroscopy, and the molecular structures of 3b and 4b were finally determined by X-ray crystallographic analysis. The molecular structures of 3a,b and 4a,b are very similar, and these complexes have a square-planar geometry and a three-membered PtE2 (E = S, Se) ring as well as an analogous dioxygen complex [(Ph3P)2PtO2]. Figure 1. ORTEP drawing of a disulfur complex of platinum 3b.