C(sp2)–C(sp2) Reductive Elimination from a Diarylplatinum(II) Complex Induced by a S–S Bond Oxidative Addition at Room Temperature

The synthesis and characterization of three six-coordinated Pt­(IV) complexes with the stoichiometry [Pt­(Ar)2(S∧N)2] (S∧N = Sbt, benzothiazole-2-thiolate, Ar = p-MeC6H4 (1a), C6F5 (1b); S∧N = Spy, 2-pyridinethiolate, Ar = p-MeC6H4 (1c)) is described. Of these, 1a undergoes, at room temperature and within 18 h, a remarkable C–C reductive elimination process between the aryl ligands to give, as the final products, the stable binuclear lantern complex [Pt2(Sbt)4] (2a) and 4,4′-dimethylbiphenyl. Differently from 1a, solutions of 1b,c are indefinetively stable up to 60°C and do not undergo reductive elimination. Complexes 1a–c and 2a were characterized by IR and NMR spectroscopy, high-resolution mass spectrometry, and single-crystal X-ray crystallography (1b,c and 2a). 1H–19F HOESY experiments on 1b demonstrated the presence of a “through-space” coupling between proximal F and H atoms of the molecule that are separated by six bonds but are in close spatial proximity.