C–H activation of benzene by platinum(II) complexes with cyclometalated phosphine ligands

The bulky phosphine ligands di-tert-butyl(1-naphthyl)phosphine (1) or di-tert-butyl(N-indolyl)phosphine (2) react at room temperature with [(μ-SMe2)PtMe2]2. Coordination of the phosphine and C–H bond activation at an sp2 carbon of the ligand with the release of methane takes place to form the PC cyclometalated products [(PC)PtMe(SMe2)] (3 or 4, respectively). The cyclometalated complexes 3 and 4 have both been characterized by X-ray crystallography. Complexes 3 and 4 were each observed to undergo intermolecular activation of arene C–H bonds. Upon thermolysis in benzene, complexes 3 and 4 react to eliminate methane and yield isolable platinum(II)–phenyl complexes.