platinum-oxygen bond formation: kinetic and mechanistic studies

Reaction of [ptme(c^n)(sme2)] (c^n = 2-phenylpyridinate (ppy); 1a, c^n = benzo[h]quinolate, (bhq); 1b) with hydrogen peroxide gives the platinum(iv) complexes trans-[ptme(oh)2(c^n)(h2o)] (c^n = ppy; 3a, c^n = bhq, 3b) bearing platinum-oxygen bonds. the pt(ii) complexes 1a and 1b have 5dπ(pt)→π*(c^n) mlct band in the visible region which is used to easily follow the kinetic of its reaction with h2o2. the kinetics and mechanism of pt-o bond formation have been experimentally and theoretically investigated, showing the simple second-order kinetics; rate = k2[h2o2][pt(ii) complex]. the pt(iv) products were characterized by nmr spectroscopy and elemental analysis. the geometries and the nature of the frontier molecular orbitals of pt(iv) complexes containing pt-o bonds were also studied by means of the density functional theory. complex 3b is unstable during the crystallization process in ch2cl2/acetone and gives the binuclear complex [pt2me2(cl)2(μ-oh)2(bhq)2], 4.