Organoplatinum(iv) tris-chelate complexes, each having a cyclic metallacarbonate ring: synthesis, characterization and kinetic studies of the formation

Abstract

The complexes [Pt{(CH₂)₄}(NN)], 1a (NN = 2,2′-bipyridine) and 1b (NN = 1,10-phenanthroline) react with 2,3-epoxypropylphenyl ether in the presence of CO₂ to give tris-chelate platina(IV)cyclopentane complexes characterized by ¹H and ¹³C NMR spectroscopy as [Pt{(CH₂)₄}(CH₂CHCH₂OPhOCO₂)(NN)], 2. The reactions proceed by the S_N2 mechanism and the rates were independent of concentration of CO₂. It is demonstrated that for 1a, the reaction proceeds 2.32 times faster than the similar reaction in which the dimethyl analog, [PtMe₂ (2,2′-bipyridine)], is used. The analog tris-chelate complex [Pt{(CH₂)₄}(CH₂CHPhOCO₂)(phen)], 3a, was similarly synthesized.