Arene C–H bond activation and methane formation by a methylplatinum(ii) complex: experimental and theoretical elucidation of the mechanism

Abstract

In a combined experimental/computational investigation, the behavior of neutral complex [PtMe₂(DMSO)₂], 1, has been explored in the cyclometalation reaction with HC^N ligands (HC^N = 2-(p-tolyl)pyridine (Htpy), 2-phenylpyridine (Hppy), 1-phenylpyrazole (Hppz) and benzo[h]quinoline (Hbhq)). The losses of DMSO from [PtMe₂(DMSO)₂], 1, activation of the C_sp²–H bond of HC^N and then the liberation of methane result in the formation of a cyclometalated [PtMe(C^N)(DMSO)] complex. The experimental studies complemented by DFT calculations indicate that the reaction of 1 with HC^N proceeds via HC^N coordination through the N donor atom, intramolecular oxidative addition of the arene C–H bond, and final dissociation of methane from a platinum hydride complex. The kinetic parameters for the C–H activation process are also determined.