Concurrent B-to-Pt Methyl Migration and B-Center Retention in Aerobic Oxidation of Methylborato Platinum(II) Complexes

A new anionic methoxy methylbis(2-pyridyl)borate ligand enables facile oxidation of the derived dimethylplatinum(II) complex, 10, with O2 in methanol to produce a mixture of two platinum(IV) complexes in combined quantitative yield, one supported by a modified ligand, dimethoxybis(2-pyridyl)borate, and the second supported by the original methoxy methylbis(2-pyridyl)borate. The former product results from the aerobic PtII-to-PtIV oxidation and B-to-PtIV methyl migration with subsequent bridging of the boron and PtIV centers by a methoxy group derived from the solvent. A similar reactivity was also demonstrated for 11, the methyl methoxo platinum(II) analogue of 10. Factors responsible for the product distribution are discussed.