Light-Driven Methyl Exchange Reactions in Square-Planar Palladium(II) and Platinum(II) Complexes

Square-planar palladium­(II) and platinum­(II) methyl complexes with terpyridine and 6,6″-diamino terpyridine ligands undergo methyl exchange reactions upon exposure to light. The half-life of the methyl exchange reactions correlates with the relative Pd–C and Pt–C bond strengths. No exchange between methyl and phenyl groups is observed, probably due to the stronger Pt–C bond in the platinum phenyl complex. A mechanism is proposed whereby a dinuclear intermediate is generated upon irradiation that has a weakened M–C bond in the excited state, resulting in the observed methyl exchange reactions