Synthesis and Characterization of Palladium(II) and Platinum(II) Adducts and Cyclometalated Complexes of 6,6′-Dimethoxy-2,2′-bipyridine: C(sp³)–H and C(sp²)–H Bond Activations

Reactions of 6,6′-dimethoxy-2,2′-bipyridine (bipy^2OMe) with palladium­(II) and platinum­(II) chlorides or acetates afforded either neutral, [M­(bipy^2OMe)­Cl₂], and cationic, [Pt­(bipy^2OMe)₂]­[Pt­(DMSO)­Cl₃]₂, adducts or cyclometalated derivatives [M­(bipy^OMe,OCH2)­X] and [M­(bipy^2OMe-H)­X]₂ (M = Pd, X = OAc, Cl; M = Pt, X = Cl) arising from respectively C­(sp³)–H and C­(sp²)–H bond activation, depending on the metal precursor, solvent, and other reaction conditions. Cyclometalated complexes of the new ligand 6-hydroxy-6′-methoxy-2,2′-bipyridine (bipy^OMe,OH), arising from monodemethylation of bipy^2OMe, were also formed as coproducts under certain reaction conditions. The crystal structures of [Pt­(bipy^2OMe)₂]­[Pt­(DMSO)­Cl₃]₂ and of [Pd­(bipy^2OMe-H)­(OAc)]₂ have been solved by X-ray crystallography