Synthesis and Characterization of Palladium(II) and Platinum(II) Adducts and Cyclometalated Complexes of 6,6′-Dimethoxy-2,2′- bipyridine: C(sp~3)?H and C(sp~2)?H Bond Activations

摘要

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))Cl_2], and cationic, [Pt(bipy~(2OMe))_2][Pt(DMSO)Cl_3]_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(sp~3)?H and C(sp~2)?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)Cl_3]_2 and of [Pd- (bipy~(2OMe)-H)(OAc)]_2 have been solved by X-ray crystallography.