4,4'-Bipyridine axially coordinated binuclear cobaloxime complexes as molecular catalysts for light-driven hydrogen evolution

摘要

Reactions of [Co(dmgH)(dmgH(2))Cl-2] (dmgH = dimethylglyoxime) or [Co(chdH)(chdH(2))Cl-2] (chd = 1,2-cyclohexanedione dioximate) with 4,4'-bipyridine in MeOH in the presence of Et3N resulted in the formation of binuclear cobaloxime complexes [{Co(dmgH)(2)Cl}(2)(bipy)] (1, bipy = 4,4'-bipyridine) and [{Co(chdH)(2)Cl}(2)(bipy)] (2) in good yields. Complexes 1 and 2 were characterized by NMR and X-ray crystallography. Both 1 and 2 were found to be molecular catalysts for light-driven hydrogen evolution in the presence of Eosin Y as photosensitizer and triethanolamine as sacrificial electron donor in aqueous acetonitrile solutions upon irradiation.