Ru(ii)–Re(i) binuclear photocatalysts connected by –CH2XCH2– (X = O S CH2) for CO2 reduction

摘要

We developed Ru(ii)–Re(i) supramolecular photocatalysts in which each metal complex unit is connected by a –CH2XCH2– (X = O, S, CH2) chain. The photocatalyst with X = O exhibited the best photocatalytic efficiency for CO2 reduction in the reported systems using a NAD(P)H model compound as an electron donor because the introduced oxygen atom strengthened the oxidation power of the >Ru photosensitizer unit in the excited state and accelerated electron transfer from the one-electron-reduced >Ru photosensitizer unit to the >Re catalyst unit. In contrast, the catalytic ability of the photocatalyst with X = S rapidly decreased during irradiation because the supramolecular structure split into mononuclear complexes. A detailed mechanism for the efficient photocatalytic reaction involving these supramolecular photocatalysts was investigated for the first time.