Multielectron reduction of carbon dioxide by polynuclear coordination complexes

为了开发具有二氧化碳配位空间的新型双核配合物，合成了一种以环己烷为间隔位，以联吡啶为配位的新型桥接配体。配体与单核三吡啶钌配合物的反应使得分离出双核钌配合物。双核配合物表现出由配体和钌中心形成的可逆氧化还原性质。在CO2条件下的电化学测量中，观察到催化电流。气相色谱分析证实CO是唯一可检测的气相产物。这些结果表明，柔性桥接的双核钌配合物可以作为二氧化碳还原催化剂。

In order to develop novel dinuclear complexes with coordination space for binding of carbon dioxide, a new bridging ligand, which includes a cyclohexane moiety as a spacer and two bipyridine groups as coordination sites, was synthesized. The reaction of the ligand with mononuclear ruthenium terpyridine complexes allowed the isolation of a dinuclear ruthenium complex. The dinuclear complex shows reversible redox properties originated from the ligand and ruthenium centers. In electrochemical measurements under CO2 conditions, catalytic currents was observed. Analyses by gas chromatography confirmed that CO was the only detectable gas phase product. These results show that flexibly bridged dinuclear ruthenium complexes can act as carbon dioxide reduction catalysts.