Multielectron reduction of carbon dioxide by polynuclear coordination complexes

为了开发具有与二氧化碳结合的配位空间的新型双核配合物，合成了一种新型桥联配体，该配体以环己烷为间隔基，两个联吡啶为配位基团。通过该配体与单核Ru-三吡啶配合物的反应，可以分离出一个双核Ru-配合物。双核配合物表现出源于配体和Ru中心的可逆氧化还原性质。在CO2条件下的电化学测试中，观察到了催化电流。气相色谱分析证实，CO是唯一可检测到的气相产物。这些结果表明，柔性桥联的双核Ru络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.