Supramolecular photocatalysts, which consist of redox photosensitizer and catalyst units, have recently attracted attention in the field of artificial photosynthesis. Aiming to construct a durable supramolecular photocatalyst for CO2 reduction, a new Re–Ru–Re trinuclear complex was successfully developed, where one Ru unit, acting as photosensitizer, was linked to two Re units, acting as catalysts, through ethylene chains. The novel complex was synthesized by creating two chelate moieties on the ligand of a Ru complex using the Negishi-coupling reaction, which were then coordinated to Re complexes. This trinuclear complex selectively photocatalyzed the reduction of CO2 to CO under visible light irradiation, with high durability compared with the corresponding Ru–Re binuclear complex and a mixed system of model mononuclear complexes. Absorption spectra and mass spectroscopic data of the reaction solutions revealed a rapid consumption of the electrons on the one-electron reduced species of the Ru unit, which led to suppression of the Ru unit decomposition, thereby maintaining its photosensitizing ability and product selectivity.
超分子光催化剂由氧化还原光敏剂和催化单元组成,在人工光合作用领域近期受到了关注。为了构建用于
CO2还原的长效超分子光催化剂,成功开发了一种新型Re–Ru–Re三核络合物,其中一个作为光敏剂的Ru单元通过
乙烯链连接到两个作为催化剂的Re单元。这一新颖的络合物通过Negishi偶联反应在Ru络合物的
配体上创建了两个螯合基团,随后与Re络合物结合而合成。该三核络合物在可见光照射下选择性光催化 还原为CO,相比于相应的Ru–Re双核络合物和单核络合物模型混合体系,具有更高的耐久性。反应溶液的吸收光谱和质谱数据显示,Ru单元的一电子还原物种上的电子迅速消耗,导致Ru单元的分解受到抑制,从而维持了其光敏化能力和产品选择性。