Salomón Fernando F, Abate Pedro O, Baraldo Luis M
Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina.
CONICET - Universidad de Buenos Aires. Instituto de Química-Física de Materiales, Ambientes y Energía (INQUIMAE), Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina.
Dalton Trans. 2024 Sep 18;53(36):15083-15092. doi: 10.1039/d4dt01848f.
Chromophore-catalyst assemblies are interesting benchmark molecules for photocatalysis. We have prepared two examples of these assemblies and characterized their behaviour as catalysts for the water oxidation reaction. In the bimetallic complexes Ru(tpy)(4,4'-X-bpy)(μ-CN)Ru(bda)(DMSO) (X = -H (1), -OCH (2), tpy = 2,2':6',2''-terpyridine, bpy = 2,2'-bipyridine, Hbda = 2,2'-bipyridine-6,6'-dicarboxylic acid and DMSO = (CH)SO), a Ru(II)-polypiridine chromophore {Ru(tpy)(4,4'-X-bpy)} is linked by a cyanide bridge to a {Ru(bda)} water oxidation catalyst. Both complexes catalyze water oxidation both chemically, using Ce(IV) as the terminal oxidant, and electrochemically. Electrochemical and spectroelectrochemical studies, aided with (TD)DFT calculations, allowed us to study the different species involved in the catalytic cycle. For the , an intense MMCT (metal-to-metal charge transfer) band suggests a geometrical reorganization during the oxidation process. The wave associated with oxidation to the species shows an increased current that suggests that it may be a catalyst for the water oxidation reaction. Further oxidation results in the redox state which is an active catalyst for the water oxidation reaction as demonstrated by the evolution of oxygen.
发色团 - 催化剂组装体是光催化领域有趣的基准分子。我们制备了这类组装体的两个实例，并对它们作为水氧化反应催化剂的行为进行了表征。在双金属配合物Ru(tpy)(4,4'-X-bpy)(μ-CN)Ru(bda)(DMSO)（X = -H (1)，-OCH (2)，tpy = 2,2':6',2''-三联吡啶，bpy = 2,2'-联吡啶，Hbda = 2,2'-联吡啶 - 6,6'-二羧酸，DMSO = (CH)SO）中，一个Ru(II)-多吡啶发色团{Ru(tpy)(4,4'-X-bpy)}通过氰基桥连接到一个{Ru(bda)}水氧化催化剂上。这两种配合物都能使用Ce(IV)作为终端氧化剂进行化学水氧化反应，也能进行电化学水氧化反应。借助（TD）DFT计算的电化学和光谱电化学研究，使我们能够研究催化循环中涉及的不同物种。对于 ，一个强烈的MMCT（金属到金属电荷转移）带表明在氧化过程中发生了几何重组。与氧化为 物种相关的波显示电流增加，这表明它可能是水氧化反应的催化剂。进一步氧化会导致 氧化还原态，如氧气的析出所示，它是水氧化反应的活性催化剂。
