Theoretical Division, Los Alamos National Laboratory, MS-B268, Los Alamos, New Mexico 87545, USA.
Inorg Chem. 2010 Mar 15;49(6):2975-82. doi: 10.1021/ic902504y.
Spatial localization of excited-state electrons in transition-metal complexes used as photocatalysts or dye sensitizers in solar cells is important for efficient electron injection into the metal oxide nanoparticles. We use density functional theory to investigate the excited states in a prototype catalyst-chromophore assembly (bpy)(H(2)O)Ru(tpy-tpy)Ru(tpy) (Ru(tpy)(bpy)(H(2)O) = catalyst, Ru(tpy)(2) = chromophore, tpy = 2,2':6',2''-terpyridine, and bpy = 2,2'-bipyridine) and a series of related compounds. We explore several bridging ligand and terminal tpy ligand modifications of the prototype assembly, with the aim of inducing electronic excitations into the terminal tpy ligand upon irradiation with visible light. The excitations into the terminal ligand (i.e., ligand covalently attached to the semiconductor in the photocatalytic synthetic cell) should, in turn, enhance electron injection into the semiconductor. Our results suggest that both introduction of a spacer group (such as phenylene or alkane) into the tpy-tpy bridge and replacement of the terminal tpy group by a more extended pi-conjugated ligand are necessary to shift the electronic excitations from the bridging ligand into the terminal ligand. These results have implications for the design of photocatalysts and dye-sensitizer assemblies based on ruthenium(II) terpyridine compounds.
在太阳能电池中作为光催化剂或染料敏化剂的过渡金属配合物中，激发态电子的空间定位对于将电子有效地注入金属氧化物纳米粒子中非常重要。我们使用密度泛函理论研究了原型催化剂-发色团组装体(bpy)(H(2)O)Ru(tpy-tpy)Ru(tpy) (Ru(tpy)(bpy)(H(2)O) = 催化剂，Ru(tpy)(2) = 发色团，tpy = 2,2':6',2''-三联吡啶，bpy = 2,2'-联吡啶)和一系列相关化合物中的激发态。我们探索了原型组装体的几种桥联配体和末端 tpy 配体修饰，目的是在可见光照射下诱导末端 tpy 配体中的电子激发。末端配体（即在光催化合成电池中与半导体共价连接的配体）中的激发应该会反过来增强电子注入半导体。我们的结果表明，在 tpy-tpy 桥中引入间隔基团（如亚苯基或链烷烃）以及用更扩展的π共轭配体取代末端 tpy 基团对于将电子激发从桥联配体转移到末端配体都是必要的。这些结果对于基于钌(II)三联吡啶化合物的光催化剂和染料敏化剂组装体的设计具有重要意义。
