Comparison of interfacial electron transfer through carboxylate and phosphonate anchoring groups.
Comparison of interfacial electron transfer through carboxylate and phosphonate anchoring groups.
复制标题
通过羧酸盐和膦酸盐锚定基团进行界面电子转移的比较。
DOI：
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发表时间：
2007
影响因子：
2.9
通讯作者：
T. Lian
中科院分区：
文献类型：
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作者：
C. She;Jianchang Guo;S. Irle;K. Morokuma;D. L. Mohler;H. Zabri;F. Odobel;Kyoung;Fang Liu;J. Hupp;T. Lian
锚定基团对电子注入从吸附到纳米晶薄膜的影响进行了研究，通过比较注射动力学通过羧酸酯与膦酸酯基团的TiO 2和SnO 2。在第一对分子Re（LA）（CO）3Cl（ReC 1A）和Re（Lp）（CO）3Cl（ReC 1 P）中，[LA= 2，2 '-bipyridine-4，4'-bis-CH 2-COOH，Lp= 2，2 '-bipyridine-4，4'-bis-CH 2-PO 3 H2]，锚定基团通过CH 2基团与联吡啶配体绝缘。在第二对分子Ru（dcbpyH 2）2（NCS）2（RuN 3）和Ru（bpbpyH 2）2（NCS）2（RuN 3 P）中，[dcbpy= 2，2 '-联吡啶-4，4'-二羧酸，bpbpy= 2，2 '-联吡啶-4，4'-二膦酸]，锚定基团直接连接到联吡啶配体。亚皮秒红外吸收光谱测量的注入动力学表明，电子注入速率从ReC 1 P到TiO 2和SnO 2都比从ReC 1A快。从RuN 3和RuN 3 P到SnO 2膜的注入速率相似。在TiO 2上，RuN 3和RuN 3 P的注入动力学是双相的：羧酸基团提高了<100 fs组分的速率，但降低了较慢组分的速率。为了深入了解锚定基团的作用，使用密度泛函理论计算了含有羧酸酯和膦酸酯锚定基团以及有和没有CH 2间隔基的Re-bipyridine-Ti模型簇的电子结构。在CH 2间隔基的情况下，膦酸酯基团导致bpy和Ti中心之间的电子耦合比羧酸酯基团更强，这解释了ReC 1 P比ReC 1A更快的注入。当锚定基团直接连接到bpy配体而没有CH 2间隔基时，例如在RuN 3和RuN 3 P中，它们的作用是2倍：羧酸酯基团增强了bpy pi* 与TiO 2的电子耦合，并降低了bpy轨道的能量。这些竞争因素如何导致不同的效果，二氧化钛和氧化锡和不同的组成部分的两相注射动力学进行了讨论。
The effects of anchoring groups on electron injection from adsorbate to nanocrystalline thin films were investigated by comparing injection kinetics through carboxylate versus phosphonate groups to TiO2 and SnO2. In the first pair of molecules, Re(LA)(CO)3Cl (ReC1A) and Re(Lp)(CO)3Cl (ReC1P), [LA=2,2'-bipyridine-4,4'-bis-CH2-COOH, Lp=2,2'-bipyridine-4,4'-bis-CH2-PO3H2], the anchoring groups were insulated from the bipyridine ligand by a CH2 group. In the second pair of molecules, Ru(dcbpyH2)2(NCS)2 (RuN3) and Ru(bpbpyH2)2(NCS)2 (RuN3P), [dcbpy=2,2'-bipyridine-4,4'-biscarboxylic acid, bpbpy=2,2'-bipyridine-4,4'-bisphosphonic acid], the anchoring groups were directly connected to the bipyridine ligands. The injection kinetics, as measured by subpicosecond IR absorption spectroscopy, showed that electron injection rates from ReC1P to both TiO2 and SnO2 were faster than those from ReC1A. The injection rates from RuN3 and RuN3P to SnO2 films were similar. On TiO2, the injection kinetics from RuN3 and RuN3P were biphasic: carboxylate group enhances the rate of the <100 fs component, but reduces the rate of the slower components. To provide insight into the effect of the anchoring groups, the electronic structures of Re-bipyridyl-Ti model clusters containing carboxylate and phosphonate anchoring groups and with and without a CH2 spacer were computed using density functional theory. With the CH2 spacer, the phosphonate group led to a stronger electronic coupling between bpy and Ti center than the carboxylate group, which accounted for the faster injection from ReC1P than ReC1A. When the anchoring groups were directly connected to the bpy ligand without the CH2 spacer, such as in RuN3 and RuN3P, their effects were 2-fold: the carboxylate group enhanced the electronic coupling of bpy pi* with TiO2 and lowered the energy of the bpy orbital. How these competing factors led to different effects on TiO2 and SnO2 and on different components of the biphasic injection kinetics were discussed.