Photoconversion of a redox-active self-assembled monolayer: in situ probing of photoinduced CO dissociation from a triruthenium cluster center on gold.
Photoconversion of a redox-active self-assembled monolayer: in situ probing of photoinduced CO dissociation from a triruthenium cluster center on gold.
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DOI：
10.1002/anie.200460651
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发表时间：
2005-01
影响因子：
--
通讯作者：
M. Abe;T. Masuda;T. Kondo;K. Uosaki;Y. Sasaki
中科院分区：
文献类型：
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作者：
M. Abe;T. Masuda;T. Kondo;K. Uosaki;Y. Sasaki
组装在固体表面或固/液界面的分子化合物的光反应性的研究是功能分子薄膜的光化学设计的先决条件。[1]通过使用有机、无机和生物构建块在电极表面上制造光响应分子层已经进行了广泛的研究，其中观察到例如异构化、[2]化学键形成和裂解[3]和定向电子转移。[4]光诱导配体取代是一个额外的潜在候选人，用于控制薄膜的表面性质，从过渡金属配位化合物构建。虽然溶液相光诱导取代反应已经取得了重大进展，[5]但迄今为止，它们在固体表面精确调节薄膜性质的应用很少被开发。[6]在这里，我们描述了在原位观察和分析的光诱导CO解离从自组装单层（SAM）的三钌簇在Au（111），这是，据我们所知，第一个明确定义的例子，清洁的光转化的氧化还原活性SAM，导致一个显着的移动的氧化还原电位。我们还报道了本SAM的光电流产生，这是这类簇分子的一个前所未有的发现。因此，这项研究为电极表面氧化还原活性分子膜的光化学设计提供了一条新途径，这在分子电子学和器件中应该有相当大的用途。方案1示出了SAM中提出的光化学反应。我们采用二硫化物官能化的，CO-连接的三钌簇1作为光响应分子。[7]选择该化合物是因为其在溶液中的明确的光诱导CO解离[8]以及在金电极表面上制备密集堆积的SAM的方法的可用性。[7]这种类型的三核簇[9]已被用于通过化学合成[10-14]和在金表面上的逐层沉积[15]来构建配体桥接的扩展分子结构，以及制造配体开关器件。[16]配合物1是混合价的
Investigations on the photoreactivity of molecular compounds assembled on solid surfaces or at solid/solution interfaces are a prerequisite for the photochemical design of functional molecular thin films.[1] Extensive studies have been made on the fabrication of photoresponsive molecular layers on electrode surfaces by using organic, inorganic, and biological building blocks, in which, for example, isomerization,[2] chemical bond formation and cleavage,[3] and directional electron transfer are observed.[4] Photoinduced ligand substitution is an additional potential candidate for controlling surface properties of thin films that are constructed from transition-metal coordination compounds. Although significant progress has been made in solution-phase photoinduced substitution reactions,[5] their application to precise tuning of thin-film properties at solid surfaces have rarely been exploited to date.[6] Here we describe the in situ observation and analysis of photoinduced CO dissociation from a self-assembled monolayer (SAM) of a triruthenium cluster on Au (111), which is, to our knowledge, the first well-defined example of clean photoconversion of a redox-active SAM that leads to a significant shift of the redox potential. We also report on photocurrent generation by the present SAM, which is an unprecedented finding for this class of cluster molecules. This study thus provides a new route to photochemical design of redox-active molecular films on electrode surfaces, which should be of considerable use in molecular electronics and devices. Scheme 1 illustrates the proposed photochemical reaction in the SAM. We employed disulfide-functionalized, CO-ligated triruthenium cluster 1 as photoresponsive molecule.[7] This compound was chosen because of its well-defined photoinduced CO dissociation in solution [8] and the availability of a methodology for preparing densely packed SAMs on the surface of a gold electrode.[7] Trinuclear clusters of this type [9] have been used to construct ligand-bridged extended molecular architectures by chemical synthesis [10–14] and layerby-layer deposition on gold surfaces,[15] as well as to fabricate a ligand switching device.[16] Complex 1 is a mixed-valent