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FEMTOSECOND SPECTROSCOPIC STUDY ON SOME PHOTOCHROMIC AND ELECTROCHROMIC REACTIONS AND THEIR RESPONSE AT THE INTERFACE

一些光致变色和电致变色反应及其界面响应的飞秒光谱研究

基本信息

批准号：
10450326
负责人：
TAMAI Naoto
金额：
$ 6.98万
依托单位：
KWANSEI GAKUIN UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Photochromic and electrochromic reactions of some diarylethene derivatives, salicylidene aniline (SA) derivatives, and Rh- and Ru-complexes conjugated with azobenzene derivatives have been investigated by femtosecond laser spectroscopy, semi-empirical molecular orbital calculation, and electrochemical methods. Photochromic reaction of a spiropyran derivative on the solid interface has been also examined by AFM and time-resolved fluorescence SNOM.It was found that the proton transfer of SA took place with a time constant of 200 〜 300 fs followed by the structural change. The solvent dependence of the rate was negligibly small at R.T.indicating the efficient photochromic reaction in the solid phase. In diarylethene derivatives, the ring closure reaction was firstly confirmed to take place without any intermediates according to the Woodward-Hoffmann rule. The activation energy of the reaction was also found to be negligibly small. In addition, the large structural change in the excited si … More nglet state reduces the quantum yield of the photochromic reaction.In azobenzene derivatives, the trans-cis isomerization was found to occur from S1 state with a time constant of 1 〜 10 ps depending on the solvent viscosity through the inversion mechanism even in the excitation to the S2 state. Rh-complexes with azobenzene show trans-cis isomerization although their redox behaviors are irreversible, whereas Ru-complexes show ultrafast excitation energy transfer from azobenzene to MLCT state without any isomerization although their redox behaviors are reversible.Photochromic response at the solid interface was examined by scanning probe microscopy. The formation of merocyanine from spiropyran was confirmed to be almost no displacement of the molecules on the solid interface. However, the J-aggregate was formed through the large displacement of a few 100 nm to μm of molecules actrivated by the thermal energy.These results are considered to be indispensable to develop new photochromic and electrochromic materials and nanosized photo- and electro-responsive devices. Less

通过飞秒激光光谱、半经验分子轨道计算和电化学方法研究了一些二芳基乙烯衍生物、水杨基苯胺(SA)衍生物以及与偶氮苯衍生物共轭的Rh-和Ru-配合物的光致变色和电致变色反应。通过AFM和时间分辨荧光SNOM检测了螺吡喃衍生物在固体界面上的光致变色反应，发现SA在200〜300 fs的时间常数内发生质子转移，随后发生结构变化。在室温下，速率对溶剂的依赖性小到可以忽略不计，表明固相中的光致变色反应有效。在二芳基乙烯衍生物中，根据伍德沃德-霍夫曼规则，首次证实在没有任何中间体的情况下发生闭环反应。还发现反应的活化能小得可以忽略不计。此外，激发态Si … More nglet态的大结构变化降低了光致变色反应的量子产率。在偶氮苯衍生物中，即使在激发到S2态时，也发现从S1态开始发生反式-顺式异构化，时间常数为1〜10 ps，具体取决于溶剂粘度，通过反转机制。 Rh-偶氮苯配合物虽然其氧化还原行为不可逆，但表现出反式-顺式异构化，而Ru-配合物显示出从偶氮苯到MLCT状态的超快激发能量转移，尽管其氧化还原行为是可逆的，但没有任何异构化。通过扫描探针显微镜检查固体界面处的光致变色响应。证实从螺吡喃形成部花青时固体界面上的分子几乎没有位移。然而，J-聚集体是通过热能激活几个100 nm至μm的分子的大位移而形成的。这些结果被认为对于开发新型光致变色和电致变色材料以及纳米级光响应和电响应器件是必不可少的。较少的