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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

采用飞秒激光光谱、半经验分子轨道计算和电化学方法研究了二芳基乙烯衍生物、水杨醛苯胺衍生物以及偶氮苯衍生物与铑、钌配合物的光致变色和电致变色反应。还通过原子力显微镜和时间分辨荧光SNOM研究了螺吡喃衍生物在固体界面上的光致变色反应，发现SA的质子转移发生在200 〜 300 fs的时间常数下，随后发生结构变化。在室温下，速率的溶剂依赖性小得可以忽略，表明固相中的有效光致变色反应。在二芳基乙烯衍生物中，首次证实了闭环反应按照Woodward-Hoffmann规则在没有任何中间体的情况下进行。反应的活化能也被发现是可以忽略不计的小。此外，激发态Si中的大的结构变化 ...更多信息在偶氮苯衍生物中，即使在激发态到S2态的过程中，也可以通过反转机制从S1态开始发生反-顺异构化反应，时间常数为1 × 10 ps，取决于溶剂的粘度. Rh偶氮苯配合物的氧化还原行为是不可逆的，但表现出反-顺异构化，而Ru偶氮苯配合物的氧化还原行为是可逆的，但表现出超快的激发能从偶氮苯到MLCT态的转移，没有任何异构化。螺吡喃生成汞的过程中，固相界面上的分子几乎没有发生位移。而J-聚集体是通过分子在热能作用下发生100 nm ~ μm的大位移而形成的，这些结果对于开发新型光致变色材料和纳米光电响应器件具有重要意义。少