One- and multi-photon cycloreversion reaction dynamics of diarylethene derivative with asymmetrical structure, as revealed by ultrafast laser spectroscopy
One- and multi-photon cycloreversion reaction dynamics of diarylethene derivative with asymmetrical structure, as revealed by ultrafast laser spectroscopy
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DOI：
10.1039/b818591c
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发表时间：
2009-04-21
影响因子：
3.3
通讯作者：
Irie, Masahiro
中科院分区：
文献类型：
--
作者：
Ishibashi, Yukihide;Mukaida, Masayuki;Irie, Masahiro
利用皮秒和飞秒激光光谱技术研究了具有不对称结构的光致变色二芳基乙烯衍生物1-（2-甲基-3-苯并噻吩基）-2-（2，4-二甲基-5-苯基-3-噻吩基）全氟环戊烯在正己烷溶液中的环化反转反应.飞秒激光光谱研究表明，闭合态的激发态（SI）寿命为1.3ps，在与内转换竞争的情况下发生了环化反转反应，反应的表观产率与激发强度无关。另一方面，皮秒激光激发A532运行导致通过经由S1状态的连续双光子吸收过程的环化反转反应产率的急剧增强，从而导致具有0.60 +/-0.1的大的环化反转产率的高激发态。对于多光子增强的环化反应，我们报道了具有C-2 v对称性的二芳基乙烯衍生物的有效环化反应可以通过分步可见双光子激发发生，但不发生通过UV单光子吸收到更高的激发态。在本发明的不对称体系中，紫外单光子和可见双光子吸收都开启了高效的环化逆转反应。本文从光学跃迁的选择规律及其与分子结构的关系出发，讨论了对称结构和不对称结构的二芳基乙烯衍生物在高激发态反应曲线的异同。
A cycloreversion reaction of a photochromic diarylethene derivative, 1-(2-methyl-3-benzothienyl)-2-(2,4-dimethyl-5-phenyl-3-thienyl)perfluorocyclopentene, with asymmetrical structure, in n-hexane solution, was investigated by means of picosecond and femtosecond laser spectroscopic methods. Femtosecond laser Spectroscopy revealed that the excited State (SI) of the closed form with a lifetime of 1,3 ps undergoies the cycloreversion reaction in competition with the internal conversion and the apparent reaction yield was independent of the excitation intensity. On the other hand, picosecond laser excitation A 532 run led to the drastic enhancement of the cycloreversion reaction yield by a successive two-photon absorption process via the S, state, leading, to hi-her excited states with a large cycloreversion yield of 0.60 +/- 0.1. For the multiphoton-enhanced cycloreversion reaction, we reported that the efficient cycloreversion reaction of a diarylethene derivative with C-2v symmetry could occur by stepwise, visible two-photon excitation but did not take place by UV one-photon absorption to a higher excited State. Ill the present asymmetrical system, both UV one-photon land visible two-photon absorption opened the efficient cycloreversion reaction. Similarities and differences of the reaction profiles ill higher excited states between diarylethene derivatives with symmetrical and asymmetrical structures are discussed front the viewpoint of the selection rule of optical transition id its dependence oil molecular structures.