Nagasaka Tatsuhiro, Sotome Hikaru, Morikawa Soichiro, Uriarte Lucas Martinez, Sliwa Michel, Kawai Tsuyoshi, Miyasaka Hiroshi
Division of Frontier Materials Science and Center for Advanced Interdisciplinary Research, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan.
Univ. Lille, CNRS, UMR 8516, LASIR, Laboratoire de Spectrochimie Infrarouge et Raman Lille 59000 France.
RSC Adv. 2020 May 27;10(34):20038-20045. doi: 10.1039/d0ra03523h. eCollection 2020 May 26.
The electrocyclic reaction dynamics of a photochromic dithiazolylarylene derivative, 2,3-dithiazolylbenzothiophene (DTA) was investigated by using time-resolved transient absorption and fluorescence spectroscopies. The closed-ring isomer of DTA undergoes cycloreversion through the conical intersection mediating the potential energy surfaces of the excited and ground states, which is in agreement with the Woodward-Hoffmann rules for the electrocyclic reactions of 6π electron systems. On the other hand, a large portion of the open-ring isomer undergoes cyclization along the distinct reaction scheme, in which the cyclization takes place in the excited state manifold leading to the formation of the excited state of the closed-ring isomer. The suppression of the geometrical motion of DTA due to the intramolecular interaction could open a new efficient reaction pathway resulting in the formation of the electronically excited state of the product.
通过时间分辨瞬态吸收光谱和荧光光谱研究了光致变色二噻唑基亚芳基衍生物2,3-二噻唑基苯并噻吩（DTA）的电环化反应动力学。DTA的闭环异构体通过介导激发态和基态势能面的锥形交叉进行环化逆转，这与6π电子体系电环化反应的伍德沃德-霍夫曼规则一致。另一方面，大部分开环异构体沿着不同的反应路径进行环化，其中环化发生在激发态流形中，导致形成闭环异构体的激发态。由于分子内相互作用对DTA几何运动的抑制可能会开辟一条新的有效反应途径，从而导致产物电子激发态的形成。
