The photochemistry of inverse dithienylethene switches understood.
The photochemistry of inverse dithienylethene switches understood.
复制标题
了解反二噻吩乙烯开关的光化学。
DOI：
10.1039/c4cp03641g
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
M. Takeshita
中科院分区：
文献类型：
--
作者：
S. Aloïse;R. Yibin;I. Hamdi;G. Buntinx;A. Perrier;F. Maurel;D. Jacquemin;M. Takeshita
通过稳态、超快光谱和最先进的含时密度泛函理论计算，研究了一系列二噻吩基乙烯（自由或被烷基桥封闭在理想的光活性构象中）的光物理性质。由于明确的超快瞬态签名确证NMR结果，我们带来了强有力的证据表明，非反应性的平行开放式构象已被有效地删除的链。第一次，该物种的光物理学，即120 ps的内部转换是突出的。与文献中的主要思想相矛盾的是，光环化机制被合理化为直接光环化机制，该直接光环化机制从弗兰克-康登区域直接通过一个圆锥形交叉点，在100 fs（不是几皮秒）内，而竞争机制通过松弛的S1状态发生。源自这种松弛状态的松弛过程（荧光和内部转换）对封闭链的长度敏感。这两个伴随的途径是必要的合理化：（i）发射和环化量子产率之间的反比关系和（ii）后者的非统一值的桥接化合物。
The photophysical properties of a series of dithienylethenes, free or blocked in an ideal photoactive conformation by an alkyl bridge, have been investigated by stationary, ultrafast spectroscopy and state-of-the-art time-dependent density functional theory calculations. Thanks to the clear ultrafast transient signatures corroborating NMR results, we bring strong evidence that the unreactive parallel open form conformer has been efficiently removed by the chain. For the first time, the photophysics of this species, namely an internal conversion of 120 ps is highlighted. In contradiction to the main ideas in the literature, the photocyclization mechanism is rationalized by a direct photocyclization mechanism from the Franck-Condon region passing directly through a conical intersection within ≈100 fs (not few picoseconds) while a competitive mechanism occurs through the relaxed S1 state. Relaxation processes (fluorescence and internal conversion) originating from this relaxed state are sensitive to the length of the blocking chain. Both concomitant pathways are necessary to rationalize: (i) the inverse relationship between emission and cyclization quantum yields and (ii) the non-unity value of the latter for bridged compounds.
影响因子：
3.3
作者：
Ishibashi, Yukihide;Mukaida, Masayuki;Irie, Masahiro
通讯作者：
Irie, Masahiro
影响因子：
15
作者：
Uno, Kakishi;Niikura, Hiroyuki;Irie, Masahiro
通讯作者：
Irie, Masahiro