Insights into the Photo-induced Isomerization Mechanisms of a N,C-Chelate Organoboron Compound : a Theoretical Study.

CHEMPHYSCHEM(2020)

引用 13|浏览7
暂无评分
摘要
As the first discovered organoboron compound with photochromic property, B(ppy)Mes(2) (ppy=2-phenylpyridine, Mes=mesityl) displays rich photochemistry that constitutes a solid foundation for wide applications in optoelectronic fields. In this work, we investigated the B(ppy)Mes(2) to borirane isomerization mechanisms in the three lowest electronic states (S-0, S-1, and T-1) based on the complete active space self-consistent field (CASSCF) and its second-order perturbation (CASPT2) methods combined with time-dependent density functional theory (TD-DFT) calculations. Our results show that the photoisomerization in the S-1 state is dominant, which is initiated by the cleavage of the B-C-ppy bond. After overcoming a barrier of 0.5 eV, the reaction pathway leads to a conical intersection between the S-1 and S-0 states (S-1/S-0)(x), from which the decay path may go back to the reactant B(ppy)Mes(2) via a closed-shell intermediate (Int1-S-0) or to the product borirane via a biradical intermediate (Int2-S-0). Although triplet states are probably involved in the photoinduced process, the possibility of the photoisomerization in T-1 state is very small owing to the weakly allowed S-1 -> T-1 intersystem crossing and the high energy barrier (0.77 eV). In addition, we found the photoisomerization is thermally reversible, which is consistent with the experimental observations.
更多
查看译文
关键词
excited states,organoboron compounds,photochemistry,photochromism,quantum chemical calculations
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要