Tuning nonlinear optical properties by diradical and charge transfer characters of Chichibabin’s hydrocar-bon derivatives
Tuning nonlinear optical properties by diradical and charge transfer characters of Chichibabin’s hydrocar-bon derivatives
复制标题
通过奇奇巴宾烃衍生物的双自由基和电荷转移特性调节非线性光学性质
DOI：
10.1002/cphc.201601226
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发表时间：
2017
期刊：
影响因子：
2.9
通讯作者：
M. Nakano
中科院分区：
文献类型：
--
作者：
K. Fukuda;Y. Suzuki;H. Matsui;T. Nagami;Y. Kitagawa;B. Champagne;K. Kamada;Y. Yamamoto;M. Nakano
从理论上探讨了奇奇巴宾类化合物的杂原子衍生物，以突出其电子结构与非线性光学性质之间的关系。结果表明，系统分为两类：一类是在两个主要共振结构之间具有中间电子结构的系统，另一类是只有一个共振结构近似的电子结构。研究发现，前一类衍生物的静态二阶超极化率（γ）比后一类衍生物的静态二阶超极化率（γ）大约一阶，这是因为它们具有中间双自由基或电荷转移（CT）特性。利用静电场模型对非对称体系进行了进一步的研究，结果表明中间CT特性是导致非对称体系中γ的大幅增强的关键。这些结果不仅阐明了具有氧化还原开关特性的开壳单线态NLO化合物的结构-性质关系，而且揭示了通过将中间CT性质引入开壳单线态体系而产生的一类新的未开发的闭壳NLO体系。
Heteroatomic derivatives of Chichibabin's hydrocarbon are explored theoretically to highlight the relationship between the electronic structure and nonlinear optical (NLO) properties. The results show that the systems are divided into two classes: one that has intermediate electronic structure between two main contributing resonance structures, and a second with an electronic structure that is approximated by only one resonance structure. It is found that the former class of derivatives exhibits approximately one‐order larger static second hyperpolarizability (γ) than the latter class, because of either their intermediate diradical or charge‐transfer (CT) characteristics. The asymmetric systems are further scrutinized by using the static electric field model, which shows that the intermediate CT character is essential for the very large enhancement ofγin the asymmetric systems. These results not only clarify the structure–property relationships of open‐shell singlet NLO compounds with redox switching properties, but also shed light on a new and unexplored class of closed‐shell NLO systems generated by the introduction of intermediate CT nature into open‐shell singlet systems.