Zhou Jiachao, Xing Chang, Zhai Yali, Xu Wenjuan, Zhao Yujie, Geng Kangshuai, Hou Hongwei
College of Chemistry and Green Catalysis Center, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China.
Inorg Chem. 2021 May 17;60(10):7240-7249. doi: 10.1021/acs.inorgchem.1c00331. Epub 2021 Apr 26.
For studying the effect of a substituted group on the photoresponsive third-order nonlinear-optical (NLO) properties, photosensitive azobenzene derivative was first selected to construct metal complexes {[Zn(L1)(HO)]·2DMA)} () and {[Cd(L1)(4,4'-bpy)HO]·HO} (). Then with a substituted methyl on the azobenzene ring was used to construct complexes {[Zn(L2)(4,4'-bpy)(HO)]} () and {[Cd(L2)(4,4'-bpy)(HO)]} (). When the azobenzene moiety of the complexes is trans, the NLO behaviors of the complexes are the same. However, after the azobenzene moiety is excited by ultraviolet (UV) light to change from trans to cis, the substituted methyl increases the repulsion between two azobenzene rings in and , thereby affecting their NLO behaviors. Therefore, the nonlinearity of the two types of complexes is different after UV irradiation. Density functional theory calculations support this result. The substituted methyl has a significant influence on the nonlinear absorption behaviors of and . This work not only reports the examples of photoresponsive NLO materials based on metal complexes but also provides a new idea to deeply explore NLO properties.
为了研究取代基对光响应三阶非线性光学（NLO）性质的影响，首先选择光敏偶氮苯衍生物构建金属配合物{[Zn(L1)(H2O)]·2DMA}（）和{[Cd(L1)(4,4'-bpy)(H2O)]·H2O}（）。然后使用在偶氮苯环上带有取代甲基的构建配合物{[Zn(L2)(4,4'-bpy)(H2O)]}（）和{[Cd(L2)(4,4'-bpy)(H2O)]}（）。当配合物的偶氮苯部分为反式时，配合物的NLO行为相同。然而，在偶氮苯部分被紫外光激发从反式变为顺式后，取代甲基增加了和中两个偶氮苯环之间的排斥力，从而影响它们的NLO行为。因此，紫外光照射后这两种配合物的非线性不同。密度泛函理论计算支持这一结果。取代甲基对和的非线性吸收行为有显著影响。这项工作不仅报道了基于金属配合物的光响应NLO材料的实例，还为深入探索NLO性质提供了新思路。
