Huang Yuanshan, Zheng Xin, Wu Junyan, Gao Yong, Ling Qidan, Lin Zhenghuan
Fujian Key Laboratory of Polymer Materials, College of Chemistry and Materials Science, Fujian Normal University, Fuzhou, China.
Wuyi University, Nanping, China.
Nat Commun. 2024 Aug 2;15(1):6514. doi: 10.1038/s41467-024-50943-4.
Organic molecules with dynamic covalent-bonding characteristics have attracted much attention for their important role in constructing stimulus-responsive smart materials. However, it is difficult to realize sensitive and reversible covalent bond cleavage/formation through external stimuli in the aggregated state of molecules. Herein, a series of 2,3-diphenylmaleonitriles (DPMNs) with photoinduced π-bond cleavage properties have been designed and synthesized to construct the dynamic covalent bond materials. The cis-form 2,3-diphenylmaleonitriles (Z-DPMNs) exhibit significant photochromism in both solid and solution states under ultraviolet light and visible light. The photochromism stems from the photoinduced π-bond splitting of Z-DPMNs, resulting in a transition from the closed-shell to open-shell structure. Moreover, the twisted structure and molecular stacking of Z-DPMNs, the push-pull electron effect of substituents, and the external factors including temperature and solvent polarity have important effects on the dynamic conversion of π-bonds. Based on the sensitive and reversible optical performance transformation, Z-DPMNs can be applied as safety ink in anti-counterfeiting, information encryption and storage systems. This work not only provides an approach for constructing dynamic covalent bonds but also greatly enriches stimulus-responsive materials.
具有动态共价键特性的有机分子因其在构建刺激响应智能材料中的重要作用而备受关注。然而，在分子聚集状态下，通过外部刺激实现敏感且可逆的共价键断裂/形成是困难的。在此，设计并合成了一系列具有光致π键断裂性质的2,3-二苯基马来腈（DPMN），以构建动态共价键材料。顺式2,3-二苯基马来腈（Z-DPMN）在紫外光和可见光下的固态和溶液态中均表现出显著的光致变色现象。这种光致变色源于Z-DPMN的光致π键分裂，导致从闭壳结构向开壳结构的转变。此外，Z-DPMN的扭曲结构和分子堆积、取代基的推拉电子效应以及包括温度和溶剂极性在内的外部因素对π键的动态转换有重要影响。基于敏感且可逆的光学性能转变，Z-DPMN可作为防伪、信息加密和存储系统中的安全墨水。这项工作不仅为构建动态共价键提供了一种方法，还极大地丰富了刺激响应材料。
