新型烯桥二芳基乙烯光致变色体系

Photochromic Diarylethenes Based on Novel Ethene Bridges

光致变色材料在一定的波长和强度的光作用下分子结构发生开闭环等变化,从而导致其对光的吸收峰(即颜色)的相应改变,且这种改变一般是可逆的。光致变色体系在光照前后的物理、化学性能(特别是吸收、荧光性质)会发生显著变化,可广泛应用于变色眼镜、光开关、逻辑门以及信息存储等领域。在众多光致变色体系中,有机二芳基乙烯体系具有高热稳定性,一直是应用研究的热门对象。由于全氟环戊烯作为烯桥具有突出的抗疲劳度、双稳态性能,目前大多数二芳基乙烯皆基于此烯桥而设计制备。鉴于二芳基乙烯的烯桥处于光反应中心,对光致变色性能调控尤为显著,而全氟环戊烯作为烯桥在结构上惰性而难以实现化学修饰,因而近年来涌现出许多新型的桥连,实现了更好的性能和更多的应用,本文介绍具有代表性的烯桥及其对应的二芳基乙烯化合物的研究现状,并对其应用前景进行了分析及展望。

Photochromic materials exhibit light-induced color change essentially due to the reversible structure change such as ring-open to ring-closed states upon photoirradiation, resulting in the distinct difference in photoinduced chemical reactions/physical properties. These photochromic properties have attracted much attention on the applications of ophthalmic lenses, photo-switches, molecular actuators, logic gates, and information storages. Among various photochromic systems, organic diarylethenes have become increasing interest because of their high thermal stability. Particularly, the ethene bridge with perfluorocyclopentene can bring excellent fatigue resistance and bistability to the diarylethene family, thereby nowadays it is adopted for developing diarylethene derivatives. The ethene bridges have very great effects on photochromic properties since they are located exactly in the photoreaction center. Given the difficulty in structurally modifying the classic ethene bridge of perfluorocyclopentene owing to its chemical inertness, several other ethene bridges have emerged to achieve higher performance and more applications. This review covers the latest research progresses on the important ethene bridges and their corresponding diarylethene derivatives, and their application prospects.