Abstract:

Photoswitches are chromophores that undergo reversible isomerization between different states upon irradiation with light, allowing a convenient means to spatiotemporally control their influence over the system of interest. However, a significant limitation of classical photoswitches is the requirement to initiate the switching in one or both directions using deleterious UV light with high damage, energy consumption, toxicity, and poor tissue penetration. Red-shifted photoswitches are in high demand and have attracted recent research interest. In this review, we highlight recent progress towards the development of visible- and NIR-activated photoswitches characterized by distinct photoswitches and examine the key photochromic properties, including photoconversion efficiency, isomerization quantum yields, the thermal half-lives of the thermodynamically unstable isomers, and the resistance of the systems to photofatigue in each case. Finally, the opportunities and challenges that visible- and NIR-activated photoswitches may face in future development are prospected.

Key words: visible light, near-infrared light, photoswitch, photochromism

摘要：

光开关染料分子可以在光照条件下于不同状态间发生可逆异构化，为高时空分辨远程控制材料和生物系统提供了独特的机会。然而，传统的光开关染料分子不可避免地需要紫外光激发，紫外光具有高损伤、高耗能、毒性大、组织穿透力差等弊端，导致其在生物领域应用受限。可见光/近红外光低能耗、低损伤且组织穿透力强，更能满足生物应用需求。因此，开发长波长驱动的光开关染料分子对推进其在超分辨成像、光药理学等新兴交叉学科领域应用具有重要意义。本文详细总结了近年来传统和新兴光开关染料分子在红移激发波长方面取得的最新研究进展，并针对转换效率、异构化量子产率、热力学稳定性以及抗疲劳性等指标对其光开关性能进行评价与讨论。最后对可见光/近红外光开关染料分子在未来发展过程中可能面临的机遇和挑战进行了展望。

关键词: 可见光, 近红外, 光开关染料, 光致变色