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研究论文

基于n→π*相互作用调控偶氮苯光开关顺式异构体的热稳定性

石可添a,b, 韦相宇a,b, 海宇*,a,b, 刘丽娟a,b, 占田广a,b, 章康达*,a,b   

  1. a先进催化材料教育部重点实验室,化学与材料科学学院,浙江师范大学 金华 321004;
    b全省先进催化与吸附材料重点实验室,化学与材料科学学院,浙江师范大学 金华 321004
  • 收稿日期:2026-04-29 修回日期:2026-06-26
  • 基金资助:
    国家自然科学基金(No. 22271255)和浙江省自然科学基金(Nos. LR22B020001, LQ24B020007)资助项目.

Modulating the Thermal Stability of cis Isomers of Azobenzene Photoswitches via n→π* Interactions

Ke-Tian Shia,b, Xiang-Yu Weia,b, Yu Haia,b,*, Li-Juan Liua,b, Tian-Guang Zhana,b, Kang-Da Zhanga,b,*   

  1. aKey Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, Jinhua, 321004;
    bZhejiang Key Laboratory of Advanced Catalysis and Adsorption Materials, College of Chemistry and Materials Science, Zhejiang Normal University, Jinhua, 321004
  • Received:2026-04-29 Revised:2026-06-26
  • Contact: *E-mail: haiyuyu@zjnu.edu.cn; Kangda.Zhang@zjnu.cn
  • Supported by:
    National Natural Science Foundation of China (No. 22271255) and the Natural Science Foundation of Zhejiang Province (Nos. LR22B020001, LQ24B020007).

偶氮苯是一类在能量存储、超分子组装、生物医学等领域具有广泛应用的光开关分子,然而,其顺式异构体热稳定性往往难以在不影响吸收波长、异构化效率等关键性质的前提下实现有效调控。针对这一挑战,本研究提出了一种基于n→π*弱相互作用调控偶氮苯顺式异构体热稳定性的新策略,设计合成了一类苯环间位分别引入甲氧基和不同类型羰基的偶氮苯衍生物,通过其顺反异构化可以改变甲氧基n电子与羰基π*轨道之间的弱相互作用,进而实现调控顺式异构体的热弛豫半衰期。UV-Vis、1H-NMR实验研究表明,这类光开关分子在365 nm紫外光和430 nm可见光照射下可进行EZ光异构化,FT-IR实验证实其顺式异构体中存在明显的n→π*相互作用,并且减弱羰基的电子云密度或者增加溶剂极性有利于增强该作用,进而提高顺式异构体的热稳定性。这些研究结果为设计具有可调控热稳定性的偶氮苯光开关提供了新思路。

关键词: 光开关, 偶氮苯, n→π*弱相互作用, 热稳定性

Azobenzenes are a class of important molecular photoswitches with wide-ranging applications in energy storage, supramolecular assembly, biomedicine and beyond. However, it remains a significant challenge to effectively tune the thermal stability of their cis-isomers without compromising the key photoswitching properties such as absorption wavelength and isomerization efficiency. In this research, we deccribe a unique n→π* interaction based noncovalent strategy for tuning the cis-isomer’s thermal stability of azobenzene photoswitches, for which a series of azo molecules were designed and synthesized by introducing a methoxy group (providing n electron) and different carbonyl units (providing π* orbital) at the meta positions of azo double bond, respectively. The UV-Vis and 1H NMR experiments revealed these photoswitches could undergo reversible EZ photoisomerization upon 365 nm UV and 430 nm visible light irradiation. The FT-IR spectra verified the existence of n→π* interactions in the cis-isomers, which could be enhanced by reducing the electron-withdrawing nature of the carbonyl units or increasing the solvent polarity, thereby improving the thermal stability of the photoswitches. These findings provide new insights for the design of new molecular photoswitches with tunable thermal stability.

Key words: photoswitches, azobenzene, n→π* interaction, thermal stability.