中国科学院化学研究所王铁团队报道了荧光分子C=N键断裂与重组的空间限制行为。 相关研究成果于2021年4月12日发表在国际知名学术期刊《德国应用化学》。

受限空间中的分子表现出不寻常的行为在整体系统中是不常见的。该行为可以为探索新的反应途径提供替代策略。尼罗红（NR）在溶液中的C=N键裂解是一个不可逆反应。

该文中，研究人员利用空间限制在阳离子-胶束限制系统内将该反应转化为可逆过程。NR的荧光在红绿之间移动了9个循环。基于空间限制的新化学途径可以归结为两个因素：增加反应物的局部浓度和降低反应能垒。该效应得到了实验证据和理论计算的支持。由限制室组成的交联二氧化硅壳稳定了封闭的分子。因此可以减少荧光团泄漏并在大多数环境中保持荧光强度，包括在溶液中、在纸上和在水凝胶膜中，并且扩展了在加密信息和多信息显示中的实际应用。

附：英文原文

Title: Spatial Confinement for Cleaving and Reforming C=N Bonds of Fluorescent Molecules

Author: Keyan Liu, Tie Wang

Issue&Volume: 2021-04-12

Abstract: Molecules in confined spaces exhibit unusual behaviors that are not typically observed in bulk systems. Such behavior can provide alternative strategies for exploring new reaction pathways. Cleavage of the C=N bond of Nile red (NR) in solution is an irreversible reaction. Here, we used spatial confinement within a cationic‐micelle confined system to convert this reaction to a reversible process. The fluorescence of NR shifted between red and green for nine cycles. The new chemical pathway based on spatial confinement can be attributed to two factors: increasing the local concentration of reactants and reducing the reaction energy barrier. This effect is supported by both experimental evidence and theoretical calculations. The cross‐linked silica shell comprising the confinement chamber stabilizes the enclosed molecules. This reduces fluorophore leakage and maintains fluorescence intensity in most environments, including in solution, on paper, and in hydrogel films, and expands practical applications in encrypted information and multi‐informational displays.

DOI: 10.1002/anie.202103471

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202103471