祝贺赵子建同学的文章“Nature-Inspired Photocatalytic Azo Bond Cleavage with Red Light”在线发表于
Journal of the American Chemical Society（JACS），并被选为封面文章（Cover Paper）
工作简介：
哺乳动物细胞中光氧化还原催化的新兴领域能够对大量生物过程进行时空调节。然而，低能可见光驱动的稳定共价键的选择性断裂仍然是一个巨大的挑战。在此，我们报道了市售染料（缩写为NMB+）的红光激发会导致水溶液和缺氧细胞中稳定偶氮键的催化裂解，因此是一种光递送药物或功能分子的方法。详细的机理研究表明，偶氮键断裂是由以前未知的连续双光子过程触发的。第一个光子产生三重激发态 3NMB+*，其被电子供体还原猝灭以产生质子化的NMBH•+。NMBH•+发生歧化反应，生成初始NMB+和二电子还原的NMBH（即无色NMB，缩写为LNMB）。有趣的是，LNMB与所有四种偶氮底物形成电荷转移复合物，在红色区域具有强吸收带。第二个红色光子诱导电子从LNMB转移到偶氮基板，导致偶氮键断裂。本文报道的电荷转移复合物介导的双光子催化机制让人想起黄素依赖性天然光酶，其利用高能光子催化键断裂反应。红光驱动的光催化策略为生物正交偶氮键断裂提供了一种新的方法，用于药物或功能分子的光递送。
文章摘要：
The emerging field of photoredox catalysis in mammalian cells enables spatiotemporal regulation of a wealth of biological processes. However, the selective cleavage of stable covalent bonds driven by low-energy visible light remains a great challenge. Herein, we report that red light excitation of a commercially available dye, abbreviated NMB+ , leads to catalytic cleavage of stable azo bonds in both aqueous solutions and hypoxic cells and hence a means to photodeliver drugs or functional molecules. Detailed mechanistic studies reveal that azo bond cleavage is triggered by a previously unknown consecutive two-photon process. The first photon generates a triplet excited state, 3 NMB+ *, that is reductively quenched by an electron donor to generate a protonated NMBH•+ . The NMBH•+ undergoes a disproportionation reaction that yields the initial NMB+ and two-electron-reduced NMBH (i.e., leuco-NMB, abbreviated as LNMB). Interestingly, LNMB forms a charge transfer complex with all four azo substrates that possess an intense absorption band in the red region. A second red photon induces electron transfer from LNMB to the azo substrate, resulting in azo bond cleavage. The charge transfer complex mediated two-photon catalytic mechanism reported herein is reminiscent of the flavin-dependent natural photoenzyme that catalyzes bond cleavage reactions with high-energy photons. The red-light-driven photocatalytic strategy offers a new approach to bioorthogonal azo bond cleavage for photodelivery of drugs or functional molecules. Zhao,Z . et. al. J. Am. Chem. Soc. 2023
封面描述：The convergence of two beams of red light functions akin to a knife and fork set, effectively piercing and splitting the nitrogen–nitrogen double bond of azo compounds upon interaction with a photocatalyst.
原文链接：
https://www.x-mol.com/news/875131