有机激发三重态参与的光化学反应研究进展

A review on photochemical reaction via organic triplet excited state

光化学反应包括直接光解和间接氧化反应,其中间接氧化反应主要通过活性氧化性物种(reactive oxygen species, ROS)包括单线态氧(1O2)、过氧自由基(O2^-)和羟基自由基(·OH)等进行。近年来,有机激发三重态(3C^*)作为一种特殊的氧化剂参与光化学反应引起了广泛关注。本文主要综述了有机三重态光敏剂的形成和光化学反应机制、3C^*参与的环境光化学反应、3C^*自由基寿命、反应速率及稳态浓度测定和激发三重态的应用5个方面,并对未来有机分子激发三重态的研究方向进行了展望,指出3C^*是很多挥发性有机化合物(VOCs)或半/中等挥发性有机化合物(S/IVOCs)在大气中重要的汇,自然水体中溶解性有机质(dissolved organic matter,DOM)的激发三重态(3DOM^*)是污染物降解的主要氧化剂。今后应扩大3C^*与有机物反应的研究范畴,测定不同体系中3C^*的稳态浓度、产生速率(量子产率)等,为污染物治理提供理论依据。

Photochemical reactions include direct photolysis and indirect oxidation,in which the indirect oxidation is mainly triggered by reactive oxygen species(ROS),including singlet oxygen(1O2),superoxide(O2^-) and hydroxyl radical(·OH).In recent years,organic triplet excited state(generally refer to as 3C^*),as a special oxidant,has attracted extensive attention in photochemical reactions.In this paper,the formation and photochemical reaction mechanism of organic triplet photosensitizers,the environmental photochemical reactions in which 3C^* participates,the lifetime of 3C^*,the determination of reaction rate and steady concentration,as well as the application of triplet excited states were reviewed.Meanwhile,the research direction of triplet excited states of organic molecules in the future is prospected.It was pointed out that 3C^* was an important sink of VOCS and semi-/intermediate VOCs(S/IVOCs)in the atmosphere.The triplet states of dissolved organic matter(3DOM^*) in natural water was the main oxidant for pollutant degradation.In the future,the research scope of the reaction of 3C^* with organic matter and the determination of steady concentration and production rate(quantum yield) of 3C^* in different systems should be extended in order to provide theoretical basis for pollutant treatment.