文献类型：期刊文献

英文题名：Photolysis of fungicide triadimefon: A combined experimental and theoretical investigation on homolytic C[sbnd]O and C[sbnd]N bonds dissociation mechanisms

作者：Ni, Zhigang[1]; Chen, Zhi[2]; Zhang, Xuewei[2]; Yang, Xuerui[2,3]; Zhou, Lei[2,3]

机构：[1] College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University, Hangzhou, 311121, China; [2] State Environmental Protection Key Lab of Environmental Risk Assessment and Control on Chemical Processes, School of Resources & Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; [3] Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China

年份：2023

卷号：436

外文期刊名：Journal of Photochemistry and Photobiology A: Chemistry

收录：EI(收录号：20240815593087)

语种：英文

外文关键词：Density functional theory - Dissociation - Energy barriers - Fungicides - Mass spectrometry - Potential energy - Quantum chemistry - Rate constants

摘要：Among the most frequently used fungicides, triazole has been widely applied in agriculture on many crops. Extensive usage and low effective utilization result in the widespread occurrence of this kind of chemicals in the environment. Known as an important decomposition pathway in aquatic environment, photochemical transformation is believed to significantly affect the fate of organic contaminants. Herein, we reported the detailed photodegradation mechanism of a typical triazole, triadimefon (TDF), based on a combined experimental and theoretical strategy. Our results reveled that TDF could undergo a relative fast photodegradation with a pseudo-first-order rate constant of 0.14 h?1. Photoproducts identification using high-resolution mass spectrometry (HRMS) analyses indicated two different photolysis pathways of TDF, namely, the homolytic C[sbnd]O and C[sbnd]N bonds dissociation processes. Density functional theory (DFT) and time-dependent DFT (TDDFT) methods were employed to explore these two processes. Theoretical results showed that the C[sbnd]O bond dissociation could occur in either the S1 or T1 state, with the energy barrier being 9.0 and 10.7 kcal/mol, respectively, while the C[sbnd]N bond dissociation was only possible to occur in the T1 state, with a higher energy barrier of 24.3 kcal/mol. In addition, spin-orbit coupling calculations indicated that the triplet state could be effectively populated through S1 → T3 intersystem crossing. The present study highlighted the potential application of DFT and TDDFT methods as stable methods in photochemical study. ? 2022 Elsevier B.V.