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Indexed by:期刊论文

Date of Publication:2012-06-01

Journal:CHEMOSPHERE

Included Journals:SCIE、EI、PubMed

Volume:88

Issue:1

Page Number:33-38

ISSN No.:0045-6535

Key Words:Polybrominated diphenyl ethers; Excited state; TDDFT; Photochemical degradation; Photoreactivity

Abstract:This study presents new insight into the photochemical degradation of polybrominated diphenyl ethers (PBDEs), and it provides details about the structures and properties of 27 PBDE congeners in the electronically excited state using the time-dependent density functional theory method. Each PBDE congener exhibited remarkably different geometries in the ground state and the excited state. The significant lengthening of C-Br bond in each PBDE congener was observed in the excited state for the first time by theoretical calculation, which is directly involved in the photochemistry reductive debromination of n-BDE to (n-1)-BDE. Generally, the lengthening of C-Br bonds cannot occur at the para position. Furthermore, the calculated results demonstrated that the photoreactivity of PBDEs increased with an increase of bromination degree. It was also found that the pattern of Br substituents had an effect upon the photoreactivity of PBDEs. These findings suggest that the information obtained in the excited state is crucial to the mechanism explanation of the photochemical degradation of PBDEs. (C) 2012 Elsevier Ltd. All rights reserved.