Xie Qing, Chen Jingwen, Shao Jianping, Chen Chang'er, Zhao Hongxia, Hao Ce
Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), Department of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, PR China.
Chemosphere. 2009 Sep;76(11):1486-90. doi: 10.1016/j.chemosphere.2009.06.054. Epub 2009 Aug 5.
Photolysis of deca-bromodiphenyl ether (BDE-209) was investigated in tetrahydrofuran, dichloromethane, isopropanol, acetone, ethanol, methanol, acetonitrile and dimethylsulfoxide. Noticeable differences of the photolytic rates and quantum yields were found in the diverse solvents. Different to the previous deductions, hydrogen donating efficiency and electron donating efficiency of solvents were not the decisive factors for the photolytic rate in this study, which was proved by the fast photolysis of BDE-209 in CCl(4), a solvent without hydrogen and difficult to donate electrons. Besides hydrogen addition process, intermolecular polymerization might occur during the photolysis. Density functional theory (DFT) calculation was performed to understand the molecular properties of BDE-209 in different solvents. The lowest singlet vertical excitation energy (E(ex)) and the average formal charge on Br (q(Br)(+)) of BDE-209, reflecting the difficulty for the excitation of BDE-209 and for the departing of Br atom, respectively, were changed by the reaction fields formed by the different solvents. E(ex) and q(Br)(+) linearly correlated with the photolytic activity (logk). This study is helpful to better understand the photolytic behavior of BDE-209 in different media.
在四氢呋喃、二氯甲烷、异丙醇、丙酮、乙醇、甲醇、乙腈和二甲基亚砜中研究了十溴二苯醚（BDE - 209）的光解作用。在不同溶剂中发现光解速率和量子产率存在显著差异。与之前的推断不同，在本研究中，溶剂的供氢效率和供电子效率并非光解速率的决定性因素，这一点由BDE - 209在四氯化碳（一种无氢且难以供电子的溶剂）中的快速光解得到证明。除了加氢过程外，光解过程中可能会发生分子间聚合。进行了密度泛函理论（DFT）计算以了解BDE - 209在不同溶剂中的分子性质。不同溶剂形成的反应场改变了BDE - 209的最低单重态垂直激发能（E(ex)）和溴上的平均形式电荷（q(Br)(+)），它们分别反映了BDE - 209激发的难易程度和溴原子离去的难易程度。E(ex)和q(Br)(+)与光解活性（logk）呈线性相关。本研究有助于更好地理解BDE - 209在不同介质中的光解行为。
