Dihalogenated Methylperoxy Radicals: Spectroscopic Characterization and Photodecomposition by Release of HOC
Bo Lua, Chao Songa, Jie Liua, Tarek Trabelsi b,Joseph S. Francisco*b, Lina Wangc, and Xiaoqing Zeng*ac（曾小庆）
aCollege of Chemistry, Chemical Engineering and Materials Science,Soochow University, Suzhou 215123 (P. R. China)
bDepartment of Earth and Environmental Science and Department of Chemistry, University of Pennsylvania, Pennsylvania 19104 (USA)
cDepartment of Chemistry, Fudan University, Shanghai 200433 (P. R. China)
Chem. Eur. J. 2020, 26, 2817--2820
Two atmospherically relevant dihalogenated methylperoxy radicals CHX2OO. (X=F and Cl) have been generated through O2‐oxidation of the corresponding alkyl radicals CHX2. in the gas phase. The IR spectroscopic characterization of both radicals in cryogenic Ar‐ and N2‐matrices (15 K) is supported by 18O‐labeling and ab initio calculations at the UCCSD(T)/aug‐cc‐pVTZ level. Upon 266 nm laser irradiation, both radicals decompose mainly by releasing hydroxyl radicals (→HO.+X2CO) via the intermediacy of intriguing α‐hydroperoxyalkyl radicals (.CX2OOH), implying that the photooxidation of dihalogenated hydrocarbons might serve as important sources of HO. radicals in the atmosphere.