Capture of SO3 Isomers in the Oxidation of Sulfur Monoxide with Molecular Oxygen

Zhuang Wu, Bo Lu, Ruijuan Feng, Jian Xu, Yan Lu, Huabin Wan, André K. Eckhardt, Peter R. Schreiner, Changjian Xie, Hua Guo, and Xiaoqing Zeng
Chem. Commun. 2018, 54, 1690–1693. DOI: 10.1039/C7CC09389F
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When mixing SO with O₂ in N₂, Ne, or Ar, an end-on complex OS–OO forms in the gas phase and can subsequently be trapped at cryogenic temperatures (2.8–15.0 K). Upon infrared light irradiation, OS–OO converts to SO₃ and SO₂ + O with the concomitant formation of a rare 1,2,3-dioxathiirane 2-oxide, i.e., cyclic OS(O)O. Unexpectedly, the ring-closure of ¹⁶OS–¹⁸O¹⁸O yields a ca. 2 : 1 mixture of cyclic ¹⁸OS(¹⁶O)¹⁸O and ¹⁶OS(¹⁸O)¹⁸O. The characterization of OS–OO and OS(O)O with IR and UV/Vis spectroscopy is supported by high-level ab initio computations.