Shao Xin, Xue Junfei, Jiang Junjie, Zeng Xiaoqing
Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, China.
J Phys Chem Lett. 2024 Jul 18;15(28):7327-7334. doi: 10.1021/acs.jpclett.4c01750. Epub 2024 Jul 10.
Methanesulfenic acid, CHSOH, is a fleeting intermediate in the ·OH-initiated oxidation reactions of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) in the atmosphere. Herein, we report the characterization and photochemistry of CHSOH in Ar- and N-matrices at 10 K. The characterization of CHSOH with matrix-isolation IR and UV-vis spectroscopy is supported by D and C isotope labeling experiments and quantum chemical calculations. In line with the observed absorption at 260 nm for CHSOH, its photolysis at 254 nm leads to dissociation by yielding the novel water complex HCS···HO, which exhibits a five-membered ring structure with intermolecular S···HO and CH···O hydrogen bonding interactions. Upon further irradiation at 193 nm, the HCS···HO complex undergoes dehydrogenation to form CS···HO, which can further convert to HC(O)SH under irradiation at 254 nm. When the photolysis of CHSOH was performed in an O-doped Ar-matrix, methanesulfonic acid (MSA, CHSOH) was obtained as the oxidation product.
甲亚磺酸（CHSOH）是大气中·OH引发的二甲基硫醚（DMS）和二甲基二硫醚（DMDS）氧化反应中的一种瞬态中间体。在此，我们报道了在10 K的氩气和氮气基质中CHSOH的表征及光化学性质。通过氘和碳同位素标记实验以及量子化学计算，支持了用基质隔离红外光谱和紫外可见光谱对CHSOH的表征。与观察到的CHSOH在260 nm处的吸收一致，其在254 nm处的光解通过生成新型水络合物HCS···HO导致解离，该络合物呈现出具有分子间S···HO和CH···O氢键相互作用的五元环结构。在193 nm处进一步辐照时，HCS···HO络合物发生脱氢反应形成CS···HO，在254 nm辐照下它可进一步转化为甲硫羟酸（HC(O)SH）。当在掺氧的氩气基质中进行CHSOH的光解时，得到甲磺酸（MSA，CHSOH）作为氧化产物。
