Quantum molecular study of S-methylated forms of sulfur mustard Original Research Article

An ab initio quantum molecular modeling of sulfur mustard and various S-methylated forms is presented in this work. The geometries, conformations and Mulliken charge distributions were obtained at the level HF/6-31G∗ computations for: neutral sulfur mustard (HD); the HD+ episulfonium; the 2-chloroethyl ethyl methyl sulfonium; the bis(2-chloroethyl)methyl (MeHD+) sulfonium and the bicationic form MeHD++ obtained by loosing a chloride in the chloroethyl branch of MeHD+. The conformational and the electrostatic situations are discussed with the aim to explain a possible rationale for detoxification of sulfur mustard proposed by Mozier and Hoffman. A theoretical reaction pathway of MeHD++ involving a closure way and a fragmentation way is proposed.