Addition complexes of dimethyl sulfide (DMS) and OH radical and their reactions with O2 by ab initio and density functional theory

Two weakly bound complexes between CH3SCH3 (DMS) and OH, via 2-center-3-electron (2c-3e) bonding and dipole-dipole interaction, have been identified by density functional theory (DFT-B3LYP). The 2c-3e bonding complex is more stable at Gaussian-2 level with -31 kJ/mol relative to DMS+OH. Similar structures are found for the complex of CH3SH with OH. Subsequent reaction of the 2c-3e DMS OH adduct with O-2 is also studied by DFT. A complex between the DMS-OH adduct and O-2 with a strong S-O single bond characteristic is identified. Dissociation or H-atom abstraction of this complex could lead to the formation of (CH3)(2)SO. (C) 2001 Elsevier Science B.V. All rights reserved.