Theoretical study on the reaction of the ground state 2Δ of TiS+ with oxygen-transfer reagent:: TiS++H2O→TiO++H2S in the gas phase

The reaction mechanism of the ground state (2)Delta of TiS+ with oxygen-transfer reagent: TiS+ + H2O --> TiO+ + H2S, in the gas phase has been proposed and investigated by ab initio methods with 6-31G** basis set for non-metal atoms and the effective core potentials of Lanl2dz for Ti. The reaction is proceeding via,two steps with seven stationary points (reactants, three intermediate complexes: (a), (b) and (c) two transition states: TS1 and TS2, and products) on the reaction potential surface which involved two 1,3-hydrogen shift reactions from oxygen atom to sulfur atom via a four-center transition state. The activation barriers of the two transition states are -54.0 and -65.1 kcal/mol, respectively, at MP4 (SDTQ)/6-31G**//MP2/6-31G** level plus zero-point energy relative to the reactants, which-indicates that cationic titanium sulfide is favorable to this type of reaction and the collision rate of-the reactants forming the complex (a) should be the main factor that determines the reaction rate. (C) 2003 Elsevier Science B.V. All rights reserved.