Reaction Mechanism In Gas Phase Of Theoretical Study On The Transition-metal Sufide Cations With COS

Interest in transition-metal sulfides arises from their significance in industrial catalysis and biology. In industry, transition-metal oxides are used as versatile catalysts in many applications, however, for some processes their reactivity is too high and non-specific product formation occurs. In contrast, transition-metal sulfides are less reactive and susceptible to poisoning and can show higher selectivity. Transition metal sulfides also play a particular role in biochemistry in which heterometallic sulfur complexes form the active sites in several metalloenzymes. In fact, the transition-metal-ion chemistry has been an active area for both experimental and theoretical studies.According to the theory of two-state reactivity, we studied the reactions of transition-metal cation with COS in the gas phase by using density functional theory(DFT) at corresponding level. All the calculations were carried out with Gaussian.In Chapter1, elementary theory and quantum chemistry computation methods is briefly introduced. Chapter2describe the progress and application of quantum chemistry and transition-metal cation chemistry as well as the development and the present situation of TSR.In Chapters3,4and5, the gas phase reactions of YS, MoS+and CrS+with COS have been studied carefully using B3LYP methods and the activation of N-O, C-O and C-H bonds have been emphasized, respectively. The potential energy surface crossing behaviors have been discussed in detail. Firstly, for each reaction system, all molecular geometries were fully optimized on respective ground state and the lowest excited state PESs by high-level quantum chemistry calculation methods. Vibrational frequency calculations and intrinsic reaction coordinate (IRC) methods were used to characterize the reaction path channels on two PESs. Where after, a series of crossing points (CPs) involving the structures and energy values has been located and the spin inversion behaviors by which the reaction system can hop from one PES to another by effective spin-orbital coupling have been inspected. Finally, the energetically more favorable channel was confirmed according to thermodynamic and dynamic data. All of our calculated results in this thesis are in agreement with the early experimental findings.