Theoretical Studies On Ni~+ And NiAl~+ Activated C-H And C-C Bonds Of Cyclohexane In Gas Phase

The activation of C-H and C-C bonds in the alkanes catalyzed by transition metal ions has very high research value in petrochemistry,organic chemistry and catalysis because of the strong interaction between transition metal ions and alkanes,this force causes the C-H and C-C bonds of the alkanes have been broken.In order to find a catalyst with higher activation performance,we studied the reaction of cyclohexane with single ion Ni~+ and double ion NiAl~+,respectively.In this paper,based on the density functional theory,potential energy surface theory and transition state theory in quantum chemistry calculation,the reaction mechanisms of Ni~+and NiAl~+catalyzed cyclohexane have been studied by using B3 LYP method.Through theoretical calculations,we get the transition states involved in the reaction,the optimized configuration and related parameters of the intermediates,and draw the potential diagram of the reaction,which help us to get further analysis and description of the reaction mechanism.The whole paper consists of four chapters:In the first chapter,we explain the concept,development and application of quantum chemistry,then describes the condition of activating alkanes by transition metal ions,and finally summarizes the main work in this paper.In the second chapter,the relevant quantum chemical theory,calculation basis sets and calculation methods are describedIn the third chapter,the reaction mechanism of Ni~+ catalyzed C-H bonds and C-C bonds in cyclohexane is studied.The calculation results show that the activation reaction of C-H bonds and C-C bonds is a competitive reaction,but the activation of C-C bond is more favorable,and these two kinds of reactions are only in the double state potential energy surface,no potential energy surface crossing.In the fourth chapter,the reaction mechanism of NiAl~+ catalyzed C-H bonds and C-C bonds in cyclohexane is studied.The results show that NiAl~+has particularity that only activates C-H bonds.The reaction has potential energy surface crossing and the products are mixtures of singlet and triplet states.