A theoretical study of C–H bond of CH4 activation catalyzed by VO2+ in gas phase

The mechanism of C–H bond of CH4 activation catalyzed by VO2+(1A1/3A′) has been investigated by using density functional theory (DFT) at the CCSD/6-311G(2d,p)//B3LYP/6-311G(2d,p) level. According to our calculation results, the four channels have been well-established and the reactivity patterns on the singlet and triplet PESs are almost similar. And the reaction proceeds in three distinct manners yielding the [V(OCH2)+ + H2O] products, the [V(OH2)+ + CH2O] products, the [OV(OCH2)+ + H2] products and the [VO+ + CH3OH] products. Specially, the crossing points (CPs) between the different PESs have been located by means of the intrinsic reaction coordinate (IRC) approach used by Yoshizawa et al., and corresponding minimum energy crossing points (MECPs) that we obtained by the mathematical algorithm proposed by Harvey et al. has also been employed. In addition, the frontier molecular orbital interaction analysis about 1TS1, 3TS1, 1TS4 and 3TS4 are used to gain useful information about the C–H bond of CH4 activation by VO2+.