Theoretical study of the reaction of Mo+ with SCX (X=S, O) in gas phase

Density functional theory (DFT) calculations have been performed to explore the sextet, quartet, and doublet potential energy surfaces of C-X (X=S, O) bond activation in CS2 and SCO molecules by gas-phase Mo+ cation, in order to better understanding the reaction mechanism of second-row metal cations reacting with SCX (X=S, O). The minimum energy reaction path is found to involve the spin inversion in the different reaction steps. The crossing points (CPs) of the different potential energy surfaces (PESs) have been localized with the approach suggested by Yoshizawa et al. [K. Yoshizawa, Y. Shiota, T. Yamabe, J. Chem. Phys. 111 (1999) 538]. The potential energy curve-crossing dramatically affects reaction mechanism. The present results show that the reaction mechanism is insertion-elimination mechanism both along the C-S and C-O bond activation branches, but the C-S bond activation is much more favorable than the C-O bond activation in energy. All theoretical results not only support the existing conclusions inferred from early experiment, but also complement the pathway and mechanism for this reaction.