Dynamic Reaction Mechanisms of ClO- with CH3Cl: Comparison Between Direct Dynamics Trajectory Simulations and Experiment

We have investigated the dynamic reaction mechanisms of *ClO- with CH3Cl (the asterisk is utilized to label a different Cl atom). Ab initio molecular dynamics simulations at the MP2/6-31+G(d,p) level of theory have been employed to compute the dynamic trajectories. On the basis of our simulations, the dynamic reaction pathways for the bimolecular nucleophilic substitution (S(N)2) reaction channel and S(N)2-induced elimination reaction channel are clearly illustrated. For the S(N)2 reaction channel, some trajectories directly dissociate to the final products of CH3O*Cl and Cl-, whereas the others involve the dynamic Cl-center dot center dot center dot CH3O*Cl intermediate complex. As to the S(N)2-induced elimination reaction channel, the trajectories lead to the final products of CH2O, HCl, and *Cl- through the dynamic Cl-center dot center dot center dot CH3O*Cl intermediate complex. More significantly, the product branching ratios of Cl- and *Cl- predicted by our simulations are basically consistent with previous experimental results (Villano et al. J. Am. Chem. Soc. 2009, 131, 8227-8233).