Theoretical Studies on OH⁻+NH₂Cl Reaction: Nucleophilic Substitution at Neutral Nitrogen.

The SN2 and proton transfer (PT) pathways for OH − + NH 2 Cl reaction are represented by employing various electronic structure computations. Both back-side SN2 and PT channels are exothermic and stationary points of PESs are below the reactant asymptote. Overall, the PES is similar to the C-centered SN2 reactions. Conversely, ion-dipole complex was not found for OH − + NH 2 Cl system. The N–HOH/NH–Cl hydrogen bond characterizes on either side of the reaction barrier of nitrogen complexes. Moreover, a halogen-bonded complex (HO−–ClNH2) and two types of H-bond complexes (HONH2–Cl− and Cl−–HONH2) were described, predicting an important role in dynamics. The PT pathway may be the major channel in the title system, which is contradictory to OH − + CH 3 Cl and F − + NH 2 Cl reactions. Here, MP2, B3LYP and CAM-B3LYP methods show overall excellent consistency with CCSD(T)/CBS energies and are recommended to carry out dynamics simulations. The PES of OH– + NH2Cl reaction shows two main pathways, SN2 and proton transfer, of which the later may be more competitive than SN2 pathway. A halogen-bond complex HO–ClNH2 is obtained, that could play an important role in dynamics. MP2, B3LYP and CAM-B3LYP methods are recommended to perform chemical dynamics simulations. [ABSTRACT FROM AUTHOR]