Ab-initio molecular dynamics study of the S(N)2 reaction Cl-+ClCH2CN

Ab-initio molecular dynamics has been used to investigate the S(N)2 reactio n Cl-+ClCH2CN using two different exchange-correlation functionals. The res ults have been compared with available experimental data and with calculati ons at the MP2/6-311+G(d,p) level of theory. As a reference, comparison has also been made with calculations for the Cl-+CH3Cl reaction, for which acc urate experimental data and higher level ab-initio calculations are availab le. The similar to0 K energy profile has been calculated. It has been found that the minimum energy reaction pathway is characterized by the formation of a strong H-bond. Differences in the electron distribution along the pat hway of the two reactions have also been discussed.