Incorporation of hydration effects within the semiempirical molecular orbital framework. AM1 and MNDO results for neutral molecules, cations, anions, and reacting systems

A recently developed continuum model for the incorporation of hydration effects into the AM1 and MNDO semiempirical molecular orbital Hamiltonians is evaluated by comparison with representative experimental data. The new method gives quantitatively correct predictions for the aqueous-phase conformational behavior of H 3 N + CH 2 CH 2 CO 2 - and the aqueous-phase activation energetics of the S N 2 reaction of Cl - and CH 3 Cl