A new procedure, named AGOA, has been developed and implemented in a computer program written in FORTRAN 77 to explore the hydration structures of polar solutes using its molecular electrostatic potential (MEP). This procedure can be generalized to polar solvents other than water. It has been tested for several small molecules, and applied to complex molecules of pharmacological interest, such as the beta-carbolinic systems derived from indole. This is a stringent, but not general, test of the AGOA procedure and shows its robustness, flexibility and low computational costs, since either semiempirical or ab initio wavefunctions can be employed. The comparisons with procedures based upon the geometry optimization of the solute-water complex show the superior performance of the AGOA procedure for the anti and syn beta-carboline conformers, reassuring its use to comprehend and to quantify the specific interactions involved in solvent effects.
AGOA; hydration; solvent effects; beta-carboline; electrostatic potential
