AGOA: A Hydration Procedure and Its Application to the 1-Phenyl-β-Carboline Molecule

Most chemistry and biochemistry occur in condensed media, in particular, aqueous solutions. Thus, the proper simulation of these processes has to take into account the solvent effects. Consequently, since the pioneer work of Born on ionic solvation, these solvent effects have been shown to be of fundamental importance for many chemical and biological processes and have then been receiving considerable attention. There are basically three models to describe the solvent, namely, the continuum or dielectric model, the discrete or supermolecule model, and the discrete-continuum model, which attempts to combine the two previous ones. The continuum model treats the solvent as a structureless dielectric medium and the solute is inserted in a cavity. Since this is a classical macroscopic description there is not a unique way of integrating it into a quantum chemical description of the solute. Thus, there are many distinct implementations of the continuum model, ranging from sophisticated Poisson equation solutions on an isoelectronic surface to simple spherical dipole reaction field. However, independent of the implementation, the continuum models are not able to describe specific solutesolvent interactions, in particular, hydrogen bonds. In addition, the definition of the solute cavity and the dielectric constant are arbitrary. The discrete model treats the solvent as individual molecules, which interact with the solute via a parametric potential (classical models) or an instantaneous Coulombic interaction between the electrons and the nuclei of the solute and the solvent molecules AGOA: A Hydration Procedure and Its Application to the 1-Phenyl-β-Carboline Molecule