Prediction of physicochemical properties of organic molecules using van der Waals surface electrostatic potentials.

The generalized interaction properties function (GIPF) methodology developed by Politzer and coworkers, which calculated molecular surface electrostatic potential (MSESP) on a density envelope surface, was modified by calculating the MSESP on a much simpler van der Waals (vdW) surface of a molecule. In this work, vdW molecular surfaces were obtained from the fully optimized structures confirmed by frequency calculations at B3LYP/6-31G(d) level of theory. Multiple linear regressions for normal boiling point, heats of vaporization, heats of sublimation, heats of fusion, liquid density, and solid density were performed using GIPF variables from vdW model surface. Results from our model are compared with those from Politzer and coworkers. The surface-dependent beta (and gamma) values are dependent on the surface models but the surface-independent alpha and regression coefficients (r) are constant when vdW surface and density surface with 0.001 a.u. contour value are compared. This interesting phenomenon is explained by linear dependencies of GIPF variables.