A simple method for the fast calculation of charge redistribution of solutes in an implicit solvent model

We propose and demonstrate the usefulness of a method, defined as generalized Born electronegativity equalization method (GBEEM) to estimate solvent-induced charge redistribution. The charges obtained by GBEEM, in a representative series of small organic molecules, were compared to PM3-CM1 charges in vacuum and in water. Linear regressions with appropriate correlation coefficients and standard deviations between GBEEM and PM3-CM1 methods were obtained (R = 0.94, SD = 0.15, F-test = 234, N = 32, in vacuum; R = 0.94, SD = 0.16, F-test = 218, N = 29, in water). In order to test the GBEEM response when intermolecular interactions are involved we calculated a water dimer in dielectric water using both GBEEM and PM3-CM1 and the results were similar. Hence, the method developed here is comparable to established calculation methods. (C) 2002 Elsevier Science B.V. All rights reserved.