Determination of net atomic charges using a modified partial equalization of orbital electronegativity method. IV. Application to hypervalent sulfur- and phosphorus-containing molecules

The parameters for an empirical point charge calculation method, Mulliken Population Constrained Potential Derived–Modified Partial Equalization of Orbital Electronegativity (MPCPD–MPEOE) method, for hypervalent sulfur, phosphorus, and the atoms bonded to these atoms, were determined. A new empirical method, MPCPD, which has inherent advantages over both the Mulliken population and potential derived methods, is proposed here. The MPCPD net atomic charges are transferable and reproduce the electrostatic potential. The electrical properties were calculated with the MPCPD and MPCPD–MPEOE charges. These properties agreed well with experimental results and with 6-31G** ab initio results. The MPEOE parameters for the sulfur atom in aromatic molecules and trivalent phosphorus in phosphite molecules were also determined. The dipole moments calculated with the MPCPD–MPEOE point charges agreed well with experimental results. All the parameters obtained in this work are consistent with those obtained in our previous work. © 1995 by John Wiley & Sons, Inc.