Study of hydrogen bonding ability of organic molecules using electrostatic potential and electric field mapping: Role of hybridization displacement charge

Molecular electrostatic potential (MEP) and molecular electric field (MEF) maps of certain organic compounds were studied using optimised Hybridization Displacement Charge (HDC)-corrected Löwdin charges and Mulliken charges obtained using the Modified Neglect of Diatomic Differential Overlap (MNDO) method. The MEP minimum values computed by distributing the optimised HDC-corrected Löwdin charges according to the forms of squares of the corresponding valence s Slater atomic orbitals continuously in three dimensions were found to correlate linearly with their hydrogen bond accepting and donating abilities. The average MEF values near the appropriate sites on the van der Waals surfaces of the molecules were also found to correlate linearly with their hydrogen bond accepting abilities of molecules. Further, the MEP and MEF values computed using optimised HDC-corrected Löwdin charges were found to provide much better linear correlations with the observed hydrogen bond forming abilities of the molecules than those obtained using Mulliken charges.