Inter/Intramolecular Hydrogen Bond Strength in {N-[(3-BOROMO) PHENYL]-5 Methylisoxazole 4-Carboxamide}: DFT and AIM Calculations

Molecular structure and the inter/intramolecular hydrogen bond in the monomer and dimer of {N-[(3-boromo) phenyl]-5 methylisoxazole 4-carboxamide}[1] have been investigated with quantum mechanical calculations using density functional theory and atoms in molecules analysis[2] at the B3LYP[3,4] level using 6-311++G** basis set. The formation of inter/intramolecular hydrogen bonds has a very pronounced effect on molecular structure and drug properties of the compound. Electronic charge density (ρ) and its Laplacian (∇2ρ) at critical points of hydrogen bonds are the powerful tools to estimate the nature and the strength of intra/intermolecular hydrogen bonds. These parameters are computed for the titled compound by using the AIM 2000 program[5]. The target molecule have a strong intramolecular hydrogen bond strength of about 96 kJ mol-1 in both of the monomer and dimer and a weak intermolecular hydrogen bond strength of about 10 kJ mol-1 .