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

Keywords:

Leflunomide , Triflunomide , DFT , AIM , Hydrogen Bond