Understanding the NN bond cleavage and the electrostatic properties of isoniazid drug molecule via theoretical charge density study

✍ Scribed by Gnanasekaran Rajalakshmi; Balu Devipriya; Azhagesan Renuga Parameswari; Arputharaj David Stephen; Poomani Kumaradhas

• Book ID: 104016847
• Publisher: Elsevier
• Year: 2011
• Tongue: English
• Weight: 826 KB
• Volume: 966
• Category: Article
• ISSN: 2210-271X
• DOI: 10.1016/j.comptc.2011.03.015

✦ Synopsis

Charge density distribution and the electrostatic properties of isoniazid drug molecule have been computed from HF and DFT methods with the basis set 6-311G ⁄⁄ using Bader's theory of atoms in molecules. The molecular geometric parameters predicted by DFT method are in agreement with the reported values. The predicted NAN bond distance is 1.414 Å. The dihedral angle between the pyridine ring and the hydrazide group is 27.9°, indicates that these two groups are not coplanar in the molecule. The CAN bond distances in the molecule are not equal. The electron density q bcp (r) and the Laplacian of electron density r 2 q bcp (r) of NAN bond are 2.131 eÅ -3 and À12.5 eÅ À5 respectively. The high degree of electronic charge density depletion at the bond critical point and the low bond dissociation energy of NAN bond confirm that this bond is the weakest bond in the molecule, which cleaves during the catalase-peroxidase reaction. A large electronegative potential region is found at the vicinity of O(1) and N(1) atoms, which are the nucleophilic sites of the molecule. The dipole moment of the molecule is 2.04 Debye, implies, isoniazid is a polar molecule.