SYNTHESIS OF (Z)-N'-(PHENYL(PYRIDIN-2-YL)METHYLENE)-NICOTINOHYDRAZIDE: STRUCTURAL CHARACTERIZATION AND ANTIOXIDANT ACTIVITY SCREENING

Abstract

Asymmetrical ligand ( Z )- N '-(phenyl(pyridin-2-yl)methylene)nicotinohydrazide ( I ) was synthesized from the condensation of nicotinic acid hydrazide with 2-benzoylpyridine. The compound was characterized by physicochemical analyses, elemental analysis, FTIR, 1 H and 13 C NMR spectroscopy techniques. The structure of the compound was determined by a single-crystal X-ray diffraction study. The ligand crystallizes in the triclinic space group P-1 with the following unit cell parameters: a = 8.2699 (11) A, b = 8.6514 (8) A, c = 11.583 (11) A, a = 91.308 (3)°, b = 94.155 (5)°, g = 109.008 (4)°, V = 755.17 (14) A 3 , Z = 2, R 1 = 0.050, wR 2 = 0.145. The carbonohydrazone moiety of the molecule is slightly twisted as reflected by the torsion angles values of -1.2 (2)° [O1—C13—N3—N2]. The dihedral angle between the mean planes of the pyridine rings is 11.799 (9)°. The crystal packing of compound ( I ) is stabilized by intramolecular N(carbohydrazide)–H···N(pyridine) and intermolecular C(phenyl)–H···O(amide) and C(phenyl)–H···N(hydrazino) hydrogen bonds, leading to the formation of sheets parallel to ac plane. The compound screened for antioxidant activity showed variable DPPH inhibition value for different concentrations of DPPH solution.