Syntheses, Crystal Structure and Theoretical Properties of Schiff Bases Obtained from Isoniazid and Pyridine‐2‐, 3‐, 4‐Carboxaldehyde and Their Zinc(II) Complexes

Abstract

The series of Schiff base ligands, N’‐(pyridine‐2‐ylmethylene)isonicotinohydrazide (I), N’‐(pyridine‐3‐ylmethylene)isonicotinohydrazide (II) and N’‐(pyridine‐4‐ylmethylene)isonicotinohydrazide (III), and the Zn(II) complexes of the ligands (I and II), [N’‐(pyridine‐2‐ylmethylene)isonicotinohydrazide]‐trichlorozincoate (IV) and [N’‐(Pyridin‐3‐ylmethylene) isonicotinohydrazide] trichlorozincoate (V) have been newly synthesized and their structures have been characterized by 1H, 13C NMR and FT‐IR spectroscopies, elemental analysis and single crystal X‐ray diffraction technique. The Hirshfeld surface analyses have been confirmed the importance of H‐atom contacts in establishing the packings. The ground state equilibrium geometries of the synthesized compounds are optimized at DFT/B3LYP/6‐311++G (d, p) and HF/6‐311++G (d, p) levels of theory (for the ligands) and B3LYP/GENECP method is used as the mixed basis sets of LANL2DZ (for Zn) and 6–311G (for other atoms) in the gas‐phase. The structural parameters obtained from the theoretical studies of the compounds are compared with their experimental ones. Their linear and nonlinear optical (NLO) properties are also calculated by the same methods. In the ground state, the energy band gaps (Eg) of the Schiff bases (I, II and III) have been calculated as 4.38 eV, 4.36 eV and 4.46 eV (at B3LYP) and 9.94 eV, 9.81 eV and 10.20 eV (at HF), respectively.