Template synthesis of two new supramolecular zinc(II) complexes containing pentadentate N3O2 semicarbazone ligand: Nanostructure synthesis, Hirshfeld surface analysis, and DFT studies

Two new zinc(II) complexes, [Zn(H(2)dapsc) (CH3OH)(2)][ZnBr2Cl2] (1) and [Zn(H(2)dapsc), (CH3OH)Br] Br center dot(CH3OH) (2), where H2dapsc is 2,6-diacetylpyridine bis(semicarbazone), were synthesized using a template method in which the pentadentate N3O2 semicarbazone ligand derived from [1 + 2] condensation of 2,6-diacetylpyridine and semicarbazide in the presence of zinc(II) ion as template agent. These compounds were characterized by IR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Their single crystal X-ray structures showed that in both complex cations, the metal center has a distorted pentagonal-bipyramidal geometry in which the semicarbazone (H2dapsc) ligand occupies the equatorial plane, while the axial positions occupy by two methanol, ligands in (1) and two bromo and methanol ligands in (2). Furthermore, the impact of the close intermolecular contacts on the crystal packing of (1) and (2) have been further studied using Hirshfeld surface analysis. Density Functional Theory (DFT) method was applied for the calculation of HOMO-LUMO energy gap, atomic charges and vibrational frequencies of title complexes. Moreover, the nanostructure of zinc complex was synthesized by a sonochemical method and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), FT-IR spectroscopy, and elemental analysis. (C) 2017 Elsevier B.V. All rights reserved.