title: Theoretical spectroscopic study of seven zinc(II) complex with macrocyclic Schiff-base ligand.
abstract: Seven zinc complexes, which are [ZnL(1)](2+), [ZnL(2)](2+), [ZnL(3)](2+), [ZnL(4)](2+), [ZnL(5)](2+), [ZnL(6)](2+) and [ZnL(7)](2+), are studied as theoretically. Structural parameters, vibration frequencies, electronic absorption spectra and (1)H and (13)C NMR spectra are obtained for Zn(II) complexes of macrocyclic penta and heptaaza Schiff-base ligand. Vibration spectra of Zn(II) complexes are studied by using Density Functional Theory (DFT) calculations at the B3LYP/LANL2DZ. The UV-VIS and NMR spectra of the zinc complexes are obtained by using Time Dependent-Density Functional Theory (TD-DFT) method and Giao method, respectively. The agreements are found between experimental data of [ZnL(5)](2+), [ZnL(6)](2+) and [ZnL(7)](2+) complex ions and their calculated results. The geometries of complexes are found as distorted pentagonal planar for [ZnL(1)](2+), [ZnL(2)](2+) and [ZnL(3)](2+) complex ions, distorted tetrahedral for [ZnL(4)](2+) complex ion and distorted pentagonal bipyramidal for [ZnL(5)](2+), [ZnL(6)](2+) and [ZnL(7)](2+) complex ions. Ranking of biological activity is determined by using quantum chemical parameters and this ranking is found as: [ZnL(7)](2+)>[ZnL(6)](2+)>[ZnL(5)](2+)>[ZnL(3)](2+)>[ZnL(2)](2+)>[ZnL(1)](2+).
authors: Chemistry Department, Faculty of Science, Cumhuriyet University, 58140 Sivas, Turkey. Electronic address: krysayin@gmail.com.
authors: Koray
authors: K
authors: Sayin
authors: Chemistry Department, Faculty of Science, Cumhuriyet University, 58140 Sivas, Turkey.
authors: Sultan Erkan
authors: SE
authors: Kariper
authors: Chemistry Department, Faculty of Science, Cumhuriyet University, 58140 Sivas, Turkey.
authors: Tuba Alagöz
authors: TA
authors: Sayin
authors: Chemistry Department, Faculty of Science, Cumhuriyet University, 58140 Sivas, Turkey.
authors: Duran
authors: D
authors: Karakaş
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D011789:Quantum Theory; D012545:Schiff Bases / Q000737:chemistry*; D013057:Spectrum Analysis; D015032:Zinc / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D012545:Schiff Bases; D015032:Zinc
keywords: DFT studies; Macrocyclic Schiff-base ligand; Spectroscopic studies; Zn(II) complexes