Investigation on Molecular Structure and Electronic Properties of Zinc (II) Complex with 2-acetylpyridinenicotinichydrazone Ligand

Abstract

In the present study, the structural parameter, the electronic and nonlinear optical properties of three Zn (II) halido complexes of the type [Zn (Hal)2HL] (Hal = Cl, 1; Br, 2; I, 3; HL = 2-acetylpyridine nicotinic hydrazone) have been theoretically investigated in detail. Two of the studied complexes [ZnCl2(HL), [ZnBr2(HL)] have been synthesized before, and some molecular properties have been determined, however, the new complex [ZnI2(HL)] is theoretically modeled for the first time. The polarizability (α), dipole moment (µ) and the first-order hyperpolarizability (β) of the compounds have been investigated using the Density Functional Theory (DFT) based on the B3LYP density functional with basis set combinations. In calculations, LANL2DZ and a mixed basis set of LANL2DZ (for Zn and I) and 6-311G (for other atoms) are used in the gas-phase geometry optimization. In addition, the highest occupied molecular orbital energy (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the compounds in the ground state were calculated by using the same method and the energy band gap (Eg = ELUMO-EHOMO) was obtained from frontier molecular orbitals. The equilibrium state (ground state) dipole moment value of the studied complex was calculated as 12.61 and 12.74 Debye by B3LYP/GENECP/LANL2DZ-6-311G and B3LYP/LANL2DZ method, respectively. The energy gap values of complexes 1-3 are calculated as 1.73/1.38/1.15 eV at the B3LYP/LANL2DZ and are calculated as 3.61/2.28/2.18 eV at the B3LYP/MIX respectively. The energy gap values of complexes 1-3 decrease in the order complex 1>complex 2>complex 3. The approximate geometry of the molecules in three dimensions was drawn in the Gauss View 5.0 molecular imaging program, and all theoretical calculations were used with the Gaussian 09W package program.