Synthesis, X-ray structure, spectroscopic characterization and nonlinear optical properties of Nickel (II) complex with picolinate: A combined experimental and theoretical study

A novel Nickel (II) complex with picolinate was prepared and its structural characterization was carried out by X-ray diffraction method. Its vibration spectra (FT-IR and Raman) were recorded to investigate the vibrational wavenumbers and the coordination environment of Ni(II) ion. In order to demonstrate electronic transitions and molecular charge transfers within complex 1, UV-vis spectrum was measured in ethanol solvent. Furthermore, the density functional theory (DFT) calculations were performed to both support the experimental results and convert this study to more advanced work. The geometry optimization and calculations of vibration spectra and electronic transitions were performed by using DFT level. Obtained small HOMO-LUMO energy gap displayed that complex 1 can be easily polarized and molecular charge transfer occurs within complex 1. Molecular stability and hyperconjugative interactions were investigated by applying natural bond orbital (NBO) analysis. The nonlinear optical properties of complex 1 were determined, and obtained results showed that complex 1 can be considered as a potential candidate for NLO material. (C) 2015 Elsevier B.V. All rights reserved.