Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of manganese (II) complex of picolinate: A combined experimental and computational study

Abstract

A novel manganese (II) complex with picolinic acid (pyridine 2-carboxylic acid, Hpic), namely, [Mn(pi-c)(2)(H2O)(2)] was prepared and its crystal structure was fully characterized by using single crystal X-ray diffraction. Picolinate (plc) ligands were coordinated to the central manganese(II) ion as bidentate N,O-donors through the nitrogen atoms of pyridine rings and the oxygen atoms of carboxylate groups forming five-membered chelate rings. The spectroscopic characterization of Mn(II) complex was performed by the applications of FT-IR, Raman, UV-vis and EPR techniques. In order to support these studies, density functional theory (DFT) calculations were carried out by using B3LYP level. IR and Raman spectra were simulated at B3LYP level, and obtained results indicated that DFT calculations generally give compatible results to the experimental ones. The electronic structure of the Mn(II) complex was predicted using time dependent DFT (TD-DFT) method with polarizable continuum model (PCM). Molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength were investigated by applying natural bond orbital (NBO) analysis. Nonlinear optical properties of Mn(II) complex were investigated by the determining of molecular polarizability (alpha) and hyperpolarizability (beta) parameters. (C) 2015 Elsevier B.V. All rights reserved.