Comparative Study of Properties of L-Histidine and L-Histidine Nickel Nitrate Hexahydrate Crystals Grown by Slow Evaporation

Abstract

L-Histidine (LH) is an amino acid. It is an organic material. L-Histidine Nickel Nitrate Hexahydrate (LHNNH) is a semi organic material. It is a complex of bivalent nickel ion with L-Histidine amino acid. Complexes of bivalent metal ions with amino acids are generally good NLO materials. Crystals of L-Histidine and L-Histidine Nickel Nitrate Hexahydrate (LHNNH) have been successfully grown by slow evaporation method using water as solvent. The crystal structure and lattice parameters of LH and LHNNH are determined by Single crystal X-ray diffraction analysis. The functional groups in LH and LHNNH are confirmed by FTIR analysis. With the help of UV-Vis spectroscopy the optical band gap and optical transparency are studied. The chemical composition of LH and LHNNH are studied by CHN and EDAX analysis. Thermally stability and thermal phase transitions of LH and LHNNH are analyzed by TGA/DTA. The Second Harmonic Generation (SHG) efficiency of LH and LHNNH have been experimentally estimated. Introduction: L-Histidine is an optically active α-amino acid and is a tridentate ligand that has an imidazole ring, amino and carboxylate groups. Amino acids are the potential candidates for optical second harmonic generation because they contain chiral carbon atom and crystallize in non-centro symmetric space groups and it is an essential criterion for nonlinear application [1]. Amino acids are interesting materials for NLO applications. Complexes of amino acids with inorganic salts are promising materials for optical Second Harmonic Generation. In recent years semi organic crystals have emerged as extremely promising building blocks for NLO materials. They share the properties of both organic and inorganic materials. Amino acids are interesting materials for NLO applications, as they exhibit molecular chirality, absence of strongly conjugated bonds and zwitterionic nature of the molecule [2].