Growth and characterization of l-Histidinium chloroacetate (LHCA): A new nonlinear optical material

A new second order NLO semiorganic crystalline material l-Histidinium trichloroacetate LHCA with the chemical formula {[(C3N2H4)CH2CH(NH3)(CO2)]+CH2ClCOO−} was synthesized and single crystals were grown in first time by slow solvent evaporation technique in an aqueous solution medium at ambient temperature. The grown crystal of dimension 10 × 11 × 12 mm3 was harvested in a period of 30 days. Single crystal X-ray diffraction data reveals that the crystal belongs to the triclinic system with noncentrosymmetric space group P1. The peaks in powder X-ray diffractogram were indexed corresponding to the (hkl) plane orientations showing the crystalline purity and perfection. The characteristic vibrational frequencies corresponding to functional groups in LHCA molecule were confirmed by FTIR spectral analysis. The locations of hydrogens attached with different chemical moieties were identified by their resonance in 1H1 NMR spectrum. UV – vis – NIR spectrum shows LHCA has lower cut-off wavelength at 220 nm in UV region and the direct optical band gap energy of 3.52 eV. Dielectric behavior of the LHCA crystal was studied for various frequencies at different temperatures. SHG efficiency was found to be 1.8 times greater than KDP. TG/DSC curve reveals that LHCA possess good thermal stability compared with most of the organic compounds. Mechanical strength of the crystal was studied by Vicker's hardness Test.