Crystal structure of single crystals of nonlinear optical l-histidinium trichloroacetate

Single crystals of a new histidinium salt: l-histidinium trichloroacetate {abbreviated as LHTCA; [(C3N2H4) CH2CH (NH3) (CO2)]+ CCl3COO−} were grown by slow evaporation of an aqueous solution at room temperature. The compound crystallizes in a non-centrosymmetric space group P21 of monoclinic system with cell parameters a = 5.4505(18) Å, b = 25.769(8) Å, c = 9.210(2) Å and β = 99.98(2)° with Z = 4. The structure has been refined to an R-value of 0.05 for 2539 observed reflections using three-dimensional X-ray diffraction data. The vibrational structure of the compound confirms the presence of various functional groups in the molecule. The UV-Vis-NIR spectrum shows a good transparency in the whole of the region from ultraviolet to near IR. The Kurtz-Perry powder SHG measurement confirms the frequency doubling of the crystal and its powder SHG efficiency was measured as deff = 0.33 deff (KDP).