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).