Structure and spectral properties of L-histidinium dipicrate dihydrate

Synthesis, growth, optical, mechanical, thermal, dielectric, and SHG properties of Triethylaminium picrate (TEAP) single crystal for nonlinear optical applications

Triethylaminium picrate (TEAP) crystals were grown using the slow evaporation solution growth method at ambient (35 °C) temperature. Salt was synthesized from Picric acid, and Triethylamine and methanol was used as solvents. The solution was mixed at a 1:1 ratio and evaporated slowly, produced yellow colour single crystal of TEAP with an average dimension of 19 × 8 × 5 mm3. The structure of the compound was determined by single-crystal X-ray diffraction (SCXRD) study, which confirms that the crystal is belongs to Orthorhombic crystal system, and its crystallinity was confirmed by the Bragg peak in the powder X-ray diffraction pattern. The superamolecular characteristic of the TEAP was confirmed by the Hirshfield analysis. CHN elemental analysis confirmed the stoichiometry and chemical composition of the synthesized complex salts. FT-IR and Polarized Raman spectral analyses confirmed the presence of different functional groups in the complex. UV-vis-NIR study identified the optical transmission window and the lower (TEAP) cut-off wavelength. Vickers' microhardness analysis determined the mechanical stability of the grown crystal. Studies of dielectric and AC conductivity were analyzed as a function of frequency. The thermogravimetry (TG) and differential thermal analysis (DTA) techniques were used to investigate the thermal behaviour of the material. The Kurtz-Perry powder technique was used to analyze the crystal's nonlinear optical properties (NLO) and found that its SHG efficiency was 1.5 times higher than that of potassium dihydrogen phosphate (KDP). The results from the obtained characterizations conclude that the TEAP crystal could be useful for NLO applications.

Synthesis, characterization, and thermal and computational investigations of the L-histidine bis(fluoride) crystal

Nonlinear optical materials have been investigated recently due to their potential technological applications in information storage and communications. In this context, semi-organic crystals can effectively combine the desired nonlinear optical properties of amino acids with the promising mechanical and thermal properties of inorganic materials. In this work, we have synthesized and characterized a semi-organic crystal of the amino acid l-histidine and hydrofluoric acid and investigated the chemical interactions between the organic and inorganic moieties. The crystal of l-histidine bis(fluoride) has been produced by slow solvent evaporation and characterized by X-ray diffraction (XRD) crystallography and thermogravimetric and differential thermal analyses. The XRD conducted using the Rietveld method shows that the unit cell is orthorhombic with the P2₁2₁2 space group and contains four l-histidine bis(fluoride) units. Both differential thermal analysis and temperature-dependent XRD show that the crystals are thermally stable up to 191°C and do not undergo phase transition. The computational Hirshfeld surface analysis of the crystal structure reveals the main intermolecular interactions. Density functional theory has been employed to calculate the ionic interaction energy and electrostatic potential maps and confirm the spontaneity of ionic association at 191°C. The combined experimental and computational results show that the thermal stability of the semi-organic l-histidine bis(fluoride) crystal makes it suitable for nonlinear optical applications in optical sensing and communication systems.

L-Methioninium picrate

Single crystals of l-methioninium picrate were obtained by evaporation of aqueous solution containing equimolar quantities of each component. l-Methioninium picrate crystallizes in the monoclinic system (space group P21, Z=2). The asymmetric unit contains one l-methioninium cation and one picrate anion. The carboxyl group of the cation forms an O-H⋯O hydrogen bond with the phenoxy oxygen atom and has an O⋯O distance of 2.669(3)Å. The protonated amino group of the l-methioninium cation forms N-H⋯O hydrogen bonds with the phenoxy oxygen atom of the picrate anion and the carbonyl oxygen atom of the symmetry related cation. The infrared and Raman spectra are recorded and discussed.

Synthesis, crystal growth and physiochemical characterization of organic NLO crystal: L-ornithinium dipicrate (LODP)

L-ornithinium dipicrate (LODP) has been synthesized and good quality single crystals were grown by slow evaporation method at room temperature. Single crystal XRD confirms that the grown crystal belongs to the monoclinic system with the noncentrosymmetric space group P21. Powder X-ray diffraction study confirms the crystalline nature of the compound. FTIR spectral analysis confirms the functional group in the synthesized compound. Thermogravimetric and differential thermal analyses reveal the thermal stability of the crystal. The optical absorption spectrum shows the absence of absorption between 475 nm and 800 nm. The dielectric measurements were carried out to estimate the dielectric parameters of the grown crystal in the frequency range from 50 Hz to 5 MHz at various temperatures. The second harmonic property has been investigated by Kurtz-Perry powder technique. The relative SHG efficiency of LODP is found to be 14.57 times greater than that of the reference material KDP.

Experimental and theoretical studies of 2,5-dichloroanilinium picrate

Organic 2,5-dichloroanilinium picrate crystal was grown by using slow evaporation solution technique. The lattice parameter was estimated by powder X-ray diffraction. The absence of absorption at around Nd:YAG fundamental wavelength was confirmed by ultraviolet-visible absorption study. The vibrational analyses confirm the various functional groups present in the grown crystal. The NMR study confirms the presence of chemical environment of hydrogen in the title crystal. The thermogravimetric (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) traces reveals the thermal stability of the compound. The second harmonic generation (SHG) of the crystal was confirmed by Kurtz Perry powder technique. The theoretical studies such as first-order hyperpolarizability (β), molecular orbitals, electronic excitation and electrostatic potential (ESP) were performed using Gaussian 03W software at HF/6-31G (d) level.