Growth, Spectral, Thermal, Linear and Non-Linear Optical Characteristics of an Efficient Organic Crystal: L-Lysinium 5-Sulfosalicylate

Abstract

INTRODUCTIONNowadays, much consideration was provided to the nonlinear optical materials, which are the main focus of many research works going on around the world. The role of organic non-linear optical (NLO) materials with large optical nonlinearity in the fabrication of devices in telecommunication, optical information processing and high optical disk data storage is immensely significant [1][2][3][4][5][6][7]. Organic materials are the prime choice of researchers because they have tendency to show higher order of non-linearity. The laser beam interacts with the delocalized π-electrons existing in the organic molecule produce non-linear polarization. The non-linear susceptibility of an organic material would be larger when it has donor-acceptor conjugated molecular systems. Normally amino acids have the tendency to crystallize in a non-centrosymmetric form which is useful for non-linear optical applications. A sequence of second order/third order NLO active materials composed of L-Lysine have been synthesized, such as, L-lysinium picrate, L-Lysine adipate, L-lysine acetate, tetra L-Lysine alanine mono hydrochloride dehydrate [8][9][10][11]. From the coordination chemistry, 5-sulfosalicylicacid (5SSA) is especially an attractive ligand, possessing three potential coordination groups such as OH, . L-Lysinium 5-sulfosalicylate (LL5SS) has been synthesized and grown by solution growth method at room temperature using deionized water as a solvent. The crystal structure of the materials was solved by single crystal X-ray diffraction analysis and it was found that the material has monoclinic system with the space group P21. Fourier transform infrared spectral study was carried out to confirm functional groups present in the crystal. The optical absorption study shows that the crystal is transparent in the entire visible region with a cut-off wavelength of 324 nm. Photoluminescence studies were also carried out to identify the excitation emission of the grown LL5SS crystal. Dielectric study was performed on the single crystal to study the power dissipation of the material in the presence of alternating electric field. Thermal stability has been assessed by thermo gravimetric analysis. Mechanical parameters were calculated. The laser damage threshold value of LL5SS crystal was estimated to be 5.6 GW/cm 2 using a Nd:YAG laser. The Kurtz and Perry powder SHG efficiencies were measured. Non-linear refractive index (n2), non-linear absorption coefficient (β) and third-order non-linear optical susceptibility (χ 3 ) values of LL5SS were found from Z scan technique.

Polymorphs and Transformations of the Solid Forms of Organic Salts of 5-Sulfosalicylic Acid and Isonicotinamide

“…3-Carboxy-4-hydroxybenzenesulfonic acid, also called 5-sulfosalicylic acid ( 5-SSA ) (Scheme ) contains rich functional groups, such as sulfonic, carboxylic, and phenolic groups, thus making it a potential to form extensive hydrogen bonding interactions as proton donors and acceptors. − A range of stoichiometric cocrystals or salts of 5-SSA are studied depending on mono-, di-, or tri-anionic species through deprotonation in self-assembly processes. − In this regard, molecular salts formed by 5-SSA and 4,4′-diaminodiphenylmethane in different stoichiometric ratios are reversibly transformed in the solid state by adding the appropriate amount of one of the corresponding cocrystallizing components upon grinding, and their solid-state fluorescence spectra of corresponding salts are closely related to the degree of anion deprotonation . The salts of 5-SSA and hexamethylenetetramine or benzimidazole further prove the structural transformation of diverse stoichiometric forms in the solid state with the switches between anionic species.…”