Interrogation of Sudan yellow dye imprints on L-Lysine Sulphate (SLLS) semiorganic crystalline form with the assistance of experimental and computational investigations for nonlinear optical applications

The amino acid L lysine, with its unstable protonated α-amino group and deprotonated α-carboxylic acid group, can be mixed with diluted sulphuric acid to create the semiorganic crystal complex L-Lysine Sulphate (LLS). Sudan yellow, an azodye, was used to enhance LLS's chemical and physical properties. The study presents theoretical and experimental results on SLLS single crystals, which belong to the Orthorhombic system with the \({P}_{21}\) $P_{21}$ space group. The Fourier transform infrared emission spectrum of a foundation crystalline form of SLLS was measured using various instruments. The spectrum showed a decrease in the \({NH}^{3 +}\) ${\mathit{NH}}^{3+}$ group's symmetry, increased N–H⋅⋅⋅O hydrogen bonding, and cationic dyes elongation. The lower local symmetry Carbons was present in the \({SO}_{4}\) ${\mathit{SO}}_4$ structure, activating dormant IR modes and dividing degenerate IR modes. The optical absorption of SLLS was determined at 200–800 nm, with a wide absorption maximum in the intense ultraviolet area at around 280 nm. The electrophilicity index (ω) measures the energy reduction caused by the maximum flow of electrons across the source and acceptor. The study concludes that semiorganic crystal SLLS are well suited for nonlinear optical resonators (NLO) applications.