Crystal growth, structural, vibrational, topological and z-scan analysis of novel NLO active bis (2-amino-3-methylpyridinium) 5-sulfosalicylate monohydrate single crystal: Experimental and Computational approach

In this work bis (2-amino-3-methylpyridinium) 5-sulfosalicylate monohydrate (2AM5SSA), a new organic NLO active compound was synthesized by slow evaporation technique and subsequently analyzed using X-ray crystallography, UV-Vis, FTIR and FT-Raman spectral analysis. The 2AM5SSA comes under the centrosymmetric space group P-1 of the triclinic crystal system as verified by single crystal X-ray (SXRD) diffraction. Density functional theory (DFT) with B3LYP/6-31 G (d, p) basis set was deployed to execute the quantum chemical computation. Both FTIR and FT-Raman spectral analysis, authenticate the existence of several functional groups and vibrational modes. NBO study has provided information about the stability and intermolecular interactions of the 2AM5SSA. The charge distribution of the title molecule is graphically visualized using the natural population analysis (NPA) and frontier molecular (FMO) analysis. Through reduced density gradient (RDG) and interaction region indicator (IRI) analyses, the molecule's steric effect and van der Waals interaction were determined. To determine the potential sites for nucleophilic and electrophilic attack, the Fukui analysis was performed. To examine the intermolecular interactions, the Hirshfeld surface analysis was executed. The optical features and band gap energy of 2AM5SSA were ascertained using the UV-Vis optical spectrum. TG/DTA analysis was used to determine the thermal stability of the grown crystal. Scanning electron (SEM) microscopy was employed to determine the grown crystal's surface morphology. Through fluorescence spectral analysis, the green emission of the 2AM5SSA single crystal at 544 nm was detected. Both experimental and theoretical analysis of the NLO property of the 2AM5SSA molecule was performed via z-scan and DFT techniques. Z-scan, NLO, UV-Vis and HOMO-LUMO values were compared with other related 5-sulfosalicylic acid based NLO active compounds that have previously been investigated.