Crystal growth, spectroscopic investigation and z-scan analysis of novelly synthesized NLO active bis(2-amino-4,6-dimethoxypyrimidinium) 5-sulfosalicylate single crystal

A novel organic single crystal bis(2-amino-4,6-dimethoxypyrimidinium) 5-sulfosalicylate (B2AD5SSA) was synthesized and examined through the FT-Raman, UV–Vis, single crystal X-ray diffraction and FT-IR investigations. The B2AD5SSA crystal affiliated to the triclinic with centrosymmetric space group P-1 was validated through single crystal X-ray diffraction (SXRD). The B3LYP/LANL2DZ basis set was employed in the density functional theory (DFT) for the quantum chemical calculations. The natural bond orbital (NBO) analysis provides a detailed study of the intermolecular interactions and stability of the B2AD5SSA molecule. To highlight the existence of different functional groups in the B2AD5SSA molecule, the FT-Raman and FT-IR spectral analysis were carried out. A graphical representation of the B2AD5SSA molecule’s charge distribution was provided by the frontier molecular orbital (FMO) and molecular electrostatic potential (MEP). The energy gap of B2AD5SSA was determined to be 5.33 eV. Reduced density gradient (RDG), interaction region indicator (IRI) and atoms in molecule (AIM) analyses were used to explore the N–H…O and O–H…O interaction within the B2AD5SSA molecule. Using UV–visible spectral analysis, the transmittance spectra and band gap energy of the title compound were measured and examined. Fluorescence spectral analysis has been used to examine the emission spectra at 407 nm, which was advantageous for the development of violet light-emitting devices. By employing TG–DTA analysis, the thermal stability of the B2AD5SSA crystal was calculated to be 192 °C. The hole-electron analysis was performed to demonstrate charge transfer within the molecule. Hirshfeld surface analysis and a two-dimensional fingerprint plot were used to examine the molecular surface contours and intermolecular interactions. The NLO activity of the B2AD5SSA molecule was investigated both theoretically and experimentally using the DFT and Z-scan techniques. The first-order hyperpolarizability (β) and third order susceptibility (χ⁽³⁾) of the B2AD5SSA was found to be 70.51*10^–30 esu and 6.58*10^–6 esu. While comparing the results of UV–visible, NLO, FMO and Z-scan with 5-sulfosalicylate based compounds, the compound B2AD5SSA shows strong NLO activity.