Synthesis, crystal structure, Hirshfeld surface analysis, optical properties, antibacterial activity, and DFT calculations of benzyl-4-aminopyridinium picrate

In this study, a new organic crystal with functions of optical properties and bactericidal activity, benzyl-4-aminopyridinium picrate [Bz-4-NH₂Py][PIC] (<b>1</b>), was synthesized by the slow evaporation solution growth technology and characterized by single-crystal and X-ray diffraction, IR spectrum, Hirshfeld surface analysis, and electronic absorption spectrum. The compound crystallized in the monoclinic space group <i>P</i>2₁/<i>c</i>. Thermal analysis revealed that the material was stable up to 261.8°C. The value of the first hyperpolarizability (<i>β</i>_tot) of the crystal was 27.7 times that of the standard KDP crystal, demonstrating superior nonlinear optical properties. Furthermore, the compound manifested excellent antibacterial activity against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>. A new picrate salt with a substituted 4-aminopyridinium cation was synthesized and characterized.The intermolecular interactions in the crystal were quantified and analyzed using Hirshfeld surface analysis.The HOMO-LUMO energy gap explains the charge transfer interactions in the molecule.The nonlinear optical properties were studied using DFT calculation.The as-synthesized salt exhibits good antibacterial activities against <i>S. aureus</i> and <i>E. coli</i>. A new picrate salt with a substituted 4-aminopyridinium cation was synthesized and characterized. The intermolecular interactions in the crystal were quantified and analyzed using Hirshfeld surface analysis. The HOMO-LUMO energy gap explains the charge transfer interactions in the molecule. The nonlinear optical properties were studied using DFT calculation. The as-synthesized salt exhibits good antibacterial activities against <i>S. aureus</i> and <i>E. coli</i>.