168563 20260211123807.0 doi 10.1016/j.molstruc.2026.145493 sideral 148020 ART-2026-148020 eng Sultana, Shabnam Synthesis, characterization, computational study and nonlinear absorption properties of 4-(2-aminomethyl)pyridinium dipicrate 2026 A new picrate salt of nitrogen-rich 4-(2-aminomethyl)pyridinium (PA_4AP) has been successfully crystallized in 2:1 stoichiometry confirming the acid-base proton-transfer. The crystal lattice is marked by H-bond and π-stacking interactions leading to a supramolecular architecture where picrate anions are sandwiched in between the 4-(2-aminomethyl)pyridinium (4AP) cations. Characterization techniques like elemental analysis, PXRD, UV-vis, FT-IR, ESI-MS and 1H/13C-NMR spectroscopy have proved the crystallinity and purity of the complex salt. Then, nonlinear optical (NLO) properties of picric acid (HPA) and PA_4AP has been investigated in DMF solution by irradiating 532 nm Q-switched Nd:YAG nanosecond laser. The open aperture Z-scan curves indicate nonlinear absorption (NLA) behaviour in both the samples. The normalized transmittance (NT) dropped from 100% to 84% and 78% in PA and PA_4AP, respectively, indicating optical limiting (OL) response from both the samples. The NLA coefficient, ß (1.5 × 10−11 m/W) and OL threshold (1.5 × 1013 W/m2) of PA_4AP was found to be higher than the values of HPA, suggesting hydrogen-bonding mediated NLO behaviour marked by reverse saturable absorption mechanisms. DFT calculations performed on optimized HPA and PA_4AP structures in comparison to the crystallographic structure of PA_4AP theoretically predict the smallest HOMO-LUMO gap (1.574 eV), the highest electrophilicity (19.203 eV), and the lowest chemical hardness (0.787 eV) for the crystallographic PA_4AP species compared to the other systems. The experimental results confirm the superior third-order NLO performance of the PA_4AP material driven by hydrogen bond interactions in the supramolecular scaffold. © 2026 Elsevier B.V. info:eu-repo/semantics/closedAccess All rights reserved http://www.europeana.eu/rights/rr-f/ info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Pardos, Jorge Universidad de Zaragoza Zangrando, Ennio Echeverría, Jorge Das, Chandan Ramakrishna, Dileep Manjunatha, K.B. Sanyal, Ria 2013 765 Universidad de Zaragoza Dpto. Química Orgánica Área Química Orgánica 1359 (2026), 145493 J. mol. struct. JOURNAL OF MOLECULAR STRUCTURE 0022-2860 7960733 http://zaguan.unizar.es/record/168563/files/texto_completo.pdf Versión publicada 2461455 http://zaguan.unizar.es/record/168563/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:168563 articulos driver 2026-02-11-10:27:15 ARTICLE