Synthesis, characterization, antimicrobial activity and <i>in silico</i> study of pyridinium based ionic liquids

A series of twenty-one pyridinium-based ionic liquids (ILs) was synthesized and thoroughly characterized using FTIR, NMR, UV-Vis spectroscopy, and melting point analysis. The ILs' antibacterial activity was assessed against <i>Aspergillus niger</i> and a panel of bacteria, both Gram-positive and Gram-negative. Notable antibacterial and antifungal properties were demonstrated by IL-10, IL-11, and IL-14 specifically. Several ILs also demonstrated effective Brønsted acidic catalysis for the Mannich process under mild, solvent-free circumstances. The biological activity of IL-19 and IL-21 was found to be correlated with their significant binding affinities to microbial protein targets, as demonstrated by molecular docking experiments. Selected ILs, especially IL-05 and IL-21, were found to be drug-like and biosafe based on ADMET and toxicity predictions. These results highlight the pyridinium-based ILs' multipurpose potential as green catalysts and antibacterial agents for sustainable synthetic applications.