l-Glycine and l-leucine derived multifunctional ionic liquids for potential antibacterial applications: in-vitro and in-silico studies

Ionic liquids (ILs) have gained significant attention among material scientists for their versatile properties. Amino acid-based ionic liquids (AAILs) have the potential to be tailored for desired physicochemical properties due to their structural adaptability and unique attributes. Twenty-four distinct ILs were synthesized, containing multifunctional cations viz. 1-octyl pyridinium, 1-octyl-3-methylimidazolium, 1,3-dioctylimidazolium, Di-octyldi-butylammonium, Tetraoctylphosphonium, N, N, N', N'-Tetrakis-(2-hydroxyethyl)dioctyldiammonium, 1H-1,2,3-triazole, and 1-octyl-1,8-diazabicyclo(5.4.0)undec-7-enium, each with varied chain lengths. Whereas, bromide, glycinate, and leucinate were incorporated as counter-anionic species. These distinct ILs were characterized by FT-IR, ¹H, and ¹³C-NMR spectroscopies and were systematically evaluated for anti-bacterial efficacy by agar well diffusion method against six potent bacterial strains. Both gram-positive as well as gram-negative types, namely Shigella dysenteria, Shigella boyydii, Staphylococcus aureus, Carbapenem-resistant Enterobacter baumannii, Escherichia coli, and Klebsiella pneumonia were tested. Remarkably strong antibacterial performance was observed across most of the synthesized ILs, particularly notable against gram-negative strains, signifying their potential as antibacterial agents. The good antibacterial performance of ILs was also validated by molecular docking, and a good agreement was found between computational and experimental studies. These findings open new avenues for the development of effective antibacterial agents based on ILs in infection control for individuals with disabilities.