Developing New Sustainable Pyridinium Ionic Liquids: From Reactivity Studies to Mechanism-Based Activity Predictions

Abstract

Recently, pyridinium-based ionic liquids have been received great attention thanks to their unique features, such as low melting points, low volatility, high thermal stability, and moderate solvation properties. In the present work, for the first time, three pyridinium-based ionic liquids 1-(2-(isopentyloxy)-2-oxoethyl)pyridin-1-ium chloride, 1-(2-(hexyloxy)-2-oxoethyl)pyridin-1-ium chloride, and 1-(2-(benzyloxy)-2-oxoethyl)pyridin-1-ium chloride were synthesized by simply reacting pyridine with esters of monochloroacetic acid. The biological activities of as-prepared compounds were evaluated experimentally through plant growth promotion, herbicidal, and insecticidal assays The biological test results show thate benzyloxy derivative stimulated wheat and cucumber growth over 20% at lower doses. The isopentyloxy compound was the most effective herbicide, reducing root/stem growth by >80%.. To support experimental data, the computational methods including DFT calculations, molecular docking and druglikeness prediction were also applied. It was found that the benzyloxy salt had the highest predicted binding affinities and druglikeness and yield was for pure salt production is in 78-86%. An integrated experimental-computational approach provided insights into structure-activity relationships and mechanisms of action. The results showed the biological activity depends on substituent chain length/structure, influencing lipophilicity and membrane/target interactions. The findings support further development of optimized pyridinium ionic liquids as natural active agents for agriculture and pharmaceutical applications. These ionic salts are suggested as potential agent in agricultural, pharmaceutical and industrial application.