Dicationic Ionic Liquids with an Indole-3-butyrate Anion – Plant Growth Stimulation and Ecotoxicological Evaluations

Due to the poor water solubility of indole-3-butyric acid (IBA), adding appropriate adjuvants to this compound during application is essential. The physicochemical properties of plant growth regulators can be easily modified by transforming them into ionic liquids. In this research, IBA was converted into an anion and conjugated with a bis-ammonium cation to form novel dicationic ionic liquids (DILs). The purpose of obtaining these new DILs was to improve the biological activity and determine the effects of the modifications on the stability and persistence of soil microorganisms. The synthesis method enabled the designed DILs to be obtained with yields above 85%. The surface tension and chemical stability results indicated that these properties could be optimized by selecting appropriate cations. A solubility study indicated that the transformation of IBA into DILs improved the solubility of the active ingredient in water. Analysis of the growth-stimulating activity of the DILs on corn showed that the application of DILs significantly increased the fresh and dry cobs’ weight compared to control plants. An experiment evaluating the effects of DILs on soil microorganisms showed that high concentrations of IBA anion inhibited bacterial growth and could have distorted cell metabolism. The DILs presented in this research may be potential alternatives to commercially used formulations.