Synthesis, DNA-binding study and antioxidant assay of novel protic ionic liquids: Experimental and computational approaches

Abstract A series of five AMPS-based new ionic liquids (ILs) paired with different cations (thiazolium, ammonium, morpholinium, pyrrolidinium and iminium) has been synthesized and characterized by spectroscopic analysis. 3-Benzyl-5-(2-hydroxyethyl)-4-thiazolium [bnthia], (vinylbenzyl)trimethylammonium [vbn], morpholinium [mrph], 1-butyl-1-methylpyrrolidinium [pyrli] and (chloromethylene)dimethyl iminium [diMeimi] were used as cation moieties. DNA binding interactions, antioxidant assay and DFT studies have further been performed. The DNA binding analysis revealed that all the investigated ILs were able to electrostatically interact with DNA. None of the IL could intercalate into DNA. The DFT calculations predicted that [bnthia][AMPS] and [vbn][AMPS] may stabilize incoming electrons in their LUMO orbitals and can be radical scavenger. This prediction was supported by antioxidant assay using UV–Vis spectroscopy and cyclic voltammetry where DPPH radical scavenging by [bnthia][AMPS] and [vbn][AMPS] confirmed the DFT prediction. However, rest of the ILs did not scavenge DPPH free radicals.