One-pot synthesis of aprotic ionic liquid through solvent-free alkylation of an organic superbase

Abstract Synthesis of a novel aprotic ionic liquid (IL), hexyl-1,8-diazabicyclo[5.4.0]-undec-7-ene-8-ium hydroxide ([C6DBU]OH) was carried out by solvent-free alkylation of a base, 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU) followed by anion metathesis. The formation of [C6DBU]OH was traced with a thermogravimetric analysis. The chemical structure of [C6DBU]OH IL synthesized was determined with Fourier-transform infrared, 1H NMR and 13C NMR spectroscopy. The experimental results concerning the evidence of formation and identification of chemical structure of [C6DBU]OH were supported by density functional theory which demonstrates that multifaceted interionic C–H∙∙∙O hydrogen bonds by the constituent ions of the novel IL stabilize [C6DBU]OH.