Water assisted stability of carbene: Cyclic voltammetric investigation of 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid
In this work, we report electrochemical studies on the imidazolium-based ionic liquids with an objective to explore the possibility of carbene formation in their dilute aqueous solutions. Conventionally, water plays detrimental role during the investigations, involving ionic liquids. Such a role of water has been investigated on the electrochemical studies in aqueous ionic liquid solutions. There are diffused opinions about the influence of water on physico-chemical behaviour of ionic liquids that needs to have in-depth understanding. In this regard, we attempted to explore the electrochemical performance of the ionic liquids in water as a solvent and the influence of water on ionic liquids were judged through feasibility and stability of carbene formed in aqueous solution of the imidazolium-based ionic liquids. The electrochemical investigation on aqueous solution of 1-ethyl-3-methylimidazoulium ethylsulphate ([EMIM][EtSO4]) displayed the redox couple. The detailed invesigations suggest the reduction of imidazolium cation at C2 position and subsequent formation of carbene. Furthermore, anodic peak was found to be associated with the oxidation of carbene. Coulommetric process associated with anodic peak indicates two electron oxidation of carbene. Stability of carbene in water was evaluated through use of different protic and aprotic solvents. Hydrogen bond forming ability of carbene with water signs to be responsible for its improved stability in water.