Insights into the local structures of water in 1-butyl-3-methylimidazolium iodide

Abstract Recently, the presence of cavities in ionic liquids (ILs), which affects the solubility of solute molecules such as CO2, has been demonstrated. With the aim of gaining more insight into the interactions between the IL and guest water molecules, the changes experienced upon addition of water molecules to an IL have been monitored by Raman spectroscopy. This study focuses on how the difference in the nanoheterogeneous structures of two ILs, 1-butyl-3-methylimidazolium iodide (abbreviated as [bmim][I]) and 1-butyl-3-methylimidazolium tetrafluoroborate (abbreviated as [bmim][BF4]) influences the local structure of water embedded in the ILs. The evolution of local water clusters formed in the ILs is compared. Then, the connections between microscopic and macroscopic properties were reviewed.