Structure and interaction properties of MBIL [Bmim][FeCl4] and methanol: A combined FTIR and simulation study

Abstract Ionic liquids (ILs) are a kind of novel solvents of which some are green with many possible applications, e.g., as efficient catalyst. Structures and properties of ILs are determined by coulomb and van der Waals interactions and also by hydrogen-bonding between cations and anions. Particularly, metal-based ionic liquids (MBILs) exhibit excellent catalytic properties in the lignin conversions due to their superiority in paramagnetism, Lewis acidity, and electrochemistry. Nevertheless, the structural properties of MBILs are scarcely understood. Therefore, the hydrogen-bonding interactions between [Bmim][FeCl4] and methanol at different concentration were studied in this work by using excess infrared spectroscopy, density functional theory (DFT) and molecular dynamics (MD) simulations. The results showed that hydrogen-bonding interactions between cations and anions of [Bmim][FeCl4] were gradually weakened with increasing the concentration of methanol. However, cations and anions tended to bind together because of the original stable hydrogen-bonding network when the mole fraction of methanol was