title: Interaction between the pi-system of toluene and the imidazolium ring of ionic liquids: a combined NMR and molecular simulation study.
abstract: The solute-solvent interactions and the site-site distances between toluene and ionic liquids (ILs) 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide [BMMIm][NTf2] and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIm][NTf2] at various molar ratios were determined by NMR experiments (1D NMR, rotating-frame Overhauser effect spectroscopy (ROESY)) and by molecular simulation using an atomistic force field. The difference in behavior of toluene in these ILs has been related to the presence of H-bonding between the C2-H and the anion in [BMIm][NTf2] generating a stronger association (>20 kJ.mol-1) than in the case of [BMMIm][NTf2]. Consequently, toluene cannot cleave this H-bond in [BMIm][NTf2] which remains in large aggregates of ionic pairs. However, toluene penetrates the less strongly bonded network of [BMMIm][NTf2] and interacts with [BMMIm] cations.
authors.affiliation: Université de Lyon, Institut de Chimie de Lyon, Equipe Chimie Organométallique de Surface, France.
authors.forename: Thibaut
authors.initials: T
authors.lastname: Gutel
authors.forename: Catherine C
authors.initials: CC
authors.lastname: Santini
authors.forename: Agilio A H
authors.initials: AA
authors.lastname: Pádua
authors.forename: Bernard
authors.initials: B
authors.lastname: Fenet
authors.forename: Yves
authors.initials: Y
authors.lastname: Chauvin
authors.forename: José N
authors.initials: JN
authors.lastname: Canongia Lopes
authors.forename: Francois
authors.initials: F
authors.lastname: Bayard
authors.forename: Margarida F
authors.initials: MF
authors.lastname: Costa Gomes
authors.forename: Alfonso
authors.initials: A
authors.lastname: Pensado