Interaction between the π-System of Toluene and the Imidazolium Ring of Ionic Liquids: A Combined NMR and Molecular Simulation Study

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• 作者：Thibaut Gutel ; Catherine C. Santini ; Agí ; lio A. H. Pá ; dua ; Bernard Fenet ; Yves Chauvin ; José ; N. Canongia Lopes ; Franç ; ois Bayard ; Margarida F. Costa Gomes ; Alfonso S. Pensado
• 刊名：Journal of Physical Chemistry B
• 出版年：2009
• 出版时间：January 8, 2009
• 年：2009
• 卷：113
• 期：1
• 页码：170-177
• 全文大小：278K
• 年卷期：v.113,no.1(January 8, 2009)
• ISSN：1520-5207

文摘

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.