Manipulating Solute Nucleophilicity with Room Temperature Ionic Liquids

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• 作者：Lorna Crowhurst ; N. Llewellyn Lancaster ; Juan M. Pé ; rez Arlandis ; and Tom Welton
• 刊名：Journal of the American Chemical Society
• 出版年：2004
• 出版时间：September 22, 2004
• 年：2004
• 卷：126
• 期：37
• 页码：11549 - 11555
• 全文大小：89K
• 年卷期：v.126,no.37(September 22, 2004)
• ISSN：1520-5126

文摘

In this work we report the effect of ionic liquids on a class of charge-neutral nucleophiles. Wehave studied the reactions of ⁿbutylamine, di-ⁿbutylamine, and tri-ⁿbutylamine with methyl p-nitrobenzenesulfonate in [bmpy][N(Tf)₂], [bmpy][OTf], and [bmim][OTf] (bmpy = 1-butyl-1-methylpyrrolidinium; bmim =1-butyl-3-methylimidazolium) and compared their reactivities, k₂, to those for the same reactions in themolecular solvents dichloromethane and acetonitrile. It was shown that all of the amines are morenucleophilic in the ionic liquids than in the molecular solvents studied in this work. Comparison is alsomade with the effect of ionic liquids on the reactivity of chloride ions, which are deactivated in ionic liquids.The Eyring activation parameters revealed that changes in the activation entropies are largely responsiblefor the effects seen. This can be explained in part by the differing hydrogen-bonding properties, as shownby the Kamlet-Taft solvent parameters, of each of these solvents and the formation of hydrogen bondsbetween the solvents and the nucleophiles.