Hydrogen-Bonding and the Dissolution Mechanism of Uracil in an Acetate Ionic Liquid: New Insights from NMR Spectroscopy and Quantum Chemical Calculations

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• 作者：Jo茫o M. M. Ara煤jo ; Ana B. Pereiro ; Jos茅 N. Canongia Lopes ; Lu铆s P. N. Rebelo ; Isabel M. Marrucho
• 刊名：The Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：April 18, 2013
• 年：2013
• 卷：117
• 期：15
• 页码：4109-4120
• 全文大小：615K
• 年卷期：v.117,no.15(April 18, 2013)
• ISSN：1520-5207

文摘

The dissolution of uracil鈥揳 pyrimidine nucleic acid base鈥搃n the ionic liquid 1-ethyl-3-methylimidazolium acetate ([Cb>2b>mim][CHb>3b>COO]) has been investigated by methods of ¹H and ¹³C NMR spectroscopy, ¹H鈥?sup>1H NOESY NMR spectroscopy, and quantum chemical calculations. The uracil鈥揫Cb>2b>mim][CHb>3b>COO] interactions that define the dissolution mechanism comprise the hydrogen bonds between the oxygen atoms of the acetate anion and the hydrogen atoms of the N1鈥揌 and N3鈥揌 groups of uracil and also the hydrogen bonds between the most acidic aromatic hydrogen atom (H2) of the imidazolium cation and the oxygen atoms of the carbonyl groups of uracil. The bifunctional solvation nature of the ionic liquid can be inferred from the presence of interactions between both ions of the ionic liquid and the uracil molecule. The location of such interaction sites was revealed using NMR data (¹H and ¹³C chemical shifts both in the IL and in the uracil molecule), complemented by DFT calculations. NOESY experiments provided additional evidence concerning the cation鈥搖racil interactions.