Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2780-157 Oeiras, Portugal.
J Phys Chem B. 2013 Apr 18;117(15):4109-20. doi: 10.1021/jp400749j. Epub 2013 Apr 4.
The dissolution of uracil-a pyrimidine nucleic acid base-in the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][CH3COO]) has been investigated by methods of (1)H and (13)C NMR spectroscopy, (1)H-(1)H NOESY NMR spectroscopy, and quantum chemical calculations. The uracil-[C2mim][CH3COO] 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-H and N3-H 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 ((1)H and (13)C chemical shifts both in the IL and in the uracil molecule), complemented by DFT calculations. NOESY experiments provided additional evidence concerning the cation-uracil interactions.
已经通过（1）H 和（13）C NMR 光谱、（1）H-（1）H NOESY NMR 光谱和量子化学计算方法研究了嘧啶核酸碱基尿嘧啶在离子液体 1-乙基-3-甲基咪唑乙酸盐 ([C2mim][CH3COO]) 中的溶解情况。定义溶解机制的尿嘧啶-[C2mim][CH3COO]相互作用包括乙酸阴离子的氧原子与尿嘧啶的 N1-H 和 N3-H 基团的氢原子之间的氢键，以及最酸性芳环氢原子（H2）的氢键咪唑阳离子和尿嘧啶羰基的氧原子。离子液体的双功能溶剂化性质可以从离子液体的两个离子与尿嘧啶分子之间的相互作用推断出来。这些相互作用位点的位置是通过 NMR 数据（离子液体和尿嘧啶分子中的（1）H 和（13）C 化学位移）揭示的，并辅以 DFT 计算。NOESY 实验提供了关于阳离子-尿嘧啶相互作用的额外证据。
