abstract
The dissolution of uracil-a pyrimidine nucleic acid base-in the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C(2)mim][CH3COO]) has been investigated by methods of H-1 and C-13 NMR spectroscopy, H-1-H-1 NOESY NMR spectroscopy, and quantum chemical calculations. The uracil-[C(2)mim][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 (H-1 and C-13 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.
keywords
N-BODY CLUSTERS; CARBOXYLIC-ACIDS; BONDED COMPLEXES; MASS-SPECTROMETRY; INORGANIC SALTS; PHASE-BEHAVIOR; CARBON-DIOXIDE; CELLULOSE; WATER; DENSITY
subject category
Chemistry
authors
Araujo, JMM; Pereiro, AB; Lopes, JNC; Rebelo, LPN; Marrucho, IM
our authors
Isabel Maria Delgado Jana Marrucho Ferreira
Full professorGroups
Projects
Development of New Oxygen Therapeutics using Fluorinated Ionic Liquids (PTDC/EQU-FTT/118800/2010)
PTNMR - Portuguese Nuclear Magnetic Resonance Network (REDE/1517/RMN/2005)
acknowledgements
The financial support from FCT/MEC (Portugal), through grants SFRH/BPD/65981/2009 (J.M.MA.) and SFRH/BPD/84433/2012 (A.B.P.) and a contract under Programa Crencia 2007 (I.M.M.) and through projects PTDC/EQU-EPR/104554/2008, PTDC/QUI-QUI/101794/2008, and PTDC/EQU-FTT/118800/2010 is gratefully acknowledged. The NMR spectrometers are part of the National NMR Network and were purchased in the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005, with funds from POCI 2010 (FEDER) and FCT/MEC.