Journal article
Doubly ionic hydrogen bond interactions within the choline chloride-urea deep eutectic solvent
Physical chemistry chemical physics : PCCP, Vol.18(27), pp.18145-18160
07/21/2016
Handle:
https://hdl.handle.net/2376/108165
PMID: 27328990
Abstract
Deep eutectic solvents (DESs) are exemplars of systems with the ability to form neutral, ionic and doubly ionic H-bonds. Herein, the pairwise interactions of the constituent components of the choline chloride-urea DES are examined. Evidence is found for a tripodal CHCl doubly ionic H-bond motif. Moreover it is found that the covalency of doubly ionic H-bonds can be greater than, or comparable with, neutral and ionic examples. In contrast to many traditional solvents, an "alphabet soup" of many different types of H-bond (OHO[double bond, length as m-dash]C, NHO[double bond, length as m-dash]C, OHCl, NHCl, OHNH, CHCl, CHO[double bond, length as m-dash]C, NHOH and NHNH) can form. These H-bonds exhibit substantial flexibility in terms of number and strength. It is anticipated that H-bonding will have a significant impact on the entropy of the system and thus could play an important role in the formation of the eutectic. The 2 : 1 urea : choline-chloride eutectic point of this DES is often associated with the formation of a [Cl(urea)2](-) complexed anion. However, urea is found to form a H-bonded urea[choline](+) complexed cation that is energetically competitive with [Cl(urea)2](-). The negative charge on [Cl(urea)2](-) is found to remain localised on the chloride, moreover, the urea[choline](+) complexed cation forms the strongest H-bond studied here. Thus, there is potential to consider a urea[choline](+)·urea[Cl](-) interaction.
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Details
- Title
- Doubly ionic hydrogen bond interactions within the choline chloride-urea deep eutectic solvent
- Creators
- Claire R Ashworth - Department of Chemistry, Imperial College London, London, SW7 2AZ, UK. p.hunt@imperial.ac.ukRichard P MatthewsTom WeltonPatricia A Hunt
- Publication Details
- Physical chemistry chemical physics : PCCP, Vol.18(27), pp.18145-18160
- Academic Unit
- Molecular Biosciences, School of
- Publisher
- England
- Identifiers
- 99900546901001842
- Language
- English
- Resource Type
- Journal article