Inclusion Complexes of Ionic Liquids and Cyclodextrins: Are They Formed in the Gas Phase?
authors Fernandes, AM; Schroder, B; Barata, T; Freire, MG; Coutinho, JAP
nationality International
journal JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
author keywords Ionic liquids; Cyclodextrin; Inclusion; Electrospray-ionization; Collision-induced-dissociation; Electronic-structure calculations
keywords ELECTROSPRAY MASS-SPECTROMETRY; HOST-GUEST COMPLEXATION; BETA-CYCLODEXTRIN; SUPRAMOLECULAR CHEMISTRY; MOLECULAR RECOGNITION; ALPHA-CYCLODEXTRIN; AQUEOUS-SOLUTIONS; NONCOVALENT INTERACTIONS; INORGANIC ANIONS; WATER
abstract The interaction of imidazolium-based ionic liquids with alpha- and beta-cyclodextrins was investigated by electrospray ionization mass spectrometry with variable collision induced dissociation energy and quantum chemical gas-phase calculations. The center-of-mass energy at which 50 % of a precursor ion decomposes (E-cm,E-1/2) was determined for the isolated [cyclodextrin + cation](+) or [cyclodextrin + anion](-) adduct ions of imidazolium-based ionic liquids with different alkyl chain lengths combined with a large set of anions, such as chloride, bromide, bis(trifluoromethylsulfonyl)imide, tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, methanesulfonate, dicyanamide, and hydrogensulfate. Moreover, both symmetric and asymmetric imidazolium cationic cores were evaluated. The relative interaction energies in the adduct ions were interpreted in terms of the influence of cation/anion structures and their inherent properties, such as hydrophobicity and hydrogen bond accepting ability, in the complexation process with the cyclodextrins. The trends observed in the mass spectral data together with quantum-chemical calculations suggest that in the gas phase, cations and anions will preferentially interact with the lower or upper rim of the cyclodextrin, respectively, as opposed to what has been reported in condensed phase where the formation of an inclusion complex between ionic liquid and cyclodextrin is assumed.
publisher SPRINGER
issn 1044-0305
year published 2014
volume 25
issue 5
beginning page 852
ending page 860
digital object identifier (doi) 10.1007/s13361-013-0820-9
web of science category Biochemical Research Methods; Chemistry, Analytical; Chemistry, Physical; Spectroscopy
subject category Biochemistry & Molecular Biology; Chemistry; Spectroscopy
unique article identifier WOS:000334513600018
link 24584889

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