Direct evidence for the ring opening of monosaccharide anions in the gas phase: photodissociation of aldohexoses and aldohexoses derived from disaccharides using variable-wavelength infrared irradiation in the carbonyl stretch region

TitleDirect evidence for the ring opening of monosaccharide anions in the gas phase: photodissociation of aldohexoses and aldohexoses derived from disaccharides using variable-wavelength infrared irradiation in the carbonyl stretch region
Publication TypeJournal Article
Year of Publication2011
AuthorsD.J Brown, S.E Stefan, G. Berden, J.D Steill, J. Oomens, J.R Eyler, B. Bendiak
JournalCarbohydrate Research
Volume346
Issue15
Pagination2469-2481
Date PublishedNov
Type of ArticleArticle
ISBN Number0008-6215
KeywordsANOMERIC CONFIGURATION, C-13 NMR, Carbonyl group, DETERMINATION, DISACCHARIDES, ELECTROSPRAY-IONIZATION, FRAGMENT ION, free-electron laser, infrared, LINKAGE POSITION, LITHIUM-CATIONIZED, Mass spectrometry, Monosaccharides, MULTIPHOTON DISSOCIATION, MULTIPLE-PHOTON DISSOCIATION, photodissociation, PYRANOSE-FURANOSE INTERCONVERSIONS, STEREOCHEMISTRY, TANDEM MASS-SPECTROMETRY
Abstract

All eight D-aldohexoses and aldohexoses derived from the non-reducing end of disaccharides were investigated by variable-wavelength infrared multiple-photon dissociation (IRMPD) as anions in the negative-ion mode. Spectroscopic evidence supports the existence of a relatively abundant open-chain configuration of the anions in the gas phase, based on the observation of a significant carbonyl absorption band near 1710 cm(-1). The abundance of the open-chain configuration of the aldohexose anions was approximately 1000-fold or greater than that of the neutral sugars in aqueous solution. This provides an explanation as to why it has not been possible to discriminate the anomeric configuration of aldohexose anions in the gas phase when derived from the non-reducing sugar of a disaccharide. Evidence from photodissociation spectra also indicates that the different aldohexoses yield product ions with maximal abundances at different wavelengths, and that the carbonyl stretch region is useful for differentiation of sugar stereochemistries. Quantum-chemical calculations indicate relatively low energy barriers to intramolecular proton transfer between hydroxyl groups and adjacent alkoxy sites located on open-chain sugar anions, suggesting that an ensemble of alkoxy charge locations contributes to their observed photodissociation spectra. Ring opening of monosaccharide anions and interconversion among configurations is an inherent property of the ions themselves and occurs in vacuo independent of solvent participation. (C) 2011 Elsevier Ltd. All rights reserved.

DOI10.1016/j.carres.2011.06.018
Division

GUTHz

Department

FELIX

PID

16a9c5f7499e32e892a3f9d14254c4aa

Alternate TitleCarbohydr. Res.

Go back one page.