Differentiation of Rubidiated Methyl-d-Glycoside Stereoisomers by Infrared Multiple-Photon Dissociation Spectroscopy in the O鈥揌 and C鈥揌 Stretching Regions

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• 作者：Wright L. Pearson ; III ; Cesar Contreras ; David Powell ; Giel Berden ; Jos Oomens ; Brad Bendiak ; John R. Eyler
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：October 15, 2015
• 年：2015
• 卷：119
• 期：41
• 页码：12970-12981
• 全文大小：622K
• ISSN：1520-5207

文摘

Four isomeric sugar methylglycosides (伪- and 尾-d-gluco- and galactopyranosides) were evaluated as rubidium cation coordination adducts in the gas phase using variable-wavelength multiple-photon dissociation in the range from 2750 to 3750 cm^鈥?. The adducts dissociated following photon absorption to yield neutral sugars and the rubidium cation, resulting in infrared 鈥渁ction鈥?spectra. Well-resolved hydroxyl stretching bands clearly differentiate stereoisomers that vary solely in their asymmetry at single carbons. Density functional theory calculations of the lowest-energy gas-phase complexes indicate that rubidium coordinates with lone pairs of oxygen atoms as either bi- or tridentate complexes and that more than one positional coordination isomer could adequately account for most of the O鈥揌 stretch frequencies observed for each methylglycoside.