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Hydroxy protons in structural analysis of carbohydrates by NMR spectroscopy and computational methods

Bekiroglu, Somer (2003). Hydroxy protons in structural analysis of carbohydrates by NMR spectroscopy and computational methods. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae. Agraria, 1401-6249 ; 391
ISBN 91-576-6442-0
[Doctoral thesis]

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Abstract

This thesis describes the use of hydroxy protons in structural analysis of carbohydrates in aqueous solution by NMR spectroscopy. For aqueous solutions of carbohydrates, using H₂O as the solvent of choice instead of D₂O makes it possible to observe exchangeable protons provided that the proton exchange with bulk water is slow enough. Thus, additional data from exchangeable protons can be acquired in terms of chemical shifts, vicinal coupling constants, temperature coefficients, exchange rates, and NOEs. The application of the method on the Lewis b, X, and Y oligosaccharides supplied further information about the rigidities of the molecules. Regarding the chemical shift differences, extent of interaction with bulk water molecules and being located around amphiphilic regions were anticipated to play role on magnetic shieldings of hydroxy protons (Articles I-II). The hydrogen bonds between O(2)H and O(3)H groups on adjacent glucose units in CDs were proved to exist in water solution (Article III), as they had been reported in solid state and DMSO solutions. A weak and transient interaction was also observed between O(2')H and O(3)H in maltose. Using hydroxy protons, the study of intermolecular interactions on the cyclodextrin complexes proved to be useful in providing structural information as chemical shift, temperature coefficient and line-shape of the hydroxy proton signals. The intermolecular interactions between carbohydrates and nucleotides as revealed by IR studies could not be detected by NMR spectroscopy (Article IV). However, a drastic improvement in the intensity and line-shape of the hydroxy signals from saccharides were encountered upon addition of small amount of purine nucleos(t)ides and nucleobases. If the reason for the observed upfield and downfield shifts (positive and negative Δδ values) is contemplated, hydration turns out to be the keyword (Article V). When the hydration of a hydroxy proton is hampered by either interactions with acetal oxygens or structural formations (steric effects or perturbed water interactions in amphiphilic regions), the chemical shift of that proton reads an upfield-shifted value in comparison with the hydroxy proton in the corresponding monomeric unit. Likewise, provided that the hydration state is kept the same, a hydroxy proton becomes deshielded when it forms hydrogen bond interaction with another hydroxy group.

Authors/Creators:Bekiroglu, Somer
Title:Hydroxy protons in structural analysis of carbohydrates by NMR spectroscopy and computational methods
Year of publishing :April 2003
Volume:391
Number of Pages:53
Papers/manuscripts:
NumberReferences
ALLI. Hydroxy Protons in Conformational Study of a Lewis b Tetrasaccharide Derivative in Aqueous Solution by NMR Spectroscopy S. Bekiroglu, C. Sandström, T. Norberg, and L. Kenne, Carbohydrate Research, 328 (2000) 409-418 II. Structural ¹H NMR Study of Lewis X and Y Oligosaccharides in Aqueous Solution Using Hydroxy Protons Somer Bekiroglu, Lennart Kenne, and Corine Sandström, article in manuscript III. ¹H NMR Studies of Maltose, Maltoheptaose, α -, β -, and γ -Cyclodextrins, and Complexes in Aqueous Solutions with Hydroxy Protons as Structural Probes Somer Bekiroglu, Lennart Kenne, and Corine Sandström, Journal of Organic Chemistry, 68 (2003) 1671-1678 IV. The Effect of Nucleoside Addition on the 1 H NMR Spectra of Saccharides Somer Bekiroglu, Ianric Ivarsson, Lennart Kenne, and Corine Sandström, submitted article V. The Effect of Hydration on the NMR Chemical Shifts of Hydroxy Protons in Carbohydrates Somer Bekiroglu, Anders Sandström, Lennart Kenne, Corine Sandström, submitted article
Place of Publication:Uppsala
ISBN for printed version:91-576-6442-0
ISSN:1401-6249
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:X Agricola extesions > X50 Chemistry
Subjects:Not in use, please see Agris categories
Agrovoc terms:hydration, nmr spectroscopy, dextrins, nucleosides
Keywords:Hydroxy protons, NMR, ab initio, NMR, chemical shift, hydrogen bond, hydration, interaction, conformation, Lewis b, Lewis X, Lewis Y oligosaccharides, cyclodextrins, nucleoside
URN:NBN:urn:nbn:se:slu:epsilon-35
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-35
ID Code:244
Department:(NL, NJ) > Dept. of Chemistry (until 131231)
Deposited By: Somer Bekiroglu
Deposited On:25 Apr 2003 00:00
Metadata Last Modified:02 Dec 2014 10:03

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