Investigation of the Hydrogen Bonding Properties of a Series of Monosaccharides in Aqueous Media by 1H NMR and IR Spectroscopy

Abstract

A technique, based on 1 H NMR and IR experiments, to characterise intramolecular hydrogen bonds in aqueous medium in a series of amino, amido and ammonium sugar derivatives has been established. Three groups of molecules, representing amides (4, 5 and 6), amines (7 and 8) and ammonium salts (chlorides 9 and 10, and phosphates 11 and 12), with different relative configurations of their functional groups, have been investigated to assess the effect of the nature and the stereochemistry of these groups on the hydrogen-bonding features of the sugar. The deduced features in water solution are compared to those obtained previously in nonpolar solvents. The phosphate salts of amines 7 and 8 (11 and 12)

Conformational properties of glucose-based disaccharides investigated using molecular dynamics simulations with local elevation umbrella sampling

“…Note that this statement concerning the presumably weak conformational driving force associated with H-bonding 48 pertains to small molecules in an aqueous environment. It may not be applicable to larger systems (e.g., due to H-bonding cooperativity effects [240][241][242]196,[243][244][245][246][247][248][249][250][251][252] in extended chains or reduced local solvation in folded chains) and to other environments (e.g., crystals, fibers, solutions with non-polar solvents, or vacuum). In addition, this hypothesis does not imply that intramolecular H-bonding has no effect on the physico-chemical properties of a specific sugar, because many of these properties are actually defined by a change of environment relative to the bulk aqueous environment at high dilution.…”

Conformation, dynamics, solvation and relative stabilities of selected β-hexopyranoses in water: a molecular dynamics study with the gromos 45A4 force field

“…This is mainly because (i) hydroxyl protons are difficult to detect via NMR spectroscopy 37,[109][110][111][112] (chemical exchange, mutual overlap, overlap with solvent signal); (ii) hydroxyl group vibrations are difficult to characterize via infrared (IR) spectroscopy 110,[113][114][115] (dual hydrogen-bond donoracceptor character, mutual overlap, overlap with solvent bands). Furthermore, X-ray crystallography provides limited reference information in the solid state, because the hydroxyl protons are invisible in these experiments (weak diffraction centers, orientational averaging).…”

“…124,132,133,135,137 Electrostatic effects: Electrostatic effects, mainly intramolecular hydrogen-bonding, are strongly sensitive to the nature and polarity of the solvent. Experimentally, intramolecular hydrogen-bonds in an aqueous environment can be detected only indirectly, for example, via NMR 37,[109][110][111][112]115,[124][125][126][138][139][140][141][142][143][144][145][146][147][148][149] or IR 110,[113][114][115]144,[149][150][151][152][153] spectroscopy. However, most studies to date have investigated model compounds (e.g., monosaccharide analogs) and only provided qualitative information on the existence or absence of a hydrogen-bond.…”

“…However, most studies to date have investigated model compounds (e.g., monosaccharide analogs) and only provided qualitative information on the existence or absence of a hydrogen-bond. Based on these studies, it appears that intramolecular hydrogen-bonds in aldohexopyranoses can be broadly classified into three groups in order of decreasing strength: 110,113,115,154 (i) six-membered hydrogenbonded 'rings' between 1,3-syn-diaxial hydroxyl groups; 101,102,110,114,121,122,125,126,141,[144][145][146][147][148]150,155,156 (ii) five-membered hydrogen-bonded 'rings' between cis-vicinal (axial-equatorial) hydroxyl groups; 121,150 and (iii) five-membered hydrogen-bonded 'rings' between transvicinal (diequatorial) hydroxyl groups. 121,150 Hydrogen-bonding interactions are strong in vacuum or in solvents of low polarity, 121,122,125,126,144,149,155 but probably represent rather weak conformational driving forces in aqueous environment.…”

“…121,150 Hydrogen-bonding interactions are strong in vacuum or in solvents of low polarity, 121,122,125,126,144,149,155 but probably represent rather weak conformational driving forces in aqueous environment. 84,142,146,150,157 For example, although hydrogen-bonds between 1,3-syndiaxial hydroxyl groups in fixed orientations are always observed in water, 110,114,141,148,156 they are not always present when this orientation is conformer-dependent (e.g., when the 'ring' involves one rotatable C-C bond 101,102,144,150 or can only be formed in one chair conformation of a flexible six-membered ring system 121,122,125,126,149,155 ). However, although sometimes questioned, 143 the existence of stable intramolecular hydrogen-bonds for monosaccharide analogs in aqueous solution has been unambiguously evidenced by NMR and IR techniques.…”