title: An NMR investigation of putative interresidue H-bonding in methyl alpha-cellobioside in solution.
abstract: Methyl alpha-cellobioside (methyl beta-D-glucopyranosyl-(1-->4)-alpha-D-glucopyranoside) was labeled with (13)C at C4' for use in NMR studies in DMSO-d(6) solvent to attempt the detection of a trans-H-bond J-coupling ((3h)J(CCOH)) between C4' and OH3. Analysis of the OH3 signal at 600 MHz revealed only the presence of two homonuclear J-couplings: (3)J(H3,OH3) and a smaller, longer range J(HH). No evidence for (3h)J(C4',OH3) was found. The longer range J(HH) was traced to (4)J(H4,OH3) based on 2D (1)H-(1)H COSY data and inspection of the H2 and H4 signal lineshapes. A limited set of DFT calculations was performed on a methyl cellobioside mimic to evaluate the structural dependencies of (4)J(H2,O3H) and (4)J(H4,O3H) on the H3-C3-O3-H torsion angle. Computed couplings range from about -0.7 to about +1.1 Hz, with maximal values observed when the C-H and O-H bonds are roughly diaxial.
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, United States.
authors.forename: Wenhui
authors.initials: W
authors.lastname: Zhang
authors.forename: Hongqiu
authors.initials: H
authors.lastname: Zhao
authors.forename: Ian
authors.initials: I
authors.lastname: Carmichael
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Serianni
mesh_terms: D002247:Carbon Isotopes; D004187:Disaccharides / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure
chemical_list: D002247:Carbon Isotopes; D004187:Disaccharides