MULTIPLE-FIELD C-13 NMR RELAXATION INVESTIGATION ON MELEZITOSE

Citation
L. Maler et al., MULTIPLE-FIELD C-13 NMR RELAXATION INVESTIGATION ON MELEZITOSE, Magnetic resonance in chemistry, 33(7), 1995, pp. 541-548
Citations number
31
Categorie Soggetti
Spectroscopy,Chemistry
ISSN journal
07491581
Volume
33
Issue
7
Year of publication
1995
Pages
541 - 548
Database
ISI
SICI code
0749-1581(1995)33:7<541:MCNRIO>2.0.ZU;2-9
Abstract
Multiple-field carbon-13 relaxation data are reported for melezitose, a trisaccharide consisting of two alpha-linked glucose residues attach ed at positions 2 and 3 to a beta-linked fructofuranose residue, Value s for T-1 and NOE were measured at 4.7, 9.4, 11.8 and 14.1 T and trans verse relaxation rates at 4.7 and 9.4 T. The measurements were carried out by means of standard techniques and by polarization transfer (INE PT) enhanced methods. The relaxation data were interpreted with the Li pari-Szabo 'model-free' approach. It was found that the relaxation dat a of the ring carbons can be described by the use of the truncated for m of the Lipari-Szabo equation, The global correlation time and order parameter for melizitose were calculated at two temperatures. For the exocyclic CH2 carbons, fits to obtain a local correlation time are rep orted For three out of the four exocyclic carbons, a fast correlation time is obtained and their order parameter is lower than that for the ring carbons., The fructose C-l exocyclic carbon does not seem to disp lay the same local motions as the other CH2 groups, and a higher order parameter is obtained indicating hindered local motion of that CH2 gr oup.