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Multiple‐field carbon‐13 NMR relaxation investigation on melezitose
Author(s) -
Mäler Lena,
Lang Jan,
Widmalm Göran,
Kowalewski Jozef
Publication year - 1995
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260330708
Subject(s) - chemistry , relaxation (psychology) , carbon fibers , analytical chemistry (journal) , ring (chemistry) , stereochemistry , crystallography , computational chemistry , nuclear magnetic resonance , organic chemistry , physics , psychology , social psychology , materials science , composite number , composite material
Multiple‐field carbon‐13 relaxation data are reported for melezitose, a trisaccharide consisting of two α‐linked glucose residues attached at positions 2 and 3 to a β‐linked fructofuranose residue. Values for T 1 and NOE were measured at 4.7, 9.4, 11.8 and 14.1 T and transverse relaxation rates at 4.7 and 9.4 T. The measurements were carried out by means of standard techniques and by polarization transfer (INEPT) enhanced methods. The relaxation data were interpreted with the Lipari‐Szabo ‘model‐free’ approach. It was found that the relaxation data of the ring carbons can be described by the use of the truncated form of the Lipari‐Szabo equation. The global correlation time and order parameter for melizitose were calculated at two temperatures. For the exocyclic CH 2 carbons, fits to obtain a local correlation time are reported. 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‐1 exocyclic carbon does not seem to display the same local motions as the other CH 2 groups, and a higher order parameter is obtained indicating hindered local motion of that CH 2 group.