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Carbon-13 NMR relaxation studies of gluconate and manganese—gluconate interactions

✍ Scribed by David B. Coffin; W. Robert Carper

Publisher
John Wiley and Sons
Year
1988
Tongue
English
Weight
345 KB
Volume
26
Category
Article
ISSN
0749-1581

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✦ Synopsis

The effect of temperature on the spin-lattice ( R , ) and spin-spin (R,) I3C relaxation rates of gluconate and manganese (II)-gluconate interactions was determined in D,O. An R, vs T-' minimum was observed for gluconate similar to that observed in solid-liquid phase transitions. Nuclear Overhauser enhancement factors indicated predominately dipolar relaxation mechanisms for all atoms except the carbonyl carbon. Activation energies and chemical shifts indicated a molecular reorientation involving the carbonyl carbon which resulted in changes in solvation effects. Addition of manganese(I1) to gluconate in D,O resulted in an observed minimum in the R , vs Tplots for all carbon atoms except the carbonyl species. The activation energies further supported the concept of changes in solvent-manganese-gluconate interactions produced by variations in intramolecular structure.

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