Structure and equilibria of Ca 2+-complexes of glucose and sorbitol from multinuclear ( 1H, 13C and 43Ca) NMR measurements supplemented with molecular modelling calculations

• Published in: Journal of molecular structure Vol. 993; no. 1; pp. 336 - 340
• Main Authors: Pallagi, A., Dudás, Cs, Csendes, Z., Forgó, P., Pálinkó, I., Sipos, P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 03-05-2011
• Subjects: 2D 1H– 43Ca NMR measurements; Ca 2+- d-glucose and Ca 2+- d-sorbitol complexes; Constants; Equilibrium structures; Formation constants; Glucose; Mathematical models; Molecular modelling; Molecular structure; Nuclear magnetic resonance; Sorbitol; Spectra; Two dimensional; Molecular modelling; Equilibrium structures; 2D 1H– 43Ca NMR measurements; Ca 2+- d-glucose and Ca 2+- d-sorbitol complexes; Formation constants
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2010.11.038

Ca
2+-complexation of
d-glucose and
d-sorbitol have been investigated with the aid of multinuclear (
1H,
13C and
43Ca) NMR spectroscopy and
ab initio quantum chemical calculations. Formation constants of the forming 1:1 complexes have been estimated from one-dimensional
13C NMR spectra obtained at constant ionic strength (1
M NaCl). Binding sites were identified from 2D
1H–
43Ca NMR spectra. 2D NMR measurements and
ab initio calculations indicated that Ca
2+ ions were bound in a tridentate manner
via the glycosidic OH, the ethereal oxygen in the ring and the OH on the terminal carbon for the α- and β-anomers of glucose and for sorbitol simultaneous binding of four hydroxide moieties (C1, C2, C4 and C6) was suggested.