The (VO)-O-IV complex formation by a number of sugar ligands and their phosphate derivatives has been studied by the combined application of pH-potentiometric and spectroscopic (EPR and electronic absorption) techniques. The study allows a comparison of the relative effectiveness of phosphate and sugar residues in (VO)-O-IV binding, Quinic. acid (Quin) behaves similarly as a sugar molecule provided with chelating sets consisting of carboxyl and either deprotonated or undissociated hydroxy groups, or of couples of adjacent alkoxo, groups. Glucuronic and galacturonic. acids (Glu-Ac and Gal-Ac, respectively) are carboxylic, sugars. The position of the OH(4) group, cis or trans with respect to the carboxylic function, is critical for the complexing behaviour. In both cases the closure of a six-membered chelated ring is possible and bis chelated species are formed but only with galacturonic acid. Both these ligands co-ordinate via the alkoxo groups in basic solution. Uridine 5 ' -diphosphoglucose (UDP-Glu) and uridine 5 ' -diphosphoglucuronic acid (LTDP-Glu-Ac) act as diphosphate ligands at low pH. The glucuronic residue permits the carboxylate site to compete effectively with the phosphate moiety in the acidic pH range and to form a transient species with (CO2-, O-) donor set. However, hydroxo species predominate in the neutral and basic pH range, whereas the sugar co-ordination is observed only in very basic solution. The chelation ability of carboxylic sugars is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.

Oxovanadium(IV) binding to ligands containing donor sites of biological relevance / Garribba, Eugenio; Lodyga Chruscinska, E; Sanna, D; Micera, Giovanni. - In: INORGANICA CHIMICA ACTA. - ISSN 0020-1693. - 322:1-2(2001), pp. 87-98. [10.1016/S0020-1693(01)00554-0]

Oxovanadium(IV) binding to ligands containing donor sites of biological relevance

GARRIBBA, Eugenio;MICERA, Giovanni
2001-01-01

Abstract

The (VO)-O-IV complex formation by a number of sugar ligands and their phosphate derivatives has been studied by the combined application of pH-potentiometric and spectroscopic (EPR and electronic absorption) techniques. The study allows a comparison of the relative effectiveness of phosphate and sugar residues in (VO)-O-IV binding, Quinic. acid (Quin) behaves similarly as a sugar molecule provided with chelating sets consisting of carboxyl and either deprotonated or undissociated hydroxy groups, or of couples of adjacent alkoxo, groups. Glucuronic and galacturonic. acids (Glu-Ac and Gal-Ac, respectively) are carboxylic, sugars. The position of the OH(4) group, cis or trans with respect to the carboxylic function, is critical for the complexing behaviour. In both cases the closure of a six-membered chelated ring is possible and bis chelated species are formed but only with galacturonic acid. Both these ligands co-ordinate via the alkoxo groups in basic solution. Uridine 5 ' -diphosphoglucose (UDP-Glu) and uridine 5 ' -diphosphoglucuronic acid (LTDP-Glu-Ac) act as diphosphate ligands at low pH. The glucuronic residue permits the carboxylate site to compete effectively with the phosphate moiety in the acidic pH range and to form a transient species with (CO2-, O-) donor set. However, hydroxo species predominate in the neutral and basic pH range, whereas the sugar co-ordination is observed only in very basic solution. The chelation ability of carboxylic sugars is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.
2001
Oxovanadium(IV) binding to ligands containing donor sites of biological relevance / Garribba, Eugenio; Lodyga Chruscinska, E; Sanna, D; Micera, Giovanni. - In: INORGANICA CHIMICA ACTA. - ISSN 0020-1693. - 322:1-2(2001), pp. 87-98. [10.1016/S0020-1693(01)00554-0]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11388/62589
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