Configuration-dependent complex formation between Ca(II) and sugar carboxylate ligands in alkaline medium: Comparison of L-gulonate with D-gluconate and D-heptaguconate

Bence Kutus, Csilla Dudás, Gábor Peintler, István Pálinkó, Pál Sipos

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The calcium sugar carboxylate interactions in hyperalkaline solutions are of relevance in radioactive waste repositories and in certain industrial processes. The complex formation between L-gulonate and Ca2+ ions was studied in strongly alkaline medium at 25 °C and 1 M ionic strength and was compared with previous results reported for D-gluconate and D-heptagluconate. The deprotonation of the ligand was confirmed by potentiometric and 13C NMR spectroscopic measurements. Pronounced pH effects were seen in the presence of Ca2+ indicating strong complex formation. By the evaluation of the experimental data, two highly stable trinuclear species, Ca3Gul2H–3 + and the Ca3Gul2H–4 0, are formed in alkaline aqueous solutions. Polarimetric as well as 1H NMR spectroscopic measurements attested that the increased complex stability was due to the formation of strong metal ion - alcoholate interactions. Moreover, the 1H NMR spectra of the three anions refer to the role of configuration in metal ion-binding. That is, the participation of the C3-OH or C4-OH group is governed by the relative position (i.e., threo or erythro) of the C2-OH and C3-OH groups.

Original languageEnglish
Pages (from-to)34-40
Number of pages7
JournalCarbohydrate Research
Volume460
DOIs
Publication statusPublished - May 2 2018

Keywords

  • Calcium
  • Complexation
  • Configuration-dependence
  • D-gluconate
  • D-heptagluconate
  • L-gulonate

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry

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