Multinuclear complex formation in aqueous solutions of Ca(ii) and heptagluconate ions

Attila Pallagi, Zita Csendes, Bence Kutus, Eszter Czeglédi, Gábor Peintler, Péter Forgo, István Pálinkó, Pál Sipos

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14 Citations (Scopus)


The equilibria and structure of complexes formed between the Ca 2+ ion and the heptagluconate (Hglu-) ion in both neutral and alkaline solutions have been studied. In alkaline solutions an uncharged, multinuclear complex is formed with the composition of Ca3Hglu 2(OH)4 (or [Ca3Hglu2H -4]0) with an unexpectedly high stability constant (lg β32-4 = 14.09). The formation of the trinuclear complex was deduced from potentiometry and confirmed by freezing-point depression measurements and conductometry as well. The binding sites of Hglu- were determined from NMR measurements. Besides the carboxylate group, the O atoms on the second and third carbon atoms proved to be the most probable sites for Ca2+ binding.

Original languageEnglish
Pages (from-to)8460-8467
Number of pages8
JournalDalton Transactions
Issue number23
Publication statusPublished - Jun 21 2013

ASJC Scopus subject areas

  • Inorganic Chemistry

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