A novel dinuclear species in the aqueous distribution of aluminum in the presence of citrate

Maria Dakanali, Catherine P. Raptopoulou, Aristidis Terzis, Andrea Lakatos, Istvan Banyai, Tamas Kiss, Athanasios Salifoglou

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13 Scopus citations


The chemistry of aluminum was explored in the presence of the physiological ligand citric acid and in low-pH aqueous media. As a result, the first dinuclear aluminum-citrate complex (NH4)4[Al2-(C6 H4O7)(C6H5 O7)2]·4H2O was isolated at low pH (∼3.5), and was characterized by FT-IR spectroscopy and X-ray crystallography. The structural analysis reveals the presence of a dinuclear assembly of two aluminum ions octahedrally coordinated to three citrate ligands of differing protonation state. The NMR solution behavior of this complex emphasizes its time-dependent transformation into a number of variable nature species, ultimately leading to the thermodynamically stable trinuclear species. It also establishes the participation of the dinuclear complex as a viable component of the aqueous AI(III)-citrate speciation. The chemical and structural features of this novel low molecular mass species provide considerable insight into citrate's ability, as a natural ligand, to influence the chemistry of aluminum in a pH-dependent fashion, and potentially affect aluminum's (bio)distribution, absorption, accumulation, and biotoxicity at sensitive biological sites.

Original languageEnglish (US)
Pages (from-to)252-254
Number of pages3
JournalInorganic Chemistry
Issue number2
StatePublished - Jan 27 2003

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry


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