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Al III Ion Complexes of Saccharic Acid and Mucic Acid: A Solution and Solid‐State Study
Author(s) -
Lakatos Andrea,
Bertani Roberta,
Kiss Tamas,
Venzo Alfonso,
Casarin Maurizio,
Benetollo Franco,
Ganis Paolo,
Favretto Donata
Publication year - 2004
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200305328
Subject(s) - chemistry , potentiometric titration , crystallography , density functional theory , ion , ligand (biochemistry) , solid state , stereochemistry , computational chemistry , inorganic chemistry , organic chemistry , biochemistry , receptor
The Al III ‐binding abilities of two aldaric acids, D ‐saccharic acid and mucic acid (the neutral form is denoted as H 2 L), were studied in solution by means of pH potentiometric, 1 H and 13 C NMR, and ESI‐MS techniques. The most probable conformations and isomeric binding modes of the complexes formed in solution were determined by density functional theory (DFT) calculations. A solid D ‐saccharic acid complex K 2 [{Al(LH −2 )(H 2 O)} 2 ]⋅H 2 O was isolated and crystallographically characterised. The two alcoholic hydroxy groups α to the terminal COO − groups were found to take part in the coordination, but in different ways. One of them coordinates in a bridging mode. Detailed ESI‐MS and NMR studies proved that the complex retains its structure in solution. However, depending on the ligand and the pH, such complexes may exist in two isomeric forms. DFT calculations on the ion [{Al(LH −2 )(H 2 O)} 2 ] 2− revealed that several orbitals participate in stabilizing the dimeric arrangement.