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Vanadium (IV and V) Complexes of Reduced Schiff Bases Derived from the Reaction of Aromatic o ‐Hydroxyaldehydes and Diamines Containing Carboxyl Groups
Author(s) -
Costa Pessoa João,
Marcão Susana,
Correia Isabel,
Gonçalves Gisela,
Dörnyei Agnes,
Kiss Tamás,
Jakusch Tamás,
Tomaz Isabel,
Castro M. Margarida C. A.,
Geraldes Carlos F. G. C.,
Avecilla Fernando
Publication year - 2006
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200600309
Subject(s) - chemistry , salicylaldehyde , stoichiometry , vanadium , electron paramagnetic resonance , spectroscopy , aqueous solution , infrared spectroscopy , nuclear magnetic resonance spectroscopy , crystallography , stability constants of complexes , schiff base , stereochemistry , medicinal chemistry , inorganic chemistry , organic chemistry , physics , nuclear magnetic resonance , quantum mechanics
The reduced Schiff bases of salicylaldehyde [and o ‐vanillin ( o ‐van)] with D , L ‐ and L ‐diaminopropionic acid (DPA), designated by salDPA, and L ‐2,4‐diaminopentanoic acid [ornithine (Orn)], designated by salOrn, as well as the V IV O 2+ and V V O 2 + complexes of salDPA were prepared. The compounds were characterised in the solid state and in solution. The structure of H 4 salDPA + Cl – was determined by X‐ray diffraction. Complexation of V IV O 2+ and V V O 2 + with salDPA and salOrn (only the V IV O system) in aqueous solution was studied by potentiometry, UV/Visible spectroscopy and circular dichroism, as well as by EPR spectroscopy for the V IV O–salDPA system and by 1 H‐ and 51 V NMR spectroscopy for the V V O 2 –salDPA system. Stoichiometries and complex formation constants were determined by potentiometry at 25 °C and I = 0.2 M KCl. Practically only 1:1 complexes were formed in both systems with composition (VO)LH 2 and(VO)L in the V IV O–salDPA system, and with composition(VO 2 )LH and (VO 2 )L in the V V O 2 –salDPA system. Spectroscopic data provided information about the most probable binding modes of each stoichiometry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)