Vanadium (IV and V) Complexes of Reduced Schiff Bases Derived from the Reaction of Aromatic o -Hydroxyaldehydes and Diamines Containing Carboxyl Groups

• Autor(a) principal: Pessoa, João Costa
• Data de Publicação: 2006
• Outros Autores: Marcão, Susana, Correia, Isabel, Gonçalves, Gisela, Dörnyei, Agnes, Kiss, Tamás, Jakusch, Tamás, Tomaz, Isabel, Castro, M.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/8117; https://doi.org/10.1002/ejic.200600309

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 VIVO2+ and VVO2+ complexes of salDPA were prepared. The compounds were characterised in the solid state and in solution. The structure of H4salDPA+Cl- was determined by X-ray diffraction. Complexation of VIVO2+ and VVO2+ with salDPA and salOrn (only the VIVO system) in aqueous solution was studied by potentiometry, UV/Visible spectroscopy and circular dichroism, as well as by EPR spectroscopy for the VIVO-salDPA system and by 1H- and 51V NMR spectroscopy for the VVO2-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)LH2 and(VO)L in the VIVO-salDPA system, and with composition(VO2)LH and (VO2)L in the VVO2-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)