Author(s):
Pessoa, João Costa 
; 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
Date: 2006
Persistent ID: http://hdl.handle.net/10316/8117
Origin: Estudo Geral - Universidade de Coimbra
Description
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) http://dx.doi.org/10.1002/ejic.200600309
