Abstract
The new complexes [M(BHBDAE)(H2O)(2)] (Co(II), Ni(II), Cu(II) and Zn(II); BHBDAE: N,N'-bis(2-hydroxybenzylidene)-1,1-diaminoethane) have been synthesized and characterized by IR, EPR, H-1 NMR, magnetic moment as well as electronic spectroscopy data. The stepwise formation of the complexes has been established in the pH region studied. The results show the formation of 1:1 complexes with amino acids. Protonation constants of Schiff base (H(2)BHBDAE) and stability constants of their binary Co(II), Ni(II), Cu(II) and Zn(II) complexes have been determined potentiometrically in 50% DMSO-water media at 37 degrees C and ionic strength 0.10 mol dm(-3) sodium nitrate. The concentration distribution of the complexes in solution was evaluated.