Influence of acetate ions on aluminium, gallium and indium complexing with lumogallion

The comparative investigation of Al, Ga and In complexing with lumogallion (LG) in the absence and in the presence of acetate ions is performed. The influence of acetate ion concentration of optical density of solutions of formed complexes as well as the pH value effect on their light absorption is studied. It has been found that in the absence of acetate ions stability of the metal complexes with LG is decreased in the Ga>In-Al series, whereas the introduction of acetate ions leads to inversion (Ga>Al>In) in the above series. The latter is explained by In binding into colorless acetate complex at pH<5. In the region of higher pH value the LG competitive ness increases due to concentration increase of coordinating dye anions and in these conditions the In coloured complex with lumogallion is formed also in the presence of acetate ions. The composition of formed complexes is established depending on pH value and acetate ion concentration. Electron absorption spectra of coloured complexes are presented