Complexion de metaux de transition par des hydroxyquinolines en milieux homogenes et microheterogenes : influence de l'hydrophobie du ligand sur la cinetique reactionnelle dans des phases microemulsions

SIGLECNRS T 62138 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Stopped-flow study of the kinetics and mechanism of nickel (II). Complexation with 8-Hydroxyquinoline in basic aqueous solutions

The complexation of nickel (II) with 8-hydroxyquinoline is studied in basic aqueous solutions buffered with triethanolamine. The pH influence is interpreted quantitatively in terms of a mechanism involving the neutral (LH) and anionic (L-) forms of the ligand in addition to the metallic species Ni2+ and Ni(OH)+ . Due to the large similitude existing between the ionization constant of the ligand on the one hand the hydrolysis constant of the metal on the other hand, the influence of the pH on the kinetics of complexation can originate as well from reaction LH + Ni(OH)* as from reaction L- + Ni2+. It is show that the ambiguity cannot be removed by studying the ionic strength dependence of the reaction rate