Solution-Stability Relationships of Metal 8-Hydroxyquinolinates

Abstract

<p> The solution stability of chelates formed between several metal-ions and 5-substituted-8-hydroxyquinolines has been determined. The dependence of solution stability on (a) the solvent composition, and (b) the basicity of the ligand donor sites has been examined.</p> <p> It was found that the effect of solvent composition on metal chelate stability is essentially independent of the metal-ion. A mathematical description of the relationship between metal-chelate stability and ligand basicity has been derived and gives excellent agreement with the experimental data. The relative contributions of the N-M and the O-M bond to chelate stability are evaluated and shown to vary slightly with the metal-ion. Also, the character of the bonding in the metal chelates is implied.</p>