Stability constants of dioxouranium(VI) complexes with some 5-(arylazo)-8-hydroxyquinolines

The successive stability constants of UO22+ complexes with some 5-(arylazo)-8-hydroxyquinolines have been determined potentiometrically using Bjerrum's method at 27±0.1degC and ionic strength 0.1 in 40 per cent (v/v) ethanol-water medium. The stability constants and the stability factor (St) of the metal chelates are correlated to Hammett substituent constant (σ) and molecular structure. The structures of the complexes have been assigned on the basis of elemental analyses and IR spectroscopy; it is found that chelation occurs through the O and N atoms of the quinoline moiety. (author)