Complexes of Cerium(III), Thorium(IV) and Dioxouranium(II) with 8-(Arylazo)-7-hydroxy-4-methylcoumarin Dyes

Chemistry Department, Faculty of Science, Cairo University, Giza, Egypt Faculty of Education, Fayoum Manuscript received 26 December 1997, accepted 19 March 1992 Proton-ligand ionisation and metal-ligand stability constants of 8-(arylazo)-7-hydroxy-4-methylcoumarin complexes with CellI, ThIV and \(UO_2II\) ions have been determined pH-metrically in 60% (v/v) ethanol-water mixture at 25° and µ= 0.1. The order of stability constants was found to be ThIV > COIII > \(UO_2II\) 1 : 1 and 1 : 2 (M : L) complexes are formed as evidenced by conductimetric studies. The complexes have been isolated in solid state and characterised on the basis of elemental analyses, thermal, ir and nmr spectral data.