MIXED-LIGAND COMPLEXES OF 3 VALENT LANTHANIDE IONS WITH ACETYLACETONEAND SOME ORGANIC UNSATURATED-ACIDS

The complexation in ternary systems Ln-L-A (Ln-lanthanide ions Ln(III) ; L-acrylic, methacrylic, maleic acids; A-acetylacetone) have been inv estigated by pH-potentiometric titration technique and by NMR spectra lineshape analysis on the base of quantum-mechanical formalism of spin density matrix. Stability constants, NMR spectra, paramagnetic shifts , relaxation times and lifetimes of mixed-ligand complexes were determ ined. General conformities of the complexation according to the lantha nide row were revealed. The dependences of complex compounds stability on the lanthanide ionic radius are explained by joint influence of el ectrostatic and steric effects. (C) 1998 Elsevier Science Ltd. All rig hts reserved.