COMPLEXES OF LANTHANIDE(III) IONS WITH MACROCYCLIC LIGANDS CONTAININGPYRIDINE HEAD UNITS

Lanthanide(III) salts were found to act as templates for the cyclic co ndensation of organic dicarbonyl compounds with primary diamines to yi eld complexes of macrocyclic Schiff-base ligands in moderate to good y ield. Three types of macrocyclic lanthanide(III) complexes were obtain ed: (i) mononuclear complexes of an 18-membered sexidentate N3O3 macro cycle derived from the reaction of 2,6-diacetylpyridine with 1,5-bis(2 -aminophenoxy)-3-oxapentane; (ii) mononuclear complexes of 15-membered pentadentate N3O2 macrocycles derived from the reactions of 2,6-diace tyl- or 2,6-diformyl-pyridine with 1,2-bis(2-aminophenoxy)ethane. The complexes were characterised by elemental analyses, molar conductivity , mass, IR and H-1 NMR spectroscopy and thermogravimetric and magnetic measurements.