STUDIES ON LANTHANIDE COMPLEXES WITH PYRONE LIGANDS .5. TERBIUM(III) AND EUROPIUM(III) COMPLEXES WITH A NEW LIGAND DERIVED FROM THE CONDENSATION OF 4-OXO-4H-BENZOPYRAN-3-CARBOXYALDEHYDE AND 2-AMINO-4-CHLOROPHENOL

A novel ligand, 3-[(2-hydroxy-5-chlorophenylamino)methoxy]methylchromone, Hbpcap, was obtained by reacting 4-oxo-4H-benzopyran-3-carboxyaldehyde, bpa, and 2-amino-4-chlorophenol, cap, in methanol. Elemental analysis and vibrational and NMR spectra revealed that Hbpcap is a cathecolamine derivative of bpa. Complexes, of general formula Ln(bpcap)2X·nH2O (Ln3+ = Eu3+ and n = 2; Ln3+ = Tb3+ and n = 1; X- = NO3+, Cl-, ClO4-), were isolated and characterized. Unlike the bpa complexes with Eu3+ and Tb3+, they did not exhibit ionic emission due to the excitation of the ligand. In order to explain this behaviour, the ligand excited states have been examined. © 1990.