Tris(tropolonato)phenanthroline lanthanide(III) complexes as photochemical devices

The tris-tropolonato erbium(III) complexes [Er(hino)3(phen)] and [{Er(hino)3}2(pdon)] (H-hino = 2-hydroxy-6- isopropylcyclohepta-2,4,6-trien-1-one; phen = 1,10-phenanthroline; pdon = 1,10-phenanthroline-5,6-dione) have been prepared by reaction of [Er(hino) 3]n with the appropriate chelating ligand in alcoholic solution. The complexes were characterized by elemental analyses, TG, ESI MS, 1H NMR, and IR spectroscopy, also by comparison with the properties of the analogous EuIII and YbIII complexes. The ESI-MS spectroscopy of the complex with the ditopic ligand pdon parallels the other physico-chemical data (IR, NMR), confirming the occurrence of a dinuclear entity. All the investigated ErIII complexes show efficient NIR emissions at about 1550 nm upon excitation at 355 nm in the UV ligand absorption band, emerging as possible candidate as active material for the realization of plastic amplifiers for telecommunications