Synthesis, characterization and luminescence properties of N,N′-bis(2-pyridinecarboxamide-1-N-oxide)-1,2-ethane and corresponding lanthanide(III) complexes

Several lanthanide (Ln) complexes (Ln=Eu(III), Gd(III), Tb(III)) with a new ligand N,N′-bis(2-pyridinecarboxamide-1-N-oxide)-1,2-ethane (LH2), containing two pyridine N-oxide chromophores and a flexibly connected N,N′-dicarboxamide-1,2-ethane, have been prepared and characterized by elemental analysis, conductivity measurements, IR spectra and thermal studies. The luminescence properties of the series of lanthanide complexes in solid state were investigated. Also, we compared the relative fluorescent intensities of these complexes with corresponding complexes with nonoxide derivative N,N′-bis(2-pyridinecarboxamide)-1,2-ethane (L′H2). The results have shown that pyridine-N-oxide group is an excellent sensitizer to lanthanide luminescence over pyridine group.