Synthesis, crystal structure and photophysical properties of europium(III) and terbium(III) complexes with pyridine-2,6-dicarboxamide

The reactions of pyridine-2,6-dicarboxamide with europium(III) and terbium(III) triflates led to the formation of mononuclear complexes of formula [Ln(pcam)3](CF3SO3)3 (Ln = Eu 1, Tb 2; pcam stands for pyridine-2,6-dicarboxamide). From single-crystal X-ray diffraction analysis, the complexes were found to be isomorphous and isostructural. The [Ln(pcam)3]3+ cations and triflate counterions are connected by intermolecular hydrogen bonds, resulting in a 3D network structure. Both the europium(III) and terbium(III) complexes exhibit efficient ligand sensitized luminescence in the visible region with lifetimes of 1.9 ms and 2.2 ms, respectively, in the solid state.