Abstract
Homoleptic, 3D coordination polymers of the formula (33) (∞) [Ln(3-PyPz)(3) ] and (3) (∞) [Ln(4-PyPz)(3) ], (3-PyPz)(-) =3-(3-pyridyl)pyrazolate anion, (4-PyPz)(-) =3-(4-pyridyl)pyrazolate anion, both C(8) H(6) N(3) (-) , Ln=Sm, Eu, Gd, Tb, Dy, were obtained as highly luminescent frameworks by reaction of the lanthanide metals (Ln) with the aromatic heterocyclic amine ligands 3-PyPzH and 4-PyPzH. The compounds form two isotypic series of 3D coordination polymers and exhibit fair thermal stability up to 360 °C. The luminescence properties of all ten compounds were determined in the solid state, with an antenna effect through ligand-metal energy transfer leading to high efficiency of the luminescence displayed by good quantum yields of up to 74 %. The emission is mainly based on ion-specific lanthanide-dependent intra 4 f-4 f transitions for Tb(3+) : green, Dy(3+) : yellow, Sm(3+) : orange-red, Eu(3+) : red. For the Gd(3+) -containing compounds, the yellow emission of ligand triplet-based phosphorescence is observed at room temperature and 77 K. Co doping of the Gd-containing frameworks with Eu(3+) and Tb(3+) allow further shifting of the chromaticity towards white light emission.