Synthesis and luminescent properties of color-tunable lanthanide complexes with 5-(pyridin-4-yl)isophthalic acid

In this work, a T-shape organic molecule 5-(pyridin-4-yl)isophthalic acid was synthesized via a Suzuki coupling reaction and used as the ligand for a serial of mixed-lanthanide complexes. The chemical compositions of the lanthanide complexes were determined as (EuxTb1−x)2L3(H2O)4 by elemental analysis (EA) and thermo gravimetric analysis (TGA). The luminescent properties of the as-synthesized complexes were investigated and the intramolecular energy transfer mechanisms involved, were discussed. Efficient energy transfer from Tb3+ to Eu3+ was observed and controlled by changing the molar ratio of Tb3+ to Eu3+ ions, allowing the color tuning on the luminescent emission of the mixed-lanthanide complexes.