The complexes of the formula Ln(carb)3(H2O)2 (where Ln = Eu, Tb, Gd, La, Yb; carb = various pyrazolecarboxylic acids) were synthesized and thoroughly characterized. It was shown that the quantum yields of terbium complexes depend mainly on the type of substituents of the ligand, while the quantum yields of europium complexes are influenced by the ligand isomerism due to the presence or absence of the ligand-to-metal charge transfer (LMCT) state. These compounds were successfully tested as bioimaging probes as well as OLED emitting layers due to their high photo- and electroluminescent performance.
Read full abstract