Fluorescence Spectra of Homogeneous and Mixed Europium Complexes

High-resolution emission spectra of several europium complexes with β-diketones, dipyridyl, and phenanthroline have been examined at 77°K in microcrystals. The Stark splitting of the 7F levels in the ground multiplet and the relative intensities of the individual 5D0→7F transitions can be used for theoretical correlation with the ligand field parameters, transition probabilities, molecular structure, and Eu-ligand bonding. The fluorescence spectra of the bis-aqua, tris, tris-aqua, tetrakis, and mixed chelates with the bidentate ligands are discussed in relation to molecular configuration.