Abstract: | In the context, some lanthanide (Eu3+, Tb3+ and Sm3+) complexes with conjugated carboxylic acids (pyridine-carboxylic acids derivatives) have been synthesized and characterized. The low temperature fluorescent spectra for these complexes have been measured at nitrogen atmosphere (77 K), indicating that the central Ln3+ ions locate in an equivalent coordination environment with low symmetry for most of these lanthanide complexes belonging to dimeric or polymeric structure. Therefore, the electronic dipole transition (supersensitive transition) (5D0 → 7F2 for Eu3+, 5D4 → 7F6 for Tb3+, 4G5/2 → 6H9/2 for Sm3+) and magnetic dipole transition (5D0 → 7F1 for Eu3+, 5D4 → 7F5 for Tb3+, 4G5/2 → 6H5/2 for Sm3+) show the regular change in the corresponding split number of fluorescent spectra, which can be realized to predict the fine structure of lanthanide complexes. |