Syntheses, Structures, and Luminescent and Magnetic Properties of Novel Three-Dimensional Lanthanide Complexes with 1,3,5-Benzenetriacetate

Five novel lanthanide complexes with the formulas [Nd(bta)(H2O)2·4.35H2O]n (1), [Sm(bta)(H2O)2·4.5H2O]n (2), [Eu(bta)(H2O)·1.48H2O]n (3), [Tb(bta)(H2O)·1.31H2O]n (4), and [Yb(bta)(H2O)·H2O]n (5) (H3bta = 1,3,5-benzenetriacetic
acid) have been prepared by using the corresponding lanthanide salt and H3bta. The results of an X-ray
crystallographic analysis revealed that all the complexes have three-dimensional channel-like structures, in which
the bta3- ligands adopt different coordination modes:  monodentate and μ2-η2:η1-bridging coordination modes in
1, 2, and 5 and μ2-η1:η1-bridging and μ2-η2:η1-bridging coordination modes in 3 and 4, respectively. Complexes
1 and 2, as well as 3 and 4, are isostructural, respectively, in which all the LnIII (Ln = Nd, Sm, Eu, and Tb) atoms
are nine-coordinated, while the YbIII atoms in complex 5 are eight-coordinated. Both complexes 3 and 4 showed
strong luminescence upon excitation, and their luminescence decay curves fit well with single exponential decays
of which the lifetime is 0.45 ms for 3 and 1.0 ms for 4. The magnetic properties of the complexes were investigated
in the temperature range of 1.8−300 K.