A series of rare earth complexes with novel non-interpenetrating 3D networks: synthesis, structures, magnetic and optical properties?

摘要

A series of metal-organic framework {Ln(BCPBA)(H_2O)}_n {Ln = Nd (1), Sm (2), Eu (3), Tb (4), Dy (5)}; {[Ln- (BCPBA)(H_2O)](H_2O)}_n {Ln = Pr (6), Gd (7)} have been synthesized through the hydrothermal synthesis method. These compounds possess non-interpenetrating 3D networks with 10.1438 ? × 17.9149 ? rhombic channels along the [001] direction. The results of temperature-dependent magnetic susceptibility measurements indicate that compounds 4 and 7 exhibit Ln~(_(III))?Ln~(_(III)) antiferromagnetic interactions, while compound 5 exhibits Ln~(_(III))?Ln~(_(III)) ferromagnetic interactions. Frequency dependent out-of-phase signals were observed in alternating current (ac) magnetic susceptibility measurements which indicate that they have slow magnetic relaxation characteristics. The luminescent properties of 1, 2, 3, 4, and 5 are also discussed. Due to the good match between the lowest triplet state of the ligand and the resonant energy level of the lanthanide ion, compound 4 has longer fluorescence lifetime (τ1 = 400.0000 ms, τ2 = 1143.469 ms) and higher quantum yield (Ф = 42%) compared with other compounds.