Two Series of Microporous Lanthanide-Organic Frameworks with Different Secondary Building Units and Exposed Lewis Base Active Sites: Sensing, Dye Adsorption, and Magnetic Properties.

Two series of new lanthanide complexes, {[Ln(L)1.5(H2O)]·DMA·4H2O} n (1-Ln, Ln = Tb, Gd, and Dy) and {[La2(L)3]·4H2O} n (2-La), were prepared successfully by Ln3+ ions and a N-heterocyclic dicarboxylic (2-pyrimidin-5-yl)terephthalic acid (H2L) ligand. The four complexes are three-dimensional (3D) microporous frameworks with different secondary building units (SBUs) and exposed Lewis base active sites. Topology analyses reveal that 1-Ln are the binodal (3,8)-connected tfz-d (43)2(46·618·84) nets and 2-La is a binodal (2,12)-connected (4)6(46·848·1212) net. The photoluminescence of 1-Tb, the dye adsorption of 1-Tb and 2-La, and the magnetism of 1-Dy have been well studied. The luminescent explorations indicate that 1-Tb is a highly efficient probe for sensing Fe3+ and Cr2O72-, respectively. Complexes 1-Tb and 2-La display the unique selective adsorption to Congo red (CR) dyes. Magnetic measurements further indicate that 1-Dy has a slow magnetic relaxation performance.