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A new porous metal–organic framework (MOF) {[Cd(Hbptc)]·H2O}n (Cdbptc) was assembled by Cd(II) ions and a rigid (1,1′-biphenyl)-2,4,6-tricarboxylic acid (H3bptc) ligand via a solvothermal method. C...

Three isostructural lanthanide metal–organic frameworks (Ln-MOFs), {[Ln(L)(H2O)2]·H2O}n (M-Ln, Ln = Eu/Tb/Dy), were prepared with a flexible 3,5-(4-carboxybenzyloxy) benzoic acid (H3L) ligand and lanthanide ions by a solvothermal method. M-Ln are two-dimensional (2D) grid layer-stacking frameworks. M-Eu exhibits excellent chemical stabilities against organic solvents and shows strong luminescence. The experimental results indicated that M-Eu could be used as an ideal fluorescent probe to detect nitrobenzene (NB) in different solvents with a lower detection limit. M-Eu can also be used as a pH sensor because of its superior water stability. Furthermore, M-Eu and M-Tb show unique strong luminescence properties with high absolute quantum yields. The quantum yields can even reach up to 11.8% and 60.5%, respectively. Simultaneously, various kinds of heterometallic doped M-EuxTb1−x MOFs were acquired by tuning the ratios of Eu3+/Tb3+ ions, showing the unique color changes from red, orange-red, orange, orange-yellow, light yellow, yellow to green.

A new series of isomorphic lanthanide metal–organic frameworks (Ln-MOFs), {[Ln2(L)3·DMF·H2O]·DMF·H2O}n (denoted as 1-Ln, Ln = Eu, Gd, Tb or EuxTb1−x), were constructed using the 4′-(1H-1,2,4-triazol-1-yl)-[1,1′-biphenyl]-3,5-dicarboxylic acid (H2L) ligand and Ln3+ ions under solvothermal conditions. 1-Ln shows a binodal (3,3,8)-connected three-dimensional (3D) framework based on a π-conjugated and uncoordinated Lewis basic triazolyl ligand. Then, six two-color doped 1-EuxTb1−x and the tri-metallic doped 1-Eu0.01Gd0.6015Tb0.3885 with white light emitting MOFs were fabricated by doping diverse concentrations of Eu3+, Tb3+ and Gd3+ ions. More interestingly, 1-Eu0.01Gd0.6015Tb0.3885 has a higher quantum yield (36.49%). Meanwhile, 1-Ln shows excellent performance in fluorescence sensing (Ksv = 1.5143 × 104 M−1) and anticounterfeiting applications.

Five new 3D MOFs: {[Zn3(HL)2H2O]·4H2O}n (1), {[Ba2L5H2O]·2H2O}n (2), {[Ba4(L)2·5H2O]·2H2O}n (3), {[Cd3(HL)2·Cl2·2H2O]·2H2O}n (4) and {[Cu2(L)2·2H2O]·4H2O}n (5), were constructed based on 1-(3,5-dicarboxylatobenzyl)-3,5-pyrazole dicarboxylic acid. Structural analysis shows that 1–5 have 3D frameworks, among which 1(Zn) exhibits high luminescence sensing for Fe3+ ions, excellent framework stability and reusability. The sensing mechanism of 1(Zn) is briefly discussed. In addition, 5(Cu) displays antiferromagnetic exchange phenomena.

Five new 3D MOFs: {[Zn