Structural Diversity of Three Pyrazoyl–Carboxyl Bifunctional Ligand-Based Metal–Organic Frameworks: Luminescence and Magnetic Properties

Three metal–organic frameworks (MOFs), [Cd(Hpzbpdc)(H2O)]⋅H2O (1), [Mn2(Hpzbpdc)2(dmf)2] (2), and [H2N(CH3)2]0.5[Eu(Hpzbpdc)1.5(HCOO)0.5(dmf)0.5]⋅DMF⋅0.5 H2O (3) (H3pzbpdc=4′-(2 H-pyrazol-3-yl)biphenyl-3,5-dicarboxylic acid), have been solvothermally synthesized from one pyrazoyl–carboxyl bifunctional ligand and characterized by single-crystal structures. The H3pzbpdc ligand in 1–3 displays various coordination modes through the pyrazoyl and carboxyl groups. Both 1 and 3 contain dinuclear cluster building units and reveal a four-connected gismondine (gis) zeolite 3D framework and a 2D grid layer structure, respectively. Compound 1 shows blue luminescence, compound 3 reveals red luminescence that arises from efficient energy transfer from the organic ligand to the europium(III) ion, and compound 2 reveals an uncommon (3,8)-connected tfz-d; UO3 net with a rare Mn4(COO)6 cluster and shows antiferromagnetic interactions between the manganese(II) ions.