Two novel lanthanide(III) organic frameworks based on a biphenyltetracarboxylate ligand: synthesis, structure and magnetic and luminescence properties

Abstract

Two new two-dimensional lanthanide coordination polymers, namely poly[[tetra-μ2-acetato-tetraaquabis(μ4-biphenyl-3,3′,5,5′-tetracarboxylato)tetrakis(dimethylacetamide)tetraterbium(III)] pentahydrate], {[Tb4(C16H6O8)2(C2H3O2)4(C4H9NO)4(H2O)4]·5H2O}n, (1), and poly[[tetra-μ2-acetato-tetraaquabis(μ5-biphenyl-3,3′,5,5′-tetracarboxylato)tetrakis(dimethylacetamide)tetraeuropium(III)] tetrahydrate], {[Eu4(C16H6O8)2(C2H3O2)4(C4H9NO)4(H2O)4]·4H2O}n, (2), have been synthesized from biphenyl-3,3′,5,5′-tetracarboxylic acid (H4bpt) and Ln(NO3)3·6H2O (Ln = Tb and Eu) under solvothermal conditions. Single-crystal X-ray structure analysis shows that the two compounds are isostructural and crystallize in the monoclinicP21/nspace group. The crystal structures are constructed from bpt4−ligands (as linkers) and {Ln2(μ2-CH3COO)2} building units (as nodes), which topological analysis shows to be a (4,6)-connected network withsqltopology. Compounds (1) and (2) have been characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and fluorescence analysis in the solid state. In addition, a magnetic investigation shows the presence of antiferromagnetic interactions in compound (1).