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Four new isostructural lanthanide–organic frameworks, [Ln(L)(H2O)2]·H2O·CH3CN (1-Ln) (Ln = Eu, Tb, Dy, and Gd), have been successfully synthesized via solvothermal reactions with a semi-rigid V-shaped multicarboxylate ligand 2-(2′,4′-dicarboxylphenoxy) benzoic acid (H3L) and Ln(NO3)3·6H2O. 1-Ln shows 2D layer-by-layer frameworks with interlayer channels decorated by carboxylate groups. 1-Eu exhibits excellent luminescence properties, and therefore, is chosen as a probe for sensing different metal ions and anions. Consequently, 1-Eu displays high selectivity and sensitivity for Fe3+ and Cr6+ ions, simultaneously, through the luminescence quenching effect, and thus, should be an excellent candidate for probing these pollutant metal ions. In addition, antiferromagnetic exchange interactions also exist between the Dy3+ ions in 1-Dy. [ABSTRACT FROM AUTHOR]

Three new Cd(ii)-MOFs, [Cd(L1)0.5(bpp)] (1), [Cd(L1)0.5(bipy)] (2), and [Cd(L2)0.5(bipy)] (3) [H4Ln = (1,1′:4′,1′′-terphenyl)-2′,x,x′′,5′-tetracarboxylic acid (n = 1, x = 3, and n = 2, x = 4), bpp = 1,3-di(4-pyridyl)propane, and bipy = 2,2′-bipyridine], have been synthesized using Cd(ii) ions and isomeric H4Ln ligands in the presence of auxiliary ligands via solvothermal reaction, and have been fully characterized by elemental analysis, FT-IR spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Complex 1 is a three-dimensional (3D) pillar-layered network built from L14− and bridging bpp co-ligands with a binodal (4,8)-connected gsp2 topology and a symbol of (44·62)(416·612). 2 was successfully synthesized using bipy instead of the bpp ligand used to assemble 1 giving a 2D 4-connected sql net. 3 is a 3D reticular framework with [Cd2(COO)4] SBUs based on L24− ligands, displaying a (4,4)-connected lvt (42·84) topology. X-ray diffraction analysis revealed that the structures of the MOFs can be mediated by the steric effect of the tetracarboxylate and secondary co-ligands. The solid-state luminescence properties of the MOFs were measured carefully by ultraviolet irradiation at room temperature. In particular, 3 exhibited a high sensitivity for Fe3+ in aqueous solutions of mixed metal ions, which makes it a promising crystalline material to be a luminescent probe for Fe3+. Importantly, 3 can keep its original framework and be reused in sensing experiments. The sensing mechanism has also been studied in detail. [ABSTRACT FROM AUTHOR]

Four new coordination polymers (CPs), [Co3(L)2(bib)3(EtOH)2]·2H2O (1), [Mn3(L)2(bib)2(H2O)4]·4H2O (2), [Ni(HL)(bib)(H2O)3] (3) and [Ni3(bib)4(H2O)10]·2(L)·12(H2O) (4), were synthesized under solvothermal conditions with an unsymmetrical tricarboxylic acid ligand [biphenyl-3,3',5-tricarboxylic acid (H3L)] in the presence of the 1,4-bis(1H-imidazol-4-yl)benzene (bib) ligand. In compound 1, tricarboxylate acid ligands (H3L) link Co centers to generate two-dimensional (2D) layers which are further connected by bib ligands to exhibit a three-dimensional (3D) framework with a (4,4,5)-connected (4²·6³·8)2(4²·67·8)2(64·8·10) topology. The three-dimensional (3D) framework of 2 is defined as a (3,3,4)-connected topology with the point symbol of (6·8²)2(6²·8)2(8·104·12). Compound 3 contains a one-dimensional (1D) left-hand helix chain along the a direction and further extends into a 2D supramolecular network and a 3D supramolecular framework via hydrogen bonds. Compound 4 displays a one-dimensional (1D) molecular ladder, which is further combined with each other through π...π stacking to extend into 2D supramolecular sheets. The supramolecular networks of 3 and 4 resulted from the different solvent ratios [V(H2O)-V(EtOH)] in the reaction. All the CPs are characterized by single-crystal X-ray diffraction analyses, powder X-ray diffraction (PXRD), elemental analyses, IR spectroscopy, and TGA analyses. Moreover, the weak ferromagnetic properties of 2 and 3 and antiferromagnetic properties of 1 and 4 have also been investigated. [ABSTRACT FROM AUTHOR]

By reacting an asymmetry semi-rigid Y-shaped/L-shaped linker H3cpta (H3cpta = 3-(4'-carboxyphenoxy)- phthalic acid) and Co(CH3COO)3'6H2O under different N-donor ligands in different solvents, three new Co-based coordination polymers, [Co3(cpta)2(bpe)3(H2O)4] (1) [Co(μ2-H2O)(μ3-OH)(Hcpta)(bpe)(H2O)' 3(DMF)3(H2O)] (2) and [Co3(cpta)2(bpa)4] (3) have been obtained. They exhibit trinodal topological nets/ layer, based on Co2+ ions and Y-shaped/L-shaped carboxylate linkers. 1 and 3 present 3D frameworks with the point symbol {4·102}2{105·12}{4·85}2 for 1 and {4·82}3{85·9}{4·67·92}3 for 3. While, 2 exhibits a 2D layer with the point symbol {4·6·8}{4·62·83}{62·8}. The magnetic studies indicate that all of the three complexes show antiferromagnetic exchanges transmitted through μ3-carboxylate/μ4-carboxylate bridges, μ2- H2O molecules and μ3-OH ions between Co2+ ions, respectively. And the result of this research shows that the solvent and the secondary ligands could co-regulate coordination polymer with interesting properties, providing a constructive guidance when synthesizing versatile topologies with the same organic spacer but a different architecture. [ABSTRACT FROM AUTHOR]

Three new solvent-directed three-dimensional (3D) lead(ii) coordination polymers, [Pb2(L)2]n (1), [Pb3(L)3]n (2) and [Pb(L)]·H2O (3) [H3L = 2-(pyridine-2-yl)-1H-imidazole-4,5-dicarboxylic acid], have been synthesized solvothermally. As influenced by different solvent systems, compounds 1 and 3 exhibit varying architectures from a multi-nodal 3,3,4,4-connected to a uninodal 3-connected net, while 2 with helices represents a binodal 3,4-connected topological net. Moreover, 3 possesses a micropore which is decorated with pyridyl systems and uncoordinated carboxylate oxygen atoms. In addition, the small-sized and highly polar pores enable 3 to attract CO2 strongly, leading to a high sorption heat for CO2 and significant selectivity for CO2 over H2 and N2 at 293 K. The luminescent behaviors and emissive lifetimes of 1–3 are also discussed. [ABSTRACT FROM AUTHOR]