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Using a triazole carboxylic ligand (H2L = 4-(1H-1,2,4-triazol-1-yl) isophthalic acid), four water-stable lanthanide metal-organic frameworks (Ln(III)-MOFs) (1-Ln, Ln(III) = Tb, Eu, Dy, and Sm), [Ln(L)(HL)(H2O)2], where the deprotonated H2L ligands have two different coordination modes: L2− and HL− [(a): η2μ2χ2, η2μ1χ2; (b): η2μ1χ2], have been synthesized by solvothermal reaction and characterized by elemental analysis, FT-IR spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Single-crystal X-ray diffraction analyses show that Ln(III)-MOFs are isostructural with 2D-layered structures with uncoordinated carboxylic and triazole groups. The luminescent properties of 1-Tb in aqueous solution containing different cationic solutions and small organic solvents have been explored under ultraviolet irradiation at room temperature. The high quenching constant KSV values and low detection limits indicate that 1-Tb exhibits extremely high detection sensitivity and selectivity toward Fe3+ ions and nitrobenzene; 1-Tb can keep its original network and be reused after the sensing experiments, which provide us with an optical material for detecting Fe3+ ions and nitrobenzene. Magnetic studies show that antiferromagnetic exchange interactions exist between Dy(III) ions in 1-Dy. [ABSTRACT FROM AUTHOR]

By using an asymmetrical rigid pentacarboxylic acid ligand, 2,4-di(3′,5′-dicarboxylphenyl)benzoic acid (H5L), four new three-dimensional (3D) metal–organic frameworks (MOFs), namely {[Cu2(HL)(H2O)2]·2DMF·2H2O}n (1), {[Co2(L)(DMA)]·H2N(Me)2}n (2), {[Co2(L)(H2O)]·H2N(Me)2}n (3), {[Mn2(L)(DMF)(H2O)]·H2N(Me)2}n (4), were solvothermally synthesized. H5L in 1–4 shows different coordination modes and can easily form various metal clusters (secondary building units, SBUs) in the final structures. 1 is a 3D porous framework with a (4,4)-connected pts topology based on the [Cu2(COO)4] paddlewheel SBU, wherein six SBUs are connected by twelve HL4− to get an unprecedented Cu12 hendecahedron nanocage. 2–4 possess similar dinuclear [M2(COO)5] SBUs (M = Co, Mn), which are further extended by L5− to give rise to 3D frameworks with the uncommon (5,5)-connected nia-5,5-P21/c and bnn topologies. In addition, the desolvated framework of 1 contains polar channels decorated with uncoordinated carboxylate groups, leading to selective adsorption for CO2 over CH4 at 195, 273 and 298 K. Moreover, the magnetic properties of 1–4 show that there exist antiferromagnetic interactions between metal ions. [ABSTRACT FROM AUTHOR]

By treating a semirigid 5-oxyacetate isophthalic acid (H3OAIP) ligand with MnSO4/CoSO4/CdSO4 under solvothermal conditions, three isostructural cluster organic frameworks, [M2(OH)(OAIP)(DMA)] ⋅H2O (M=Mn2+ ( 1), Co2+ ( 2), Cd2+ ( 3); DMA= N,N′-dimethylacetamide) were constructed. The three complexes contain novel eight-connected tetranuclear M4(OH)2(COO)6(OCH2COO)2 clusters with the unique hexagonal bipyramidal configuration, which are extended by four-connected OAIP linkers to form an uncommon (4,8)-connected alb-4,8-Cmce topology based on (3,6)-connected kgd sublayers. Both 1 and 2 showed significant antiferromagnetic interactions between the intracluster metal ions, whereas 3 revealed strong blue photoluminescence. [ABSTRACT FROM AUTHOR]

Two novel complexes, {[Cd 3 (L) 2 (H 2 O) 2 ]·(H 2 O) 4 } n (1) and {[Mn(HL)(H 2 O) 2 ]·(H 2 O)} n (2), which are synthesized by the reaction of 3-(2, 4-dicarboxyphenyl)-4-carboxypyridine ligand with cadmium and manganese metal ions under the solvothermal method. The complex 1 is a 3D framework based upon trinuclear [Cd 3 (μ 2 -COO) 4 (μ 1 -COO) 4 (N) 2 ] SBUs, and the complex 2 is a one-dimensional metal oxygen chain based upon binuclear [Mn 2 (μ 2 -COO) 2 (μ 1 -COO) 2 (N) 2 ] SBUs. The solid fluorescence analysis of complex 1 reveals that the emission peak of 451 nm when its excitation peak is 336 nm. The fluorescence detection experiments of complex 1 showed that Fe3+, Cr 2 O 7 2− and CrO 4 2− can effectively to be detected. Furthermore, their limits of detection are 1.47 × 10−3 M, 1.31 × 10−3 M and 1.25 × 10−3 M, respectively. It has good recovery properties as a potential multifunctional fluorescence sensor. Besides, the quenching mechanism of fluorescence sensing is also discussed. In addition, the magnetic studies of complex 2 show strong antiferromagnetic interactions between its neighboring Mn(II) ions. [Display omitted] • Two novel stable complexes were constructed based on particular trinuclear and binuclear metal clusters. • Complex 1 shows high selectivity and sensitivity to detect Fe3+, Cr 2 O 7 2− and CrO 4 2− ions with low detection limit. • Complex 2 possesses antiferromagnetic interaction between its Mn (II) ions. [ABSTRACT FROM AUTHOR]

• Two novel 2D MOFs based on diverse metal-oxygen chains with high open metal sites. • Zn-MOF possesses good selectivity and sensitivity to detect Fe3+ and Cr 2 O 7 2− ions with low detection limit. • The variable-temperature susceptibility of Mn-MOF indicates antiferromagnetic interaction between the Mn(II) ions. In this paper, two novel two-dimensional MOFs were synthesized by solvothermal reaction of 2,4-di(2′,5′-dicarboxylphenyl)benzoic acid ligand and Zn(Ⅱ) and Mn(Ⅱ) metal ions: {[Zn 2 (HL)(H 2 O)(DMF) 2 ]·(H 2 O)·(DMF)} n (1), {[Mn 2 (HL)(H 2 O)(DMF) 2 ]·(H 2 O)·(DMF)} n (2). Complexes 1 and 2 are unique two-dimensional skeletons with particular metal-oxygen chains in their structures. The solid-state luminescence spectrum of complex 1 shows that its maximum emission peak is 448 nm. Further fluorescence studies of complex 1 show that it can efficiently detect Fe3+ and Cr 2 O 7 2− in aqueous solution with a detection limit of 4.1 × 10−4 M and 2.7 × 10−4 M respectively, and has good recycling performance, so it is a potential bifunctional fluorescent probe material. The mechanism of fluorescence sensing quenching was also investigated in detail. Furthermore, magnetic studies have shown that there is an antiferromagnetic interaction between Mn(II) ions of complex 2. [Display omitted] [ABSTRACT FROM AUTHOR]

Seven new complexes based on the bifunctional ligand were synthesized under hydro(solvo)thermal conditions. 1 – 7 adopts different coordination modes and generates diverse 1D or 2D structures. • The L2−/HL− ligand in 1 – 7 adopts different coordination modes and generates diverse structures. • Compound 1 shows highly selective and sensitive response to Fe3+. • Compound 1 shows highly selective sensitivity for Cr2O 7 2− and MnO 4 2−. Seven new complexes based on 4-(3-carboxyl-1,2,4-1H-triazol-1-yl)benzoic acid (H 2 L), namely [Zn(L)(H 2 O) 2 ] n (1), [Cd(L)(H 2 O) 2 ] n (2), [Pb(HL) 2 ] n (3), [Pb(L)(H 2 O)] n (4), [Cu(L)(H 2 O) 2 ] n (5), [Co(L)(H 2 O) 2 ] n (6) and [Mn(L)(H 2 O) 2 ] n (7), were synthesized by employing different center metal ions and a imidazol-carboxyl bifunctional ligand (H 2 L) under hydro(solvo)thermal conditions. The L2−/HL− ligand in 1 – 7 adopts different coordination modes and generates diverse 1D or 2D structures. The luminescent and magnetic properties of seven complexes were investigated in detail. Moreover, complex 1 shows high selectivity for Fe3+, Cr 2 O 7 2− and MnO 4 − ions, indicating that 1 can be an excellent candidate for luminescence sensing. In addition, complexes 5 , 6 and 7 demonstrate antiferromagnetic interactions. [ABSTRACT FROM AUTHOR]