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Two isomorphic lanthanide compounds {[Ln(ddpp)(H 2 O)]·CH 3 CN} n (Ln = Eu and Gd, H 4 ddpp = 2,5-di(2',4'-dicarboxylphenyl)pyridine) were synthesized. Complex 1-Eu displays ultrahigh acid-base stability and thermal stability. Furthermore, luminescence measurements revealed that 1-Eu could detect quinolone antibiotics with an ultralow limit of detection in aqueous solution. The ratiometric probe properties for sensing antibiotics could be attributed to the incompletely sensitized Eu 3+ ion of the ligand. Remarkably, it is interesting that 1-Gd exhibits excellent tetracycline degradation properties under visible light. Ultraviolet-visible diffuse reflectance spectroscopy and valence band X-ray photoelectron spectroscopy were carried out to investigate the photodegradation mechanisms. Moreover, a rational explanation for the fluorescent probe and photocatalysis behavior of these two complexes was also discussed with the assistance of density functional theory calculations.

The highly porous luminescent metal-organic frameworks (MOFs) can act as fluorescent probes for the detection of nitro compounds and can also serve as containers and energy transfer platforms to construct the host-guest systems. Herein, two new three-dimensional MOFs with high porosity were prepared successfully by the electron-rich tetrakis(4-pyridylphenyl)ethylene (tppe) as ligands. Compound 1 shows the high sensitivity and selectivity toward nitro-antibiotics in an aqueous media, particularly showing the best detection efficiency for furazolidone (FZD) among the reported luminescent sensors. The highly efficient fluorescence quenching toward FZD may be attributed to the electron and energy transfer. Compound 2 has naphthalene-2,7-dicarboxylic acid (2,7-npd) and tppe as dual linkers, and the energy transfer between 2,7-npd and tppe leads to the emission band in a large scale. It is worth noting that the single-phased white-light materials can be obtained by the in situ encapsulation of different concentration of sulforhodamine 101 (SR101) into compound 2 matrix.

A stainless steel fiber was coated with a gate-opening controlled metal-organic framework ZIF-7 via a sol-gel method and applied to the solid-phase microextraction of aldehydes (hexanal, heptanal, octanal, nonanal, decanal) from exhaled breath by lung cancer patients. The effects of temperature and time on the sorption and desorption were optimized. Under optimum condition, the modified fiber displays enrichment factors (typically ranging from 300 to 10,000), low limits of detection (0.61-0.84 μg L -1 ), and wide linear ranges of hexanal, heptanal (5-500 μg L -1 ) and octanal, nonanal, decanal (10-1000 μg L -1 ). The high extraction capability for aldehydes is thought to result from (a) the combined effects of the large surface area and the unique porous structure of the ZIF-7, (b) the hydrophobicity and gate-opening effect of the sorbent, (c) the high selectivity of the window, and (d) the presence of unsaturated metal-coordination sites. The coated fiber is thermally stable and can be re-used >150 times. The relative standard deviation (RSD) for six replicate extractions using a single fiber ranged from 1.4-15.3% for intra-day and 2.4-16.1% for inter-day. The fiber-to-fiber reproducibility for three fibers prepared in parallel was in the range of 2.4-12.6% (RSD). The method was applied to the extraction of aldehydes from real samples and to the quantitation by gas chromatography. Recoveries from spiked samples ranged from 84 to 113%. Graphical abstract A metal-organic framework ZIF-7 coated stainless steel fiber was prepared via sol-gel method. The self-made fiber was applied in the solid phase microextraction of aldehydes from exhaled breath of lung cancer patients.

Lanthanide metal–organic framework (Ln-MOF) based phosphors for light-emitting diodes (LEDs) play an important role in the fields of solid-state lighting and display. The rational design of organic antennae to address the drawback of low extinction coefficients of the lanthanide ions is highly desired. In this work, we provide a new design strategy to achieve an energy transfer molecule with a through-space conjugated folded structure, which can strengthen the skeleton rigidity and facilitate triplet state energy transfer. Consequently, one U-type π-conjugated molecule 2,6-bis(3,5-dicarboxylphenoxy) pyridine (H4L) was selected as a light gatherer to sensitize lanthanide ions for the construction of Ln-MOFs [Ln(HL)(H2O)3]n (Eu-MOF and Tb-MOF), which exhibit a long-lived luminescence lifetime (0.88 ms for Eu-MOF and 1.31 ms for Tb-MOF) and high quantum yields (50.87% for Eu-MOF and 85.64% for Tb-MOF). Furthermore, a white LED device with a colour rendering index (89) was fabricated using the mixture of Ln-MOFs with a commercial blue phosphor. [ABSTRACT FROM AUTHOR]

Developing high-performance fluorescent materials to detect toxic contaminants in water is of great importance due to heavy metal pollution which has aroused wide public concern. Herein, two robust lanthanide metal–organic frameworks {[Ln(L)(H2O)]·7H2O}n (1-Ln; Ln = Eu and Tb. H3L = 5-(3′,5′-dicarboxylphenyl)picolinic acid) were successfully constructed and structurally characterized. 1-Eu and 1-Tb are isomorphic and feature a three-dimensional highly porous pillared-layer framework. Notably, both 1-Eu and 1-Tb demonstrate good luminescence performance, and excellent water, thermal and chemical stability. Then, 1-Eu and 1-Tb were further utilized as multi-responsive fluorescent sensors for detection of Fe(III) and chromate ions in water with high sensitivity, fast response, high selectivity and excellent recycling usability. The detection limits toward Fe3+/CrO42−/Cr2O72− are calculated to be 0.67/0.53/0.32 μM for 1-Eu and 1.26/0.75/0.57 μM for 1-Tb, respectively, which are far below the maximum standard defined by the United States Environmental Protection Agency (EPA) for drinking water. Furthermore, the quenching mechanisms can be explained as the synergetic effect of the competitive absorption and energy-transfer between 1-Eu/1-Tb host and analyte ions. [ABSTRACT FROM AUTHOR]

A novel 2D zinc(II) metal–organic framework, formulated as [Zn(L)(H2O)]·H2O (1) (H2L = 4-(pyridine-4-yl) phthalic acid), has been successfully obtained under solvothermal conditions. This metal–organic framework (MOF) material exhibits efficient photocatalytic activity towards the degradation of organic dyes in the absence of any photosensitizer or cocatalyst. Its catalytic performance for rhodamine B (RhB) and methyl orange (MO) degradation was superior to most reported MOFs with a degradation efficiency of 98.5% for RhB and 83.8% for MO within 120 min in the absence of H2O2, which could be attributed to its high efficiency in generating ·O2− (an effective oxidant for the degradation of dyes). The possible mechanism of the reaction was discussed in detail. In addition, 1 shows stable catalytic efficiency after five reaction cycles, which indicates that 1 exhibits efficient catalytic activity and good reusability toward the degradation of organic dyes, enabling it to be a potential candidate for environmental governance. [ABSTRACT FROM AUTHOR]

A newlanthanummetal organic framework, formulated as [La(DPA)(HDPA)]n(1), (H2DPA = 3-(4-hydroxypyridinium-1-yl) phthalic acid) has been synthesized and structurally characterized by IR spectroscopy, elemental analysis, thermogravimetry, and single-crystal X-ray crystallography. The polymer features a three-dimensional (3D) networks containing La(III)-carboxylate ribbon double chains. The bulk purity of the materials of 1 was confirmed through the powder X-ray diffraction (PXRD) patterns. The photoluminescence property of polymer 1 has also been investigated. [ABSTRACT FROM PUBLISHER]

Abstract: The reactions in mixtures of water–ethanol between lanthanide salts and nitrogen N-hetrocyclic carboxylic acid, in the presence of ammonium oxalate, result in two interesting lanthanide–organic coordination polymers, formulated as, {[Sm4(Hmimda)4(μ4-C2O4)2·6H2O]·8H2O} i (1), [Eu4(Hmimda)4(μ4-C2O4)2·6H2O]·4H2O} n (2), (H3mimda=1H-2-methyl-4, 5-imidazole-dicarboxylic acid). The polymers 1 and 2 are isostructural, and are both built from zig-zag 1D chains constructed from Ln-Hmimda moieties bridged by oxalate, as the secondary building unit (SBU). The Hmimda ligand further is interconnected the 1D chains to form the 3D framework. Variable-temperature magnetic susceptibility measurements indicate that the μ4-k 4 O bridging fashion of oxalate results in the possible antiferromagnetic interactions occurring between the adjacent lanthanide(III) centers. The photo-luminescent and thermalgravimetric analyses of the polymers were also determined. [Copyright &y& Elsevier]

Two isostructural 3D europium metal–organic frameworks incorporating similar Eu-fluorine substituted carboxylate tectonics, {[Eu 4 (Mimda) 4 (Tfpa) 2 ·4H 2 O]} n ( 1 ) and {[Eu 4 (Pimda) 4 (Tfpa) 2 ·4H 2 O]} n ( 2 ) (Mimda = 2-methyl-1H-imidazole - 4, 5–dicarboxy acid, while Pimda = 2-propyl-1H-imidazole - 4, 5–dicarboxy acid and Tfpa = (3,4,5,6-tetrafluoro-1,2 phthalate acid) have been synthesized under the hydrothermal conditions. They have been systematically characterized by elemental analyses, IR spectra and PXRD patterns. Single crystal X-ray diffraction analysis reveals that each polymer possesses infinite rod-shaped chain consist of dinuclear Eu-carboxylate building units, which are further pillared by imidazole-dicarboxylate ligands to give rise to 3D open non-interpenetrated frameworks, featuring a (6, 4)-connected pseudo-primitive cubic (pcu) topology. Both two polymers exhibit efficiently sensitized red luminescence due to an energy transfer from substituted dicarboxylate ligand to Eu(III) ions in solid state. Polymer 1 also demonstrates tunable or switchable fluorescence signals in response to the different solvents. Moreover, the luminescent intensity of 1 is increased linearly with the increasing concentration of Pb 2 + cation in N , N -dimethyl formamide (DMF) suspension, while shows declining trend with Cd 2 + cation being introduced. [ABSTRACT FROM AUTHOR]

Two three dimensional (3D) Co(II) coordination polymers incorporating similar substituted imidazole-dicarboxylate and dipyridyl-type ancillary ligands pillared layer, namely, {Co 3 (mimda 3 − ) 2 (bpe) 3 ·3H 2 O} n ( 1 ) and {Co 3 (eimda 3 − ) 2 (bipy) 3 ·8H 2 O} n ( 2 ) (H 3 mimda = 1H-2-methyl-4,5-imidazole-dicarboxylic acid, while H 3 eimda = 1H-2-ethyl-4,5-imidazole-dicarboxylic acid, bpe = 1,2-di(4-pyridyl) ethylene and bipy = 4, 4′-bipyridine) have been successfully synthesized. Both polymers 1 and 2 have been characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, and thermogravimetric analysis (TGA). X-ray structural analysis reveals that they are nearly isostructural, possessing similar symmetry units based on trinuclear clusters, and further is propagated into a Kagomé-like lattice. The lattice consists of corner-sharing triangles of spins with magnetic coupling between the nearest neighboring Co(II) ions. Magnetic measurements revealed spin-canting-like antiferromagnetism behaviors for compounds 1 and 2 at lower temperature. The interaction in 1 is slightly stronger than that of 2 , which can be explained by the discrepancy of organic linker between the adjacent Co(II) centers. [ABSTRACT FROM AUTHOR]

The reactions in mixtures of lanthanide oxides and biphenyl-2,3,3′,5′-tetracarboxylic acid, in the presence of aqueous solution, result in two interesting lanthanide–organic coordination polymers, formulated as{[Eu(Hbptc)(H 2 O) 4 ]·H 2 O} n ( 1 ) and [Sm(Hbptc)(H 2 O) 3 ]} n ( 2 ), (H 4 bptc = biphenyl-2,3,3′,5′-tetracarboxylic acid). The polymers 1 and 2 are built from 2D corrugated layer. The 2D layers are further interconnected to form the 3D framework by hydrogen bonds between water molecules and carboxyl groups. Both the complexes 1 and 2 exhibit efficient sensitized luminescence in the visible region in the solid state based on characterization emission of europium(III) and samarium(III) ions, respectively. [ABSTRACT FROM AUTHOR]

Abstract: A 3D MOF {[Ni(H2O)6][Ni4L2(μ3-OH)2(H2O)2]}n (1) with a (4,8)-connected flu net is constructed by a butterfly-like tetranuclear [Ni4(μ3-OH)2(COO)8]2− anionic cluster and organic linker 2,3′,5,5′-biphenyl tetracarboxylic acid (H4L). The disordered [Ni(H2O)6]2+ cations fill in the free voids of anionic framework in 1. Magnetic susceptibility measurements indicate that complex 1 shows weak antiferromagnetic interactions. [Copyright &y& Elsevier]

Two new cobalt(II) clusters based 3D metal-organic frameworks (MOFs) [Co 2 (iBuOip) 2 (bpa) 2 (H 2 O)] (1) and [Co 5 (iBuOip) 4 (μ 3 -O)(bpp) 2 (DMF)(H 2 O) 3 ]·2H 2 O (2) (iBuOip = 5-i-butoxyisophthalate, bpp = 1,3-bis(4-pyridyl)propane and bpa = 1, 2-bi(4-pyridyl)ethane), were synthesized with 5-i-butoxyisophthalate and bpp/bpa mixture ligands. Compound 1 shows a 3D network constructed from both a dinuclear cluster and mononuclear Co(II) nodes. The mixture of triangular trinuclear and rhombus tetranuclear cluster nodes linked by 5-i-butoxyisophthalate and bpp give rise to a 3D pillared-layer structure of 2. The structural and topological differences of the two complexes demonstrate that the characteristics of the N-donor auxiliary ligands play significant roles in constructing the novel architectures of coordination polymers. Electrochemical measurements reveal that 2 modified electrode is catalytically active to oxygen evolution reaction with a lower overpotential of only 340 mV at 10 mA cm-2 in neutral solution. Two new cobalt(II) clusters based 3D metal-organic frameworks were successfully synthesized. The introduction of different N-donor auxiliary ligands can result in distinct spatial architectures. The MOFs show high catalytically active for oxygen evolution reaction. Image 1 • Two new cobalt(II) clusters based 3D metal-organic frameworks were successfully synthesized. • 1 shows a 3D network constructed from both a dinuclear cluster and mononuclear Co(II) nodes. • 2 is a 3D pillared-layer network based on the mixture of triangular trinuclear and rhombus tetranuclear cluster. • 2 modified electrode exhibits high catalytically active to oxygen evolution reaction with a lower overpotential of only 340 mV at 10 mA cm-2 in neutral solution. [ABSTRACT FROM AUTHOR]

A new metal-organic framework derived from Cu(II), 5-nitro-1,2,3-benzenetricarboxylic acid and a bis(triazolyl)propane is shown to be an efficient and recyclable heterogeneous catalyst for the highly selective enamination of β-ketoesters (I) (11 examples). [ABSTRACT FROM AUTHOR]