Dan Tian

A luminescent metal–organic framework demonstrating ideal detection ability for nitroaromatic explosives

A 3D metal–organic framework, [NH2(CH3)2]2[Cd17(L)12(μ3-H2O)4(DMF)2(H2O)2]·solvent (1), has been constructed with a π-electron rich aromatic ligand 2,4,6-tris[1-(3-carboxylphenoxy)ylmethyl]mesitylene (H3L) and d10 configuration metal ion Cd2+ under solvothermal conditions. The crystal structure reveals that complex 1 consists of hexanuclear and trinuclear cadmium building units, which are further bridged by the multicarboxylate ligands to give a (3, 6, 12)-connected topological net. This complex exhibits strong ligand originated photoluminescence emission, which is selectively sensitive to electron-deficient nitroaromatic explosives (nitrobenzene, 4-nitrotoluene, 1,4-dinitrobenzene, 1,3-dinitrobenzene and 2,4-dinitrotoluene). This property makes complex 1 a potential fluorescence sensor for these chemicals.

A Mixed Molecular Building Block Strategy for the Design of Nested Polyhedron Metal–Organic Frameworks

A mixed molecular building block (MBB) strategy for the synthesis of double-walled cage-based porous metal-organic frameworks (MOFs) is presented. By means of this method, two isostructural porous MOFs built from unprecedented double-walled metal-organic octahedron were obtained by introducing two size-matching C3 -symmetric molecular building blocks with different rigidities. With their unique framework structures, these MOFs provide, to the best of our knowledge, the first examples of double-walled octahedron-based MOFs.

MOF-Derived Porous Co3O4 Hollow Tetrahedra with Excellent Performance as Anode Materials for Lithium-Ion Batteries

Porous Co3O4 hollow tetrahedra were prepared through the thermolysis of metal-organic frameworks and presented reversible capacities of 1196 and 1052 mAh g(-1) at 50 and 200 mA g(-1) after 60 charge/discharge cycles, respectively. Such excellent performances stem from the well-defined hollow structure of Co3O4 tetrahedra.

A series of complexes based on biphenyl-2,5,2′,5′-tetracarboxylic acid: syntheses, crystal structures, luminescent and magnetic properties

Five new metal complexes based on H4bptc: {[Cu2(bptc)(H2O)6]·11H2O}n (1), {[Ni2(bptc)(H2O)6]·11H2O}n (2), {[Co2(H2bptc)2(4,4′-bpy)2(H2O)2]·4H2O}n (3), [Ni2(bptc)(2,2′-bpy)2(H2O)6]·2H2O (4), [Zn2(bptc)(2,2′-bpy)2(H2O)6]·3H2O (5) (bptc = biphenyl-2,5,2′,5′-tetracarboxylic acid, 2,2′-bpy = 2,2′-bipyridine, 4,4′-bpy = 4,4′-bipyridine) have been synthesized and structurally characterized by elemental analysis, IR spectra, powder X-ray diffraction, thermogravimetric analysis and X-ray crystallography. Complex 1 features a 2D sheet structure with (4, 4) grid units. The Cu(II) center in 1 is penta-coordinated in a square-pyramidal geometry. Complex 2 is isostructural with 1 excluding the metal ions. Complex 3 shows a 2D layer structure with rectangular windows. There exist parallel left- and right-handed helical chains in adjacent 2D sheets in complexes 1–3. Complex 4 exhibits a 3D supramolecular structure with a butterfly-shaped unit cell. Complexes 5 and 4 are isomers excluding the lattice water molecules. The non-covalent interactions (O–H⋯O, C–H⋯O, C–H⋯π and π⋯π interactions) extend complexes 1–5 into 3D supramolecular networks. In addition, the photoluminescent properties for 1–5 and magnetic properties for 1, 3 have been investigated, respectively. Complexes 1 and 3 exhibit weak antiferromagnetic behaviour.

Li-ion storage and gas adsorption properties of porous polyimides (PIs)

In this work, three polyimides (PIs) are successfully synthesized by the condensation reaction of an aromatic triamine with three difunctional aromatic dianhydrides. These materials show electrochemical lithium ion storage properties as cathodes for lithium-ion batteries. The aromatic dianhydride monomers are found to have significant effects on their performances. In addition, the polymer PI-1 shows narrow micropore size distributions and selective adsorption of CO2 over CH4 and N2. Furthermore, PI-1 exhibits a high Qst value (11.7 kJ mol−1) for H2 adsorption.

Copper(II) and nickel(II) coordination polymers assembled from 2,4-dibenzoylisophthalic acid and different N-donor co-ligands: syntheses, crystal structures, and magnetic properties

Four new coordination polymers based on 2,4-dibenzoylisophthalic acid and different N-donor auxiliary co-ligands, {Cu2L2(4,4′-bpy)}n (1), {Ni2L2(4,4′-bpy)}n (2), {[Cu10(L)8(bbi)(μ3–OH)4(H2O)6]·4H2O}n (3) and {[CuL(bth)(H2O)]·H2O}n (4) (H2L = 2,4-dibenzoylisophthalic acid, 4,4′-bpy = 4,4′-bipyridine, bbi = 1,1′-(1,4-butanediyl)bis(imidazole) and bth = 1,6-bis(1,2,4-triazol-1-yl)hexane), have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction, elemental analysis, IR spectroscopy, UV-Vis spectra, powder X-ray diffraction and thermogravimetric analysis. Complexes 1 and 2 are isostructural and crystallized in the chiral space groupP3221. They both possess three-dimensional (3D) coordination frameworks with 6-connected (44·510·7) topology that are incorporated left-handed helices and right-handed double helices substructures based on M(II) (M = Cu, Ni) paddle-wheel clusters. Complex 3 exhibits a 3D (4,5)-connected network with (44·62) (44·66) topology, in which dinuclear Cu2(CO2)4 clusters act as 4-connected nodes and tetranuclear [Cu4(μ3–OH)2]6+clusters serve as 5-connected nodes. Complex 4 shows a two-dimensional (2D) parallelogrammic network with (4,4) topology. The magnetic properties for 1–3 have been investigated and exhibited antiferromagnetic interaction.

A three-dimensional metal–organic framework for selective sensing of nitroaromatic compounds

A 3D metal–organic framework [NH2(CH3)2][Cd6(L)4(DMF)6(HCOO)](DMF = N,N-dimethylformamide) (1) has been synthesized using a tripodal ligand H3L (2,4,6-tris[1-(3-carboxylphenoxy)ylmethyl]mesitylene). The obtained complex exhibits a 3D framework containing hexanuclear {Cd6} building units formed by two trinuclear {Cd3} clusters that are connected via HCOO− anions. For complex 1, the participation of the fluorescent ligand H3L not only gives rise to a strong photoluminescence emission as expected, but more interestingly, that ligand originated characteristic band could be quenched selectively by nitrobenzene with a low detection limit, showing its potential as a highly sensitive and selective sensor for nitrobenzene. Based on an electron transfer quenching mechanism, the fluorescence sensing ability of 1 is also applicable for other electron-deficient nitroaromatic compounds with high selectivity and sensitivity, i.e., 1,4-dinitrobenzene, 1,3-dinitrobenzene, 2,4-dinitrotoluene, and 4-nitrotoluene, suggesting...

Edge-directed assembly of a 3D 2p–3d heterometallic metal–organic framework based on a cubic Co8(TzDC)12 cage

A three-dimensional (3D) heterometallic metal–organic framework containing cubic-like cages, namely {[Co3Na6(TzDC)4(H2O)6]·7H2O}n (1) (H3TzDC = 1,2,3-triazole-4,5-dicarboxylate), has been synthesized by the edge-directed self-assembly of TzDC3−, Co2+ and Na+ ions. Crystal data reveals that one hydrous Co2+ cation is embedded in the central cavity of a cubic-like cage [Co8(TzDC)12]20− with eight Co2+ cations as the corners and twelve TzDC3− ligands as the edges. The cages are further bridged by Na+ ions to result in a 3D framework with pcu topology. Magnetic investigation indicates that besides the spin–orbit coupling of Co2+ ions, an antiferromagnetic exchange interaction was found to exist between the Co2+ ions in the Co9 cluster of 1.

Syntheses, crystal structures, and magnetic properties of two new manganese(II) complexes based on biphenyl-2,5,2′,5′-tetracarboxylic acid

Two new complexes, [Mn(H2bptc)(2,2′-bpy)2] · 2H2O (1) and [Mn3(Hbptc)2(2,2′-bpy)3(H2O)8] · 2H2O (2) (H4bptc = biphenyl-2,5,2′,5′-tetracarboxylic acid, 2,2′-bpy = 2,2′-bipyridine), have been synthesized under hydrothermal conditions. Their structures have been characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, powder X-ray diffraction, and thermogravimetric analyses. Complexes 1 and 2 are both linked into 3-D supramolecular networks by non-covalent interactions (O–H ··· O, C–H ··· O, C–H ··· π, and π ··· π). Complexes 1 and 2 exhibit weak antiferromagnetic interactions.

Three Novel Polymeric CoII/CuII Complexes Assembled from 5-Nitro-1,2,3-benzenetricarboxylate and 4,4'-Bipyridine: Syntheses, Crystal Structures, and Magnetic Properties

To investigate the coordination behaviour of tricarboxylate ligands that always induced the formation of intriguing metal organic frameworks, three CoII/CuII complexes constructed with bi-/tri-nuclear secondary building units (SBUs), namely CoII3(O2N-btc)2(4,4′-bpy)3(H2O)2 (1), [CuII3(O2N-btc)2(4,4′-bpy)2(H2O)2]·2H2O(2) and [CuII5(O2N-btc)2(O2N-btcH)2(4,4′-bpy)2(μ2 -OH2)2(H2O)8]·4H2O(3) (O2N-btcH3 = 5-nitro-1,2,3-benzenetricarboxylate, 4,4′-bpy = 4,4-bipyridyl), were hydrothermally synthesized using O2N-btcH3 and 4,4′-bpy as ligands. Complexes 1 and 2 exhibit the 3D framework constructed from a binuclear [M2(COO)2] (M = CuII and CoII) unit and a mononuclear MII unit, displaying (4·6·8)2(64·82) (42·68·83·102) and (4·6·8)2(62·84) (42·62·810·12) topology, respectively. Complex 3 displays an interesting 2D ladder-layered network constructed from a trinuclear [Cu3(μ2-OH2)2] unit and a mononuclear CuII unit as the linking nodes, showing (42.6)2(46.66.83) nets. These compounds are well characterized by elemental analysis, FTIR, thermogravimetric analysis and powder X–ray diffraction. The direct current magnetic susceptibility measurements were carried out to study their magnetic properties.