Search

Metal–organic frameworks with tunable functional groups like solid-solution have received considerable interest. In this paper, a crs-type structure built of [Zn3(OH)(dmtrz)3] triazolate-trinuclear and [Zn2(COO)4] paddlewheel units, linked by 3,5-dimethyl-1,2,4-triazolate (dmtrz) and isophthalate (ipa) ligands (named as MAC-4-A), has been used as a prototype framework. Four types of functional groups (B: 5-hydroxyisophthalate, C: 5-aminoisophthalate, D: 5-ethoxyisophthalate, and E: 5-acetamidoisophthalate) have been integrated into the framework, giving isostructures of MAC-4-B to E, respectively. Then, by the solid-solution framework approach, four group samples are prepared, which are MAC-4-AB-x, MAC-4-AC-x, MAC-4-AD-x, and MAC-4-AE-x (x denoted as the ratio of functional ligands in the framework, x = 0.3, 0.5, 0.7), and their CO2 and N2 adsorptions have been studied. Our results revealed that the CO2 capacity is enhanced with the increase of functional groups and then decreases, showing a maximum uptak...

Two metal–organic frameworks containing a geometrically spin-frustrated trinuclear-triangular copper cluster ([Cu3O]) have been successfully isolated, which are {[Cu4.5(μ3-OH)(dmtrz)3(m-bdc)2.5(H2O)2(CH3OH)(DMF)]·DMF·5H2O}n (MAC-8) and {[Cu5(μ3-OH)(dmtrz)3(bdc)3(H2O)4]·3H2O}n (MAC-9) (Hdmtrz = 3,5-dimethyl-1H-1,2,4-triazole, H2m-bdc = 1,3-benzenedicarboxylic acid, H2bdc = 1,4-benzenedicarboxylic acid, DMF = N′,N-dimethylformamide). Magnetic and gas adsorption studies revealed the successful combination of strong antiferromagnetic properties (Jav = −106.6 and −113.7 cm–1 for [Cu3O] in MAC-8 and MAC-9, respectively) and high surface areas (1058 m2/g for MAC-8 and 1242 m2/g for MAC-9) in both of the structures. Further structural studies revealed that the high surface areas could be ascribed to the unique two-dimensional hexagonal pattern of [Cu3(O)] clusters, in which the [Cu3(O)] clusters are connected to each other in an end-end fashion via mononuclear copper ions/paddle-wheel units.

Two novel porous metal–organic frameworks {Zn7(btc)4(dmtrz)2(H2O)5}n (1) and {[Zn6(btc)4(dmtrz)3]·3H3O·2H2O}n (2) (H3btc = 1,3,5-benzenetricarboxylic acid, Hdmtrz = 3,5-dimethyl-1H-1,2,4-triazole) have been solvothermally synthesized. Single-crystal structure analysis reveals that both structure 1 and 2 contain special triazole-carboxylate shared paddle-wheel units. The crucial factors to the assembly of such paddle-wheel units are discussed. Gas adsorption studies suggest that 2 is a potential microporous material for adsorptive separation of CO2 over N2.

Three porous metal−organic frameworks have been constructed from the new developed C3-symmetric hexacarboxylic acid 3,3′,3′′,5,5′,5′′-benzene-1,3,5-triyl-hexabenzoic acid (H6BHB) of different NaCl- and Al2O3-type topologies. The activated metal−organic frameworks (MOFs) exhibit permanent porosities as revealed in their gas and vapor adsorption isotherms, highlighting the promise of this new ligand for the construction of porous MOFs for gas storage and separation.

Two novel metal−organic frameworks (MOFs), Cu(3,4′-bpdc)(H2O)·DMF·2H2O (1) and Cu(3,4′-bpdc)(H2O)·2DMF·4.5H2O (2), have been solvothermally synthesized by the reaction of a unsymmetrically substituted carboxylate ligand 3,4′-biphenyldicarboxylic acid (3,4′-bpdc) and Cu(NO3)2·2.5H2O. X-ray crystal structural analyses reveal that both MOFs possess the binuclear paddle-wheel units [Cu2(O2CR)4], which are linked by the biphenyl connectors, to give two different three-dimensional (3-D) frameworks. The structural diversities are due to the different coordinated arrangements of the two distinct carboxylate groups. In 1, the noncentral symmetrical A−A−B−B arrangement leads to an uncommon twisted Cu-paddlewheel unit, which favors a tetrahedral configuration to generate a 3-fold interpenetrating 3-D framework with a diamond topology. In 2, the paddle-wheel unit constructed by the central symmetrical A−B−A−B arrangement of the ligand acts as a square-planar 4-connected node to give a 2-fold interpenetrating 3-D fram...

Six zinc phosphonocarboxylate hybrid materials, namely, Zn2(pbc)2·2Hdma·DMF·H 2 O (1), Zn( 2 (pbc) 2 ·H 2 teta·H 2 O (2), Zn(pbc)·H 3 O (3), Zn 4 (pbc) 3 ·HTEA (4), Zn 3 (pbc) 2 (en) 2 (5), and Zn 3 (pbc) 2 (H 2 O) (6) (H 3 pbc = 4-phosphono-benzoic acid, DMF = N,N-dimethylformamide, dma = dimethylamine, teta = triethylene tetramine, TEA = triethylamine, en = et thylenediamine) have been synthesized using organic amines as structure-directing agents under mixed-solvothermal condition. These new compounds have been characterized by X-ray single-crystal diffraction together with infrared (IR) spectroscopy, thermogravimetric (TG) analysis, and powder X-ray diffraction (XRD). In structures 1 and 2, the double crankshaft chains constructed by the comer-sharing of ZnO 4 and CPO 3 tetrahedra are cross-linked by the organic moieties of the ligands into three-dimensional (3-D) structures with GIS (gismondine) and GIS-related zeolite topologies. In structure 3, the connectivity between ZnO 4 and CPO 3 results in inorganic (4.6.12) sheets, which are pillared by the benzoic acid group -C 6 H 5 -COO- into a 3-D open framework structure with zeolitic SOD (sodalite) topology. Structures 4-6 are pillar-layered structures where the Zn-O-P layers show different configuration due to the directing effect from different organic amines and solvents employed during the synthesis. The results show that the amines and organic solvents acting as structure-directing agents along with control of reaction condition are effective in achieving varieties of zinc phosphonocarboxylate structures.