Xiao-Yin Zhang

Syntheses, structural diversity, magnetic properties and dye absorption of various Co(II) MOFs based on a semi-flexible 4-(3,5-dicarboxylatobenzyloxy)benzoic acid

Five novel Co(II) metal–organic frameworks (MOFs) constructed from semi-flexible 4-(3,5-dicarboxylatobenzyloxy)benzoic acid (H3L), namely {[Co1.5(HL)(4,4′-bidpe)2(H2O)]·3H2O}n (1), {[Co3(L)2(4,4′-bibp)3(μ2-O)2]·2H2O}n (2), {[Co(HL)(1,3-bitl)]·(1,4-Diox)}n (3), [Co2(HL)2(3,5-bipd)2]n (4), and {[Co(HL)(tib)]·0.5H2O·NMP}n (5) (4,4′-bidpe = 4,4′-bis(imidazolyl)diphenyl ether, 4,4′-bibp = 4,4′-bis(imidazol-1-yl)biphenyl, 1,3-bitl = 1,3-bis(1-imidazoly)toluene, 3,5-bipd = 3,5-bis(1-imidazoly)pyridine, and tib = 1,3,5-tris(1-imidazolyl)benzene), were synthesized under solvothermal conditions and further characterized by elemental analysis, IR spectra, powder X-ray diffraction (PXRD), thermogravimetric (TG) analysis and single-crystal X-ray diffraction. Different architectural topologies have been generated by adjusting the N-donor ligands. Single-crystal X-ray diffraction analysis reveals that complex 1 shows a rare 1D → 2D polyrotaxane network. Complex 2 possesses an unprecedented 2-nodal (3,10)-connected 3D framework with a Schlafli symbol of (43)2(46·632·83)(43)2. When the 2-connected points (H3L and 1,3-bitl ligands) are not calculated, complex 3 shows a hcb uninodal 3-connected 2D network with the Schlafli symbol (63), which further constructs a 3D supramolecular structure through O–H⋯O hydrogen bonds; while the 2-connected points are taken into account, complex 3 exhibits an unprecedented 3-nodal (2,2,4)-connected network. Complex 4 presents an unprecedented 2-nodal (3,5)-connected 3D framework with a (4·62)(4·66·83) topology, while complex 5 exhibits another unprecedented 2-nodal (3,5)-connected 2D framework with a (42·67·8)(42·6) Schlafli symbol and shows 2D → 3D supramolecular structure through O–H⋯O hydrogen bonds. Meanwhile, the magnetic properties of complexes 2 and 4 are discussed. Moreover, the dye adsorption and mechanism studies indicate that the pore size, the uncoordinated O atoms in carboxyl groups and the uncoordinated carboxyl groups of the MOFs have significant effects on the dye adsorption capacity.

Two 3D ZnII Metal–Organic Frameworks with 3- and 8-Fold Interpenetration: Syntheses, Structures, Photodegradation, and Photoluminescent Properties

Two novel coordination polymers, namely {[Zn(sbdc)(bmib)]·0.4H2O}n (1) and {[Zn(sbdc)(bibd)]·DMF}n (2) (H2sbdc = 4,4′-stilbenedicarboxylic, bmib = 1,4-bis(2-methylimidazol-1-yl)butane, bibd = 1,1′-(1,4-butanediyl)bis(imidazole), DMF = N,N-dimethylformamide), have been acquired under solvothermal conditions, and have been characterised by elemental analysis, infrared spectra, thermogravimetric analysis, and single-crystal X-ray diffraction (XRD). Single-crystal XRD analysis reveals that 1 shows eight-fold interpenetrating 3D frameworks with a four-connected (66) sqc6 topology and 2 displays four-connected three-fold interpenetrating 3D frameworks. The flexible N-donor ligands play an important role in the construction of the final topological structures for 1 and 2. Furthermore, 1 and 2 exhibit good photodegradation capability and photoluminescence properties.