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Anionic metal–organic frameworks (MOFs) are beginning to have a great impact in the field of absorption and separation of ionic organic molecules due to the enhanced electrostatic interactions between their anionic frameworks and counter-ionic guests. Herein, the rational design and synthesis of two mesoporous anionic MOFs, [Zn3(ITTC)3](Me2 NH2)3·3DMF·H2O (1) and [Cd2(ITTC)3](Me2NH2)5·2DMF (2), where H3ITTC = 4,4′,4′′-(1H-imidazole-2,4,5-triyl) tribenzoic acid, is reported. Structural analysis revealed that both materials are anionic MOFs with a 2-fold interpenetrating three dimensional (3D) framework. The cross sectional area of the open one-dimensional rectangular channels is 31.7 Å × 15.6 Å for 1, of which the architecture is indicative of an unprecedented (3,3,4,5)-connection topology. For 2, the diameter of the open one-dimensional regular hexagonal channel is about 34.1 Å, decorated with uncoordinated carboxyl O atoms, and the framework exhibits a (3,4)-connected fcu network. Due to their anionic frameworks and bulky pore window sizes, both MOFs can be employed for absorbing and separating the cationic organic dye methylene blue (MB). The results reveal that both MOFs have better dye adsorption selectivity for MB, than for MO and SDI, because of charge and size-matching effects, enabling them to be potential candidates for use in environmental cleaning. By comparison, 2 presents superior selectivity and adsorptivity for cationic MB which depends on the presence of a basic functionalized pore surface. [ABSTRACT FROM AUTHOR]

Three new coordination polymers (CPs) based on Cu(II), namely {[Cu6(H2L)4(4,4′-bpy)6(H2O)2]·16H2O}n(1), {[Cu(H3L)(1,4-bib)]·3H2O}n(2), and {[Cu2(H2L)2(1,4-bib)2][Cu(1,4-bib)(H2O)2]}n·4nH2O(3) (H5L = 6-(3′,4′-dicarboxyphenoxy)-2,3,5-benzene tricarboxylic acid, 4,4′-bpy = 4,4′-bipyridine and 1,4-bib = 1,4-bis(1H-imidazol-1-yl)benzene) were synthesized under hydrothermal conditions and characterized. 1 adopts a three-dimensional structure and can be described with the point symbol {4·52}2{42·54·64·83·92}{5·104·12} whereas 2 shows a layered structure. 3 can be perceived as a complex salt of two coordination polymers: the cationic component [Cu(1,4-bib)(H2O)2]n2+ (3a) represents a chain polymer and the second anionic moiety [Cu2(H2L)2(1,4-bib)2]n2− (3b) corresponds to a 2D sub-structure. In the presence of H2O2, all complexes 1–3 act as efficient photocatalysts for the degradation of the dye methylene blue (MB). The effects of properties such as initial MB concentration, catalyst dosage, pH value, and H2O2 concentration on MB degradation were also investigated and analyzed in detail. Compounds 1–3 exhibit excellent structural stability during the catalytic process and can be reused at least three times. The hydroxyl radical (OH˙) and holes (h+) were confirmed as the main active species in the degradation process. [ABSTRACT FROM AUTHOR]

Six new Anderson-type polyoxometalate (POM)-based metal–organic complexes (MOCs), namely, {HCu(HPCAP)2[CrMo6(OH)6O18]}·2H2O (1), {Zn4(PCAP)2[CrMo6(OH)6O18]2(H2O)12}·4H2O (2), {Zn3(PCAP)2[CrMo6(OH)5O19](H2O)6}·6H2O (3), {Ni3(PCAP)2[NiMo6(OH)5O19](H2O)6}·8H2O (4), {Cu3(PCAP)2[AlMo6(OH)5O19](H2O)6}·6H2O (5), and {Co3(HPCAP)2[AlMo6(OH)6O18](H2O)10}[AlMo6(OH)6O18]·6H2O (6) (HPCAP = 3-(2-pyridinecarboxylic acid amido)pyridine), were constructed from diverse metal ions (CuII/ZnII/NiII/CoII), the HPCAP ligand and various Anderson-type POM anions under hydrothermal and solvothermal conditions and structurally characterized by single-crystal X-ray diffraction, IR spectroscopy, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). Crystal analysis shows that complex 1 has a 3D supramolecular structure based on the CrMo6 anions and the 1D metal–organic ribbon chains [Cu(HPCAP)2] via hydrogen bonds. Complex 2 is a 2D supramolecular layer composed of two kinds of dinuclear metal clusters of [Zn2(CrMo6)2] and [Zn2(PCAP)2]. Complexes 3–5 show similar 3D frameworks. In 3–5, [M1Mo6]3− (M1 = Cr for 3, Ni for 4, and Al for 5) anions are bridged by MII ions (M = Zn for 3, Ni for 4, and Cu for 5) to give a 1D M–M1Mo6 inorganic chain; the adjacent 1D inorganic chains are connected through two directions of [M2(PACP)2] rings to form a 3D framework. It should be noted that in complex 4, the NiMo6 anions are in situ generated from the NiII ion and Mo7O246− anions, which is rarely observed in POM-based MOCs. Complex 6 shows a 1D ladder-like supramolecular double chain, which is composed of 1D Co–AlMo6 inorganic chains, [Co2(HPCAP)2] dual-core rings and discrete AlMo6 polyanions interlinked by hydrogen bonding interactions. These structural diversities show that solvents play key roles in the construction of various architectures. All of the title complexes have excellent adsorption activities for the cationic dyes methylene blue (MB) and gentian violet (GV); in particular, complex 5 is capable of selectively adsorbing MB and GV from the mixtures of MB and MO and GV and MO, respectively. In addition, the electrochemical properties of complexes 1, 4, and 5 are also studied. [ABSTRACT FROM AUTHOR]

A homochiral three-dimensional framework material, [Cu7(4-bpt)6(CN)(H2O)] (1) (4-bpt = 3,5-bis(4-pyridyl)-1,2,4-triazole), has been successfully synthesized by solvothermal reaction, which is generated through an unusual spontaneous asymmetrical crystallization from achiral precursors, and its photocatalytic properties in degradation of organic dyes are also investigated. [ABSTRACT FROM AUTHOR]

Chalcogenolate clusters can be interlinked with organic linkers into semiconducting coordination polymers with photocatalytic properties. Here, discrete clusters of Cd8S(SPh)14(DMF)3 were interlinked with 4,4′-bipyridine into a one dimensional coordination polymer of [Cd8S(SPh)14(DMF)(bpy)]n with helical chains. A stepwise mechanism for the assembly of the coordination polymer in DMF was revealed by an ex situ dynamic light scattering study. The cluster was electrostatically neutral and showed a penta-supertetrahedral structure. During the assembly each cluster was interlinked with two 4,4′-bipyridine molecules, which replaced the two terminal DMF molecules of the clusters. In their solid-state forms, the cluster and the coordination polymer were semiconductors with wide band gaps of 3.08 and 2.80 ev. They photocatalytically degraded rhodamine B and methylene blue in aqueous solutions. The moderate conditions used for the synthesis could allow for further in situ studies of the reaction-assembly of related clusters and coordination polymers. [ABSTRACT FROM AUTHOR]