Jinghua Lv

High-efficiency photo- and electro-catalytic material based on a basket-like {Sr⊂P6Mo18O73} cage

A novel high-efficiency photo-/electro-catalyst based on phosphomolybdate (H4bth)[{Mn2(H2O)3} {Sr⊂P6Mo2VMo16VIO73}]·3H2O (1) (bth = 1,6-bis(triazole)hexane), has been hydrothermally synthesized and characterized by X-ray crystallographic analyses, FT-IR, UV-vis, TG-DTA, XRD, XPS, and the elemental analyses. Compound 1 is an eight-connected 2-D layer structure, which represents the highest-connected assembly of basket-type POMs. The compound exhibits universal high-efficient degradation ability for the azo dyes MB, RhB, and AP under UV and visible light irradiation. The catalyst has a long lifetime and can be recovered and reused with a slight loss of reactivity. The major photoreaction pathways of three dyes on the surface of catalyst 1 were detected by a series of radical trapping experiments. The result suggests that ˙O2−, ˙OH radicals and photogenerated h+ play different roles in the degradation process. The diffuse reflectivity spectrum provides essential evidences for the highly-efficient oxidation performance of basket-liked POMs. The compound also shows good bifunctional electrocatalytic behavior for oxidation of AA and reduction of NO2−.

The highest connected pure inorganic 3D framework assembled by {P4Mo6} cluster and alkali metal potassium

A 3D high connected pure inorganic framework based on {P4Mo6} cluster, [{K(H2O)}12{CoMo12VO24(OH)6(HPO4)4(PO4)4}] (1) has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, UV analysis and single crystal X-ray diffraction analyses. In compound 1, each basic unit {Co(P4Mo6)2} dimeric cluster uses its surface oxygen atoms (36) to attract 30 different-occupied potassium atoms at its periphery, which act as diverse bridge unit forming an centrosymmetric 18-connected open-framework with a (3343)2(364125664)(364845366213727869)(4)9 topology. Compound 1 represents the highest connection of the {P4Mo6}-based POMs up to now. Compound 1 shows bifunctional electrocatalytic activities toward not only reduction of nitrite and hydrogen peroxide, but also oxidation of biological molecules ascorbic acid (AA) ascribed to MoV-centers. In addition, compound 1 shows excellent photocatalytic activities for the degradation of methylene blue (MB).

Two extended Wells–Dawson arsenomolybdate architectures directed by Na(I) and/or Cu(I) organic complex linkers

Two extended Wells–Dawson arsenomolybdates, (imi)2[{CuI(imi)2}2{Na(imi)2}{AsIIIAs2VMo18O62}]·2H2O (1) and {CuI0.5(trz)}6 [{CuI0.5(trz)}6(As2Mo18O62)] (2), (imi = iminazole; trz = 1,2,3-triazole), are hydrothermally synthesized and extensively characterized. Compounds 1 and 2 contain a fully oxidized Dawson {As2Mo18O62}6− (abbreviated as {As2Mo18}) anion as the parent cluster unit. Compound 1 is a symmetric mono-arsenate capped anion cluster modified by two half occupancy {AsO3} units, which represents a new capping mode for Dawson clusters. The two adjacent mono-arsenate capped structures are linked by two {Na(imi)2} bridges to form a dimeric cluster, which, as a tetra-dentate ligand, further connects with adjacent dimers by four {Cu(imi)2} linkers to form an infinite ladder shaped chain. In compound 2, each classical Dawson cluster links six adjacent analogs by six {Cu0.5(trz)2} fragments forming an unprecedented 3D network via a unique belt-to-belt staggered pattern. This structure can be simplified as a 2,6-connected 3-D framework with {812·123}{8}3 topology. Compounds 1 and 2 represent the first 1-D and 3-D assemblies of Dawson-type arsenomolybdates, respectively. They display unique electrocatalytic behavior for the oxidation of ascorbic acid (AA) and reduction of NO2− as well as good photocatalytic properties for the degradation of the difficult-to-degrade dye AP under UV light.

The first 3D host–guest structure based on a three-fold interpenetrated Ag-pz coordination polymer network and Keggin-type aluminum tungstates with photo/electro-catalytic properties

A new 3D POM-based coordination polymer network, [{Ag5(pz)7}{AlW12O40}]·4H2O (1) (pz = pyrazine), has been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, UV-vis, XRD, TG, and single-crystal X-ray diffraction. In compound 1, 3-coordinated Ag3 and 4-coordinated Ag2 are alternately joined together to form a large decagon ring by sharing pz or “V”-like Ag4-pz bridges. Each large ring is connected with six adjacent rings via the edge-sharing modes resulting in an infinite 2-D layer. It is worth noting that the “Y”-shaped Ag1-pz segment is suspended on the ring through sharing pz with the Ag2-pz tetrahedron, which is an important linkage unit extending the 2-D layers to a three-fold interpenetrating Ag-pz network with (103·123) (103)(10)2(122·14) topology. The Keggin {AlW12} as inorganic ‘guest’ units are encapsulated into the channel of the Ag-pz framework to form a complex POMOF 3D network. In addition, compound 1 exhibits better electrocatalytic properties to reduce hydrogen peroxide and good photocatalytic activity for the degradation of rhodamine B (RhB), methyl orange (MO), methylene blue (MB) and azophloxine (AP).

1,4-Bis(imidazole)butane ligand and strontium(II) directed 1-D chains based on basket-type molybdophosphates and transition metal (TM) linkers

Five unclassical heteropoly blues, (H2bib)3[{TMII(H2O)2}{Sr⊂P6Mo2VMo16VIO73}]·nH2O (TM = Fe (1), Co (2), Ni (3), Cu (4), Zn (5)); bib = 1,4-bis(imidazole)butane), have been hydrothermally synthesized and fully characterized. Compounds 1–5 are based on the basket-shaped [Sr⊂P6Mo2VMo16VIO73]8− (abbreviated as {P6Mo18O73}) units, which consist of a vacant Dawson-type “basket body” {P2Mo14} unit and a “handle”-like {P4Mo4} fragment encasing a Sr2+ cation in the central cage. All the compounds exhibit isostructural 1-D zigzag chains linked by a {TM(H2O)2} unit, which are observed for the first time as 1-D basket-like assemblies connected by a TM linker. The optical band gaps of 1–5 show that they are semiconductor materials and potential photocatalysts. Compound 2 as a representative catalyst exhibits a universal highly efficient degradation ability for typical dyes MB, MO, and RhB under UV light and bifunctional electrocatalytic behavior for oxidation of AA and reduction of NO2−.

Synthesis and photo-/electro-catalytic properties of Keggin polyoxometalate inorganic–organic hybrid layers based on d10 metal and rigid benzo-diazole/-triazole ligands

Herein, five Keggin polyanion-templated inorganic–organic hybrids, (H3biz)4[SiMo12O40] (1), (H3biz)3(H2biz)[PMo12O40] (2), [{Cu7(Hbtz)2(btz)4}{PMo12O40}] (3), [{Ag7(Hbtz)2(btz)4}{AsW12O40}] (4), and [{Ag9(H2biz)2(biz)4} {H2PW12O40}] (5) (H2biz = benzimidazole, Hbtz = benzotriazole) were hydrothermally synthesized and characterized via elemental analysis, thermogravimetry (TG), infrared spectroscopy (IR), ultraviolet spectroscopy (UV), and single-crystal X-ray diffraction. A remarkable aspect of compound 1 is that six pairs of H2biz ligands are circularly arranged around the {SiMo12} cluster; this leads to the formation of a unique 2-D supramolecular layer. The most prominent feature of the structure of compound 2 is that protonated Hbiz ligands link the {PMo12} cluster into hexagonal units, which are further extended into a 2-D supramolecular array via edge-sharing modes. The Keggin {PMo12} and {AsW12} clusters in compound 3 and 4 are first extended into octa-connected 2-D sheets by the unusual heptanuclear complex {M7(Hbtz)2(btz)4} (M = Cu for 3 and Ag for 4) linker. Interestingly, two types of M–M interactions exist in the heptanuclear units. Compound 5 exhibits an unprecedented 2D network constructed from nine-nuclear silver complex {Ag9(biz)4(H3biz)2} bridges and {PW12} clusters. Most strikingly, carbene silver and the coexistence of multiple Ag–C bonds are first observed in the nine-nuclear unit. Intensive CuI/AgI–π interactions and π–π stacking play important roles in the packing arrangements of 3–5. Additionally, the electrochemical, electrocatalytic, fluorescence, and photocatalytic properties of 1–5 have been investigated in detail.

The basket-type dimer layers based on tetra-electron reduced heteropoly blue directed by copper/nickel and strontium linkers

The Sr(II) and Cu(II)/Ni(II) cations are introduced as linkers into basket POM systems, leading to two isostructural 2-D assemblies (H3bth)4[{Sr0.5(H2O)0.5(H2O)}2{Sr(H2O)4}2{Cu0.5(H2O)}2{Sr⊂P6MoV4MoVI14O73}2]·5H2O (1) and (H3bth)4[{Sr0.5(H2O)0.5(H2O)}2{Sr(H2O)3(H2O)0.5(H2O)0.25}2{Ni0.5(H2O)}2{Sr⊂P6MoV4MoVI14O73}2]·3H2O (2) (bth = 1,6-bis(triazole)hexane), which have been characterized by X-ray crystallographic analyses, FT-IR, UV-Vis, TG-DTA, XRD, XPS, BET, and elemental analyses. The compounds are based on four-electron reduced heteropoly blue {Sr⊂P6MoV4MoVI14O73}, which is made up of the tetra-vacant γ-Dawson cluster, {P2Mo14} and the handle-shaped {P4Mo4} segment encapsulated a Sr(II) ion in the central cave. The compounds exhibit isostructural 2-D dimeric layers linked by Cu(II)/Ni(II) and Sr(II) linkers, which are observed for the first time as 2-D dimeric layer assemblies based on a basket-type cluster. The compounds exhibit highly efficient catalytic ability for the degradation of typical dyes under UV irradiation and bifunctional electrocatalytic behaviors for oxidation of dopamine (DA) and reduction of NO2−.

Self-assembly, bifunctional electrocatalytic behavior, and photocatalytic property of host–guest metal-oxide-based coordination polymers

Abstract A copper complex modified Mo-oxide hybrid network stabilized by Keggin polyoxoanion, [{Cu(bpy)2}{Mo12O34(bpy)12}][PMo12O40]2 (bpy = 2,2ʹ is-bipyridine) (1) has been synthesized via self-assembly of simple starting materials. In 1, six [MoO4(bpy)] complexes connect in two different corner-sharing modes to form triangles and linear trimer units, which interconnect alternately to form zigzag chains. {Cu(bpy)2} segments connect the chains into 2-D layers, which are further joined into 3-D supramolecular networks with 1-D channels. The {PMo12PO40} as guest molecules are incorporated into the channels. Compound 1 exhibits bifunctional electrocatalytic behavior for oxidation of ascorbic acid and reduction of H2O2, as well as high-efficient degradation ability for typical dye methylene blue under UV light.

Synthesis, crystal structure and photo/electrocatalytic properties of a 1D chain based on monocobalt-substituted arsenotungstates

Abstract A chain based on the Keggin polyoxoanions, (H2bipy)2(Hbipy) [AsW11CoO39]·H2O (bipy = 4,4′-bipyridine) (1) has been hydrothermally synthesized and characterized by elemental analysis, IR, UV, TG, and single-crystal X-ray diffraction. In 1, substituted cobalt atoms share half occupancy sites with two W atoms on two asymmetric positions of opposite W3O13 trimers forming mono-substituted Keggin arsenotungstate. The Keggin clusters of two different arrays are alternately connected to generate unique wave-like chains in –A–B–A–B– ways via Co–O–W bridge. Compound 1 exhibits bifunctional electrocatalytic behavior for oxidation of ascorbic acid (AA) and reduction of hydrogen peroxide (H2O2), and good degradation ability for three typical dyes under UV light.

Long Rigid ligand induced basket-type phosphomolybdate photo-/ electro- catalytic materials

Long rigid ligand induced two basket-type inorganic–organic hybrid materials, (H4btb)2[Sr⊂P6MoV2MoVI16O73]·2H2O (1) and (H4bbtb)(H2bbtb)4[{FeIII(H2O)4Na(H2O)2}{Sr⊂P6MoV2MoVI16O73}2]·2H2O (2) (btb = 4,4-bis(1-H-1,2,4-triazol-1-yl)biphenyl, bbtb = 1,4-bis(benzotriazol-1-3-ly) benzene), have been hydrothermally synthesized and fully characterized. Compounds 1 and 2 contain 2-electron reduced basket-type polyoxoanion {Sr⊂P6MoV2MoVI16O73} (abbreviated as {P6Mo18O73}) as a basic cluster unit. In compound 1, adjacent btb molecules are parallel to each other and interconnect via π–π interactions to form two kinds of dimeric ligand units, which are further linked alternately via weak interactions to yield a unique pure organic double chain. The basket cluster grafts onto the chain in the ABAB mode via intensive hydrogen bond interactions leading to an organic–inorganic supramolecular layer along the [011] direction. Meanwhile, each basket polyoxoanion connects to two adjacent basket cages via supramolecular interactions to form a 1D supramolecular chain along the [001] direction. The 2D layer and 1D chains intersect with each other to form a 3D network with basket cages as junctions. Compound 2 is a dimeric string connected by {Na(H2O)2} and {Fe(H2O)4} units, and is the first basket dimer chain linked by a mixed metal linker. The protonated ligand bbtb connects adjacent dimeric chains to yield a 2D supramolecular layer and a 3D network via extensive supramolecular interactions. They display dual functions of electrocatalytic properties and efficient photocatalytic performance for the degradation of refractory dye Azon Phloxine (AP) under UV light.