A Keggin-type polyoxomolybdate-based crystalline material formed by hydrothermal transformation: photo/electro-catalytic properties and mechanism study

This study constructs a POM-based crystalline material of [(SiMo12O40)Cu6(2,2′-bipy)6(Mo6O22)] (1). The photocatalytic MB degradation and electrocatalytic nitrite reduction properties of complex 1 are systematically studied for the first time.

Polyoxometalate-based metal–organic frameworks for heterogeneous catalysis

POM-based MOFs simultaneously possessing the virtues of POMs and MOFs exhibit excellent heterogeneous catalytic properties.

A series of Keggin- and Wells-Dawson-polyoxometalate-based compounds constructed from oxygen-functional imidazole derivatives

Through the use of two kinds of imidazole derivatives containing different O-functional units, three new Keggin- and one Wells-Dawson-polyoxometalate (POM)-based compounds, namely [Cu2La4(HPW12O40)] (1), [CuLa4(H2O)2(HPMo12O40)] (2), [Cu2La7(H2O)(H2P2W18O62)]·La(3), [Ag2(Lb4)(HPMo12O40)]·Lb·H2O (4)(La= (4-(2,5-dihydro-1H-imidazol-1-yl)benzaldehyde), and Lb=(4-(2,5-dihydro-1H-imidazol-1-yl)benzoic acid), were synthesized and characterized using single-crystal X-ray diffraction, elemental analyses, and infrared spectroscopy. The polyoxoanions occupy holes framed by two symmetrically oriented CuLa2 units in 1. In compound 2, the square-planar CuLa4 units form a two-dimensional (2D), supramolecular grid through π···π stacking interactions. The POMs occupy vacancies in this grid. In compound 3, the CuLa3 subunits connect the neighboring P2W18 units and an “S”-type chain is formed. Through hydrogen bonding interactions, the chains are connected to form a layer. In compound 4, the POM anions are linked by AgLb2 subunits to form a chain. All the chains are tied together to construct a layer structure with weak hydrogen bonding interactions between the terminal carboxylic acid functional groups of ligands Lb. The electrocatalytic and photocatalytic activities of all these four compounds were also studied.

Effective photocatalytic and bifunctional electrocatalytic materials based on Keggin arsenomolybdates and different transition metal capped assemblies

V, Co, and Cu were introduced into {AsMo₁₂} system to build three Keggin derivatives with different caps, which show excellent photocatalytic activity and bifunctional electrocatalytic behavior.

A series of organic–inorganic hybrid compounds formed by [P2W18O62]6−and several types of transition metal complexes

A series of new organic–inorganic hybrid compounds based on [P₂W₁₈O₆₂]⁶⁻and several types of transition metal complexes have been synthesized and characterized.

Crystal structure of octa-kis-(N,N-di-methyl-formamide-κO)europium(III) tetra-cosa-μ2-oxido-dodeca-oxido-μ12-phosphato-dodeca-molybdate(VI)

In the title salt, [Eu(C3H7NO)8][PMo12O40], the asymmetric unit comprises one α-Keggin-type [PMo12O40](3-) polyoxidometalate anion and one distorted dodeca-hedral [Eu(C3H7NO)8](3+) complex cation. In the crystal, the isolated polyoxidometalate anions are packed into hexa-gonally arranged rows extending parallel to [001]. The complex cations are situated between the rows and are linked to the neighbouring anions through weak C-H⋯O hydrogen-bonding inter-actions, leading to the formation of a three-dimensional network structure.

Architectural chemistry of polyoxometalate-based coordination frameworks constructed from flexible N-donor ligands

Polyoxometalate-based coordination frameworks (POMCFs) constructed from flexible N-donor ligands can exhibit diverse properties and fascinating architectures, extending the families of material chemistry and structural chemistry.

An unprecedented 3D POM–MOF based on (7,8)-connected twin Wells–Dawson clusters: synthesis, structure, electrocatalytic and photocatalytic properties

The first (7,8)-connected POM–MOF has been obtained, representing the highest connected POMs to any mixed-connected POM–MOF and a unique structure that contains organic–inorganic and all-inorganic networks.

Two novel topological structures of [Cu(CN)] coordination polymers modified by flexible triazole ligands

Triazole ligands have been introduced into the {Cu(CN)} skeleton to produce appealing polymers, which exhibit certain thermal stability and fluorescence properties.

Temperature-induced racemic compounds and chiral conglomerates based on polyoxometalates and lanthanides: syntheses, structures and catalytic properties

Four new species, originated from [Co₂Mo₁₀H₄O₃₈]⁶⁻ and lanthanides by adjusting the reaction temperature, are reported, which act as Lewis acid–base catalysts toward the cyanosilylation reaction.

Organic–inorganic hybrid assemblies based on Ti-substituted polyoxometalates for photocatalytic dye degradation

New organic–inorganic hybrid compounds based on Ti-substituted polyoxometalates exhibit high photocatalytic dye (MB) degradation activities.

Construction of POMOFs with different degrees of interpenetration and the same topology

Three POMOFs with different degrees of interpenetration are reported and the influence of the organic molecules on the degree of interpenetration of the compounds is discussed.

An ultrastable, flexible POM-based coordination polymer with redox properties

A new porous coordination polymer (1) has been prepared under hydrothermal conditions. The flexible framework of1shows dynamic behavior accompanied with the removal/adsorption of guest water molecules. Remarkably, crystals of1can remain intact even in 8 mol L⁻¹hydrochloric acid, dilute NaOH solution (pH = 12) and boiling water.

A new 3D framework based on reduced Wells-Dawson arsenotungstates as eight-connected linkages

A compound representing the first example of high dimensional and high connected hybrid based on reduced Wells-Dawson arsenotungstates has been synthesized, and its electrocatalytic and photocatalytic properties have been investigated.

Assembly and photocatalysis of two novel 3D Anderson-type polyoxometalate-based metal–organic frameworks constructed from isomeric bis(pyridylformyl)piperazine ligands

Two 3D Anderson-based MOFs constructed from two isomeric bis(pyridylformyl)piperazine have been synthesized. The isomeric ligands and Anderson-type polyanions play key roles in the construction of the final frameworks.

Synthesis of a poly-pendant 1-D chain based on ‘trans-vanadium’ bicapped, Keggin-type vanadtungstate and its photocatalytic properties

A vanadtungstate cluster-based organic–inorganic hybrid material [NiL₄V^IVW^VI₁₀W^V₂O₄₀(V^IVO)₂] was synthesized, which not only serves as an active photocatalyst for the degradation of dye molecules, but also exhibits selective photocatalytic degradation of cationic dyes in aqueous solution.

pH-controlled assembly of hybrid architectures based on Anderson-type polyoxometalates and silver coordination units

Three new architectures based on Anderson-type polyoxometalates, (3-H2pya)[(3-Hpya)2Ag][AgAlMo6H6O24]·3H2O 1, HNa2[(3-pya)(3-Hpya)Ag]2[AlMo6H6O24]·8H2O 2 and [(3-Hpya)2Ag][(H2O)2Ag]2[AlMo6H6O24]·2H2O 3 (3-Hpya = 3-(3-pyridyl)acrylic acid), have been synthesized at the different pH values and characterized by elemental analysis, IR spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compound 1 was obtained at lower pH value (2.50), and represents a 3D host-guest compound containing the Ag-3-Hpya coordination complex guest and the 3D [AgAlMo6H6O24](2-) host. The host framework exhibits a 4-connected diamond topology, and is constructed from [AlMo6H6O24](3-) clusters connected by Ag(+) cations. When the pH value was increased slightly, compound 2 was obtained with a 1D chain structure built up of Anderson polyoxoanions, Ag-3-Hpya coordination complexes and binuclear sodium clusters. By further increasing the pH value (3.50), compound 3 was isolated as a 2D network in which [AlMo6H6O24](3-) clusters are linked together by Ag(+) cations and Ag-3-Hpya coordination complexes. Their structural differences reveal that the pH value of the reaction system is the key factor influencing the structure and topology of three compounds. The UV-visible-NIR diffuse reflectivity spectra of 1-3 show that they can be regarded as a wide gap semiconductor. Furthermore, the pyrolysis of 1-3 produces three nanocomposites 1'-3' composed of silver microparticles dispersed in the metal oxides. The photocatalytic properties of 1'-3' have been investigated.