Poly[(μ-2,3-diethyl-7,8-di-methyl-quinoxaline-κ2N:N)(2,3-diethyl-7,8-di-methyl-quinoxaline-κN)-μ-nitrato-κ2O:O'-nitrato-κ2O,O'-disilver(I)]

The structure of the title compound, [C14H18N2)2Ag2](NO3)2, contains subtle differences in ligand, metal, and counter-anion coordination. One quinoxaline ligand uses one of its quinoxaline N atoms to bond to one silver cation. That silver cation is bound to a second quinoxaline which, in turn, is bound to a second silver atom; thereby using both of its quinoxaline N atoms. A nitrate group bonds with one of its O atoms to the first silver and uses the same oxygen to bond to a silver atom (related by symmetry to the second), thereby forming an extended network. The second nitrate group on the other silver bonds via two nitrate O atoms; one silver cation therefore has a coordination number of three whereas the second has a coordination number of four. One of the quinoxaline ligands has a disordered ethyl group.

Tungsten and Molybdenum Heteropolyanions with Different Central Ions—Correlation between Theory and Experiment

Density functional theory calculations were carried out to investigate the electronic structures of Keggin-typed [XMo₁₂O₄₀]ⁿ⁻ and [XW₁₂O₄₀]ⁿ⁻ anions with different heteroatoms (X = Zn²⁺, B³⁺, Al³⁺, Ga³⁺, Si⁴⁺, Ge⁴⁺, P⁵⁺, As⁵⁺, and S⁶⁺). The influence of solvent on redox properties of heteropolyanions was discussed. For [XW₁₂O₄₀]ⁿ⁻ systems two linear correlation: first, between the experimental redox potential and energies of LUMO orbital; and second, between the experimental redox potential and total energy interaction (calculated between internal tetrahedron (XO₄ⁿ⁻), and rest of Kegging anion skeleton, (W₁₂O₃₆)) were designated. Taking into account the similarity of XW₁₂O₄₀ⁿ⁻ and XMo₁₂O₄₀ⁿ⁻ systems (in geometry and electronic structure), the estimated redox potential of molybdenum heteropolyanions (with X being p block elements) in different solvent were proposed.

Polyoxometalate-based metal–organic frameworks for heterogeneous catalysis

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

Multi-functional photoelectric sensors based on a series of isopolymolybdate-based compounds for detecting different ions

Five molybdate-based compounds can be used as multi-functional photoelectric sensors. They act as electrochemical sensors for sensing NO₂⁻ and Cr(vi). Compound 3 also can be used as a fluorescent sensor for detecting Hg²⁺.

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.

A series of metal–organic loops templated by [SiMo12O40]4− and [β-Mo8O26]4− anions using double chelating ligands: amperometric sensing and selective photocatalytic properties

By changing the POM anions and TM ions, a series of compounds with multi-nuclear loops was formed.

Amperometric sensing and photocatalytic properties under sunlight irradiation of a series of Keggin–AgI compounds through tuning single and mixed ligands

In this work, we synthesized eight compounds based on Keggin anions and Ag^I ions by introducing L^a and L^b.

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.

Temperature-controlled formation of Anderson-type compounds and their conversion to [γ-Mo8O26]4−-based variants using pendent ligands

By tuning the reaction temperature, two Anderson- and two [γ-Mo8O26]4−-based compounds decorated by pendent organic ligands, [CuII 9(bpz)2(pz)2(H2O)24][H2(Cr(OH)5Mo6O19)4]·11H2O (1), [CuII(bpz)2(H2O)2(γ-H4Mo8O26)]·2H2O (2), [CuII 2(tea)2(H2O)6(HCr(OH)6Mo6O18)2]· 6H2O (3) and [AgI(bpz)(H2O)(γ-H4Mo8O26)0.5] (4) (bpz=4-butyl-1H-pyrazole, pz=1H-pyrazole, tea=2-[1,2,4]triazol-4-yl-ethylamine), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, IR spectra and elemental analyses. In compound 1, there are two kinds of tri-nuclear CuII clusters induced by bpz and pz ligands, respectively. Four Anderson-type anions are linked by these tri-nuclear clusters to form a “W”-type subunit. In compound 2, the [Cu(bpz)2(H2O)2]2+ subunits connect the γ-Mo8 anions to construct a chain. The remaining two non-coordinated N donors in [Cu(bpz)2(H2O)2]2+ further link two adjacent γ-Mo8 anions through Mo–N bonds. In compound 3, there exists a bi-nuclear CuII cluster [Cu2(tea)2(H2O)6]4+. The discrete bi-nuclear CuII clusters and the CrMo6 anions link each other through abundant hydrogen bonding interactions. In compound 4, the [Ag(bpz)(H2O)]+ subunits connect γ-Mo8 anions to build a zigzag chain. The chains are further fused by other [Ag(bpz)(H2O)]+ cations to form a grid-like layer. There still exist Mo–N bonds in 4. We also have investigated the electrochemical and photocatalytic properties of 1–4.