Sandwich-type polyoxotungstate hybrids decorated by nickel-aromatic amine complexes

Two novel nickel cluster substituted polyoxometalates: syntheses, structures and their photocatalytic activities, magnetic behaviors, and proton conduction properties

A Ni₁₂-substituted POM and a Ni₆-substituted POM have been synthesized and characterized. The compounds show a moderate catalytic activity in visible-light-driven CO₂ reduction reactions, and can serve as potential proton conduction materials.

Electrochemical Reduction-Assisted In Situ Fabrication of a Graphene/Au Nanoparticles@polyoxometalate Nanohybrid Film: High-Performance Electrochemical Detection for Uric Acid

Nanohybrid films had attracted much attention owning to the enhancement of catalytic activity. However, the fabrication time took hours to days, no matter if it was the preparation of nanohybrids or the assembly process. Furthermore, the catalytic efficiency of the nanohybrid film still remained to improve. In this paper, a reduced graphene oxide (rGO)/gold nanoparticles (Au NPs)@polyoxometalate (POM) nanohybrid film was successfully fabricated by combining electrodeposition and electrochemical reduction in situ processes. The assembly process involving no organic or polymer linker molecules [except for a precursor poly(ethylenimine) (PEI) coating for indium tin oxide (ITO)] can be completed within 1 h. The reduced POM K₆[P₂W₁₈O₆₂]·19H₂O (P₂W₁₈) was employed as reducing agents and bridging molecules for rGO and Au nanoparticles and the encapsulating molecules for the Au nanoparticles. The most interesting one is the {rGO/Au@P₂W₁₈} modified electrode loading only the monolayer catalyst of Au@P₂W₁₈ and exhibiting comparable, even better electrochemical detection performance toward uric acid than other sensors with three to eight layers of the catalyst. The amperometric detection displayed a great sensitivity, lower detection limit, wide linear range, good long-time stability, superior selectivity, and reproducibility. The enhanced catalytic property may attribute to the improved conductivity of the film without organic or polymer linker molecules (except for a precursor PEI coating) and the electron transfer in the process of film fabrication.

Immobilization of carbonyl rhenium tripods on the surface of a trinickel-substituted Dawson-type polyoxotungstate

A monomeric trinickel(ii)-substituted phosphotungstate [H₉P₂W₁₅O₆₂Ni₃]⁹⁻ ion is stabilized by grafting three {Re(CO)₃} organometallic groups on the surface of a trinickel cluster for the first time. The resulting polyanions [P₂W₁₅O₅₆Ni₃(H₂O)₃(μ₃-OH)₃(Re(CO)₃)₃]⁶⁻ stacked along the a-axis to form a wavy line.

Synthesis, Structure, and Theoretical Investigations of an Alkaline Earth Vanadate Oxide Compound (Ca4V4O14): Electronic, Optical, and Chemical Bond Properties

One novel purely inorganic d0 polyoxovanadate compound Ca4V4O14 (1) was obtained and characterized structurally. The chain-like [V4O14]8– anion, built up from distorted VO5 trigonal bipyramids and VO4 tetrahedras is rarely observed. The reason for structural distortions is ascribed to the second-order Jahn-Teller effect. The band structure, the density of states, linear optical response functions, the dielectric constants of the static case ϵ(0), and refractive indexes were calculated by the density functional theory method. The nature of the V–O and Ca–O bonds, and of the electronic absorption peak are discussed in detail.