Electronic Consequences of Ligand Substitution at Heterometal Centers in Polyoxovanadium Clusters: Controlling the Redox Properties through Heterometal Coordination Number

The rational control of the electrochemical properties of polyoxovanadate-alkoxide clusters is dependent on understanding the influence of various synthetic modifications on the overall redox processes of these systems. In this work, the electronic consequences of ligand substitution at the heteroion in a heterometal-functionalized cluster was examined. The redox properties of [V5 O6 (OCH3 )12 FeCl] (1-[V5 FeCl]) and [V5 O6 (OCH3 )12 Fe]X (2-[V5 Fe]X; X=ClO4 , OTf) were compared in order to assess the effects of changing the coordination environment around the iron center on the electrochemical properties of the cluster. Coordination of a chloride anion to iron leads to an anodic shift in redox events. Theoretical modelling of the electronic structure of these heterometal-functionalized clusters reveals that differences in the redox profiles of 1-[V5 FeCl] and 2-[V5 Fe]X arise from changes in the number of ligands surrounding the iron center (e.g., 6-coordinate vs. 5-coordinate). Specifically, binding of the chloride to the sixth coordination site appears to change the orbital interaction between the iron and the delocalized electronic structure of the mixed-valent polyoxovanadate core. Tuning the heterometal coordination environment can therefore be used to modulate the redox properties of the whole cluster.

Solid-state-stabilization of molecular vanadium oxides for reversible electrochemical charge storage

The solid-state stabilization of a molecular vanadium oxide cluster using molecular crystal engineering is reported together with its performance in electrochemical energy storage.

Water Purification and Microplastics Removal Using Magnetic Polyoxometalate-Supported Ionic Liquid Phases (magPOM-SILPs)

Filtration is an established water‐purification technology. However, due to low flow rates, the filtration of large volumes of water is often not practical. Herein, we report an alternative purification approach in which a magnetic nanoparticle composite is used to remove organic, inorganic, microbial, and microplastics pollutants from water. The composite is based on a polyoxometalate ionic liquid (POM‐IL) adsorbed onto magnetic microporous core–shell Fe₂O₃/SiO₂ particles, giving a magnetic POM‐supported ionic liquid phase (magPOM‐SILP). Efficient, often quantitative removal of several typical surface water pollutants is reported together with facile removal of the particles using a permanent magnet. Tuning of the composite components could lead to new materials for centralized and decentralized water purification systems.

Reply to Comment on Stabilization of Low-Valent Iron(I) in a High-Valent Vanadium(V) Oxide Cluster

The authors of the Communication "Stabilization of Low-Valent Iron(I) in a High-Valent Vanadium(V) Oxide Cluster" reply to a Comment by Dr. Sproules, who offered an alternative interpretation of the metal oxidation states in the two electron reduced iron vanadate (NH₂ Me₂ )[(FeCl)V₁₂ O₃₂ Cl]^4- .

From molecular to colloidal manganese vanadium oxides for water oxidation catalysis

The spontaneous, sonication-driven conversion of a molecular manganese vanadium oxide water oxidation catalyst, (n-Bu₄N)₃[Mn₄V₄O₁₇(OAc)₃] × 3H₂O, into colloidal manganese vanadium oxide particles (average particle size ca. 70 nm) together with their stability and chemical water oxidation activity is reported. The nanoparticulate metal oxide colloid (approximate composition: VMn₅O₁₀·ca. 6H₂O·ca. 0.2nBu₄N⁺) is formed spontaneously when the molecular precursor is sonicated in water. The particles show water oxidation activity when combined with Ce^IV as the oxidant, are stable even under highly acidic reaction conditions and can be recovered and reused.