Semimetal-functionalised polyoxovanadates

The Cu(i)-catalysed Huisgen 1,3-dipolar cycloaddition route to (bio-)organic functionalisation of polyoxovanadates

We elaborated a synthetic protocol that provides convenient access to a “click”-directed covalent conjugation between ⁵¹V-NMR detectable, redox-active polyoxo(alkoxo)vanadate and (bio-)organoazides. The compounds can potentially be used in bioelectronics, biocatalysis and biosensorics.

In situ ligand exchange-mediated 0D/1D transformation of a polyoxovanadate

The antimonato-polyoxovanadate {Ni^II(en)₃}₃[VIV15SbIII6O₄₂(H₂O)]·ca.15H₂O was utilized as a synthon for the solvothermal in situ generation of the new compound {Ni^II(phen)₃}₂[{Ni^II(en)₂}VIV15SbIII6O₄₂(H₂O)]·19H₂O, a rearrangement induced by ligand metathesis.

A highly-flexible cyclic-decavanadate ligand for interconversion of dinuclear- and trinuclear-cobalt(ii) and manganese(ii) cores

The conformation of a cyclic-decavanadate ligand was reversibly transformed in response to the nuclearity of the central metal core.

Synthesis, crystal structure and spectroscopic studies of a series of hexavanadate hybrids with multiple functional groups

POV hybrids incorporated with the CC double bond can be prepared with DMAP-catalyzed esterification for the first time.

An unprecedented antimonato-polyoxovanadate (SbPOV) based on both α-[V14Sb8O42]4− and β-[V14Sb8O42]4− isomers

An unprecedented antimonato-polyoxovanadate (SbPOV) based on both α-[V₁₄Sb₈O₄₂]⁴⁻ and β-[V₁₄Sb₈O₄₂]⁴⁻ isomers has been synthesized.

β-{Cr[RC(CH2O)3]2Mo6O18}3−: the first organically-functionalized β isomer of Anderson-type polyoxometalates

The first organically-functionalized butterfly-shaped β isomer of Anderson-type polyoxometalates was discovered, which will enrich polyoxometalates chemistry.

Ligand-Directed Assembly of Polyoxovanadate-Based Metal-Organic Polyhedra

Three new polyoxovanadate-based metal-organic polyhedra (VMOPs) have been successfully synthesized and structurally characterized. Single crystals of three VMOPs were obtained by reaction of VCl3 and different carboxylate ligands (2,5-H2TDA = thiophene-2,5-dicarboxylic acid for VMOP-4, m-H2BDC = 1,3-benzenedicarboxylic acid for VMOP-5, 2,6-H2NDC = 2,6-naphthalenedicarboxylic aid for VMOP-6) under solvothermal conditions. Though all of the three hybrids feature the same {V(V)V4(IV)} units, their structures exhibit differences changing from truncated triangular prism to truncated quadrangular prism to octahedron, mainly depending on the nature of carboxylate ligands. Furthermore, the magnetic investigations reveal that VMOP-4-6 show similar ferromagnetic behaviors.

Anderson-like alkoxo-polyoxovanadate clusters serving as unprecedented second building units to construct metal-organic polyhedra

Unprecedented Anderson-like alkoxo-polyoxovanadate [V6O6(OCH3)9(μ6-SO4)(COO)3](2-) polyanions can serve as 3-connected second building units (SBUs) that assemble with dicarboxylate or tricarboxylate ligands to form a new family of metal organic tetrahedrons of V4E6 and V4F4 type (V = vertex, E = edge, and F = face). To our knowledge, this alkoxo-polyoxovanadate-based SBU is the first ever reported.

Small, beautiful and magnetically exotic: {V4W2}- and {V4W4}-type polyoxometalates

Minimal-nuclearity vanadato-tungstate clusters in [{V(IV)(dien)}4WO14]·4H2O () and [{V(IV)(dien)}4WO20]·6H2O () feature cores of edge-sharing WO6 octahedra, surrounded by a ring of four vanadyl groups. Surprisingly, the V(iv) centers in both and are ferromagnetically coupled, in contrast to all other known vanadato-polyoxotungstates featuring the ubiquituos V-O-W-O-V exchange pathways.

High Nuclearity Antimonato-Polyoxovanadate Cluster {V15 Sb6 O42 } as a Synthon for the Solvothermal in situ Generation of α- and β-{V14 Sb8 O42 } Isomers

New heteroatom polyoxovanadates (POVs) were synthesized by applying a water-soluble high-nuclearity cluster as new synthon. The [V15 Sb6 O42 ](6-) cluster shell exhibiting D3 symmetry was in situ transformed into completely different cluster shells, namely, the α-[V14 Sb8 O42 ](4-) isomer with D2d and the β-[V14 Sb8 O42 ](4-) isomer with D2h symmetry. The solvothermal reaction of {Ni(en)3 }3 [V15 Sb6 O42 (H2 O)x ]⋅15 H2 O (x=0 or 1; en=ethylenediamine) in water led to the crystallization of [{Ni(en)2 }2 V14 Sb8 O42 ]⋅5.5 H2 O containing the β-isomer. The addition of [Ni(phen)3 ](ClO4 )2 ⋅0.5 H2 O (phen=1,10-phenanthroline) to the reaction slurry gave the new compound {Ni(phen)3 }2 [V14 Sb8 O42 ]⋅phen⋅12 H2 O with the α-isomer. Both transformation reactions are complex due the change of symmetry, the chemical composition, and rearrangement of the VO5 square pyramids and Sb2 O5 handle-like moieties.

Catalysis of "outer-phase" oxygen atom exchange reactions by encapsulated "inner-phase" water in {V15Sb6}-type polyoxovanadates

A water molecule encapsulated inside water-soluble {V₁₅Sb₆} antimonato polyoxovanadate cages accelerates oxygen-exchange reactions in the cluster periphery.

Antimonato polyoxovanadate (POV) cluster compounds {M(en)₃}₃[V₁₅Sb₆O₄₂(H₂O)_x]·nH₂O (M = Fe^II, Co^II, Ni^II and x = 0 or 1) obtained under solvothermal conditions exhibit unusual high water solubility making these compounds promising synthons for generation of new POV structure types. Electrospray ionization mass spectrometry provides evidence (i) for a water molecule encapsulated inside the cavity of a fraction of the spherical cluster shells, (ii) for a post-functionalization in water, namely a slow exchange of VO against Sb₂O, (iii) for the inner-phase reactivity of the encapsulated water that is capable of opening an oxo-bridge, and (iv) for a significant acceleration of the ¹⁶O/¹⁸O exchange reactions of oxygen atoms in the cluster periphery with surrounding H₂¹⁸O, when encapsulated water is present. To the best of our knowledge, this is the first example in polyoxovanadate chemistry for the transduction of inner-phase reactivity of an encapsulated guest molecule into changes in the outer-phase reactivity of the cluster. Magnetic susceptibility measurements reflect the individual contributions of the frustrated {V₁₅} spin polytope and the {M(en)₃}²⁺ complexes, with very weak coupling between these groups.

Vanadoantimonates: from discrete clusters to high dimensional aggregates

Five new vanadoantimonates have been obtained under hydrothermal conditions and characterized.

Supramolecular 3d–4f single-molecule magnet architectures

Cooperative hydrogen bonds are key to the formation of nanosized {[{Ln^III}{H₂O⊂CrIII3LnIII6}]₂(H₂O)}-type single-molecule magnets, templated by a central water triad.

Chemoprotective activity of mixed valence polyoxovanadates against diethylsulphate in E. coli cultures: insights from solution speciation studies

Cell survival after treatment with dimethylsulphate in the presence of polyoxovanadates.

Room-temperature catalytic oxidation of alcohols with the polyoxovanadate salt Cs5(V14As8O42Cl)

Herein we present some initial results demonstrating the room temperature oxidation of secondary alcohols catalyzed by the reduced salt-inclusion polyoxometalate, Cs₅(V₁₄As₈O₄₂Cl).

New organic–inorganic hybrid compounds constructed from polyoxometalates and transition metal mixed-organic-ligand complexes

Five compounds constructed from different polyoxoanions and metal mixed-organic complexes of carboxylates and nitrogen-containing ligands have been synthesized and characterized.

A Layered Manganese(IV)-Containing Heteropolyvanadate with a 1:14 Stoichiometry

A novel manganese(IV)-containing symmetrical heteropolyvanadate was prepared by the transformation of K7[MnV13O38]·18H2O (K7MnV13) to K4Li2[MnV14O40]·21H2O (1) at pH 4. The heteropolyanion [MnV14O40](6-) (MnV14) is composed of a MnO6 octahedron surrounded by 14 edge-sharing VO6 octahedra. The simplified representation of MnV14 has a new topology termed jba1 with a total point symbol of {3(10)}2{3(14).4(7)}4{3(18).4(10)}8{3(44).4(46).5}. In the crystal lattice of 1, MnV14 packs with potassium ions, forming a 2D layered K2[MnV14O40](4-) network (ABABAB...). Four K(+) ions cap the four square O4 faces of MnV14, apparently stabilizing the heteropolyanion. Compound 1 catalyzes the t-BuOOH-based oxidation of 2-chloroethyl ethyl sulfide (a mustard gas simulant). The magnetic and catalytic properties of 1 are discussed.