Stepwise Synthesis of Disk- and Ball-Shaped Polyoxovanadates: All-Inorganic Coordination Chemistry of Polyoxovanadates

Hayashi, Yoshihito; Shinguchi, Takayuki; Kurata, Taisei; Isobe, Kiyoshi

doi:10.1021/bk-2007-0974.ch029

Cited by 7 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The charge balance and structural stabilities with the template determine the size of the condensed polyoxometalates. To adjust the stoichiometry of the reaction and achieve the optimum yield, the addition of an optimized amount of acid is required to promote the dehydration condensation reaction [35]. The protonated form of the tetravanadate has a bending tetranuclear structure in a butterfly form.…”

Section: General Methods For the Synthesis Of Polyoxovanadatesmentioning

confidence: 99%

Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects

Hayashi

2011

Coordination Chemistry Reviews

Self Cite

213

126

View full text Add to dashboard Cite

Many synthetic methods for heteropolyoxovanadates and lacunary polyoxovanadates have been developed in recent years. We outline various approaches used to produce new polyoxovanadate species, including heterometal-incorporated complexes of tetravanadates, hexavanadates, decavanadates and dodecavanadates. In particular, three types of synthetic routes are explored; based on i) coordination of metavanadate species to transition metal cations, ii) oxidation of reduced polyoxovanadates, and iii) template synthesis. Metavanadate species can coordinate to metal cations as inorganic macrocyclic ligands to form heteropolyoxovanadates. The incorporation of a heterometal cation into decavanadates has also been reported. The oxidation reaction of reduced polyoxovanadates provides a new route to the formation of the lacunary polyoxovanadates, which can serve as inorganic host molecules. Dodecavanadates are bowl-type molecules of particular structural interest; a chloride anion can be incorporated into the bowl through a template synthesis. Structural transformations between these dodecavanadate species and alkoxopolyoxovanadates are also described.

show abstract

Section: General Methods For the Synthesis Of Polyoxovanadatesmentioning

confidence: 99%

Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects

Hayashi

2011

Coordination Chemistry Reviews

Self Cite

213

126

View full text Add to dashboard Cite

show abstract

“…Partial reduction and re-condensation provide polyoxidovanadates which are stable even in strongly acidic media. 85 An example is the hexadecavanadate that contains the anion [Br ⊂ V V 9 V IV 7 O 38 ] 4− , 86 with the bromide located in the interior of the cage-like structure (Fig. 11b).…”

Section: The Potentiality Of Vanadates and Vanadium Oxidesmentioning

confidence: 99%

The future of/for vanadium

2013

View full text Add to dashboard Cite

Vanadium compounds are stored or employed by several groups of bacterial and eukaryotic organisms. Two types of vanadium-dependent enzymes have so far been characterised: vanadate-dependent haloperoxidases from fungi, lichens, marine macroalgae and Streptomyces bacteria, and vanadium nitrogenases in proteo- and cyanobacteria. Several bacterial strains can employ vanadate(V) as an external electron acceptor in respiration, reducing vanadate to VO(2+) and thus contributing to the mineralisation of vanadium and to the detoxification of vanadate-contaminated water. Amanita mushrooms and many sea squirts accumulate vanadium, without the importance of this practise being well understood. Further, the analogy between vanadate and phosphate implicates an interference of vanadate with metabolic processes involving phosphate, suggesting a regulatory role for vanadate in most if not all organisms, including humans, but also hinting at toxic effects at unphysiologically high vanadate concentrations. The antidiabetic effect of vanadium compounds is probably related to the phosphate-vanadate antagonism, as is the potentiality of vanadate in the amelioration of cardiovascular affliction. The anti-cancer action of vanadium compounds and their in vitro activity towards the protozoa causing amoebiasis, leishmaniasis and Chagas' disease again may be rooted in the intervention of vanadate with the activity of phosphatases and kinases. In addition, most likely the ability of vanadate(V) and oxidovanadium(IV) to regulate the cellular production of reactive oxygen species comes in, thus influencing cellular signalling. Future developments of vanadium chemistry are likely to emphasize topics related to biological, environmental and medicinal aspects. Condensation of monovanadate results in the formation of oligovanadates, polyvanadates and finally colloidal and solid vanadium oxides that, in part, convey bio-mimetic functions comparable to those of simple vanadate, including its catalytic potential as an active centre in haloperoxidases and the lethal action against viruses, bacteria and protozoan parasites. Decavanadate has been shown to be stabilised by docking to proteins, and by integration into nanoscopic water pools of intracellular compartments, modelled by reverse micelles. The well established and approved use of vanadium oxides in, amongst other applications, catalysis has been recently impacted by the elucidation of the active surface species--VO(x)--of catalysts based on mixed vanadium oxides, and vanadium oxides on supports. Finally, materials based on vanadium oxides and vanadates play an increasingly important role as cathode materials in high density lithium batteries. An example is Ag2VO2PO4, which, in the discharge process, is reduced to Li(3.2)VO2PO4 and Ag. Oncoming developments in vanadium chemistry thus include oxide-based materials.

show abstract

“…We employed relatively mild reducing condition for the synthesis of 1 through the reductive coupling scheme. 20 Instead of typical reducing reagents, we employed a more mild reduction of the polyoxovanadate by utilizing a catalytic oxidation reaction of olefin by a palladium complex. The catalytic oxidation of COD (1,5-cyclooctadiene) by [Pd(COD)Cl 2 ] with [V 10 O 26 ] 4− is possible, contrary to the polyoxovanadates that have to be reduced in an inert atmosphere.…”

Section: Synthetic Strategymentioning

confidence: 99%

Discrete spherical hexadecavanadates incorporating a bromide with oxidative bromination activity

Kato

Hayashi

2013

Dalton Trans.

Self Cite

View full text Add to dashboard Cite

Two discrete hexadecavanadates, (n-Bu4N)4[V16O38(X)] (X = Cl(-) (1) and X = Br(-) (2)), were synthesized by a reaction of [V10O26](4-) with a template anion resulting in the incorporation of chloride or bromide in the {V16} spherical cluster framework. The reaction of [V10O26](4-) with p-toluenesulfonic acid proceeded under an aerobic environment to give 2 in the presence of an excess amount of bromide anion, which acted as both a template anion and a reducing reagent for the formation of the mixed-valence framework. For the synthesis of cluster 1, additional reductive conditions were required due to the weak reducing ability of the chloride anion. The crystal structures of 1 and 2 were determined using single-crystal X-ray diffraction analysis. Both were found to consist of a discrete [V(V)9V(IV)7O38(X)](4-) framework by the linkage of VO5 pyramidal units. Cyclic voltammetric studies of 1 and 2 in acetonitrile showed a series of stepwise reversible redox processes, which were due to the redox of the spherical polyoxovanadate frameworks. The oxidative bromination reactions of aromatic substrates were also investigated using cluster 2 as a catalyst under aerobic conditions.

show abstract

Stepwise Synthesis of Disk- and Ball-Shaped Polyoxovanadates: All-Inorganic Coordination Chemistry of Polyoxovanadates

Cited by 7 publications

References 0 publications

Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects

Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects

The future of/for vanadium

Discrete spherical hexadecavanadates incorporating a bromide with oxidative bromination activity

Contact Info

Product

Resources

About