Vanadyl Acetate Research Articles

Al3+ ion storage behaviour in organic-inorganic vanadyl acetate with aqueous and gel electrolytes

Al3+ ion storage behaviour in organic-inorganic vanadyl acetate with aqueous and gel electrolytes

Emergence of fractional quantum mechanics in condensed matter physics

Condensed matter provides a fertile ground for the emergence of exotic phenomena. For instance, polymers typically lack long range order and crystalline symmetry, leading to difficulties in establishing a general theory to describe the properties of these materials. They exhibit memory, some extent of self-similarity and non-locality effects, which are better described by fractional calculus. In this letter we demonstrate the emergence of an effective Hamiltonian possessing fractional dispersion taking as the starting point a tight-binding model in which the hopping parameters from next-nearest neighbours cannot be neglected. Our model was applied to describe the Pauli paramagnetism in a system with fractional dispersion, the magnetic susceptibility of vanadyl acetate and the electronic transport as a function of temperature in conductive polymers, displaying good agreement between theory and experimental data.

Facile synthesis of one-dimensional vanadyl acetate nanobelts toward a novel anode for lithium storage.

Transition metal oxides (TMOs) are prospective anode materials for lithium-ion batteries (LIBs), owing to their high theoretical specific capacity. However, the inherently low conductivity of TMOs restricts their application. The coupling of lithium-ion conducting polymer ligands with TMO structures is favorable for the dynamics of electrochemical processes. Herein, vanadyl acetate (VA) nanobelts, an organic-inorganic hybrid material, are synthesized for the first time as an anode material for LIBs. As a result, the VA nanobelt electrode displays an outstanding electrochemical performance, including a highly stable reversible specific capacity (around 1065 mA h g-1 at 200 mA g-1), superior long-term cyclability (with a capacity of approximately 477 mA h g-1 at 2 A g-1 over 500 cycles) and attractive rate capability (1012 mA h g-1 when the current density recovers to 200 mA g-1). In addition, scanning electron microscopy (SEM), cyclic voltammetry (CV) curves at different scanning rates and electrochemical impedance spectroscopy (EIS) are used to investigate the variation of the specific capacity and the electrochemical kinetic characteristics of the VA electrode during cycling in detail, respectively. Also, the structural variations of the VA electrode in the initial two cycles are also investigated by in situ XRD testing. The periodic evolution of the in situ XRD patterns demonstrates that the VA nanobelt electrode shows excellent reversibility for Li+ ion insertion/extraction. This work offers an enlightening insight into the future research into organo-vanadyl hybrids as advanced anode materials.

One step electrodeposition of V2O5/polypyrrole/graphene oxide ternary nanocomposite for preparation of a high performance supercapacitor

A new ternary nanocomposite based on graphene oxide (GO), polypyrrole (PPy) and vanadium pentoxide (V2O5) is obtained via one-step electrochemical deposition process. Electrochemical deposition of V2O5, PPy and GO on a stainless steel (SS) substrate is conducted from an aqueous solution containing vanadyl acetate, pyrrole and GO to get V2O5/PPy/GO nanocomposite. Characterization of the electrode material is carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). The electrochemical performance of the as-prepared nanocomposite is evaluated by different electrochemical methods including cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) in 0.5 M Na2SO4 solution. Remarkably, V2O5/PPy/GO nanocomposite shows a specific capacitance of 750 F g−1 at a current density of 5 A g−1, which is far better than PPy (59.5 F g−1), V2O5/PPy (81.5 F g−1) and PPy/GO (344.5 F g−1). Furthermore, V2O5/PPy/GO maintains 83% of its initial value after 3000 cycles, which demonstrates good electrochemical stability of the electrode during repeated cycling. These results demonstrate that the combination of electrical double layer capacitance of GO and pseudocapacitive behavior of the PPy and V2O5 can effectively increase the specific capacitance and cycling stability of the prepared electrode. Also, a symmetric supercapacitor device assembled by V2O5/PPy/GO nanocomposite yielded a maximum energy density of 27.6 W h kg−1 at a power density of 3600 W kg−1, and a maximum power density of 13680 W kg−1 at an energy density of 22.8 W h kg−1.

Solvothermal synthesis of nanosized particles of vanadium oxide

The interaction of vanadyl acetate, vanadium(V) oxide, and vanadium(V) isopropylate with capronic acid has afforded a series of nanosized vanadium oxide powders. The products structure has been studied by X-ray diffraction analysis. Both amorphous and crystalline powders of vanadium oxide can be prepared depending on the starting compound, temperature, and the synthesis duration, the V2O3 (karelianite) structure being in all the cases the most thermodynamically stable. Photocatalytic properties of the prepared powders have been studied.

Kinetics and mechanism of vanadium(IV) oxidation by tetrabutylammonium tribromide

The reaction between tetrabutylammonium tribromide(TBATB) and vanadium(IV) has been studied in 50% (v/v) acetic acid under second order conditions. The overall order of reaction is found to be two, unity in each reactant. The reaction involves two single-electron transfer steps generating bromine free radical in the first rate determining step. The test for the formation of free radicals in presence of added acrylonitrile was negative while added toluene increases the rate of the reaction considerably due to its conversion into benzyl bromide. The reaction is retarded by hydrogen ions as a result of protonation prior equilibria of the active reductant, vanadyl acetate. The oxidation of the vanadylsalen complex by TBATB proceeds more rapidly than that of vanadyl acetate but follows the similar kinetic behaviour. Considerable decrease in the entropy of activation of the reaction indicates formation of an ordered transition state between the two reactants and since the kinetic behaviour remains unaltered, even after the change in the ligand attached to the reductant, indicates an interaction between the reactants through the oxygen atom on the vanadyl ion.

The first enantioselective synthesis of the amavadin ligand and its complexation to vanadium

The ligand of the naturally occurring vanadium compound amavadin found in Amanita muscaria, (2 S, 2′ S)- N-hydroxyimino-2,2′-dipropionic acid ( 1), was synthesized stereoselectively in two steps with 43% overall yield. After complexation of this ligand to vanadyl acetate, amavadin was isolated in quantitative yield. Due to the chirality at vanadium amavadin consists of a mixture of Δ and Λ diastereoisomers. Directly after its synthesis, the Δ to Λ ratio of amavadin is 2.27 and it decreases to 0.80 after equilibrium has been reached. During this epimerization the optical rotation for V[(2 S,2′ S)- N-hydroxyimino-(2,2′)-dipropionate] 2 (=amavadin) changes from [ α ] D 25 = + 36 ° to + 114.0 ° ( c = 0.5, H 2O). For V[(2 R,2′ R)- N-hydroxyimino-(2,2′)-dipropionate] the optical rotation changes from [ α ] D 25 = - 36 ° to - 113.2 ° ( c = 0.5, H 2O).

The one dimensional chain structures of vanadyl glycolate and vanadyl acetateElectronic supplementary information (ESI) available: difference plots and reflections lists for VO(CH3COO)2 and VO(OCH2CH2O). See http://www.rsc.org/suppdata/jm/b2/b208100h/

The solvothermal reaction, at 200 °C, of vanadium pentoxide and lithium hydroxide in acetic acid or ethylene glycol leads to the formation of vanadyl acetate and vanadyl glycolate respectively. The structure of the acetate contains vanadium in octahedral coordination whereas the glycolate contains VO5 square pyramids. The VO6 octahedra in the acetate, VO(CH3COO)2, are joined through the vanadyl groups, giving a rather long VO bond of 1.684(7) Å and a short trans V-O bond of 2.131(7) Å, and by bridging acetate groups. The vanadium atoms interact along the ⋯VO⋯VO⋯ chain giving one-dimensional antiferromagnetic behavior. In contrast in the glycolate, the apical VO bond is shorter, 1.58(1) Å, and the square pyramids share edges in a two up–two down fashion to give chains of formula VO(OCH2CH2O). Magnetic susceptibility of vanadyl glycolate is consistent with an isolated spin dimers model.

Vanadium-Catalysed Oxidative Ring Cleavage of Cyclic Acetals. A Facile Synthesis of Glycol Monoesters

An efficient method for the synthesis of glycol monoesters from cyclic acetals using vanadyl acetate in conjunction with tert-butyl hydroperoxide is described for the first time.

H-OXO HETEROBINUCLEAR COMPLEXES OBTAINED BY DONOR ACCEPTOR REACTIONS WITH THE VANADYL GROUP

Abstract The vanadyl complex (C22H22N4)VO, prepared by the reaction of the macrocyclic ligand, C22H24N4, with vanadyl acetate, forms adducts with Lewis acids such as triphenylboron and trimethyl silicon. All three complexes have been characterized by EPR spectroscopy and X-ray crystallographic techniques to examine the effect of adduct formation on the V=O bonding. VO(C22H22N4) is triclinic, Pl, with a = 11.150(2), b = 12.514(3), c = 8.468(2) Å, α = 101.80(2), β =105.09(3), σ = 76.27(2)°, d(obs) = 1.37 gcm–3, d(calc) = 1.381 g/cm3. (C22H22N4)V=O B(C6H5)3 is monoclinic P21/n, with a = 11.174(3), b = 20.208(4), c = 14.460(8) Å, β = 97.23(1)°, d(obs) = 1.34 gcm−3 for Z = 4. [C22H22N4)V–O–Si(CH3)3]B(C6H5)4 is monoclinic, P21/m, with a= 9.884(1), b = 13.669(4), c= 16.161(3) Å, β = 105.01(1)°, d(obs) = 1.28 gcm–3, d(calc) = 1.263 gcm–3 for Z = 4. The V=O bond distance, 1.601(2) Å, is typical of other vanadyl complexes; adduct formation with B(C6H5)3 leads only to a modest lengthening to 1.665(3) Å and weak B–O interaction is indicated by the rather long B–O distance of 1.571(6) Å. Interaction of the V=O bond with Si(CH3)3 to form a V-O-Si linkage leads to a substantial lengthening of the V-O distance, 1.751(3) Å, and a Si–O distance, 1.662(3) Å, only slightly longer than the corresponding Si–O ether oxygen distance, 1.631(3) Å. The structural and ESR parameters of these complexes are compared with related vanadyl complexes.

ChemInform Abstract: The Electrochemistry of Amavadine, a Vanadium Natural Product.

AbstractThe title compound (I), a product of the mushroom Amanita muscaria, is synthesized by the reaction of vanadyl acetate in methanol with the N‐hydroxy‐α,α‐iminodipropionic acid at the pH approximately 2. The overall yield including the known synthesis of the ligand is about 10%.