• Title/Summary/Keyword: Oxovanadium (IV)

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Synthesis and Characterization of Metal Complex Oxo Vanadium(Ⅳ) Complexes with Derivatives of Salicylaldoximes (옥심계 금속착물의 합성과 그 물성에 관한 연구 치환 살리실알데히드옥심의 바나듐(Ⅳ) 착물(1))

  • Lee, Kwang;Lee, Won Sik
    • Journal of the Korean Chemical Society
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    • v.39 no.8
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    • pp.611-616
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    • 1995
  • Oxovanadium(IV) complexes with salicylaldoxime, o-vanilline oxime, 2-hydroxy-4-methoxybenzaldoxime, 2-hydroxy-5-methoxybenzaldoxime and 2-hydroxy-5-nitrobenzaldoxime were synthesized. The complexes have been characterized by elemental analysis, electric conductivity measurement, infrared spectrometry, electronic spectrometry, mass spectrometry, and thermal analysis. The results of elemental analysis were well coincided with the theoretical values. The values of molar conductance of the complexes in DMF implicated that the complexes were non-electrolyte. The characteristic stretching frequency of V=O appeared strong band in the range of $980{\pm}20\;cm^{-1}.$ All the complexes showed two d-d transition in visible spectra and two charge transfer transitions in ultraviolet spectra. Results of mass spectrometry of $VO(sal)_2\;and\;VO(van)_2$ indicated two peaks corresponding to vanadium containing ion(I) of 1 : 2(metal to ligand) chelate and a fragment ion(II) of 1 : 1 chelate due to loss of ligand radical from ion(I). The thermal analysis showed the endothermic peak due to the thermal decomposition.

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EPR Study of${\gamma}(1,2)-[H{_n}SiV^{IV}VW_{10}O_{40}]^{(7-n)-}$ (n = 0, 1 or 2). Identification of Four One-Electron Reduction Products and Evidence for Proton Transfer in the Solid State

  • Jeongmin Park;Hyunsoo So
    • Bulletin of the Korean Chemical Society
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    • v.15 no.9
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    • pp.752-758
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    • 1994
  • Several one-electron reduction products of ${\gamma}$(1,2)-[$H_nSiV_2W_{10}O_{40}]^{(6-n)-}$ were separated by precipitating or coprecipitating with diamagnetic host compounds at different pH. Mono-and diprotonated species, 1 and 2, in powder samples exhibit aPR spectra characteristic of a mononuclear oxovanadium species, indicating that the unpaired electron is trapped at one vanadium atom. The EPR spectrum of the unprotonated species 0 shows 15 parallel lines, indicating that the unpaired electron interacts equally with two vanadium atoms. While different species were precipitated depending upon the pH of the solution and the charge of the host anion, only one species 1' was formed in the frozen solutions at pH 3.2-4.7. The EPR spectrum of 1' indicates that the unpaired electron is trapped at one vanadium atom and 1/16 of the spin density is delocalized onto the second vanadium atom. The species 1' is probably another form of the monoprotonated species. The EPR spectra show that some of 2 transform into 1 and some of 0 transform into 1' in the solid state at low temperatures. It is suggested that proton transfer between the heteropolyanion and water molecues in the solid state is involved in these transformations.