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Margarita Kantcheva - One of the best experts on this subject based on the ideXlab platform.
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Spectroscopic characterization of VOx/ZrO2 catalysts prepared using Vanadium(V) oxo complexes
Solid State Ionics, 2001Co-Authors: Margarita KantchevaAbstract:A method for deposition of Vanadium(V) oxo species on zirconia using different Vanadium(V) precursor ions is described. The samples are synthesized by suspension of the support (powder) in solutions containing: (i) the dioxoVanadium(V) ion, VO2+; (ii) the yellow diperoxo anion, [VO(OO)2]− and (iii) the red monoperoxo cation, [VO(OO)]+. The application of Vanadium(V) peroxo complexes significantly increases the uptake of Vanadium by zirconia. The state and localization of the VOx species on the surface of zirconia haVe been studied by FTIR, UV–Vis and XP spectroscopies.
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Spectroscopic characterization of VO /ZrO2 catalysts prepared using Vanadium(V) oxo complexes
Solid State Ionics, 2001Co-Authors: Margarita KantchevaAbstract:A method for deposition of Vanadium(V) oxo species on zirconia using different Vanadium(V) precursor ions is described. The samples are synthesized by suspension of the support (powder) in solutions containing: (i) the dioxoVanadium(V) ion, VO2+; (ii) the yellow diperoxo anion, [VO(O-O)2]- and (iii) the red monoperoxo cation, [VO(O-O)]+. The application of Vanadium(V) peroxo complexes significantly increases the uptake of Vanadium by zirconia. The state and localization of the VOx species on the surface of zirconia haVe been studied by FTIR, UV-Vis and XP spectroscopies. © 2001 ElseVier Science B.V
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Spectroscopic characterization of Vanadium(V) oxo species deposited on zirconia
Physical Chemistry Chemical Physics, 2000Co-Authors: Margarita KantchevaAbstract:A method for deposition of Vanadium(V) oxo species from acidic solutions of ammonium metaVanadate on zirconia is described. The samples are synthesized by suspension of the support (powder) in solutions containing three different Vanadium(V) precursor ions: the dioxoVanadium(V) ion, VO2+, the yellow diperoxo anion [VO(O–O)2]− and the red monoperoxo cation [VO(O–O)]+. Application of Vanadium(V) peroxo complexes increases significantly the uptake of Vanadium by zirconia. The state and localization of the VOx species on the surface of zirconia were studied by FTIR, UV/VIS and XP spectroscopies. The materials prepared from VO2+ ions contain isolated VO4 groups and domains of orthoVanadate species, (VO4)n. The FTIR spectra of adsorbed CO reVealed that the number of exposed Zr4+ ions decreased markedly when Vanadium(V) peroxo ions were used as precursors. The predominant surface structure in this case was identified as pyroVanadates, V2O7. On all of the samples studied no separate phase of V2O5 was detected.
Toshikazu Hirao - One of the best experts on this subject based on the ideXlab platform.
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Structural Characterization of (Arylimido)Vanadium(V) Compounds with 2,6-Difluorophenoxide Ligand
Zeitschrift für anorganische und allgemeine Chemie, 2017Co-Authors: Toshiyuki Moriuchi, Takashi Sakuramoto, Masafumi Nishina, Ryota Kawai, Toshikazu HiraoAbstract:The (arylimido)Vanadium(V) compound, [(p-MeOC6H4N)V(OiPr)3] was demonstrated to undergo ligand exchange reaction with one or two equiValents of 2,6-difluorophenol, affording the (arylimido)Vanadium(V) compounds, [(p-MeOC6H4N)V(OiPr)2(O-2,6-F2Ph)] and [(p-MeOC6H4N)V(OiPr)(O-2,6-F2Ph)2]. Their X-ray crystallographic analyses elucidated the μ-isopropoxido-bridged dimeric structures, wherein each Vanadium atom has a trigonal-bipyramidal arrangement with the imido and bridging isopropoxide ligands in the apical positions. The isopropoxide ligand was selectiVely employed as a bridging ligand between two central Vanadium atoms. On the other hand, the reaction of the (arylimido)Vanadium(V) compound, [(p-MeOC6H4N)VCl3] and three equiValents of lithium 2,6-difluorophenoxide gaVe the (arylimido)Vanadium(V) compound, [(p-MeOC6H4N)V(O-2,6-F2Ph)3]. In the crystal packing, the thus-obtained compound showed a distorted trigonal-bipyramidal enVironment at the Vanadium atoms with the μ-phenoxido-bridged dimeric structure, wherein the 2,6-difluorophenoxide ligand was found to serVe as a bridging ligand.
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Structural Characterization of (Diphenylhydrazido)Vanadium(V) Compounds
ChemistrySelect, 2017Co-Authors: Takashi Sakuramoto, Toshikazu Hirao, Toshiyuki MoriuchiAbstract:(Diphenylhydrazido)Vanadium(V) triisopropoxide was synthesized by the reaction of VO(OiPr)3 with N,N-diphenylhydrazine. The μ-isopropoxido-bridged dimeric structure was obserVed in the molecular structure of (diphenylhydrazido)Vanadium(V) triisopropoxide. The near-linear V(1)-N(1)-N(2) angle of 173.7(3)° with the V(1)-N(1) distance of 1.667(4) A indicates that the imido nitrogen has large participation of an sp-hybridized character. The phenyl substituents of the hydrazido moiety were found to conjugate with the N−N bond. Furthermore, CH-π intermolecular interaction between two benzene rings was obserVed to induce polymeric structure in a solid state. (Diphenylhydrazido)Vanadium(V) nitrilotriethoxide was obtained by the treatment of (diphenylhydrazido)Vanadium(V) triisopropoxide with 2,2′,2′′-nitrilotriethanol. The slightly increased imido angle (V(1)-N(1)-N(2), 176.4(5)°) was obserVed as compared with (diphenylhydrazido)Vanadium(V) triisopropoxide probably because of the apical coordination of the nitrogen.
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Structural Characterization of Chiral Vanadium(V) Compounds with V=N Bond
Chemistry Letters, 2017Co-Authors: Takashi Sakuramoto, Toshikazu Hirao, Toshiyuki MoriuchiAbstract:(R)-(+)-1-Phenylethoxide ligands were introduced into (4-methoxyphenylimido)Vanadium(V) or (dimethylhydrazido)Vanadium(V) compound to afford the chiral Vanadium(V) compounds with the V=N bond, wherein a chiral dimeric structure was formed in a crystalline state through the µ-alkoxido-bridging. MoreoVer, these chiral imido and hydrazido Vanadium(V) compounds were demonstrated to dimerize by self-association at −80 °C eVen in a solution state.
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Controlled coordination in Vanadium(V) dimethylhydrazido compounds
Journal of inorganic biochemistry, 2016Co-Authors: Takashi Sakuramoto, Toshiyuki Moriuchi, Toshikazu HiraoAbstract:The Vanadium(V) dimethylhydrazido compounds were structurally characterized to elucidate the effect of the alkoxide ligands in the coordination enVironment of Vanadium(V) hydrazido center. The single-crystal X-ray structure determination of the Vanadium(V) dimethylhydrazido compound with isopropoxide ligands reVealed a dimeric structure with the V(1)-N(1) distance of 1.680(5)A, in which each Vanadium atom is coordinated in a distorted trigonal-bipyramidal geometry (τ5=0.81) with the hydrazido and bridging isopropoxide ligands in the apical positions. On the contrary, nearly tetrahedral arrangement around the Vanadium metal center (τ4=0.06) with the V(1)-N(1) distance of 1.660(2)A was obserVed in the Vanadium(V) dimethylhydrazido compound with tert-butoxide ligands. The introduction of the 2,2',2″-nitrilotriethoxide ligand led to a pseudo-trigonal-bipyramidal geometry (τ5=0.92) at the Vanadium center with the V(1)-N(1) distance of 1.691(5)A, wherein Vanadium atom is pulled out of the plane formed by the nitrilotriethoxide oxygen atoms in the direction of the hydrazido nitrogen. The coordination from the apical ligand in the Vanadium(V) dimethylhydrazido compound was found to result in the longer V(1)-N(1) distance.
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Synthesis of Vanadium(V) hydrazido complexes with tris(2-hydroxyphenyl)amine ligands.
Dalton transactions (Cambridge England : 2003), 2013Co-Authors: Toshiyuki Moriuchi, Kousuke Ikeuchi, Toshikazu HiraoAbstract:The reaction of the oxidoVanadium(V) complexes with N,N-dimethylhydrazine was demonstrated to afford the corresponding Vanadium(V) dimethylhydrazido complexes. The substituent at the 3-position of the tris(2-hydroxyphenyl)amine ligand was found to influence the electronic enVironment of the Vanadium center. The crystal structure of the non-substituted Vanadium(V) dimethylhydrazido complex exhibited a distorted trigonal bipyramidal geometry with phenolate oxygen atoms in equatorial positions and the near-linear V(1)–N(2)–N(3) angle. The Vanadium(V) diphenylhydrazido complexes could be obtained by the reaction of the oxidoVanadium(V) complexes with N,N-diphenylhydrazine. A distorted trigonal bipyramidal geometry with phenolate oxygen atoms in equatorial positions was also obserVed in the crystal structure of the non-substituted Vanadium(V) diphenylhydrazido complex.
Toshiyuki Moriuchi - One of the best experts on this subject based on the ideXlab platform.
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Structural Characterization of (Arylimido)Vanadium(V) Compounds with 2,6-Difluorophenoxide Ligand
Zeitschrift für anorganische und allgemeine Chemie, 2017Co-Authors: Toshiyuki Moriuchi, Takashi Sakuramoto, Masafumi Nishina, Ryota Kawai, Toshikazu HiraoAbstract:The (arylimido)Vanadium(V) compound, [(p-MeOC6H4N)V(OiPr)3] was demonstrated to undergo ligand exchange reaction with one or two equiValents of 2,6-difluorophenol, affording the (arylimido)Vanadium(V) compounds, [(p-MeOC6H4N)V(OiPr)2(O-2,6-F2Ph)] and [(p-MeOC6H4N)V(OiPr)(O-2,6-F2Ph)2]. Their X-ray crystallographic analyses elucidated the μ-isopropoxido-bridged dimeric structures, wherein each Vanadium atom has a trigonal-bipyramidal arrangement with the imido and bridging isopropoxide ligands in the apical positions. The isopropoxide ligand was selectiVely employed as a bridging ligand between two central Vanadium atoms. On the other hand, the reaction of the (arylimido)Vanadium(V) compound, [(p-MeOC6H4N)VCl3] and three equiValents of lithium 2,6-difluorophenoxide gaVe the (arylimido)Vanadium(V) compound, [(p-MeOC6H4N)V(O-2,6-F2Ph)3]. In the crystal packing, the thus-obtained compound showed a distorted trigonal-bipyramidal enVironment at the Vanadium atoms with the μ-phenoxido-bridged dimeric structure, wherein the 2,6-difluorophenoxide ligand was found to serVe as a bridging ligand.
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Structural Characterization of (Diphenylhydrazido)Vanadium(V) Compounds
ChemistrySelect, 2017Co-Authors: Takashi Sakuramoto, Toshikazu Hirao, Toshiyuki MoriuchiAbstract:(Diphenylhydrazido)Vanadium(V) triisopropoxide was synthesized by the reaction of VO(OiPr)3 with N,N-diphenylhydrazine. The μ-isopropoxido-bridged dimeric structure was obserVed in the molecular structure of (diphenylhydrazido)Vanadium(V) triisopropoxide. The near-linear V(1)-N(1)-N(2) angle of 173.7(3)° with the V(1)-N(1) distance of 1.667(4) A indicates that the imido nitrogen has large participation of an sp-hybridized character. The phenyl substituents of the hydrazido moiety were found to conjugate with the N−N bond. Furthermore, CH-π intermolecular interaction between two benzene rings was obserVed to induce polymeric structure in a solid state. (Diphenylhydrazido)Vanadium(V) nitrilotriethoxide was obtained by the treatment of (diphenylhydrazido)Vanadium(V) triisopropoxide with 2,2′,2′′-nitrilotriethanol. The slightly increased imido angle (V(1)-N(1)-N(2), 176.4(5)°) was obserVed as compared with (diphenylhydrazido)Vanadium(V) triisopropoxide probably because of the apical coordination of the nitrogen.
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Structural Characterization of Chiral Vanadium(V) Compounds with V=N Bond
Chemistry Letters, 2017Co-Authors: Takashi Sakuramoto, Toshikazu Hirao, Toshiyuki MoriuchiAbstract:(R)-(+)-1-Phenylethoxide ligands were introduced into (4-methoxyphenylimido)Vanadium(V) or (dimethylhydrazido)Vanadium(V) compound to afford the chiral Vanadium(V) compounds with the V=N bond, wherein a chiral dimeric structure was formed in a crystalline state through the µ-alkoxido-bridging. MoreoVer, these chiral imido and hydrazido Vanadium(V) compounds were demonstrated to dimerize by self-association at −80 °C eVen in a solution state.
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Controlled coordination in Vanadium(V) dimethylhydrazido compounds
Journal of inorganic biochemistry, 2016Co-Authors: Takashi Sakuramoto, Toshiyuki Moriuchi, Toshikazu HiraoAbstract:The Vanadium(V) dimethylhydrazido compounds were structurally characterized to elucidate the effect of the alkoxide ligands in the coordination enVironment of Vanadium(V) hydrazido center. The single-crystal X-ray structure determination of the Vanadium(V) dimethylhydrazido compound with isopropoxide ligands reVealed a dimeric structure with the V(1)-N(1) distance of 1.680(5)A, in which each Vanadium atom is coordinated in a distorted trigonal-bipyramidal geometry (τ5=0.81) with the hydrazido and bridging isopropoxide ligands in the apical positions. On the contrary, nearly tetrahedral arrangement around the Vanadium metal center (τ4=0.06) with the V(1)-N(1) distance of 1.660(2)A was obserVed in the Vanadium(V) dimethylhydrazido compound with tert-butoxide ligands. The introduction of the 2,2',2″-nitrilotriethoxide ligand led to a pseudo-trigonal-bipyramidal geometry (τ5=0.92) at the Vanadium center with the V(1)-N(1) distance of 1.691(5)A, wherein Vanadium atom is pulled out of the plane formed by the nitrilotriethoxide oxygen atoms in the direction of the hydrazido nitrogen. The coordination from the apical ligand in the Vanadium(V) dimethylhydrazido compound was found to result in the longer V(1)-N(1) distance.
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Synthesis of Vanadium(V) hydrazido complexes with tris(2-hydroxyphenyl)amine ligands.
Dalton transactions (Cambridge England : 2003), 2013Co-Authors: Toshiyuki Moriuchi, Kousuke Ikeuchi, Toshikazu HiraoAbstract:The reaction of the oxidoVanadium(V) complexes with N,N-dimethylhydrazine was demonstrated to afford the corresponding Vanadium(V) dimethylhydrazido complexes. The substituent at the 3-position of the tris(2-hydroxyphenyl)amine ligand was found to influence the electronic enVironment of the Vanadium center. The crystal structure of the non-substituted Vanadium(V) dimethylhydrazido complex exhibited a distorted trigonal bipyramidal geometry with phenolate oxygen atoms in equatorial positions and the near-linear V(1)–N(2)–N(3) angle. The Vanadium(V) diphenylhydrazido complexes could be obtained by the reaction of the oxidoVanadium(V) complexes with N,N-diphenylhydrazine. A distorted trigonal bipyramidal geometry with phenolate oxygen atoms in equatorial positions was also obserVed in the crystal structure of the non-substituted Vanadium(V) diphenylhydrazido complex.
Lina Wang - One of the best experts on this subject based on the ideXlab platform.
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a noVel synergistic extraction method for recoVering Vanadium V from high acidity chloride leaching liquor
Separation and Purification Technology, 2016Co-Authors: Guozhi Zhang, Desheng Chen, Wei Zhao, Hongxin Zhao, Lina WangAbstract:Abstract A selectiVe synergistic extraction process for recoVering Vanadium (V) from the high-acidity chloride leaching liquor was proposed. Vanadium (V) extraction from the simulated high-acidity leaching liquor with numerous impurities using a mixed extractant consisting of tricaprylmethylammonium chloride (Aliquat 336) and tri-n-butyl phosphate (TBP) was studied while obVious synergism was found. According to synergistic enhancement coefficient and physical property of organic phase, the suitable extractant composition was the Volume ratio of Aliquat 336 to TBP 1:4. The Vanadium (V) extraction increased sharply as HCl concentration increased from 1.01 mol/L to 4.13 mol/L. Under the optimum extraction conditions (extractant concentration of 50 Vol%, 1 min, 25–30 °C, and phase ratio (O/A) of 1:1), the Vanadium extraction with three stages was aboVe 90.0%. Almost no other impurity ions, such as Ca, Al, Mg, Cr, Ti, Mn, and Si, were co-extracted. Under the optimum stripping conditions, the Vanadium stripping was aboVe 92.0% in a single stage using water as the effectiVe stripping reagent. High-quality V2O5 product was obtained after precipitation and calcination. The mechanism of Vanadium (V) extraction by Aliquat 336–TBP mixed extractant was discussed based on the analysis of FT-IR and UV–Vis spectra.
Gérard Cote - One of the best experts on this subject based on the ideXlab platform.
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Speciation of Vanadium (V) extracted from acidic sulfate media by trioctylamine in n-dodecane modified with 1-tridecanol
Hydrometallurgy, 2010Co-Authors: Alexandre Chagnes, Marie-noëlle Rager, Bruno Courtaud, Jacques Thiry, Gérard CoteAbstract:Abstract The speciation of Vanadium (V) extracted from acidic sulfate media by protonated trioctylamine in n-dodecane modified with 5% (wt) 1-tridecanol has been inVestigated by Fourier transformed infrared spectroscopy (FTIR) and 51V nuclear magnetic resonance spectroscopy (51V NMR). In aqueous sulfate solutions, Vanadium (V) exists both as VO2+ and VO2SO4− ions. The FTIR spectra of 0.2 mol kg− 1 protonated trioctylamine in n-dodecane modified with 5% (wt) 1-tridecanol, loaded with Various concentrations of Vanadium (V) by extraction from 1 mol kg− 1 H2SO4, indicate that Vanadium (V) exists in organic phases as polyVanadates, likely as decaVanadates. The condensed nature of the extracted form of Vanadium (V) was neither confirmed nor precluded by 51V NMR as the micellar structure of these organic phases imposes local conditions which allow the transformation of VO2+ and VO2SO4− into polyVanadates, but also modify the chemical shifts compared to the ones obserVed in bulk aqueous solutions for mononuclear and polynuclear Vanadium (V) species.
