13470-26-3Relevant articles and documents
Low-temperature Syntheses of Vanadium(III) and Molybdenum(IV) Bromides by Halide Exchange
Calderazzo, Fausto,Maichle-Moessmer, Caecilie,Pampaloni, Guido,Straehle, Joachim
, p. 655 - 658 (1993)
Halide-exchange reactions of VCl4 or MoCl5 with dry HBr at temperatures between ca. -50 and +20 deg C afforded the corresponding bromides, VBr3 or MoBr4, in good yields, presumably via the formation of unstable higher-valent bromide intermediates which undergo spontaneous loss of bromine.In corresponding reactions with HI the exchange was incomplete and mixed halides were obtained.At room temperature the VCl4-HI system gave VCl3 in an almost quantitative yield.By reaction of MoBr4 with tetrahydrofuran (thf) was isolated and its crystal structure determined: orthorhombic, space group Pbcn (no. 60), a = 8.812(2), b = 13.882(5), c = 14.279(3) Angstroem, Z = 4, R = 0.063.The molecule has the usual meridional geometry, typical of other derivatives (X = Cl or I).
Transport reactions of some vanadium(III) halides. Mixed halide formation
Mccarley, Robert E.,Roddy, James W.,Berry, Keith O.
, p. 50 - 54 (1964)
The reactions of VCl2, VCl3, and VCl3-VBr3 mixtures with bromine vapor at 350 to 450° led to vaporization of the halides and deposition of mixed halides of vanadium(III) at lower temperatures. A study of solid solution formation in the system VCl3-VBr3 showed that the two components were miscible in the solid state, and that the mixed halide VCl2Br should be regarded as such a solid solution. The pure compounds VCl3 and VBr3, the mixed halides VCl2Br and VBr2I, and solutions of all compositions in the system VCl3-VBr3 were hexagonal solids with the BiI3 layer structure; lattice constants for all of the compounds are given. Vaporization of VBr2 in iodine vapor at 350 to 400° resulted in the transport and deposition of VBr2I, but the analogous reaction between VCl2 and iodine yielded only a deposit of VCl2. Vanadium(IV) mixed halides containing iodine were postulated to account for the vaporization at these temperatures.
Preparations, structures, and properties of sulfato-bridged dinuclear and tetranuclear vanadium(III) complexes with a dinucleating ligand, 2-oxo-N,N′-bis(2-pyridylmethyl)-1,3-propanediamine-N,N′-diacetate
Kanamori, Kan,Matsui, Naoto,Takagi, Kentaro,Miyashita, Yoshitaro,Okamoto, Ken-Ichi
, p. 1881 - 1888 (2006)
New dinuclear and tetranuclear vanadium(III) complexes with sulfato bridge(s), [{VIII(H2O)}2(μ-hpnbpda)-(μ- OH)(μ-SO4)]·5.25H2O (1) and [V III4(μ-hpnbpda)2(μ-OH) 2(μ-SO4)2]·12H2O (2), where hpnbpda is an alkoxobridging dinucleating ligand, 2-oxo-N,N′-bis(2- pyridylmethyl)-1,3-propanediamine-N,N′-diacetate, were prepared, and their structures were determined by X-ray crystallography. The vanadium(III) center in 1 adopts heptacoordinate structure while that in 2 has a hexacoordinate structure. In 2, the two dinuclear vanadium(III) units bridged by the alkoxo group of hpnbpda are further linked by two hydroxo and two sulfato bridging groups, resulting in a dimer-of-dimers structure. Measurement of the temperature dependence of the magnetic susceptibility of 1 revealed that the two vanadium(III) ions are antiferromagnetically coupled with J = -5.9 cm -1 and g = 1.90.
Vaporization reactions of vanadium(III) bromide. Dissociation and disproportionation equilibria, and the formation of vanadium(IV) bromide
Mccarley, Robert E.,Roddy, James W.
, p. 54 - 59 (1964)
The equilibria VBr3(s) = VBr2(s) + 1/2Br2(g) (1) and 2VBr3(s) = VBr2(s) + VBr4(g) (2) were studied over the range 644 to 805°K. by transpiration in helium. For (1) ΔH° = 23.1 ± 0.9 kcal./mole and ΔS° = 10.6 ± 0.4 e.u., while for (2) ΔH° = 37.7 ± 1.3 kcal./mole and ΔS° = 34.7 ± 1.2 e.u. Both transpiration in bromine vapor and static pressure measurements using a glass diaphragm gage showed that VBr3(s) vaporized as VBr4(g) in the presence of bromine according to VBr3(s) + 1/2Br2(g) = VBr4(g) (3). The transpiration measurements gave for (3) ΔF° = 15.80 × 103 - 23.9T for T = 515-585°K. Solid VBr4 was isolated by condensation of the vapor at -78° and was found to be stable at -45°. At higher temperatures the solid decomposed to VBr3(s) and bromine.
Heptacoordinate vanadium(III) complexes containing a didentate sulfate ligand. X-ray structures of [V2(SO4)3{N, N′-bis(2-pyridylmethyl)-1,2-ethanediamine}2] and [V(SO4){N,N,N′, N′-tetrakis(2-pyridylmethyl)-1,2-ethanediamine}]+ and their solution properties
Kanamori, Kan,Kameda, Eiji,Okamoto, Ken-Ichi
, p. 2901 - 2909 (1996)
Several vanadium(III) complexes with a tetradentate N,N′-bis(2-pyridylmethyl)-1,2-ethanediamine (bispicen) or a hexadentate N,N,N′,N′-tetrakis(2-pyridylmethyl)-1,2-ethanediamine (tpen) ligand were prepared and characterized by UV-vis and Raman spectroscopy. Of these complexes, the structures of two vanadium(III) complexes with a didentate sulfate were determined by X-ray crystallography. [V2(SO4)3(bispicen)2] crystallizes in the monoclinic space group ClIc with a=25.083(7), b=24.236(5), c=15.708(5) A, β=114.96(2)°, Z=8, and R=0.087. The complex containing the [V(SO4)-(tpen)+ cation crystallizes in the orthorhombic space group Aba2 with a=20.1836(8), b=19.793(1), c=15.6107(7) A, Z=8, and R=0.069. Both complexes adopt a heptacoordinate pentagonal bipyramidal structure in which the didentate sulfate is situated in the pentagonal plane. The heptacoordinate structure of the tpen-SO42- complex is stable in an aqueous solution, whereas the bispicen-SO42- complex is easily aquated to yield a hexacoordinate oxo-bridged dinuclear species.
Redox reactions with bis(η6-arene) derivatives of early transition metals
Calderazzo, Fausto,Englert, Ulli,Pampaloni, Guido,Volpe, Manuel
, p. 3321 - 3332 (2007/10/03)
The reactivity of M(η6-arene)2 derivatives of early transition metals (M = Ti, Cr, Mo, arene = MeC6H5; M = V, Nb, arene = 1,3,5-Me3C6H3) has been investigated and the syntheses of new and known compounds are described. The derivatives M(CH3COO)3, M = Ti, V, Nb, Cr; M(CF 3COO)3, M = Ti, Nb, Cr; M(acac)3, M = Ti, V, Mo, acac = acetylacetonato, and M(F6acac)3, F 6acac = hexafluoroacetylacetonato, M = V, Nb have been prepared by reaction of the metal bis(arene) derivatives with the appropriate Lewis acid. The crystal and molecular structure of V(F6acac)3 has been determined. Hydrogen halides or halogens react with M(η6-arene) 2 with formation of metal halides, a highly reactive form of VCl 3 being obtained from V(η6-1,3,5-Me3C 6H3)2 and hydrogen chloride in heptane. TiCl4 oxidizes Ti(η6-arene)2 with complete loss of the arene ligands. An electron transfer process affording ionic derivatives of formula [M(η6-MeC6H5) 2][TiCl4(THF)2], M = Cr (structurally characterized), Mo, has been observed between the THF-adduct of TiCl4 and the appropriate metal-arene derivative of Group 6.
Syntheses, Characterization, and Properties of Vanadium(III) Complexes Containing Tripodal Tetradentate Ligands with Single Pyridyl Groups
Kanamori, Kan,Kameda, Eiji,Kabetani, Takatsugu,Suemoto, Taiko,Okamoto, Ken-ichi,Kaizaki, Sumio
, p. 2581 - 2590 (2007/10/03)
The syntheses, characterization, and properties of (1a), (1b), (2), and Br2 (3) are described, where pda (N-(2-pyridylmethyl)iminodiacetate), bpg (N,N-bis(2-pyridylmethyl)glycinate), and tpa (tris(2-pyridylmethyl)amine) are tripodal tetradentate ligands with single pyridyl groups.Complexes 1a, 1b, and 2 were characterized on the basis of their electronic and Raman spectra.The structure of 3 was determined by X-ray crystallography.Complex 3 crystallizes in the P space group with the following unit cell dimensions: a=11.505(5), b=11.509(5), c=16.348(7) Angstroem, α=103.73(2) deg, β=103.71(2) deg, γ=93.26(3) deg, and Z=2.The V-O-V angle is 175.3(2) deg and the V-μ-O distances are 1.783(2) and 1.784(2) Angstroem.In complex 3, the four unpaired electrons are ferromagnetically coupled.It was found that there is a positive correlation between 2 * νas(V-O-V) and the energy of the oxo-to- V(III) charge-transfer transition for single oxo-bridged dinuclear vanadium(III) complexes including the present complexes.This correlation is discussed in terms of the ? character of the V(III)-μ-O bond that is affected by the remaining donor groups.
