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Organovanadium chemistry is the chemistry of organometallic compounds containing a carbon to vanadium (V) chemical bond.〔''Synthesis of Organometallic Compounds: A Practical Guide'' Sanshiro Komiya Ed. 1997〕 Organovanadium compounds are of some relevance to organic synthesis and to polymer chemistry as reagents and catalysts. Oxidation states for vanadium are +2, +3, +4 and +5. Low valency vanadium is usually stabilized with carbonyl ligands. Oxo ligands for example in vanadyl ions are common when the valency increases. In most compounds outside the oxidation state of +5, vanadium is paramagnetic hampering NMR spectroscopy. Typical vanadium precursors are vanadium(III) chloride and its adduct with THF VCl3(THF)3 and vanadium tetrachloride. ==Synthesis== Common ligands for vanadium are carbonyl, phosphine and cyclopentadienyl. Vanadium carbonyl can be prepared from vanadium(II) chloride, vanadium oxytrichloride or vanadium acetylacetonate in reaction with carbon monoxide, pyridine and magnesium or zinc as reducing agent 〔SYNTHESIS OF VANADIUM HEXACARBONYL R. Ercoli, F. Calderazzo, A. Alberola J. Am. Chem. Soc., 1960, 82 (11), pp 2966–2967 〕 The hexacarbonylvanadate ion can be prepared in from VCl3: :4 Na + VCl3 + 6 CO + 2 diglyme → ()() + 3 NaCl Vanadocene dichloride is prepared from sodium cyclopentadienyl: : 2NaC5H5 + VCl4 → VCp2Cl2 + 2NaCl Reduction of this compound gives the parent vanadocene (Cp)2V:〔''The reduction of bis-cyclopentadienyl compounds'' J. M. Birmingham, A. K. Fischer and G. Wilkinson Naturwissenschaften Volume 42, Number 4 / January, 1955 〕 : VCp2Cl2 + LiAlH4 → V(Cp)2 Vanadocene is the first stable metallocene in the transition metals. Titanocene and zirconocene only exist as the dichlorides titanocene dichloride and zirconocene dichloride.〔''Adventures in Vanadocene Chemistry'' Robert Choukroun, and Christian Lorber Eur. J. Inorg. Chem. 2005, 4683–4692 〕 It reacts as a metal carbene to alkyne and nitrile ligands and is also used as a reducing agent. Indene can also be a ligand: : VCl3(THF)3 + Zn → ()n : VCl2(THF)]n + Na(indenyl) → V(C9H7)2 and benzene: : VCl4 + AlCl3 + C6H6 → ()() : ()() + H2O → V(η6C6H6)2 Many η1 alkyl and aryl complexes exist for example with mesitylene groups: : VCl3(THF)3 + (mes)MgBr → V(mes)3(THF) : V(mes)3(THF) + LiMes → Li() : Li() + air → V(mes)4(THF) or norbornyl groups: : VCl4 + Li(norbornyl) → V(norbornyl)4 Vanadium oxytrichloride is a starting material for vanadium(V) compounds: : VOCl3 + Li(mes) → Li() : Li() + chloranil → VO(mes)3 : VOCl3 + ZnPh2 → VOPhCl2 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Organovanadium chemistry」の詳細全文を読む スポンサード リンク
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