New sulfate-bridged dinuclear oxidovanadium complexes

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• 作者：Evgenia S. Bazhina ; Marina E. Nikiforova ; Grigory G. Aleks ; rov ; Nikolay N. Efimov ; Helena A. Ugolkova ; Oleg M. Nikitin ; Tatiana V. Magdesieva ; Artem S. Bogomyakov ; Vadim V. Minin ; Aleksei A. Sidorov ; Vladimir M. Novotortsev ; Igor L. Eremenko
• 关键词：Oxidovanadium(IV) ; Chelate complexes ; 4 ; 4&prime ; -Di-tert-butyl-2 ; 2&prime ; -bipyridine ; X-ray diffraction ; ESR spectroscopy ; Cyclic voltammetry
• 刊名：Inorganica Chimica Acta
• 出版年：2012
• 出版时间：30 September, 2012
• 年：2012
• 卷：392
• 期：Complete
• 页码：192-198
• 全文大小：637 K

文摘

The reaction of oxidovanadium sulfate VOSO₄¡¤3H₂O with 4,4¡ä-di-tert-butyl-2,2¡ä-bipyridine (dtb-bpy) in methanol was found to give the complex (VO)₂(¦Ì₂-SO₄)₂(dtb-bpy)₂(CH₃OH)₂¡¤4CH₃OH (lass=""boldFont"">1). Single crystal X-ray diffraction reveals that molecule lass=""boldFont"">1 is a centrosymmetric dimer consisting of two {VO(¦Ì₂-SO₄)(dtb-bpy)(CH₃OH)} moieties linked by two bridging sulfate anions. Each vanadium atom is in a distorted octahedral environment formed by two nitrogen and four oxygen atoms. The further reaction of an ethanolic solution of compound lass=""boldFont"">1 with sodium pivalate in CH₃CN produces the new dinuclear complex [(VO)₂(¦Ì₂-O)₂(¦Ì₂-SO₄)(dtb-bpy)₂]¡¤2CH₃CN (lass=""boldFont"">2), which does not include pivalate ligands, but contains one bridging sulfate anion and two bridging oxygen atoms. The X-ray study, cyclic voltammetry and magnetic measurements were performed allowing to conclude that both vanadium centers in lass=""boldFont"">2 are in +5 oxidation state. According to ESR studies the dinuclear complex lass=""boldFont"">1 undergoes dissociation upon dissolution in ethanol yielding mononuclear species VO(¦Ì₂-SO₄)(dtb-bpy)(CH₃OH), while solution of lass=""boldFont"">1 in dichloromethane contains ¡°dimers¡± exhibiting spin-spin exchange interactions between two paramagnetic monomeric fragments.