Sutradhar Manas, Mukherjee Gurunath, Drew Michael G B, Ghosh Saktiprosad
Department of Chemistry, University of Calcutta, University College of Science, 92 Acharya Prafulla Chandra Road, Kolkata 700 009, India.
Inorg Chem. 2006 Jun 26;45(13):5150-61. doi: 10.1021/ic051120g.
Reaction of the tridentate ONO Schiff-base ligand 2-hydroxybenzoylhydrazone of 2-hydroxybenzoylhydrazine (H2L) with VO(acac)2 in ethanol medium produces the oxoethoxovanadium(V) complex [VO(OEt)L] (A), which reacts with pyridine to form [VO(OEt)L.(py)] (1). Complex 1 is structurally characterized. It has a distorted octahedral O4N2 coordination environment around the V(V) acceptor center. Both complexes A and 1 in ethanol medium react with neutral monodentate Lewis bases 2-picoline, 3-picoline, 4- picoline, 4-amino pyridine, imidazole, and 4-methyl imidazole, all of which are stronger bases than pyridine, to produce dioxovanadium(V) complexes of general formula BH[VO2L]. Most of these dioxo complexes are structurally characterized, and the complex anion [VO2L]- is found to possess a distorted square pyramidal structure. When a solution/suspension of a BH[VO2L] complex in an alcohol (ROH) is treated with HCl in the same alcohol, it is converted into the corresponding monooxoalkoxo complex [VO(OR)L], where R comes from the alcohol used as the reaction medium. Both complexes A and 1 produce the 4,4'-bipyridine-bridged binuclear complex [VO(OEt)L]2(mu-4,4'-bipy) (2), which, to the best of our knowledge, represents the first report of a structurally characterized 4,4'-bipyridine-bridged oxovanadium(V) binuclear complex. Two similar binuclear oxovanadium(V) complexes 3 and 4 are also synthesized and characterized. All these binuclear complexes (2-4), on treatment with base B, produce the corresponding mononuclear dioxovanadium(V) complexes (5-10).
三齿ONO席夫碱配体2-羟基苯甲酰肼（H2L）与VO(acac)2在乙醇介质中反应生成氧代乙氧基钒（V）配合物[VO(OEt)L]（A），该配合物与吡啶反应形成[VO(OEt)L·(py)]（1）。对配合物1进行了结构表征。它在V（V）受体中心周围具有扭曲的八面体O4N2配位环境。乙醇介质中的配合物A和1都与中性单齿路易斯碱2-甲基吡啶、3-甲基吡啶、4-甲基吡啶、4-氨基吡啶、咪唑和4-甲基咪唑反应，所有这些碱都比吡啶碱性更强，生成通式为BH[VO2L]的二氧代钒（V）配合物。对这些二氧代配合物中的大多数进行了结构表征，发现配合物阴离子[VO2L]-具有扭曲的四方锥结构。当BH[VO2L]配合物在醇（ROH）中的溶液/悬浮液用同一醇中的HCl处理时，它会转化为相应的单氧代烷氧基配合物[VO(OR)L]，其中R来自用作反应介质的醇。配合物A和1都生成了4,4'-联吡啶桥联的双核配合物[VO(OEt)L]2(μ-4,4'-bipy)（2），据我们所知，这是关于结构表征的4,4'-联吡啶桥联氧代钒（V）双核配合物的首次报道。还合成并表征了另外两个类似的双核氧代钒（V）配合物3和4。所有这些双核配合物（2 - 4）在用碱B处理时，会生成相应的单核二氧代钒（V）配合物（5 - 10）。
