钒（V）酒石酸配合物：H3O+(OH-)/H2VO4-/(2R,3R)-酒石酸体系中的物种形成以及Na4[V4O8(rac-酒石酸)2].12H2O和(NEt4)4[V4O8((R,R)-酒石酸)2].6H2O（酒石酸 = C4H2O6(4-)）的X射线晶体结构

Vanadium(V) tartrato complexes: speciation in the H3O+(OH-)/H2VO4-/(2R,3R)-tartrate system and X-ray crystal structures of Na4[V4O8(rac-tart)2].12H2O and (NEt4)4[V4O8((R,R)-tart)2].6H2O (tart = C4H2O6(4-)).

作者信息

Schwendt Peter, Tracey Alan S, Tatiersky Jozef, Gáliková Jana, Zák Zdirad

机构信息

Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, MlynskA dolina, Bratislava 84215, Slovak Republic.

出版信息

Inorg Chem. 2007 May 14;46(10):3971-83. doi: 10.1021/ic062223h. Epub 2007 Apr 10.

DOI:10.1021/ic062223h

PMID:17419617

Abstract

A study of the aqueous H3O+(OH-)/H2VO4-/(2R,3R)-tartrate system has been performed at 273 K in a 1.0 mol/L Na+(Cl-) ionic medium using 51V NMR spectroscopy. In this relatively complicated system, more than 12 different species were observed. Ligand concentration, vanadate concentration, and pH variation studies were carried out, particularly for the range of pH 5.8-8.0 and for pH 2.4. Chemical shifts, vanadium-ligand stoichiometry, and also composition and formation constants for some, but not all, species are given. Despite some reduction of vanadium(V) to vanadium(IV) in an acidic medium at pH approximately 2.4, the stoichiometries of the principal species in solution at this pH were determined. Electrospray ionization mass spectra for some solutions were obtained and were in accordance with the conclusions drawn from the speciation studies. A series of crystalline vanadium(V) tartrato complexes M4[V4O8(tart)2].aq were also prepared and characterized. X-ray diffraction studies of Na4[V4O8(rac-tart)2].12H2O (1) and (NEt4)4[V4O8((R,R)-tart)2].6H2O (2) revealed unique tetranuclear [V4O8(tart)2]4- ions for which the {V4O4} rings have boat conformations.

摘要

利用(^{51}V)核磁共振光谱法，在(273K)、(1.0mol/L Na^{+}(Cl^{-}))离子介质中对水相(H_3O^{+}(OH^{-})/H_2VO_4^{-}/(2R,3R))-酒石酸盐体系进行了研究。在这个相对复杂的体系中，观察到了超过12种不同的物种。进行了配体浓度、钒酸盐浓度和pH变化研究，特别是在pH 5.8 - 8.0范围以及pH 2.4时。给出了一些（但不是全部）物种的化学位移、钒-配体化学计量比以及组成和形成常数。尽管在pH约为2.4的酸性介质中钒(V)有部分还原为钒(IV)，但仍确定了该pH下溶液中主要物种的化学计量比。获得了一些溶液的电喷雾电离质谱，其结果与物种形成研究得出的结论一致。还制备并表征了一系列结晶钒(V)酒石酸盐配合物(M_4[V_4O_8(tart)_2]\cdot aq)。对(Na_4[V_4O_8(rac - tart)_2]\cdot12H_2O) (1)和((NEt_4)_4[V_4O_8((R,R)-tart)_2]\cdot6H_2O) (2)进行的X射线衍射研究揭示了独特的四核([V_4O_8(tart)_2]^{4 - })离子，其({V_4O_4})环具有船式构象。