Synthesis and Interconversion of V4, V7, and V8 Oxide Clusters: Unexpected Formation of Neutral Heptanuclear Oxido(alkoxido)vanadium(V) Clusters [V7O17(OR)(4,4′-tBubpy)3] (R = Et, MeOC2H4)

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• 作者：Shintaro Kodama ; Nobuto Taya ; Yuta Inoue ; Youichi Ishii
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：July 5, 2016
• 年：2016
• 卷：55
• 期：13
• 页码：6712-6718
• 全文大小：468K
• 年卷期：0
• ISSN：1520-510X

文摘

The octanuclear oxidovanadium(V) complex [V₈O₂₀(4,4′-^tBubpy)₄] (1; 4,4′-^tBubpy = 4,4′-di-tert-butyl-2,2′-bipyridine) was synthesized in multigram-scale quantities by the reaction of VOSO₄ with 4,4′-^tBubpy in the presence of sodium benzoate under O₂. The reaction of 1 with MeOH under air afforded the tetranuclear oxidovanadium(V) complex [V₄O₈(OMe)₄(4,4′-^tBubpy)₂] (2) selectively. In contrast, treatment of 1 with EtOH or MeOC₂H₄OH under air gave the heptanuclear oxidovanadium(V) complexes [V₇O₁₇(OR)(4,4′-^tBubpy)₃] (R = Et (3a), MeOC₂H₄ (3b)) having an unprecedented neutral V₇O₁₇(OR) core. Although 3a and 3b are relatively stable in CH₂Cl₂, slow diffusion of Et₂O into the solution of 3a in CH₂Cl₂ afforded 1 as yellow crystals. Complex 2 was also converted into 1 by recrystallization from CHCl₃–CH₂Cl₂/Et₂O. ¹H and ⁵¹V NMR as well as electrospray ionization mass spectrometry studies of the behavior of 2 in CD₂Cl₂ suggested the formation of the methoxido analogue of 3 (3c, R = Me), which is considered to be an intermediate species in the conversion of 2 to 1. The present results provide a rare example of interconversion among neutral vanadium(V) oxide cluster complexes by changing the solvent systems.