Hexanickel Enediolate Cluster Generated in an Acireductone Dioxygenase Model Reaction

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• 作者：Katarzyna Rudzka ; Katarzyna Grubel ; Atta M. Arif ; Lisa M. Berreau
• 刊名：Inorganic Chemistry
• 出版年：2010
• 出版时间：September 6, 2010
• 年：2010
• 卷：49
• 期：17
• 页码：7623-7625
• 全文大小：702K
• 年卷期：v.49,no.17(September 6, 2010)
• ISSN：1520-510X

文摘

A nickel(II) enediolate cluster (2) forms upon treatment of [(6-Ph₂TPA)Ni(PhC(O)C(OH)C(O)Ph)]ClO₄ (1) with Me₄NOH·5H₂O in CH₃CN. Crystallographic studies of 2 revealed a hexanuclear structure of S₆ symmetry with a formula of {[Ni(PhC(O)C(O)C(O)Ph)(CH₃OH)]·1.33CH₃OH}₆. Because isolation of bulk amounts of 2 from the reaction involving 1 proved impossible, a solvation analogue of 2 (labeled 5) was generated from admixture of Ni(ClO₄)₂·6H₂O, 2-hydroxy-1,3-diphenylpropane-1,3-dione, and Me₄NOH·5H₂O in CH₃OH/CH₃CN. Complex 5 is formulated as {[Ni(PhC(O)C(O)C(O)Ph)(H₂O)]·H₂O·0.25CH₃CN}₆ based on elemental analysis, a molecular weight determination, UV−vis, and a magnetic moment measurement. Treatment of 5 with O₂ and 6-Ph₂TPA (6 equiv) results in the formation of CO and [(6-Ph₂TPA)Ni(O₂CPh)₂(H₂O)] (3), the latter of which was isolated in 69% yield. The level of ¹⁸O incorporation in this reaction matches that for a reaction wherein 2 is generated from 1. These results provide evidence that a nickel(II) enediolate cluster is the O₂ reactive species in a previously reported model reaction for nickel(II)-containing acireductone dioxygenase.