Mononuclear NiIII−Alkyl Complexes (Alkyl = Me and Et): Relevance to the Acetyl-CoA Synthase and Methyl-CoM Reductase

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• 作者：Chien-Ming Lee ; Chien-Hong Chen ; Fu-Xing Liao ; Ching-Han Hu ; Gene-Hsiang Lee
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：July 14, 2010
• 年：2010
• 卷：132
• 期：27
• 页码：9256-9258
• 全文大小：177K
• 年卷期：v.132,no.27(July 14, 2010)
• ISSN：1520-5126

文摘

Mononuclear, distorted trigonal bipyramidal [PPN][Ni^III(R)(P(C₆H₃-3-SiMe₃-2-S)₃)] (R = Me (1); R = Et (2)) were prepared by reaction of [PPN][Ni^IIICl(P(C₆H₃-3-SiMe₃-2-S)₃)] and CH₃MgCl/C₂H₅MgCl, individually. EPR, SQUID studies as well as DFT computations reveal that the Ni^III in 1 has a low-spin d⁷ electronic configuration in a distorted trigonal bipyramidal ligand field. The Ni−C bond lengths of 1.994(3) Å in 1 and 2.015(3) Å in 2 are comparable to that in the Ni^III−methyl state of MCR (2.04 Å) (Sarangi, R.; Dey, M.; Ragsdale, S. W. Biochemistry 2009, 48, 3146). Under a CO atmosphere, CO triggers homolytic cleavage of the Ni^III−CH₃ bond in 1 to produce Ni^II−thiolate carbonyl [PPN][Ni^II(CO)(P(C₆H₃-3-SiMe₃-2-S)₃)] (3). Additionally, protonation of 1 with phenylthiol generates Ni^III−thiolate [PPN][Ni^III(SPh)(P(C₆H₃-3-SiMe₃-2-S)₃)] (4).