Mercury Complexes of N-Heterocyclic Carbenes Derived from Imidazolium-Linked Cyclophanes: Synthesis, Structure, and Reactivity

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• 作者：Murray V. Baker ; David H. Brown ; Rosenani A. Haque ; Peter V. Simpson ; Brian W. Skelton ; Allan H. White ; Charlotte C. Williams
• 刊名：Organometallics
• 出版年：2009
• 出版时间：July 13, 2009
• 年：2009
• 卷：28
• 期：13
• 页码：3793-3803
• 全文大小：934K
• 年卷期：v.28,no.13(July 13, 2009)
• ISSN：1520-6041

文摘

A range of mercury-imidazolylidene complexes have been prepared by reaction of imidazolium-linked cyclophanes with mercury(II) acetate. For cyclophanes based on meta-xylyl groups the mercury complexes are mononuclear and exhibit unprecedented structures in which the mercury atom is bound within the cyclophane ring, the two NHC donors being mutually trans. For cyclophanes based on ortho-xylyl or 2,6-lutidinediyl groups the mercury complexes are dinuclear with a [Hg(μ-L)₂Hg] core, in which each mercury atom is coordinated by one NHC from each cyclophane unit. The mononuclear and dinuclear complexes have been structurally characterized. Studies of the NHC-pyridinophane mercury complex indicated that the NHC−Hg bonding is labile, suggesting that the dinuclear complex based on the [Hg(μ-L)₂Hg] core existed in equilibrium with a mononuclear complex [HgL]. The labile nature of the NHC−Hg bonding was further established by a redox transmetalation reaction of a dinuclear NHC-Hg(II) complex with a Pd(0) source, which afforded an NHC-Pd(II) complex.