An Extension of the Wittig Reaction: Attack of Phosphorus Ylides at Acyl Groups in Organocobalt Complexes

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• 作者：Qibao Wang ; Hongjian Sun ; Shimin Fang ; Mingcui Liu ; Klaus Harms ; Xiaoyan Li
• 刊名：Organometallics
• 出版年：2007
• 出版时间：December 31, 2007
• 年：2007
• 卷：26
• 期：27
• 页码：6805 - 6811
• 全文大小：356K
• 年卷期：v.26,no.27(December 31, 2007)
• ISSN：1520-6041

文摘

Attack of phosphorus ylides at acyl groups in organocobalt complexes was observed. Reactions of hydrido(acylenolato) cobalt(III) complexes [Co^III(O∩CO)L₃H] (O∩CO = acylenolato ligand, L = P(CH₃)₃) 1–3 with phosphorus ylides (H₂CPPh₃, H₂CP(n-Bu)₃, CH₃CHPPh₃) afford eight novel organocobalt compounds. The structures of the eight compounds greatly differ according to the electronic and steric properties of the reactants. As a result of the Wittig reaction compounds [Co^I(O∩)L₃], 4–6 and 9 are (π-olefin)cobalt(I) compounds. Compound [Co^II(O∩CO)L₃] 8 is a stable (acylenolato)cobalt(II) complex with 17 valence electrons. The dinuclear compounds [Co^II(O∩CO)L₂]₂ 10–12 show unusual properties, as they are diamagnetic in solid state and possess centrosymmetric structures containing a [Co(μ₂-O)]₂ ring, while in solution they are mononuclear and paramagnetic. The crystal structures of the compounds 4–6, 8, 9, and 11 were determined by X-ray diffraction. The mechanisms of formation are discussed.