Formation of the 1,4-Diazabutadien-2-yl Complex [Mn(CNPh*)<sub>4</sub>{C(NPh*)C(CH<sub>3</sub>)N(Ph*)}] through Methylation of a Manganese(−I) Isonitrilate
作者:Tracy L. Utz、Patricia A. Leach、Steven J. Geib、N. John Cooper
DOI:10.1021/om970287h
日期:1997.9.1
Alkylation of [Mn(CNPh*)(5)](-) with CH3I gives the 1,4-diazabutadien-2-yl complex [Mn(CNPh*)(4)C(=NPh*)C(CH3)=N(Ph*)}] (2) in a 30% yield, as established by a single-crystal X-ray diffraction study. The same product can be obtained in poor yield when CH3OSO2CF3 is used as the alkylating agent,;Ind use of ethyl iodide gives the corresponding ethyl complex [Mn(CNPh*)(4)C(=NPh*)C(CH2CH3)=N(Ph*)}] (3). It is proposed that the first step in the formation of 2 is alkylation at manganese: transient [Mn(CNPh*)(5)CH3] is then converted into an iminoacyl complex by isonitrile/alkyl insertion. Insertion of a second isonitrile into the metal-iminoacyl bond leads to the 1,4-diazabutadien-2-yl complex. The addition of free CNPh* to the reaction solution leads to only a modest increase in the yield of 2, but the importance of exogenous isonitrile is supported by the formation of [Mn((CNBu)-Bu-t)(CNPh*)(3)C(=NPh*)C(CH3)=N(Ph*)}] (4), in which 1 equiv of (CNBu)-Bu-t is coordinated to Mn, when (CNBu)-Bu-t is added to a solution of 1(-) before reaction with CH3I.