Synthesis and Reactivity of Manganese(II) Complexes Containing N-Heterocyclic Carbene Ligands
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- 作者：Malik H. Al-Afyouni ; V. Mahesh Krishnan ; Hadi D. Arman ; Zachary J. Tonzetich
- 刊名：Organometallics
- 出版年：2015
- 出版时间：October 26, 2015
- 年：2015
- 卷：34
- 期：20
- 页码：5088-5094
- 全文大小：473K
- ISSN：1520-6041
文摘
A series of manganese(II) complexes containing aryl-substituted N-heterocyclic carbene (NHC) ligands have been synthesized and characterized. Chloride complexes of Mn(II) containing the NHC ligands 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) and 1,3-dimesitylimidazol-2-ylidene (IMes) were prepared in straightforward fashion by direct carbene addition to MnCl2(THF)1.6. These complexes exist as chloride-bridged dimers in solution of formula [Mn2Cl2(渭-Cl)2(NHC)2]. The monomeric complex [MnCl2(IMes)2] has also been prepared and structurally characterized, although NMR studies are consistent with facile dissociation of one of the IMes ligands in solution. [Mn2Cl2(渭-Cl)2(IPr)2] serves as a precursor to dimeric alkyl and aryl compounds of Mn(II) including [Mn2R2(渭-Cl)2(NHC)2] (R = Bn, o-tolyl, and Ph) and the bridging methyl complex [Mn2Me2(渭-Me)2(IPr)2]. Stoichiometric reactions of these hydrocarbyl species with bromocyclohexane demonstrate that they are not chemically competent in C鈥揅 coupling reactions involving alkyl electrophiles.