School of Chemistry, University of St Andrews, St Andrews, UK KY16 9ST.
Dalton Trans. 2009 Sep 21(35):6967-71. doi: 10.1039/b907109a. Epub 2009 Jun 26.
The compounds 4,5-dimethyl-N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene silver chloride [AgCl(IPr(Me))] and 4,5-dimethyl-N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene gold(I) chloride [AuCl(IPr(Me))] have been synthesized. The attempted synthesis of the corresponding 4,5-dimethyl-N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene gold(III) chloride by oxidative addition of chlorine gas on allowed for the formation of the expected complex, concomitantly with , resulting from a chlorination of a methyl group situated in the backbone of the NHC (N-heterocyclic carbene). Additionally, the buried volume %V(bur) of the IPr(Me) ligand in [AgCl(IPr(Me))] and [AuCl(IPr(Me))] complexes was calculated and compared to %V(bur) of more classical NHCs. This quantification of the steric hinderance of the IPr(Me) ligand reveals the influence of the substituent modulation in the backbone of NHCs.
已经合成了化合物 4,5-二甲基-N,N'-双(2,6-二异丙基苯基)咪唑-2-亚基氯化银[AgCl(IPr(Me))]和 4,5-二甲基-N,N'-双(2,6-二异丙基苯基)咪唑-2-亚基氯化金(I)[AuCl(IPr(Me))]。通过向反应体系中通入氯气尝试合成相应的 4,5-二甲基-N,N'-双(2,6-二异丙基苯基)咪唑-2-亚基氯化金(III)，同时得到了预期的配合物，这是由于 NHC（氮杂环卡宾）骨架上的一个甲基发生了氯化反应。此外，还计算并比较了[AgCl(IPr(Me))]和[AuCl(IPr(Me))]配合物中 IPr(Me)配体的掩埋体积%V(bur)与更经典的 NHC 的%V(bur)。这种对 IPr(Me)配体空间位阻的定量分析揭示了 NHC 骨架中取代基调制的影响。
