Inorganic and Organometallic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058, Erlangen, Germany.
Angew Chem Int Ed Engl. 2017 Jun 6;56(24):6906-6910. doi: 10.1002/anie.201703037. Epub 2017 May 5.
An anionic N-heterocyclic olefin ligand was serendipitously obtained by reaction of an amidinate calcium hydride complex with 1,3-dimethyl-2-methyleneimidazole (NHO). Instead of anticipated addition to the polarized C=CH bond to form an unstabilized alkylcalcium complex, deprotonation of the NHO ligand in the backbone was observed. Preference for deprotonation versus addition is explained by loss of aromaticity in the latter conversion. Theoretical calculations demonstrate the substantially increased ylidic character of this anionic NHO ligand which, like N-heterocyclic dicarbenes, shows strong bifunctional coordination.
一种阴离子 N-杂环烯烃配体是通过酰胺基钙氢化物复合物与 1,3-二甲基-2-亚甲基咪唑（NHO）反应意外得到的。在反应中，并未预期酰胺基钙氢化物复合物中的极化 C=CH 键发生加成反应，而是观察到 NHO 配体的去质子化。与加成反应相比，优先发生去质子化反应可以用后者转换过程中芳香性的丧失来解释。理论计算表明，这种阴离子 NHO 配体具有显著增加的叶立德特性，类似于 N-杂环二碳烯，表现出强的双功能配位。
