Calcium Hydride Reactivity: Formation of an Anionic N-Heterocyclic Olefin Ligand
Calcium Hydride Reactivity: Formation of an Anionic N-Heterocyclic Olefin Ligand
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DOI：
10.1002/anie.201703037
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发表时间：
2017-06-06
影响因子：
16.6
通讯作者：
Harder, Sjoerd
中科院分区：
文献类型：
--
作者：
Causero, Andrea;Elsen, Holger;Harder, Sjoerd
通过脒基氢化钙配合物与1，3-二甲基-2-亚甲基咪唑（NHO）反应，意外地得到了一种阴离子N-杂环烯烃配体。观察到骨架中NHO配体的去质子化，而不是预期的添加到极化的C= CH 2键中形成不稳定的烷基钙复合物。对去质子化与加成的偏好是由后者转化中芳香性的损失来解释的。理论计算表明，这种阴离子NHO配体，像N-杂环二卡宾，表现出很强的双功能协调的叶立德字符大幅增加。
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=CH2 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.