Activation Mechanism of Nickel(0) N -Heterocyclic Carbene Catalysts Stabilized by Fumarate Ligands
Activation Mechanism of Nickel(0) N -Heterocyclic Carbene Catalysts Stabilized by Fumarate Ligands
复制标题
富马酸配体稳定镍(0)N-杂环卡宾催化剂的活化机理
DOI：
10.1021/acs.organomet.2c00279
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发表时间：
2022
期刊：
影响因子：
2.8
通讯作者：
Montgomery, John
中科院分区：
文献类型：
--
作者：
Robo, Michael T.;Frank, Amie R.;Butler, Ellen;Nett, Alex J.;Cañellas, Santiago;Zimmerman, Paul M.;Montgomery, John
以缺电子烯烃为稳定剂的N-杂环卡宾镍催化剂具有良好的耐空气性和易操作性，同时保持了较高的催化活性。由于催化剂的稳定性往往以牺牲催化活性为代价，我们已经进行了详细的研究，由富马酸二（邻甲苯基）酯稳定的IMes-镍（0）催化剂的活化机制，将稳定的预催化剂形式转化为催化活性物质。计算评估提供了证据，对一个简单的配体交换作为这种催化剂的活化机制，和化学计量活化过程，共价修饰的稳定配体被确定。开发了活化过程的详细计算图，具有预测性见解，阐明了当配体交换在物理上不利时操作的意想不到的催化剂活化途径。
Nickel(0) catalysts ofN-heterocyclic carbenes (NHCs) that are stabilized by electron-deficient alkenes possess desirable properties of air tolerance and ease of handling while also retaining high catalytic activities. Since catalyst stability often comes at the expense of catalytic activity, we have undertaken a detailed study of the activation mechanism of an IMes-nickel(0) catalyst stabilized by di(o-tolyl) fumarate that converts the stable precatalyst form into a catalytically active species. Computational evaluation provided evidence against a simple ligand exchange as the activation mechanism for this catalyst, and a stoichiometric activation process that covalently modifies the stabilizing ligand was identified. A detailed computational picture for the activation process was developed, with predictive insights that elucidate an unexpected catalyst activation pathway that operates when ligand exchange is thermodynamically unfavorable.