Analyses of the Structural and Electronic Properties of NHCs with Bicyclic Architectures
Analyses of the Structural and Electronic Properties of NHCs with Bicyclic Architectures
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双环结构 NHC 的结构和电子特性分析
DOI：
10.1021/acs.organomet.0c00564
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发表时间：
2020
期刊：
影响因子：
2.8
通讯作者：
Ishizuka Tadao
中科院分区：
文献类型：
--
作者：
Ando Shin;Otsuka Mio;Ishizuka Tadao
当使用金属配合物作为催化剂时，配体的空间和电子性质的量化是开发高效化学转化的重要任务。在这项研究中，我们使用银和铱配合物进行系统分析，量化了原始NHCs的空间和电子性质，我们称之为DHASI和BCPSI。除了我们之前报道的两种氯化银配合物外，还制备了两种新型的BCPSIiPrAgCl和BCPSICyAgCl配合物，并通过使用称为埋藏体积百分比（%VBur）的方法进行XRD研究，以量化其空间结构性质。然后我们合成了6个IrCl(CO)2（HNC）配合物来计算TEP值，结果表明两种不同核心双环基序的影响不太清楚，而不同n取代基的影响很明显。最后，将原始NHCs应用于铜催化肉桂基溴与PhMgBr的烯丙基芳基化反应。取代的区域选择性表明，距离结合铜相对较远的空间环境对催化性能也有相当大的影响。
Quantification of the steric and electronic properties of ligands is an important task for the development of highly effective chemical transformations when using a metal complex as a catalyst. In this study, we used silver and iridium complexes to perform systematic analyses to quantify the steric and electronic properties of original NHCs, which we refer to as DHASI and BCPSI. In addition to two silver chloride complexes that we previously reported, two novel BCPSIiPrAgCl and BCPSICyAgCl complexes were prepared and used for XRD studies to quantify the steric properties via use of a method referred to as the percent buried volume (%VBur). We then synthesized 6 IrCl(CO)2(HNC) complexes to calculate the TEP values, and the results indicated that the influences of two different core bicyclic motifs were somewhat unclear, while the influences of different N-substituents were readily apparent. Finally, the original NHCs were applied to a copper catalyzed allylic arylation of cinnamyl bromide with PhMgBr. The regioselectivity of the substitutions suggested that the steric environments existing at relatively long distances from the bound copper also exerted a considerable amount of influence over the catalytic properties.