Palladium Complexes with Pyrimidine-Functionalized N-Heterocyclic Carbene Ligands: Synthesis, Structure and Catalytic Activity
Palladium Complexes with Pyrimidine-Functionalized N-Heterocyclic Carbene Ligands: Synthesis, Structure and Catalytic Activity
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DOI：
10.1021/om8009238
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发表时间：
2009-03
期刊：
影响因子：
2.8
通讯作者：
D. Meyer;M. Taige;A. Zeller;Konrad Hohlfeld;S. Ahrens;T. Strassner
中科院分区：
文献类型：
--
作者：
D. Meyer;M. Taige;A. Zeller;Konrad Hohlfeld;S. Ahrens;T. Strassner
以相应的银配合物为原料，采用金属转金属法合成了一系列具有芳基和烷基取代基的新型嘧啶功能化钯（II）（NHC）配合物[1-（2-嘧啶基）-3-（芳基或烷基）咪唑啉-2-酰基钯（II）氯化物]。所有化合物都通过1H和13C核磁共振光谱，元素分析和两个案例的x射线单晶结构进行了充分的表征。芳基和烷基取代配体的固体结构不同：对于空间要求较低的甲基取代基，形成一个配合物，其中两个配体配位到一个金属中心[Pd(L)2Cl]+，而在甲酰基情况下，观察到一个[Pd(L)Cl2]结构。它们在甲烷的CH活化和Mizoroki-Heck反应中表现出良好的催化活性，特别是甲基取代配合物表现出非常高的活性和非常高的选择性。
A series of novel pyrimidine functionalized palladium(II)(NHC) complexes with aryl and alkyl substituents [1-(2-Pyrimidyl)-3-(aryl or alkyl)imidazoline-2-ylidene palladium(II) chlorides] was synthesized by transmetalation via the corresponding silver complexes. All compounds have been fully characterized by 1H and 13C NMR spectroscopy, elemental analysis, and in two cases by X-ray single crystal structures. Different solid state structures were observed for aryl and alkyl substituted ligands: for the sterically less demanding methyl substituent, a complex is formed, where two ligands are coordinated to one metal center [Pd(L)2Cl]+, while in the mesityl case a [Pd(L)Cl2] structure was observed. They show good catalytic activity in the CH activation of methane as well as in the Mizoroki-Heck reaction, where especially the methyl substituted complex shows a remarkably high activity combined with a very high selectivity.