氮杂环卡宾-钯绿色、高效配合物的设计、合成及其构效关系研究

In view of traditional amination reactions using air-sensitive, toxic and expensive tertiary phosphine-palladium complexes and recently a few reports using N-heterocyclic carbene-palladium complexes possessing the disadvantages of lengthy synthetic routes or lower catalytic efficiency, in this project, we aim to design and synthesis a series of electron-rich and sterically-hindered N-heterocyclic carbene ligands, and screen some N-containing ancillary ligands. In addition, on the basis of the coordination polyhedron structure and the rules of ligand substitution, we will seek a new route for the synthesis of green, stable and highly efficient N-heterocyclic carbene-palladium complexes. After the structure of the N-heterocyclic carbene-palladium complexes were characterized by NMR, mass spectroscopy, elemental analysis and X-ray single crystal diffraction, their catalytic activity will be evaluated in the coupling reaction of chlorobenzene with aniline. Based on these results and combining the analysis on the structure-activity relationship, a more reasonable mechanism will be given. The above results will not only give optimized route for the synthesis of N-heterocyclic carbene-palladium complexes with high catalytic activity and will also enrich the theory of their catalysis. Furthermore, it will aslo give stable catalysts for the green and efficeint synthetic process.

针对传统胺化反应采用对空气敏感、有毒、价格昂贵的叔膦-钯配合物体系及最近少量报导的氮杂环卡宾-钯配合物催化剂合成步骤复杂或催化效率不高等难点、热点问题，本项目拟设计、合成系列富电子、大位阻氮杂环卡宾配体，筛选含氮辅助配体，依据配位多面体结构及配位取代反应规律，探寻组装稳定、绿色、高效氮杂环卡宾-钯配合物的简便新途径。采用核磁共振、质谱、元素分析及X-ray单晶衍射等方法进行结构表征后，再结合目标配合物在氯苯与苯胺的偶联反应中的催化效率及量化模拟，进行结构与功能的相关性分析，提出与实验结果一致的更合理的催化机理。以上成果不仅优化了高催化活性氮杂环卡宾-钯配合物的合成路线，提高了其催化效率，丰富了其催化作用的理论基础，而且也将为绿色、高效的合成工艺提供稳定的催化剂。

针对传统胺化反应采用对空气敏感、有毒、价格昂贵的叔膦-钯配合物体系及最近报导的氮杂环卡宾-钯配合物催化剂合成步骤复杂或催化效率不高等问题，本项目通过筛选不同的含氮辅助配体，通过一步简洁的操作，顺利合成了一系列高催化活性的氮杂环卡宾-钯配合物，所有配合物均对水汽、空气和热稳定，能在室温条件下自由保存。在价廉、易得的芳基氯化物参与的偶联反应中，催化效率相当高效。特别需要指出的是，在芳基氯化物参与的胺化反应中，最低催化量达0.005 mol%。这些氮杂环卡宾-钯配合物还能高效地催化二氯苯类化合物的单一Suzuki-Miyaura偶联反应、酮的alfa-芳基化反应。此外，使用本课题组前期发展的氮杂环卡宾-钯(II)-1-甲基咪唑配合物为催化剂，高效地实现了烯丙醇、苄基磺酸酯和苄基二甲胺基碳酸酯与芳基硼酸的偶联。本项目的实施，优化了高催化活性氮杂环卡宾-钯配合物的合成路线，提高了催化效率，为绿色、高效的合成工艺提供稳定的催化剂。