National Changhua University of Education Institutional Repository : Item 987654321/10077
English  |  正體中文  |  简体中文  |  全文筆數/總筆數 : 6507/11669
造訪人次 : 29714520      線上人數 : 378
RC Version 3.2 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
搜尋範圍 進階搜尋

請使用永久網址來引用或連結此文件: http://ir.ncue.edu.tw/ir/handle/987654321/10077

題名: A New Tridentate Pincer Phosphine/N-Heterocyclic Carbene Ligand: Palladium Complexes, their Structures, and Catalytic Activities
作者: Lee, H. M.;Zeng, J. Y.;Hu, Ching-Han;Lee, M. T.
貢獻者: 化學系
日期: 2004-10
上傳時間: 2012-05-03T06:17:50Z
出版者: American Chemical Society
摘要: A new imidazolium salt, 1,3-bis(2-diphenylphosphanylethyl)-3H-imidazol-1-ium chloride (2), for the phosphine/N-heterocyclic carbene-based pincer ligand, PCNHCP, and its palladium complexes were reported. The complex, [Pd(PCNHCP)Cl]Cl (4), was prepared by the common route of silver carbene transfer reaction and a novel direct reaction between the ligand precursor, PCNHCP·HCl and PdCl2 without the need of a base. Metathesis reactions of 4 with AgBF4 in acetonitrile produced [Pd(PCNHCP)(CH3CN)](BF4)2 (5). The same reaction in the presence of excess pyridine gave [Pd(PCNHCP)(py)](BF4)2 (6). The X-ray structure determination on 4−6 revealed the chiral twisting of the central imidazole rings from the metal coordination plane. In solution, fast interconversion between left- and right-twisted forms occurs. The twisting reflects the weak π-accepting property of the central NHC in PCNHCP. The uneven extent of twisting among the three complexes further implies the low rotational barrier about the Pd−NHC bond. Related theoretical computations confirm the small rotational energy barrier about the Pd−NHC bond (ca. 4 kcal/mol). Catalytic applications of 4 and 5 have shown that the complexes are modest catalysts in Suzuki coupling. The complexes were active catalysts in Heck coupling reactions with the dicationic complex 5 being more effective than the monocationic complex 4.
關聯: Inorg. Chem., 43(21): 6822-6829
顯示於類別:[化學系] 期刊論文

文件中的檔案:

檔案 大小格式瀏覽次數
index.html0KbHTML1031檢視/開啟


在NCUEIR中所有的資料項目都受到原著作權保護.

 


DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - 回饋