Selenium-Containing N-Heterocyclic Carbenes and Their First Palladium(II) Complexes: Synthesis, Structure, and Pendent Alkyl Chain Length Dependent Catalytic Activity for Suzuki–Miyaura Coupling
作者:Kamal Nayan Sharma、Hemant Joshi、Alpesh K. Sharma、Om Prakash、Ajai K. Singh
DOI:10.1021/om400148c
日期:2013.4.22
Pd and Se. The Pd:Se is nearly 3:2, 4:5, and 1:1 in NPs formed from 1, 2, and 3, respectively. The catalytic activity of 3, having the longest alkyl chain containing (Se CNHC) ligand among the three complexes, has been found to be higher relative to those of 1 and 2. The length of the alkyl chain present in the complex molecule probably controls the catalytic activity by influencing the dispersion of
三个新的N-烷基-N '-(2-乙基-1-硒代苯基)咪唑鎓盐L1 - L3(N的烷基取代基的链长不同),它们是(Se,C NHC)配体的前体N-杂环卡宾(NHC)络合物[钯(L- HX)氯2 ](1 - 3)[大号= L1 - L3,X = I / BR],已经合成和表征通过多核NMR和HR-MS。为Pd所构成的复合物的合成1 - 3从适当咪唑盐(L1 - L3),已采用银卡宾转移反应的途径。已经通过X射线衍射建立了1和2的单晶结构。热稳定的,水分和空气不敏感的复合物1 - 3已被发现可用于铃木-宫浦偶联反应(产率高达96%在2小时内,在80℃C)的有效催化剂。在这些反应开始时(即,当反应混合物的温度达到80°C时)形成的纳米颗粒(NPs)(大小为80–85%的颗粒〜2–5 nm)似乎对催化偶联很重要,可能是因为Pd(0)的分配器,并包含Pd和Se。将Pd:硒是近3:2,4:5和1:1中,从形成的NP