Palladium catalyzed Suzuki C–C couplings in an ionic liquid: nanoparticles responsible for the catalytic activity
作者:Fernando Fernández、Beatriz Cordero、Jérôme Durand、Guillermo Muller、François Malbosc、Yolande Kihn、Emmanuelle Teuma、Montserrat Gómez
DOI:10.1039/b713449e
日期:——
A new family of functionalized ligands derived from norborn-5-ene-2,3-dicarboxylic anhydride has been used in Suzuki CâC cross-couplings between aryl boronic acids and aryl bromide derivatives in [BMI][PF6] (BMI = 1-n-butyl-3-methyl-imidazolium), using palladium acetate as catalytic precursor. High conversions and yields are obtained when amine ligands containing hydroxy groups are involved. TEM analyses after catalysis show the formation of small nanoparticles, in contrast to the agglomerates observed when nanoparticles are intentionally preformed, with a consequent decrease in the catalytic activity in the latter case. Some tests, including the correlation effect between solvent and ligand, are carried out to try to identify the true nature of the catalyst. All the results obtained suggest that formation of nanoparticles is required to lead to a catalytically active system.
一种新型的功能化配体家族,来源于诺尔本-5-烯-2,3-二羧酸酐,已被用于[具阴离子PF6的1-丁基-3-甲基咪唑盐(BMI)]中芳基硼酸与芳基溴化物衍生物的铃木C–C交叉偶联反应,使用醋酸钯作为催化前驱体。当涉及含羟基的胺配体时,获得了高转化率和高产率。催化后进行的透射电子显微镜(TEM)分析显示形成了小纳米粒子,这与故意预制纳米粒子时观察到的聚集体形成对比,在后者情况下催化活性明显降低。进行了一些测试,包括溶剂与配体之间的相关性,以尝试确定催化剂的真实特性。所有获得的结果都表明,纳米粒子的形成是实现催化活性系统所必需的。