N-donor-stabilized Pd(II) species supported by sulphonamide-azo ligands: Ligand architecture, solvent co-ligands, C–C coupling
作者:Hammed Olawale Oloyede、Joseph Anthony Orighomisan Woods、Helmar Görls、Winfried Plass、Abiodun Omokehinde Eseola
DOI:10.1016/j.molstruc.2019.127030
日期:2020.1
were prepared and examined as organic ligands for stabilizing palladium active centers; R = methyl, tolyl or triiso-propylphenyl. Palladium complexes, which were obtained in varying coordination environments as well as with varying complementary co-ligands (water, acetonitrile or pyridine), have been subjected to Suzuki and Heck coupling experiments in order to study molecular level ligand effects on
摘要 在本报告中,制备了一系列合成价格合理的无膦配体(L1-L4),形式为 RSO2-NH-Ph-NN-Ph-NH-SO2R,作为稳定钯活性中心的有机配体;R = 甲基、甲苯基或三异丙基苯基。在不同的配位环境以及不同的互补共配体(水、乙腈或吡啶)中获得的钯配合物已进行 Suzuki 和 Heck 偶联实验,以研究分子水平配体对优选催化剂设置的影响。由螯合配体产生的钯物种记录了 Suzuki 和 Heck 与官能团耐受性偶联的显着偶联活性。结果表明,尽管这些偶氮苯配体具有三齿螯合特性,在磺酰基上引入大单元使得能够产生具有高周转频率的活性钯物种;例如,在 5 分钟内以 0.2 mol % Pd.L2.py 负载量在仅作为溶剂的水中进行 5040 h-1(84% 产率)。获得了催化效率与配位共配体的体积之间的相关性。然而,虽然 Suzuki 偶联活性随着预形成复合物(即水