A new G-(H2L)-Pd heterogeneous catalyst has been prepared via a self-assembly process consisting in the spontaneous adsorption, in water at room temperature, of a macrocyclic H2L ligand on graphene (G) (G + H2L = G-(H2L)), followed by decoration of the macrocycle with Pd2+ ions (G-(H2L) + Pd2+ = G-(H2L)-Pd) under the same mild conditions. This supramolecular approach is a sustainable (green) procedure that preserves the special characteristics of graphene and furnishes an efficient catalyst for the Cu-free Sonogashira cross coupling reaction between iodobenzene and phenylacetylene. Indeed, G-(H2L)-Pd shows an excellent conversion (90%) of reactants into diphenylacetylene under mild conditions (50 °C, water, aerobic atmosphere, 14 h). The catalyst proved to be reusable for at least four cycles, although decreasing yields down to 50% were observed.
通过自组装过程,制备了一种新的G-(H2L)-Pd异质催化剂,该过程包括在室温下,在水中自发吸附大环H2L配体于石墨烯(G)上(G + H2L = G-(H2L)),然后在相同温和条件下用Pd2+离子装饰大环(G-(H2L) + Pd2+ = G-(H2L)-Pd)。这种超分子方法是一种可持续(绿色)的程序,保留了石墨烯的特殊特性,并为无铜Sonogashira交叉偶联反应提供了高效的催化剂,反应为碘苯和苯乙炔之间的反应。实际上,G-(H2L)-Pd在温和条件下(50℃,水,空气氛围,14小时)显示出优异的转化率(90%)。尽管观察到逐渐降低的收率(降至50%),但该催化剂可重复使用至少四个周期。