Sonogashira Coupling Reaction Mediated By Modified MOFs Materials

Sonogashira coupling reaction,a famous carbon-carbon bond forming reaction,has been widely applied in the synthesis of pharmaceuticals and complicated organic compounds.The catalyst of homogeneous Sonogashira coupling reaction suffers from its isolation and recycling.Thus,heterogeneous catalysts,especially Pd-based heterogeneous catalysts have been attracted much attention recently.However,aggregation and loss of active components inhibit their application.Thus,it is of great significance to construct a stable heterogeneous catalyst on an alkaline support with high specific surface area.MOFs is a new class of hybrid porous material with high surface areas,great porosity,tunable cavity,and easy functionalization,which shows attractive prospects in gas adsorption and separation,catalysis,magnetism,and.medicine.Recently,Mn-MIL-100 and ZIF-8 receive considerable attentions because of the coordinatively unsaturated sites and the chemical/thermal stability,respectively.ZIF-8 has a potential to be a good support ascribed to alkaline imidazole ligands.Based on the nature of MOFs and modified MOFs materials,they were applied in the sonogashira coupling reaction of iodobenzene and phenylacetylene.The detailed information is provided as following:1.Mn-MIL-100 was successfully prepared by hydrothermal method and employed to catalyse the above Sonogashira coupling reaction.It was found that poor yield coupling products（less than 35%）were occasionally detected when the sonogashira coupling reaction of iodobenzene and phenylacetylene proceeded only over Mn-MIL-100.2.A series of MOFs,such as Al-based,Fe-based and Zn-based,were prepared.The characterization results indicated that ZIF-8 is the suitable alkaline support.Monometallic Pd@ZIF-8,Ni@ZIF-8 and bimetallic Pd_xNi?_y@ZIF-8 catalysts were synthesized by a simple liquid impregnation-reduction method.Their catalytic performances were evaluated by Sonogashira coupling reaction,it was found that 3 wt%Pd₅Ni₉₅@ZIF-8 exhibited the excellent catalytic performance for the above reaction with 91.75%yield.Moreover,it shows nice catalytic behavior in variaty of Sonogashira coupling reactions and satisfied recycling stability.3.The catalytic performance of Pd@ZIF-8,Ni@ZIF-8 and Pd₅Ni₉₅@ZIF-8 in the sonogashira coupling reaction of iodobenzene and phenylacetylene was compared.The obtained results,combined with their characterization results demonstrated the synergistic effect between Pd and Ni of Pd₅Ni₉₅@ZIF-8,trace of Pd can enhance the catalytic activity of Ni@ZIF-8 dramatically.