Immobilization of Molecular Catalysts on Silica via New Tripodal Linker Unit

The design and synthesis of a new linker unit to enable uniform and robust immobilization of organic functional molecules onto silica supports is described. This linker unit can prevent leaching of grafted organic functional moieties from the support. The tripodal linker unit was applied to the preparation of mesoporous silica-immobilized amino-palladium and phosphino-palladium complex catalysts for the Suzuki-Miyaura coupling reaction of aryl bromides and aryl chlorides. Catalysts including the tripodal linker displayed better catalytic activities and less palladium leaching than catalysts including a conventional trialkoxy-type linker.