Phenanthroline functionalized polyacrylonitrile fiber with Pd(0) nanoparticles as a highly active catalyst for the Heck reaction

A series of polyacrylonitrile fibers (PANF) functionalized with nitrogen-containing ligands were prepared and then used to synthesize fiber-supported Pd(0) nanoparticle catalysts. The phenanthroline-functionalized PANF with immobilized Pd(0) nanoparticles (PANPhenF-Pd(0)) had the best catalytic activity for the Heck reaction under solvent-free conditions. The PANPhenF-Pd(0) efficiently stabilized the nanoparticles and they were welldispersed with Pd(0) particle sizes of about 3 nm. The PANPhenF-Pd(0) structure was further characterized by a variety of instrumental methods. A probable mechanism based on the fiber?s microenvironment is proposed for the Heck reaction catalyzed by PANPhenF-Pd(0). The PANPhenF-Pd(0) catalyst is easily recovered from the reaction system and can be used up to six times with only a slight decrease in catalytic activity and with low Pd leaching. The PANPhenF-Pd(0) catalyst also has excellent catalytic activity for gram-scale use.