Ultra‐small metal nanoclusters have high surface energy and abundant active sites,and thereforetheir catalytic activities are usually significantly higher than those of larger nanoparticles.A temperature‐responsive ...Ultra‐small metal nanoclusters have high surface energy and abundant active sites,and thereforetheir catalytic activities are usually significantly higher than those of larger nanoparticles.A temperature‐responsive copolymer,namely poly(ethylene glycol)‐co‐poly(N‐isopropylacrylamide)(PEG‐PNIPAM)was synthesized as the first step,and then ultra‐small Pd clusters stabilized withinPEG‐PNIPAM copolymer micelles were formed by direct reduction.Pd nanoclusters of size less than2nm showed outstanding catalytic activity in the Suzuki coupling reaction.The reaction betweeniodobenzene and phenylboronic acid was completed in as little as10s(turnover frequency=4.3×104h?1).A yield of64%was achieved in5min in the reaction between chlorobenzene and phenylboronicacid.The catalyst showed significant deactivation during three consecutive runs.However,this composite catalyst consisting of Pd/PEG‐PNIPAM can be easily recycled based on the reversiblephase transition of temperature‐responsive PEG‐PNIPAM.This catalyst therefore has good potentialfor practical applications.展开更多
基金supported by the National Natural Science Foundation of China (51502089,51302008)the Fundamental Research Funds for the Central Universities (2016MS03)~~
文摘Ultra‐small metal nanoclusters have high surface energy and abundant active sites,and thereforetheir catalytic activities are usually significantly higher than those of larger nanoparticles.A temperature‐responsive copolymer,namely poly(ethylene glycol)‐co‐poly(N‐isopropylacrylamide)(PEG‐PNIPAM)was synthesized as the first step,and then ultra‐small Pd clusters stabilized withinPEG‐PNIPAM copolymer micelles were formed by direct reduction.Pd nanoclusters of size less than2nm showed outstanding catalytic activity in the Suzuki coupling reaction.The reaction betweeniodobenzene and phenylboronic acid was completed in as little as10s(turnover frequency=4.3×104h?1).A yield of64%was achieved in5min in the reaction between chlorobenzene and phenylboronicacid.The catalyst showed significant deactivation during three consecutive runs.However,this composite catalyst consisting of Pd/PEG‐PNIPAM can be easily recycled based on the reversiblephase transition of temperature‐responsive PEG‐PNIPAM.This catalyst therefore has good potentialfor practical applications.
