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论文类型：期刊论文

发表时间：2013-03-07

发表刊物：POLYMER CHEMISTRY

收录刊物：SCIE、EI、Scopus

卷号：4

期号：5

页面范围：1439-1444

ISSN号：1759-9954

摘要：Mono- and bi-nuclear chromium(III)-salan complexes are efficient catalysts for the alternating copolymerization of terminal epoxides [such as epichlorohydrin (CIPO) and glycidyl phenyl ether (GO)] and cyclic anhydrides [e.g. maleic anhydride (MA) and succinic anhydride (SA)] to afford the corresponding copolymers with >99% ester content. The binuclear complex c bearing a binaphthol linker showed significantly higher activity than the mononuclear chromium-salan complexes a and b. For example, the catalytic activities (based on chromium concentration) of complex c for MA/CIPO and MA/GO copolymerizations are 4.1 and 7.1 times that of complex a, respectively. An intramolecular bimetallic synergistic effect, in which the alternating chain-growth and dissociation of propagating copolymer species take turns at the two metal ions of the binuclear catalyst c, was suggested to make a contribution to the enhanced catalytic activity. Importantly, when using the binuclear complex c as a catalyst for MA/(S)-GO copolymerization, a highly regioregular ring-opening step was observed with a concomitant >99% retention of configuration at the methine carbon center of epoxide incorporated into the polyester.