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Alternating copolymerization of CO_(2) and cyclohexene oxide initiated by rare-earth metal complexes stabilized by o-phenylenediamine-bridged tris(phenolate)ligand 被引量:2
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作者 quanyou yao Yongjie Chen +3 位作者 yaorong Wang Dan Yuan Hongpeng You Yingming yao 《Journal of Rare Earths》 SCIE EI CAS CSCD 2022年第9期1471-1479,I0005,共10页
A series of o-phenylenediamine bridged tris(phenolate)ligand-stabilized rare-earth metal complexes were synthesized and characterized.Lanthanum(complex 1),neodymium(complex 2^(tBu)),and yttrium(complex 3)complexes sta... A series of o-phenylenediamine bridged tris(phenolate)ligand-stabilized rare-earth metal complexes were synthesized and characterized.Lanthanum(complex 1),neodymium(complex 2^(tBu)),and yttrium(complex 3)complexes stabilized by ligand of buiky tert-butyl substituents are mononuclear,whereas neodymium complexes 2^(Me)and 2^(C1)bearing smaller methyl and chloro substituents are dinuclear,respectively.They were applied in the alternating copolymerization of CO_(2)and cyclohexene oxide.The addition of benzyl alcohol is beneficial to improving yields(up to 86%)and selectivity of poly(carbonate)(up to 99%).Stoichiometric reaction of benzyl alcohol with rare-earth metal complexes 1 and 2^(tBu)results in formation of complexes 4 and 5 as dinuclear complexes with benzyl alcohol coordination,which was confirmed via single crystal X-ray diffraction analysis,and nuclear magnetic resonance(NMR)spectroscopy(for 4).Complex 5 shows equally good activity and selectivity of that of complex 2^(tBu)and benzyl alcohol,consolidating that complex 5 is indeed generated during polymerization.The neodymium tris(phenolate)5 is one of the few examples of rare-earth metal complex as a single-component initiator for copolymerization of epoxide and CO_(2).Matrix-assisted laser desorption ionization-time of flight(MALDI-TOF)mass spectrometry analysis proves benzyloxy group as the chain end.^(1)H NMR monitoring suggests that the insertion of CO_(2)may be the first step in the growth of the polymer chain. 展开更多
关键词 Rare earths CO_(2) COPOLYMERIZATION Polycarbonate Single-component initiator
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