Cobalt?Mediated Switchable Catalysis for the One?Pot Synthesis of Cyclic Polymers
نویسندگان
چکیده
A cobalt salen pentenoate complex [salen=(R,R)-N,N?-bis(3,5-di-tertbutylsalicylidene)-1,2-cyclohexanediamine] is rationally designed as the catalyst for ring-opening copolymerization (ROCOP) of epoxides/anhydrides/CO2. Via migratory insertion carbon monoxide (CO) into Co?O bonds, ROCOP-active species ?-alkene-?-O-CoIII(salen) can be rapidly and quantitatively transformed ?-alkene-?-O2C-CoIII(salen) telechelic linear precursors. Upon dilution reaction mixtures, homolytic cleavage Co?C bonds induced by visible light generates ?-alkene acyl radicals that spontaneously undergo intramolecular radical addition to afford organocobalt-functionalized cyclic polyesters CO2-based polycarbonates with excellent regioselectivity. The products either react scavengers generate metal-free polymers or serve photo-initiators organometallic-mediated polymerization (OMRP) produce tadpole-shaped copolymers.
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ژورنال
عنوان ژورنال: Angewandte Chemie
سال: 2021
ISSN: ['1521-3773', '1433-7851', '0570-0833']
DOI: https://doi.org/10.1002/anie.202106285