Efficient Polymerization\nand Selective Depolymerization\nof Poly(cyclopentene carbonate) Mediated Solely by Heterometallic\nRare-Earth(III)/Zinc(II) Complexes

Poly(cyclopentenyl\ncarbonate) (PCPC) is a recyclable\npolymer with\ngreat potential applications. However, the selective preparation of\nPCPC from cyclopentene oxide (CPO) and CO<sub>2</sub> copolymerization\nand the chemical recycling of PCPC back to the original monomer CPO\nare of great challenge. In this work, it was found that the heterometallic\nrare-earth metal(III)/Zn(II) complexes (RE(III)-Zn(II) complexes)\nsupported by phenylenediamine-bridged triphenols could serve as highly\nactive catalysts for the copolymerization of CPO and CO<sub>2</sub> to give pure PCPC. Remarkably, the same complexes alone could also\npromote the selective depolymerization of PCPC to CPO only by simply\nraising the reaction temperature up to ca. 160 °C. The copolymerization\nand depolymerization mechanisms were also proposed.