Dai Yiwei, He Shiyu, Peng Bangan, Crandall Laura A, Schrage Briana R, Ziegler Christopher J, Jia Li
Department of Polymer Science, The University of Akron, Akron, OH, 44325-3909, USA.
Department of Chemistry, The University of Akron, Akron, OH, 44325, USA.
Angew Chem Int Ed Engl. 2018 Oct 22;57(43):14111-14115. doi: 10.1002/anie.201808507. Epub 2018 Oct 2.
Zwitterionic structure is necessary for Ni complexes to catalyze carbonylative polymerization (COP) of cyclic ethers. The cationic charge at the Ni center imparts sufficient electrophilicity to the Ni-acyl bond for it to react with cyclic ethers to give an acyl-cyclic ether oxonium intermediate, while the ligand-centered anionic charge ensures that the resultant oxonium cation is ion-paired with the Ni nucleophile. The current catalysts give non-alternating copolymers of carbon monoxide and cyclic ethers and are the most effective when both ethylene oxide and tetrahydrofuran are present as the cyclic ether monomers.
