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Zwitterionic Design Principle of Nickel(II) Catalysts for Carbonylative Polymerization of Cyclic Ethers
Author(s) -
Dai Yiwei,
He Shiyu,
Peng Bangan,
Crandall Laura A.,
Schrage Briana R.,
Ziegler Christopher J.,
Jia Li
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201808507
Subject(s) - oxonium ion , chemistry , nucleophile , cationic polymerization , polymer chemistry , tetrahydrofuran , ether , catalysis , electrophile , vinyl ether , polymerization , ethylene oxide , monomer , organic chemistry , copolymer , ion , polymer , solvent
Zwitterionic structure is necessary for Ni II complexes to catalyze carbonylative polymerization (COP) of cyclic ethers. The cationic charge at the Ni II 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 0 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.