Controlled Ring-Opening Polymerization of O-Carboxyanhydrides Using a β-Diiminate Zinc Catalyst

Ruibo Wang, Jiawei Zhang, Qian Yin, Yunxiang Xu, Jianjun Cheng, Rong Tong

Research output: Contribution to journalArticlepeer-review

Abstract

Recently O-carboxyanhydrides (OCAs) have emerged as a class of viable monomers which can undergo ring-opening polymerization (ROP) to prepare poly(α-hydroxyalkanoic acid) with functional groups that are typically difficult to achieve by ROP of lactones. Organocatalysts for the ROP of OCAs, such as dimethylaminopyridine (DMAP), may induce undesired epimerization of the α-carbon atom in polyesters resulting in the loss of isotacticity. Herein, we report the use of (BDI-IE)Zn(OCH(CH3)COOCH3) ((BDI)Zn-1, (BDI-IE)=2-((2,6-diethylphenyl)amino)-4-((2,6-diisopropylphenyl)imino)-2-pentene), for the controlled ROP of various OCAs without epimerization. Both homopolymers and block copolymers with controlled molecular weights, narrow molecular weight distributions, and isotactic backbones can be readily synthesized. (BDI)Zn-1 also enables controlled copolymerization of OCAs and lactide, facilitating the synthesis of block copolymers potentially useful for various biomedical applications. Preliminary mechanistic studies suggest that the monomer/dimer equilibrium of the zinc catalyst influences the ROP of OCAs, with the monomeric (BDI)Zn-1 possessing superior catalytic activity for the initiation of ROP in comparison to the dimeric (BDI)Zn complex.

Original languageEnglish (US)
Pages (from-to)13010-13014
Number of pages5
JournalAngewandte Chemie - International Edition
Volume55
Issue number42
DOIs
StatePublished - 2016

Keywords

  • O-carboxyanhydrides
  • copolymerization
  • ring-opening polymerization
  • stereoregularity
  • zinc

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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