Di-nuclear zinc complexes containing tridentate imino-benzotriazole phenolate derivatives as efficient catalysts for ring-opening polymerization of cyclic esters and copolymerization of phthalic anhydride with cyclohexene oxide

Chin Hsiang Chang, Hui Ju Chuang, Ting Yi Chen, Chen Yu Li, Chia Her Lin, Ting Yu Lee, Bao Tsan Ko*, Hsi Ya Huang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Zinc catalysts incorporated by imino-benzotriazole phenolate (IBTP) ligands were synthesized and characterized by single-crystal X-ray structure determinations. The reaction of the ligand precursor (C1DMeIBTP-H or C1DIPIBTP-H) with diethyl zinc (ZnEt2) in a stoichiometric proportion in toluene furnished the di-nuclear ethyl zinc complexes [(μ-C1DMeIBTP)ZnEt]2 (1) and [(μ-C1DIPIBTP)ZnEt]2 (2). The tetra-coordinated monomeric zinc complex [(C1PhIBTP)2Zn] (3) or [(C1BnIBTP)2Zn] (4) resulted from treatment of C1PhIBTP-H or C1BnIBTP-H as the pro-ligand under the similar synthetic method with ligand to metal precursor ratio of 2:1. Single-crystal X-ray diffraction of bimetallic complexes 1 and 2 indicates that the C1DMeIBTP or C1DIPIBTP fragment behaves a NON-tridentate ligand to coordinate two metal atoms. Catalysis for ring-opening polymerization (ROP) of ε-caprolactone (ε-CL), β-butyrolactone (β-BL), and lactide (LA) of complexes 1 and 2 was systematic studied. In combination with 9-anthracenemethanol (9-AnOH), Zn complex 1 was found to polymerize ε-CL, β-BL, and L-LA with efficient catalytic activities in a controlled character. This study also compared the reactivity of these ROP monomers with different ring strains by Zn catalyst 1 in the presence of 9-AnOH. Additionally, Zn complex 1 combining with benzoic acid was demonstrated to be an active catalytic system to copolymerize phthalic anhydride and cyclohexene oxide.

Original languageEnglish
Pages (from-to)714-725
Number of pages12
JournalJournal of Polymer Science, Part A: Polymer Chemistry
Volume54
Issue number5
DOIs
Publication statusPublished - 2016 Mar 1
Externally publishedYes

Keywords

  • catalysis
  • cyclic esters
  • imino-benzotriazole phenolate ligands
  • ring-opening polymerization (ROP)
  • zinc

ASJC Scopus subject areas

  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry

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