Highly Active and Robust Metalloporphyrin Catalysts for the Synthesis of Cyclic Carbonates from a Broad Range of Epoxides and Carbon Dioxide

Chihiro Maeda, Junta Shimonishi, Ray Miyazaki, Jun ya Hasegawa, Tadashi Ema

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88 Citations (Scopus)

Abstract

Bifunctional metalloporphyrins with quaternary ammonium bromides (nucleophiles) at the meta, para, or ortho positions of meso-phenyl groups were synthesized as catalysts for the formation of cyclic carbonates from epoxides and carbon dioxide under solvent-free conditions. The meta-substituted catalysts exhibited high catalytic performance, whereas the para- and ortho-substituted catalysts showed moderate and low activity, respectively. DFT calculations revealed the origin of the advantage of the meta-substituted catalyst, which could use the flexible quaternary ammonium cation at the meta position to stabilize various anionic species generated during catalysis. A zinc(II) porphyrin with eight nucleophiles at the meta positions showed very high catalytic activity (turnover number (TON)=240000 at 120°C, turnover frequency (TOF)=31500h-1 at 170°C) at an initial CO2 pressure of 1.7MPa; catalyzed the reaction even at atmospheric CO2 pressure (balloon) at ambient temperature (20°C); and was applicable to a broad range of substrates, including terminal and internal epoxides.

Original languageEnglish
JournalChemistry - A European Journal
DOIs
Publication statusAccepted/In press - 2016

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Keywords

  • Carbon dioxide fixation
  • Cyclic carbonates
  • Epoxides
  • Homogeneous catalysts
  • Porphyrinoids

ASJC Scopus subject areas

  • Chemistry(all)

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