TY - JOUR
T1 - Highly Active and Robust Metalloporphyrin Catalysts for the Synthesis of Cyclic Carbonates from a Broad Range of Epoxides and Carbon Dioxide
AU - Maeda, Chihiro
AU - Shimonishi, Junta
AU - Miyazaki, Ray
AU - Hasegawa, Jun Ya
AU - Ema, Tadashi
N1 - Funding Information:
This work was supported by the ENEOS Hydrogen Trust Fund, Okayama Foundation for Science and Technology, and the Ministry of Education, Culture, Sports, Science and Technology (MEXT) in Japan. The work at Hokkaido University was supported by JSPS KAKENHI Grant Number 15H05805 and the FLAGSHIP2020(priority study 5) program from MEXT. NMR spectra were obtained at the SC-NMR Laboratory ofOkayama University. Computations were partly carried out at RCCS (Okazaki, Japan) and ACCMS (Kyoto University). We thank Prof. A. Osuka (Kyoto University) for MS measurements.
Publisher Copyright:
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
PY - 2016/5/4
Y1 - 2016/5/4
N2 - 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)=240 000 at 120 °C, turnover frequency (TOF)=31 500h-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. In a fix! Bifunctional metalloporphyrins act as catalysts for the formation of cyclic carbonates from epoxides and CO2 (see scheme). A comparison of the catalytic activities shows the superior performance of meta-substituted catalysts. A robust zinc(II) porphyrin with eight nucleophiles at the meta positions shows the highest catalytic activity and a broad substrate scope, including terminal and internal epoxides.
AB - 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)=240 000 at 120 °C, turnover frequency (TOF)=31 500h-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. In a fix! Bifunctional metalloporphyrins act as catalysts for the formation of cyclic carbonates from epoxides and CO2 (see scheme). A comparison of the catalytic activities shows the superior performance of meta-substituted catalysts. A robust zinc(II) porphyrin with eight nucleophiles at the meta positions shows the highest catalytic activity and a broad substrate scope, including terminal and internal epoxides.
KW - carbon dioxide fixation
KW - cyclic carbonates
KW - epoxides
KW - homogeneous catalysts
KW - porphyrinoids
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U2 - 10.1002/chem.201600164
DO - 10.1002/chem.201600164
M3 - Article
AN - SCOPUS:84961285194
VL - 22
SP - 6556
EP - 6563
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 19
ER -