Carbon Dioxide Hydrogenation and Formic Acid Dehydrogenation Catalyzed by Iridium Complexes Bearing Pyridyl-pyrazole Ligands

Effect of an Electron-donating Substituent on the Pyrazole Ring on the Catalytic Activity and Durability

Naoya Onishi, Ryoichi Kanega, Etsuko Fujita, Yuichiro Himeda

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Cp*Ir (Cp*=pentamethylcyclopentadienyl) complexes with an N,N-bidentate ligand such as 2,2′-bipyridine serve as catalysts for both carbon dioxide (CO2) hydrogenation to formate and formic acid dehydrogenation in water. Previously, it was shown that the introduction of an electron-donating substituent on 2,2′-bipyridine is an effective method to improve the catalytic activity. Especially, the highly electron-donating hydroxyl (OH) substituent performs much better than other substituents such as methyl or methoxy under basic conditions. However, the introduction of an OH substituent on the ligand has been limited to six-membered rings such as pyridine or pyrimidine. These results prompted us to develop a new ligand comprising a pyridyl-pyrazole with an OH group on the pyrazole moiety for Cp*Ir-catalyzed CO2 hydrogenation and formic acid dehydrogenation. The resultant catalyst showed high catalytic activity in CO2 hydrogenation and excellent robustness in formic acid dehydrogenation with a turnover number of 10 million. (Figure presented.).

Original languageEnglish
JournalAdvanced Synthesis and Catalysis
DOIs
Publication statusAccepted/In press - Jan 1 2018

Fingerprint

formic acid
Bearings (structural)
Iridium
Formic acid
Dehydrogenation
Carbon Dioxide
Hydrogenation
Catalyst activity
Carbon dioxide
Durability
Ligands
Electrons
Catalysts
Pyridine
Hydroxyl Radical
pyrazole
Water

Keywords

  • CO hydrogenation
  • Formic acid dehydrogenation
  • Hydrogen storage
  • Iridium catalyst

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

Cite this

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title = "Carbon Dioxide Hydrogenation and Formic Acid Dehydrogenation Catalyzed by Iridium Complexes Bearing Pyridyl-pyrazole Ligands: Effect of an Electron-donating Substituent on the Pyrazole Ring on the Catalytic Activity and Durability",
abstract = "Cp*Ir (Cp*=pentamethylcyclopentadienyl) complexes with an N,N-bidentate ligand such as 2,2′-bipyridine serve as catalysts for both carbon dioxide (CO2) hydrogenation to formate and formic acid dehydrogenation in water. Previously, it was shown that the introduction of an electron-donating substituent on 2,2′-bipyridine is an effective method to improve the catalytic activity. Especially, the highly electron-donating hydroxyl (OH) substituent performs much better than other substituents such as methyl or methoxy under basic conditions. However, the introduction of an OH substituent on the ligand has been limited to six-membered rings such as pyridine or pyrimidine. These results prompted us to develop a new ligand comprising a pyridyl-pyrazole with an OH group on the pyrazole moiety for Cp*Ir-catalyzed CO2 hydrogenation and formic acid dehydrogenation. The resultant catalyst showed high catalytic activity in CO2 hydrogenation and excellent robustness in formic acid dehydrogenation with a turnover number of 10 million. (Figure presented.).",
keywords = "CO hydrogenation, Formic acid dehydrogenation, Hydrogen storage, Iridium catalyst",
author = "Naoya Onishi and Ryoichi Kanega and Etsuko Fujita and Yuichiro Himeda",
year = "2018",
month = "1",
day = "1",
doi = "10.1002/adsc.201801323",
language = "English",
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TY - JOUR

T1 - Carbon Dioxide Hydrogenation and Formic Acid Dehydrogenation Catalyzed by Iridium Complexes Bearing Pyridyl-pyrazole Ligands

T2 - Effect of an Electron-donating Substituent on the Pyrazole Ring on the Catalytic Activity and Durability

AU - Onishi, Naoya

AU - Kanega, Ryoichi

AU - Fujita, Etsuko

AU - Himeda, Yuichiro

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Cp*Ir (Cp*=pentamethylcyclopentadienyl) complexes with an N,N-bidentate ligand such as 2,2′-bipyridine serve as catalysts for both carbon dioxide (CO2) hydrogenation to formate and formic acid dehydrogenation in water. Previously, it was shown that the introduction of an electron-donating substituent on 2,2′-bipyridine is an effective method to improve the catalytic activity. Especially, the highly electron-donating hydroxyl (OH) substituent performs much better than other substituents such as methyl or methoxy under basic conditions. However, the introduction of an OH substituent on the ligand has been limited to six-membered rings such as pyridine or pyrimidine. These results prompted us to develop a new ligand comprising a pyridyl-pyrazole with an OH group on the pyrazole moiety for Cp*Ir-catalyzed CO2 hydrogenation and formic acid dehydrogenation. The resultant catalyst showed high catalytic activity in CO2 hydrogenation and excellent robustness in formic acid dehydrogenation with a turnover number of 10 million. (Figure presented.).

AB - Cp*Ir (Cp*=pentamethylcyclopentadienyl) complexes with an N,N-bidentate ligand such as 2,2′-bipyridine serve as catalysts for both carbon dioxide (CO2) hydrogenation to formate and formic acid dehydrogenation in water. Previously, it was shown that the introduction of an electron-donating substituent on 2,2′-bipyridine is an effective method to improve the catalytic activity. Especially, the highly electron-donating hydroxyl (OH) substituent performs much better than other substituents such as methyl or methoxy under basic conditions. However, the introduction of an OH substituent on the ligand has been limited to six-membered rings such as pyridine or pyrimidine. These results prompted us to develop a new ligand comprising a pyridyl-pyrazole with an OH group on the pyrazole moiety for Cp*Ir-catalyzed CO2 hydrogenation and formic acid dehydrogenation. The resultant catalyst showed high catalytic activity in CO2 hydrogenation and excellent robustness in formic acid dehydrogenation with a turnover number of 10 million. (Figure presented.).

KW - CO hydrogenation

KW - Formic acid dehydrogenation

KW - Hydrogen storage

KW - Iridium catalyst

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