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 - 2019/1/22
Y1 - 2019/1/22
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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U2 - 10.1002/adsc.201801323
DO - 10.1002/adsc.201801323
M3 - Article
AN - SCOPUS:85057499683
VL - 361
SP - 289
EP - 296
JO - Journal fur Praktische Chemie
JF - Journal fur Praktische Chemie
SN - 1436-9966
IS - 2
ER -