Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts
Iridium(I) compounds featuring bridge-functionalized bis-NHC ligands (NHC = N-heterocyclic carbene), [Ir(cod)(bis-NHC)] and [Ir(CO)<sub>2</sub>(bis-NHC)], have been prepared from the appropriate carboxylate- or hydroxy-functionalized bis-imidazolium salts. The related complexes [Ir(cod)(...
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| Format: | Article |
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MDPI AG
2022-11-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/27/22/7666 |
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| author | M. Victoria Jiménez Ana I. Ojeda-Amador Raquel Puerta-Oteo Joaquín Martínez-Sal Vincenzo Passarelli Jesús J. Pérez-Torrente |
| author_facet | M. Victoria Jiménez Ana I. Ojeda-Amador Raquel Puerta-Oteo Joaquín Martínez-Sal Vincenzo Passarelli Jesús J. Pérez-Torrente |
| author_sort | M. Victoria Jiménez |
| collection | DOAJ |
| description | Iridium(I) compounds featuring bridge-functionalized bis-NHC ligands (NHC = N-heterocyclic carbene), [Ir(cod)(bis-NHC)] and [Ir(CO)<sub>2</sub>(bis-NHC)], have been prepared from the appropriate carboxylate- or hydroxy-functionalized bis-imidazolium salts. The related complexes [Ir(cod)(NHC)<sub>2</sub>]<sup>+</sup> and [IrCl(cod)(NHC)(cod)] have been synthesized from a 3-hydroxypropyl functionalized imidazolium salt. These complexes have been shown to be robust catalysts in the oxidative dehydrogenation of glycerol to lactate (LA) with dihydrogen release. High activity and selectivity to LA were achieved in an open system under low catalyst loadings using KOH as a base. The hydroxy-functionalized bis-NHC catalysts are much more active than both the carboxylate-functionalized ones and the unbridged bis-NHC iridium(I) catalyst with hydroxyalkyl-functionalized NHC ligands. In general, carbonyl complexes are more active than the related 1,5-cyclooctadiene ones. The catalyst [Ir(CO)<sub>2</sub>{(MeImCH<sub>2</sub>)<sub>2</sub>CHOH}]Br exhibits the highest productivity affording TONs to LA up to 15,000 at very low catalyst loadings. |
| first_indexed | 2024-03-09T18:08:12Z |
| format | Article |
| id | doaj.art-ac0df0faced948d9852c36881cff75c7 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-09T18:08:12Z |
| publishDate | 2022-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-ac0df0faced948d9852c36881cff75c72023-11-24T09:19:04ZengMDPI AGMolecules1420-30492022-11-012722766610.3390/molecules27227666Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC CatalystsM. Victoria Jiménez0Ana I. Ojeda-Amador1Raquel Puerta-Oteo2Joaquín Martínez-Sal3Vincenzo Passarelli4Jesús J. Pérez-Torrente5Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea-ISQCH, Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, SpainDepartamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea-ISQCH, Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, SpainDepartamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea-ISQCH, Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, SpainDepartamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea-ISQCH, Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, SpainDepartamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea-ISQCH, Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, SpainDepartamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea-ISQCH, Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, SpainIridium(I) compounds featuring bridge-functionalized bis-NHC ligands (NHC = N-heterocyclic carbene), [Ir(cod)(bis-NHC)] and [Ir(CO)<sub>2</sub>(bis-NHC)], have been prepared from the appropriate carboxylate- or hydroxy-functionalized bis-imidazolium salts. The related complexes [Ir(cod)(NHC)<sub>2</sub>]<sup>+</sup> and [IrCl(cod)(NHC)(cod)] have been synthesized from a 3-hydroxypropyl functionalized imidazolium salt. These complexes have been shown to be robust catalysts in the oxidative dehydrogenation of glycerol to lactate (LA) with dihydrogen release. High activity and selectivity to LA were achieved in an open system under low catalyst loadings using KOH as a base. The hydroxy-functionalized bis-NHC catalysts are much more active than both the carboxylate-functionalized ones and the unbridged bis-NHC iridium(I) catalyst with hydroxyalkyl-functionalized NHC ligands. In general, carbonyl complexes are more active than the related 1,5-cyclooctadiene ones. The catalyst [Ir(CO)<sub>2</sub>{(MeImCH<sub>2</sub>)<sub>2</sub>CHOH}]Br exhibits the highest productivity affording TONs to LA up to 15,000 at very low catalyst loadings.https://www.mdpi.com/1420-3049/27/22/7666glycerollactic aciddehydrogenationhydrogen releaseN-heterocyclic carbenesiridium |
| spellingShingle | M. Victoria Jiménez Ana I. Ojeda-Amador Raquel Puerta-Oteo Joaquín Martínez-Sal Vincenzo Passarelli Jesús J. Pérez-Torrente Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts Molecules glycerol lactic acid dehydrogenation hydrogen release N-heterocyclic carbenes iridium |
| title | Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts |
| title_full | Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts |
| title_fullStr | Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts |
| title_full_unstemmed | Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts |
| title_short | Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts |
| title_sort | selective oxidation of glycerol via acceptorless dehydrogenation driven by ir i nhc catalysts |
| topic | glycerol lactic acid dehydrogenation hydrogen release N-heterocyclic carbenes iridium |
| url | https://www.mdpi.com/1420-3049/27/22/7666 |
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