Dehydrogenation of Formic Acid Catalyzed by an Osmium-Polyhydride: relevance of Acid Assistance in the CO2 Formation Stage
Complex OsH4{κ1-P,η2-GeH-[iPr2PCH(Me)CH2GeEt2H]}(PiPr3) (1) breaks down formic acid into H2 and CO2. The decomposition is catalytic with complex 1 being the main metallic species detected spectroscopically during the process. The kinetic analysis of the catalysis reveals that the decomposition rate...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2024 |
| País: | España |
| Institución: | Universidad de Zaragoza |
| Repositorio: | Zaguán. Repositorio Digital de la Universidad de Zaragoza |
| OAI Identifier: | oai:zaguan.unizar.es:135485 |
| Acceso en línea: | http://zaguan.unizar.es/record/135485 |
| Access Level: | acceso abierto |
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oai:zaguan.unizar.es:135485 |
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España |
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Dehydrogenation of Formic Acid Catalyzed by an Osmium-Polyhydride: relevance of Acid Assistance in the CO2 Formation Stage Esteruelas, Miguel A. López, Ana M. Oñate, Enrique Raga, Esther Complex OsH4{κ1-P,η2-GeH-[iPr2PCH(Me)CH2GeEt2H]}(PiPr3) (1) breaks down formic acid into H2 and CO2. The decomposition is catalytic with complex 1 being the main metallic species detected spectroscopically during the process. The kinetic analysis of the catalysis reveals that the decomposition rate is first order in the catalyst and independent of the concentration of formic acid, with the calculated activation parameters being: ΔH⧧ = 23 ± 2 kcal mol–1, ΔS⧧ = −1 ± 5 cal mol–1 K–1, and 298ΔG⧧ = 23 ± 3 kcal mol–1. Complex 1 also shows stoichiometric reactivity with benzoic and acetic acids. The reactions lead to OsH2{κ2-O,O-[O2CR]}{κ2-P,Ge-[iPr2PCH(Me)CH2GeEt2]}(PiPr3) (R = Ph (9), Me (10)). On the basis of these findings and DFT calculations, the following mechanism for the decomposition is proposed: complex 1 releases one molecule of H2 to produce an osmium(IV)-trihydride unsaturated intermediate, which promotes heterolytic activation of the O–H bond of formic acid. The metal fragment of the resulting osmium(IV)-(κ1-O-formate)-saturated derivative slides along the formate group, following the O–C–H pathway. The displacement is assisted externally by a molecule of formic acid and generates an osmium(IV)-(κ1-H-formate) species, which releases CO2 to regenerate 1 and close a cycle. The dissociation of H2 from the latter is the rate-determining step of catalysis. http://zaguan.unizar.es/record/135485 |
| title |
Dehydrogenation of Formic Acid Catalyzed by an Osmium-Polyhydride: relevance of Acid Assistance in the CO2 Formation Stage |
| spellingShingle |
Dehydrogenation of Formic Acid Catalyzed by an Osmium-Polyhydride: relevance of Acid Assistance in the CO2 Formation Stage Esteruelas, Miguel A. |
| title_short |
Dehydrogenation of Formic Acid Catalyzed by an Osmium-Polyhydride: relevance of Acid Assistance in the CO2 Formation Stage |
| title_full |
Dehydrogenation of Formic Acid Catalyzed by an Osmium-Polyhydride: relevance of Acid Assistance in the CO2 Formation Stage |
| title_fullStr |
Dehydrogenation of Formic Acid Catalyzed by an Osmium-Polyhydride: relevance of Acid Assistance in the CO2 Formation Stage |
| title_full_unstemmed |
Dehydrogenation of Formic Acid Catalyzed by an Osmium-Polyhydride: relevance of Acid Assistance in the CO2 Formation Stage |
| title_sort |
Dehydrogenation of Formic Acid Catalyzed by an Osmium-Polyhydride: relevance of Acid Assistance in the CO2 Formation Stage |
| author |
Esteruelas, Miguel A. |
| author_facet |
Esteruelas, Miguel A. López, Ana M. Oñate, Enrique Raga, Esther |
| author_role |
author |
| author2 |
López, Ana M. Oñate, Enrique Raga, Esther |
| author2_role |
author author author |
| description |
Complex OsH4{κ1-P,η2-GeH-[iPr2PCH(Me)CH2GeEt2H]}(PiPr3) (1) breaks down formic acid into H2 and CO2. The decomposition is catalytic with complex 1 being the main metallic species detected spectroscopically during the process. The kinetic analysis of the catalysis reveals that the decomposition rate is first order in the catalyst and independent of the concentration of formic acid, with the calculated activation parameters being: ΔH⧧ = 23 ± 2 kcal mol–1, ΔS⧧ = −1 ± 5 cal mol–1 K–1, and 298ΔG⧧ = 23 ± 3 kcal mol–1. Complex 1 also shows stoichiometric reactivity with benzoic and acetic acids. The reactions lead to OsH2{κ2-O,O-[O2CR]}{κ2-P,Ge-[iPr2PCH(Me)CH2GeEt2]}(PiPr3) (R = Ph (9), Me (10)). On the basis of these findings and DFT calculations, the following mechanism for the decomposition is proposed: complex 1 releases one molecule of H2 to produce an osmium(IV)-trihydride unsaturated intermediate, which promotes heterolytic activation of the O–H bond of formic acid. The metal fragment of the resulting osmium(IV)-(κ1-O-formate)-saturated derivative slides along the formate group, following the O–C–H pathway. The displacement is assisted externally by a molecule of formic acid and generates an osmium(IV)-(κ1-H-formate) species, which releases CO2 to regenerate 1 and close a cycle. The dissociation of H2 from the latter is the rate-determining step of catalysis. |
| publishDate |
2024 |
| format |
article |
| status_str |
acceptedVersion |
| url |
http://zaguan.unizar.es/record/135485 |
| eu_rights_str_mv |
openAccess |
| institution |
Universidad de Zaragoza |
| collection |
Zaguán. Repositorio Digital de la Universidad de Zaragoza |
| reponame_str |
Zaguán. Repositorio Digital de la Universidad de Zaragoza |
| instname_str |
Universidad de Zaragoza |
| _version_ |
1878734459121958912 |
| publishDateSort |
2024 |
| author_browse |
Esteruelas, Miguel A. López, Ana M. Oñate, Enrique Raga, Esther |
| score |
6,8972664 |