Exploring Protonation Sites with Cation-Responsive Polyethylene glycol (PEG) Tethers in [FeFe]-Hydrogenase Mimics
Mimics of [FeFe]-hydrogenases having two [(μ-adt)Fe2(CO)6] moieties linked through 1,2,3-triazole rings with polyethylene glycol (PEG) chains [(–OCH2CH2O–)4 (7) and (–OCH2CH2O–)5 (8)] are able to coordinate to alkali ions (Na+, K+) via the O-PEG atoms and the triazole-N3 positions. Electrocatalytic...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/124054 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/124054 |
| Access Level: | acceso abierto |
| Palabra clave: | 547 Ciencias 2306 Química Orgánica 2303 Química Inorgánica |
| Sumario: | Mimics of [FeFe]-hydrogenases having two [(μ-adt)Fe2(CO)6] moieties linked through 1,2,3-triazole rings with polyethylene glycol (PEG) chains [(–OCH2CH2O–)4 (7) and (–OCH2CH2O–)5 (8)] are able to coordinate to alkali ions (Na+, K+) via the O-PEG atoms and the triazole-N3 positions. Electrocatalytic studies in trifluoroacetic acid (TFA) demonstrate that their catalytic performance is affected by the presence of Na+ and K+ salts. The addition of NaPF6 decreases the electrocatalytic activity of 7 and 8 (about 50% reduction of the TOF values). As, in TFA, 7 and 8 could be protonated in both the triazole and adt-amino groups, the reduction in TOF values suggests that NaPF6 inhibits the contribution of the triazolium species to the electrocatalytic process, likely due to the involvement of the triazole-N3 positions in Na+ binding. However, the addition of KPF6 either does not change (7) or increases the TOF values (8). 1H NMR titration experiments demonstrate that, despite the presence of K+ ions in the media, triazolium salts are formed. Therefore, the TOF values should reflect the contribution of species protonated in both the triazole and adt-amino groups to the HER process. |
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