Ligand dechelation effect on a [Co(tpy)2]2+ scaffold towards electro-catalytic proton and water reduction
| Autor: | Karunamay Majee, Sumanta Kumar Padhi |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Aqueous solution
Ligand Quinoline chemistry.chemical_element Protonation 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences Medicinal chemistry Catalysis Dissociation (chemistry) 0104 chemical sciences chemistry.chemical_compound chemistry Pyridine Materials Chemistry 0210 nano-technology Cobalt |
| Zdroj: | New Journal of Chemistry. 43:3856-3865 |
| ISSN: | 1369-9261 1144-0546 |
| DOI: | 10.1039/c8nj05712e |
| Popis: | This study presents the synthesis of the 4-(2,6-di(pyridin-2-yl)pyridin-4-yl)quinoline (4Ql-tpy) ligand and its corresponding cobalt complexes, i.e. [Co(4Ql-tpy)2]Cl2 and [Co(4Ql-tpy)2](PF6)3. The [Co(4Ql-tpy)2]Cl2 complex has been employed for electro-catalytic reduction of protons in DMF/H2O (95 : 5 v/v) as well as in phosphate buffer (pH 4.0–7.0). The spectroscopic investigations reveal the dissociation of one of the 4Ql-tpy ligands from the [Co(4Ql-tpy)2]Cl2 complex in the presence of excess AcOH in organic medium. However, in phosphate buffer it is evident that the dechelation of one of the peripheral pyridine rings followed by the protonation of pyridine-N occurs with the subsequent coordination of one water molecule. The aqueous electrochemical studies reveal that the Co(I) species is dependent on the proton concentration and the gradient for potential vs. pH indicates that a PCET (1H+/1e−) is involved between [CoII(4Ql-tpy)(24Ql-tpy)(OH2)]2+ and [CoI(4Ql-tpy)(24Ql-tpyH)(OH2)]2+ in the pH range 2.8 to 8.0. The plausible mechanism has been described based on the spectroscopic and electrochemical investigations. |
| Databáze: | OpenAIRE |
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