Sulphur <i>vs</i> NH Group: Effects on the CO<sub>2</sub> Electroreduction Capability of Phenylenediamine-Cp Cobalt Complexes
The cobalt complex (<b>I</b>) with cyclopentadienyl and 2-aminothiophenolate ligands was investigated as a homogeneous catalyst for electrochemical CO<sub>2</sub> reduction. By comparing its behavior with an analogous complex with the phenylenediamine (<b>II</b>),...
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MDPI AG
2023-03-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/28/5/2364 |
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| author | Nicola Melis Francesca Mocci Annalisa Vacca Luca Pilia |
| author_facet | Nicola Melis Francesca Mocci Annalisa Vacca Luca Pilia |
| author_sort | Nicola Melis |
| collection | DOAJ |
| description | The cobalt complex (<b>I</b>) with cyclopentadienyl and 2-aminothiophenolate ligands was investigated as a homogeneous catalyst for electrochemical CO<sub>2</sub> reduction. By comparing its behavior with an analogous complex with the phenylenediamine (<b>II</b>), the effect of sulfur atom as a substituent has been evaluated. As a result, a positive shift of the reduction potential and the reversibility of the corresponding redox process have been observed, also suggesting a higher stability of the compound with sulfur. Under anhydrous conditions, complex <b>I</b> showed a higher current enhancement in the presence of CO<sub>2</sub> (9.41) in comparison with <b>II</b> (4.12). Moreover, the presence of only one -NH group in <b>I</b> explained the difference in the observed increases on the catalytic activity toward CO<sub>2</sub> due to the presence of water, with current enhancements of 22.73 and 24.40 for <b>I</b> and <b>II</b>, respectively. DFT calculations confirmed the effect of sulfur on the lowering of the energy of the frontier orbitals of <b>I</b>, highlighted by electrochemical measurements. Furthermore, the condensed Fukui function <b><i>f <sup>−</sup></i></b> values agreed very well with the current enhancement observed in the absence of water. |
| first_indexed | 2024-03-11T07:16:49Z |
| format | Article |
| id | doaj.art-9a02b5680a2849849d3141d2c982e3a4 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-11T07:16:49Z |
| publishDate | 2023-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-9a02b5680a2849849d3141d2c982e3a42023-11-17T08:15:40ZengMDPI AGMolecules1420-30492023-03-01285236410.3390/molecules28052364Sulphur <i>vs</i> NH Group: Effects on the CO<sub>2</sub> Electroreduction Capability of Phenylenediamine-Cp Cobalt ComplexesNicola Melis0Francesca Mocci1Annalisa Vacca2Luca Pilia3Dipartimento di Ingegneria Meccanica, Chimica e dei Materiali (DIMCM), Università degli Studi di Cagliari, Via Marengo 2, 09123 Cagliari, ItalyDipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, S.S. 554 km 4.500, 09042 Monserrato, ItalyDipartimento di Ingegneria Meccanica, Chimica e dei Materiali (DIMCM), Università degli Studi di Cagliari, Via Marengo 2, 09123 Cagliari, ItalyDipartimento di Ingegneria Meccanica, Chimica e dei Materiali (DIMCM), Università degli Studi di Cagliari, Via Marengo 2, 09123 Cagliari, ItalyThe cobalt complex (<b>I</b>) with cyclopentadienyl and 2-aminothiophenolate ligands was investigated as a homogeneous catalyst for electrochemical CO<sub>2</sub> reduction. By comparing its behavior with an analogous complex with the phenylenediamine (<b>II</b>), the effect of sulfur atom as a substituent has been evaluated. As a result, a positive shift of the reduction potential and the reversibility of the corresponding redox process have been observed, also suggesting a higher stability of the compound with sulfur. Under anhydrous conditions, complex <b>I</b> showed a higher current enhancement in the presence of CO<sub>2</sub> (9.41) in comparison with <b>II</b> (4.12). Moreover, the presence of only one -NH group in <b>I</b> explained the difference in the observed increases on the catalytic activity toward CO<sub>2</sub> due to the presence of water, with current enhancements of 22.73 and 24.40 for <b>I</b> and <b>II</b>, respectively. DFT calculations confirmed the effect of sulfur on the lowering of the energy of the frontier orbitals of <b>I</b>, highlighted by electrochemical measurements. Furthermore, the condensed Fukui function <b><i>f <sup>−</sup></i></b> values agreed very well with the current enhancement observed in the absence of water.https://www.mdpi.com/1420-3049/28/5/2364electrochemistryreductionCO<sub>2</sub>cobalt complexcyclic voltammetrycondensed Fukui function |
| spellingShingle | Nicola Melis Francesca Mocci Annalisa Vacca Luca Pilia Sulphur <i>vs</i> NH Group: Effects on the CO<sub>2</sub> Electroreduction Capability of Phenylenediamine-Cp Cobalt Complexes Molecules electrochemistry reduction CO<sub>2</sub> cobalt complex cyclic voltammetry condensed Fukui function |
| title | Sulphur <i>vs</i> NH Group: Effects on the CO<sub>2</sub> Electroreduction Capability of Phenylenediamine-Cp Cobalt Complexes |
| title_full | Sulphur <i>vs</i> NH Group: Effects on the CO<sub>2</sub> Electroreduction Capability of Phenylenediamine-Cp Cobalt Complexes |
| title_fullStr | Sulphur <i>vs</i> NH Group: Effects on the CO<sub>2</sub> Electroreduction Capability of Phenylenediamine-Cp Cobalt Complexes |
| title_full_unstemmed | Sulphur <i>vs</i> NH Group: Effects on the CO<sub>2</sub> Electroreduction Capability of Phenylenediamine-Cp Cobalt Complexes |
| title_short | Sulphur <i>vs</i> NH Group: Effects on the CO<sub>2</sub> Electroreduction Capability of Phenylenediamine-Cp Cobalt Complexes |
| title_sort | sulphur i vs i nh group effects on the co sub 2 sub electroreduction capability of phenylenediamine cp cobalt complexes |
| topic | electrochemistry reduction CO<sub>2</sub> cobalt complex cyclic voltammetry condensed Fukui function |
| url | https://www.mdpi.com/1420-3049/28/5/2364 |
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