Characterization of Inherently Chiral Electrosynthesized Oligomeric Films by Voltammetry and Scanning Electrochemical Microscopy (SECM)
A voltammetric and scanning electrochemical microscopy (SECM) investigation was performed on an inherently chiral oligomer-coated gold electrode to establish its general properties (i.e., conductivity and topography), as well as its ability to discriminate chiral electroactive probe molecules. The e...
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| Format: | Article |
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MDPI AG
2020-11-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/25/22/5368 |
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| author | Margherita Donnici Rosanna Toniolo Serena Arnaboldi Patrizia R. Mussini Tiziana Benincori Roberto Cirilli Salvatore Daniele |
| author_facet | Margherita Donnici Rosanna Toniolo Serena Arnaboldi Patrizia R. Mussini Tiziana Benincori Roberto Cirilli Salvatore Daniele |
| author_sort | Margherita Donnici |
| collection | DOAJ |
| description | A voltammetric and scanning electrochemical microscopy (SECM) investigation was performed on an inherently chiral oligomer-coated gold electrode to establish its general properties (i.e., conductivity and topography), as well as its ability to discriminate chiral electroactive probe molecules. The electroactive monomer (<i>S</i>)-2,2′-bis(2,2′-bithiophene-5-yl)-3,3′-bibenzothiophene ((<i>S</i>)-BT<sub>2</sub>T<sub>4</sub>) was employed as reagent to electrodeposit, by cyclic voltammetry, the inherently chiral oligomer film of (<i>S</i>)-BT<sub>2</sub>T<sub>4</sub> (oligo-(<i>S</i>)-BT<sub>2</sub>T<sub>4</sub>) onto the Au electrode surface (resulting in oligo-(<i>S</i>)-BT<sub>2</sub>T<sub>4</sub>-Au). SECM measurements, performed in either feedback or competition mode, using the redox mediators [Fe(CN)<sub>6</sub>]<sup>4−</sup> and [Fe(CN)<sub>6</sub>]<sup>3−</sup> in aqueous solutions, and ferrocene (Fc), (<i>S</i>)-FcEA, (<i>R</i>)-FcEA and <i>rac-</i>FcEA (FcEA is <i>N</i>,<i>N</i>-dimethyl-1-ferrocenylethylamine) in CH<sub>3</sub>CN solutions, indicated that the oligomer film, as produced, was uncharged. The use of [Fe(CN)<sub>6</sub>]<sup>3−</sup> allowed establishing that the oligomer film behaved as a porous insulating membrane, presenting a rather rough surface. This was inferred from both the approach curves and linear and bidimensional SECM scans, which displayed negative feedback effects. The oligomer film acquired semiconducting or fully conducting properties when the Au electrode was biased at potential more positive than 0.6 V vs. Ag|AgCl|KCl. Under the latter conditions, the approach curves displayed positive feedback effects. SECM measurements, performed in competition mode, allowed verifying the discriminating ability of the oligo-(<i>S</i>)-BT<sub>2</sub>T<sub>4</sub> film towards the (<i>S</i>)-FcEA and (<i>R</i>)-FcEA redox mediators, which confirmed the results obtained by cyclic voltammetry. SECM linear scans indicated that the enantiomeric discriminating ability of the oligo-(<i>S</i>)-BT<sub>2</sub>T<sub>4</sub> was even across its entire surface. |
| first_indexed | 2024-03-10T14:47:40Z |
| format | Article |
| id | doaj.art-5469ccf57fb54e23ad46f080865f8778 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T14:47:40Z |
| publishDate | 2020-11-01 |
| publisher | MDPI AG |
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| series | Molecules |
| spelling | doaj.art-5469ccf57fb54e23ad46f080865f87782023-11-20T21:12:57ZengMDPI AGMolecules1420-30492020-11-012522536810.3390/molecules25225368Characterization of Inherently Chiral Electrosynthesized Oligomeric Films by Voltammetry and Scanning Electrochemical Microscopy (SECM)Margherita Donnici0Rosanna Toniolo1Serena Arnaboldi2Patrizia R. Mussini3Tiziana Benincori4Roberto Cirilli5Salvatore Daniele6Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, Via Torino 155, 30172 Mestre-Venezia, ItalyDipartimento di Scienze Agroalimentari, Ambientali e Animali, Università di Udine, Via Cotonificio 108, 33100 Udine, ItalyDipartimento di Chimica, Università degli Studi di Milano, 20133 Milano, ItalyDipartimento di Chimica, Università degli Studi di Milano, 20133 Milano, ItalyDipartimento di Scienza ed Alta Tecnologia, Università degli Studi dell’Insubria, 22100 Como, ItalyCentro Nazionale per il Controllo e la Valutazione dei Farmaci, Istituto Superiore di Sanità, 00161 Roma, ItalyDipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, Via Torino 155, 30172 Mestre-Venezia, ItalyA voltammetric and scanning electrochemical microscopy (SECM) investigation was performed on an inherently chiral oligomer-coated gold electrode to establish its general properties (i.e., conductivity and topography), as well as its ability to discriminate chiral electroactive probe molecules. The electroactive monomer (<i>S</i>)-2,2′-bis(2,2′-bithiophene-5-yl)-3,3′-bibenzothiophene ((<i>S</i>)-BT<sub>2</sub>T<sub>4</sub>) was employed as reagent to electrodeposit, by cyclic voltammetry, the inherently chiral oligomer film of (<i>S</i>)-BT<sub>2</sub>T<sub>4</sub> (oligo-(<i>S</i>)-BT<sub>2</sub>T<sub>4</sub>) onto the Au electrode surface (resulting in oligo-(<i>S</i>)-BT<sub>2</sub>T<sub>4</sub>-Au). SECM measurements, performed in either feedback or competition mode, using the redox mediators [Fe(CN)<sub>6</sub>]<sup>4−</sup> and [Fe(CN)<sub>6</sub>]<sup>3−</sup> in aqueous solutions, and ferrocene (Fc), (<i>S</i>)-FcEA, (<i>R</i>)-FcEA and <i>rac-</i>FcEA (FcEA is <i>N</i>,<i>N</i>-dimethyl-1-ferrocenylethylamine) in CH<sub>3</sub>CN solutions, indicated that the oligomer film, as produced, was uncharged. The use of [Fe(CN)<sub>6</sub>]<sup>3−</sup> allowed establishing that the oligomer film behaved as a porous insulating membrane, presenting a rather rough surface. This was inferred from both the approach curves and linear and bidimensional SECM scans, which displayed negative feedback effects. The oligomer film acquired semiconducting or fully conducting properties when the Au electrode was biased at potential more positive than 0.6 V vs. Ag|AgCl|KCl. Under the latter conditions, the approach curves displayed positive feedback effects. SECM measurements, performed in competition mode, allowed verifying the discriminating ability of the oligo-(<i>S</i>)-BT<sub>2</sub>T<sub>4</sub> film towards the (<i>S</i>)-FcEA and (<i>R</i>)-FcEA redox mediators, which confirmed the results obtained by cyclic voltammetry. SECM linear scans indicated that the enantiomeric discriminating ability of the oligo-(<i>S</i>)-BT<sub>2</sub>T<sub>4</sub> was even across its entire surface.https://www.mdpi.com/1420-3049/25/22/5368Inherently chiral oligomer filmschiral electroactive probesscanning electrochemical microscopyenantiodiscrimination in electrochemistry and electroanalysis |
| spellingShingle | Margherita Donnici Rosanna Toniolo Serena Arnaboldi Patrizia R. Mussini Tiziana Benincori Roberto Cirilli Salvatore Daniele Characterization of Inherently Chiral Electrosynthesized Oligomeric Films by Voltammetry and Scanning Electrochemical Microscopy (SECM) Molecules Inherently chiral oligomer films chiral electroactive probes scanning electrochemical microscopy enantiodiscrimination in electrochemistry and electroanalysis |
| title | Characterization of Inherently Chiral Electrosynthesized Oligomeric Films by Voltammetry and Scanning Electrochemical Microscopy (SECM) |
| title_full | Characterization of Inherently Chiral Electrosynthesized Oligomeric Films by Voltammetry and Scanning Electrochemical Microscopy (SECM) |
| title_fullStr | Characterization of Inherently Chiral Electrosynthesized Oligomeric Films by Voltammetry and Scanning Electrochemical Microscopy (SECM) |
| title_full_unstemmed | Characterization of Inherently Chiral Electrosynthesized Oligomeric Films by Voltammetry and Scanning Electrochemical Microscopy (SECM) |
| title_short | Characterization of Inherently Chiral Electrosynthesized Oligomeric Films by Voltammetry and Scanning Electrochemical Microscopy (SECM) |
| title_sort | characterization of inherently chiral electrosynthesized oligomeric films by voltammetry and scanning electrochemical microscopy secm |
| topic | Inherently chiral oligomer films chiral electroactive probes scanning electrochemical microscopy enantiodiscrimination in electrochemistry and electroanalysis |
| url | https://www.mdpi.com/1420-3049/25/22/5368 |
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