2,2'-Bipyridine Equipped with a Disulfide/Dithiol Switch for Coupled Two Electron and Proton Transfer
[1,2]dithiino[4,3-b:5,6-b´]dipyridine (1) and its protonated open form 3,3´-dithiol-2,2´-bipyridine (2) were synthesised and their interconversion investigated. The X-ray structure of 2 revealed an anti orientation of the two pyridine units and a zwitterionic form. In depth electrochemical studies i...
| Autores: | , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2018 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/85505 |
| Acceso en línea: | http://hdl.handle.net/11336/85505 |
| Access Level: | acceso abierto |
| Palabra clave: | disulfide bipyridine ligands multiredox https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Sumario: | [1,2]dithiino[4,3-b:5,6-b´]dipyridine (1) and its protonated open form 3,3´-dithiol-2,2´-bipyridine (2) were synthesised and their interconversion investigated. The X-ray structure of 2 revealed an anti orientation of the two pyridine units and a zwitterionic form. In depth electrochemical studies in combination with DFT calculations lead to a comprehensive picture of the redox chemistry of 1 in the absence and presence of protons. Initial one electron reduction at E1 = −1.97 V results in the formation of the radical anion 1red with much elongated S-S bond, which readily undergoes further reduction at E2 = −2.15 V. Water triggers a potential inversion (E ≥ −1.9 V for the second reduction) as the radical anion 1red is protonated at its basic N atom. DFT studies revealed that S−S bond breaking and twisting of the pyridine units generally occurs after the second reduction step while the potential inversion induced by protonation is a result of charge compensation. The CV data were simulated to derive rate constants for the individual chemical and electrochemical reactions for both scenarios in the absence and presence of protons. |
|---|