Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer

Autores
Williams, Nikki; Parnaik, Tanay; Dutta, Saptarshi; Bergen, Joseph; Cattaneo, Mauricio; Parada, Giovanny A.
Año de publicación
2025
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Multiple mechanisms have been proposed to explain the electrochemical proton-coupled electron transfer (PCET) of arylenediamines upon weak base addition in aprotic media. Similar to quinone electrochemistry, endergonic deprotonation to form freely diffusing products is a central criterion used to exclude proton transfer. However, the second oxidation wave of arylenediamines shows large, chemically reversible E1/2 shifts─often exceeding hundreds of millivolts─upon base addition. To explain these effects, proposed mechanisms invoke strong H-bonding or H-bonding followed by nonconcerted PCET. Here, we elucidate a new mechanism using cyclic voltammetry of a new arylenediamine series where the pKa is varied via π-electron spacers. A thermochemical analysis, based on equilibrium constants derived from biphasic E1/2 shifts observed from substoichiometric to excess base concentrations, supports a stepwise mechanism. This mechanism involves two sequential heterogeneous electron transfer steps (EE) followed by three homogeneous chemical steps (CCC), constituting an overall EECCC electrochemical mechanism. The CCC coupled equilibria correspond to exergonic H-bond precursor complex formation, thermoneutral proton transfer (PT), and endergonic successor complex dissociation. The energy well formed by the CCC coupled equilibria reconciles previous thermochemical analyses and provides a new explanation for chemically reversible electrochemical waves. Furthermore, a reactivity continuum between H-bonding and PT is demonstrated, which contrasts with the prevailing view, where either H-bonding or PT dominates the mechanism.
Fil: Williams, Nikki. The College Of New Jersey; Estados Unidos
Fil: Parnaik, Tanay. The College Of New Jersey; Estados Unidos
Fil: Dutta, Saptarshi. The College Of New Jersey; Estados Unidos
Fil: Bergen, Joseph. The College Of New Jersey; Estados Unidos
Fil: Cattaneo, Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentina
Fil: Parada, Giovanny A.. The College Of New Jersey; Estados Unidos
Materia
Mecanismo electroquímico
Puente hidrogeno
PCET
Multiredox
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/277471
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/277471
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron TransferWilliams, NikkiParnaik, TanayDutta, SaptarshiBergen, JosephCattaneo, MauricioParada, Giovanny A.Mecanismo electroquímicoPuente hidrogenoPCETMultiredoxhttps://purl.org/becyt/ford/1.4https://purl.org/becyt/ford/1Multiple mechanisms have been proposed to explain the electrochemical proton-coupled electron transfer (PCET) of arylenediamines upon weak base addition in aprotic media. Similar to quinone electrochemistry, endergonic deprotonation to form freely diffusing products is a central criterion used to exclude proton transfer. However, the second oxidation wave of arylenediamines shows large, chemically reversible E1/2 shifts─often exceeding hundreds of millivolts─upon base addition. To explain these effects, proposed mechanisms invoke strong H-bonding or H-bonding followed by nonconcerted PCET. Here, we elucidate a new mechanism using cyclic voltammetry of a new arylenediamine series where the pKa is varied via π-electron spacers. A thermochemical analysis, based on equilibrium constants derived from biphasic E1/2 shifts observed from substoichiometric to excess base concentrations, supports a stepwise mechanism. This mechanism involves two sequential heterogeneous electron transfer steps (EE) followed by three homogeneous chemical steps (CCC), constituting an overall EECCC electrochemical mechanism. The CCC coupled equilibria correspond to exergonic H-bond precursor complex formation, thermoneutral proton transfer (PT), and endergonic successor complex dissociation. The energy well formed by the CCC coupled equilibria reconciles previous thermochemical analyses and provides a new explanation for chemically reversible electrochemical waves. Furthermore, a reactivity continuum between H-bonding and PT is demonstrated, which contrasts with the prevailing view, where either H-bonding or PT dominates the mechanism.Fil: Williams, Nikki. The College Of New Jersey; Estados UnidosFil: Parnaik, Tanay. The College Of New Jersey; Estados UnidosFil: Dutta, Saptarshi. The College Of New Jersey; Estados UnidosFil: Bergen, Joseph. The College Of New Jersey; Estados UnidosFil: Cattaneo, Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Parada, Giovanny A.. The College Of New Jersey; Estados UnidosAmerican Chemical Society2025-10info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/277471Williams, Nikki; Parnaik, Tanay; Dutta, Saptarshi; Bergen, Joseph; Cattaneo, Mauricio; et al.; Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer; American Chemical Society; ACS Omega; 2025; 10-2025; 1-102470-1343CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://pubs.acs.org/doi/10.1021/acsomega.5c06783info:eu-repo/semantics/altIdentifier/doi/10.1021/acsomega.5c06783info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-12-23T13:28:03Zoai:ri.conicet.gov.ar:11336/277471instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-12-23 13:28:03.502CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer
title Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer
spellingShingle Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer
Williams, Nikki
Mecanismo electroquímico
Puente hidrogeno
PCET
Multiredox
title_short Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer
title_full Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer
title_fullStr Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer
title_full_unstemmed Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer
title_sort Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer
dc.creator.none.fl_str_mv Williams, Nikki
Parnaik, Tanay
Dutta, Saptarshi
Bergen, Joseph
Cattaneo, Mauricio
Parada, Giovanny A.
author Williams, Nikki
author_facet Williams, Nikki
Parnaik, Tanay
Dutta, Saptarshi
Bergen, Joseph
Cattaneo, Mauricio
Parada, Giovanny A.
author_role author
author2 Parnaik, Tanay
Dutta, Saptarshi
Bergen, Joseph
Cattaneo, Mauricio
Parada, Giovanny A.
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv Mecanismo electroquímico
Puente hidrogeno
PCET
Multiredox
topic Mecanismo electroquímico
Puente hidrogeno
PCET
Multiredox
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.4
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Multiple mechanisms have been proposed to explain the electrochemical proton-coupled electron transfer (PCET) of arylenediamines upon weak base addition in aprotic media. Similar to quinone electrochemistry, endergonic deprotonation to form freely diffusing products is a central criterion used to exclude proton transfer. However, the second oxidation wave of arylenediamines shows large, chemically reversible E1/2 shifts─often exceeding hundreds of millivolts─upon base addition. To explain these effects, proposed mechanisms invoke strong H-bonding or H-bonding followed by nonconcerted PCET. Here, we elucidate a new mechanism using cyclic voltammetry of a new arylenediamine series where the pKa is varied via π-electron spacers. A thermochemical analysis, based on equilibrium constants derived from biphasic E1/2 shifts observed from substoichiometric to excess base concentrations, supports a stepwise mechanism. This mechanism involves two sequential heterogeneous electron transfer steps (EE) followed by three homogeneous chemical steps (CCC), constituting an overall EECCC electrochemical mechanism. The CCC coupled equilibria correspond to exergonic H-bond precursor complex formation, thermoneutral proton transfer (PT), and endergonic successor complex dissociation. The energy well formed by the CCC coupled equilibria reconciles previous thermochemical analyses and provides a new explanation for chemically reversible electrochemical waves. Furthermore, a reactivity continuum between H-bonding and PT is demonstrated, which contrasts with the prevailing view, where either H-bonding or PT dominates the mechanism.
Fil: Williams, Nikki. The College Of New Jersey; Estados Unidos
Fil: Parnaik, Tanay. The College Of New Jersey; Estados Unidos
Fil: Dutta, Saptarshi. The College Of New Jersey; Estados Unidos
Fil: Bergen, Joseph. The College Of New Jersey; Estados Unidos
Fil: Cattaneo, Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentina
Fil: Parada, Giovanny A.. The College Of New Jersey; Estados Unidos
description Multiple mechanisms have been proposed to explain the electrochemical proton-coupled electron transfer (PCET) of arylenediamines upon weak base addition in aprotic media. Similar to quinone electrochemistry, endergonic deprotonation to form freely diffusing products is a central criterion used to exclude proton transfer. However, the second oxidation wave of arylenediamines shows large, chemically reversible E1/2 shifts─often exceeding hundreds of millivolts─upon base addition. To explain these effects, proposed mechanisms invoke strong H-bonding or H-bonding followed by nonconcerted PCET. Here, we elucidate a new mechanism using cyclic voltammetry of a new arylenediamine series where the pKa is varied via π-electron spacers. A thermochemical analysis, based on equilibrium constants derived from biphasic E1/2 shifts observed from substoichiometric to excess base concentrations, supports a stepwise mechanism. This mechanism involves two sequential heterogeneous electron transfer steps (EE) followed by three homogeneous chemical steps (CCC), constituting an overall EECCC electrochemical mechanism. The CCC coupled equilibria correspond to exergonic H-bond precursor complex formation, thermoneutral proton transfer (PT), and endergonic successor complex dissociation. The energy well formed by the CCC coupled equilibria reconciles previous thermochemical analyses and provides a new explanation for chemically reversible electrochemical waves. Furthermore, a reactivity continuum between H-bonding and PT is demonstrated, which contrasts with the prevailing view, where either H-bonding or PT dominates the mechanism.
publishDate 2025
dc.date.none.fl_str_mv 2025-10
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/277471
Williams, Nikki; Parnaik, Tanay; Dutta, Saptarshi; Bergen, Joseph; Cattaneo, Mauricio; et al.; Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer; American Chemical Society; ACS Omega; 2025; 10-2025; 1-10
2470-1343
CONICET Digital
CONICET
url http://hdl.handle.net/11336/277471
identifier_str_mv Williams, Nikki; Parnaik, Tanay; Dutta, Saptarshi; Bergen, Joseph; Cattaneo, Mauricio; et al.; Revisiting H-Bond v . PT: The Role of Precursor and Successor Complexes in Intermolecular, Stepwise Proton-Coupled Electron Transfer; American Chemical Society; ACS Omega; 2025; 10-2025; 1-10
2470-1343
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://pubs.acs.org/doi/10.1021/acsomega.5c06783
info:eu-repo/semantics/altIdentifier/doi/10.1021/acsomega.5c06783
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv American Chemical Society
publisher.none.fl_str_mv American Chemical Society
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
_version_ 1852335162365313024
score 12.952241

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