Mechanistic versatility at Ir(PSiP) pincer catalysts: triflate proton shuttling from 2-Butyne to Diene and [3]Dendralene motifs

The five-coordinate hydrido complex [IrH(OTf)(PSiP)] (1) catalytically transforms 2-butyne into a mixture of its isomer 1,3-butadiene, and [3]dendralene and linear hexatriene dimerization products: (E)-4-methyl-3-methylene-1,4-hexadiene and (3Z)-3,4-dimethyl-1,3,5-hexatriene, respectively. Under the...

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Detalles Bibliográficos
Autores: Andrés, José L., Suárez, Elizabeth, Martín, Marta, Sola, Eduardo
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2022
País:España
Institución:Universidad de Zaragoza
Repositorio:Zaguán. Repositorio Digital de la Universidad de Zaragoza
OAI Identifier:oai:zaguan.unizar.es:120082
Acceso en línea:http://zaguan.unizar.es/record/120082
Access Level:acceso abierto
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spelling Mechanistic versatility at Ir(PSiP) pincer catalysts: triflate proton shuttling from 2-Butyne to Diene and [3]Dendralene motifsAndrés, José L.Suárez, ElizabethMartín, MartaSola, EduardoThe five-coordinate hydrido complex [IrH(OTf)(PSiP)] (1) catalytically transforms 2-butyne into a mixture of its isomer 1,3-butadiene, and [3]dendralene and linear hexatriene dimerization products: (E)-4-methyl-3-methylene-1,4-hexadiene and (3Z)-3,4-dimethyl-1,3,5-hexatriene, respectively. Under the conditions of the catalytic reaction, benzene, and 363 K, the hexatriene further undergoes thermal electrocyclization into 2,3-dimethyl-1,3-cyclohexadiene. The reactions between 1 and the alkyne substrate allow isolation or nuclear magnetic resonance (NMR) observation of catalyst resting states and possible reaction intermediates, including complexes with the former PSiP pincer ligands disassembled into PSi and PC chelates, and species coordinating allyl or carbene fragments en route to products. The density functional theory (DFT) calculations guided by these experimental observations disclose competing mechanisms for C–H bond elaboration that move H atoms either classically, as hydrides, or as protons transported by the triflate. This latter role of triflate, previously recognized only for more basic anions such as carboxylates, is discussed to result from combining the unfavorable charge separation in the nonpolar solvent and the low electronic demand from the metal to the anion at coordination positions trans to silicon. Triflate deprotonation of methyl groups is key to release highly coordinating diene products from stable allyl intermediates, thus enabling catalytic cycling.2022info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttp://zaguan.unizar.es/record/120082reponame:Zaguán. Repositorio Digital de la Universidad de Zaragozainstname:Universidad de ZaragozaInglésinfo:eu-repo/grantAgreement/ES/DGA/E50-20Dinfo:eu-repo/grantAgreement/ES/MINECO/BES-2013-063359info:eu-repo/grantAgreement/ES/MINECO/CTQ2012-31774info:eu-repo/semantics/openAccessoai:zaguan.unizar.es:1200822026-05-29T13:59:51Z
dc.title.none.fl_str_mv Mechanistic versatility at Ir(PSiP) pincer catalysts: triflate proton shuttling from 2-Butyne to Diene and [3]Dendralene motifs
title Mechanistic versatility at Ir(PSiP) pincer catalysts: triflate proton shuttling from 2-Butyne to Diene and [3]Dendralene motifs
spellingShingle Mechanistic versatility at Ir(PSiP) pincer catalysts: triflate proton shuttling from 2-Butyne to Diene and [3]Dendralene motifs
Andrés, José L.
title_short Mechanistic versatility at Ir(PSiP) pincer catalysts: triflate proton shuttling from 2-Butyne to Diene and [3]Dendralene motifs
title_full Mechanistic versatility at Ir(PSiP) pincer catalysts: triflate proton shuttling from 2-Butyne to Diene and [3]Dendralene motifs
title_fullStr Mechanistic versatility at Ir(PSiP) pincer catalysts: triflate proton shuttling from 2-Butyne to Diene and [3]Dendralene motifs
title_full_unstemmed Mechanistic versatility at Ir(PSiP) pincer catalysts: triflate proton shuttling from 2-Butyne to Diene and [3]Dendralene motifs
title_sort Mechanistic versatility at Ir(PSiP) pincer catalysts: triflate proton shuttling from 2-Butyne to Diene and [3]Dendralene motifs
dc.creator.none.fl_str_mv Andrés, José L.
Suárez, Elizabeth
Martín, Marta
Sola, Eduardo
author Andrés, José L.
author_facet Andrés, José L.
Suárez, Elizabeth
Martín, Marta
Sola, Eduardo
author_role author
author2 Suárez, Elizabeth
Martín, Marta
Sola, Eduardo
author2_role author
author
author
description The five-coordinate hydrido complex [IrH(OTf)(PSiP)] (1) catalytically transforms 2-butyne into a mixture of its isomer 1,3-butadiene, and [3]dendralene and linear hexatriene dimerization products: (E)-4-methyl-3-methylene-1,4-hexadiene and (3Z)-3,4-dimethyl-1,3,5-hexatriene, respectively. Under the conditions of the catalytic reaction, benzene, and 363 K, the hexatriene further undergoes thermal electrocyclization into 2,3-dimethyl-1,3-cyclohexadiene. The reactions between 1 and the alkyne substrate allow isolation or nuclear magnetic resonance (NMR) observation of catalyst resting states and possible reaction intermediates, including complexes with the former PSiP pincer ligands disassembled into PSi and PC chelates, and species coordinating allyl or carbene fragments en route to products. The density functional theory (DFT) calculations guided by these experimental observations disclose competing mechanisms for C–H bond elaboration that move H atoms either classically, as hydrides, or as protons transported by the triflate. This latter role of triflate, previously recognized only for more basic anions such as carboxylates, is discussed to result from combining the unfavorable charge separation in the nonpolar solvent and the low electronic demand from the metal to the anion at coordination positions trans to silicon. Triflate deprotonation of methyl groups is key to release highly coordinating diene products from stable allyl intermediates, thus enabling catalytic cycling.
publishDate 2022
dc.date.none.fl_str_mv 2022
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dc.identifier.none.fl_str_mv http://zaguan.unizar.es/record/120082
url http://zaguan.unizar.es/record/120082
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv info:eu-repo/grantAgreement/ES/DGA/E50-20D
info:eu-repo/grantAgreement/ES/MINECO/BES-2013-063359
info:eu-repo/grantAgreement/ES/MINECO/CTQ2012-31774
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
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