Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azides

In this work, the decomposition of a prototypical azide, isopropyl azide, both in the ground and excited states, has been investigated through the use of multiconfigurational CASSCF and MS-CASPT2 electronic structure approaches. Particular emphasis has been placed on the thermal reaction starting at...

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Detalhes bibliográficos
Autores: Soto, Juan, Algarra González, Manuel, Peláez, Daniel
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2022
País:España
Recursos:Universidad Pública de Navarra
Repositorio:Academica-e. Repositorio Institucional de la Universidad Pública de Navarra
OAI Identifier:oai:academica-e.unavarra.es:2454/43203
Acesso em linha:https://hdl.handle.net/2454/43203
Access Level:acceso abierto
Palavra-chave:Organiz azides
Isopropyl nitrene
CASSCF
MS-CASPT2
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spelling Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azidesSoto, JuanAlgarra González, ManuelPeláez, DanielOrganiz azidesIsopropyl nitreneCASSCFMS-CASPT2In this work, the decomposition of a prototypical azide, isopropyl azide, both in the ground and excited states, has been investigated through the use of multiconfigurational CASSCF and MS-CASPT2 electronic structure approaches. Particular emphasis has been placed on the thermal reaction starting at the S0 ground state surface. It has been found that the azide thermally decomposes via a stepwise mechanism, whose rate-determining step is the formation of isopropyl nitrene, which is, in turn, the first step of the global mechanism. After that, the nitrene isomerizes to the corresponding imine derivative. Two routes are possible for such a decomposition: (i) a spin-allowed path involving a transition state; and (ii) a spinforbidden one via a S0/T0 intersystem crossing. Both intermediates have been determined and characterised. Their associated relative energies have been found to be quite similar, 45.75 and 45.52 kcal mol1, respectively. To complete this study, the kinetics of the singlet and triplet channels are modeled with the MESMER (Master Equation Solver for Multi-Energy Well Reactions) code by applying the RRKM and Landau Zener (with WKB tunnelling correction) theories, respectively. It is found that the canonical rate-coefficients of the singlet path are 2-orders of magnitude higher than the ratecoefficients of the forbidden reaction. In addition, the concerted mechanism has been investigated that would lead to the formation of the imine derivative and nitrogen extrusion in the first step of the decomposition. After a careful analysis of CASSCF calculations with different active spaces and their comparison with single electronic configuration methods (MP2 and B3LYP), the concerted mechanism is discarded.This work has been supported by projects UMA18-FEDER-JA-049 and P18-RT-4592 of Junta de Andalucía and FEDER founds.Royal Society of ChemistryZientziakInstitute for Advanced Materials and Mathematics - INAMAT2Ciencias2022info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2454/43203reponame:Academica-e. Repositorio Institucional de la Universidad Pública de Navarrainstname:Universidad Pública de NavarraInglés© the Owner Societies 2022. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.https://creativecommons.org/licenses/by-nc/3.0/info:eu-repo/semantics/openAccessoai:academica-e.unavarra.es:2454/432032026-06-17T12:41:47Z
dc.title.none.fl_str_mv Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azides
title Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azides
spellingShingle Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azides
Soto, Juan
Organiz azides
Isopropyl nitrene
CASSCF
MS-CASPT2
title_short Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azides
title_full Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azides
title_fullStr Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azides
title_full_unstemmed Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azides
title_sort Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azides
dc.creator.none.fl_str_mv Soto, Juan
Algarra González, Manuel
Peláez, Daniel
author Soto, Juan
author_facet Soto, Juan
Algarra González, Manuel
Peláez, Daniel
author_role author
author2 Algarra González, Manuel
Peláez, Daniel
author2_role author
author
dc.contributor.none.fl_str_mv Zientziak
Institute for Advanced Materials and Mathematics - INAMAT2
Ciencias
dc.subject.none.fl_str_mv Organiz azides
Isopropyl nitrene
CASSCF
MS-CASPT2
topic Organiz azides
Isopropyl nitrene
CASSCF
MS-CASPT2
description In this work, the decomposition of a prototypical azide, isopropyl azide, both in the ground and excited states, has been investigated through the use of multiconfigurational CASSCF and MS-CASPT2 electronic structure approaches. Particular emphasis has been placed on the thermal reaction starting at the S0 ground state surface. It has been found that the azide thermally decomposes via a stepwise mechanism, whose rate-determining step is the formation of isopropyl nitrene, which is, in turn, the first step of the global mechanism. After that, the nitrene isomerizes to the corresponding imine derivative. Two routes are possible for such a decomposition: (i) a spin-allowed path involving a transition state; and (ii) a spinforbidden one via a S0/T0 intersystem crossing. Both intermediates have been determined and characterised. Their associated relative energies have been found to be quite similar, 45.75 and 45.52 kcal mol1, respectively. To complete this study, the kinetics of the singlet and triplet channels are modeled with the MESMER (Master Equation Solver for Multi-Energy Well Reactions) code by applying the RRKM and Landau Zener (with WKB tunnelling correction) theories, respectively. It is found that the canonical rate-coefficients of the singlet path are 2-orders of magnitude higher than the ratecoefficients of the forbidden reaction. In addition, the concerted mechanism has been investigated that would lead to the formation of the imine derivative and nitrogen extrusion in the first step of the decomposition. After a careful analysis of CASSCF calculations with different active spaces and their comparison with single electronic configuration methods (MP2 and B3LYP), the concerted mechanism is discarded.
publishDate 2022
dc.date.none.fl_str_mv 2022
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2454/43203
url https://hdl.handle.net/2454/43203
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv https://creativecommons.org/licenses/by-nc/3.0/
info:eu-repo/semantics/openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc/3.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Royal Society of Chemistry
publisher.none.fl_str_mv Royal Society of Chemistry
dc.source.none.fl_str_mv reponame:Academica-e. Repositorio Institucional de la Universidad Pública de Navarra
instname:Universidad Pública de Navarra
instname_str Universidad Pública de Navarra
reponame_str Academica-e. Repositorio Institucional de la Universidad Pública de Navarra
collection Academica-e. Repositorio Institucional de la Universidad Pública de Navarra
repository.name.fl_str_mv
repository.mail.fl_str_mv
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