Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions

Autores
Borba, Ana; Gomez Zavaglia, Andrea; Fausto, Rui
Año de publicación
2009
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
In this study, the structure, spectroscopy, and photochemistry of isoniazid (C6H7N3O, INH) were studied by low-temperature infrared spectroscopy and quantum chemistry calculations. According to DFT(B3LYP)/6-311++G(d,p) calculations, 12 minima were found on the potential energy surface of the molecule, corresponding to two cis conformers about the O=C-N-N axis (C1, C2) and one form trans about this axis (T), all being 4-fold degenerate by symmetry. The C1 conformer was predicted to be more stable than T and C2, by 20.4 and 22.6 kJ mol(-1), respectively. In consonance with these results, only C1 could be observed in low-temperature argon and xenon matrixes as well as in the neat glassy state prepared from the vapor of the compound at 70 degrees C. The C1 conformer was also found to be the constituting monomeric unit of the crystalline phase of INH produced from warming of the low-temperature neat amorphous state. The infrared spectra of INH in the different phases studied were fully assigned. After UV (lambda > 235 nm) irradiation of the matrix-isolated isoniazid, the compound was found to undergo photolysis through two different pathways: a Norris type I alpha-cleavage leading to production of isonicotinaldehyde and N2H2 and a concerted sigmatropic reaction with production of pyridine, CO and N2H2. The latter reaction was found to be nearly two times faster than the former in both argon and xenon matrixes. In addition, both reactions were found to be disfavored in a xenon matrix, which is in consonance with the involvement of (n, pi*) excited states in both photochemical processes.
Fil: Borba, Ana. Universidad de Coimbra; Portugal
Fil: Gomez Zavaglia, Andrea. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina
Fil: Fausto, Rui. Universidad de Coimbra; Portugal
Materia
Isoniazide
Cryogenic Conditions
Molecular structure
Infrared spectra
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/161802
Acceder
id CONICETDig_75f25708e016e46f37b108e1f8567ee3
oai_identifier_str oai:ri.conicet.gov.ar:11336/161802
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditionsBorba, AnaGomez Zavaglia, AndreaFausto, RuiIsoniazideCryogenic ConditionsMolecular structureInfrared spectrahttps://purl.org/becyt/ford/2.11https://purl.org/becyt/ford/2In this study, the structure, spectroscopy, and photochemistry of isoniazid (C6H7N3O, INH) were studied by low-temperature infrared spectroscopy and quantum chemistry calculations. According to DFT(B3LYP)/6-311++G(d,p) calculations, 12 minima were found on the potential energy surface of the molecule, corresponding to two cis conformers about the O=C-N-N axis (C1, C2) and one form trans about this axis (T), all being 4-fold degenerate by symmetry. The C1 conformer was predicted to be more stable than T and C2, by 20.4 and 22.6 kJ mol(-1), respectively. In consonance with these results, only C1 could be observed in low-temperature argon and xenon matrixes as well as in the neat glassy state prepared from the vapor of the compound at 70 degrees C. The C1 conformer was also found to be the constituting monomeric unit of the crystalline phase of INH produced from warming of the low-temperature neat amorphous state. The infrared spectra of INH in the different phases studied were fully assigned. After UV (lambda > 235 nm) irradiation of the matrix-isolated isoniazid, the compound was found to undergo photolysis through two different pathways: a Norris type I alpha-cleavage leading to production of isonicotinaldehyde and N2H2 and a concerted sigmatropic reaction with production of pyridine, CO and N2H2. The latter reaction was found to be nearly two times faster than the former in both argon and xenon matrixes. In addition, both reactions were found to be disfavored in a xenon matrix, which is in consonance with the involvement of (n, pi*) excited states in both photochemical processes.Fil: Borba, Ana. Universidad de Coimbra; PortugalFil: Gomez Zavaglia, Andrea. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Fausto, Rui. Universidad de Coimbra; PortugalAmerican Chemical Society2009-07info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/161802Borba, Ana; Gomez Zavaglia, Andrea; Fausto, Rui; Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions; American Chemical Society; Journal of Physical Chemistry A; 113; 32; 7-2009; 9220-92301089-56391520-5215CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://pubs.acs.org/doi/10.1021/jp9037914info:eu-repo/semantics/altIdentifier/doi/10.1021/jp9037914info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-03T09:48:01Zoai:ri.conicet.gov.ar:11336/161802instacron: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:34982025-09-03 09:48:02.088CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions
title Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions
spellingShingle Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions
Borba, Ana
Isoniazide
Cryogenic Conditions
Molecular structure
Infrared spectra
title_short Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions
title_full Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions
title_fullStr Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions
title_full_unstemmed Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions
title_sort Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions
dc.creator.none.fl_str_mv Borba, Ana
Gomez Zavaglia, Andrea
Fausto, Rui
author Borba, Ana
author_facet Borba, Ana
Gomez Zavaglia, Andrea
Fausto, Rui
author_role author
author2 Gomez Zavaglia, Andrea
Fausto, Rui
author2_role author
author
dc.subject.none.fl_str_mv Isoniazide
Cryogenic Conditions
Molecular structure
Infrared spectra
topic Isoniazide
Cryogenic Conditions
Molecular structure
Infrared spectra
purl_subject.fl_str_mv https://purl.org/becyt/ford/2.11
https://purl.org/becyt/ford/2
dc.description.none.fl_txt_mv In this study, the structure, spectroscopy, and photochemistry of isoniazid (C6H7N3O, INH) were studied by low-temperature infrared spectroscopy and quantum chemistry calculations. According to DFT(B3LYP)/6-311++G(d,p) calculations, 12 minima were found on the potential energy surface of the molecule, corresponding to two cis conformers about the O=C-N-N axis (C1, C2) and one form trans about this axis (T), all being 4-fold degenerate by symmetry. The C1 conformer was predicted to be more stable than T and C2, by 20.4 and 22.6 kJ mol(-1), respectively. In consonance with these results, only C1 could be observed in low-temperature argon and xenon matrixes as well as in the neat glassy state prepared from the vapor of the compound at 70 degrees C. The C1 conformer was also found to be the constituting monomeric unit of the crystalline phase of INH produced from warming of the low-temperature neat amorphous state. The infrared spectra of INH in the different phases studied were fully assigned. After UV (lambda > 235 nm) irradiation of the matrix-isolated isoniazid, the compound was found to undergo photolysis through two different pathways: a Norris type I alpha-cleavage leading to production of isonicotinaldehyde and N2H2 and a concerted sigmatropic reaction with production of pyridine, CO and N2H2. The latter reaction was found to be nearly two times faster than the former in both argon and xenon matrixes. In addition, both reactions were found to be disfavored in a xenon matrix, which is in consonance with the involvement of (n, pi*) excited states in both photochemical processes.
Fil: Borba, Ana. Universidad de Coimbra; Portugal
Fil: Gomez Zavaglia, Andrea. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina
Fil: Fausto, Rui. Universidad de Coimbra; Portugal
description In this study, the structure, spectroscopy, and photochemistry of isoniazid (C6H7N3O, INH) were studied by low-temperature infrared spectroscopy and quantum chemistry calculations. According to DFT(B3LYP)/6-311++G(d,p) calculations, 12 minima were found on the potential energy surface of the molecule, corresponding to two cis conformers about the O=C-N-N axis (C1, C2) and one form trans about this axis (T), all being 4-fold degenerate by symmetry. The C1 conformer was predicted to be more stable than T and C2, by 20.4 and 22.6 kJ mol(-1), respectively. In consonance with these results, only C1 could be observed in low-temperature argon and xenon matrixes as well as in the neat glassy state prepared from the vapor of the compound at 70 degrees C. The C1 conformer was also found to be the constituting monomeric unit of the crystalline phase of INH produced from warming of the low-temperature neat amorphous state. The infrared spectra of INH in the different phases studied were fully assigned. After UV (lambda > 235 nm) irradiation of the matrix-isolated isoniazid, the compound was found to undergo photolysis through two different pathways: a Norris type I alpha-cleavage leading to production of isonicotinaldehyde and N2H2 and a concerted sigmatropic reaction with production of pyridine, CO and N2H2. The latter reaction was found to be nearly two times faster than the former in both argon and xenon matrixes. In addition, both reactions were found to be disfavored in a xenon matrix, which is in consonance with the involvement of (n, pi*) excited states in both photochemical processes.
publishDate 2009
dc.date.none.fl_str_mv 2009-07
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/11336/161802
Borba, Ana; Gomez Zavaglia, Andrea; Fausto, Rui; Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions; American Chemical Society; Journal of Physical Chemistry A; 113; 32; 7-2009; 9220-9230
1089-5639
1520-5215
CONICET Digital
CONICET
url http://hdl.handle.net/11336/161802
identifier_str_mv Borba, Ana; Gomez Zavaglia, Andrea; Fausto, Rui; Molecular structure, infrared spectra, and photochemistry of isoniazid under cryogenic conditions; American Chemical Society; Journal of Physical Chemistry A; 113; 32; 7-2009; 9220-9230
1089-5639
1520-5215
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/jp9037914
info:eu-repo/semantics/altIdentifier/doi/10.1021/jp9037914
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/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
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score 13.13397

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