Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calcula...
- Autores
- Davila, Yamina Andrea; Sancho, Matias Israel; Almandoz, María C.; Blanco, Sonia Encarnacion
- Año de publicación
- 2013
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- The acid dissociation constants (pKa) of 7-hydroxyflavone, 3-hydroxyflavone and 5-hydroxyflavone, which are practically insoluble compounds in water but of great biological and physicochemical interest, were determined by UV–visible spectroscopy in ethanol–water and acetonitrile–water solutions, varying the solvent relative permittivity in the interval of 61 to 75, at constant ionic strength (0.050 mol·kg–1) and temperature (298.15 K). The pKa values of the compounds increase as the permittivity of the reaction medium decreases. Correlations were established between the pKa values and empirical parameters of the solvents, such as the relative permittivity and hydrogen-bond donor capacity. These equations allow the interpretation of the solvent effect on the acid–base equilibria and the determination of pKa values at 298.15 K in pure water. The ordering of the pKa values was 7-hydroxyflavone (7.28) < 3-hydroxyflavone (8.68) < 5-hydroxyflavone (11.75). In addition, the dissociation constants were also calculated by means of DFT methods (B3LYP/6-311+G(2d,p) level of theory), employing several thermodynamic cycles. The solvent effect on the optimized structures in the gas-phase was evaluated using the polarizable continuum model. A good agreement was observed between the theoretical and experimental pKa values. Finally, the experimental ordering in the acidity of the hydroxyflavones was explained using natural bond orbital analysis.
Fil: Davila, Yamina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigación Biológica de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; Argentina
Fil: Sancho, Matias Israel. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina
Fil: Almandoz, María C.. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina
Fil: Blanco, Sonia Encarnacion. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigación Biológica de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; Argentina - Materia
-
Pka
Solvent-Effect
Flavonoids
Dft - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
- Repositorio
- Institución
- Consejo Nacional de Investigaciones Científicas y Técnicas
- OAI Identificador
- oai:ri.conicet.gov.ar:11336/4390
Ver los metadatos del registro completo
id |
CONICETDig_48fefc5f33d62327685c2fbe683626eb |
---|---|
oai_identifier_str |
oai:ri.conicet.gov.ar:11336/4390 |
network_acronym_str |
CONICETDig |
repository_id_str |
3498 |
network_name_str |
CONICET Digital (CONICET) |
spelling |
Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT CalculationsDavila, Yamina AndreaSancho, Matias IsraelAlmandoz, María C.Blanco, Sonia EncarnacionPkaSolvent-EffectFlavonoidsDfthttps://purl.org/becyt/ford/1.4https://purl.org/becyt/ford/1The acid dissociation constants (pKa) of 7-hydroxyflavone, 3-hydroxyflavone and 5-hydroxyflavone, which are practically insoluble compounds in water but of great biological and physicochemical interest, were determined by UV–visible spectroscopy in ethanol–water and acetonitrile–water solutions, varying the solvent relative permittivity in the interval of 61 to 75, at constant ionic strength (0.050 mol·kg–1) and temperature (298.15 K). The pKa values of the compounds increase as the permittivity of the reaction medium decreases. Correlations were established between the pKa values and empirical parameters of the solvents, such as the relative permittivity and hydrogen-bond donor capacity. These equations allow the interpretation of the solvent effect on the acid–base equilibria and the determination of pKa values at 298.15 K in pure water. The ordering of the pKa values was 7-hydroxyflavone (7.28) < 3-hydroxyflavone (8.68) < 5-hydroxyflavone (11.75). In addition, the dissociation constants were also calculated by means of DFT methods (B3LYP/6-311+G(2d,p) level of theory), employing several thermodynamic cycles. The solvent effect on the optimized structures in the gas-phase was evaluated using the polarizable continuum model. A good agreement was observed between the theoretical and experimental pKa values. Finally, the experimental ordering in the acidity of the hydroxyflavones was explained using natural bond orbital analysis.Fil: Davila, Yamina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigación Biológica de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; ArgentinaFil: Sancho, Matias Israel. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Almandoz, María C.. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Blanco, Sonia Encarnacion. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigación Biológica de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; ArgentinaAmerican Chemical Society2013-06info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/4390Davila, Yamina Andrea; Sancho, Matias Israel; Almandoz, María C.; Blanco, Sonia Encarnacion; Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calculations; American Chemical Society; Journal of Chemical and Engineering Data; 58; 6; 6-2013; 1706-17160021-9568enginfo:eu-repo/semantics/altIdentifier/url/http://pubs.acs.org/doi/abs/10.1021/je400153rinfo:eu-repo/semantics/altIdentifier/doi/DOI:10.1021/je400153rinfo:eu-repo/semantics/altIdentifier/issn/0021-9568info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:12:38Zoai:ri.conicet.gov.ar:11336/4390instacron: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:34982025-09-29 10:12:38.925CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse |
dc.title.none.fl_str_mv |
Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calculations |
title |
Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calculations |
spellingShingle |
Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calculations Davila, Yamina Andrea Pka Solvent-Effect Flavonoids Dft |
title_short |
Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calculations |
title_full |
Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calculations |
title_fullStr |
Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calculations |
title_full_unstemmed |
Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calculations |
title_sort |
Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calculations |
dc.creator.none.fl_str_mv |
Davila, Yamina Andrea Sancho, Matias Israel Almandoz, María C. Blanco, Sonia Encarnacion |
author |
Davila, Yamina Andrea |
author_facet |
Davila, Yamina Andrea Sancho, Matias Israel Almandoz, María C. Blanco, Sonia Encarnacion |
author_role |
author |
author2 |
Sancho, Matias Israel Almandoz, María C. Blanco, Sonia Encarnacion |
author2_role |
author author author |
dc.subject.none.fl_str_mv |
Pka Solvent-Effect Flavonoids Dft |
topic |
Pka Solvent-Effect Flavonoids Dft |
purl_subject.fl_str_mv |
https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
dc.description.none.fl_txt_mv |
The acid dissociation constants (pKa) of 7-hydroxyflavone, 3-hydroxyflavone and 5-hydroxyflavone, which are practically insoluble compounds in water but of great biological and physicochemical interest, were determined by UV–visible spectroscopy in ethanol–water and acetonitrile–water solutions, varying the solvent relative permittivity in the interval of 61 to 75, at constant ionic strength (0.050 mol·kg–1) and temperature (298.15 K). The pKa values of the compounds increase as the permittivity of the reaction medium decreases. Correlations were established between the pKa values and empirical parameters of the solvents, such as the relative permittivity and hydrogen-bond donor capacity. These equations allow the interpretation of the solvent effect on the acid–base equilibria and the determination of pKa values at 298.15 K in pure water. The ordering of the pKa values was 7-hydroxyflavone (7.28) < 3-hydroxyflavone (8.68) < 5-hydroxyflavone (11.75). In addition, the dissociation constants were also calculated by means of DFT methods (B3LYP/6-311+G(2d,p) level of theory), employing several thermodynamic cycles. The solvent effect on the optimized structures in the gas-phase was evaluated using the polarizable continuum model. A good agreement was observed between the theoretical and experimental pKa values. Finally, the experimental ordering in the acidity of the hydroxyflavones was explained using natural bond orbital analysis. Fil: Davila, Yamina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigación Biológica de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; Argentina Fil: Sancho, Matias Israel. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina Fil: Almandoz, María C.. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina Fil: Blanco, Sonia Encarnacion. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigación Biológica de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Catedra de Quimica Fisica; Argentina |
description |
The acid dissociation constants (pKa) of 7-hydroxyflavone, 3-hydroxyflavone and 5-hydroxyflavone, which are practically insoluble compounds in water but of great biological and physicochemical interest, were determined by UV–visible spectroscopy in ethanol–water and acetonitrile–water solutions, varying the solvent relative permittivity in the interval of 61 to 75, at constant ionic strength (0.050 mol·kg–1) and temperature (298.15 K). The pKa values of the compounds increase as the permittivity of the reaction medium decreases. Correlations were established between the pKa values and empirical parameters of the solvents, such as the relative permittivity and hydrogen-bond donor capacity. These equations allow the interpretation of the solvent effect on the acid–base equilibria and the determination of pKa values at 298.15 K in pure water. The ordering of the pKa values was 7-hydroxyflavone (7.28) < 3-hydroxyflavone (8.68) < 5-hydroxyflavone (11.75). In addition, the dissociation constants were also calculated by means of DFT methods (B3LYP/6-311+G(2d,p) level of theory), employing several thermodynamic cycles. The solvent effect on the optimized structures in the gas-phase was evaluated using the polarizable continuum model. A good agreement was observed between the theoretical and experimental pKa values. Finally, the experimental ordering in the acidity of the hydroxyflavones was explained using natural bond orbital analysis. |
publishDate |
2013 |
dc.date.none.fl_str_mv |
2013-06 |
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/11336/4390 Davila, Yamina Andrea; Sancho, Matias Israel; Almandoz, María C.; Blanco, Sonia Encarnacion; Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calculations; American Chemical Society; Journal of Chemical and Engineering Data; 58; 6; 6-2013; 1706-1716 0021-9568 |
url |
http://hdl.handle.net/11336/4390 |
identifier_str_mv |
Davila, Yamina Andrea; Sancho, Matias Israel; Almandoz, María C.; Blanco, Sonia Encarnacion; Solvent Effects on the Dissociation Constants of Hydroxyflavones in Organic/Water Mixtures. Determination of the Thermodynamic pKa Values by UV/Visible Spectroscopy and DFT Calculations; American Chemical Society; Journal of Chemical and Engineering Data; 58; 6; 6-2013; 1706-1716 0021-9568 |
dc.language.none.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
info:eu-repo/semantics/altIdentifier/url/http://pubs.acs.org/doi/abs/10.1021/je400153r info:eu-repo/semantics/altIdentifier/doi/DOI:10.1021/je400153r info:eu-repo/semantics/altIdentifier/issn/0021-9568 |
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 application/pdf application/pdf 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_ |
1844614035714080768 |
score |
13.070432 |