Visible light spectroscopic analysis of Methylene Blue in water; the resonance virtual equilibrium hypothesis

After a critical approach to the centennial literature on Methylene Blue self-aggregation in water, accurate visible-light absorption spectra and thermodynamic equilibrium constants for the monomeric and dimeric forms of this dye in water at different temperatures were obtained by means of a novel p...

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Authors: Fernández Pérez, Amparo, Valdés-Solís Iglesias, Teresa, Marbán Calzón, Gregorio
Format: article
Status:Versión aceptada para publicación
Publication Date:2018
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/202469
Online Access:http://hdl.handle.net/10261/202469
Access Level:Open access
Keyword:Methylene blue
Uv-visible spectrophotometry
Equilibrium constant
Thermo-solvatochromism
Self-aggregation
Resonance form
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spelling Visible light spectroscopic analysis of Methylene Blue in water; the resonance virtual equilibrium hypothesisFernández Pérez, AmparoValdés-Solís Iglesias, TeresaMarbán Calzón, GregorioMethylene blueUv-visible spectrophotometryEquilibrium constantThermo-solvatochromismSelf-aggregationResonance formAfter a critical approach to the centennial literature on Methylene Blue self-aggregation in water, accurate visible-light absorption spectra and thermodynamic equilibrium constants for the monomeric and dimeric forms of this dye in water at different temperatures were obtained by means of a novel procedure based on the Beer-Lambert equation. A thermo-solvatochromic effect was clearly detected in the monomer spectra, which we believe to be the main source of inaccuracy in all previous works. The only published explanation for this phenomenon, the existence of a colorless form of the monomer, is refuted here. Instead, a new notion has been introduced; the resonance virtual equilibrium hypothesis. According to this hypothesis the temperature-dependent absorption behavior of the monomer is provoked by the change in its electron charge distribution with the variation in the temperature-dependent dielectric constant of water. The monomer charge distribution stands between those of the virtual resonance forms, being the absorption spectrum of the monomer a composition of the theoretical spectra for the virtual mesomers, whose proportion is established by a temperature-dependent equilibrium constant. The application of this hypothesis allowed the virtual equilibrium constants and spectra for the mesomers to be evaluated with remarkable accuracy.The financial support for this research work provided by the Spanish MINECO (CTM2014-56770-R project) and FEDER Funds (GRUPIN14-102, Principado de Asturias) is gratefully acknowledged. AFP is grateful to the Spanish MINECO for the award of a contract (BES-2015-072274).Peer reviewedElsevierMinisterio de Economía y Competitividad (España)Principado de AsturiasValdés-Solís Iglesias, Teresa [0000-0003-0822-2292]Marbán Calzón, Gregorio [0000-0002-8387-3282]Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]202020202018info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Postprintinfo:eu-repo/semantics/acceptedVersionhttp://hdl.handle.net/10261/202469reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/CTM2014-56770-Rhttps://doi.org/10.1016/j.dyepig.2018.09.083Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/2024692026-05-22T06:33:51Z
dc.title.none.fl_str_mv Visible light spectroscopic analysis of Methylene Blue in water; the resonance virtual equilibrium hypothesis
title Visible light spectroscopic analysis of Methylene Blue in water; the resonance virtual equilibrium hypothesis
spellingShingle Visible light spectroscopic analysis of Methylene Blue in water; the resonance virtual equilibrium hypothesis
Fernández Pérez, Amparo
Methylene blue
Uv-visible spectrophotometry
Equilibrium constant
Thermo-solvatochromism
Self-aggregation
Resonance form
title_short Visible light spectroscopic analysis of Methylene Blue in water; the resonance virtual equilibrium hypothesis
title_full Visible light spectroscopic analysis of Methylene Blue in water; the resonance virtual equilibrium hypothesis
title_fullStr Visible light spectroscopic analysis of Methylene Blue in water; the resonance virtual equilibrium hypothesis
title_full_unstemmed Visible light spectroscopic analysis of Methylene Blue in water; the resonance virtual equilibrium hypothesis
title_sort Visible light spectroscopic analysis of Methylene Blue in water; the resonance virtual equilibrium hypothesis
dc.creator.none.fl_str_mv Fernández Pérez, Amparo
Valdés-Solís Iglesias, Teresa
Marbán Calzón, Gregorio
author Fernández Pérez, Amparo
author_facet Fernández Pérez, Amparo
Valdés-Solís Iglesias, Teresa
Marbán Calzón, Gregorio
author_role author
author2 Valdés-Solís Iglesias, Teresa
Marbán Calzón, Gregorio
author2_role author
author
dc.contributor.none.fl_str_mv Ministerio de Economía y Competitividad (España)
Principado de Asturias
Valdés-Solís Iglesias, Teresa [0000-0003-0822-2292]
Marbán Calzón, Gregorio [0000-0002-8387-3282]
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Methylene blue
Uv-visible spectrophotometry
Equilibrium constant
Thermo-solvatochromism
Self-aggregation
Resonance form
topic Methylene blue
Uv-visible spectrophotometry
Equilibrium constant
Thermo-solvatochromism
Self-aggregation
Resonance form
description After a critical approach to the centennial literature on Methylene Blue self-aggregation in water, accurate visible-light absorption spectra and thermodynamic equilibrium constants for the monomeric and dimeric forms of this dye in water at different temperatures were obtained by means of a novel procedure based on the Beer-Lambert equation. A thermo-solvatochromic effect was clearly detected in the monomer spectra, which we believe to be the main source of inaccuracy in all previous works. The only published explanation for this phenomenon, the existence of a colorless form of the monomer, is refuted here. Instead, a new notion has been introduced; the resonance virtual equilibrium hypothesis. According to this hypothesis the temperature-dependent absorption behavior of the monomer is provoked by the change in its electron charge distribution with the variation in the temperature-dependent dielectric constant of water. The monomer charge distribution stands between those of the virtual resonance forms, being the absorption spectrum of the monomer a composition of the theoretical spectra for the virtual mesomers, whose proportion is established by a temperature-dependent equilibrium constant. The application of this hypothesis allowed the virtual equilibrium constants and spectra for the mesomers to be evaluated with remarkable accuracy.
publishDate 2018
dc.date.none.fl_str_mv 2018
2020
2020
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Postprint
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/202469
url http://hdl.handle.net/10261/202469
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv #PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/CTM2014-56770-R
https://doi.org/10.1016/j.dyepig.2018.09.083
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
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