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Spectroscopic Studies of Intramolecular Proton Transfer in 2-(4-Fluorophenylamino)-5-(2,4-Dihydroxybenzeno)-1,3,4-Thiadiazole

Spectroscopic studies of the biologically active compound 2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole (FABT), have been performed. Absorption studies in the UV-Vis region for FABT in polar solvents, like water or ethanol, exhibit the domination of the enol form over its keto c...

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Autores principales: Gagoś, Mariusz, Matwijczuk, Arkadiusz, Kamiński, Daniel, Niewiadomy, Andrzej, Kowalski, Radosław, Karwasz, Grzegorz P.
Formato: Texto
Lenguaje:English
Publicado: Springer US 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3032181/
https://www.ncbi.nlm.nih.gov/pubmed/20535632
http://dx.doi.org/10.1007/s10895-010-0682-5
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author Gagoś, Mariusz
Matwijczuk, Arkadiusz
Kamiński, Daniel
Niewiadomy, Andrzej
Kowalski, Radosław
Karwasz, Grzegorz P.
author_facet Gagoś, Mariusz
Matwijczuk, Arkadiusz
Kamiński, Daniel
Niewiadomy, Andrzej
Kowalski, Radosław
Karwasz, Grzegorz P.
author_sort Gagoś, Mariusz
collection PubMed
description Spectroscopic studies of the biologically active compound 2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole (FABT), have been performed. Absorption studies in the UV-Vis region for FABT in polar solvents, like water or ethanol, exhibit the domination of the enol form over its keto counterpart, with a broad absorption band centered around 340 nm. In non-polar solvents such as n-heptane or heavier alkanes the 340 nm absorption band disappears and an increase of the band related to the keto form (approximately 270 nm) is observed. Fluorescence spectra (with 270 nm and 340 nm excitation energies used) show a similar dependence: for FABT in 2-propanol a peak at about 400 nm dominates over that at 330 nm while in n-heptane this relation is reversed. The solvent dependent equilibrium between the keto and enol forms is further confirmed by FTIR and Raman spectroscopies. As can be expected, this equilibrium also shows some temperature dependences. We note that the changes between the two tautomeric forms of FABT are not related to the permanent dipole moment of the solvent but rather to its dipole polarizability.
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spelling pubmed-30321812011-03-16 Spectroscopic Studies of Intramolecular Proton Transfer in 2-(4-Fluorophenylamino)-5-(2,4-Dihydroxybenzeno)-1,3,4-Thiadiazole Gagoś, Mariusz Matwijczuk, Arkadiusz Kamiński, Daniel Niewiadomy, Andrzej Kowalski, Radosław Karwasz, Grzegorz P. J Fluoresc Original Paper Spectroscopic studies of the biologically active compound 2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole (FABT), have been performed. Absorption studies in the UV-Vis region for FABT in polar solvents, like water or ethanol, exhibit the domination of the enol form over its keto counterpart, with a broad absorption band centered around 340 nm. In non-polar solvents such as n-heptane or heavier alkanes the 340 nm absorption band disappears and an increase of the band related to the keto form (approximately 270 nm) is observed. Fluorescence spectra (with 270 nm and 340 nm excitation energies used) show a similar dependence: for FABT in 2-propanol a peak at about 400 nm dominates over that at 330 nm while in n-heptane this relation is reversed. The solvent dependent equilibrium between the keto and enol forms is further confirmed by FTIR and Raman spectroscopies. As can be expected, this equilibrium also shows some temperature dependences. We note that the changes between the two tautomeric forms of FABT are not related to the permanent dipole moment of the solvent but rather to its dipole polarizability. Springer US 2010-06-10 2011 /pmc/articles/PMC3032181/ /pubmed/20535632 http://dx.doi.org/10.1007/s10895-010-0682-5 Text en © The Author(s) 2010 https://creativecommons.org/licenses/by-nc/4.0/ This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
spellingShingle Original Paper
Gagoś, Mariusz
Matwijczuk, Arkadiusz
Kamiński, Daniel
Niewiadomy, Andrzej
Kowalski, Radosław
Karwasz, Grzegorz P.
Spectroscopic Studies of Intramolecular Proton Transfer in 2-(4-Fluorophenylamino)-5-(2,4-Dihydroxybenzeno)-1,3,4-Thiadiazole
title Spectroscopic Studies of Intramolecular Proton Transfer in 2-(4-Fluorophenylamino)-5-(2,4-Dihydroxybenzeno)-1,3,4-Thiadiazole
title_full Spectroscopic Studies of Intramolecular Proton Transfer in 2-(4-Fluorophenylamino)-5-(2,4-Dihydroxybenzeno)-1,3,4-Thiadiazole
title_fullStr Spectroscopic Studies of Intramolecular Proton Transfer in 2-(4-Fluorophenylamino)-5-(2,4-Dihydroxybenzeno)-1,3,4-Thiadiazole
title_full_unstemmed Spectroscopic Studies of Intramolecular Proton Transfer in 2-(4-Fluorophenylamino)-5-(2,4-Dihydroxybenzeno)-1,3,4-Thiadiazole
title_short Spectroscopic Studies of Intramolecular Proton Transfer in 2-(4-Fluorophenylamino)-5-(2,4-Dihydroxybenzeno)-1,3,4-Thiadiazole
title_sort spectroscopic studies of intramolecular proton transfer in 2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole
topic Original Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3032181/
https://www.ncbi.nlm.nih.gov/pubmed/20535632
http://dx.doi.org/10.1007/s10895-010-0682-5
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