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Solubilization of Pyridone-Based Fluorescent Tag by Complexation in Cucurbit[7]uril

[Image: see text] Aimed at further exploring the hosting properties of cucurbit[7]uril (CB7), we have exploited the spectroscopic and photophysical properties of a known fluorescent label as the guest molecule, namely, 3-cyano-6-(2-thienyl)-4-trifluoromethyl pyridine (TFP), in neat solvents. The for...

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Autores principales: Alzard, Reem H., Bufaroosha, Muna S., Al-Shamsi, Noura, Sohail, Amir, Al-Dubaili, Naji, Salem, Alaa A., Abdou, Ibrahim M., Saleh, Na’il
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2019
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6648827/
https://www.ncbi.nlm.nih.gov/pubmed/31459370
http://dx.doi.org/10.1021/acsomega.8b02761
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author Alzard, Reem H.
Bufaroosha, Muna S.
Al-Shamsi, Noura
Sohail, Amir
Al-Dubaili, Naji
Salem, Alaa A.
Abdou, Ibrahim M.
Saleh, Na’il
author_facet Alzard, Reem H.
Bufaroosha, Muna S.
Al-Shamsi, Noura
Sohail, Amir
Al-Dubaili, Naji
Salem, Alaa A.
Abdou, Ibrahim M.
Saleh, Na’il
author_sort Alzard, Reem H.
collection PubMed
description [Image: see text] Aimed at further exploring the hosting properties of cucurbit[7]uril (CB7), we have exploited the spectroscopic and photophysical properties of a known fluorescent label as the guest molecule, namely, 3-cyano-6-(2-thienyl)-4-trifluoromethyl pyridine (TFP), in neat solvents. The formation of an inclusion host–guest complex with CB7 was checked by UV–vis absorption spectroscopy, and the value of binding constant (9.7 × 10(5) M(–1)) was extracted from the spectrophotometric data. The modulation of keto–enol equilibrium in TFP by the local environment is governed by the interplay between dimerization through intermolecular hydrogen bonding between individual solute molecules, favoring the enol form, and intermolecular hydrogen bonding between TFP and the surrounding solvents, favoring the keto form. Time-resolved fluorescence results established that the macromolecular CB7 host stabilizes preferentially the neutral enol form over the keto form of TFP. Unprecedentedly, our results reveal a linear dependence of the amplitudes of the extracted decay-associated spectra from the time-resolved fluorescence spectra of TFP on the sum of polarity/polarizability and hydrogen bonding parameters of the local environment, confirming that TFP at micromolar concentration in the CB7 complexes is experiencing a methanol-like environment. The results rationalized the 42-fold enhancement in the solubility of TFP in water media by complexation in CB7.
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spelling pubmed-66488272019-08-27 Solubilization of Pyridone-Based Fluorescent Tag by Complexation in Cucurbit[7]uril Alzard, Reem H. Bufaroosha, Muna S. Al-Shamsi, Noura Sohail, Amir Al-Dubaili, Naji Salem, Alaa A. Abdou, Ibrahim M. Saleh, Na’il ACS Omega [Image: see text] Aimed at further exploring the hosting properties of cucurbit[7]uril (CB7), we have exploited the spectroscopic and photophysical properties of a known fluorescent label as the guest molecule, namely, 3-cyano-6-(2-thienyl)-4-trifluoromethyl pyridine (TFP), in neat solvents. The formation of an inclusion host–guest complex with CB7 was checked by UV–vis absorption spectroscopy, and the value of binding constant (9.7 × 10(5) M(–1)) was extracted from the spectrophotometric data. The modulation of keto–enol equilibrium in TFP by the local environment is governed by the interplay between dimerization through intermolecular hydrogen bonding between individual solute molecules, favoring the enol form, and intermolecular hydrogen bonding between TFP and the surrounding solvents, favoring the keto form. Time-resolved fluorescence results established that the macromolecular CB7 host stabilizes preferentially the neutral enol form over the keto form of TFP. Unprecedentedly, our results reveal a linear dependence of the amplitudes of the extracted decay-associated spectra from the time-resolved fluorescence spectra of TFP on the sum of polarity/polarizability and hydrogen bonding parameters of the local environment, confirming that TFP at micromolar concentration in the CB7 complexes is experiencing a methanol-like environment. The results rationalized the 42-fold enhancement in the solubility of TFP in water media by complexation in CB7. American Chemical Society 2019-01-10 /pmc/articles/PMC6648827/ /pubmed/31459370 http://dx.doi.org/10.1021/acsomega.8b02761 Text en Copyright © 2019 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
spellingShingle Alzard, Reem H.
Bufaroosha, Muna S.
Al-Shamsi, Noura
Sohail, Amir
Al-Dubaili, Naji
Salem, Alaa A.
Abdou, Ibrahim M.
Saleh, Na’il
Solubilization of Pyridone-Based Fluorescent Tag by Complexation in Cucurbit[7]uril
title Solubilization of Pyridone-Based Fluorescent Tag by Complexation in Cucurbit[7]uril
title_full Solubilization of Pyridone-Based Fluorescent Tag by Complexation in Cucurbit[7]uril
title_fullStr Solubilization of Pyridone-Based Fluorescent Tag by Complexation in Cucurbit[7]uril
title_full_unstemmed Solubilization of Pyridone-Based Fluorescent Tag by Complexation in Cucurbit[7]uril
title_short Solubilization of Pyridone-Based Fluorescent Tag by Complexation in Cucurbit[7]uril
title_sort solubilization of pyridone-based fluorescent tag by complexation in cucurbit[7]uril
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6648827/
https://www.ncbi.nlm.nih.gov/pubmed/31459370
http://dx.doi.org/10.1021/acsomega.8b02761
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