Synthesis and fluorescence studies of selected N-aryl-2-aminoquinolines: Effect of hydrogen bonding, substituents and ESIPT on their fluorescence quantum yields

N-aryl-2-aminoquinolines have been widely synthesised and used in biological applications. However, their luminescence properties have not been studied in detail. Herein a series of N-aryl-2-aminoquinolines was synthesised from substitution reaction between 2-chloroquinoline and anilines with differ...

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Main Authors: Hisham, Shameer, Tajuddin, Hairul Anuar, Chee, Chin Fei, Hasan, Zainal Abidin, Abdullah, Zanariah
Format: Article
Published: Elsevier 2019
Subjects:
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author Hisham, Shameer
Tajuddin, Hairul Anuar
Chee, Chin Fei
Hasan, Zainal Abidin
Abdullah, Zanariah
author_facet Hisham, Shameer
Tajuddin, Hairul Anuar
Chee, Chin Fei
Hasan, Zainal Abidin
Abdullah, Zanariah
author_sort Hisham, Shameer
collection UM
description N-aryl-2-aminoquinolines have been widely synthesised and used in biological applications. However, their luminescence properties have not been studied in detail. Herein a series of N-aryl-2-aminoquinolines was synthesised from substitution reaction between 2-chloroquinoline and anilines with different substituent groups gave sufficient yield from 72–90%. The fluorescence behaviour was investigated in toluene, ethyl acetate and ethanol. The result shows that fluorescence quantum yield of N-aryl-2-aminoquinolines was the highest in toluene, followed by in ethyl acetate and the lowest in ethanol. Quenched emission observed in ethanol is caused by site-specific fluorophore-solvent hydrogen bonding interactions, inducing deactivation of the quinolinyl ring system. The bell-shaped Hammett plot of various substituted compounds suggested that both strong electron donating and electron withdrawing groups caused significant quenching in the fluorescence quantum yields. Therefore, most types of substituent groups on the phenyl moiety, hydrogen bonding between the fluorophore and solvent, and excited-state intramolecular proton transfer (ESIPT) were found as crucial contributors to fluorescence quenching of N-aryl-2-aminoquinolines.
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spelling um.eprints-200722019-01-22T01:41:08Z http://eprints.um.edu.my/20072/ Synthesis and fluorescence studies of selected N-aryl-2-aminoquinolines: Effect of hydrogen bonding, substituents and ESIPT on their fluorescence quantum yields Hisham, Shameer Tajuddin, Hairul Anuar Chee, Chin Fei Hasan, Zainal Abidin Abdullah, Zanariah Q Science (General) QD Chemistry N-aryl-2-aminoquinolines have been widely synthesised and used in biological applications. However, their luminescence properties have not been studied in detail. Herein a series of N-aryl-2-aminoquinolines was synthesised from substitution reaction between 2-chloroquinoline and anilines with different substituent groups gave sufficient yield from 72–90%. The fluorescence behaviour was investigated in toluene, ethyl acetate and ethanol. The result shows that fluorescence quantum yield of N-aryl-2-aminoquinolines was the highest in toluene, followed by in ethyl acetate and the lowest in ethanol. Quenched emission observed in ethanol is caused by site-specific fluorophore-solvent hydrogen bonding interactions, inducing deactivation of the quinolinyl ring system. The bell-shaped Hammett plot of various substituted compounds suggested that both strong electron donating and electron withdrawing groups caused significant quenching in the fluorescence quantum yields. Therefore, most types of substituent groups on the phenyl moiety, hydrogen bonding between the fluorophore and solvent, and excited-state intramolecular proton transfer (ESIPT) were found as crucial contributors to fluorescence quenching of N-aryl-2-aminoquinolines. Elsevier 2019 Article PeerReviewed Hisham, Shameer and Tajuddin, Hairul Anuar and Chee, Chin Fei and Hasan, Zainal Abidin and Abdullah, Zanariah (2019) Synthesis and fluorescence studies of selected N-aryl-2-aminoquinolines: Effect of hydrogen bonding, substituents and ESIPT on their fluorescence quantum yields. Journal of Luminescence, 208. pp. 245-252. ISSN 0022-2313, DOI https://doi.org/10.1016/j.jlumin.2018.12.059 <https://doi.org/10.1016/j.jlumin.2018.12.059>. https://doi.org/10.1016/j.jlumin.2018.12.059 doi:10.1016/j.jlumin.2018.12.059
spellingShingle Q Science (General)
QD Chemistry
Hisham, Shameer
Tajuddin, Hairul Anuar
Chee, Chin Fei
Hasan, Zainal Abidin
Abdullah, Zanariah
Synthesis and fluorescence studies of selected N-aryl-2-aminoquinolines: Effect of hydrogen bonding, substituents and ESIPT on their fluorescence quantum yields
title Synthesis and fluorescence studies of selected N-aryl-2-aminoquinolines: Effect of hydrogen bonding, substituents and ESIPT on their fluorescence quantum yields
title_full Synthesis and fluorescence studies of selected N-aryl-2-aminoquinolines: Effect of hydrogen bonding, substituents and ESIPT on their fluorescence quantum yields
title_fullStr Synthesis and fluorescence studies of selected N-aryl-2-aminoquinolines: Effect of hydrogen bonding, substituents and ESIPT on their fluorescence quantum yields
title_full_unstemmed Synthesis and fluorescence studies of selected N-aryl-2-aminoquinolines: Effect of hydrogen bonding, substituents and ESIPT on their fluorescence quantum yields
title_short Synthesis and fluorescence studies of selected N-aryl-2-aminoquinolines: Effect of hydrogen bonding, substituents and ESIPT on their fluorescence quantum yields
title_sort synthesis and fluorescence studies of selected n aryl 2 aminoquinolines effect of hydrogen bonding substituents and esipt on their fluorescence quantum yields
topic Q Science (General)
QD Chemistry
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