Synthesis and Spectrophotometric Studies of Heterocyclic Bay-Substituted Naphthalenediimide Colorimetric pH Indicators
Four naphthalenediimide colorimetric pH indicators were synthesized with <i>N</i>,<i>N</i>-dimethylethyleneamine at the imide positions and with 5- to 7-membered heterocyclic rings at the bay positions, namely pyrrolidine, morpholine, piperidine and azepane. The pH indicators...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-06-01
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| Series: | Chemosensors |
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| Online Access: | https://www.mdpi.com/2227-9040/11/7/360 |
| _version_ | 1797589848885821440 |
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| author | Filippa Magro Luke Camenzuli David C. Magri |
| author_facet | Filippa Magro Luke Camenzuli David C. Magri |
| author_sort | Filippa Magro |
| collection | DOAJ |
| description | Four naphthalenediimide colorimetric pH indicators were synthesized with <i>N</i>,<i>N</i>-dimethylethyleneamine at the imide positions and with 5- to 7-membered heterocyclic rings at the bay positions, namely pyrrolidine, morpholine, piperidine and azepane. The pH indicators are constructed in a modular <i>receptor–spacer–fluorophore–spacer–receptor</i> format based on a photoinduced electron transfer (PET) design. The compounds were studied by UV–visible absorption and steady-state fluorescence spectroscopy in 1:1 (<i>v</i>/<i>v</i>) methanol/water. Brilliant colour changes are observed between pH 2 and 4 due to an internal charge transfer (ICT) mechanism. Fluorescence <i>turn-on</i> enhancements range from 10–37 fold; however, the maximum fluorescence quantum yield in the presence of acid is <0.004, which is below naked eye detection. Hence, from the viewpoint of a human observer, these chemosensors function as colorimetric YES logic gates, and fluorimetric PASS 0 logic gates. |
| first_indexed | 2024-03-11T01:11:57Z |
| format | Article |
| id | doaj.art-b39227814e1246d5a065b4b6b93cc61c |
| institution | Directory Open Access Journal |
| issn | 2227-9040 |
| language | English |
| last_indexed | 2024-03-11T01:11:57Z |
| publishDate | 2023-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Chemosensors |
| spelling | doaj.art-b39227814e1246d5a065b4b6b93cc61c2023-11-18T18:47:12ZengMDPI AGChemosensors2227-90402023-06-0111736010.3390/chemosensors11070360Synthesis and Spectrophotometric Studies of Heterocyclic Bay-Substituted Naphthalenediimide Colorimetric pH IndicatorsFilippa Magro0Luke Camenzuli1David C. Magri2Department of Chemistry, Faculty of Science, University of Malta, MSD 2080 Msida, MaltaDepartment of Chemistry, Faculty of Science, University of Malta, MSD 2080 Msida, MaltaDepartment of Chemistry, Faculty of Science, University of Malta, MSD 2080 Msida, MaltaFour naphthalenediimide colorimetric pH indicators were synthesized with <i>N</i>,<i>N</i>-dimethylethyleneamine at the imide positions and with 5- to 7-membered heterocyclic rings at the bay positions, namely pyrrolidine, morpholine, piperidine and azepane. The pH indicators are constructed in a modular <i>receptor–spacer–fluorophore–spacer–receptor</i> format based on a photoinduced electron transfer (PET) design. The compounds were studied by UV–visible absorption and steady-state fluorescence spectroscopy in 1:1 (<i>v</i>/<i>v</i>) methanol/water. Brilliant colour changes are observed between pH 2 and 4 due to an internal charge transfer (ICT) mechanism. Fluorescence <i>turn-on</i> enhancements range from 10–37 fold; however, the maximum fluorescence quantum yield in the presence of acid is <0.004, which is below naked eye detection. Hence, from the viewpoint of a human observer, these chemosensors function as colorimetric YES logic gates, and fluorimetric PASS 0 logic gates.https://www.mdpi.com/2227-9040/11/7/360naphthalenediimideacid–base pH indicatorscolorimetricabsorbance spectroscopyinternal charge transfer |
| spellingShingle | Filippa Magro Luke Camenzuli David C. Magri Synthesis and Spectrophotometric Studies of Heterocyclic Bay-Substituted Naphthalenediimide Colorimetric pH Indicators Chemosensors naphthalenediimide acid–base pH indicators colorimetric absorbance spectroscopy internal charge transfer |
| title | Synthesis and Spectrophotometric Studies of Heterocyclic Bay-Substituted Naphthalenediimide Colorimetric pH Indicators |
| title_full | Synthesis and Spectrophotometric Studies of Heterocyclic Bay-Substituted Naphthalenediimide Colorimetric pH Indicators |
| title_fullStr | Synthesis and Spectrophotometric Studies of Heterocyclic Bay-Substituted Naphthalenediimide Colorimetric pH Indicators |
| title_full_unstemmed | Synthesis and Spectrophotometric Studies of Heterocyclic Bay-Substituted Naphthalenediimide Colorimetric pH Indicators |
| title_short | Synthesis and Spectrophotometric Studies of Heterocyclic Bay-Substituted Naphthalenediimide Colorimetric pH Indicators |
| title_sort | synthesis and spectrophotometric studies of heterocyclic bay substituted naphthalenediimide colorimetric ph indicators |
| topic | naphthalenediimide acid–base pH indicators colorimetric absorbance spectroscopy internal charge transfer |
| url | https://www.mdpi.com/2227-9040/11/7/360 |
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