pH-sensitive fluorescence switching of pyridylanthracenes
- 9,10-substituted anthracenes are known for their useful optical properties like fluorescence, which makes them frequently used probes in sensing applications. In this article, we investigate the fundamental photophysical properties of three pyridyl-substituted variants. The nitrogen atoms in the pyridinium six-membered rings are located in the ortho-, meta-, and para-positions in relation to the anthracene core. Absorption, fluorescence, and transient absorption measurements were carried out and were complemented by theoretical calculations. We monitored the photophysics of the anthracene derivatives in chloroform and water investigating the protonated as well as their nonprotonated forms. We found that the optical properties of the nonprotonated forms are strongly determined by the anthracene chromophore, with only small differences to other 9,10-substituted anthracenes, for example diphenyl anthracene. In contrast, protonation leads to a strong decrease in fluorescence intensity and lifetime. Transient absorption measurements and9,10-substituted anthracenes are known for their useful optical properties like fluorescence, which makes them frequently used probes in sensing applications. In this article, we investigate the fundamental photophysical properties of three pyridyl-substituted variants. The nitrogen atoms in the pyridinium six-membered rings are located in the ortho-, meta-, and para-positions in relation to the anthracene core. Absorption, fluorescence, and transient absorption measurements were carried out and were complemented by theoretical calculations. We monitored the photophysics of the anthracene derivatives in chloroform and water investigating the protonated as well as their nonprotonated forms. We found that the optical properties of the nonprotonated forms are strongly determined by the anthracene chromophore, with only small differences to other 9,10-substituted anthracenes, for example diphenyl anthracene. In contrast, protonation leads to a strong decrease in fluorescence intensity and lifetime. Transient absorption measurements and theoretical calculations revealed the formation of a charge-transfer state in the protonated chromophores, where electron density is shifted from the anthracene moiety toward the protonated pyridyl substituents. While the para- and ortho-derivatives' charge transfer is still moderately fluorescent, the meta-derivative is affected much stronger and shows nearly no fluorescence. This nitrogen-atom-position-dependent sensitivity to hydronium activity makes a combination of these fluorophores very attractive for pH-sensing applications covering a broadened pH range.…
Author details: | Toni HaubitzORCiDGND, Werner FudickarORCiDGND, Torsten LinkerORCiDGND, Michael Uwe KumkeORCiDGND |
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DOI: | https://doi.org/10.1021/acs.jpca.0c09911 |
ISSN: | 1089-5639 |
ISSN: | 1520-5215 |
Pubmed ID: | https://pubmed.ncbi.nlm.nih.gov/33337145 |
Title of parent work (English): | The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment & general theory |
Subtitle (English): | the effect of the isomeric pattern |
Publisher: | American Chemical Society |
Place of publishing: | Washington |
Publication type: | Article |
Language: | English |
Date of first publication: | 2020/12/18 |
Publication year: | 2020 |
Release date: | 2022/11/28 |
Tag: | Absorption; Aromatic compounds; Fluorescence; Hydrocarbons; Reaction mechanisms |
Volume: | 124 |
Issue: | 52 |
Number of pages: | 8 |
First page: | 11017 |
Last Page: | 11024 |
Funding institution: | Federal Ministry for Economic Affairs and Energy [02E11415F] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften | |
Peer review: | Referiert |