An internal charge transfer-dependent solvent effect in V-shaped azacyanines
- New V-shaped non-centrosymmetric dyes, possessing a strongly electron-deficient azacyanine core, have been synthesized based on a straightforward two-step approach. The key step in this synthesis involves palladium-catalysed cross-coupling of dibromo-N,N′-methylene-2,2′-azapyridinocyanines with arylacetylenes. The resulting strongly polarized π-expanded heterocycles exhibit green to orange fluorescence and they strongly respond to changes in solvent polarity. We demonstrate that differently electron-donating peripheral groups have a significant influence on the internal charge transfer, hence on the solvent effect and fluorescence quantum yield. TD-DFT calculations confirm that, in contrast to the previously studied bis(styryl)azacyanines, the proximity of S1 and T2 states calculated for compounds bearing two 4-N,N-dimethylaminophenylethynyl moieties establishes good conditions for efficient intersystem crossing and is responsible for its low fluorescence quantum yield. Non-linear properties have also been determined for newNew V-shaped non-centrosymmetric dyes, possessing a strongly electron-deficient azacyanine core, have been synthesized based on a straightforward two-step approach. The key step in this synthesis involves palladium-catalysed cross-coupling of dibromo-N,N′-methylene-2,2′-azapyridinocyanines with arylacetylenes. The resulting strongly polarized π-expanded heterocycles exhibit green to orange fluorescence and they strongly respond to changes in solvent polarity. We demonstrate that differently electron-donating peripheral groups have a significant influence on the internal charge transfer, hence on the solvent effect and fluorescence quantum yield. TD-DFT calculations confirm that, in contrast to the previously studied bis(styryl)azacyanines, the proximity of S1 and T2 states calculated for compounds bearing two 4-N,N-dimethylaminophenylethynyl moieties establishes good conditions for efficient intersystem crossing and is responsible for its low fluorescence quantum yield. Non-linear properties have also been determined for new azacyanines and the results show that depending on peripheral groups, the synthesized dyes exhibit small to large two-photon absorption cross sections reaching 4000 GM.…
Author details: | Mariusz Tasior, Ilko BaldORCiDGND, Irena Deperasińska, Piotr J. Cywiński, Daniel T. Gryko |
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URN: | urn:nbn:de:kobv:517-opus4-102704 |
Publication series (Volume number): | Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe (306) |
Publication type: | Postprint |
Language: | English |
Date of first publication: | 2015/10/08 |
Publication year: | 2015 |
Publishing institution: | Universität Potsdam |
Release date: | 2017/02/03 |
First page: | 11714 |
Last Page: | 11720 |
Source: | Org. Biomol. Chem. (2015) Nr. 13, S. 11714-11720. - DOI: 10.1039/c5ob01633a |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
Peer review: | Referiert |
Publishing method: | Open Access |
License (German): | Keine öffentliche Lizenz: Unter Urheberrechtsschutz |