Asymmetric Donor–Acceptor 2,7-Disubstituted Fluorenes and Their 9-Diazoderivatives: Synthesis, Optical Spectra and Photolysis
In a search for dyes photoactivatable with visible light, fluorenes with substituents at positions 2 and 7 were prepared, and their absorption and emission spectra were studied. In particular, the synthesis route to 9-diazofluorenes with 2-(N,N-dialkylamino) and N-modified 7-(4-pyridyl) substituents...
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2025-01-01
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| author | Andrei I. Savchenko Vladimir N. Belov Mariano L. Bossi Stefan W. Hell |
| author_facet | Andrei I. Savchenko Vladimir N. Belov Mariano L. Bossi Stefan W. Hell |
| author_sort | Andrei I. Savchenko |
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| description | In a search for dyes photoactivatable with visible light, fluorenes with substituents at positions 2 and 7 were prepared, and their absorption and emission spectra were studied. In particular, the synthesis route to 9-diazofluorenes with 2-(N,N-dialkylamino) and N-modified 7-(4-pyridyl) substituents was established. These compounds are initially non-fluorescent, undergo photolysis with UV or blue light, and—in non-polar media—provide orange- to red-emitting products with a large separation between absorption and emission bands. Irradiation of non-fluorescent 9-diazoderivative <b>20</b> in dioxane with the light of 365 nm or 470 nm was accompanied by strong fluorescence gain (10 to 20 times), orange–red emission, and a large Stokes shift of photoproducts, which structurally relate to fluorescent betaine <b>13</b> (model compound without diazo group). Photolysis of <b>20</b> in protic solvents (ROH = MeOH, H<sub>2</sub>O) provided clean transformation to C<sup>9</sup>-OR derivatives, though the emission gain in protic solvents was low. |
| format | Article |
| id | doaj-art-5d04996ebde94c11882f5accfefbe43e |
| institution | Kabale University |
| issn | 1420-3049 |
| language | English |
| publishDate | 2025-01-01 |
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| series | Molecules |
| spelling | doaj-art-5d04996ebde94c11882f5accfefbe43e2025-01-24T13:43:35ZengMDPI AGMolecules1420-30492025-01-0130232110.3390/molecules30020321Asymmetric Donor–Acceptor 2,7-Disubstituted Fluorenes and Their 9-Diazoderivatives: Synthesis, Optical Spectra and PhotolysisAndrei I. Savchenko0Vladimir N. Belov1Mariano L. Bossi2Stefan W. Hell3Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences (MPI-NAT), Am Fassberg 11, 37077 Göttingen, GermanyDepartment of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences (MPI-NAT), Am Fassberg 11, 37077 Göttingen, GermanyDepartment of Optical Nanoscopy, Max Planck Institute for Medical Research (MPI-MR), Jahnstraße 29, 69120 Heidelberg, GermanyDepartment of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences (MPI-NAT), Am Fassberg 11, 37077 Göttingen, GermanyIn a search for dyes photoactivatable with visible light, fluorenes with substituents at positions 2 and 7 were prepared, and their absorption and emission spectra were studied. In particular, the synthesis route to 9-diazofluorenes with 2-(N,N-dialkylamino) and N-modified 7-(4-pyridyl) substituents was established. These compounds are initially non-fluorescent, undergo photolysis with UV or blue light, and—in non-polar media—provide orange- to red-emitting products with a large separation between absorption and emission bands. Irradiation of non-fluorescent 9-diazoderivative <b>20</b> in dioxane with the light of 365 nm or 470 nm was accompanied by strong fluorescence gain (10 to 20 times), orange–red emission, and a large Stokes shift of photoproducts, which structurally relate to fluorescent betaine <b>13</b> (model compound without diazo group). Photolysis of <b>20</b> in protic solvents (ROH = MeOH, H<sub>2</sub>O) provided clean transformation to C<sup>9</sup>-OR derivatives, though the emission gain in protic solvents was low.https://www.mdpi.com/1420-3049/30/2/321fluorescencephotoactivationorganic synthesisdiazo compoundsfluorenes |
| spellingShingle | Andrei I. Savchenko Vladimir N. Belov Mariano L. Bossi Stefan W. Hell Asymmetric Donor–Acceptor 2,7-Disubstituted Fluorenes and Their 9-Diazoderivatives: Synthesis, Optical Spectra and Photolysis Molecules fluorescence photoactivation organic synthesis diazo compounds fluorenes |
| title | Asymmetric Donor–Acceptor 2,7-Disubstituted Fluorenes and Their 9-Diazoderivatives: Synthesis, Optical Spectra and Photolysis |
| title_full | Asymmetric Donor–Acceptor 2,7-Disubstituted Fluorenes and Their 9-Diazoderivatives: Synthesis, Optical Spectra and Photolysis |
| title_fullStr | Asymmetric Donor–Acceptor 2,7-Disubstituted Fluorenes and Their 9-Diazoderivatives: Synthesis, Optical Spectra and Photolysis |
| title_full_unstemmed | Asymmetric Donor–Acceptor 2,7-Disubstituted Fluorenes and Their 9-Diazoderivatives: Synthesis, Optical Spectra and Photolysis |
| title_short | Asymmetric Donor–Acceptor 2,7-Disubstituted Fluorenes and Their 9-Diazoderivatives: Synthesis, Optical Spectra and Photolysis |
| title_sort | asymmetric donor acceptor 2 7 disubstituted fluorenes and their 9 diazoderivatives synthesis optical spectra and photolysis |
| topic | fluorescence photoactivation organic synthesis diazo compounds fluorenes |
| url | https://www.mdpi.com/1420-3049/30/2/321 |
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