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New routes to functionalized dihydroazulene photoswitches
| Content Provider | Semantic Scholar |
|---|---|
| Author | Nielsen, Mogens Brøndsted Broman, Søren Lindbæk Petersen, Michael Åxman Andersson, Asbjørn Sune Jensen, Tanja Skouw Kilså, Kristine Kadziola, Anders |
| Copyright Year | 2010 |
| Abstract | Molecular photoswiches are important for the development of advanced materials and molecular electronics devices. The dihydroazulene (DHA) is a particularly attractive molecule as it undergoes a light-induced ring opening to a vinylheptafulvene (VHF) isomer with altered optical properties. While functionalization of the five-membered ring of DHA has been possible for the last 25 years, this was not the case for the seven-membered ring. This article summarizes our synthetic efforts in achieving this goal. Incorporation of an alkyne at C-7 was accomplished by (i) regioselective bromination of DHA, followed by (ii) elimination of HBr, and (iii) Pd-catalyzed cross-coupling with triisopropylsilylacetylene. Light-induced ring opening of this DHA followed by thermal ring closure provided a mixture of 6- and 7-substituted DHAs with different absorption characteristics. The isomer ratio was controlled by the wavelength of irradiation and the solvent polarity. The dibromide formed in the initial step served as a precursor for a 3-bromo-functionalized azulene that was employed as a building block for acetylenic scaffolding. Incorporation of a dithiafulvene (DTF) unit at the five-membered ring of DHA resulted in a significant red-shift in the longest-wavelength absorption and consequently a lowering of the energy required for ring opening. Incorporation of a redox-active tetrathiafulvalene (TTF) unit allowed for redox-controlled photoswitching. |
| Starting Page | 843 |
| Ending Page | 852 |
| Page Count | 10 |
| File Format | PDF HTM / HTML |
| DOI | 10.1351/PAC-CON-09-07-08 |
| Alternate Webpage(s) | http://www.iupac.org/publications/pac/pdf/2010/pdf/8204x0843.pdf |
| Alternate Webpage(s) | https://doi.org/10.1351/PAC-CON-09-07-08 |
| Volume Number | 82 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
