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Title: | Wavelength dependent regioselective E→Z isomerization of 9-anthryldiene derivatives |
Authors: | Reddy, Majjigapu Janaki Ram Kumar, Perepogu Arun Srinivas, Uppalanchi Reddy, Vummadi Venkat Reddy, Maruthi Janaki Ram Rao, G Venugopal Rao, Vaidya Jayathirtha |
Keywords: | Anthryldienes;Photoisomerization;Wavelength dependence;Regioselectivity;Charge transfer;Fluorescence |
Issue Date: | Nov-2007 |
Publisher: | CSIR |
Abstract: | 9-Anthryldiene derivatives 1-5 are synthesized to study E→Z photoisomerization. Photoisomer composition upon direct excitation, and triplet-sensitized isomerization are determined. Quantum yield of isomerization, quantum yield of fluorescence and fluorescence life times are determined for these compounds. Interestingly, upon direct excitation the anthryldiene derivatives 1-3 carrying electron withdrawing end groups (EWG) displayed wavelength dependent regioselective E→Z isomerization from the singlet excited state. Triplet sensitization studies revealed that these anthryldiene derivatives undergo Z→E isomerization and not E→Z isomerization. The dual fluorescence observed for 1, 2, 3 and 2E, 4Z-1, indicates the involvement of two different emissive states. The fluorescence solvatochromism displayed by 1, 2, 3 and 2E, 4Z-1 is a clear indication of the involvement of a highly polarized/charge transfer singlet-excited state and the same is involved in the isomerization process. Fluorescence lifetimes measured for these compounds displayed bi-exponential behavior supporting the presence of two emissive states. A mechanism for photoisomerization is suggested. |
Page(s): | 1833-1847 |
URI: | http://hdl.handle.net/123456789/710 |
ISSN: | 0376-4699 |
Appears in Collections: | IJC-B Vol.46B(11) [November 2007] |
Files in This Item:
File | Description | Size | Format | |
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IJCB 46B(11) (2007) 1833-1847.pdf | 479.75 kB | Adobe PDF | View/Open |
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