FISCHER, C and DAUB, J (1993) CROWN ETHER-BEARING DIHYDROAZULENES - SYNTHESIS AND PHOTOCHROMISM OF A BENZO[15]CROWN-5 DERIVATIVE. CHEMISCHE BERICHTE-RECUEIL, 126 (7). pp. 1631-1634. ISSN 0009-2940,
Full text not available from this repository.Abstract
Photosensitive crown ether 1 composed of 1,8a-dihydroazulene as a photodynamic unit and a benzo[15]crown-5 ether subgroup has been synthesized from C-7-substituted cycloheptatriene 8, which has been obtained by nucleophilic addition of 4-acetylbenzo[15]crown-5 (6) to tropenylium tetrafluoroborate (7). Dehydrogenation of dicyanovinyl derivative 9 leads to heptdfulvene 2 which thermally rearranges to dihydroazulene 1. Attempts to synthesize 1 according to the ''[8 + 2]-cycloaddition route'' have been unsuccessful. Crown ether 1 shows photochromic bistability with a photochemically driven forward and a thermal back reaction. The spectroscopic properties of 1 and the photochemical isomerization 1 --> 2 have been shown to be almost insensitive to sodium iodide addition. The rate of the thermal back reaction 2 --> 1 slightly is affected by sodium iodide addition.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ELECTRON-RICH HEPTAFULVENES; INVERSE RING-POLARIZATION; FULVENES; PHOTOCHROMISM; PHOTORESPONSIVE CROWN ETHER |
| Depositing User: | Dr. Gernot Deinzer |
| Last Modified: | 19 Oct 2022 08:42 |
| URI: | https://pred.uni-regensburg.de/id/eprint/53889 |
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