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The synthesis and thermal and photochemical degradation of alkyl- and arylazidofluorenes

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dc.contributor.advisor Taljaard B, Dr en
dc.contributor.author Burger GJ en
dc.date.accessioned 2016-09-22T13:19:03Z
dc.date.available 2016-09-22T13:19:03Z
dc.date.submitted 1991 en
dc.identifier.uri http://hdl.handle.net/20.500.11892/157520
dc.description.abstract The synthesis and thermal and photochemical degradations of 9- alkyl- and 9-arylfluorenes were investigated. Due to their thermal instability, 9-alkyl-9-azidofluorenes decomposed on attempted synthesis, whereas 9-aryl-9-azidofluorenes decomposed smoothly at temperatures >190°C to give good yields of 6- arylphenanthridines, with small amounts of 9-N-arylfluorenimines as ancillary products. The photochemical degradation of this class of azides in various solvents gave similar results. Photolysis of 9-azido-9-phenylfluorene in the cavity of an e.p.r. spectrometer gave the 9-phenylfluorene radical due to 9-carbon- nitrogen bond fission, suggesting a parallel free radical pathway in the decomposition pathway. As a result of the small substituent effects on the relative migratory aptitudes, a very reactive common intermediate is postulated for photochemical degradations. In contrast, thermolysis of the azides showed large variations of the relative migratory aptitudes, suggesting a polar transition state. Although reactive intermediates in the reactions could not be trapped on decomposition in the presence of various alkenes, preliminary spectroscopic evidence could be obtained for cycloaddition of 9-azido-9-phenylfluorene to norbornene. It is thus proposed that the intramolecular rearrangement of these very stable azides occur at a much higher rate than intermolecular reactions with double bonds. en
dc.language English en
dc.title The synthesis and thermal and photochemical degradation of alkyl- and arylazidofluorenes en
dc.type Masters degree en
dc.description.degree MSc en

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