Convenient Unimolecular Sources of Aryloxyl Radicals II-Aryloxyoxaly tert-Butylperoxides.

摘要

The UV photolysis and mild condition thermolysis (70 C) of aryloxyoxalyl tert-butlperoxides (AOB's) provides a new unimolecular source of aryloxyl radicals, as shown by ESR and UV-vis spectroscopy. The species studied were used to generate known, sterically stabilized phenoxyl radicals for ESR comparisons. Comparison of known spectra with those generated by our method was good. The thermal stability of the AOB's is apparently inferior to that of the related aryloxyoxalyl chlorides (AOC's), but the AOC's are more environment sensitive (hydrolysis, etc.). Occasional reaction of decomposition fragments to give undesired paramagnetic side products was observed in one case. Decomposition of the AOB's is readily monitored by proton NMR spectroscopy, when stable radicals are not generated. Keywords: Unimolecular photochemical; Thermal generation; Phenoxyl radicals; Acoustic optics. (jes)