Phenylnitrene singlet dynamics

Once the spectroscopy and dynamics of parent singlet phenylnitrene were understood, we began a systematic study of the effect of substitution on the kinetics of singlet phenylnitrenes. For most of the aryl azides of interest " the rate constants of singlet nitrene decay and product formation (triplet nitrene and/or ketenimine) are the same (Fig. 9). With these nitrenes, cyclization to substituted benzazirines is the rate-limiting step of the process of nitrene isomerization to ketenimine in a manner similar to the parent phenylnitrene. The only exception, o-fluorophenylnitrene, will be examined in detail in the last section of this review. 

The photochemistry of simple derivatives of 47 has also been studied in solution using product analysis and time-resolved techniques and in matrices at cryogenic temperatures using spectroscopic methods.In the last decade, a comprehensive study of the substituent effect on the reactivity of phenylnitrenes have been performed. The influence of substituents on the spectroscopy and dynamics of singlet phenylnitrene has been reviewed recently. ... 

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