Hydrogen Abstraction by Groups Other Than the Carbonyl

HYDROGEN ABSTRACTION BY GROUPS OTHER THAN THE CARBONYL 

A number of other function groups are capable of photochemical hydrogen abstraction similar to that observed for the carbonyl. These reactions will be briefly described in this section. 

Compounds such as o-nitrotoluene which undergo photochemical reactions that are rapidly thermally reversed are called photochromic or phototropic. Nitro compounds comprise a very important group of compounds which exhibit this behavior. Further examples are as foUows  

Highly conjugated nitro derivatives are often intensely colored, making them potentially useful for information storage. 

Excitation to produce a diradical-like intermediate (excited state) can result in either hydrogen abstraction or rearrangement and closure to form the cyclobutene  

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