Kekule tautomer

They also defined a state of metaionie in which no structural formula for the so-called tautomers corresponds to the "real" structure of the reacting molecule. The Kekule forms of benzene are examples of metaionie. 74... 

Figure6.30 Illustration from a spoof issue of Berichte derDurstigen Chemischen Geseilscha/i (Berlin, 1886) showing (a) monkeys grasping one another s limbs, an image that originally inspired Kekule s structure of benzene and (b) a facetious benzene tautomer in which the monkeys are allowed to use their tails instead of their feet for bonding. The purported effect was termed a caudal residual affinity .

Fluorocarbon compounds were radiolyzed to establish the existence and assess the role of valence tautomers in radiation chemistry. Dewar-octafluorotoluene and -decafluo-roxylene have been isolated and identified as products of the photolysis and radiolysis of their respective aromatic parent in condensed phase. Dewar hexafluorobenzene was irradiated to 10 Mrad doses and found to revert to its KekulS isomer with a G-value of 10, to polymerize with G 20, and, in addition, to give rise to a new isomer. The concept of an energy sink is introduced whereby part of the energy absorbed by an aromatic system is stored in the form of interconvertible valence isomers which react further to yield polymers or decay to the ground state. 

The tautomer (1,3,5-hydroxy benzene) of this structure has two Kekule forms which are importance resonance structures. The compound will resemble benzene in being aromatic. 

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