Anthrylmethyl radical

Bond cleavage from excited radicals has also been observed in a laser jet study of the fc/s-ether (219). Thus, the excited 9-anthrylmethyl radical is suggested to undergo loss of phenoxy radical to yield the 9,10-bis-anthrylmethyl biradical (Scheme 13). This is a three-photon process, with two photons required to produce the monoradical and an additional photon needed to generate the biradical. The authors note that the biradical itself may have photochemistry, forming the 9,10-bis-methylether (220) upon further photolysis in methanol [132]. 

In the case of dissociation of the various methyl-substituted anthracenes to form the corresponding anthrylmethyl radicals the relative magnitude of the interaction between the a orbitals of the characteristic configuration and the n and Jt orbitals involved in the excitation may be estimated quite easily. Assuming that the interaction is proportional to the square of the LUMO coefficient of the carbon atom adjacent to the methyl group, the lowest barrier is expected for the 9-methyl derivative and the highest one for the 2-methyl derivative. as may be seen from the squared coefficients given in formula 55. 

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