Series of TEMPO-substituted norbornadiene, spiropyran and anthracene derivatives have been prepared; their light-induced structural change to the corresponding qudricyclanes. merocyanines or anthracene-dimers and the reverse reactions to the starting materials have been studied. The antiferromagnetic or ferromagnetic behavior observed in norbornadienes/anthracenes was found to be preserved in the corresponding quadricyclanes/anthracene-dimers in spite of the difference of their Weiss temperatures, whereas switching of the intermolecular magnetic interactions was observed in spiropyran/merocyanine systems.
Nakatsuji, Shin'ichi; Ogawa, Yuya; Takeuchi, Soichi, Journal of the Chemical Society. Perkin Transactions 2 (2001), 2000, # 9, p. 1969 - 1975