Gitendra C. Paul

Photolysis of chloride precursors as a method to prepare and characterize the triplet state of fluorenyl-substituted m-xylylene diradicals

Fluorenyl substituted m-xylylene triplet diradicals are conveniently generated from the corresponding dichloride precursors upon photolysis at <100 K in 2-MeTHF glass. Under similar conditions tert-butyl substituted Schlenk type m-xylylene could not be generated from the dichloride precursor 6. Compound 6, however could be dehalogenated with zinc dust in both toluene and 2-MeTHF to produce the triplet diradical.

Possible reversible intersystem crossing in a geminal biscyclopropyl substituted m-xylylene

Abstract Reaction of 6,6-dicyclopropylfulvene with isobutylidene gives rise to products derived from a m-xylylene. Both cyclopropane ring opened monomers with o- and p-isocumene-like structures and dimers with intact cyclopropane rings are formed. Since m-xylylene would appear to be a relatively stable triplet and would not be expected to give cyclopropane ring opened monomeric products, it is suggested that steric effects retard the formation of dimers from the triplet state thereby allowing ring opening to occur out of the singlet state.