Perchloro-7H-cycloprop[a]acenaphthylene and the perchlorophenalenyl system.

Coplanar neutral radicals may exhibit interesting electronic properties in the solid state. The primary obstacle to experimental test of this hypothesis is the propensity of such compounds to undergo sigma-bond coupling to form a diamagnetic dimer in the condensed state. Disulfide substitution in the coplanar phenalenyl system has been shown to suppress the dimerization reaction in the solution state, but probably not in the solid from of 1,9-dithlophenalenyl. We reasoned that perchlorination of the phenalenyl nucleus might suppress the sigma-dimerization reaction without greatly inhibiting the cofacial pi-association necessary for electronic conductivity in the solid state and wh have therefore set out to develop the synthesis and chemistry of these compounds. In the present communication we report the synthesis and characterization of perchloro-7Hcycloprop]a]acenaphthylene , and our initial entry into the perchlorophenalenyl system.