The Chemiluminescent Cycloreversion of an Anthracene-Benzene Biplanemer System both in the Solid State and in the Liquid State

Article abstract of DOI:10.1246/bcsj.67.2203

In the thermal <4 + 4>cycloreversions of 9-anthracenecarboxylic acid-benzene 3a, methyl 9-anthracenecarboxylate-benzene 3b, dimethyl (or diethyl) 9,10-anthracenedicarboxylate-benzene 3c (or 3d) and anthracene-1,4-difluoro(or dichloro)benzene 3f (or 3g) biplanemers, chemiluminescence was observed for 3a-d only in the solid state at > 120 deg C but not in a liquid phase, while 3f and 3g were not chemiluminescent.Efficient chemiluminescence was observed in the photocycloreversion of all biplanemers tested in both phases.The thermodynamic parameters for the thermal cycloreversion of these biplanemers were collected.Higher activation energies were obtained in the solid state than in the liquid phase.The higher energies favor touch of the S₀ surface with the S₁ surface at the transition state for effecting the chemiluminescent cycloreversion.