A Desirable Route to Heterodimers of 1,4-Dihalobenzenes and Anthracene and Their Photoproperties and Thermal Properties

Electronic oxidative bisdecarboxylation of photoadducts of 2,5-dihalo-1,2-dihydrophthalic anhydride and anthracene gave the corresponding energy-rich heterodimers 12 and 13. The quantum yields of the formation of the excited anthracene from 12 and 13 by the irradiation of 280-nm light were 0.65 and 0.25, respectively. We assumed that the heterodimers of 12 and 13 form biradicaloid intermediates during thermal retro [4πs + 4πs] cycloaddition and consumed their stored energy without any visible light. However, we observed emission light from 340 to 460 nm through a glass filter and the formation of anthracene using Nd-YAG laser IR light (1.06 μm) by the multiphoton absorption, when fine powders of 12 and 13 were used.