Double homologation method for substituted soluble pentacenes and dimerization behaviours of pentacenes.

Double up: A zirconium-mediated double homologation method was successfully applied for the synthesis of multi-substituted pentacene derivatives from 1,2,4,5-tetrakis(propargyl)benzenes. The bis(zirconacyclopentadiene) intermediates were also characterized. Among these symmetrical derivatives, tetra- and octa-substituted pentacenes undergo reversible conversion between monomeric and dimeric forms. A double homologation method for the formation of substituted soluble pentacenes was developed by a zirconium-mediated cyclization of tetrayne derivatives. Thermal dimerization of tetra- and octasubstituted pentacenes was observed. The dimerization behavior was observed to be strongly related to the substituent groups affixed to the pentacenes.