Oligoindenopyrenes: A new class of polycyclic aromatics

A new class of polycyclic aromatic hydrocarbons-oligoindenopyrenes-has been synthesized featuring a Pd-catalyzed Suzuki-Heck coupling cascade. The oligoindenopyrenes are robust, highly colored substructures of C-70 and have properties that might prove useful in new organic materials or devices. After excitation, the tetraindenopyrene derivative 3d undergoes efficient deactivation ( 99%) by internal conversion to the ground state. The small fluorescence quantum yield ( 0.004) is in accordance with the short ( 0.6 ns) fluorescence decay time.