Linear and radial conjugation in extended pi-electron systems.

We describe the synthesis and electronic properties of new pi-conjugated small molecules and polymers that combine the linear intramolecular conjugation pathways commonly associated with organic electronic materials with the emerging properties of radial conjugation found in cyclo(para-phenylene)s (CPPs) and other curved pi-surfaces. Using arylene ethynylenes as protypical linear segments and [6]/[8]CPP as the radial segments, we demonstrate the formation of new electronic states that are not simply additive responses from the individual components. Quantum chemical calculations of model oligomeric structures reveal these electronic processes to arise from the hybrid nature of wavefunction delocalization over the linear and radial contributors in the photophysically relevant electronic states.