Multiple photoluminescence from pyrene-fused hexaarylbenzenes with aggregation enhanced emission features

Multiple photoluminescence, involved in monomer emission, excimer emission and charge transfer emission origin from new pyrene-fused hexaarylbenzenes (HAB) compounds were observed, which were designed and synthesized (in high yield) via the Diels-Alder reaction of bis(2-tert-butylpyren-6-yl)acetylene and tetraphenylcyclopentadienone. Although the distinction of between two molecules arises only from the geometrical position of one of the pyrenes, the NMR spectra, the crystal packing and the physicochemical properties of these pyrene-based HAB hybrids are distinctly different both in their solution state and in aggregation-state. The X-ray diffraction analysis clearly indicated that the pyrene moieties in this system would form different crystal packing in crystal state that can induce a fantastic multiple photoluminescence phenomenon.