Dendritic polyphenylene framework as a light-harvesting shell for highly emissive [2.2]Paracyclophane core

Abstract New polyphenylene type dendrimers of two generations were developed through attaching the aromatic dendron units to the highly emissive conjugated 4,7,12,15-tetra(phenylethynyl)[2.2]paracyclophane core via the Diels-Alder reaction. The polyphenylene moieties in dendrimers efficiently absorbed the UV light, followed by the energy transfer to the [2.2]paracyclophane core, resulting in photoluminescence with high quantum yields from the core unit and demonstrating efficient intramolecular energy transfer. The detailed analysis of optical properties of polyphenylene dendrimers with the [2.2]paracyclophane core was carried out using parent model compounds that resemble the constituents of respective dendrimers. The success of this study became possible to a certain extent due to an improvement of the synthetic procedure for 4,7,12,15-tetraethynyl substituted [2.2]paracyclophane derivatives allowing for high yields of target products.