Polyphenylene dendrimers with perylene diimide as a luminescent core

A novel synthesis is presented of a fourfold ethynyl-substituted perylene d iimide dye 4, which acts as a core molecule for the buildup of polyphenylen e dendrimers. Around the luminescent core 4. a first-generation (5). a seco nd-generation (6), and a third-generation (7) polyphenylene dendritic envir onment consisting of pentaphenylbenzene building blocks are constructed. Th e dendrimers 5 and 6 are synthesized by an exclusively divergent route, whe reas for 7, a combination of a divergent and convergent approaches is appli ed. Absorption and emission spectra of 5-7 in different solvents and in a f ilm have been measured and compared to a nondendronized model compound 13. In solution, the internal chromophore is scarcely influenced by the dendrit ic scaffold. however, in the solid state, aggregation of the perylene diimi de is prevented very effectively by the four rigid dendrons. Additionally, fluorescence quantum yields in solution have been determined for 5-7 and 13 ; they decrease as the number of generation increases.