title: Multichromophoric polyphenylene dendrimers: toward brilliant light emitters with an increased number of fluorophores.
abstract: Two routes for the introduction of highly fluorescent peryleneimide chromophores into the scaffolding of polyphenylene dendrimers via iterative Diels-Alder cycloadditions are presented. The key intermediates for the divergent dendrimer buildup were two cyclopentadienone branching units carrying two peryleneimides and two masked terminal alkynes. The difference between the two reagents is the mode of incorporation of the chromophores. In the first case, the chromophores were attached to the alpha-position of the tetraphenylcyclopentadienones. In the second case, peryleneimides are used as a "spacer" in the beta-position of the cyclopentadienones giving rise to dendrimers with extended molecular diameters (up to 12 nm) and 24 chromophores within their scaffold. Absorption and emission characteristics of the new multichromophoric nanoparticles were investigated and compared to those of the parent dyes. Additionally, an asymmetrically substituted first-generation dendrimer with six perylene diimide chromophores and one ester functionality is reported. The ester serves as a potential anchor group, and this nanoemitter paves the way to a multichromophoric fluorescence label. All dendrimers have good solubility in common organic solvents, high fluorescence quantum yields, and defined distances between the chromophores, making them attractive candidates for single-molecule spectroscopy.
authors: Max-Planck-Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany.
authors: Ingo
authors: I
authors: Oesterling
authors: Klaus
authors: K
authors: Müllen
mesh_terms: D003198:Computer Simulation; D003517:Cyclopentanes / Q000737:chemistry; D050091:Dendrimers / Q000737:chemistry*; D008027:Light; D008958:Models, Molecular; D015394:Molecular Structure; D008970:Molecular Weight; D011108:Polymers / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013057:Spectrum Analysis
chemical_list: D003517:Cyclopentanes; D050091:Dendrimers; D011108:Polymers; C009440:tetraphenylcyclopentadienone; C041325:polyphenylene sulfide