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Divergent Synthesis of Polyphenylene Dendrimers: The Role of Core and Branching Reagents upon Size and Shape
journal contribution
posted on 2000-12-16, 00:00 authored by U.-M. Wiesler, A. J. Berresheim, F. Morgenroth, G. Lieser, K. MüllenMonodisperse polyphenylene dendrimers up to the fourth generation were synthesized using
a divergent growth protocol. By varying the core, dendrimers with dumbbell-, tetrahedral- and propeller-like structures were synthesized. Because of the high-density packing of benzene rings within their
branches, these dendrimers are stiff and thus shape persistent. To obtain these dendrimers with a globular
shape, a 4-fold (A4B) dendrimer building unit was introduced. In this case, monodisperse dendrimers are
obtained only up to the second generation due to the significantly increased density of benzene rings
within the structure. For structure elucidation methods, like MALDI−TOF mass spectrometry, NMR
spectroscopy, GPC, VPO, TGA, and DSC were used. Dendrimers of the third and fourth generations
were visualized by transmission electron microscopy.