An Iterative Divergent Approach to Conjugated Starburst Borane Dendrimers |
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Authors: | Dr Florian Rauch Peter Endres Dr Alexandra Friedrich Dr Daniel Sieh Dr Martin Hähnel Dr Ivo Krummenacher Prof Dr Holger Braunschweig Prof Dr Maik Finze Prof Dr Lei Ji Prof Dr Todd B Marder |
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Institution: | Institut für Anorganische Chemie and Institute for Sustainable Chemistry &, Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany |
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Abstract: | Using a new divergent approach, conjugated triarylborane dendrimers were synthesized up to the 2nd generation. The synthetic strategy consists of three steps: 1) functionalization, via iridium catalyzed C−H borylation; 2) activation, via fluorination of the generated boronate ester with KHF2] or N(nBu4)]HF2]; and 3) expansion, via reaction of the trifluoroborate salts with aryl Grignard reagents. The concept was also shown to be viable for a convergent approach. All but one of the conjugated borane dendrimers exhibit multiple, distinct and reversible reduction potentials, making them potentially interesting materials for applications in molecular accumulators. Based on their photophysical properties, the 1st generation dendrimers exhibit good conjugation over the whole system. However, the conjugation does not increase further upon expansion to the 2nd generation, but the molar extinction coefficients increase linearly with the number of triarylborane subunits, suggesting a potential application as photonic antennas. |
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Keywords: | density functional calculations electron storage luminescence redox triarylborane |
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