An Iterative Divergent Approach to Conjugated Starburst Borane Dendrimers. Issue 57 (16th September 2020)

• Record Type: Journal Article
• Authors: Rauch, Florian; Endres, Peter; Friedrich, Alexandra; Sieh, Daniel; Hähnel, Martin; Krummenacher, Ivo; Braunschweig, Holger; Finze, Maik; Ji, Lei; Marder, Todd B.
• Is Part Of: Chemistry. Volume 26:Issue 57(2020)
• Page Start: 12951
• Page End: 12963
• Publication Date: 2020-09-16
• Subjects: density functional calculations -- electron storage -- luminescence -- redox -- triarylborane; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202001985
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Using a new divergent approach, conjugated triarylborane dendrimers were synthesized up to the 2 nd 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 K[HF2 ] 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 1 st generation dendrimers exhibit good conjugation over the whole system. However, the conjugation does not increase further upon expansion to the 2 nd generation, but the molar extinction coefficients increase linearly with the number of triarylborane subunits, suggesting a potential application as photonic antennas. Abstract : Boron branches out : Conjugated starburst borane dendrimers were synthesized up to the 2 nd generation, using to a new, divergent, three‐step approach, exhibiting good substrate tolerance. The dendrimers exhibit multiple, distinct and reversible reduction potentials, making them potential materials for molecular accumulators. Photophysical measurements indicate good conjugation up to the 1 st generation.