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An Iterative Divergent Approach to Conjugated Starburst Borane Dendrimers
Author(s) -
Rauch Florian,
Endres Peter,
Friedrich Alexandra,
Sieh Daniel,
Hähnel Martin,
Krummenacher Ivo,
Braunschweig Holger,
Finze Maik,
Ji Lei,
Marder Todd B.
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202001985
Subject(s) - dendrimer , borane , borylation , conjugated system , reagent , chemistry , combinatorial chemistry , aryl , conjugate , organic chemistry , catalysis , polymer , alkyl , mathematics , mathematical analysis
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[HF 2 ] or [N(nBu 4 )][HF 2 ]; 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.