TY  - JOUR
A1  - Chen, Xing
A1  - Meng, Guoyun
A1  - Liao, Guanming
A1  - Rauch, Florian
A1  - He, Jiang
A1  - Friedrich, Alexandra
A1  - Marder, Todd B.
A1  - Wang, Nan
A1  - Chen, Pangkuan
A1  - Wang, Suning
A1  - Yin, Xiaodong
T1  - Highly Emissive 9-Borafluorene Derivatives: Synthesis, Photophysical Properties and Device Fabrication
JF  - Chemistry—A European Journal
N2  - A series of 9-borafluorene derivatives, functionalised with electron-donating groups, have been prepared. Some of these 9-borafluorene compounds exhibit strong yellowish emission in solution and in the solid state with relatively high quantum yields (up to 73.6 % for FMesB-Cz as a neat film). The results suggest that the highly twisted donor groups suppress charge transfer, but the intrinsic photophysical properties of the 9-borafluorene systems remain. The new compounds showed enhanced stability towards the atmosphere, and exhibited excellent thermal stability, revealing their potential for application in materials science. Organic light-emitting diode (OLED) devices were fabricated with two of the highly emissive compounds, and they exhibited strong yellow-greenish electroluminescence, with a maximum luminance intensity of >22 000 cd m\(^{-2}\). These are the first two examples of 9-borafluorene derivatives being used as light-emitting materials in OLED devices, and they have enabled us to achieve a balance between maintaining their intrinsic properties while improving their stability.
KW  - boron heterocycles
KW  - photophysics
KW  - organic light-emitting diodes
KW  - luminescence
KW  - density functional calculations
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256738
VL  - 27
IS  - 20
ER  - 
TY  - JOUR
A1  - Rauch, Florian
A1  - Endres, Peter
A1  - Friedrich, Alexandra
A1  - Sieh, Daniel
A1  - Hähnel, Martin
A1  - Krummenacher, Ivo
A1  - Braunschweig, Holger
A1  - Finze, Maik
A1  - Ji, Lei
A1  - Marder, Todd B.
T1  - An Iterative Divergent Approach to Conjugated Starburst Borane Dendrimers
JF  - Chemistry – A European Journal
N2  - 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 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 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.
KW  - density functional calculations
KW  - electron storage
KW  - luminescence
KW  - redox
KW  - triarylborane
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218345
VL  - 26
IS  - 57
SP  - 12951
EP  - 12963
ER  -