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Highly Stable, Readily Reducible, Fluorescent, Trifluoromethylated 9‐Borafluorenes
- Source :
- Chemistry (Weinheim an Der Bergstrasse, Germany)
- Publication Year :
- 2020
- Publisher :
- Wiley, 2020.
-
Abstract
- Three different perfluoroalkylated borafluorenes (F Bf) were prepared and their electronic and photophysical properties were investigated. The systems have four trifluoromethyl moieties on the borafluorene moiety as well as two trifluoromethyl groups at the ortho positions of their exo‐aryl moieties. They differ with regard to the para substituents on their exo‐aryl moieties, being a proton (F XylFBf, FXyl: 2,6‐bis(trifluoromethyl)phenyl), a trifluoromethyl group (F MesFBf, FMes: 2,4,6‐tris(trifluoromethyl)phenyl) or a dimethylamino group (p ‐NMe2‐FXylFBf, p‐NMe2‐FXyl: 4‐(dimethylamino)‐2,6‐bis(trifluoromethyl)phenyl), respectively. All derivatives exhibit extraordinarily low reduction potentials, comparable to those of perylenediimides. The most electron‐deficient derivative F MesFBf was also chemically reduced and its radical anion isolated and characterized. Furthermore, all compounds exhibit very long fluorescent lifetimes of about 250 ns up to 1.6 μs; however, the underlying mechanisms responsible for this differ. The donor‐substituted derivative p ‐NMe2‐FXylFBf exhibits thermally activated delayed fluorescence (TADF) from a charge‐transfer (CT) state, whereas the F MesFBf and F XylFBf borafluorenes exhibit only weakly allowed locally excited (LE) transitions due to their symmetry and low transition‐dipole moments.<br />Having your cake and eating it too: Functionalization of 9‐borafluorenes with trifluoromethyl groups makes them exceptionally easy to reduce while maintaining excellent stability towards hydrolysis. The systems also exhibit long‐lived fluorescence or thermally activated delayed fluorescence (TADF) depending on the exo‐aryl para‐substituent.
- Subjects :
- Proton
Dibenzoborole
010402 general chemistry
01 natural sciences
Catalysis
law.invention
chemistry.chemical_compound
law
Borafluorenes | Very Important Paper
Moiety
Electron paramagnetic resonance
heterocycles
Trifluoromethyl
Full Paper
010405 organic chemistry
Chemistry
Organic Chemistry
General Chemistry
Full Papers
Fluorescence
0104 chemical sciences
borafluorenes
Crystallography
Excited state
ddc:540
fluorescence
boron
EPR spectroscopy
Subjects
Details
- ISSN :
- 15213765 and 09476539
- Volume :
- 26
- Database :
- OpenAIRE
- Journal :
- Chemistry – A European Journal
- Accession number :
- edsair.doi.dedup.....8e3d1888f907e543244aff9ba96004ae