TY  - JOUR
A1  - Griesbeck, Stefanie
A1  - Michail, Evripidis
A1  - Rauch, Florian
A1  - Ogasawara, Hiroaki
A1  - Wang, Chenguang
A1  - Sato, Yoshikatsu
A1  - Edkins, Robert M.
A1  - Zhang, Zuolun
A1  - Taki, Masayasu
A1  - Lambert, Christoph
A1  - Yamaguchi, Shigehiro
A1  - Marder, Todd B.
T1  - The Effect of Branching on the One‐ and Two‐Photon Absorption, Cell Viability, and Localization of Cationic Triarylborane Chromophores with Dipolar versus Octupolar Charge Distributions for Cellular Imaging
JF  - Chemistry – A European Journal
N2  - Two different chromophores, namely a dipolar and an octupolar system, were prepared and their linear and nonlinear optical properties as well as their bioimaging capabilities were compared. Both contain triphenylamine as the donor and a triarylborane as the acceptor, the latter modified with cationic trimethylammonio groups to provide solubility in aqueous media. The octupolar system exhibits a much higher two‐photon brightness, and also better cell viability and enhanced selectivity for lysosomes compared with the dipolar chromophore. Furthermore, both dyes were applied in two‐photon excited fluorescence (TPEF) live‐cell imaging.
KW  - boranes
KW  - cell imaging
KW  - fluorescence
KW  - lysosome
KW  - two-photon excited fluorescence
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-212887
VL  - 25
IS  - 57
SP  - 13164
EP  - 13175
ER  - 
TY  - JOUR
A1  - Rauch, Florian
A1  - Fuchs, Sonja
A1  - Friedrich, Alexandra
A1  - Sieh, Daniel
A1  - Krummenacher, Ivo
A1  - Braunschweig, Holger
A1  - Finze, Maik
A1  - Marder, Todd B.
T1  - Highly Stable, Readily Reducible, Fluorescent, Trifluoromethylated 9‐Borafluorenes
JF  - Chemistry – A European Journal
N2  - 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 \(^{F}\)Xyl\(^{F}\)Bf, \(^{F}\)Xyl: 2,6‐bis(trifluoromethyl)phenyl), a trifluoromethyl group (\(^{F}\)Mes\(^{F}\)Bf, \(^{F}\)Mes: 2,4,6‐tris(trifluoromethyl)phenyl) or a dimethylamino group (p‐NMe\(_{2}\)‐\(^{F}\)Xyl\(^{F}\)Bf, p‐NMe\(_{2}\)‐\(^{F}\)Xyl: 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 \(^{F}\)Mes\(^{F}\)Bf 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‐NMe\(_{2}\)‐\(^{F}\)Xyl\(^{F}\)Bf exhibits thermally activated delayed fluorescence (TADF) from a charge‐transfer (CT) state, whereas the \(^{F}\)Mes\(^{F}\)Bf and FXylFBf borafluorenes exhibit only weakly allowed locally excited (LE) transitions due to their symmetry and low transition‐dipole moments.
KW  - borafluorenes
KW  - boron
KW  - EPR spectroscopy
KW  - fluorescence
KW  - heterocycles
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218390
VL  - 26
IS  - 56
SP  - 12794
EP  - 12808
ER  -