TY  - JOUR
A1  - Schulz, Alexander
A1  - Würthner, Frank
T1  - Folding-induced fluorescence enhancement in a series of merocyanine hetero-folda-trimers
JF  - Angewandte Chemie International Edition
N2  - Many dyes suffer from fast non-radiative decay pathways, thereby showing only short-lived excited states and weak photoluminescence. Here we show a pronounced fluorescence enhancement for a weakly fluorescent merocyanine (MC) dye by being co-facially stacked to other dyes in hetero-folda-trimer architectures. By means of fluorescence spectroscopy (lifetime, quantum yield) the fluorescence enhancement was explained by the rigidification of the emitting chromophore in the defined foldamer architecture and the presence of a non-forbidden lowest exciton state in H-coupled hetero-aggregates. This folding-induced fluorescence enhancement (FIFE) for specific sequences of π-stacked dyes points at a viable strategy toward improved fluorophores that relates to the approach used by nature in the green fluorescent protein (GFP).
KW  - organic chemistry
KW  - merocyanines
KW  - aggregation
KW  - dyes/pigments
KW  - fluorescence
KW  - folding
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256582
VL  - 61
IS  - 2
ER  - 
TY  - JOUR
A1  - Weh, Manuel
A1  - Rühe, Jessica
A1  - Herbert, Benedikt
A1  - Krause, Ana‐Maria
A1  - Würthner, Frank
T1  - Deracemization of Carbohelicenes by a Chiral Perylene Bisimide Cyclophane Template Catalyst
JF  - Angewandte Chemie International Edition
N2  - Deracemization describes the conversion of a racemic mixture of a chiral molecule into an enantioenriched mixture or an enantiopure compound without structural modifications. Herein, we report an inherently chiral perylene bisimide (PBI) cyclophane whose chiral pocket is capable of transforming a racemic mixture of [5]‐helicene into an enantioenriched mixture with an enantiomeric excess of 66 %. UV/Vis and fluorescence titration studies reveal this cyclophane host composed of two helically twisted PBI dyes has high binding affinities for the respective homochiral carbohelicene guests, with outstanding binding constants of up to 3.9×10\(^{10}\) m\(^{-1}\) for [4]‐helicene. 2D NMR studies and single‐crystal X‐ray analysis demonstrate that the observed strong and enantioselective binding of homochiral carbohelicenes and the successful template‐catalyzed deracemization of [5]‐helicene can be explained by the enzyme‐like perfect shape complementarity of the macrocyclic supramolecular host.
KW  - chirality transfer
KW  - cyclophanes
KW  - deracemization
KW  - dyes/pigments
KW  - template catalysis
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-244787
VL  - 60
IS  - 28
SP  - 15323
EP  - 15327
ER  - 
TY  - JOUR
A1  - Seifert, Sabine
A1  - Shoyama, Kazutaka
A1  - Schmidt, David
A1  - Würthner, Frank
T1  - An electron-poor C\(_{64}\) nanographene by palladium-catalyzed cascade C-C bond formation: one-pot synthesis and single-crystal structure analysis
JF  - Angewandte Chemie-International Edition
N2  - Herein, we report the one-pot synthesis of an electron-poor nanographene containing dicarboximide groups at the corners. We efficiently combined palladium-catalyzed Suzuki-Miyaura cross-coupling and dehydrohalogenation to synthesize an extended two-dimensional pi-scaffold of defined size in a single chemical operation starting from N-(2,6-diisopropylphenyl)-4,5-dibromo-1,8-naphthalimide and a tetrasubstituted pyrene boronic acid ester as readily accessible starting materials. The reaction of these precursors under the conditions commonly used for Suzuki-Miyaura cross-coupling afforded a C\(_{64}\) nanographene through the formation of ten C-C bonds in a one-pot process. Single-crystal X-ray analysis unequivocally confirmed the structure of this unique extended aromatic molecule with a planar geometry. The optical and electrochemical properties of this largest ever synthesized planar electron-poor nanographene skeleton were also analyzed.
KW  - Graphene nanoribbons
KW  - Liquid-crystalline
KW  - dyes/pigments
KW  - polycyclic aromatic hydrocarbons
KW  - two-dimensional nanostructures
KW  - Aromatic-hydrocarbon
KW  - Carbon
KW  - Dyes
KW  - Functionalization
KW  - cascade reactions
KW  - nanographene
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-188889
VL  - 55
IS  - 22
ER  - 
TY  - THES
A1  - Schmidt, Ralf
T1  - Hamilton-Receptor-Mediated Self-Assembly of Merocyanine Dyes into Supramolecular Polymers
T1  - Hamilton-Rezeptor-vermittelte Selbstorganisation von Merocyaninfarbstoffen zu supramolekularen Polymeren
N2  - Die Selbstorganisation von Merocyaninfarbstoffen zu supramolekularen Polymeren wurde untersucht. Dabei konnte die Anordnung der hoch dipolaren Farbstoffe durch die Verwendung von verschiedenen Kombinationen von Wasserstoffbrückenbindungsmotiven und dipolarer Aggregation der Chromophore gesteuert.
N2  - The self-assembly of merocyanine dyes into supramolecular polymers has been studied. Thereby, the spacial arrangement of the highly dipolar dyes has been controled by employing different combinations of hydrogen bonding motifs and dipolar aggregation of the chromophores.
KW  - Selbstorganisation
KW  - Merocyanine
KW  - Polymere
KW  - Supramolekulare Struktur
KW  - Organische Chemie
KW  - cooperativity
KW  - dipolar aggregation
KW  - dyes/pigments
KW  - hydrogen bond
KW  - self-assembly
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-56265
ER  -