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  - JOUR
A1  - Bialas, David
A1  - Zitzler-Kunkel, André
A1  - Kirchner, Eva
A1  - Schmidt, David
A1  - Würthner, Frank
T1  - Structural and quantum chemical analysis of exciton coupling in homo- and heteroaggregate stacks of merocyanines
JF  - Nature Communications
N2  - Exciton coupling is of fundamental importance and determines functional properties of organic dyes in (opto-)electronic and photovoltaic devices. Here we show that strong exciton coupling is not limited to the situation of equal chromophores as often assumed. Quadruple dye stacks were obtained from two bis(merocyanine) dyes with same or different chromophores, respectively, which dimerize in less-polar solvents resulting in the respective homo- and heteroaggregates. The structures of the quadruple dye stacks were assigned by NMR techniques and unambiguously confirmed by single-crystal X-ray analysis. The heteroaggregate stack formed from the bis(merocyanine) bearing two different chromophores exhibits remarkably different ultraviolet/vis absorption bands compared with those of the homoaggregate of the bis(merocyanine) comprising two identical chromophores. Quantum chemical analysis based on an extension of Kasha’s exciton theory appropriately describes the absorption properties of both types of stacks revealing strong exciton coupling also between different chromophores within the heteroaggregate.
KW  - exciton coupling
KW  - merocyanines
KW  - quantum chemical analysis
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170200
VL  - 7
ER  -