TY  - JOUR
A1  - Gershberg, Jana
A1  - Fennel, Franziska
A1  - Rehm, Thomas H.
A1  - Lochbrunner, Stefan
A1  - Würthner, Frank
T1  - Anti-cooperative supramolecular polymerization: a new K\(_2\)-K model applied to the self-assembly of perylene bisimide dye proceeding via well-defined hydrogen-bonded dimers
JF  - Chemical Science
N2  - A perylene bisimide dye bearing amide functionalities at the imide positions derived from amino acid L-alanine and a dialkoxy-substituted benzyl amine self-assembles into tightly bound dimers by π-π-stacking and hydrogen bonding in chloroform. In less polar or unpolar solvents like toluene and methylcyclohexane, and in their mixtures, these dimers further self-assemble into extended oligomeric aggregates in an anti-cooperative process in which even numbered aggregates are highly favoured. The stepwise transition from dimers into oligomers can not be properly described by conventional K\(_2\)-K model, and thus a new K\(_2\)-K aggregation model has been developed, which interpretes the present anti-cooperative supramolecular polymerization more appropriately. The newly developed K\(_2\)-K model will be useful to describe self-assembly processes of a plethora of other π-conjugated molecules that are characterized by a favored dimer species.
KW  - π–π Stacking
KW  - nucleation elongation
KW  - upramolecular polymerization process
KW  - dimerization
KW  - K2–K model
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-191428
VL  - 7
IS  - 3
ER  - 
TY  - JOUR
A1  - Wolter, Steffen
A1  - Aizezers, Janis
A1  - Fennel, Franziska
A1  - Seidel, Marcus
A1  - Würthner, Frank
A1  - Kühn, Oliver
A1  - Lochbrunner, Stefan
T1  - Size-dependent exciton dynamics in one-dimensional perylene bisimide aggregates
JF  - New Journal of Physics
N2  - The size-dependent exciton dynamics of one-dimensional aggregates of substituted perylene bisimides are studied by ultrafast transient absorption spectroscopy and kinetic Monte-Carlo simulations as a function of the excitation density and the temperature in the range of 25-90 degrees C. For low temperatures, the aggregates can be treated as infinite chains and the dynamics is dominated by diffusion-driven exciton-exciton annihilation. With increasing temperature the aggregates dissociate into small fragments consisting of very few monomers. This scenario is also supported by the time-dependent anisotropy deduced from polarization-dependent experiments.
KW  - rotational diffusion
KW  - spectroscopy
KW  - dyes
KW  - annihilation
KW  - migration
KW  - films
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-135190
VL  - 14
IS  - 105027
ER  -