TY  - JOUR
A1  - Hecht, Markus
A1  - Leowanawat, Pawaret
A1  - Gerlach, Tabea
A1  - Stepanenko, Vladimir
A1  - Stolte, Matthias
A1  - Lehmann, Matthias
A1  - Würthner, Frank
T1  - Self‐Sorting Supramolecular Polymerization: Helical and Lamellar Aggregates of Tetra‐Bay‐Acyloxy Perylene Bisimide
JF  - Angewandte Chemie International Edition
N2  - A new perylene bisimide (PBI), with a fluorescence quantum yield up to unity, self‐assembles into two polymorphic supramolecular polymers. This PBI bears four solubilizing acyloxy substituents at the bay positions and is unsubstituted at the imide position, thereby allowing hydrogen‐bond‐directed self‐assembly in nonpolar solvents. The formation of the polymorphs is controlled by the cooling rate of hot monomer solutions. They show distinctive absorption profiles and morphologies and can be isolated in different polymorphic liquid‐crystalline states. The interchromophoric arrangement causing the spectral features was elucidated, revealing the formation of columnar and lamellar phases, which are formed by either homo‐ or heterochiral self‐assembly, respectively, of the atropoenantiomeric PBIs. Kinetic studies reveal a narcissistic self‐sorting process upon fast cooling, and that the transformation into the heterochiral (racemic) sheetlike self‐assemblies proceeds by dissociation via the monomeric state.
KW  - liquid crystals
KW  - noncovalent interactions
KW  - self-assembly
KW  - structure elucidation
KW  - supramolecular chemistry
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224586
VL  - 59
IS  - 39
SP  - 17084
EP  - 17090
ER  - 
TY  - JOUR
A1  - Lambov, Martin
A1  - Hensiek, Nicola
A1  - Pöppler, Ann‐Christin
A1  - Lehmann, Matthias
T1  - Columnar Liquid Crystals from Star‐Shaped Conjugated Mesogens as Nano‐Reservoirs for Small Acceptors
JF  - ChemPlusChem
N2  - Shape‐persistent conjugated mesogens with oligothiophene arms of different lengths have been synthesized. Such mesogens possess free intrinsic space between their conjugated arms. They form columnar liquid‐crystalline phases, in which the void is filled by dense helical packing in the neat phase similar to an oligo(phenylene vinylene) derivative of equal size. The void can also be compensated by the inclusion of the small acceptor molecule 2,4,7‐trinitrofluorenone. In solution, the acceptor interacts with the core as the largest π‐surface, while in the solid material, it is incorporated between the arms and sandwiched by the star‐shaped neighbours along the columnar assemblies. The TNF acceptors are not nanosegregated from the star‐shaped donors, thus the liquid crystal structure converts to a nano‐reservoir for TNF (endo‐receptor). These host–guest arrangements are confirmed by comprehensive X‐ray scattering experiments and solid‐state NMR spectroscopy. This results in ordered columnar hexagonal phases at high temperatures, which change to helical columnar mesophases or to columnar soft crystals at room temperature.
KW  - donor-acceptor interactions
KW  - host-guest systems
KW  - intrinsic free space
KW  - liquid crystals
KW  - mesogens
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218014
VL  - 85
IS  - 10
SP  - 2219
EP  - 2229
ER  - 
TY  - JOUR
A1  - Lehmann, Matthias
A1  - Dechant, Moritz
A1  - Weh, Dominik
A1  - Freytag, Emely
T1  - Metal Phthalocyanine−Fullerene Dyads: Promising Lamellar Columnar Donor−Acceptor Liquid Crystal Phases
JF  - ChemPlusChem
N2  - Liquid crystal (LC) shape‐amphiphiles with a disc tethered to a fullerene have been intensely studied for the application in photovoltaics, and helical nanosegregation of C\(_{60}\) has been claimed around the π‐stacking disks based on X‐ray results. The most promising materials reported to date have been resynthesized and studied comprehensively by XRS, density measurements, modelling, and electron density reconstruction. In contrast to previous reports, the results indicate that metal phthalocyanine−fullerene mesogens pack in lamellar columnar phases with p2gm symmetry. Fullerenes assemble in layers and are flanked by phthalocyanine columns, thus explaining the balanced charge carrier mobility of electrons and holes. Such variable donor−acceptor structures are promising for organic electronic applications.
KW  - Donor−acceptor dyads
KW  - fullerenes
KW  - liquid crystals
KW  - nanosegregation
KW  - shape-amphiphiles
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218531
VL  - 85
IS  - 8
SP  - 1934
EP  - 1938
ER  -