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RESEARCH PRODUCT
Synthesis and helical supramolecular organization of discotic liquid crystalline dibenzo[hi,st]ovalene
Steven De FeyterAkimitsu NaritaAkimitsu NaritaWojciech ZajaczkowskiQiang ChenWojciech PisulaWojciech PisulaJohannes SeibelKlaus MüllenKlaus Müllensubject
TechnologyMaterials scienceMaterials ScienceStackingSupramolecular chemistryMaterials Science Multidisciplinary02 engineering and technologyOvalene010402 general chemistry01 natural sciencesPhysics Appliedchemistry.chemical_compoundHighly oriented pyrolytic graphitePhase (matter)Materials ChemistrySide chainCHARGE-TRANSPORTScience & TechnologyBilayerPhysicsHEXA-PERI-HEXABENZOCORONENESGeneral Chemistry021001 nanoscience & nanotechnology0104 chemical sciencesCrystallographychemistryMOBILITYPhysical SciencesAlkoxy groupDISK-LIKE MOLECULES0210 nano-technologydescription
Dibenzo[hi,st]ovalene (DBOV) has emerged as a new polycyclic aromatic hydrocarbon (PAH) with intriguing optical properties with strong red emission. Nevertheless, DBOV derivatives thus far synthesized either had mesityl groups that hinder the pi-pi stacking of the aromatic cores or showed low solubility, and the self-assembly of DBOVs has not been investigated. In this work, two 3,4,5-tris(dodecyloxy)phenyl (TDOP) groups are introduced at the meso-positions of DBOV in order to enhance its solubility without compromising the intermolecular interactions. The obtained DBOV-TDOP forms at elevated temperatures a discotic liquid crystalline phase. Due to pi-pi-stacking interactions as well as local phase separation between the aromatic cores and the flexible alkoxy side chains, the DBOV-TDOP molecules self-assemble into columnar stacks. In the low temperature phase, the space demanding TDOP substituents induce a rotation of the discs towards each other leading to an exceptionally long helical pitch within the columnar structures. Moreover, scanning tunnelling microscopy (STM) elucidates intriguing self-assembly of DBOV-TDOP at the interface of highly oriented pyrolytic graphite (HOPG) and 1-phenyloctane (PO). Individual molecules are visualized by STM, revealing that the alkyl chains protrude from the surface into the solution and suggesting that a self-assembled bilayer film structure is predominantly formed.
year | journal | country | edition | language |
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2019-01-01 |