Issue 41, 2019

Synthesis and helical supramolecular organization of discotic liquid crystalline dibenzo[hi,st]ovalene

Abstract

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 π–π 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 π–π-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.

Graphical abstract: Synthesis and helical supramolecular organization of discotic liquid crystalline dibenzo[hi,st]ovalene

Supplementary files

Article information

Article type
Paper
Submitted
21 Jun 2019
Accepted
27 Aug 2019
First published
27 Aug 2019
This article is Open Access
Creative Commons BY license

J. Mater. Chem. C, 2019,7, 12898-12906

Synthesis and helical supramolecular organization of discotic liquid crystalline dibenzo[hi,st]ovalene

Q. Chen, W. Zajaczkowski, J. Seibel, S. De Feyter, W. Pisula, K. Müllen and A. Narita, J. Mater. Chem. C, 2019, 7, 12898 DOI: 10.1039/C9TC03350E

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