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A new synthetic approach for fluorinated alkoxytriphenylene discotic liquid crystals is presented. This methodology exploits the previously described photocyclodehydrofluorination (PCDHF) reaction for the preparation of fluorinated triphenylene derivatives coupled with a variety of nucleophilic aromatic substitution (S N Ar) reactions. This particular combination of reactions provides a versatile route to discotic materials with carefully controlled core fluorine and alkoxy tail content. In the course of these studies, new discotic materials with minimal tail content have been revealed. The mesogenic properties of these materials are reported, and their charge transport properties are measured using the time of flight technique.
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Structure and dynamics of tail-free discotic liquid crystals: Simulations of fluorinated triphenylene
Recently, a large family of at least 14 discotic liquid crystals was discovered that are exceptions to the conventional paradigm that discotic mesogens tend to feature long, flexible tails on their periphery. To understand why these materials are liquid crystals, as well as the structural determinants of discotic phase behavior, we studied a group of closely related small tail-free disk-like molecules, including both mesogenic and non-mesogenic compounds differing only in the position of a single fluorine substituent. The rigidity and structural simplicity of these molecules make them well suited to for study by large, fully all-atom simulations. Using a combination of static and dynamic metrics, we were able to identify several key features of the columnar mesophase and, thereby, conclusively identify a columnar liquid crystalline mesophase present in a subset of our systems. Our simulations feature molecules hopping between columns in the columnar mesophase and distinctive molecular rotations in 60° steps about the columnar axis. The ability to create and characterize columnar mesophases in silico provides a potent tool for untangling the structural determinants of liquid crystalline behavior in these and other tail-free discotic liquid crystals.
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- Award ID(s):
- 1809536
- PAR ID:
- 10407389
- Date Published:
- Journal Name:
- The Journal of Chemical Physics
- Volume:
- 157
- Issue:
- 13
- ISSN:
- 0021-9606
- Page Range / eLocation ID:
- 134901
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1063/5.0106722
