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Published on: August 19, 2013
Unusual molecular conformations in fluorinated, contorted hexabenzocoronenes
Yueh-Lin Loo1, Anna M Hiszpanski, Bumjung Kim
1Department of Chemical & Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States. lloo@princeton.edu
Organic Letters
|October 7, 2010
Summary
New fluorinated hexabenzocoronenes (HBCs) exhibit a unique, metastable conformation due to fluorine interactions. This conformation converts to a stable form upon heating, indicating a kinetically arrested state during synthesis.
Area of Science:
- Organic Chemistry
- Materials Science
- Supramolecular Chemistry
Background:
- Hexabenzocoronenes (HBCs) are disc-shaped aromatic molecules with unique electronic and optical properties.
- Fluorination of HBCs can tune their properties and influence their self-assembly.
- Contorted HBC derivatives present challenges in synthesis and conformational control.
Purpose of the Study:
- To synthesize novel fluorinated, contorted hexabenzocoronenes (HBCs).
- To investigate the impact of fluorine-fluorine interactions on HBC conformation.
- To understand the thermal stability and conformational dynamics of these novel HBCs.
Main Methods:
- Suzuki-Miyaura coupling of fluorinated phenyl boronic acids.
- Photocyclization and Scholl cyclization for HBC core formation.
- Thermal analysis to study conformational transitions.
Main Results:
- Facile synthesis of fluorinated, contorted HBCs was achieved.
- A previously unobserved metastable conformation was identified, stabilized by intramolecular fluorine-fluorine interactions.
- Heating above 100 °C irreversibly converted the metastable conformation to a stable form.
Conclusions:
- Fluorinated HBCs can adopt unique metastable conformations driven by specific intermolecular interactions.
- The observed metastable state is likely a kinetically trapped conformation formed during the cyclization process.
- These findings offer new insights into controlling the structure and properties of complex aromatic systems.
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