Coronenohelicenes with Dynamic Chirality.

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Chiral nonplanar aromatic molecules are crucial for advanced optical and electronic applications.
• Helicenes and perylene derivatives are known for their unique photophysical and structural properties.

Purpose of the Study:

• To synthesize and characterize novel chiral, nonplanar aromatic compounds integrating perylene and helicene moieties.
• To investigate the impact of fusing helicene units on the electronic and chiroptical properties of perylene-based systems.

Main Methods:

• Chemical synthesis of fused perylene-coronene-helicene systems.
• Spectroscopic analysis (UV-Vis, fluorescence) and chiral chromatography for isomer separation and characterization.
• Determination of isomerization barriers using experimental methods.

Main Results:

• Successful synthesis of novel perylene-coronene-helicene hybrids with tunable chirality.
• Identification of six distinct isomers, including enantiomers and meso forms, from double helicene fusion.
• Measured high dissymmetry factors (up to 1.2×10⁻²) in chiroptical properties, indicating strong circular dichroism.
• Isomerization barriers were found to be slightly higher than those of parent helicenes.

Conclusions:

• The fusion of helicene units to perylene cores creates highly chiral and dynamic nonplanar aromatic systems.
• These novel compounds exhibit significant chiroptical properties, driven by the combined electronic nature of perylene and the chirality of helicenes.
• The developed synthetic strategies and characterization methods pave the way for designing advanced chiral materials.