Positive magneto-LC effect in conjugated spin-bearing hexabenzocoronene

Area of Science:

• Molecular Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Hexabenzocoronene (HBC) derivatives are known for their unique electronic and self-assembly properties.
• Spin-carrying molecules are of interest for molecular magnetism and spintronics.
• Liquid crystalline phases offer ordered environments for molecular interactions.

Purpose of the Study:

• To synthesize and characterize the first neutral spin-carrying hexabenzocoronene (HBC) derivative.
• To investigate the magnetic and liquid crystalline properties of this novel HBC derivative.
• To explore the intermolecular interactions and spin dynamics in the columnar hexagonal phase.

Main Methods:

• Synthesis of a phenyl nitroxide substituted HBC with five alkyl chains.
• Differential scanning calorimetry (DSC) to probe liquid crystalline phase transitions.
• Electron paramagnetic resonance (EPR) spectroscopy to study spin behavior and intermolecular interactions.

Main Results:

• The synthesized HBC derivative forms a columnar hexagonal liquid crystalline phase.
• A positive magneto-optical effect was observed in the liquid crystalline phase.
• A surprising ΔMS = 2 transition was detected at 140 K, indicating a thermally accessible triplet state between neighboring molecules.

Conclusions:

• The successful synthesis of a neutral spin-carrying HBC derivative opens new avenues in molecular magnetism.
• The observed magneto-optical effect highlights the potential of these materials in responsive systems.
• The discovery of a thermally accessible triplet state provides insights into spin interactions in ordered columnar structures.