Aethrene: A Stable Polycyclic Aromatic Hydrocarbon With a Triplet Ground State

Area of Science:

• Organic Chemistry
• Materials Science
• Quantum Chemistry

Background:

• High-spin radicals are crucial for organic electronics and spintronics due to their unique electronic and magnetic properties.
• The inherent reactivity of high-spin radicals presents significant challenges in their synthesis and isolation.
• Developing stable high-spin radical compounds is essential for advancing these fields.

Purpose of the Study:

• To design and synthesize a novel, stable high-spin radical compound.
• To investigate the electronic structure and magnetic properties of the synthesized compound.
• To explore the potential applications of this stable radical in organic electronics and spintronics.

Main Methods:

• Aethrene derivative 2 was designed with an A-shaped skeleton and bulky substituents for enhanced stability.
• X-ray crystallographic analysis was employed to confirm the molecular structure.
• Density Functional Theory (DFT) calculations, electron paramagnetic resonance (EPR), and superconducting quantum interference device (SQUID) measurements were used to determine the ground state.

Main Results:

• The synthesized aethrene derivative 2 demonstrated remarkable stability with a half-life of 15.5 days under ambient conditions.
• Experimental and computational methods confirmed that aethrene 2 possesses a triplet ground state.
• The dication of aethrene 2 was successfully synthesized and shown to have a closed-shell ground state.

Conclusions:

• A novel, stable high-spin radical PAH was successfully designed and synthesized.
• The study provides insights into overcoming the reactivity challenges associated with high-spin radicals.
• This work paves the way for the development of new stable polycyclic aromatic hydrocarbons (PAHs) with high-spin multiplicity for advanced electronic and spintronic applications.