Rational design of organic diradicals with robust high-spin ground state based on antiaromatic linkers

Area of Science:

• Organic Chemistry
• Materials Science
• Quantum Chemistry

Background:

• Fully-organic molecules with high-spin ground states are key for developing novel lightweight, flexible magnetic materials.
• Emerging technologies like spintronics require advanced materials with specific magnetic properties.

Purpose of the Study:

• To explore the potential of diradicals using diphenylmethyl-based open-shell cores linked by pentalene and diazapentalene antiaromatic couplers.
• To identify diradicals with robust triplet ground states suitable for magnetic applications.

Main Methods:

• Utilized accurate electronic structure calculations.
• Targeted non-bonding and non-disjoint frontier molecular orbitals.
• Investigated various pentalene and diazapentalene-based antiaromatic couplers, including dibenzopentalenes and acene-inserted derivatives.

Main Results:

• Identified diradicals with robust triplet ground states.
• Observed singlet-triplet energy gaps up to ten times room temperature thermal energy.
• Demonstrated strong π-system interactions between open-shell centers and antiaromatic couplers.
• Showcased enhanced stability and significant spin density delocalization in the diradicals.

Conclusions:

• Pentalene-based diradicals show significant potential as building blocks for advanced fully organic magnetic materials.
• The designed diradicals exhibit favorable properties for spintronics and other emerging technological applications.
• Strong π-system interactions are crucial for achieving high-spin states and enhanced stability.