A Persistent Open-Shell m-QDM-Type Diindenoanthracene Diradicaloid with a Large Diradical Character.

Area of Science:

• Organic Chemistry
• Materials Science
• Quantum Chemistry

Background:

• Indenofluorenes (IFs) are of interest due to their antiaromaticity, diradical character, and narrow band gaps.
• Diradicaloids are molecules with significant diradical character, impacting their electronic and magnetic properties.

Purpose of the Study:

• To synthesize and characterize a novel m-QDM-type indenofluorene-based diradicaloid.
• To investigate the structure-property relationships, including diradical character, stability, and reactivity.
• To explore the electronic and magnetic properties of the synthesized diradicaloid.

Main Methods:

• Synthesis of the indenofluorene-based diradicaloid.
• Comprehensive characterization using spectroscopic techniques (e.g., VT-EPR, SQUID).
• Structural analysis and stability studies in solid-state and solution.

Main Results:

• A novel m-QDM-type IFs-based diradicaloid with a large diradical character (y0 = 0.87) was synthesized.
• A stable crystalline derivative (2b) was obtained, exhibiting solid-state stability but gradual decomposition in solution.
• The compound shows low-energy absorption (>1300 nm) and a narrow singlet-triplet energy gap, leading to paramagnetic behavior.

Conclusions:

• The study provides insights into the structure-property relationships of diradicaloids.
• The findings guide the rational design and synthesis of new diradicaloid and polyradicaloid systems.
• The synthesized diradicaloid demonstrates potential for applications in materials science due to its unique electronic and magnetic properties.