A Robust Porphyrin-Stabilized Triplet Carbon Diradical

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• The development of stable high-spin carbon radicals is crucial for advanced applications.
• Porphyrin-based systems offer a promising scaffold for radical stabilization.

Purpose of the Study:

• To synthesize and characterize novel porphyrin-stabilized carbon radicals.
• To explore the influence of fused aromatic systems on radical stability and spin state.

Main Methods:

• Multi-step synthesis involving Suzuki-Miyaura coupling, Grignard addition, Friedel-Crafts alkylation, and oxidation.
• Characterization of synthesized molecules, including singly and doubly naphthalene-fused porphyrins and anthracene-bridged porphyrin dimers.
• Stability studies under ambient conditions and elevated temperatures.

Main Results:

• Successful synthesis of a singly naphthalene-fused porphyrin radical, confirmed as a stable monoradical.
• Doubly naphthalene-fused porphyrins and anti-fused-anthracene-bridged porphyrin dimers were found to be closed-shell molecules.
• The syn-fused-anthracene-bridged porphyrin dimer was identified as a highly stable triplet ground-state carbon diradical with a half-life of 28 days at 80°C.

Conclusions:

• The strategy enables the synthesis of diverse fused porphyrin architectures.
• The syn-dimer represents a significant advancement in stable high-spin carbon diradical chemistry.
• These findings open avenues for exploring high-spin organic materials with tunable properties.