A Stable Radical-Substituted Radical Cation with Strongly Ferromagnetic Interaction:  Nitronyl Nitroxide-Substituted 5,10-Diphenyl-5,10-dihydrophenazine Radical Cation

A stable radical-substituted radical ion with strongly ferromagnetic intramolecular interaction (J) between the radical and radical ion sites is an attractive spin building block of organic magnets. We prepared 2-nitronyl nitroxide-substituted 5,10-diphenyl-5,10-dihydrophenazine radical cation, 1⁺. The 1⁺ salt was stable under aerated conditions at room temperature and had a large J/k_B value (≥+700 K).