Magnetic Bistability in a Discrete Organic Radical

Molecular
assembly with magnetic bistability has been of considerable
interest for application as electronic devices. In contrast to transition-metal
complexes, magnetic bistability so far observed in organic radical
crystals is mainly caused by intermolecular electron-exchange interaction.
We now report that the magnetic bistability in an organic radical
can also be caused by intramolecular electron-exchange interaction.
The diradical salt of 1,4-di­(bisphenylamino)-2,3,5,6,-tetramethylbenzene
undergoes a phase transition with a thermal hysteresis loop over the
temperature range from 118 to 131 K. The phases above and below the
loop correspond to two different singlet states of the diradical dication.
The results provide a novel organic radical material as an unprecedented
instance of an intramolecular magnetic bistability revalent to the
design of functional materials.