EPR STUDIES OF THE BISTABILITY IN CF₃CNSSN

Abstract

Condensation of CF₃C(═NH)NH₂ with SCl₂ yielded the dithiadiazolylium salt, [CF₃CNSSN]Cl which could be reduced to [CF₃CNSSN]₂ with Zn/Cu couple in SO₂. [CF₃CNSSN]₂ is a diamagnetic dimer in the solid state but melts at 308 K to give a paramagnetic liquid. On cooling the radical enters a metastable state before immediately re-solidifying below 295 K. The thermal hysteresis was probed by EPR spectroscopy. Metastable samples spontaneously solidified after an induction period, typically between ca. 5 and 30 min, consistent with the variable time necessary to form a seed crystal from which crystallization can occur.

Keywords:

• Bistability
• dithiadiazolyl
• metastable