Syntheses and Properties of (Nitronyl nitroxide)-substituted Tri-phenylamine ortho-Bridged by Two Oxygen and Sulfur Atoms.

A nitronyl nitroxide unit (NN) was linked with a triphenylamine-based condensed polycyclic skeleton DOTT to form a radical substituted donor NN-DOTT. X-ray crystal structure analysis demonstrated a flat bowl shape of the DOTT unit. EPR spectra showed the localization of electron spin on the NN unit. Chemical oxidation of the DOTT unit produced radical-substituted radical cation salts NN-DOTT+  ⋅ SbF6 - and NN-DOTT+  ⋅ FeBr4 - that are stable under ambient conditions. The magnetic behavior of NN-DOTT+  ⋅ SbF6 - is characterized by the strong intramolecular ferromagnetic interaction between NN and DOTT+ . The X-ray structural analysis of NN-DOTT+  ⋅ FeBr4 - shows planar structure of DOTT and 1D mixed-stack column of NN-DOTT+ and FeBr4 - . Magnetic measurements established that NN-DOTT+  ⋅ FeBr4 - undergoes magnetic phase transition into a weak ferromagnet at 7 K.