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.