Synthetic Access to a Pure Polyradical Architecture: Nucleophilic Insertion of Nitronyl Nitroxide on a Cyclotriphosphazene Scaffold

An optimized nucleophilic synthetic approach featuring mild conditions and microwave energy was utilized to circumvent the classical Ullman procedure and access a polynitronyl nitroxide radical easily and in pure form. The simultaneous controlled introduction of preformed nitronyl nitroxide radicals on a cyclotriphosphazene core leads to a novel polyphosphazene monomer which is suitable for both n- and a p-type redox-active material in organic rechargeable batteries as demonstrated by electrochemistry. Additionally, absorption spectra and square-wave voltammetry were utilized to quantify the number of nitronyl nitroxide radical units on the cyclotriphosphazene scaffold.