Synthesis, Characterization, and Applications of Novel Stable Nitroxide Radical-Bearing π-Conjugated Organic Materials

Abstract

Attention has been paid to study on nitroxide radicals connected to π-conjugated organic materials due to their unique photophysical, magnetic, and electrochemical properties. Although their potential applications are extensive in biology, chemistry, and physics, insufficient studies on their supramolecular properties in aggregated states limits practical use, so far. Furthermore, only a few examples and strategies have been reported to fabricate nanostructures with nitroxide radicals. Herein, we report novel π-conjugated organic materials containing nitroxide radicals forming self-assembled nanostructures. The molecules were strategically designed and successfully synthesized in good yield. Unique properties of the nitroxide radicals were investigated by electron spin resonance measurements, UV-Vis spectroscopy, and electrochemical measurements. Interestingly, self-assembled nanoparticles were fabricated via simple re-precipitation methods and exhibited paramagnetism. Furthermore, as the ascorbic acid sensor applications, the molecules exhibited superior sensing properties with high sensitivity, good selectivity, a broad detection range, and dual-mode detection. Finally, we successfully demonstrated their sensing ability in aqueous conditions by using self-assembled nanoparticles.