Host-guest interaction of nitroxide radicals with water-soluble pillar[6]arenes

The host-guest interaction of nitroxide radicals with water-soluble pillar[ n ]arenes was studied for the first time by electron paramagnetic resonance spectroscopy and NMR spectroscopy. Our results showed that this interaction strongly depended on the 4-substituents of nitroxides and the cavity size of pillar[ n ]arenes. The host-guest interaction with water-soluble pillar[6]arene WP6 effectively increased the thermodynamic and kinetic stability of nitroxide radical 4-AT toward ascorbic acid, thus expanding its potential biomedical applications. The host-guest interaction of nitroxide radicals with water-soluble pillar[6]arenes has been for the first time verified in this study.