Probing the inner space of resorcinarene molecular capsules with nitroxide guests.

In quarantine: Nitroxide spin probes are encapsulated by hexameric resorcinarene molecular capsules in dichloromethane solutions (see picture). A substantial reduction in the tumbling rates occurs upon encapsulation of two cationic probes and one neutral probe. As the molecular volume of the probe increases, the tumbling rate of the probe reflects the overall tumbling rate of the entire supramolecular assembly.