An EPR and NMR study of supramolecular effects on paramagnetic interaction between a nitroxide incarcerated within a nanocapsule with a nitroxide in bulk aqueous media.

This paper was selected because it demonstrates several important supramolecular and electron spin effects originating from a paramagnetic species, selected to mimic the behavior of drugs, both external and internal into an organic capsule, which work as vehicle or carrier of the drug to selected cells or protein active sites. The main supramolecular and spin-spin effects are summarized as follows: (1) spin-spin interactions can be significant between two nitroxides, even when one is protected by the walls of a host cage; (2) spin-spin interactions can be enhanced by supramolecular binding resulting from Coulombic attractions or inhibited via Coulombic repulsions; and (3) paramagnetic nuclear relaxation of guest and internal relaxants can be employed to elucidate supramolecular interactions and structures. These results are significant for all the scientists working in the field of supramolecular nanostructures and, mainly to those interested to use these structures for drug transport and curing various diseases.