Anion-mediated properties of a metal complex in a hexameric resorcin[4]arene cage: chirality induction, kinetics and reactivity

The influence of anions associated with a metal complex on host–guest assembly properties within a hexameric resorcinarene cage was investigated by UV-vis, EPR and electronic circular dichroism spectroscopies and by molecular dynamics (MD) simulations. Upon encapsulation, the metal complex has restricted mobility but conserves its reactivity towards ligand exchange at the metal centre. Only under light irradiation, the behavior of the metal complex is altered by its encapsulation. Also, the counter-ion strongly affects the encapsulation kinetics. MD simulations suggest that this effect can be triggered when the exchange of a structuring water molecule by the anion within the cage wall is possible. Finally, a double chirality induction is observed from a chiral counter-ion to the capsule and to the encapsulated cationic complex moiety itself.