Capsoplexes: encapsulating complexes via guest recognition.

A new dinuclear Ni-NHC complex is able to selectively recognise and self-assemble with guests via tennis-ball like encapsulation, exemplarily demonstrated employing halides. Addition of chloride or bromide leads to the formation of capsules with small cavities which are stabilised through non-classical hydrogen bonds and Coulomb interactions between the anion and the metal centres.