Coordinative halogen bonds have recently gained interest for the assembly of supramolecular capsules. Ion mobility-mass spectrometry and theoretical calculations now reveal the well-defined gas-phase structures of dimeric and hexameric [N···I +···N] halogen-bonded capsules with counterions located inside their cavities as guests. The solution reactivity of the large hexameric capsule shows the intriguing solvent-dependent equilibrium between the hexamer and an unprecedented pentameric [N···I +···N] halogen-bonded capsule, when the solvent is changed from chloroform to dichloromethane. The intrinsic flexibility of the cavitands enables this novel structure to adopt a pseudo-trigonal bipyramidal geometry with nine [N···I +···N] bonds along the edges and two pyridine binding sites uncomplexed.
†Dedicated to Prof. Helmut Schwarz on the occasion of his 75th birthday.
‡Electronic supplementary information (ESI) available. See DOI: 10.1039/c8sc03040e