Observation of face-to-face host-guest associated states prior to threading of dialkylammonium ions into the DB24C8-like openings of a molecular cage.

The threading of bis(dialkylammonium) ions through the DB24C8-like openings of a molecular cage proceeds through a stepwise mechanism: formation of a face-to-face complex between the NH2(+) centers and the crown ether, significant dissociation of this complex, and passage of the terminus of the cation through the macrocycle.