Inclusion and exclusion complexes of cucurbit[7]uril with silver cations

Abstract We describe a strategy to prepare cucurbit [7]uril(Q [7])-M n + complexes in an ammonia medium, in which a competitive coordination of metal ions to ammonia molecules or Q [7] molecules occurs. Using this strategy, a novel compound consisting of Q [7] and a metal Ag + ion was obtained. The X-ray crystal structure of this compound showed an infinite 2D network comprising three-Q [7] units and with a cavity size of around 11.0 A × 5.5 A. Moreover, a Q [7]-based host-guest inclusion Ag + aquo complex was observed. Considering the generality of the behavior shown in the complexes described, this phenomenon may well deserve further study.