title: Characterization of host-guest complexes of cucurbit[n]uril (n = 6, 7) by electrospray ionization mass spectrometry.
abstract: When an intramolecular cavity exists in a molecule, it can trap another chemical species to form a host-guest complex. We examine the formation of such an inclusion complex with cucurbit[n]uril (CBn, n = 6, 7) as the host to trap alkali metal or ammonium ions as the guest, by electrospray ionization mass spectrometry (ESI-MS). The results show that the inclusion complexes are formed between the three-dimensional cylinder of CBn hosts and the guest cations. Selectivity of the complex formation is dependent both on (1) ion-dipole interactions between the cylindrical portal of the CBn hosts and the guest cations and (2) the hydrophobic interactions at the inner cavity of CBn.
authors.affiliation: Department of Applied Chemistry, Kansai University, Yamatecho, Suita 564-8680, Japan.
authors.forename: Issey
authors.initials: I
authors.lastname: Osaka
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kondou
authors.forename: Narayanan
authors.initials: N
authors.lastname: Selvapalam
authors.forename: Shashadhar
authors.initials: S
authors.lastname: Samal
authors.forename: Kimoon
authors.initials: K
authors.lastname: Kim
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Rekharsky
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Inoue
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Arakawa