Cooperative Binding of Cucurbit[n]urils and ß-Cyclodextrin to Heteroditopic Imidazolium-Based Guests.

Imidazolium-based guests containing two distinct binding epitopes are capable of binding ß-cyclodextrin and cucurbit[6/7]uril (CB) simultaneously to form heteroternary 1:1:1 inclusion complexes. In the final configuration, the hosts occupy binding sites disfavored in the binary complexes because of the chemically induced reorganization of the intermediate 1:1 aggregate. In addition, the reported guests are capable of binding two CBs to form either 1:2 or 1:1:1 ternary assemblies despite consisting of a single cationic moiety. Whereas the adamantane site binds CB solely via hydrophobic interactions, the CB unit at the butyl site is stabilized by a combination of hydrophobic and ion-dipole interactions.

Determination of intrinsic binding modes by mass spectrometry: gas-phase behavior of adamantylated bisimidazolium guests complexed to cucurbiturils.

Adamantylated bisimidazolium cations exhibit a distinct fragmentation pathway in contrast to their cucurbit[7]uril (CB7) complexes. The observed alternative fragmentation of the guest molecule in a complex clearly correlates to the supposed sterically hindered or allowed slippage of the macrocycle over the axel molecule.

1-(1-Adamantylmeth-yl)-1H-benzimidazole.

The asymmetric unit of the title compound, C(18)H(22)N(2), contains two independent mol-ecules which differ slightly with respect to the torsion angles involving the atoms joining the adamantyl and benzimidazole groups. The bond angles in the adamantane cage vary within the range 108.27 (9)-110.55 (10)°. The benzimidazole ring system in both mol-ecules is essentially planar, the maximum deviations from the best planes being 0.0134 (15) and 0.0229 (14) Å. In the crystal, weak C-H⋯π inter-actions link the molecules.

1-(Bromo-meth-yl)adamantane.

The title compound, C(11)H(17)Br, has crystallographically imposed mirror symmetry in the solid state with mol-ecules bis-ected by mirror planes parallel to the crystallographic ac plane (five C atoms, three H atoms and the Br atom lie on the mirror plane). The asymmetric unit contains one half-mol-ecule. The crystal packing is stabilized only via weak non-specific van der Waals inter-actions.