Interaction models of three alkyl substituted cucurbit[6]urils with a hydrochloride salt of 4,4′-dipyridyl guest

Three host–guest complexes, {(H2O)2@(CyH)2Q[6]} (4,4′-bpyH)+·Cl−·10H2O (1), {(1,4-dioxane)@m-TriCyHQ[6]}(4,4′-bpyH)+·Cl−·19H2O (2), {(4,4′-bpyH2)2+@TMeQ[6]}·2Br−·11H2O (3), were prepared with three different alkyl substituted cucurbit[6]urils, symmetrical dicyclohexanocucurbit[6]uril {(CyH)2Q[6]}, meta tricyclohexanocucurbit[6]uril (m-TriCyHQ[6]), symmetrical tetramethylcucurbit[6]uril (TMeQ[6]), and a HCl salt 4,4′-dipyridyl(4,4′-bpyHCl) or a HBr salt 4,4′-dipyridyl[4,4-bpy(HBr)2] guest. Their crystal structures characterized by single-crystal X-ray diffractions revealed that these hosts can form supramolecular assemblies with the halogen hydride salts of the guest 44bpy through the ion–dipole interaction, hydrogen bonding, C–H⋯π or N–H⋯π interaction and π⋯π stacking. The substituted alkyl group could affect the interaction model and assembled characteristic of the host and the guest.