Structures of supramolecular assemblies formed by some partial substituted cucurbiturils and some metal ion complexes

Three supramolecular assemblies based on substituted cucurbit[6]uril: α,δ-tetramethylcucurbit[6]uril (TMeQ[6]) and α,γ,ε-tricyclohexylcucurbit-[6]uril (m-TriCyHQ[6]), and α,γ,ε-hexamethylcucurbit[6]uril (m-HMeQ[6]) with different metal ions were synthesized and structurally characterized by single-crystal X-ray diffractions. They are {TMeQ[6]@acetone[Ca(H2O)3]}2+·(CdCl4)2−10H2O (1), {[m-TriCyHQ[6]@dioxane][Na(H2O)2Cl]}15H2O (2) and {[m-HMeQ[6]]K2(H2O)4 Cl}Cl·15H2O (3). The crystal structures of these complexes showed the different interaction modes between these partial alkyl-substituted cucurbit[6]urils and the metal ions. In compound 1, a one-dimensional supramolecular chain of alternating TMeQ[6] molecules and [Ca(H2O)3]2+ complexes assembled through coordination bonding of the cation and the carbonyl oxygen of TMeQ[6]. The compound 2 was the first reported crystal structure of the m-TriCyHQ[6] with metal ion through the coordinate bonds, and the compound 3 was the first reported crystal structure of m-HMeQ[6]. It was unexpected that an ionic bonded chloride anion was at the portal of the two meta-substituted cucurbiturils.