Supramolecular assemblies based on some new methyl-substituted cucurbit[5]urils through hydrogen bonding

Three supramolecular assemblies based on three new partial methyl-substituted cucurbit5]urils, which are tetramethylcucurbit5]uril (α,γ-TMeQ5]), hexamethyl cucurbit5]uril (α,β,δ-HMeQ5]), Nonamethylcucurbit5]uril (NMeQ5]), were synthesized and structurally characterized by single-crystal X-ray diffractions. For the comparison with these new Q5]s, crystal structure of an assembly constructing with normal Q5] and K₂PtCl₆ was also reported. They are (α,γ-TMeQ5])·15(H₂O) (1), (α,β,δ-HMeQ5])·2Cl⁻·2(H₃O)⁺·7(H₂O) (2), (NMeQ5])·14(H₂O) (3), (4). In the corresponding crystal structures, the molecular encapsulates included a water molecule and lidded water molecules at both of the portals were observed. Moreover, these molecular encapsulates are connected through hydrogen bonding and formed supramolecular chains or joined in pair.