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

Three supramolecular assemblies based on three new partial methyl-substituted cucurbit[5]urils, which are tetramethylcucurbit[5]uril (α,γ-TMeQ[5]), hexamethyl cucurbit[5]uril (α,β,δ-HMeQ[5]), Nonamethylcucurbit[5]uril (NMeQ[5]), were synthesized and structurally characterized by single-crystal X-ray diffractions. For the comparison with these new Q[5]s, crystal structure of an assembly constructing with normal Q[5] and K2PtCl6 was also reported. They are (α,γ-TMeQ[5])·15(H2O) (1), (α,β,δ-HMeQ[5])·2Cl−·2(H3O)+·7(H2O) (2), (NMeQ[5])·14(H2O) (3), (Q[5])2·[K(H2O)]2+·[PtCl6]2-·24(H2O) (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.