Supramolecular assemblies based on the interaction of a copper dication with alky-substituted cucurbit[6]urils

In this study, we describe the interaction of copper cations with alkyl-substituted cucurbiturils (SQ[6])s in the absence and presence of a third species, and show how the corresponding supramolecular assemblies depend on the addition of the third species. In the absence of the third species, the SQ[6]s resulted in similar coordination with copper cations and the formation of supramolecular assemblies as the unsubstituted cucurbituril (Q[6]). The Cu2+ cation was coordinated to a cyclopentanocucurbit[6]uril (CyP6Q[6]) with the counter anion NO3− and formed a zigzag coordination chain. In contrast, the Cu2+ cation coordinated to a symmetrical tetramethylcucurbit[6]uril (TMeQ[6]) with the counter anion Cl− and formed a tubular coordination polymer. However, when SO42− was introduced into the Cu2+–TMeQ[6] system, only isolated complexes consisting of linear coordination polymers of Cu2+ to TMeQ[6] were formed. By comparison, when the organic molecule p-phenylenediamine was introduced into the CuCl2–TMeQ[6]–HCl system, no Cu2+–TMeQ[6] complexes were formed at all but p-phenylenediamine@TMeQ[6] host–guest inclusion complexes were observed.

In the present study, we describe the interaction of copper cations with alkyl-substituted cucurbiturils (SQ[6])s in the absence and presence of a third species. The corresponding supramolecular assemblies are dependent upon the addition of the third species.Figure optionsDownload as PowerPoint slide