Four bidentate, dicationic ligands (L12+-L42+) were prepared and investigated as guests for binding by the cucurbituril (CB) host and structural components for metal (Pd and Pt)-coordinated self-assembly into metallacycles. In aqueous solutions, all the ligands were found to form stable complexes of variable stoichiometries with CB, and only one (L22+) failed to self-assemble, induced by the presence of suitable Pd or Pt complexes, into metallacycles. Exposure of the Pd-based metallacycles to CB led to their disassembly at room temperature, while the Pt-based metallacycles remained stable under these conditions. However, heating of the Pt metallacycles in the presence of CB also led to their disassembly. This interplay between the interactions in aqueous media of the L12+, L32+, and L42+ ligands with the CB host and Pd (or Pt) complexes suggests the possibility of using these or related systems for controlled drug delivery applications.
ASJC Scopus subject areas
- Organic Chemistry