Terpyridine-based building blocks have been used by researchers in the USA and China to form 3D self-assembled spoked wheel-like assemblies. Chrys Wesdemiotis, George R. Newkome, and their team at the University of Akron, Texas State University, and the Beijing Institute of Technology had previously developed a 2D wheel by using a single hexakis(terpyridine) core surrounded by six rim units. In the 3D version, the core is replaced by two staggered tris(terpyridine) units, which stack above and one below the plane of the molecule.
The rim and core ligands were synthesized from brominated precusors by using Suzuki cross-coupling reactions, and β-glucose units were attached to the ligands to increase the solubility of the complexes. The spoked wheel-like product self-assembles in near quantitative yield when stoichiometric amounts of the ligands and zinc(II) ions are mixed, and the structure was confirmed by using mass spectrometry, NMR techniques, and TEM imaging.
This method has potential for use in the one-step self-assembly of complex architectures.
- Self-Assembly of a Supramolecular, Three-Dimensional, Spoked, Bicycle-like Wheel,
Xiaocun Lu, Xiaopeng Li, Yan Cao, Anthony Schultz, Jin-Liang Wang, Charles N. Moorefield, Chrys Wesdemiotis, Stephen Z. D. Cheng, George R. Newkome,
Angew. Chem. Int. Ed. 2013, 52, 7728–7731.