Self-assembly in supramolecular systems

The complex structural and functional properties of many natural molecules have spawned innumerable attempts to understand and mimic biological activity. This has often involved preparing extremely complex structures of carefully designed geometries. In natural systems the primary structure of a protein (the amino acid sequence) establishes all of the structural relationships within the molecule, although many of these are not apparent until the molecule folds, coils, or otherwise adopts the appropriate conformation. Nature has selected suitable amino acid sequences for various applications during eons of evolution. In this paper, we report our efforts to achieve similar results by providing all of the required structural elements on a flexible framework. This concept is illustrated in three ways: the design and preparation of a redox-switched vesicle and a small-molecule molecular receptor (both based on the ferrocene system) and of a functional cation channel.