Metal-organic polygons, polyhedra and extended structures: Assemblies arising from products of template-directed synthesis in the solid state

Solid-state synthesis, while able to provide access to molecules that are difficult to otherwise obtain, is not routinely used to generate molecules for applications, owing to difficulties in predicting positioning of reactant molecules within a solid. Template-directed solid-state synthesis is a method whereby template molecules interact with reactant molecules to form discrete assemblies within a crystal. Within these discrete assemblies, reactant molecules are appropriately arranged to undergo [2+2] photodimerization, resulting in a cyclobutane product. This has enabled production of a family of tetrapyridylcyclobutane (tpcb) molecules in quantitative yield and gram quantities. The coordination chemistry of members of this family with transition metals such as Cu(II), Zn(II) and Ag(I) has been systematically studied. Upon metal-mediated self-assembly, the ligands give rise to chelation complexes, metal-organic polygons, polyhedra, infinite frameworks in one and two dimensions, and gels. The assemblies are characterized by X-ray crystallography, as well as in solution by UV-Vis spectroscopy and electrospray mass spectrometry. This is the first time that the coordination chemistry of products from solid state synthesis has been systematically researched.; One tpcb ligand in particular sustains both polygonal and polyhedral metal-organic assemblies. This ability is unique and stems from the unsymmetrical nature of the ligand. Both assemblies have been characterized in solution, and evidence for switching is reported. In addition, a supramolecular approach to exterior functionalization of metal-organic polyhedra is presented and the utility of the approach is demonstrated by the design of chiral polyhedra.; These results demonstrate that molecules derived from template-directed solid-state synthesis can serve as organic building blocks for metal-mediated self-assembly of a diverse array of metal-organic architectures, and that they lead to assemblies that are unique in the field of metallosupramolecular chemistry.