Star-burst metallo-supramolecular prisms and coordination polymers with pyramidal ligands

We have recently generated a series of pyramidal host-type ligands based on the cyclotriveratrylene framework. These ligands are in shape and have rigid molecular cavities capable of binding other molecules. They can be incorporated into either discrete or polymeric metal-ligand systems, thus creating metallo-supramolecular assemblies or coordination polymers with specific molecular recognition sites. Thus far, we have characterised a number of transition metal species of these ligands, including discrete polynuclear complexes; chain, grid and 3-D coordination polymers; and metallo-supramolecular assemblies such as [Ag2L2] 2+ capsules and [Ag4L4] 4+ star-burst tetrahedra; giant [Pd6L8]12+ stella octangula structures (pictured), and triply interlocked [2]catenane {[M3(NO3) 3L2]} 2 where M = Co, Zn. We can use host-guest chemistry to manipulate the self-assembly outcome: the star- burst [ A g 4L4 ] 4 + tetrahedron is isolated with acetonitrile guests, but with bulkier glutaronitrile guest molecules a 2-D coordination polymer with 4.82 topology is formed instead. These and other examples will be discussed