Synthesis and Structural Characterization of Corrole and Sapphyrin Analogs of Imidazolium-Pyridine Cyclophanes

Dissociation of metals from medicinal agents and deposition in healthy tissue is a major problem with many metal-based pharmaceuticals. N-heterocyclic carbenes have been shown to complex more strongly than do phosphines to a variety of metals. By incorporating N-heterocyclic carbenes into the structure of a multi-donor ligand, we envision the resulting moiety to be able to retain the metals better than other ligands. We report the synthesis of three novel mixed donor imidazolium salts. The two imidazolium cyclophanes have the potential to coordinate and stabilize metals of ­various sizes into their inner cavity.