Expanded porphyrins. Synthetic materials with potential medical utility
A number of aromatic and nonaromatic expanded porphyrins have been prepared in the authors' laboratories. These are allowing a number of important themes to be explored, including the construction of novel cation- and anion-complexing agents and the generation of drug candidates with considerable therapeutic potential. In this paper, the use of gadolinium(III) and lutetium(III) texaphyrin derivatives as, respectively, adjuvants for X-ray radiation cancer therapy and photosensitizers for use in photodynamic treatments of cancer, atheromatous plaque, and age-related macular degeneration will be reviewed. Also discussed are the use of water soluble sapphyrins as potential fluorescent phosphate sensors and organic soluble 2,3- dipyrrylquinoxaline derivatives as possible fluoride anion signaling agents. Recent synthetic work, designed to produce expanded porphyrins with new shapes and novel topologies, is also summarized.