Synthetic Expanded Porphyrin Chemistry

Expanded porphyrins are synthetic analogues of the porphyrins, and differ from these and other naturally occurring tetrapyrrolic macrocycles by containing a larger central core with a minimum of 17 atoms, while retaining the extended conjugation features that are a hallmark of these quintessential biological pigments. The result of core expansion is to produce systems with novel spectral and electronic features, interesting and, often unprecedented, cation-coordination properties, and, in many cases, an ability to bind anions in certain protonation states. Also adding to the appeal of expanded porphyrins is their central role in addressing issues of aromaticity. In many cases, they also display structural…