Introduction expanded porphyrins

In spite of what is now an overwhelming body of data supporting the contention that protonated expanded porphyrins can chelate anions in the solid state, it is important to appreciate that, in most instances, the presumed anion-binding properties have yet to be confirmed via what are often more demanding solution-phase analyses. In fact, as mentioned in the introduction to this portion of the chapter (i.e.. Section 10.5.1), only three expanded porphyrin systems, sapphyrin, rubyrin and anthraphyrin, have been established as being bona fide anion-binding agents in solution and only one of these, namely sapphyrin, has been studied in detail. 

Expanded Porphyrins as Anion-binding Agents 10.5.1 Introduction... 

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