Chelation effects in the binding of bidentate ligands by a face-to-face zinc porphyrin

Abstract

The face-to-face zinc porphyrin (2) is a selective host for 4,4′- bipyridyl as compared with the diamines H₂N(CH₂)_nNH₂. This selectivety arises from a much higher chelation factor (14M) for the bipyridyl guest as compared with the very low factors (M) for the diamines. These results are discussed in terms of host and guest structures and compared with other host–guest systems.