Solid-state Porphyrin Interactions with Oppositely Charged Peripheral Groups.

The crystallization and the crystal and molecular structure of a very slightly soluble electrostatically interacting pair of porphyrins is described. The tetra-anion 5,10,15,20-tetrakis-(4-sulfonatophenyl)-21,23H-porphyrin [H2TPPSO3]4- and the tetra-cation 5,10,15,20-tetra(N-methylpyridyl)21H,23H-porphyrin [H2TMePyP]4+ are found to form an alternating one-dimensional stack that is stabilised by electrostatic interactions between the porphyrin rings but also by π-π interactions between all substituted phenyl rings in the ensemble. The resulting interactions between the porphyrins is exceptionally tight.