Solution structure of porphyrin aggregates determined by 1 H NMR ring current shifts. I. Heterodimers of oppositely charged porphyrins

The solution structures of dimers consisting of negatively charged Zn[tetra(4‐carboxyphenyl)porphyrin], ZnTPPC, with positively charged Zn[tetra(4‐ N ‐methylpyridyl)porphyrin], ZnTMPyP, and with H 2 [tetra(4‐ N ‐methylpyridyl)porphyrin], H 2 TMPyP, were determined by 1 H NMR ring current shifts. The conformation is not affected by the presence of the metal in the centre of the TMPyP monomer. The dimers have a cofacial conformation with a plane‐to‐plane separation of 3.1 Å and an in‐plane translation of 4.2 Å along the aryl—aryl axis.