Abstract The nature of the metalloporphyrin-ligand complexes produced by zinc, magnesium and cobalt porphyrins with basic ligands has been investigated using the diamagnetic ring current shifts of the porphyrin on the ligand protons. The metal to nitrogen bond lengths in some metallo-meso-tetraphenylporphyrin (pyridine) complexes have been determined and compared with the data of the crystalline complexes. The geometry of the Zn meso- ...
