Electronic Spectra of Manganic Mesoporphyrin IX Dimethyl Ester

Low intensity overlapping absorption bands in the 12,000 -16,000 cm⁻¹ range of hydroxymanganic mesoporphyrin IX have been resolved by analog computer analyses. Comparison of the bands predicted by ligand field theory with the results of the analysis produced reasonably good evidence that the bands are ligand field bands of the central metal ion. Furthermore, it is found that the porphyrin is a weak field ligand probably in range of the aquo group in the spectrochemical series at least in the case of Mn (III).