Spectroscopic Studies of the Simpler Porphyrins I. The Absorption Spectra of Porphin, ms-Methyl Porphin, ms-Ethyl Porphin, ms-Propyl Porphin and ms-Phenyl Porphin

The molecular absorption coefficients of porphin and four ms-substituted porphins have been measured throughout the visible region and the curves showing absorption coefficient as a function of wave-length are shown. All of the substances have a very strong absorption band at the violet end of the visible region. The rest of the spectrum, while similar in pattern for all of the substances, shows some characteristic differences.