Normal coordinate analysis of porphin and its derivatives based on the solution of the inverse spectral problem for porphin and Cu porphin—III. Interpretation of vibrational spectra of metal complexes of octamethylporphin and octaethylporphin

Abstract

The valence force field obtained for Cu porphin from the solution of the inverse spectral problem is used for calculating normal vibrations of Cu octamethylporphin and Cu octaethylporphin and their isotope-substituted derivatives ( 1H- 2H, 14N- 15N). The interpretation of vibrational spectra of octamethylporphin and octaethylporphin metal complexes is given. Insufficient presentation of vibrational modes in terms of potential energy distribution to predict isotope shifts of vibrational frequencies is noted.