Porphyrin complexes with p, d, and f metals in high oxidation states: Structures, electronic absorption, and IR spectra

This paper is a review of data obtained by the authors and of the literatur e data on the molecular structure of porphyrin complexes with p, d, and f m etals in oxidation states from two to five and on complexation as revealed from the absorption spectra of porphyrins in UV, visible, and IR regions. I t was shown that, depending on the type of donor-acceptor bonds, the EAS of metalloporphyrins can be divided into three groups and classified as commo n, hypso, or hyper spectra. The high-frequency or low-frequency shifts of b ands of metal-sensitive porphyrin vibrations in IR spectra of complexes cor relate with the type of electronic spectrum; therefore, they were used to s tudy the electronic aspects of coordination interaction in the porphyrin co mplexes.