Raman spectra of platinum hematoporphyrin complexes

The laser Raman spectra of the solid hematoporphyrin free-base H2Hem, the diacid, [H4Hem]2+ and the platinum complexes, [H4Hem]2+ [PtCI4]2−, the Sitting-Atop complex (SAT), cis-Pt(H2Hem) Cl2 and the platino-hematoporphyrin PtHem have been studied in the range 500 to 1800 cm−1. The spectra of the platinum complexes are significantly different from those of hematoporphyrin and changes of the band profiles upon incorporation of the platinum atom into the porphyrin plane are shown. An interesting change is observed in the series H2Hem cis-Pt(H2Hem) Cl2 PtHem in the region 1300–1650 cm−1. The Raman lines in this region are normally assigned to the vibrational modes of CC and CN. The Raman spectra provide another evidence of the existence of the SAT complex.