Infrared spectra porphyrins

In 1984, Groves and Quinn reported the formation of a trans-dioxo-ruthenium(VI) porphyrin complex (5) by the reaction of Ru (TMP)CO with either mCPBA or iodosylbenzene [168]. 5 is stable even at room temperature as a diamagnetic compound, thus, NMR spectrum of 5 can be readily available to characterize the structure. The infrared spectrum of 5 showed a strong band at 821 cm" assigned to vru=0 [168]. The most interesting feature of 5 is aerobic epoxidation of olefins, i.e., in the presence of 5, olefins are oxidized by consuming O2 [169]. Further, they found Ru(II) porphyrins catalyzed the cis-trans isomerization of epoxides under mild conditions [170]. Che et al also prepared tr n.s-dioxo-Ru (OEP) complexes in the reaction of Ru (OEP)CO and... 

The metalloporphyrin V-cation radical spectrum. An extremly broad band covering the whole visible range of the spectrum and often extending into the near infrared is typical of a one-electron oxidation product of the porphyrin ligand. Sometimes strong visible absorption bands around 700 nm are also found with these products, but the broad visible absorptions are always present. The Soret band usually has a low extinction coefficient and is broadened considerably [e.g. Fuhrhop (76)]. 

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