Abstract: The redox behaviour of porphyrin compounds containing several redox centres(where the porphyrin compound is meso-tetrakis (4-nitrophenyl)-porphyrinatocobalt(Ⅱ), [TNPPCo(Ⅱ)]) was investigated by cyclic voltammetry, in-situ UV-visible and FT-IRspectroelectrochemistry in dimethylformamide(DMF)and dimethylsulfoxide(DMSO).The first oxidation or reduction of TNPPCo(Ⅱ)is that centre metal cobalt(Ⅱ)loses or obtains one electron and leads to the formation of[TNPPCo(Ⅲ)]⁺ or [TNPPCo(I)]^-.The secondreduction of TNPPCo(Ⅱ) is that four nitro groups of nitrophenyl on porphyrin ring meso sites respectively obtain one electron at the same potential and lead to the formation of the corresponding radical anions, and in this step overall porphyrin molecule obtains four electrons and leads to the formation of[TNPPCo(I)]^5-.The third reduction of TNPPCo(Ⅱ) is that the porphyrin ring obtains one electron, but this reaction is irreversible. It was found that the intermolecular electronic interaction occured between nitro groups and porphyrin ring or centre metal cobalt, but the intermolecular electronic interaction among four nitro groups was not found.

Key words: Tetrakis(4-nitrophenyl)-porphyrinatocobalt(Ⅱ), In-situ UV-visible and FT-IR spectroelectrochemistry, Intermolecular electronic interaction