含多个氧化还原中心的卟啉化合物的电化学及光谱电化学行为(Ⅰ)

在DMF及DMSO中用循环伏安法、现场紫外可见光谱电化学方法及现场FT-IR光谱电化学方法研究了含多个氧化还原中心的卟啉化合物四(对-硝基苯基)卟啉合钴(Ⅱ)]的氧化还原性质。指出该化合物的第一步氧化或第一步还原为中心金属钴失去或得到1个电子；第二步还原为卟啉环meso位的4个对硝基苯基上的硝基在同一电位下各得1个电子,形成相应的阴离子自由基；第三步还原为卟啉环得到1个电子,但该步反应不可逆。同时发现硝基与卟啉环及中心金属钴之间存在分子内电子相互作用,而4个硝基取代基之间未发现分子内电子相互作用。

Electrochemical and Spectroelectrochemical Behaviour of Porphyrin Compounds Containing Several Redox Centres(Ⅰ)

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 ofTNPPCo(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 ofTNPPCo(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.