氯离子存在下四苯基卟啉合锰的电化学和现场光谱电化学 Ⅱ.氧化过程

Electrochemical and In-Situ Spectroelectrochemical Study of (Tetraphenylporphinato) manganese (Ⅲ) Perchlorate in the Presence of Chloride Anions Ⅱ. Oxidation Processes

本文研究了氯离子滴定过程中四苯基卟啉合锰氧化过程的常规循环伏安、薄层循环伏安及现场紫外-可见光谱电化学行为。发现在1摩尔比的Cl^-存在下,四苯基卟啉合锰经历了Mn(Ⅲ)/Mn(Ⅲ)环阳离子自由基及进一步氧化为环两价阳离子的过程,并伴随有异卟啉生成的后行化学反应,当2摩尔比的Cl^-存在时,反应机理转变为Mn(Ⅲ)/Mn(Ⅳ),Mn(Ⅳ)/Mn(Ⅳ)环阳离子自由基并伴随有异卟啉生成反应的两个氧化步骤。提出了与这一滴定过程相关的氧化还原反应机理。

An investigation of electrode oxidation processes of(tetra-phenylporphinato) manganese(Ⅲ) Perchlorate, (TPP)Mn(Ⅲ)ClO_4, was carried out during the titration of chloride anions by conventional cyclic voltammetry, thin-layer cyclic voltammetry and spectroelectrochemistry. It was demonstrated that in the presence of one equivalent amount of Cl^-, the first one electron oxidation reaction corresponds to the Mn(Ⅲ)/cation radical oxidation, and the second one electron oxidation corresponds to the cation radical/dication generation followed by an iso-porphyrin formationreaction, however in the presence of two equivalent amount of Cl^-, the first one electron oxidation of Mn(Ⅲ) gives Mn(Ⅳ) porphyrin and the second one electron oxidation generates cation radicals of Mn(Ⅳ) followed by an iso-porphyrin formation reactions. Mechanisms of these redox processes are postulated.