In this study, the electrochemical behavior of zinc meso-substituted porphyrins in the presence of imidazole is examined by using both cyclic voltammetry (CV) and density functional theory (DFT) methods. The results show that the first half-wave oxidation potentials (1st E_1/2) of zinc porphyrins complexed with imidazole all move to the negative side, while the second ones (2nd E_1/2) move to the positive side, resulting in larger half-wave oxidation potential splittings of the two oxidation states (ΔE = second E_1/2 – first E_1/2) comparing with the zinc porphyrins. By employing DFT calculations, we have found that both sterically controlled inter π-conjugation between porphyrin rings and meso-substituted phenyl groups and deformation of porphyrin rings do play important roles in contributing to the half-wave oxidation potentials. Imidazole exhibits strong effects on the deformation of porphyrin rings which is dominant in determining the first E_1/2 while the inter π-conjugation between porphyrin rings and meso-substituted phenyl groups mainly contributes to the second E_1/2. Without imidazole, the inter π-conjugation between porphyrin rings and meso-substituted phenyl groups is the only important criterion which effects both first E_1/2 and second E_1/2 of zinc porphyrins.

中文翻译：

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咪唑对锌卟啉电化学的影响：电化学和计算研究

在这项研究中，通过使用循环伏安法（CV）和密度泛函理论（DFT）方法，研究了咪唑存在下锌介孔取代的卟啉的电化学行为。结果表明，与咪唑配合的锌卟啉锌的第一半波氧化电势（1st E _1/2）均向负侧移动，而第二半波氧化电势（2nd E _1/2）向正侧移动，导致两种氧化态的较大的半波氧化势分裂（ΔE =第二E _1/2 –第一E _1/2）与锌卟啉进行比较。通过使用DFT计算，我们发现卟啉环与内消旋取代的苯基之间的空间控制的π共轭和卟啉环的变形在促进半波氧化电位中都起着重要的作用。咪唑对卟啉环的变形表现出强烈的影响，这在确定第一个E _1/2时起主要作用，而卟啉环与内消旋取代的苯基之间的π共轭主要是对第二个E _1/2的贡献。如果没有咪唑，则卟啉环和内消旋取代的苯基之间的π共轭是影响前两个E _1/2的唯一重要标准和第二E _1/2的卟啉锌。