Intriguing Electrochemical Behavior of Free Base Porphyrins: Effect of Porphyrin鈥?i>meso-Phenyl Interaction Controlled by Position of Substituents on meso-Phenyls

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• 作者：Yi-Jung Tu ; Hsu Chun Cheng ; Ito Chao ; Cheng-Ru Cho ; Ru-Jen Cheng ; Yuhlong Oliver Su
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：February 16, 2012
• 年：2012
• 卷：116
• 期：6
• 页码：1632-1637
• 全文大小：272K
• 年卷期：v.116,no.6(February 16, 2012)
• ISSN：1520-5215

文摘

Electrochemical properties of substituted free base meso-tetraphenylporphyrins (H<sub>2sub>T(o,o鈥?X)PP, H<sub>2sub>T(o-X)PP, and H<sub>2sub>T(p-X)PP, where X = OCH<sub>3sub>, CH<sub>3sub>, H, F, or Cl on the phenyl rings) are examined by cyclic voltammetry. When a substituent is located only at the para position of the meso-phenyl group, the difference between the first and second oxidation potentials (螖E<sup>oxsup>, i.e., E<sub>2sub><sup>oxsup> 鈥?E<sub>1sub><sup>oxsup>), is generally significantly smaller than those of the H<sub>2sub>TPPs with bulky o,o鈥?substituents on the phenyl group. This trend is elucidated with density functional theory calculations and attributed mainly to the sterically controlled 蟺-conjugation of the meso-phenyl groups to the central porphyrin ring, rather than the often discussed deformation of porphyrin.