Structural effects on metalloporphyrin redox potentials. Electroreduction of mono-N-hexadecylpyridiniumporphyrins in non-aqueous media
✍ Scribed by K.M. Kadish; Y.H. Liu; D. Sazou; N. Senglet; R. Guilard
- Book ID
- 102623664
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 452 KB
- Volume
- 251
- Category
- Article
- ISSN
- 0003-2670
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✦ Synopsis
The electroreduction of three N-hexadecylpyridiniumporphyrins in non-aqueous media is reported. The investigated complexes are represented as [(HpyP)H,)+ and [(HpyP)M]+ where M = Cu(II) or VO and HpyP = 5-(4/-Nhexadecylpyridinium)-10,15,20-triphenylporphyrin bromide. Each metalloporphyrin undergoes a reversible two-electron reduction at E,,, values between -0.74 and -0.91 V in pyridine, dimethylformamide
or dichloromethane and is assigned as a simultaneous one-electron addition to the porphyrin x ring system and the N-hexadecylpyridinium substituent.
A second reversible one-electron reduction occurs in the range of -1.64 to -1.83 V and gives a species that is reduced by an overall three electrons, two of which reside on the porphyrin TJ ring system. UV-visible and ESR spectra were obtained during the initial two-electron electroreduction and the resulting data analyzed with respect to the initial site of electron transfer.