| Autor: |
Chen, S.-P., Ejeh, D., Levermore, D., Griffith, H., Bullen, Y., Hosten, C. M., Hambright, P. |
| Zdroj: |
The Journal of Physical Chemistry - Part B; November 5, 1998, Vol. 102 Issue: 45 p9101-9108, 8p |
| Abstrakt: |
Electrochemical and surface spectroscopic techniques are used to investigate the reductive electrochemistry of the water-soluble manganese tetrasulfonatophenyl porphyrin. The electrocehmistry of MnTSPP at a Ag, Au, and Pt electrode and the normal Raman and surface-enhanced Raman scattering spectra of the two redox forms of MnTSPP were studied. Voltammetric studies indicate two reductive peaks at −0.45 and −0.85 V on an Ag electrode. Potential-dependent shifts in the 466 nm UV/vis absorbance band to 432 nm at −0.5 V on a gold minigrid electrode indicate that reduction of the porphyrin central metal from MnIII to MnII occurs at this potential. A 32 cm-1 downshift in the ν4 vibration from 1368 to 1336 cm-1 at −0.5 V is further evidence for the reduction of the metal from the MnIII to the MnII state. The reduction of the porphyrin macrocyclic ring to the radical anion is also observed at −0.8 V. The core-sensitive modes of aquo MnIIITSPP are in excellent agreement with that of a 6-coordinate species. Upon reduction to the MnIITSPP, the core size marker frequencies shift to those of a 5-coordinate species. Finally, Raman band frequencies for the solution and SERS spectra are systematically assigned, and normal Raman and surface-enhanced Raman spectra are presented for MnIIITSPP and its reduced MnIITSPP. |
| Databáze: |
Supplemental Index |
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