Voltammetry of Mn(III) Porphyrin in Trihexyl(tetradecyl)‐phosphonium Tris(pentafluoroethyl)trifluorophosphate Supported Toluene in Contact with an Aqueous Electrolyte

Voltammetry of manganese tetraphenylporphyrinato chloride in trihexyl(tetradecyl)phosphonium tris(pentafluoroethyl)trifluorophosphate solution in toluene reveals its unexpectedly low diffusion coefficient. UV‐vis spectra confirm significant Cl^? exchange with large phosphate anion at the axial position of the complex. Experiments performed with a glassy carbon electrode covered by a liquid film of the same solution and immersed in an aqueous electrolyte solution show a peak potential dependence on the nature and concentration of the aqueous electrolyte anion described by a Nernst type equation. Electron transfer is followed by anion expulsion where the anion effect results from the lability of the axial coordination site of the porphyrin and from spontaneous ion exchange.