Effects of axial ligands on the electron transfer catalyzed by manganese tatrakis(pentafluorophenyl)porphyrin in poly(γ‐methylL‐glutamate) membrane

摘要

AbstractPoly(γ‐methylL‐glutamate) (PMLG) membrane containing manganese tetrakis(pentafluorophenyl)porphyrinSystematic name: Tetrakis(pentafluorophenyl)porphyrinatomanganese.(MnPFPP) has been studied for the transmembrane redox reaction between dithionite and ferricyanide in separated solutions. The effects of the ligand species, namely, OH−, Cl−, imidazole (Im), pyrazine (Pyz), triethylamine (TEA), and pyridine (Py), on the electron transfer rate in the membrane were examined. UV/VIS spectroscopy and sorption measurements confirm that these ligands are sorbed by the membrane from the external buffer solution and coordinate to MnPFPP. With the membrane containing 160 μmol · g−1of MnPFPP, the apparent rate factor, estimated as the pseudo‐first‐order rate constant of the bleach of ferricyanide times membrane thickness, follows the order Im ≫ Cl−Pyz>TEA, OH−, Py>0, suggesting that Im, Cl−and Pyz are effective ligands for the electron transfer. Such a ligand‐specific transfer stems from the electron‐transferability of