Manganese Porphyrin-Mediated Electron Transfer across a Liposomal Membrane and on an Electrode Modified with a Lipid Bilayer Membrane

Abstract

Phospholipid-linked mesoporphyrins separated by spacer methylene groups (Cn), PE-Cn-MnMPMME (n = 0, 5, 11) (Chart 1) were synthesized. Manganese porphyrin-mediated electron transfers across a liposomal membrane and on a glassy carbon (GC) electrode covered with a phospholipid bilayer membrane were examined to provide insight into the effect of the structure of porphyrins on these electron transfers between porphyrins in lipid bilayers. Enhanced transmembrane electron transfers catalyzed by phospholipid-linked manganese porphyrin derivatives separated by spacer methylene groups (Cn)(n = 0, 5, 11) (Chart 1) were observed in a liposomal membrane only above the phase temperature of the membrane, depending on the length of the Cn and on the structure of the porphyrins. Furthermore, cyclic voltammetry on a SnO2 glass electrode or on a GC electrode modified with a DPPC membrane containing manganese porphyrins showed that one set of waves was clearly visible corresponding to the consecutive monoelectronic reducti...