Photoinitiated ion movements in bilayer membranes containing magnesium octaethylporphyrin

摘要: A photocurrent produced by planar lipid bilayers containing Mg-octaethylporphyrin in the presence of oxygen has been investigated to determine if current is due movement MgOEP+ ion bilayer. Photoexcitation MgOEP known produce bilayer when an electron acceptor present. However, aqueous acceptors ferricyanide and methyl viologen (MV+2) have opposite effects on photocurrent. Ferricyanide decreases photo current, even oxygen, whereas increases photocurrent, but only We attribute most superoxide anion. The difference effect between attributed different rates reduction O2 reduced MV+ (fast) vs. ferrocyanide (slow) competition as for photoexcited porphyrin. It inferred that localized polar region Addition phase one side bilayer, trap other MV+2, fails increase lifetime photovoltage. With a pH gradient across we observed 5% photovoltage expected selective transport H+ or OH- MgOEP+. Thus, these measurements set lower limit cross transit time its charge range 0.1–0.5 s.