Methyl viologen mediated oxidation-reduction across dihexadecylphosphate vesicles involves transmembrane diffusion

Journal Article · Wed May 25 04:00:00 EDT 1988 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00219a050· OSTI ID:7076943

Patterson, B C; Thompson, D H; Hurst, J K

Numerous reports have appeared describing oxidation-reduction across bilayer membranes. Mechanisms proposed for specific systems include the following: (i) electron tunneling across the hydrocarbon barrier between interfacially bound redox partners, (ii) molecular diffusion of bound redox components across the barrier, and (iii) formation of barrier-penetrating aggregates, or electron-conducting channels, across the bilayer. Nonetheless, the actual reaction mechanisms remain obscure due to the general unavailability of transverse diffusion rates, possible loss of compartmentation of reactants, particularly in photochemical systems, and the ambiguities inherent in deducing reaction mechanisms from rate data, which form the primary evidence in most systems studied. The reactions of dihexadecylphosphate (DHP) vesicle-bound methyl viologen (MV/sup 2 +/) describes in this report are unique in allowing deduction of molecular details of a transmembrane redox event from the product composition and microphase distribution. Specifically, they have found that MV/sup 2 +/ bound at the outer vesicle interface mediates reduction of inner-localized MV/sup 2 +/ by dithionite ion in bulk solution in a manner that requires comigration of MV/sup +/ with the electron transferred across the membrane barrier.

• Research Organization: Oregon Graduate Center, Beaverton, (USA)
• DOE Contract Number: FG06-87ER13664
• OSTI ID: 7076943
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 110:11; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
AZINES
BIPYRIDINES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
DIFFUSION
ELECTRON TRANSFER
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
KINETICS
MEMBRANES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
REACTION KINETICS
REDOX REACTIONS