Photochemical electron transfer between methylene blue and quinones
Document Type
Article
Publication Date
1-1-1994
Abstract
Methylene Blue is a well known photochemical oxidant. In this paper we present results of cyclic voltammetry and laser flash photolysis experiments which demonstrate that Methylene Blue may function also as a photochemical reductant. Laser flash photolysis studies of Methylene Blue were carried out in aqueous solution at pH 10, in ethanol and in aqueous dispersions of lipid vesicles in the presence of benzoquinol, benzoquinone and the long-chain naphthoquinone Vitamin K1. Both the quinones and the quinol affected the transient of the decay of triplet Methylene Blue to its ground electronic state. The transients were biphasic and characteristic of an initial electron transfer reaction between triplet Methylene Blue and the quinone or quinol, followed by back electron transfer between the products. For Vitamin K1 and Methylene Blue in ethanol the back electron transfer was very slow (lifetime about 4 ms). This slow back electron transfer is favourable to the use of this system for energy storage via photosynthetic solar energy conversion.
Keywords
Agents Aromatic compounds Electron energy levels Ethanol Lipids Photolysis Solutions Vitamins Benzoquinol Cyclic voltammetry Electron transfer Laser flash photolysis Methylene blue Naphthoquinone Quinones Olefins
Divisions
CHEMISTRY
Publication Title
Australian Journal of Chemistry
Volume
47
Issue
2