Photoinduced electroreduction of chlorophyllide on alkanethiol-coated mercury.
Monolayers of n-alkanethiols of chain length from C12 to C18 were self-assembled on a hanging mercury drop electrode, and a film of chlorophyllide (Chlide) was adsorbed on top of them. The reduction photocurrents following illumination of the Chlide film were measured over the potential range in which the Chlide is electroinactive in the dark, and their action spectra were determined. Plotting the derivative of the photocurrents with respect to the applied potential against potential yields bell-shaped curves that can be fitted to a Gaussian. The potential of the Gaussian maximum was used to determine the reorganization energy lambda for the Chlide electroreduction process. An increase in the thiol chain length causes lambda to decrease regularly and the photocurrent to decay exponentially with the monolayer thickness, with a decay constant beta of about 0.17 A(-1).
Tadini Buoninsegni
Francesco
F
Departments of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy.
Moncelli
Maria Rosa
MR
Aloisi
Giovanni
G
Agostiano
Angela
A
Guidelli
Rolando
R
D040761:Biomimetic Materials / Q000737:chemistry; D002735:Chlorophyllides / Q000737:chemistry*; D008628:Mercury / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry*
D002735:Chlorophyllides; D013438:Sulfhydryl Compounds; D008628:Mercury