Field and chirality effects on electrochemical charge transfer rates: spin dependent electrochemistry.
This work examines whether electrochemical redox reactions are sensitive to the electron spin orientation by examining the effects of magnetic field and molecular chirality on the charge transfer process. The working electrode is either a ferromagnetic nickel film or a nickel film that is coated with an ultrathin (5-30 nm) gold overlayer. The electrode is coated with a self-assembled monolayer that immobilizes a redox couple containing chiral molecular units, either the redox active dye toluidine blue O with a chiral cysteine linking unit or cytochrome c. By varying the direction of magnetization of the nickel, toward or away from the adsorbed layer, we demonstrate that the electrochemical current depends on the orientation of the electrons' spin. In the case of cytochrome c, the spin selectivity of the reduction is extremely high, namely, the reduction occurs mainly with electrons having their spin-aligned antiparallel to their velocity.
†Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
Prakash Chandra
PC
Mondal
†Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.|‡Department of Chemical and Geological Science, University of Modena and Reggio Emilia, Via G. Campi 183, 41125 Modena, Italy.
Claudio
C
Fontanesi
§Department of Chemistry, Pittsburgh University, Pittsburgh Pennsylvania 15260, United States.
David H
DH
Waldeck
†Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
Ron
R
Naaman
chirality; cysteine; cytochrome c; self-assembled monolayers; spin