Authors: Y. Arikuma, H. Nakayama, T. Morita, S. Kimura
Affilation: Kyoto University, Japan
Pages: 143 - 146
Keywords: electron transfer, helical peptide, self-assembly, hopping mechanism
We have studied long-range electron transfer through various lengths of helical peptides from 8 mer (24 Å) up to 80 mer (120 Å) in self-assembled monolayers prepared on a gold surface. Helical peptides carrying a redox-active ferrocene unit and a disulfide group at the respective terminals were synthesized and immobilized on gold via a gold-sulfur linkage to form a well-defined monolayer with vertical helix orientation, and the electron transfer from the ferrocene unit to gold through the helical peptides was studied by electrochemistry. The electron transfer showed a very shallow distance dependence and high activation energies, both of which are characteristic of a hopping mechanism. Detailed theoretical calculations successfully demonstrated that a hopping mechanism with the amide groups as hopping sites is responsible for the long-range electron transfer, which enables ultralong-range electron transfer over 120 Å with the 80 mer helical peptide.