title: Asymmetry of electron transmission through monolayers of helical polyalanine adsorbed on gold surfaces.
abstract: Polyalanine derivatives containing cysteamine linker R-(Ala)14NH-(CH2)2-SH, where R is ferrocenecarbonyl or hydrogen, were synthesized and then used to form self-assembled monolayers on gold. The tilt angles and the packing density of the molecules within monolayer assemblies were determined by FTIR spectroscopy and scanning tunneling microscopy, respectively. Electrochemical properties of monolayer-modified electrodes were studied using cyclic voltammetry and impedance spectroscopy. Measurements of electron-transfer rates using electrochemical techniques and scanning tunneling spectroscopy revealed asymmetry dependent on the applied voltage. It is suggested that the observed electron-transfer behavior is connected with the electric field generated by the molecular dipole of the polyalanine helix.
authors.affiliation: Department of Chemistry, University of Warsaw, Pasteura 1, 02093 Warsaw, Poland. slasek@chem.uw.edu.pl
authors.forename: Slawomir
authors.initials: S
authors.lastname: Sek
authors.forename: Anna
authors.initials: A
authors.lastname: Tolak
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Misicka
authors.forename: Barbara
authors.initials: B
authors.lastname: Palys
authors.forename: Renata
authors.initials: R
authors.lastname: Bilewicz
mesh_terms: D000327:Adsorption; D004583:Electrons; D006046:Gold / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D010455:Peptides; C019529:polyalanine; D006046:Gold