title: Distance dependence of the charge transfer rate for peptide nucleic acid monolayers.
abstract: Charge transfer studies have been performed for self-assembled monolayers of single-stranded and double-stranded peptide nucleic acids (PNAs) having a C-terminus cysteine and an N-terminus ferrocene group as a redox reporter. The decay of the charge transfer rate with distance was strong for short single-stranded PNA molecules and weak for long single-stranded and double-stranded PNAs. Possible mechanisms for this "softening" of the distance dependence are discussed. The nature of the mechanism change can be explained by a transition of the charge transport mechanism from superexchange-mediated tunneling for short PNAs to a "hopping" mechanism for long PNAs.
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pennsylvania 15260, USA.
authors.forename: Amit
authors.initials: A
authors.lastname: Paul
authors.forename: Richard M
authors.initials: RM
authors.lastname: Watson
authors.forename: Emil
authors.initials: E
authors.lastname: Wierzbinski
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Davis
authors.forename: Allen
authors.initials: A
authors.lastname: Sha
authors.forename: Catalina
authors.initials: C
authors.lastname: Achim
authors.forename: David H
authors.initials: DH
authors.lastname: Waldeck
mesh_terms: D003545:Cysteine / Q000737:chemistry; D004563:Electrochemistry; D004566:Electrodes; D004579:Electron Transport; D005296:Ferrous Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D007700:Kinetics; D000075163:Metallocenes; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D010084:Oxidation-Reduction; D020135:Peptide Nucleic Acids / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D005296:Ferrous Compounds; D000075163:Metallocenes; D020135:Peptide Nucleic Acids; D006046:Gold; D003545:Cysteine; C004998:ferrocene