Distance dependence of the charge transfer rate for peptide nucleic acid monolayers.
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.
Paul
Amit
A
Department of Chemistry, University of Pittsburgh, Pennsylvania 15260, USA.
Watson
Richard M
RM
Wierzbinski
Emil
E
Davis
Kathryn L
KL
Sha
Allen
A
Achim
Catalina
C
Waldeck
David H
DH
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
D005296:Ferrous Compounds; D000075163:Metallocenes; D020135:Peptide Nucleic Acids; D006046:Gold; D003545:Cysteine; C004998:ferrocene