Distance Dependence of the Electron Transfer Rate through Oligoglycine Spacers Introduced into Self-Assembled Monolayers

Sęk, Sławomir; Sepiol, Anna; Tolak, Anna; Misicka, and Aleksandra; Bilewicz, Renata

doi:10.1021/jp049116y

Cited by 62 publications

(54 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such observations appear best in keeping with a hopping mechanism, which is, however, again hard to accord with the nucleobase redox levels that would be involved. Bilewicz and associates (64) and Tao and associates (60), however, reported a much stronger, approximately exponential distance dependence of the interfacial electrochemical peptide-mediated rate constant and the single-molecule peptide conductivity, respectively, much better in accord with a superexchange conductivity mode.…”

Section: Discussionmentioning

confidence: 96%

In situsuperexchange electron transfer through a single molecule: A rectifying effect

Kornyshev

Кузнецов

Ulstrup

2006

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

An increasingly comprehensive body of literature is being devoted to single-molecule bridge-mediated electronic nanojunctions, prompted by their prospective applications in molecular electronics and single-molecule analysis. These junctions may operate in gas phase or electrolyte solution (in situ). For biomolecules, the latter is much closer to their native environment. Convenient target molecules are aromatic molecules, peptides, oligonucleotides, transition metal complexes, and, broadly, molecules with repetitive units, for which the conducting orbitals are energetically well below electronic levels of the solvent. A key feature for these junctions is rectification in the current-voltage relation. A common view is that asymmetric molecules or asymmetric links to the electrodes are needed to acquire rectification. However, as we show here, this requirement could be different in situ, where a structurally symmetric system can provide rectification because of the Debye screening of the electric field in the nanogap if the screening length is smaller than the bridge length. The Galvani potentials of each electrode can be varied independently and lead to a transistor effect. We explore this behavior for the superexchange mechanism of electron transport, appropriate for a wide class of molecules. We also include the effect of conformational fluctuations on the lowest unoccupied molecular orbital (LUMO) energy levels; that gives rise to non-Arrhenius temperature dependence of the conductance, affected by the molecule length. Our study offers an analytical formula for the current-voltage characteristics that demonstrates all these features. A detailed physical interpretation of the results is given with a discussion of reported experimental data.tunneling junction ͉ molecular rectifier S tudies of bridge-assisted electron transfer (ET) processes have a long history. The mechanism of inner-sphere ET between transition-metal complexes through ligands was introduced by Taube et al. (1,2) and Halpern and Orgel (3). McConnell (4) rationalized this idea on the basis of high-order perturbation theory. Quantum theory of bridge-assisted ET in polar solvents and electrode͞electrolyte interfaces was systematically developed in the 1970s and 1980s for chemical (refs. 5-13; for review of quantum chemistry aspects of the problem, see ref. 14), biochemical (15, 16), and electrochemical (17) reactions.Bridge-assisted ET has reattracted strong interest in the last decade in relation to studies of long-distance ET through single molecules, including biological molecules such as proteins and DNA. New kinds of experimental studies in this area have become possible because of progress in solid-state nanojunctions and electrochemical in situ scanning tunneling microscopy (18). A voluminous body of literature has been devoted to the theory of nanojunctions with focus on potential applications in molecular electronics or as new diagnostic tools (for reviews, see refs. 19-25). Three major mechanisms are presently in focus: electron hopping (...

show abstract

Section: Discussionmentioning

confidence: 96%

In situsuperexchange electron transfer through a single molecule: A rectifying effect

Kornyshev

Кузнецов

Ulstrup

2006

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…The distancedependent charge transfer of the thymine (T) containing PNA SAMs had a tunneling decay constant similar to that of peptide linkages, 79,80 ) 0.86 ( 0.04 Å -1 . Using this value and extrapolating to zero distance, i.e., to contact between ferrocene and the electrode, provides a maximum electron-transfer rate constant of 5.8 × 10 8 s -1 .…”

Section: Dicussion and Conclusionmentioning

confidence: 96%

Charge Transfer through Single-Stranded Peptide Nucleic Acid Composed of Thymine Nucleotides

et al. 2008

View full text Add to dashboard Cite

Self-assembled monolayers (SAMs) of single-stranded peptide nucleic acids (PNAs) containing 3 to 7 thymine (T) nucleotides, a C-terminus cysteine, and an N-terminus ferrocene group were formed on gold electrodes. The existence of two redox environments for the ferrocene was detected by cyclic voltammetry and was attributed to the presence of "lying-down" and "standing-up" PNA molecules. By exploiting the chemical instability of the ferrocenium ion, electrochemical cycling was used to destroy the ferrocene of "lying-down" molecules while keeping the ferrocene in the "standing-up" molecules intact. Electrochemical measurements were used to determine the electron-transfer rate through the "standing-up" PNA molecules. The tunneling decay constant for these SAMs was determined to be about 0.9 Å -1 . IntroductionThe interest in self-assembled monolayers (SAMs) 1,2 of nucleic acids has increased recently, largely because of their potential applications in molecular electronics, 3 materials science, 4 molecular recognition, 5 biotechnology, and biosensor development. [6][7][8] An understanding of the charge transport (CT) through such SAMs is needed to realize their potential in molecular electronics and biosensing. The past decade has seen progress in understanding charge transfer through deoxyribonucleic acid (DNA), which is believed to occur through either a superexchange mechanism, 9-19 which dominates at short distances, or a hopping mechanism, 20-25 which dominates at large distances.The weak distance dependence of the charge hopping mechanism and its prevalence in duplex DNA systems have motivated the exploration of charge transfer through DNA and its promise for molecular electronics by a large number of different research groups. Nevertheless, only a few research groups have studied CT in DNA monolayers, probably because of the difficulties in creating well-defined DNA assemblies on a metal surface. [26][27][28] For example, Hartwich et al. 29 used cyclic voltammetry to characterize charge transfer in mixed monolayers of DNA having a pyrroloquinoline-quinone redox probe attached to DNA through a spacer and linked to an Au(111) surface through an ethane-thiol linker. These studies determined that the CT rate constant for a 12-base-pair (bp) DNA duplex was 1.5 s -1 , while for the same duplex containing two mismatches it was 0.6 s -1 , and that charge transfer could not be detected for single-stranded (ss) DNA at a scan rate of >10 mV s -1 . Liu et al. 30 argued that CT through a monolayer of a 30-bp double-stranded (ds) DNA takes place through the nucleobase stack and does not involve the DNA backbone. They based their argument on the fact that the rate constant for CT of 30 s -1 was not affected by breaks in the sugar-phosphate backbone and was too small to be measured when a mismatch was introduced in the ds DNA. Interestingly, a similar rate constant for CT was measured for a monolayer of a 15-bp ds DNA. 31 CT rate constants for ss oligonucleotides are also quite high. For example, Kraatz and collaborators r...

show abstract

“…In all aforementioned cases, the efficient action of such systems involves the use of the molecules with specific, well-defined electronic conductance. It is known that peptides can act as mediating bridges for long range electron transfer and the efficiency of this process may be affected by the details of the amino acid sequence, the secondary structure of the peptide and the presence of the hydrogen bonds [6][7][8][9][10][11]. Thus the fundamental problem is how to design the suitable functional molecule to attain desired structure and the electronic conductance.…”

Section: Introductionmentioning

confidence: 99%

Peptide molecular junctions: Electron transmission through individual amino acid residues

Juhaniewicz

Sęk

2010

Journal of Electroanalytical Chemistry

Self Cite

View full text Add to dashboard Cite

Distance Dependence of the Electron Transfer Rate through Oligoglycine Spacers Introduced into Self-Assembled Monolayers

Cited by 62 publications

References 40 publications

In situsuperexchange electron transfer through a single molecule: A rectifying effect

In situsuperexchange electron transfer through a single molecule: A rectifying effect

Charge Transfer through Single-Stranded Peptide Nucleic Acid Composed of Thymine Nucleotides

Peptide molecular junctions: Electron transmission through individual amino acid residues

Contact Info

Product

Resources

About