2005 Fiscal Year Final Research Report Summary
Control of Electron Transfer through Molecular WireBased on Molecular Dipole Engineering
| Project/Area Number |
15350068
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Polymer chemistry
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| Research Institution | Kyoto University |
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Principal Investigator |
KIMURA Shunsaku Kyoto University, Graduate School of Engineering, Professor, 工学研究科, 教授 (80150324)
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| Project Period (FY) |
2003 – 2005
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| Keywords | helical peptide / electron transfer / molecular device / molecular memory / self-assembled monolayer / photocurrent generation / STM / dipole |
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| Research Abstract |
1.12-Residue helical peptides were immobilized on gold via N terminal with vertical orientation. STM observation revealed that bright images were identified under bias of -1.3 V, but they disappeared upon applying bias of 1.5 V. The change of the brightness is due to the helix interconversion between 3_<10> helix and a helix, which was induced by interaction of the helical dipole moment with the electric field applied to the helical peptide.
2.25-Residue helical peptide with a crown ether unit at C terminal was synthesized, and the monolayer was prepared on aqueous solution of Ph(NO_3)_2. Pb2+ ions formed complex with the crown ether units, and the monolayer was successfully transferred on gold. After treating the membrane with H_2S, 2-dimensional network of PbS was formed. The thickness of the membrane was 2.4Å showing a wide band gap with a semiconductor property.
3.18-Residue helical peptides with a ferrocene unit at C terminal were synthesized, and their self-assembled monolayers wer
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e formed on gold. The electron transfer reactions in a long rage were evaluated by chronoamperometry to obtain the transfer rates through helical peptides. The interface between the peptide and gold is considered to be one of the rate-determining steps in the electron transfer reaction.
4.16-Residue helical peptides were immobilized on gold with vertical orientation, and the molecular conductance was determined by STS measurements. The I-V curve was analyzed by Simons model, and the attenuation coefficient of the electron transfer was determined to be 0.75Å^<-1>. The helical peptide with a ferrocene unit showed rectification in the I-V curve.
5.16-Residue helical peptides with an N-ethyl carbazolyl group at C terminal were synthesized, and their self-assembled monolayers were prepared on gold. The effect of ionization of the C terminal carboxyl group on the electron transfer through the helical peptide was studied. The molecular system demonstrated that the photocurrent was switched by changing the pH of the solution. Less
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