2007 Fiscal Year Final Research Report Summary
Construction of Electro-functional Space Using Interfacial Bottom-up Synthesis of Coordination Bond Network
| Project/Area Number |
16074204
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
NISHIHARA Hiroshi The University of Tokyo, Graduate School of Science, Professor (70156090)
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| Co-Investigator(Kenkyū-buntansha) |
YAMANOI Yoshinori The University of Tokyo, Graduate School of Science, Assistant Professor (20342636)
KUME Shoko The University of Tokyo, Graduate School of Science, Assistant Professor (30431894)
YONEZAWA Tetsu The University of Tokyo, Graduate School of Science, Associate Professor (90284538)
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| Project Period (FY) |
2004 – 2007
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| Keywords | surface properties / nanometerial / micro-nano-device / quantum wire / molecular machine |
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| Research Abstract |
In this project, we aim at the construction of electro-functional interfacial space by assembling pi-conjugated and/or redox active metal complex molecular chains in one, two, or three dimensions. Bottom-up approach using successive coordination bond formation is utilized in order to create the space in which potential distribution can be controlled by external stimuli such as electrons and photons.
Films of linear and branched oligomer wires of Fe (tpy)2 (tpy = 2,2' :6',2" -terpyridine) were constructed on a gold electrode surface by the interfacial stepwise coordination method employing a surface-anchoring ligand, (tpy-C6H4N=NC6H4-S) 2 (1), two bridging ligands, 1,4-C6H4(tpy)2 (3) and 1,3,5-C6H3(C・C-tpy)3 (4), and metal ions. The quantitative complexation of the ligands and FeII ions was monitored by electrochemical measurements in linear oligomers of 3 up to eight complexation cycles and in branched oligomers of 4 up to four cycles. STM observation of branched oligomers at low surface coverage showed an even distribution of nanodots having uniform size and shape, suggesting the quantitative formation of dendritic structures.
The electron transport mechanism and kinetics for the redox reaction of the films of linear and branched oligomer wires were analyzed by potential step chronoamperometry (PSCA). The unique i-t behavior, obtained similarly in all conditions indicates that electron conduction occurs not by diffusional motion but by successive electron hopping between neighboring redox sites within a molecular wire. This is the first observation of redox conduction in a single molecular wire in redox polymer films.
Other studies such as fabrication of Co-Ru wires and anthraquinone-bridged metal complex molecular wires were also reported.
We also constructed a ferrocenylabozenezene SAM which can undergo reversible isomerization with a single green light source and a redox reaction.
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