| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1995: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
1 : Intrinsically conductive macromolecules (ICM), possessing a vanishingly small bandgap, is one of the fundamental materials for the development of molecular devices. We have designed novel candidate monomers for ICM ; a series of mixed trimers composed of aromatic heterocycles and a nonclassical thiophene with pyrazine-dihydropyrazine redox system. The oxidized forms of these compounds have much lower optical and electrochemical energy gaps compared to the reduced forms and the related oligomers. Especially the pyrrole derivative possesses the lowest energy gap value (the absorption edge were observed at 2100nm [-0.6eV]) in oligoheterocycles reported so far. The anodic oxidation of the pyrrole derivative gave the electroactive polymer exhibiting a vanishingly small electrochemical energy gap. In order to establish general stategies for bandgap controlling of our systems, we have also investigated the structure-properties relationship of the well-defined model oligomers.
2 : "Well-def
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ined" and "multifunctional" ICM's will be the main components to construct unimolecular electronic devices operating at the molecular level. We have developed a new synthetic approach to "precisely-defined" conjugated highly oligomers with low HOMO-LUMO separation. We have obtained a series of low energy-gap alpha-sexi-and alpha-spetithiophenes constituted of various heterocycles based on this method.
3 : We have developed a new candidate system for molecular wire which have a central conducting core surrounded by an insulator by an insulator mantle. The key heterocycle is 3'4'- [N,N' : N,N'-bis (1,1,4,4, -tetramethyl-1,4-disilatetramethylene) di (amino)] -2,2' : 5', 2"-terthiophene 1. This molecule has bulky groups at the beta-positions of the central thiophene ring. In general such bulky substituents will prevent the coplanar chain-conformations. However, all the experimental data supported a high degree of pi-conjugation over the whole molecule of 1. The theoretical calculations suggest that the rigid and bulky substituents on the central ring of 1 surround the adjacent thiophene rings and stabilize the coplanar chain-conformation. Less
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