1996 Fiscal Year Final Research Report Summary
Synthesis and Properties of Orgamic Molecules with Small HOMO-LUMO Gaps
| Project/Area Number |
07454170
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Organic chemistry
|
|---|
| Research Institution | Okazaki National Research Institute |
|---|
Principal Investigator |
YAMASHITA Toshiro Okazaki National Inst., Inst.for Molecular Science, Associate Professor, 分子科学研究所, 助教授 (90116872)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TANAKA Shoji Okazaki National Inst., Inst.for Molecular Science, Research Associate, 分子科学研究所, 助手 (20192635)
|
|---|
| Project Period (FY) |
1995 – 1996
|
| Keywords | Organic Conductor / Organic Semiconductor / Single-Component Conductor / Conducting Polymer / Thiophene Oligomer / Electron Donor |
|---|
| Research Abstract |
Compounds containing both electron donor and acceptor units are expected to have small HOMO-LUMO gaps which lead to interesting properties such as intrinsic conductivity and nonlinear optical properties. They are also interesting as components for organic conductors because they are highly polarized and unique molecular assemblies may be formed by strong intermolecular interactions. We prepared here novel donor-acceptor compounds containing 1,2,5-thiadiazole units.
Benzobis (thiadiazole) with a nonclassical thiadiazole ring has a high electron affinity. Introduction of electron-donating groups afforded a new type of donor-acceptor compounds. Their cyclic voltammograms showed that they are easily both oxidized and reduced. Some of them have the absorption maxima above 700 nm due to the small HOMO-LUMO separation. X-ray structure analysis of the diphenyl derivative revealed the formation of a tap-like network through short S---N contacts.
A series of novel monomers containing aromatic-donor and o-quinoid-acceptor units were also prepared. One compound showed the absorption maximum at 1345 nm. Electrochemical oxidation of the monomers afforded polymers showing small bandgaps. The electrochemical bandgap of one polymer was found to be nearly zero. We have furthermore developed a new synthetic approach to precisely-defined conjugated oligomers containing various types of thiophene units. For example, a sexithiophene derivative showing an absorption maximum at 1097 nm was prepared.
|
