2007 Fiscal Year Final Research Report Summary
Preparation of Novel Photon-mode Molecular switch based on Photcchromic Terarylene Derivatives
| Project/Area Number |
17350069
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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 |
Functional materials chemistry
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| Research Institution | Nara Institute of Science and Technology |
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Principal Investigator |
KAWAI Tsuyoshi Nara Institute of Science and Technology, Graduate School of Materials Science, Professor (40221197)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Yasuchika Nara Institute of Science and Technology, Graduate School of Materials Science, Associate Professor (80324797)
NAKASHIMA Takuya Nara Institute of Science and Technology, Graduate School of Materials Science, Assistant Professor (70379543)
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| Project Period (FY) |
2005 – 2007
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| Keywords | photochromic / photochromism / coniugated Polymer / single crystal / conducting polymer / molecular switch |
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| Research Abstract |
The properties of pi-conjugated polymers are strongly dependent on the extent of pi-conjugation expansion. The precise control of the expanse of pi-conjugation systems by means of external stimuli including light would give a guiding principle for future photo-switching molecular devices and molecular memories. In particular, photochromic molecules modulating pi-conjugation system reversibly upon light inadiation are expected as a promising material for such photo-switching modules. In this study, we have developed photo-switching molecules based on terarylenes that could control the pi-conjugation connection pathways upon reversible photochromic reactions. Terarylenes based on 4,5-diarylthiazole and 4,5-diarylimidazole(imidazolium) were synthesized. The 4,5-diarylthiazole terarylenes exhibited high photochromic performance including high photocyclization quantum yields and reactivity in single crystalline phase, which is attributed to the steric effect of central thiazole unit such as the reduced steric hindrance and the stabilization of photo-reactive conformation with intramolecular hydrogen-bonding. The thermal stability of ring-closed colored isomer of terarylenes could be dramatically modulated by controlling the aromaticity of arylene components. Interestingly, a terarylene based on 4,5-dithienyl thiazole having four phenylethynyl units at thienyl groups showed the bleaching lifetime as short as 5 sec at room temperature.
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