Synthesis and Property of Dichroic Photochromism of Bipyridinium Bis(phosphonate)s
| Project/Area Number |
12650696
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | University of Yamanashi |
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Principal Investigator |
NANASAWA Masato University of Yamanashi, Faculty of Engineering, Professor, 工学部, 教授 (70020451)
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| Co-Investigator(Kenkyū-buntansha) |
KUWABARA Tetsuo University of Yamanashi, Faculty of Engineering, Research Associate, 工学部, 助手 (70273034)
HIRAI Michiko University of Yamanashi, Faculty of Engineering, Research Associate, 工学部, 助手 (00303397)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2002: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 2001: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 2000: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Viologene / Photo-reductive coloration / Photochromism / Dichroism / Alkanephosphonic acid / 光還元 / サーモクロミズム |
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| Research Abstract |
The viologens, bis-quaternary salts of 4,4'-bipyridine turn to intensive blue radical cations by one-electron by photochemical reaction. With the intention to evaluate the reversible photo-reduction(photochromism), the synthesis and dichroism of viologens with alkanephophonate anions which possess relatively good nucleophilicity and anisotrophic character was investigated. N,N'-dialkyl-4,4'-bipyridinium dihalides were prepared by two steps of Menshutkin reactions with different alkyl halides and their counter ions were exchanged with alkanephosphonates using an anion-exchange resin. ^1H-NMR and elemental analyses indicated that the viologens consist of two phosphonate anions, and protons at pyridinium rings are shifted to higher field, presumably due to low electrostatic interaction with bulky bivalent phophonate anions. This causes that the phosphonate salts are thermally unstable and decompose at relative low temperature without melting.
The radical formation by near-UV irradiation is small in organic solvents possessing high ionization potential. The photo-reduction in high-diluted solvents possessing electron-donating property (low IP) mainly proceeds by the ET-reaction from surrounding solvent molecules. The radical cations in glass sandwiched PVC-films were observed by steady state UV-irradiation, and the color of the radical cations persisted for several days. IR-spectra indicate that the photo-induced reduction of solid phosphonate salts proceeds from counter anion within a viologen molecule. When films were prepared by gradually cooling the melted viologen-bisphosphonate with alkanephosphonic acids, the absorption at 530 nm corresponds to the dimeric radical cation increased compared with rapidly cooling ones. While the absorption difference was small, the films of viologen-bisphosphonate salt showed dichroism by the orientation of viologen molecules in anisotropically organized alkanephosphonic acids.
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Report
(4 results)
Research Products
(12 results)
