2005 Fiscal Year Final Research Report Summary
Enantiospecific photochromic reaction of thiophenophan-1-enes
| Project/Area Number |
16550126
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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 |
Functional materials chemistry
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| Research Institution | Saga University |
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Principal Investigator |
TAKESHITA Michinori Saga University, Department of Chemistry and Applied Chemistry, Associate Professor, 理工学部, 助教授 (40274534)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Photochromism / Cylophane / Photomemory / Enantiomer / Non-destructive read-out / Optical resolution / Refractive index / Photoreversible |
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| Research Abstract |
Dithia-(dithienylethena)phane derivatives, composed of dithienylethene moieties and benzene bridges, were synthesized by a coupling reaction of the corresponding bis(chloromethyl)benzene with bis(mercaptomethyl)dithienylethene under high-dilution conditions. The products exhibit photochromic properties upon irradiation with ultraviolet and visible light. The photocyclization and cycloreversion quantum yields were determined, and a relationship between the photocyclization quantum yield and distance between the reactive carbon atoms of the phane derivatives established. The ortho isomer has a high efficiency in photocyclization due to its fixation in the photo-active anti conformation and short distance between the two reactive carbon atoms. The thermal stability of these photochromic compounds has been studied and the ortho isomer found to show thermal irreversibility.
Photochromic [2.2]metacyclophan-1-ene in a PMMA (polymethylmethacryate) film reversibly changed the refractive index, which was estimated by ellipsometric analysis. For example, the refractive indexes of the open form and the photostationary state at 352 nm in PMMA films (10.6%) were 1.4934 and 1.4996 at 901.82nm, respectively, and the variation (Δn) was 0.0062. The calculated refractive indexes of the open and closed forms were 1.744 and 1.859, respectively. The refractive index of the PMMA film containing a photochromic dye changed photoreversibly due the photochromic reaction between the open and closed forms of [2.2]metacyclophan-1-ene.
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