| Budget Amount *help |
¥3,180,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥180,000)
Fiscal Year 2007: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2006: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2005: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
On treatment with base, dioxetane bearing a hydroxyaryl group gives unstable dioxetane bearing an oxidophenyl group, which rapidly decomposes with the accompanying of bright light emission. On the other hand, thermal decomposition of rather simple dioxetane gives triplet-excited carbonyl so that effective chemiluminescence is hardly expected. In this work, we attempted to realize crystalline dioxetanes with high melting point and to investigate whether or not they cause decomposition accompanied by light emission without any addition of base in a solid state. Thus, we designed and synthesized a variety of bicyclic dioxetanes bearing a benzothiazol-2-yl, benzoxazol-2-yl, or benzimidazol-2-yl group, which were obtained as crystals with high melting point.
All these dioxetanes underwent base-induced chemiluminescent decomposition with high efficiency not only in an aprotic polar solvent but in an aqueous medium. Furthermore, we found that bicyclic dioxetanes bearing a benzothiazol-2-yl group underwent unprecedented decomposition promoted by aprotic polar solvent (SPD) without any base to give bright light with efficiency as high as that for base-induced decomposition BID). This SPD was clarified to be entropy-controlled reaction differently from the BID. On the other hand, thermal decomposition of benzothiazol-substituted dioxetanes in a nonpolar solvent such as toluene gave light due to excited state intramolecular proton transfer (ESIPT).
5-Adamantanyl-1-(3-hydroxyphenyl)-4, 4-dimethyl-2, 6, 7-trioxabicyclo [3. 2. 0] heptane was synthesized also as a dioxetane with high melting point. This dioxetane did not give observable light in a solid state on simple heating. However, this dioxetane was found to undergo base-induced decomposition to give bright blue light in a crystalline state. This topochemiluminescence was observed for a simple mixture of the crystalline dioxetane and crystalline DMAP as well as for cocrystals of this combination.
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