Research Abstract |
Dioxetanes having an electron-donor decompose to emit light effectively by the CIEEL (chemically initiated electron exchange luminescence) mechanism. Thus, the CIEEL-active dioxetanes would be a promising entry to a variety of chemiluminescent substrates. In this work, we investigated design and synthesis of new CIEEL-active dioxetanes emitting a long-wavelength light (crimson light). 1) 5-t-Butyl-1-[(t-butyldimethylsiloxy)benzothiazol-2-yl]-4, 4-dimethyl-2, 6, 7-trioxabicyclo[3. 3. 0]-heptane emitted crimson light (maximum wavelength = 730nm). 2) Dioxetanes substituted with 3-oxyphenyl bearing an aryl substituent at the 4- or 5-position emitted light with maximum wavelength longer than that for 3-oxyphenyl-substituted dioxetane. Among these dioxetanes, 4-azolylphenyl-substituted dioxetanes emitted light effectively also in aqueous media. 3) New CIEEL-active dioxetanes, 5-aryl-1-t-butyl-4, 4-dimethyl-2, 6, 7-trioxabicyclo[3. 2. 0] heptanes, which afford an aromatic ketone as an emitter, were synthesized and found to emitt light with maximum wavelength longer than the corresponding 5-aryl-1-t-butyl isomers. 4) A3-(cyanomethyl)phenyl-substituted dioxetane emitted crimson light (maximum wavelength = 702nm). This new type dioxetane decomposed through an intermediary dioxetane bearing a benzylic carbanion.
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