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[摘要]:Azobenzene (AB) undergoes (E) -> (Z) isomerization upon exposure to light. Whereas the light-induced structural change can be exploited for numerous applications, a second, light-orthogonal switch would facilitate the development of new uses for AB derivatives. Electron-donating groups on the AB ring system change not only the absorption wavelengths, but also the isomerization properties. Experimental observations and computational studies suggest that the inclusion of multiple electron-donating groups can short-circuit the concerted inversion isomerization mechanism of AB by providing new conical intersections between excited states. This phenomenon has been exploited in a unique AB derivative where the conversion of a phenol into an ester restores the isomerization activity. |
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