| 摘要 |
PURPOSE:To obtain a benzofuran compound having photochromic properties and being stable in each isomeric form by reducing a specified benzofuran compound. CONSTITUTION:A benzofuran compound of formula I, wherein R1 to R10 may be the same or different and are each a group having at least one carbon atom, H or X (wherein X is F, Cl, Br or I). This compound for example 3,3'-azobis(2- methylbenzofuran) can be obtained by treating 2-methyl-3-nitrobenzofuran with ethanol, a sodium hydroxide solution and a zinc powder. The benzofuran compound in the form of an isomer of formula I is converted into an isomer of a structure of formula II by irradiation with light of a specified wavelength (lambda1). The isomer of formula II is reconverted into the initial isomer by irradiation with light of a specified wavelength (lambda2). During this conversion, the compound does not undergo any change in molecular weight but undergoes a change in structure to change its adsorption wavelength. |
