(615e) Novel Synthesis Route for Symmetric and Asymmetric Diarylethene Molecules By Modifying Pendant Groups

Diarylethene(DTE) molecules have two forms, open form and close form, which have different properties in many aspects, such as absorption spectrum, refractive index, permittivity and chemical properties. The two forms can switch when irritating by UV radiation and visible light. DTEs are one of the key materials for volume holographic storage. But the synthesis process for DTEs are always too complicated for practical applications.  A new route for synthesizing symmetric and asymmetric diarylethene molecules bearing different functional groups was introduced. Treated by AlCl₃, 2-chloro -5- methyl thiophene converted to 1,5-bis(5-chloro-2-methylthiophen-3-yl)pentane-1,5-dione. After cyclization and reduction, (1,2-bis(5-chloro-2-methylthiophen-3-yl)cyclopent-1-ene, BCM-DTE) was obtained. DTEs with different pendant groups were obtained by Suzuki reaction using different boric acids. And symmetric and asymmetric DTEs can be synthesized at the same time. The whole process takes only 3 steps which are all simple and easily controlled. Massive DTEs can be produced by this method in commercial use. Also these DTEs have typical photochromic properties and could have promising applications in volume holographic storage.