Thermally Irreversible Photochromic Systems. Reversible Photocyclization of 1,2-Bis(benzothiophen-3-yl)ethene Derivatives

Article abstract of DOI:10.1246/bcsj.63.1311

1,2-Bis(benzothiophen-3-yl)ethene derivatives, which possess thermally irreversible and fatique resistant photochromic properties, were synthsized. cis-1,2-Dicyano-1,2-bis(2-methylbenzothiophen-3yl)ethene Ia and 2,3-bis(2-methylbenzothiophen-3-yl)maleic anhydride 2a underwent reversible photocyclization to produce red-colored closed-ring forms with λ_max at 507 and 544 nm, respectively.The closed-ring forms were stable for more than 3 weeks at 80 deg C.The coloration/decoloration (ring closure/opening)cycles were able to be repeated more than 1E4 times with keeping the adequate photochromic performance.