Reversible photochromic tetraphenylethene-based Schiff base: Design, synthesis, crystal structure and applications as visible light driven rewritable paper and UV sensor

Abstract

Abstract “Paper” plays an important role in the development and spread of civilization. However, massive use of paper has led to nonnegligible negative influence on environment. Recently, great progresses have been made in the fields of rewritable paper that has enormous potential in alleviating the increasing demand for paper. Therefore, we report a new photochromic tetraphenylethene-based Schiff base derivative 2-ethoxy-6-(((4-(1,2,2-triphenylvinyl)phenyl)imino)-methyl)phenol (TPENOEt). TPENOEt exhibits reversible photochromic behavior, fast response, simple synthetic step, lower cost and excellent fatigue resistance. The bleaching rate of TPENOEt is tunable by longer wavelength light, white light irradiation and elevated temperature. The fluorescence of TPENOEt is weak in solid state, which increases obviously after grinding with a pestle accompanied by reduced photochromic efficiency and longer response time. These results provide a new view to get insight into the relationship between packing style and fluorescence/photochromism property of Schiff base derivatives. TPENOEt is successfully applied as a visible light driven rewritable paper, 410\u202fnm violet light can serve as a pen, while 420–590\u202fnm visible light and white light is employed as the eraser. The recorded information will be erased in about 15\u202fs after white light irradiation and will be self-erased in 20\u202fmin in daylight and in about 15 days in dark. Moreover, TPENOEt can also serve as a UV strength sensor for naked eye detection of UV radiation pollution.