Synthesis And Study On Multi-thiophene Photochromic Compounds

The research on diarylethene photochromic compounds is focused on the molecules containing only one photochromic unit recently, but the molecules containing two or more photochromic units are scarcely studied. Futhermore, thiophenes are ideal building blocks in transition metal-catalyzed cross-coupling reactions, and there are uncountable methods to modify the core molecule, and due to multi-thiophenes containing largeπconjugated system, they have good electron or energy transmission capacity. Therefore, in order to study the photochromic properties of the compounds containing two photochromic units, we designed and synthesized mutil-thiophenes which ethene bridges were thiophene and substituent groups of aryl ring were thiophenes via Suzuki coupling reaction, and the properties of these compounds were studied. We found that multi-thiophenes are fast response, but whether the two photochromic units are cyclized simultaneously is still in research.Trans-diarylethenes which ethene bridges were 1,2-dicyanoethene was demonstrated that they performed photochromism directly without any additional preprocesses, they are comparatively slow response. In view of this, we tried to synthesize some diarylethenes which substituent groups of aryl ring were electron-withdrawing groups. Compared with the compounds which were synthesized before, we found that these compounds were excellent photoactivity and fast response.Due to the specific structural features and the properties of dendrimer, we designed two multi-thiophene dendrimers which contain multi-switches, and explored the properties.