Dimethylamine substituted bisbenzocoumarin amides with solvatochromic and mechanochromic properties

Abstract

Stimuli responsive luminescent materials have attracted increasing attention for their potential application in many fields. In this work, dimethylamine substituted bisbenzocoumarins amides (DBCE and DBCP) are synthesized and their optical properties are investigated. These molecules show solvatochromic properties. The orange fluorescence emission of DBCE in crystalline state is blue-shifted to yellow emission upon grinding. The orange color could be recovered by recrystallization process. Powder wide-angle X-ray diffraction and DSC experiments reveal that the transformation from crystalline states to amorphous states under external stimuli is responsible for the mechanochromic properties. This work developed a new kind of binaphthane-type luminescent materials with blue-shifted mechanochromic properties.