Sectional intramolecular charge transfer manipulating in a D-A-D' coumarin derivative for recessive rewritable paper.

External-stimuli-responsive rewritable paper has attracted significant attention for application in secure information. However, to encrypt information on papers which can not be read out under visible light is still challenging. In this work, recessive rewritable paper for security information handling was realized via sectional intramolecular charge transfer (SICT) manipulating in a delicately designed coumarin derivative CMNT. By rational arranging a thiophenyl group and a diethylamino group as electron donors at the 3- and 7-position of coumarin skeleton, respectively, CMNT exhibited obvious fluorescence switching upon BF 3 and trimethylamine stimuli. After impregnating a filter paper into CMNT solution with low concentration (1 × 10−6 M), no color change of the paper could be observed under visible light. Meanwhile, when writing and erasing the information on the paper by BF 3 ink and trimethylamine eraser, respectively, the process can only be witnessed under UV light. Studies revealed the ICT effect from diethylamino group to chromen-2-one was suppressed after adding BF 3 , while the ICT channel from thiophenyl group to chromen-2-one was retained, thus producing such unique phenomenon. A recessive rewritable paper was developed based on a coumarin derivative with sectional intramolecular charge transfer manipulating. [Display omitted] • A D'-A-D coumarin derivative named CMNT , with simple structure based on the ICT effect was designed and synthesized. • CMNT can be a reversible BF 3 sensor and the sensing system was realized by sectional intramolecular charge transfer. • A recessive rewritable paper was fabricated by impregnating a filter paper into CMNT solution (1×10-6 M). • The writing by BF 3 ink is only readable on exposure to ultraviolet light, and is trimethylamine erasable for rewriting. [ABSTRACT FROM AUTHOR]