Aggregation‐Induced Enhanced Emission of a Dimethylacridan Substituted Pyrimidine Derivative

Abstract

A pyrimidine chromophore bearing an acridan fragment was synthesized and its photophysical properties were studied. In solution, this compound is characterized by an important positive emission solvatochromism with a shift of 5800 cm−1 between nonpolar heptane and dichloromethane (DCM) associated with large Stokes shifts (up to 9100 cm−1 in DCM). Mono‐exponential fluorescence decays are observed in heptane whereas more complicated bi‐ or three‐exponential decays are observed in more polar solvents due to an interplay between locally excited and charge transfer excited state. Additionally, an aggregation‐induced enhanced emission process was demonstrated in THF/water mixtures. At low temperature (77 K), in a polymethylmethacrylate (PMMA) thin film, the presence of an accessible triplet state (T1) was demonstrated, which was not observed in solution. Finally, we show that it is possible to protonate the chromophore in thin film leading to panchromatic dual emission

Photophysical and redox properties of new donor–acceptor–donor (DAD) compounds containing benzothiadiazole (A) and dimethyldihydroacridine (D) units: a combined experimental and theoretical study

“…Similar solvatochromic effects were observed for other acridan derivatives due to the twisted nature of these molecules. 42 Independent of the solvent, the character of the emission indicated a CT-type luminescence.…”

“…This is a common phenomenon in the case of DA and DAD compounds tested in solvents of increasing polarity, including previously studied acridan derivatives. 42–45 The incorporation of two methyl groups in the 1,4-phenylene linker of 2 caused a 7-fold decrease of its PLQY as compared to the PLQY of 1 . This decrease can be related to the steric hindrance between the donor and the acceptor units.…”

Luminogenic and Bactericidal Studies of an Acrylonitrile‐Based AIEgen

“…Aggregation is a common occurrence observed in most molecular systems with π‐π stacking and frequently results in aggregation‐caused quenching (ACQ). Despite the likelihood of quenching of emission owing to π‐π stacking, certain molecules exhibit aggregation‐induced emission (AIE) in the solid state as a result of slipping molecular arrangements [10–12] . Devising an AIE system is important and interesting.…”