Mechanical force-induced luminescence enhancement and chromism of AIE-active anthracene chalcone derivative

Abstract

It is highly desirable and significant to integrate the remarkable properties of mechanical force-induced luminescence enhancement and aggregation-induced emission (AIE) within a single simple molecule. In this study, a new novel AIE-active anthracene-based chalcone derivative APBP ((E)-1-(4-(anthracen-9-yl)phenyl)-3-(4-bromophenyl)prop-2-en-1-one) was designed and synthesized, and its photophysical properties, aggregation-induced emission behavior, and mechanical force-induced luminescence properties were systematically investigated. It is worth noting that, due to its high sensitivity to mechanical force, APBP exhibited reversible high-contrast turn-on mechanofluorochromism in response to mechanical force, accompanied by a substantial increase in the solid fluorescence quantum yield (QY), from 0.4% (pristine) to 36.8% (upon grinding). Additionally, a large red-shift of 46 nm from 488 nm to 534 nm was observed upon grinding. In other words, the prominent enhanced and larger red-shifted emission endows it with the characteristics of a high-contrast mechanofluorochromism material. The reversible phase transition between the well-ordered crystalline and amorphous states was responsible for the mechanical force-induced luminescence enhanced and chromism properties, as evidenced by powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), and differential calorimetric scanning (DSC) results. Furthermore, X-ray single-crystal diffraction results revealed that the observed fluorescence enhancement behavior was attributable to the disruption of both the π-π stacking and the H-Br interactions.