Investigating stimuli-responsive luminescence and aggregation-induced emission properties of o-carborane-based luminophores modified with phenanthrene or anthracene

Abstract

Stimuli-responsive luminescence plays a crucial role in the development of mechanoluminescent materials. Here, we designed and synthesized four o-carborane-based aggregation-induced emission molecules, two of which, CB-Ph-P and CB-Ph-PAn, exhibited multiple solid-state fluorescence emissions. Upon mechanical stimulation, the recrystallization solid of CB-Ph-P caused a bathochromic shift in its fluorescence emission from 423 nm to 608 nm. Similarly, CB-Ph-PAn exhibits a transition in the fluorescence emission wavelength from 393 nm to 623 nm when in the solid state. In order to gain insight into the mechanism behind their luminescence behavior, we performed analyses including powder X-ray diffraction, photophysical properties, thermal properties, and single-crystal structure analysis. It is deemed that the polymorphism may be related to different weak interactions, packing modes and torsion angles.