Alkyne-inserted tetraphenylethylene derivatives: enhanced aggregation-induced emission via intramolecular and intermolecular interactions

Abstract

Solid-state luminescence is often hindered by aggregation-caused quenching (ACQ), prompting the search for efficient aggregation-induced emission (AIE) materials. Tetraphenylethylene (TPE), a star molecule in AIE research, has been widely used to study the restricted intramolecular motion (RIM) mechanism through structural modifications. Breaking from traditional peripheral modification, we engineer the TPE core by inserting an alkynyl linker between the triphenylethylene (TriPE) core and planar chromophores (TriPE-yn-Ar), where the alkynyl bond length and spatial orientation dictate molecular conformations, intermolecular interactions, and crystal packing, as well as the torsional oscillation along the rotation axis. The TriPE-yn-9-Phen exhibits J-aggregation-enhanced emission, with quantum yields of 69.9% in the solid state and 88.4% in the crystal. This central modification strategy opens new avenues for designing advanced AIE materials.