Flexible π-Conjugated 2,5-Diarylamino-Terephthalates: A New Class of Mechanochromic Luminophores with Tunable Aggregation States.

The generation of different thermodynamically (meta)stable states is crucial for the development of smart solid-state luminescent materials. However, the design of luminophores with tunable aggregation states is remaining a grand challenge. Herein, we present a family of mechanochromic luminophores with tunable metastable states, based on the dynamically controllable π-π stacking of the flexible π-conjugated structure of 2,5-diarylamino-terephthalates in the solid state. The experimental data revealed that both the kinetically controlled metastable state and thermodynamic controlled stable state can be generated via tuning the intermolecular interactions such as π-π stacking and hydrogen bonds. As a result, the highly sensitive mechano-stimuli response of these luminophores was successfully achieved.