Effect of conjugation on the optoelectronic properties of pyrazine-based push-pull chromophores: Aggregation-induced emission, solvatochromism, and acidochromism

Abstract

A series of pyrazine-based bipodal D-π-A-π-D and D-π-A-π-A molecules with multi-stimuli response have been synthesized via Suzuki and Sonogashira cross-coupling reactions. We present a joint theoretical and experimental study to elucidate structure-property relationship of these push-pull chromophores. The modification of the end-capped donor-acceptor units and the extension of π-conjugation are key factors in tuning their optical, thermal and electrochemical properties. Depending on the different electron-donating substituents, the chromophores emit blue to orange fluorescence. The solvent dependent emission was observed and their Dimroth-Reichardt plots show a linear correlation. The aggregation-induced study shows enhanced emission in aggregates. Our work has elucidated that these small structural isomers can be utilized to develop a promising multi-stimuli responsive fluorescent materials.