Asymmetric Dual‐State Emitters Featuring Thiazole Acceptors

This work describes a new approach to construct highly conjugated molecules with asymmetric donor‐acceptor‐donor’ architectures (D−A−D’). Five new emissive compounds featuring thiazole, a scarcely used acceptor, were synthesized using a three‐component Rh(II) catalytic reaction. The asymmetric fluorescent compounds show significant emission in solution (QY=73 %–100 %) and the solid‐state (QY=14 %–59 %), and therefore considered Dual‐State Emitters (DSE). We also evaluate the impact of O‐alkyl chains with varying lengths in the photophysical properties in solution, aggregates, and solid‐state. Computational studies indicate that the involved electronic transitions have a significant charge transfer character produced almost exclusively from the triphenylamine donors. According to the single crystal X‐ray data of compounds 8 and 9, the conjugated structures have a twisted molecular conformation that contributes to the observed emission in the solid‐state. These findings show a systematic approach to design DSE materials, which may help to stimulate their use in biological or optoelectronic applications. In this work, a new series of thiazole‐based dual‐state emission fluorophores with self‐isolation properties in solution and good emission in the solid state are reported.