Stimuli‐Responsive Properties on a Bisbenzofuropyrazine Core: Mechanochromism and Concentration‐Controlled Vapochromism

Stimulus-responsive organic materials with luminescence switching properties have attracted considerable attention for their practical applications in sensing, security, and display devices. In this paper, bent-type bisbenzofuropyrazine derivatives, Bent-H and Bent-sBu, with good solubilities were synthesized, and their physical and optical properties were investigated in detail. Bent-H gave three crystalline polymorphs, and they showed different luminescence properties depending on their crystal packing structures. In addition, Bent-H exhibited mechanochromic luminescence in spite of its rigid skeleton. Bent-sBu exhibited unique concentration-dependent vapochromic luminescence. Ground Bent-sBu was converted to blue-emissive, green-emissive, and green-emissive high-viscosity solution states at low, moderate, and high concentrations of CHCl3 vapor, respectively. This finding represents a concentration-dependent multi-phase transition with an organic solvent, which is of potent interest for application in sensing systems.This is the accepted version of the following article: Nakamura Shotaro, Okubo Kohei, Nishii Yuji, et al. Stimuli‐Responsive Properties on a Bisbenzofuropyrazine Core: Mechanochromism and Concentration‐Controlled Vapochromism. Chemistry – A European Journal, e202302605 (2023), which has been published in final form at https://doi.org/10.1002/chem.202302605. This article may be used for non-commercialpurposes in accordance with the Wiley Self-ArchivingPolicy [https://authorservices.wiley.com/author-resources/Journal-Authors/licensing/self-archiving.html