Fluorene-based gold(I)-containing AIEgens with substituents exhibiting diverse electronic effects: hypsochromic mechanofluorochromism, force-induced substantial weakening of fluorescence intensity and its anti-counterfeiting application

Due to their distinctive stimulus-responsive properties, materials exhibiting hypsochromic mechanofluorochromism (MFC) or force-induced substantial weakening of fluorescence intensity have demonstrated remarkable application potential in the field of information security. This study designed and synthesized two novel fluorene-based dinuclear gold(I) complexes, 1 and 2 . Both molecules exhibited aggregation-induced emission (AIE) characteristics. Specifically, complex 1 showed reversible hypsochromic MFC. In contrast, complex 2 exhibited force-induced substantial weakening of fluorescence intensity. It is worth noting that 2 is the first example of gold(I)-based luminogen capable of simultaneously exhibiting AIE and force-induced substantial weakening of fluorescence intensity. Based on the force-induced significant fluorescence attenuation feature of luminogenic complex 2 , an interesting information anticounterfeiting system involving a pizza model was successfully established. This work not only reports the first example of AIE-active gold(I) complex featuring anisotropic mechanical force-induced pronounced fluorescence reduction but also provides a valuable reference for anticounterfeit applications of mechanically responsive luminogens.