CuOx/OMS-2 catalyzed synthesis of 4,5-dicyano-1H-imidazoles moiety: Directly access to d-A system for AIE-active mechanofluorochromic materials

Abstract

• Efficient methodology for the synthesis of 4,5-dicyano-1H-imidazoles moiety. • TPE-DCI shown a AIE and MFC behavior. • TPE-DCI was successfully applied in cell staining. Although a lot of mechanofluorochromic (MFC) materials have been reported, it still needs to be further explored due to the lack of the universal design principle. The AIE moiety molecules with d -A framework have been widely regarded as the ideal structural models for MFC materials, because their optical properties is simply tuned by changing the molecule packing mode or conformation. Herein, we have developed a new and efficient synthetic methodology for the synthesis of 4,5-dicyano-1H-imidazoles moiety by using CuO x /OMS-2 as catalyst with excellent yields. The DCI moiety is a potential candidate for electron acceptor units and constructing the fluorescence skeleton with donor-acceptor system. Through the above synthesis method, we have constructed the new compound TPE-DCI with donor-acceptor framework by using tetraphenylethene as electron donor and DCI moiety as electron acceptor. As expected, TPE-DCI shown the excellent AIE behavior and significant MFC behavior (Δλ=25 nm). Furthermore, TPE-DCI was also successfully applied in cell staining. The results suggested that TPE-DCI is a promising candidate material for mechanical sensor, security protection and cell imaging.