AIE-active non-planar phenothiazine-based derivatives with mechanical-induced emission enhancement characteristics

Abstract

Two new mechanofluorochromic-active AIE non-planar phenothiazine-based dyes (E)-N′-((10-ethyl-10H-phenothiazin-3-yl)methylene)-4-methylbenzenesulfonohydrazide (EPMMBS) and (E)-N′-((10-ethyl-10H-phenothiazin-3-yl)methylene)benzenesulfonohydrazide (EPMBS), were designed and successfully fabricated using a simple one step aldimine condensation reaction strategy. The synthesized compounds EPMBS and EPMMBS with subtly different electron-withdrawing moieties, have distinct mechanofluorochromic phenomenon via fluorescence color and emission intensity changes upon mechanical grinding. The mechanofluorochromism was supported by PXRD (powder X-ray diffraction) and FESEM (field emission scanning electron microscopy) which highlighted the phase transition between the well-organized crystalline and the amorphous phase. Our work could provide a promising way to design more mechanofluorochromic materials.