Construction of a Layered Hydrogen-Bonded Organic Framework Showing High-Contrast Mechanoresponsive Luminescence Turn-On

This paper probes the mechanoresponsive luminescence and aggregation-induced emission (AIE) properties of N-phenylcarbazole-based thiophene/dicyanovinyl (T–DCV) derivatives. In bis-T–DCV planar molecule 1, a layered hydrogen-bonded organic framework (HOF) structure is formed with the assistance of multiple C–H···N and strong interlayer interactions. The formation of such a layer packing HOF structure can quench the solid fluorescent emission when aggregated as nanosuspensions but guarantees the high-contrast luminescence on–off switching (1.2 × 10³ fold) in the solid state. Moreover, the grinding-induced destruction of HOF 1 is reflected by powder X-ray diffraction measurements, in which the destruction of the α and β rings in the planar HOF stripe and the close interlayer stacking could be observed. This work achieves the successful construction of long-wavelength emission AIE molecules (2 and 3) by introducing sufficient steric hindrance rotors to disturb the intermolecular π–π stacking and/or dipole–dipole interactions.