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.