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.

本研究探讨了基于N-苯基咔唑的噻吩/二氰乙烯基（T–DCV）衍生物的机械响应发光与聚集诱导发光（AIE）性能。在双T–DCV平面分子1中，借助多重C–H···N氢键与较强的层间相互作用，形成了层状氢键有机框架（HOF）结构。该层状堆积的HOF结构在形成纳米悬浮聚集体时会淬灭固态荧光发射，但在固态下可实现1.2×10³倍的高对比度发光开关行为。此外，通过粉末X射线衍射测试可观测到研磨诱导的HOF 1结构破坏：平面HOF条带中的α与β环结构以及紧密层间堆叠均被破坏。本工作通过引入具有足够空间位阻的转子，以干扰分子间π-π堆积和/或偶极-偶极相互作用，成功构建了长波长发射的AIE分子（2和3）。