Mechanoluminescence or Room-Temperature Phosphorescence: Molecular Packing-Dependent Emission Response

Mechanoluminescence (ML) and room-temperature photophosphorescence (RTP) were achieved in polymorphisms of a triphenylamine derivative with ortho-substitution. This molecular packing-dependent emission afforded crucial information to deeply understand the intrinsic mechanism of different emission forms and the possible packing-function relationship. With the incorporation of solid-state ¹³ C NMR spectra of single crystals, as well as the analysis of crystal structures, the preferred packing modes for ML and/or RTP were investigated in detail, which can guide the reasonable design of organic molecules with special light-emission properties.

A Three-Dimensional Dynamic Supramolecular "Sticky Fingers" Organic Framework

Engineering high-recognition host-guest materials is a burgeoning area in basic and applied research. The challenge of exploring novel porous materials with advanced functionalities prompted us to develop dynamic crystalline structures promoted by soft interactions. The first example of a pure molecular dynamic crystalline framework is demonstrated, which is held together by means of weak "sticky fingers" van der Waals interactions. The presented organic-fullerene-based material exhibits a non-porous dynamic crystalline structure capable of undergoing single-crystal-to-single-crystal reactions. Exposure to hydrazine vapors induces structural and chemical changes that manifest as toposelective hydrogenation of alternating rings on the surface of the [60]fullerene. Control experiments confirm that the same reaction does not occur when performed in solution. Easy-to-detect changes in the macroscopic properties of the sample suggest utility as molecular sensors or energy-storage materials.