Dual control of passive light output direction by light and mechanical forces in elastic crystals

Abstract

An organic crystal with photomechanical and elastic properties has been prepared.

Superelastic and Photomechanical Behavior of Acylhydrazone Derivative Crystals

“…As depicted in Scheme 1, TBMP was synthesized by refluxing picolinohydrazide and 4′-(trifluoromethyl)-[1,1′-biphenyl]-4-carbaldehyde in ethanol, achieving a yield of 70%. 54 The compound exhibited absorption peaks at 262 nm (highest occupied molecular orbital (HOMO) → lowest occupied molecular orbital (LUMO) + 1) and 321 nm (HOMO → LUMO) in acetonitrile solution, indicating the π−π* transition of the molecule (Figure 1, Tables S1 and S2). In addition, the molecules in the microcrystals showed significant π−π accumulation, shifting the maximum absorption peak to 370 nm (Figure S1).…”

“…Conversely, although the crystal (001) plane also exhibits hydrogen bond interactions, the corresponding maximum intermolecular energy is −75.1 kJ/mol, making it unable to accommodate crystal deformation and leading to fracture (Figures and S6). In our previous study, we introduced the CF 3 -free compound ( E )- N ′-([1,1′-biphenyl]-4-ylmethylene)­picolinohydrazide ( BPMP ) . When pressure was applied along the (100) direction, the crystal fractured (Figure S7a).…”

“…In our previous study, we introduced the CF 3 -free compound (E)-N′-([1,1′-biphenyl]-4-ylmethylene)picolinohydrazide (BPMP). 54 When pressure was applied along the (100) direction, the crystal fractured (Figure S7a). Analysis of the single-crystal data revealed a substantial presence of C−H•••π interactions between the upper and lower molecules (Figure S7b).…”

“…Hao’s group reported a plastically flexible α-cyanostilbene crystal with excellent photomechanical bending properties . Meanwhile, other photomechanical movements of elastic crystals have been reported in recent years. − Based on these aforementioned studies, it is clear that the combination of flexibility and photomechanical properties in crystals is undeniably crucial for improving their survivability as photosensitive materials. Common flexible properties include elasticity, superelasticity, ferroelasticity, plasticity, and superplasticity .…”

The photomechanical bending and photosalient effect of flexible crystals of an acylhydrazone

“…Among the photoswitches that have been studied so far, acylhydrazones, in their crystalline state, are relatively less explored with respect to their photomechanical effects. We discovered the photomechanical bending and photosalient effect of the acylhydrazone derivative for the first time, 50 and so far a total of seven publications 50–56 reported on acylhydrazone single crystals displaying mechanical effects. In this manuscript, we are reporting another instance of the photomechanical bending followed by the PS effect displayed by the elastically flexible crystals of an acylhydrazone derivative viz.…”