Manipulating Light‐Induced Dynamic Macro‐Movement and Static Photonic Properties within 1D Isostructural Hydrogen‐Bonded Molecular Cocrystals

Abstract

Smart molecular crystals with light‐driven mechanical responses have received interest owing to their potential uses in molecular machines, artificial muscles, and biomimetics. However, challenges remain in control over both the dynamic photo‐mechanical behaviors and static photonic properties of molecular crystals based on the same molecule. Herein, we show the construction of isostructural co‐crystals allows their light‐induced cracking and jumping behaviors (photosalient effect) to be controlled. Hydrogen‐bonded co‐crystals from 4‐(1‐naphthylvinyl)pyridine (NVP) with co‐formers (tetrafluoro‐4‐hydroxybenzoic acid (THA) and tetrafluorobenzoic acid (TA)) crystallize as isostructural crystals, but have different static and dynamic photo‐mechanical behaviors. These differences are due to alternations in the orientation of NVP and hydrogen‐bonding modes of the co‐formers. After light activation, the 1D NVP‐TA crystal splits and shears off within 1 s. For NVP‐THA, its photostability and high quantum yield give novel photonic properties, including low optical waveguide loss, highly polarized anisotropy, and efficient up‐conversion fluorescence.

Programmable photoresponsive materials based on a single molecule via distinct topochemical reactions

“…18,22 On the one hand, the spatial movements of lattice atoms will generate local stress in surrounding p-dimers, enabling the deformation of crystals. 23,24 For instance, Naumov and Vittal reported smart molecular crystals based on [2 + 2] photocycloaddition, achieving a variety of photomechanical dynamic behaviors such as bending, jumping, rolling, and photosalience. [25][26][27] On the other hand, special uorescence changes can be observed in photodimerization due to the breakage of the initial p-dimer structure.…”

Stacking-dependent tetracolour luminescence and mechanofluorochromic properties of an isoquinoline derivative with aggregation-induced emission

“…Organic molecules with solid-state fluorescence have drawn great attention in the past two decades because of their wide applications in the field of anti-counterfeiting materials, optical sensors, and organic light-emitting devices. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] The solid-state emission of an organic molecule is directly associated with its morphology, which is strongly influenced by the molecular conformation, intermolecular interaction, and stacking mode. [15][16][17][18] According to the reports in the literature, 19,20 nearly one-third of organic compounds can adopt more than one crystalline structure and some of them might have polymorphs emitting fluorescence with different colours.…”

Crystal Engineering-Driven Sunlight Responsiveness and Flexible Waveguide Transmission

“…Driven by various mechanisms such as [2+2] cycloaddition, [4+4] cycloaddition, cis–trans isomerization, electrocyclization, and tautomerization, molecular crystals exhibit diverse properties, including bending, jumping, curling, fracturing, and twisting, − showcasing immense potential in fields like artificial muscles, micromechanics, light switches, actuators, and oscillators. − However, the currently reported light-driven actuators typically require artificial light sources [e.g., lasers, light-emitting diodes (LEDs), or xenon lamps] and manual control of the light direction to achieve crystal deformation, increasing the complexity of the driving system and limiting material miniaturization and intelligence. In contrast, the importance of sunlight, with its advantages of contactless operation, simple control, safety, and infinite resources, is undeniable.…”