Dynamic Timing Control over Multicolor Molecular Emission by Temporal Chemical Locking

Abstract

Dynamic control over molecular emission, especially in a time‐dependent manner, holds great promise for the development of smart luminescent materials. Here we report a series of dynamic multicolor fluorescent systems based on the time‐encoded locking and unlocking of individual vibrational emissive units. The intramolecular cyclization reaction driven by adding chemical fuel acts as a chemical lock to decrease the conformational freedom of the emissive units, thus varying the fluorescence wavelength, while the resulting chemically locked state can be automatically unlocked by the hydrolysis reaction with water molecules. The dynamic molecular system can be driven by adding chemical fuels for multiple times. The emission wavelength and lifetime of the locking states can be readily controlled by elaborating the molecular structures, indicating this strategy as a robust and versatile way to modulate multi‐color molecular emission in a time‐encoded manner.

Bioinspired Self-Resettable Hydrogel Actuators Powered by a Chemical Fuel

“…Thus far, significant efforts have been made to develop nonequilibrium smart hydrogels controlled by synthetic CRNs. − A pioneering example is active hydrogels controlled by the exceptional Belousov–Zhabotinsky reaction, resulting in oscillating actuation of the hydrogels. , Nonetheless, the Belousov–Zhabotinsky reaction often suffers from the problems of poor control and fairly difficult design, stagnating the further advancement of hydrogels. In recent years, scientists have coupled chemical fuel-regulated nonequilibrium CRNs to molecular self-assembly − and dynamic cross-linking of hydrophilic polymers, − giving rise to various active hydrogel materials that show fuel-controlled autonomous hydrogelation behaviors. Very recently, Walther’s and Matsusaki’s groups have further extended this concept to enable transient volume-phase transitions of hydrogels, adding a step to the development of autonomous hydrogel actuators, although these systems suffer from serious deteriorations caused by the accumulation of wastes or slow response speed (days).…”

Tunable Nano‐Bending Structures of Loosened/Tightened Lassos with Bi‐Stable Vibration‐Induced Emissions for Multi‐Manipulations of White‐Light Emissions and Sensor Applications

“…As per previous reports, the PL emission colors of VIE-fluorophoric DPAC can be affected by the variations of different bending angles due to their dissimilar degrees of constraints. [51][52][53][54] In case of mechanically interlocked molecular architectures of [1]rotaxanes before and after shuttling under reversible acid/base stimuli, the changes in the interlocked structures may alter its conformational freedom in DPAC and thereby affect the photophysical properties of [1]rotaxanes. According to the corresponding molecular structures of tightened lasso [1]RB, loosened lasso [1]RA, and non-interlocked M-Boc in THF, distinct emission colors of cyan (𝜆 em = 480 nm), white (𝜆 em = 480 and 600 nm), and orange (𝜆 em = 600 nm) PL emissions could be observed in Figure 2a.…”

“…[50] The DPAC moiety reveals intrinsic blue-and orange-emission colors according to its respective bent and planar excited states, which can be controlled by several strategies, such as noncovalent cyclization, covalent chemical locking, micro-environmental confinement, molecular switching, and polymer surrounding matrix. [51][52][53][54][55][56][57][58][59][60] The uniqueness and versatility of DPAC moiety suggest potential applications for the construction of tunable light-emitting materials.…”

Facile construction of AIE-active pyridinyl-diphenylacrylonitrile derivatives with optical properties finely modulated by D–A regulation

“…Organic fluorescent materials have broad application prospects in the fields of optoelectronic devices, fluorescence sensing, biological imaging, high-efficiency lighting, and disease diagnosis and treatment. [1][2][3][4][5][6][7] In the field of organic light-emitting materials research, exploring novel systems with simple structures and high performance has remained in focus. [8][9][10][11][12][13] Luminogens with AIE features (AIEgens) have attracted extensive attention in the past two decades, owing to their superior photophysical properties compared to the traditional luminescent systems, which exhibit the aggregation-caused quenching (ACQ) effect.…”