四苯乙烯 光致变色

A series of new diarylethene compounds with both photochromism and aggregation-induced emission have been synthesized by connecting tetraphenylethene and triphenylethene to …

… intrinsic photochromic behavior … photochromism with excellent fatigue resistance. Detailed spectroscopic, crystallographic, and computational investigations reveal that the photochromic …

In molecules with both AIE and photochromic properties, light exchange between absorption and fluorescence is reversible under alternating UV/visible treatment.

Abstract We designed and synthesized two new visible light triggered photochromic and aggregation-induced emission compound derived from the third generation donor−acceptor Stenhouse adducts (DASAs) with indoline-tri/tetra-phenylethylene moiety (abbreviation: SPE-IF/TPE-IF). The chemical structures of these compounds are identified by NMR, MS and so on. The key intermediate SPE-ID/TPE-ID as donor showed excellent AIE properties in water-THF (v/v) solutions. The absorption and emission of SPE-IF/TPE-IF were investigated by UV–Vis and fluorescence spectroscopy, respectively. The results shown they exhibited photochromic with fatigue resistance and fluorescent switching properties with visible light regulation. The open/colored triene and closed/colorless cyclopentenone isomers of SPE-IF/TPE-IF were equipped with high photo bleaching and fluorescence effect upon alternating visible light irradiation and heating both in solution and in PMMA doped solid state. And the solvent dependence effect of TPE-IF was studied. The photochromic mechanism of SPE-IF/TPE-IF was also basically investigated by computational method. These results indicate SPE-IF or TPE-IF is a promising candidate for visible light-responsive smart materials.

Tetraphenylethylene (TPE) derivatives are key building blocks for solid-state fluorophores, offering tunable emission wavelengths and high quantum efficiencies. While it is nowadays well established, especially in recent literature, that rotation...

Aggregation-induced emission (AIE) smart materials with multiple stimulus responses have a wide range of applications. Here, a series of tetraphenylethylene (TPE) derivatives, TPEN …

… complexes consisting of tetraphenylethylene and spiropyran. … (tetraphenylethylene) and the photochromic molecule (spiropyran). This coordination results in exceptional photochromic …

Stimuli-responsive chromic materials have sensitive responses to mechanical, thermal, chemical vapor, and light stimuli, which exhibited as mechanochromism, mechanoluminesence, thermochromism, vapochromism, photochromism and Ex-De luminescence, etc. Tetraphenylethene (TPE) scaffold as...

… include mechanochromic, photochromic, and excitation … Photochromic materials show reversible photoinduced … Thus, fast-responding, self-recovering, photochromic systems with simple …

… tetraphenylethylene. For example, the structure reversal and changes in the dihedral angle of the benzene ring may lead to changes in tetraphenylethylene … used a tetraphenylethylene …

Three imidazole-fused tetraarylethylene fluorescent probes (TPT-DPIo, TPT-PIo, and TPT-PHIo) featuring a unified molecular scaffold that integrates photochromism, multi-analyte …

… transfer (ESIPT) process derived from tetraphenylethylene and 4-(dodecyloxy)-2-… photochromism in original powder and crystalline states. In contrast, P5C12 exhibits photochromism …

… Detailed photochromic studies show that all three compounds display rapid … photochromic properties offers a new approach to developing advanced triarylethylene photochromic …

The rational design of stimuli-responsive materials requires a deep understanding of the structure-activity relationship. Herein, we proposed an intramolecular conformation-locking strategy─incorporating flexible tetraphenylethylene (TPE) luminogens into the rigid scaffold of a molecular cage─to produce a molecular photoswitch with dual outputs of luminescence and photochromism in solution and in the solid states at once. The molecular cage scaffold, which restricts the intramolecular rotations of the TPE moiety, not only helps to preserve the luminescence of TPE in a dilute solution but facilitates the reversible photochromism on account of the intramolecular cyclization/cycloreversion reactions. Furthermore, we demonstrate assorted applications of this multiresponsive molecular cage, e.g., photo-switchable patterning, anticounterfeiting, and selective vapochromism sensing.

A series of novel photo-switchable [2]rotaxanes (i.e., Rot-A-SP and Rot-B-SP before and after shuttling controlled by acid–base, respectively) containing one spiropyran (SP) unit (as a photochromic stopper) on the axle and two tetraphenylethylene (TPE) units on the macrocycle were synthesized via click reaction. Upon UV/visible light exposure, both mono-fluorophoric rotaxanes Rot-A-SP and Rot-B-SP with the closed form (i.e., non-emissive SP unit) could be transformed into the open form (i.e., red-emissive merocyanine (MC) unit) to acquire their respective bi-fluorophoric Rot-A-MC and Rot-B-MC reversibly. The aggregation-induced emission (AIE) properties of bi-fluorophoric TPE combined with MC AIEgens of these designed rotaxanes and mixtures in semi-aqueous solutions induced interesting ratiometric photoluminescence (PL) and Förster resonance energy transfer (FRET) behaviors, which were further investigated and verified by dynamic light scattering (DLS), X-ray diffraction (XRD), and time-resolved photoluminescence (TRPL) measurements along with theoretical studies. Accordingly, in contrast to the model axle (Axle-MC) and the analogous mixture (Mixture-MC, containing the axle and macrocycle components in a 1:1 molar ratio), more efficient FRET behaviors and stronger red PL emissions were obtained from dual-AIEgens between a blue-emissive TPE donor (PL emission at 468 nm) and a red-emissive MC acceptor (PL emission at 668 nm) in both novel photo-switchable [2]rotaxanes Rot-A-MC and Rot-B-MC under various external modulations, including water content, UV/Vis irradiation, pH value, and temperature. Furthermore, the reversible fluorescent photo-patterning applications of Rot-A-SP in a powder form and a solid film with excellent photochromic and fluorescent behaviors are first investigated in this report.

Different photoinactivation ways resulting from different crystal packing may account for different photochromic and fluorescence properties of the title polymorphs.

Abstract Aggregation-induced emission (AIE) active photochromic molecules have attracted growing attention for their versatile applications. Here we designed and synthesized five newly unsymmetrical photochromic diarylethene (DAE) dyads ( BTE1–5 ) by connecting tetraphenylethene (TPE) and aromatic substituent via bithienylethene (BTE) bridge. The chemical structures of those compounds are identified by 1H NMR, 13C NMR and HRMS. The absorption and emission of these dyads were investigated by UV-vis and fluorescence spectroscopy, respectively. The results showed that all those compounds exhibited typically AIE or aggregation-induced emission enhancement (AIEE) characteristic. Particularly, when an aggregation-caused quenching (ACQ) fluorophore (triphenylamine) was grafted to the molecule, connecting with TPE via BTE-bridge, the ACQ phenomenon was dissipated and converted to an AIE luminophore, and those compounds exhibited photochromism upon irradiation with alternative UV and visible light. The solution or solid of those compounds showed distinctly fluorescence switching “ON” or “OFF” observation upon irradiation with alternative UV and visible light. It is interesting that BTE1 could be applied in recording and rewritable information storage, and the cyclization quantum yields could be affected by substituent significantly.

Solid-state stimuli-responsive materials are attracting increasing attention due to their broad prospects in the field of functional materials, but there are still some challenges. We design …

Abstract Most of the reported stimuli-responsive aggregation induced emission (AIE) molecules are single-functioned and it remains highly demanded to integrate multi-stimuli responsive properties in one molecule. A multi-stimuli responsive TPE derivative 1 was synthesized bearing multiple properties including mechanochromism, mechanoluminescence and photochromism. Mechanoluminescence was only shown by the single crystal form, while photochromism was only observed in the amorphous powder. The mechanochromic property of 1 was self-reversible, but can also be accelerated by thermal or solvent vapor treatment. The photochromic property of 1 was easily switched on by a phase transition from crystalline state to amorphous state upon grinding. By a combination of mechanochromism and photochromism, a two-step procedure of color response of 1 was demonstrated upon grinding and UV irradiation. This novel molecule provides an important insight to the development of multi-stimuli responsive materials and advanced anti-counterfeiting materials.

… ) or tetraphenylethylene (TPE) and pyrene unit via dithienlethene (DTE) bridge. Efficient photochromism … in THF/water mixture, the photochromic and fluorescent switching behavior were …

… In this work, three new amphiphilic tetraphenylethylene (TPE) derivatives (TPE-1, TPE-2 and TPE-3) with AIE properties and photochromism were synthesized and investigated. Owing …

Abstract Herein the novel tetraphenylethylene (TPE) derivative 1 was designed with an integration of aggregation‐induced emission (AIE), multi‐state mechanochromism and self‐recovery photochromism. The molecule was susceptible to grinding, heating and vapor fuming and showed corresponding transition of its emission colors. The heated powder or single crystal of 1 exhibited reversible photochromism. After a short period of UV irradiation, it showed a bright red color, but recovered to its original white appearance within 1 min. The photochromism is due to the formation of photocyclization intermediates upon UV irradiation, while the eversible mechanochromism is attributed to the weak molecular interactions derived from head‐to‐tail stacking of the molecules. This reversible multi‐state, high‐contrasted and rapid responsive mechanochromic and photochromic property cooperatively provide double enhancement of a multimode guarantee in advanced anti‐counterfeiting.

… Moreover, due to the better film qualities of polymers, photochromic DAE-based polymers … The aggregation-induced emission (AIE) phenomenon of the tetraphenylethene (TPE) …

… We report the synthesis of a dithienylethene–tetraphenylethene (DTE–TPE) conjugated photochromic fluorophore which simultaneously exhibits aggregation-induced emission and …

Photocyclization of tetraphenylethenes (TPEs) was critical to reveal the underlying mechanism of photochromism of TPE derivatives. To explore the photocyclization process of TPEs, a series of monosubstituted TPE derivatives were designed as model molecules, with substituents (N(CH3)2, NH2, OH, OCH3, COOCH3, CN, and NO2) decorated to the TPE skeleton on meta and para positions, respectively. The photochromic property of the TPE derivatives was explored in DMSO solution and the PMMA matrix, respectively. It showed that TPE derivatives with a meta-substituted group were obviously more susceptible to the photocyclization reaction than their para-isomers. Meanwhile, electron-donating groups are more favorable for facilitating the photocyclization reaction than the electron-withdrawing group. Compared with DMSO, a rigid matrix (PMMA) can effectively elongate the lifetime of radical intermediates and photocyclization intermediates.

Tetraphenylethylene (TPE) derivatives have been a key building block in the development of solid-state fluorophores with tunable emission wavelength and large quantum efficiencies. Recent literature has brought an array of evidence that rotation around the central C=C bond constitutes main route of deexcitation in solution, and that its restriction in solid-state leads to aggregation-induced emission (AIE) in this family of derivatives. However, the influence of substitution on the dynamics of TPEs in solution has so far received little attention, probably because of the difficulty in efficiently separating (E) and (Z) isomers. Here we report the photophysical properties in solution of extended stereopure TPE derivatives. The introduction of triphenylamine (TPA) substituent results in differences in the spectral properties between the (E) and (Z) isomers, thereby allowing modulation of the photostationary state (PSS) and thus switching in the equilibrium between these two forms depending on the irradiation wavelength. Importantly, we show that this photochromism is observed with a very marked decrease in the photoisomerization quantum yields (Φiso) of TPE-TPA, compared to non-extended TPE derivatives, which we attribute to the so called “amino conjugation effect” already reported for several stilbene derivatives. As a generalization of this mechanism, we show that TPA substitution provides similar effect on other stilbenoid derivatives. These results provide important new insight into the photophysics of electron donor substituted TPEs, and their possible use as photochromic materials.

Ensuring the security and reliability of information has increasingly become a key issue for modern society, placing greater demands on encryption technologies and anti-counterfeiting materials. Therefore, the development of intelligent responsive materials with multi-mode encryption and protection capabilities has become crucial. In this study, an aldehyde–amine exchange approach was applied based on the traditional ESIPT–ISO (Excited state intramolecular proton transfer and cis to trans isomerization) color-switching mechanism of salicylaldehyde-aniline Schiff bases. The reaction between tetraphenylethyl salicylaldehyde and aniline derivatives generated eight Schiff base compounds. Five of these compounds displayed UV-triggered color change in the solid phase, whereas the other three exhibited fluorescence emission in solid form. Spectroscopic analysis, theoretical computation, and crystal-structure characterization clarified the mechanisms responsible for both color variation and stability. The stable compounds showed characteristic stacking configurations, and the hydroxyl groups formed weak interactions with nearby atoms, restricting the ESIPT transition and preventing color change under UV irradiation. This work presents the first systematic report on the effect of substituent variation on the ESIPT–ISO process, illustrating how weak interactions and packing modes can inhibit ESIPT. It also represents the first study describing substituent influences on the reverse ESIPT–ISO reaction. Finally, five UV-responsive color-switching materials were developed into color-shifting inks. Through pad and screen printing, these inks enabled encrypted information and anti-counterfeiting features on paper, inorganic, and fiber substrates, maintaining long-term stability for up to three years. Moreover, by utilizing differences in fading times among the photochromic molecules, color-changing inks were overprinted in specific sequences. Upon UV activation, this approach allowed multi-level time-space encryption and anti-counterfeiting of data.

… -photoacid (SPPA) with tetraphenylethene (TPE). The isomerization of SPPATPE can be … is assigned as the local excited emission of TPE moiety, while ROF SPPATPE have two …

Abstract Tetraphenylethene (TPE), a star building block with promising aggregation‐induced emission, has received much interest. Given that its intramolecular Woodward‐Hoffmann cyclic intermediate instantaneously converts back to the original state within several picoseconds, the essentially photochromic characteristic of TPE is little investigated. Achieving a visible photocyclization of TPE is still an unsolved issue and considered as the bottleneck in the further advancement of applications. We report a strategy of attaching carbonate ester onto the TPE skeleton (TPE‐4C) to enhance TPE photocyclization stability. As demonstrated, the incorporated cholesteryloxycarbonyloxy substituents in TPE‐4C can increase the energy barrier for cycloreversion, thereby exhibiting extremely thermal stability of photocyclic intermediate upon UV irradiation, prolonging its lifetime from 63 picoseconds to 46 s by 7.2 × 1011‐fold. The photoinduced cyclization of TPE‐4C could be monitored with naked eyes, and the photocyclization/cycloreversion is achieved by turning on/off UV light along with a relative fatigue resistance. Encapsulation of TPE‐4C into the liquid crystal can induce a striking phase transformation (achiral↔chiral), which can be applicable to encode optical information. Employing carbonate ester into the TPE unit plays a vital role in enhancing the unprecedented TPE photocyclization stability, providing a toolbox to allow TPE‐based photocyclization to be visually monitored.

… TPVT derivatives with various substituents and thoroughly compares their photophysical and photochromic traits… This study proposes a strategy to modulate photochromic properties via …

… We designed and synthesized photochromic fluorescent poly (MMA-co-SPO-co-TPE) nanoparticles with pendant spirooxazine (SPO) dye and tetraphenylethylene (TPE) fuorophores …

Photochromic fluorescent materials have rapidly developed as a new class of intelligent materials, offering a unique combination of traditional photochromic and organic fluorescent materials. These materials possess remarkable photoresponsiveness that can be observed by the naked eye and exhibit fluorescence color change. Consequently, they have found widespread applications in various domains, including molecular switches, logic encryption, medical diagnosis and treatment, and biosensors. Among the multitude of photochromic systems, those based on dithienylethenes (DTEs) have garnered significant attention due to their exceptional photochromic efficiency, commendable reversible photoresponse and fatigue resistance, as well as excellent photostability and thermal stability. Nevertheless, these photochromic fluorescent materials continue to grapple with the issue of aggregation-caused quenching (ACQ), a common problem faced by traditional fluorescent materials. Therefore, the integration of DTE systems with aggregation-induced emission (AIE) systems presents a promising solution to tackle this predicament, enabling an improved quantum yield for photochromic fluorescent materials in their aggregated state and broadening their range of applications. This review comprehensively summarizes and evaluates the construction strategies and application prospects of DTE-based photochromic AIE luminogens (AIEgens) in recent years, while also providing an outlook on their future development.

… 2F1Br, 2Cl1Br and 3Br show excellent photochromic property in both single-molecule state and aggregated state. Notably, the triphenylethylene compounds exhibit significant …

Organic photochromic materials present extraordinary value and exciting prospects in numerous photo-controlled practical applications; however, it is still a great challenge to achieve multiple-wavelength-controlled multicolor photochromism with dual-mode readout. Herein, we propose a general design strategy to achieve multicolor photochromic systems with dual-signaling color and fluorescence modes through a group of colorful photochromic compounds based on an AIE-active molecular skeleton. It is found that combining photochromic and fluorescent systems and designing the proper module composition of the functional subunits in an AIE-active molecule can regulate the molecule toward predominant photophysical emission or photochemical chromism in a controllable way, and multicolor photochromism can be accomplished using multicomponent mixtures with well-separated and individually addressable absorption bands by regulating the conjugation of the introduced photoactive units. The photo-triggered photochromism is attributed to the reversible cyclization/cycloreversion reaction, and the extended conjugation of the photoactive unit is the dominant contributor to the colorful coloration of the different chromophores, which ranges from red to blue. Variation of the conjugated structures of the photoactive unit not only endows these compounds with multiple-wavelength-triggered color control, but also enables the colored isomers to be decolored using visible light stimuli with distinct wavelengths, which allows the multiplexing optical systems to work in a more flexible and controllable way in advanced photo-controlled patterning and anti-counterfeiting applications.

Photochromic materials have attracted widespread attention due to their potential applications in optical information storage, optoelectronic devices, and fluorescence probes. As a typical photochromic system, diarylethene derivatives are considered one of the most promising photochromic materials due to their outstanding photostability and significant bistable properties. Based on an aggregation-induced emission (AIE) mechanism, this study employed a molecular structural engineering strategy to design and synthesize a series of diarylethene derivatives containing ethyl benzoate substituents. A systematic investigation of the structure–activity relationship between their photochromic behavior and AIE characteristics revealed a dual-state light response mechanism in the solid and solution states. This study demonstrates that the target compounds exhibited significant photochromic responses under UV–visible light irradiation, with enhanced emission in the solid state compared to the solution state, confirming the remarkable enhancement effect of AIE on aggregation. Structural characterization techniques such as nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectrometry (H RMS) were employed to elucidate the correlation between molecular conformation and photophysical properties. Furthermore, these materials demonstrated potential for multi-level anti-counterfeiting, high-density optical storage, and bioimaging applications, providing experimental foundations for the development of novel multifunctional photochromic materials.

… in DAE based photochromic AIE materials showing enhanced … DAE materials without AIE effect, the AIE-based photochromic … the photochromism reaction induced by UV/Vis irradiations. …

Photochromic materials have been drawing considerable attention owing to their potential applications including optical devices, logic gates, data recording and storage, and chemosensors. However, most conventional photochromic compounds usually suffer from aggregation-caused quenching (ACQ), and the solid or aggregate state is often required for practical applications. The introduction of the aggregation-induced emission (AIE) property into photochromic systems not only relieves the limitation posed by the ACQ phenomenon, but also endows photochromic systems with more fascinating fluorescence properties. Therefore, novel classes of AIE-active photochromic materials have been reported and considerable efforts have been continuously devoted towards improving their functions and performances for matching the requirements of practical applications. This review systematically describes recent progresses made in the AIE-active photochromic materials with respect to molecular structures, material morphologies, and practical applications, while the principle of molecular design and mechanism of performance are also covered. Moreover, the challenges, emerging fields, development tendency, and some perspectives for AIE-active photochromic materials are discussed and presented.

Stimuli‐responsive fluorescent materials with aggregation‐induced emission (AIE) characteristics have attracted increasing attention owing to their advantages of bright fluorescence in the solid state and the ability to tune the structures and physicochemical performances in response to various stimuli. Among all the available external stimuli, light stands out, and has rapidly become a focus of research, because it offers green and remote triggering, noninvasive manipulation, high spatiotemporal resolution, and convenient tunable properties. Consequently, photo‐responsive AIE materials provide a fascinating strategy for constructing functional fluorescent materials. This review summarizes the recent advances in the fabrication of photo‐responsive fluorescent materials with AIE characteristics by grafting AIE fluorogens (AIEgens) into photochromic molecules. State‐of‐the‐art photo‐responsive AIE materials based on the inherent photochemical reactions of AIEgens are highlighted, and are classified and discussed according to the photochemical pathways, including photocyclization, photo‐isomerization, photodimerization, photo‐removal, and multiple photoreactions. Following this, the corresponding applications of photo‐responsive AIE materials in bio‐imaging, anti‐counterfeiting, photo‐patterning, photo‐release of chemicals or drugs, and photo‐controlled assembly and disassembly are introduced. Finally, the most promising directions for development and applications of photo‐responsive AIE materials are outlined and discussed.

Photo‐triggered chromism has emerged as critically important in materials for advanced soft photonic devices. The conventional photochromic units with reversible color change between two isomers are unstable either thermally or photochemically, which is an important challenge for long‐standing optical devices. Here, a novel photo‐enhanced coordination mechanism leading to stable chromism is reported. Upon tethering the aggregation‐induced emission (AIE) moiety diphenyldibenzofulvene (PBF) to a dicarboxylic pyridine group, photo‐irradiation triggers the coordination transition between the carbonate groups and Mg2+ from bidentate to the more stable bridging mode, which further influences the conformation of the remote PBF group, leading to transition of the emission color from cyan to yellow. Under ambient conditions, both coordinating isomers display excellent thermal and photochemical stability. As a result, the photo writings on the films based on the coordinating AIE materials exhibit the long‐term stability, which barely fades even upon heating, vapor fuming, or day‐light exposure. This photo‐enhanced‐coordination enabled bistable chromism is expected to open a new vista in the study of chromism and high durable optical memories.

A couple of gated photochromic molecules TrPEP and TrPEPO with AIEgen have been rationally designed and synthesized. No photochromism is detected for TrPEP whilst TrPEPO shows obvious photochromic properties in the solution state. By adding equimolar H2O2 aqueous solution to the TrPEP solution, the photochromic properties would be quickly turned on. The oxidation reagent acts as a gate to switch the photochromic properties by switching the triphenylphosphine group to a triphenylphosphine oxide group. Both TrPE and TrPEO display typical AIE phenomena. Different intensive emission bands with the emission maxima of 500 nm and 455 nm are detected before (TrPEP) and after (TrPEPO) oxidization in solid states. Combining the AIEgens, photochromic ON/OFF states can be easily indicated by the different emission colors in the solid state. Single crystal analyses and TD-DFT calculations were carried out to further investigate the photophysical and photochromic properties of these compounds. These new triphenylethylene derivatives provide a new strategy to achieve gated photochromic materials with simple chemical structures and gate indicators.

Reversible photochromic molecules with solid-state fluorescence are of great value and perspective in various surface-involved practical applications. Herein, we propose a general strategy to design reversible photochromic molecules with solid-state fluorescence by introducing photoactive thienyl and benzothienyl groups into an AIE-active molecular skeleton. The combination of a thienyl or benzothienyl group and a triphenylethene in the right manner enables the molecules to possess unique aggregation-induced emission properties and reversible photo-controlled changes in color and fluorescence in solid state. Theoretical analysis reveals that photo-triggered cyclization and cycloreversion reactions are responsible for the reversible photochromism and photoinduced fluorescence switching, and the enlargement of the conjugation of the introduced photoactive units can significantly promote the cyclization reactions and the photochromic processes. The excellent performance of these photochromic molecules with aggregation-induced emission activity in a photoswitchable patterning paper and multiple encryption of anti-counterfeiting of a banknote demonstrates that they are perfectly suited for surface-involved photo-controlled applications such as information storage and data encryption.

The proposal of the aggregation-induced emission (AIE) effect shines a light on the practical application of luminescent materials. The AIE-active luminescence microgels (TPEC MGs) with photo-induced color-changing behavior were developed by integrating positively charged AIE luminogens (AIEgens) into the anionic network of microgels, where AIEgens of TPEC were obtained from the quaternization reaction between tetra-(4-pyridylphenyl)ethylene (TPE-4Py) and 7-(6-bromohexyloxy)-coumarin. The aqueous suspensions of TPEC MGs exhibit a significant AIE effect following the enhancement of quantum yield. In addition, further increase in fluorescence intensity and blueshift occur at elevated temperatures due to the collapse of microgels. The distinctive photochromic behavior of TPEC MGs was observed, which presents as the transition from orange-yellow to blue-green color under UV irradiation, which is different from TPEC in good organic solvents. The phenomenon of color changing can be ascribed to the competition between photodimerization of the coumarin part and photocyclization of TPE-4Py in TPEC. The photochromic TPEC MG aqueous suspensions can be conducted as aqueous microgel inks for information display, encryption, and dynamic anticounterfeiting.

It is extremely challenging to design photo-controlled molecular switches with absorption and fluorescence dual-mode outputs that are suited for solid surface and interface. Herein, we report a group of furan-containing tetraarylethene derivatives with unique photophysical behaviour of aggregation-induced emission and distinct photochemical reaction-triggered photochromic behaviours by combining photoactive furan or benzofuran group and an AIE-active triphenylethene molecule. The introduction of a furyl or benzofuryl group into the AIE luminogen endows the molecules with significant reversible photochromism and solid-state fluorescence. The coloration and decoloration of these molecules can be switched by respective irradiation of UV and visible light in a reversible way, and the photochromic changes are accompanied by switch-on and switch-off of the solid-state fluorescence. It is revealed that the photo-controlled cyclization and cycloreversion reactions are responsible for the reversible photochromism and fluorescence switching from experimental data and theoretical analysis. Both the position and conjugation of the introduced photoactive units have significant influences on the color and strength of the photochromism, and the simultaneous occurrence of photoinduced fluorescence change in solid state is perfectly suited for surface-involved applications. The demonstrations of dual-mode signaling in photoswitchable patterning on a filter paper and anti-counterfeiting of an anti-falsification paper strongly highlight the unique advantage of these photochromic molecules with aggregation-induced emission characteristic in various practical applications. This work proposes a general strategy to design photochromic molecules with AIE activity by introducing photoactive functionals into an AIEgen, and demonstrates incomparable advantage in dual-mode signaling and multifunctional applications of these molecules.

Photoswitchable fluorescent self‐assemblies exhibiting aggregation‐induced emission (AIE) properties have garnered widespread attention. Due to their great adaptiveness and responsiveness towards different wavelengths required by photoreaction, photo‐isomerization, and photoluminescence excitation, these fluorescent self‐assemblies show diverse emission behavior in a spatial, temporal, and polychromatic manner. Integrating organic photoswitches and AIE fluorophores, these photoluminescent nano‐assemblies has been proven to be an effective approach, allowing the development of sophisticated systems for drug release and cell regulation that can be precisely manipulated through light or other stimuli. This review systematically encapsulates recent advances in photoswitchable fluorescent self‐assemblies under multi‐scenario biological applications. The construction of photoswitchable AIE fluorophores through covalent and non‐covalent interactions and their multimodal regulation are detailed, along with their biological applications in biosensing, bioimaging, and drug therapy.

Photoswitchable molecules exhibit remarkable advantages, including rapid response, reversibility, and fatigue resistance, and hold tremendous potential for applications in fields such as anti-counterfeiting, super-resolution imaging, optical information storage, and sensing. Compared to their solution-state counterparts, solid-state fluorescent photoswitches offer advantages such as enhanced stability and ease of processing/integration, representing a more desirable form for practical applications. However, the restricted molecular packing in the solid state often hinders the photoisomerization of the photochromic units, leading to compromised photochromic performance. The integration of aggregation-induced emission (AIE) motifs with fluorescent photoswitches is an effective strategy for achieving high-performance solid-state fluorescent photoswitches. The twisted conformations of AIE luminogens (AIEgens) provide the necessary spatial freedom for the photoisomerization of the photochromic units in the solid state, thereby successfully overcoming the limitations imposed by molecular packing and enabling efficient solid-state fluorescent photoswitching. This review summarizes the representative types of solid-state fluorescent photoswitchable molecular systems developed in recent years based on this strategy, along with their applications. It aims to provide guidance for the design of novel solid-state photoswitchable systems and is significant for deepening the understanding of their stimulus-responsive mechanisms, developing new materials, and expanding their application scope.

… with the 12/PVP/PDMS hybrid film using blue light and heat … unit and TPE is a typical AIE-active molecule, thus, most TPE-… molecules by introducing two diarylethene groups to one AIE …

… , such as organic spiropyrans and diarylethenes,[2] inorganic … TPEs share the properties of thermoplastics and elastomers, … report on WO 3 hybrid photochromic TPEs. We successfully …

We present the rational design and synthesis of an innovative tricolor photochromic switch featuring a unique molecular architecture combining an E-tetra-arylethene core with dual …

… with poor water solubility of TPE derivatives, a series of water-soluble TPE derivatives were … the four benzene ring positions of TPE molecules. These TPE derivatives exhibit cyan-blue …

Isolation of E-1,2-bis(4-bromophenyl)-1,2-diphenyl-ethylene from the E/Z isomer mixture obtained by a McMurry coupling reaction and reaction of this isomer with imidazole followed by N-alkylation with nBuBr and anion exchange yielded the bisimidazolium tetraphenylethylene (TPE) derivative H2-E-1(PF6)2. The reaction of H2-E-1(PF6)2 with Ag2O yielded the di-nuclear metallarectangle [Ag2(E-1)2](PF6)2 where the two bis-NHC donors E-1 bridge two silver atoms. Irradiation of [Ag2(E-1)2](PF6)2 leads to E/Z isomerization of the di-NHC ligand and formation of Z-1 in the mononuclear complex [Ag(Z-1)]PF6. Demetallation of the di-NHC ligand with NH4Cl/NH4PF6 yielded bisimidazolium salt H2-Z-1(PF6)2. The unique isomerization of the E-TPE derivative into its Z-isomer via metal complex formation/irradiation/demetallation cannot be achieved by irradiation of the individual imidazolium salt. The emissive properties of the TPE complexes [Ag2(E-1)2](PF6)2 and [Ag(Z-1)]PF6 have been investigated.

… and important applications, synthesis and separation techniques that can lead to a pure isomer, as well as techniques that can control the reversible isomerization, are highly intriguing. …

Configuration-controllable E/Z isomers based on tetraphenylethene were prepared with a facile and effective method. First, compounds 1 and 2, configuration-controllable precursors of E/Z isomers, were synthesized. Then, pure E/Z isomers were obtained via Suzuki reaction, avoiding the difficulties of separation. The conformational changes of E/Z isomers can occur through photoactivation. Importantly, red-shifts of 66 nm from 6 (E-) to 3 (Z-) and 58 nm from 7 (E-) to 4 (Z-) were observed remarkably on the photoluminescence (PL) emission spectra. The Z isomer showed a longer fluorescence lifetime compared with the E isomer. The Z isomers 3 and 4 exhibited piezofluorochromism under grinding, whereas the E isomers 6 and 7 showed no such behaviors. The E isomer has better thermal stability than the Z isomer. Lastly, graphene-like molecules were synthesized with the FeCl3/CH3NO2 system. The E and Z isomers after oxidation showed negligible differences in the PL emission spectra because the effective conjugated lengths of oxidized E and Z isomers were both extended. Furthermore, the fabricated field-effect transistors showed nice performance with mobilities of 0.92 and 1.14 cm-2 V-1 s-1 at low operating voltages, respectively.

… isomerization equilibria and fluorescence properties were investigated. In addition to their pronounced AIEE behavior, 4 and 8 also showed various reversible … The tetraphenylethylene (…

… Two isomeric star-shaped dyes (M1, M2) with tetraphenylethylene … reversal directly driven by core isomerization. Both isomers responded … Solid-state M2 further demonstrated reversible …

It is extremely significant and desirable to integrate the fascinating mechanochromism and photochromism in one simple molecule. Herein, two intriguing cyanostilbene‐containing triphenylamine (TPA)/tetraphenylethylene (TPE) derivatives (Z‐TPA‐MB and Z‐TPE‐MB) are elaborately designed, which not only display excellent aggregation‐induced emission (AIE) properties with high solid‐state fluorescence quantum yields (60.9% and 63.8%) but also exhibit reversible and high contrast mechanochromism and distinct photochromism. The powders of Z‐TPA‐MB and Z‐TPE‐MB both exhibit large red‐shift under mechanical stimulation based on the highly twisted conformation and the resulting loose packing mode, accompanied by significant changes in apparent and fluorescent colors. Meanwhile, their solid‐state fluorescence can be reversibly switched between crystalline and amorphous structures through alternating grinding and solvent fuming, exhibiting good fatigue resistance. In addition, the molecules also exhibit distinct dual‐mode photochromic behaviors owing to the presence of cyanostilbene moieties: under 420/365 nm light irradiation, the fluorescence of which decreases in solution owing to the photo‐isomerization, while decreases and blue‐shifts in the aggregated state owing to the photodimerization reactions. The reversible, tractable, and high‐contrast mechanochromism and distinct photochromism of the cyanostilbene‐containing molecules endow them with excellent application prospects in the field of rewritable papers and photo‐patterning.

Organic photochromic materials have always been a hot topic among scientists, ascribed to its broad applications and characteristic properties of photo-modulating multicolor photoluminescence. Meanwhile, white-light emission of organic materials has drawn considerable attention in recent years. Herein, these two concepts are combined together to make an achievement in a photochromic copolymer with white-light emission. A novel amorphous polyacrylamide copolymer consisting of tetraphenylethylene (TPE) and spiropyran (SP) monomers is synthesized, which is capable of emitting fluorescence with tunable colors including white-light one with Commission Internationale de L'éclairage coordinates (0.33, 0.33). This new concept provides an available approach to obtain white-light emission materials which will exert far-reaching influence in its further development.

… -type intramolecular photocyclization in the crystalline state. In addition, we report for the first time morphology-dependent photochromism, in which the photochromic … the solid-state and …

… application in optical data storage (ODS) of tetraphenylethene (TPE)-… We recorded data points inside the TPE-doped … the possibility of utilizing the TPE-doped photopolymer as chemical …

… These properties are ideal for making data storage, biological/chemical sensors, and photoelectric … experiments, we believe TPE-(C3Br)4 can be applied in data protection purposes. …