Macromolecules with aggregation-induced emission (AIE) attributes are a class of luminescent materials that display enhanced emission when they are aggregated. They have attracted much attention ...because of their good solubility, processability, high emission efficiency in the aggregated states,
etc.
A large variety of AIE macromolecules have been developed, showing exponential growth of research interest in this field. This review summarizes the design principles and recent synthetic advancements, topological structures, as well as the frontiers of functionalities and potential applications of AIE macromolecules, especially fluorescence sensing, biological applications and optoelectronic applications, with an emphasis on the recent progress. New luminogenic systems without conventional chromophores displaying aggregated state emission are discussed. The highly dense clusters of heteroatoms with lone pair electrons in these systems may serve as the chromophore and are cited as "heterodox clusters". It is expected that the mechanistic insights into the AIE phenomena, based on the restriction of intramolecular motions and structure rigidification, can guide the future design of AIE materials with fascinating structures and functionalities.
A comprehensive review of macromolecules with aggregation-induced emission attributes is presented, covering the frontiers of syntheses, structures, functionalities and applications.
Aggregation‐induced emission (AIE) has been harnessed in many systems through the principle of restriction of intramolecular rotations (RIR) based on mechanistic understanding from archetypal AIE ...molecules such as tetraphenylethene (TPE). However, as the family of AIE‐active molecules grows, the RIR model cannot fully explain some AIE phenomena. Here, we report a broadening of the AIE mechanism through analysis of 10,10′,11,11′‐tetrahydro‐5,5′‐bidibenzoa,d7annulenylidene (THBDBA), and 5,5′‐bidibenzoa,d7annulenylidene (BDBA). Analyses of the computational QM/MM model reveal that the novel mechanism behind the AIE of THBDBA and BDBA is the restriction of intramolecular vibration (RIV). A more generalized mechanistic understanding of AIE results by combining RIR and RIV into the principle of restriction of intramolecular motions (RIM).
Luminescence turn‐on: Through theoretical calculations to explain empirical observation, it is now possible to more fully explain the phenomenon of aggregation‐induced emission. By comparing tetraphenylethene and its structurally similar analogues, deeper insight has been gained into this photophysical phenomenon in which luminescence can be turned on in the aggregated or solid state.
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Cisplatin is a platinum containing drug first approved as an antineoplastic agent in 1978. It remains an important and effective therapy in many forms of cancer today. Cisplatin mediates its ...tumorcidal effects via a number of different cytotoxic mechanisms. Although it is best known for DNA damage, cisplatin also causes cytoplasmic organelle dysfunction particularly with the endoplasmic reticulum and mitochondria. It also activates apoptotic pathways and inflicts cellular damage via oxidative stress and inflammation. One of its dose limiting toxicities is its effects on the kidney. This includes acute kidney injury as well as tubular injury resulting in electrolyte wasting. Extensive research has found that cisplatin entry into a cell is facilitated by a number of cellular transporters including human copper transport protein 1 (Ctr1) and the organic cation transporter 2 (OCT2) which are expressed on renal tubular cells. The interactions between the mechanisms of cytotoxicity and cellular transport play an important role in the nephrotoxicity. Better understanding of these interactions could one day help devise better renoprotection that would not reduce its anti-tumor effects.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Heterocyclic polymers have gained enormous attention for their unique functionalities and wide applications. In contrast with the well-studied polymer systems with five- or six-membered heterocycles, ...functional polymers with readily openable small-ring heterocycles have rarely been explored due to their large synthetic difficulty. Herein, a facile one-pot multicomponent polymerization to such polymers is developed. A series of functional polymers with multisubstituted and heteroatom-rich azetidine frameworks are efficiently generated at room temperature in high atom economy from handy monomers. The four-membered azetidine rings in the polymer skeletons can be easily transformed into amide and amidine moieties via a fast and efficient acid-mediated ring-opening reaction, producing brand-new polymeric materials with distinctive properties. All the as-prepared azetidine-containing polymers exhibit intrinsic visible luminescence in the solid state under long-wavelength UV irradiation even without conventionally conjugated structures. Such unconventional luminescence is attributed to the clusteroluminogens formed by through-space electronic interactions of heteroatoms and phenyl rings. All the obtained polymers show excellent optical transparency, high and tunable refractive indices, low optical dispersions and good photopatternability, which make them promising materials in various advanced electronic and optoelectronic devices. The ring-opened polymers can also function as a lysosome-specific fluorescent probe in biological imaging.
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Building humidity sensors possessing the features of diverse‐configuration compatibility, and capability of measurement of spatial and temporal humidity gradients is of great interest for highly ...integrated electronics and wearable monitoring systems. Herein, a visual sensing approach based on fluorescent imaging is presented, by assembling aggregation‐induced‐emission (AIE)‐active molecular rotors into a moisture‐captured network; the resulting AIE humidity sensors are compatible with diverse applications, having tunable geometries and desirable architectures. The invisible information of relative humidity (RH) is transformed into different fluorescence colors that enable direct observation by the naked eyes based on the twisted intramolecular charge‐transfer effect of the AIE‐active molecular rotors. The resulting AIE humidity sensors show excellent performance in terms of good sensitivity, precise quantitative measurement, high spatial–temporal resolution, and fast response/recovery time. Their multiscale applications, such as regional environmental RH detection, internal humidity mapping, and sensitive human‐body humidity sensing are demonstrated. The proposed humidity visualization strategy may provide a new insight to develop humidity sensors for various applications.
Humidity visualization is achieved by incorporating aggregation‐induced‐emission (AIE)‐active molecular rotors into a moisture‐capture network. The resulting sensing materials are compatible with diverse configurations for multiple applications, and show excellent performance in terms of good sensitivity, precise quantitative measurement, high spatial–temporal resolution, and fast response/recovery time. This visual strategy provides a new avenue to develop humidity sensors for future highly integrated systems.
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The development of molecular machines requires new building blocks which are easy to characterize and visualize to realize a complexity comparable to their natural counterparts such as biological ...enzymes. Furthermore, with the desire to build functional nanobots capable of navigating living organisms, it is necessary that the building blocks show mobility even in the solid state. Herein we report a system which is emissive in the amorphous state but is non‐fluorescent in the crystalline state due to the formation of extensive π‐π interactions. This dual nature could be exploited for easy visualization of its solid‐state molecular rearrangement. The emission of the amorphous film was quenched as the molecules spontaneously formed π‐π interactions even in the solid state. Scratching the non‐emissive film destroyed the interactions and restored the emission of the film. The emission quickly disappeared with an average lifetime of 20 s as the compound reformed the π‐network even at room temperature.
Beacons lit by molecular motion: Intermolecular forces drive the formation of π‐π interactions even in the solid state. Shear forces/scratching disrupt the interactions, turning on emission. The quenched π‐π‐interactions quickly reform even in a film, allowing the visualization of the molecular motions. Theoretical calculations show that the formation of π‐interactions is highly favorable and driving this motion.
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π-Bonds connected with aromatic rings were generally believed as the standard structures for constructing highly efficient fluorophores. Materials without these typical structures, however, exhibited ...only low fluorescence quantum yields and emitted in the ultraviolet spectral region. In this work, three molecules, namely bis(2,4,5-trimethylphenyl)methane, 1,1,2,2-tetrakis(2,4,5-trimethylphenyl)ethane, and 1,1,2,2-tetraphenylethane, with nonconjugated structures and isolated phenyl rings were synthesized and their photophysical properties were systematically investigated. Interestingly, the emission spectra of these three molecules could be well extended to 600 nm with high solid-state quantum yields of up to 70%. Experimental and theoretical analyses proved that intramolecular through-space conjugation between the “isolated” phenyl rings played an important role for this abnormal phenomenon.
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Long-persistent luminescence (LPL), also known as afterglow, is a phenomenon in which the material shows long-lasting luminescence after the cessation of the excitation source. The research of LPL ...continues to attract much interest due to its fundamental nature and its potential in the development of the next generation of functional materials. However, most of the current LPL materials are multicomponent inorganic systems obtained after harsh synthetic procedures and often use rare-earth metals. Recently, metal free organic long-persistent luminescence (OLPL) has gained much interest because it can bypass many of the disadvantages of inorganic systems. To date, the most successful method to generate OLPL systems is to access charge-separated states through binary donor–acceptor exciplex systems. However, it has been reported that the ratios of the binary systems affect OLPL properties, complicating the reproducibility and large-scale production of OLPL materials. Simpler OLPL systems can overcome these issues for the benefit of the development and adoption of OLPL systems. Here, we report on the rational design and synthesis of a single-component OLPL system with detectable afterglow for at least 12 min under ambient conditions. This work exemplifies an easy design principle for new OLPL materials. The investigation of the material provides valuable insights toward the generation of OLPL from a single-component system.
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Because of their innate ability to store and then release energy, long‐persistent luminescence (LPL) materials have garnered strong research interest in a wide range of multidisciplinary fields, such ...as biomedical sciences, theranostics, and photonic devices. Although many inorganic LPL systems with afterglow durations of up to hours and days have been reported, organic systems have had difficulties reaching similar timescales. In this work, a design principle based on the successes of inorganic systems to produce an organic LPL (OLPL) system through the use of a strong organic electron trap is proposed. The resulting system generates detectable afterglow for up to 7 h, significantly longer than any other reported OLPL system. The design strategy demonstrates an easy methodology to develop organic long‐persistent phosphors, opening the door to new OLPL materials.
A novel approach to achieve a pure organic long‐persistent luminescent material using a phosphonium salt doped with dimethylaniline is reported. The doped crystals can exhibit a green afterglow emission lasting up to 7 h after the cessation of UV excitation. The positive phosphonium salt holds and protects the separated charge to produce unprecedented afterglow duration.
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