摘要:Mechanical-responsive organic luminogens have potential applications in the fields of information encryption, optical storage, pressure sensors, etc. due to their unique luminescent properties, and have attracted widespread attention. Their luminescent properties are not only derived from the single-molecule structure, but also closely related to the different stacking modes of molecular aggregates. Therefore, how to control the molecular stacking mode becomes a key issue for obtaining functional luminescent materials. This review mainly focuses on the material system of mechanochromism and mechanoluminescence, outlines several strategies to regulate the intermolecular interactions, and highlights the relationship between molecular stacking and luminescent performance, which paves a new way to design novel luminescence materials and further promotes the development of organic luminescent materials.
摘要:A derivative of hexathiobenzene, named hexathiobenzene hexapyridine(6SB6Py) that can exhibit a photocontrolled aggregation-induced emission(AIE) behavior in organic phase, was prepared by a multi-step synthesis method. This compound can be dispersed in organic solvents DMF and DMSO with barely glows. However, the emission intensity is enhanced by 5 to 10 times after 365 nm irradiation. Among them, the DMF solution of 6SB6Py shows a single peak emission at 500 nm, whereas the DMSO solution of 6SB6Py has double emission peaks at both 420 nm and 500 nm. The almost unchanged 1H NMR signal before and after irradiation indicates that 365 nm light has not caused a traditional photochemical reaction of this system. Dynamic light scattering data also show the aggregation size of 6SB6Py in the solution is changed with the increase of irradiation time. It suggested that the effect of photoinduced molecular realignment caused the enhanced emission of 6SB6Py by external light in organic solutions, instead of a photochemical reaction.
摘要:A new aggregation-induced emission(AIE) molecule of triphenylvinylacetylene gold triphenylphosphine complex(1) was designed and synthesized in this work. 1 showed no emission in DMSO solution but intense emission in solid state, suggesting a typical AIE property. The AIE property of 1 was proven to be originated from a restriction of intramolecular rotation(RIR) mechanism. A fluorescence "turn-off" response of 1 for Hg2+ ion was observed in aqueous solution, which exhibited good selectivity and anti-interference property.
摘要:Aggregation-induced emission(AIE) luminogens have attracted considerable attention for its important role in supramolecular chemistry, biology and materials science, especially, those with water-solubility which were highlighted because of the application in the internal environment of biological organism or natural environment. In this work, a water-soluble AIE molecule() with dicyanodistyrylbenzene(DCS) as the luminescent moiety and sulfonic group as the hydrophilic unit was synthesized, and its optical properties were systematically studied. Spectroscopic studies suggested that the addition of the poor solvent acetonitrile to the aqueous solution caused the formation of nanoparticles and the AIE phenomena were demonstrated. Furthermore, as the sulfonic group has the ability to bind protons reversibly, the absorption peaks of DCS-SO were blue-shift after the addition of acid. Moreover, the color change process was reversible upon pH change. By making use of the AIE property and chemical reactivity towards OH-/H+, is able to respond pH within the pH range from 1 to 13 by showing different emission colors and intensities: strong to weak blue emission within the pH range from 1 to 7 and weak blue emission to strong orange emission within the pH range from 8 to 13. According to AIE mechanism, the reason for pH-mediated optical properties of was studied. Therefore, is a new material with the AIE and pH-responsive properties.
摘要:Rapid detection of food contaminants is essential for preventing foodborne diseases and ensuring food safety. Fluorescence sensors with high selectivity, sensitivity and rapid responsibility exhibit superior advantages than common detection methods. Aggregation-induced emission luminogens(AIEgens) emit weakly in the molecular or dispersed state while exhibit strong fluorescence in the aggregated state, which effectively overcome the limitation caused by aggregation-caused quenching(ACQ) effect. AIEgens have been extensively applied in food safety detection because of its unique "off-on" fluorescence, ignorable background fluorescence, large Stokers shift and excellent photostability. In this article, the applications of AIEgens sensors for pesticides, veterinary drugs, heavy metals, pathogens, food additives and the detection mechanisms were reviewed. Finally, the existing problems and future developments were also summarized and prospected.
摘要:Metal nanoclusters with enhanced aggregation-induced emission(AIE) have shown a broad application prospect in the bio-medical fields and environmental science. However, the current researches on AIE metal nanoclusters are still in the initial stage. The complex surface/interface structure and enhanced luminescence mechanisms are still not clear. Moreover, it remains a big challenge to prepare AIE metal nanoclusters with properly regulated properties. Following the reports that successfully synthesized metal clusters with AIE characteristic, this review firstly summarized the surface modification strategies with mercaptan and the AIE mechanism of gold, silver, copper nanoclusters, and introduced their biomedical applications. Then, the preparation and bio-application of unique iridium complexes with AIE property are also discussed. Finally, the research status and prospects of AIE metal nanoclusters are described. In sum, this review aims to provide concepts for the future research and development of AIE metal nanoclusters.
摘要:Aggregation-induced emission(AIE) probes have shown great potential in cancer diagnosis and therapy due to their excellent sensitivity and photo-stability. Mitochondria, which is regarded as one of the most important organelles in cells, has obvious difference between cancer cells and normal cells. Thus, it is reliable to utilize mitochondria-targeted AIE probes to distinguish cancer from normal cells. In this review, we exhibit the design principle and imaging mechanism of AIE probes for mitochondria target, and their distinguishing imaging between cancer cells and normal cells, circulating tumor cells and leukocyte, and dual identification imaging of cancer cells and related bacteria. The probes show remarkable advantages in cancer diagnosis, surgical navigation, cancer treatment assessment and recurrence monitoring, and cell pollution evaluation. We hope, this review will motivate to develop more AIE probes with rich properties and conduct deeper researches to promote the rapid development of biomedical field and maintain human health.
摘要:Phototheranostics involving the ingenious integration of light-triggered diagnostics and therapeutics has been recognized to be potentially powerful for disease treatment as it provides high temporal and spatial selectivity, low side effects, high therapeutic effectiveness and controllability. Benefiting from the appreciable biosafety, tuneable photophysical properties, facile processability and functionalization, excellent fluorescence and photosensitizing performances, as well as the feasibility in building multimodal phototheranostic agents, luminogens with aggregation-induced emission(AIE) nature have achieved great breakthrough in the field of phototheranostics over the past few years. This review summarizes the state-of-the-art advancements of AIE luminogens in phototheranostic applications mainly referring to fluorescence imaging-guided photodynamic therapy, photoacoustic imaging-guided photothermal therapy, and multimodal imaging-guided synergistic therapy on the basis of the precise molecular engineering and subtle regulation of molecular aggregation behaviors. Additionally, a brief conclusion and perspectives for the future of this field are also presented at the end of this review.
摘要:Organic radicals have unique ground state open-shell electronic structures, arising from the presence of unpaired or weakly bonded electrons. Such molecular systems generally exhibit special physical properties, such as near-infrared absorption, nonlinear optical response, reversible redox, magnetic properties and etc., and may become the next generation of optoelectronic and magnetic materials. However, among organic radicals, the majority of them have strong non-radiative channels to release photoexcited energy, and thus display extremely weak or no luminescence. In recent years, doublet radicals, exemplified by derivatives of triarylmethyl radical, show attractive luminescent property, and their red emission with fluorescence quantum yield even up to 90% are impressive, and they are promising material candidates for application in organic light-emitting diodes(OLEDs). Radical luminophore is defined as a new type of luminescent chromophore with open-shell character at both the ground state and excited state. The difficulties in radical luminohpore are how to design new radicals and to tune their luminescent properties. Importantly, more radical luminophores with selectivity of color displays and high luminescence efficiencies are highly desirable in this research area. For this, we give a short review of the radical luminophores relative to molecular structures, physical properties and the relationship between structure and property, together with furthermore discussion of excited-state luminescence mechanism and suppression of non-radiative transition, as well as expects and challenges in future.
关键词:radical luminophore;structure-property relationship;modulation of excited-state;luminescence efficiency;aggregation state