Materials taking abundant advantage of triplet states luminescence have risen lots of attention in decades. In this work, a Cu(I) metal‐organic framework (MOF) with synchronous metal‐to‐ligand charge ...transfer (MLCT) state and triplet emission of the ligand is synthesized from a D–π–A–π–D ligand with suitable energy gap. The Cu(I) MOF possessed MLCT emission in the range of 450–505 nm with microsecond lifetimes (1.07 to 5.38 µs) and a triplet state emission in near infrared (NIR) region ≈705 nm with lifetimes of 1.85 ms at 300 K and 25.16 ms at 77 K, much longer than those of reported Cu(I) MOFs. Moreover, a white light is obtained through adjusting the relative intensity of dual peaks. More importantly, NIR long persistent luminescence of Cu‐MOF is observed by naked eyes under cryogenic condition. Multiple factors such as the delicate design of the D–π–A–π–D structure of ligand, the enhanced spin‐orbital coupling by Cu(I) networks, and the tight packing mode of the framework promote the generation of MLCT emission and ultralong NIR room temperature phosphorescence. The combination of calculation and experiment to analyse the luminescence mechanism of Cu(I) MOFs provides ideas for the development of Cu(I)‐based intelligently responsive materials with RTP properties.
The D–π–A–π–D structure of Tz‐Nap ligand with appropriate ΔEST is cleverly designed, which further self‐assembly with copper(I) to enhance spin‐orbital coupling. The tight packing mode of the framework promoted the generation of metal‐to‐ligand charge transfer emission and ultralong near infrared (NIR) room temperature phosphorescence. This is the first time that considerable NIR long persistent luminescence has been achieved in copper(I) metal‐organic frameworks at low temperature.
Materials with tunable long persistent luminescence (LPL) properties have wide applications in security signs, anti‐counterfeiting, data encrypting, and other fields. However, the majority of ...reported tunable LPL materials are pure organic molecules or polymers. Herein, a series of metal‐organic coordination polymers displaying color‐tunable LPL were synthesized by the self‐assembly of HTzPTpy ligand with different cadmium halides (X=Cl, Br, and I). In the solid state, their LPL emission colors can be tuned by the time‐evolution, as well as excitation and temperature variation, realizing multi‐mode dynamic color tuning from green to yellow or green to red, and are the first such examples in single‐component coordination polymer materials. Single‐crystal X‐ray diffraction analysis and theoretical calculations reveal that the modification of LPL is due to the balanced action from single molecule and aggregate triplet excited states caused by an external heavy‐atom effect. The results show that the rational introduction of different halide anions into coordination polymers can realize multi‐color LPL.
By delicate design of coordination polymers incorporating different halogens, multi‐mode color‐tunable long persistent luminescence (LPL) from green to yellow or green to red was possible. The LPL emission colors can be tuned by time, excitation, and temperature, revealing the counter‐balanced mechanisms from single‐molecule and aggregate triplet excited states resulting from an external heavy‐atom effect.
The most daunting challenge of solid polymer electrolytes (SPEs) is the development of materials with simultaneously high ionic conductivity and mechanical strength. Herein, SPEs of lithium ...bis‐(trifluoromethanesulfonyl)imide (LiTFSI)‐doped poly(propylene monothiocarbonate)‐b‐poly(ethylene oxide) (PPMTC‐b‐PEO) block copolymers (BCPs) with both blocks associating with Li+ ions are prepared. It is found that the PPMTC‐b‐PEO/LiTFSI electrolytes with double conductive phases exhibit much higher ionic conductivity (2 × 10−4 S cm−1 at r.t.) than the BCP electrolytes with a single conductive phase. Concurrently, the storage moduli of PPMTCn‐b‐PEO44/LiTFSI electrolytes are ≈1–4 orders of magnitude higher than that of the neat PEO/LiTFSI electrolytes. Therefore, simultaneous improvement of ionic conductivity and mechanical properties is achieved by construction of a microphase‐separated and disordered structure with double conductive phases.
Solid polymer electrolytes (SPEs) of lithium bis‐(trifluoromethanesulfonyl)imide‐doped poly(propylene monothiocarbonate)‐b‐poly(ethylene oxide) block copolymers are successfully fabricated. SPEs with simultaneously improved ionic conductivity and storage moduli are achieved by construction of a microphase‐separated and disordered structure with double conductive phases, offering an effective strategy for the design of SPEs with optimized and balanced properties for advanced lithium battery technology.
The multiple metastable excited states provided by excited‐state intramolecular proton transfer (ESIPT) molecules are beneficial to bring temperature‐dependent and color‐tunable long persistent ...luminescence (LPL). Meanwhile, ESIPT molecules are intrinsically suitable to be modulated as D‐π‐A structure to obtain both one/two‐photon excitation and LPL emission simultaneously. Herein, we report the rational design of a dynamic CdII coordination polymer (LIFM‐106) from ESIPT ligand to achieve the above goals. By comparing LIFM‐106 with the counterparts, we established a temperature‐regulated competitive relationship between singlet excimer and triplet LPL emission. The optimization of ligand aggregation mode effectively boost the competitiveness of the latter. In result, LIFM‐106 shows outstanding one/two‐photon excited LPL performance with wide temperature range (100–380 K) and tunable color (green to red). The multichannel radiation process was further elucidated by transient absorption and theoretical calculations, benefiting for the application in anti‐counterfeiting systems.
One/two‐photon‐excited long persistent luminescence (LPL) was obtained in an ESIPT‐attributed CdII coordination polymer (LIFM‐106) with wide temperature range (100–380 K) and color tunability. Comparative study manifests the rational ligand modification and J‐aggregation in LIFM‐106 enhances the competitiveness of monomer LPL to counter‐balance the excimer emission.
Fascioliasis is a common parasitic disease in livestock in China. However, human fascioliasis is rarely reported in the country. Here we describe an outbreak of human fascioliasis in Yunnan province. ...We reviewed the complete clinical records of 29 patients and performed an epidemiological investigation on the general human population and animals in the outbreak locality. Our findings support an outbreak due to Fasciola gigantica with a peak in late November, 2011. The most common symptoms were remittent fever, epigastric tenderness, and hepatalgia. Eosinophilia and tunnel-like lesions in ultrasound imaging in the liver were also commonly seen. Significant improvement of patients' condition was achieved by administration of triclabendazole®. Fasciola spp. were discovered in local cattle (28.6%) and goats (26.0%). Molecular evidence showed a coexistence of F. gigantica and F. hepatica. However, all eggs seen in humans were confirmed to be F. gigantica. Herb (Houttuynia cordata) was most likely the source of infections. Our findings indicate that human fascioliasis is a neglected disease in China. The distribution of triclabendazole®, the only efficacious drug against human fascioliasis, should be promoted.
The strong adhesion of thermally conductive silicone encapsulants on highly integrated electronic devices can avoid external damages and lead to an improved long-term reliability, which is critical ...for their commercial application. However, due to their low surface energy and chemical reactivity, the self-adhesive ability of silicone encapsulants to substrates need to be explored further. Here, we developed epoxy and alkoxy groups-bifunctionalized tetramethylcyclotetrasiloxane (D4H-MSEP) and boron-modified polydimethylsiloxane (PDMS-B), which were synthesized and utilized as synergistic adhesion promoters to provide two-component addition-cured liquid silicone rubber (LSR) with a good self-adhesion ability for applications in electronic packaging at moderate temperatures. The chemical structures of D4H-MSEP and PDMS-B were characterized by Fourier transform infrared spectroscopy. The mass percentage of PDMS-B to D4H-MSEP, the adhesion promoters content and the curing temperature on the adhesion strength of LSR towards substrates were systematically investigated. In detail, the LSR with 2.0 wt% D4H-MSEP and 0.6 wt% PDMS-B exhibited a lap-shear strength of 1.12 MPa towards Al plates when curing at 80 °C, and the cohesive failure was also observed. The LSR presented a thermal conductivity of 1.59 W m−1 K−1 and good fluidity, which provided a sufficient heat dissipation ability and fluidity for potting applications with 85.7 wt% loading of spherical α-Al2O3. Importantly, 85 °C and 85% relative humidity durability testing demonstrated LSR with a good encapsulation capacity in long-term processes. This strategy endows LSR with a good self-adhesive ability at moderate temperatures, making it a promising material requiring long-term reliability in the encapsulation of temperature-sensitive electronic devices.
Metal–organic frameworks (MOFs) with long persistent luminescence (LPL) have attracted widespread attention due to potential applications in displays, anticounterfeiting, and so on. However, MOFs ...often have large pore size, which restricts the formation of efficient inter‐ and intramolecular interactions to realize LPL. Herein, a new approach to achieving LPL in MOFs by multifold interpenetration of discrete frameworks is reported. By comparison between threefold‐ and twofold‐interpenetrating MOFs, it was found that the former, which have higher multiplicity and denser frameworks, can be endowed with enhanced inter‐ and intramolecular interactions, and thus enhanced LPL is obtained. Meanwhile, metal‐cluster and heavy‐halogen effects could also cause variations in LPL duration and color.
Persistently luminescing: A new approach to achieving long persistent luminescence (LPL) in metal–organic frameworks (MOFs) by multifold interpenetration of discrete frameworks is reported. Comparison of threefold‐ and twofold‐interpenetrating MOFs revealed that the higher multiplicity and denser frameworks of the former can result in enhanced inter‐ and intramolecular interactions, and thus LPL is facilitated.
Pseudorabies virus (PRV) infection leads to severe inflammatory responses and tissue damage, and many natural herbs exhibit protective effects against viral infection by modulating the inflammatory ...response. An ethyl acetate fraction of flavonoids from Polygonum hydropiper L. (FEA) was prepared through ethanol extraction and ethyl acetate fractional extraction. An inflammatory model was established in RAW264.7 cells with PRV infection to evaluate the anti-inflammatory activity of FEA by measuring cell viability, nitric oxide (NO) production, reactive oxygen species (ROS) release, and mRNA expression of inflammatory factors, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Its functional mechanism was investigated by analyzing the phosphorylation and nuclear translocation of key proteins in the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Our findings indicate that PRV induced inflammatory responses in RAW264.7 cells, and the responses were similar to that in lipopolysaccharide (LPS)-stimulated cells. FEA significantly suppressed NO synthesis and down-regulated both expression and secretion of COX-2, iNOS, and inflammatory cytokines (P<0.05 or P<0.01). FEA also reduced NF-κB p65 translocation into the nucleus and decreased MAPK phosphorylation, indicating that the NF-κB/MAPK signaling pathway may be closely related to the inflammatory response during viral infection. The findings suggested the potential pharmaceutical application of FEA as a natural product that can treat viral infections due to its ability to mitigate inflammatory responses.
Abstract
Structural information for chemical compounds is often described by pictorial images in most scientific documents, which cannot be easily understood and manipulated by computers. This ...dilemma makes optical chemical structure recognition (OCSR) an essential tool for automatically mining knowledge from an enormous amount of literature. However, existing OCSR methods fall far short of our expectations for realistic requirements due to their poor recovery accuracy. In this paper, we developed a deep neural network model named ABC-Net (Atom and Bond Center Network) to predict graph structures directly. Based on the divide-and-conquer principle, we propose to model an atom or a bond as a single point in the center. In this way, we can leverage a fully convolutional neural network (CNN) to generate a series of heat-maps to identify these points and predict relevant properties, such as atom types, atom charges, bond types and other properties. Thus, the molecular structure can be recovered by assembling the detected atoms and bonds. Our approach integrates all the detection and property prediction tasks into a single fully CNN, which is scalable and capable of processing molecular images quite efficiently. Experimental results demonstrate that our method could achieve a significant improvement in recognition performance compared with publicly available tools. The proposed method could be considered as a promising solution to OCSR problems and a starting point for the acquisition of molecular information in the literature.
Accurate and efficient prediction of molecular properties is one of the fundamental issues in drug design and discovery pipelines. Traditional feature engineering-based approaches require extensive ...expertise in the feature design and selection process. With the development of artificial intelligence (AI) technologies, data-driven methods exhibit unparalleled advantages over the feature engineering-based methods in various domains. Nevertheless, when applied to molecular property prediction, AI models usually suffer from the scarcity of labeled data and show poor generalization ability.
In this study, we proposed molecular graph BERT (MG-BERT), which integrates the local message passing mechanism of graph neural networks (GNNs) into the powerful BERT model to facilitate learning from molecular graphs. Furthermore, an effective self-supervised learning strategy named masked atoms prediction was proposed to pretrain the MG-BERT model on a large amount of unlabeled data to mine context information in molecules. We found the MG-BERT model can generate context-sensitive atomic representations after pretraining and transfer the learned knowledge to the prediction of a variety of molecular properties. The experimental results show that the pretrained MG-BERT model with a little extra fine-tuning can consistently outperform the state-of-the-art methods on all 11 ADMET datasets. Moreover, the MG-BERT model leverages attention mechanisms to focus on atomic features essential to the target property, providing excellent interpretability for the trained model. The MG-BERT model does not require any hand-crafted feature as input and is more reliable due to its excellent interpretability, providing a novel framework to develop state-of-the-art models for a wide range of drug discovery tasks.
PDF
