Latest ArticlesIn the crystal engineering area, it is important to clearly demonstrating the relationship of structure and certain functionality. Herein, we present the study of the relationship of structure with phosphorescent nature for two new room temperature phosphorescence (RTP) coordination polymers (CPs). [Pb(FDA)(H2O)] (1) and [NH3(CH3)NH2(CH3)2][Pb4(FDA)5] (2), where H2FDA is 2, 5-furandicarboxylic acid, have been synthesized by solvothermal method using different solvents and Pb2+ sources and characterized by microanalysis, powder X-ray diffraction (PXRD), thermogravimetric (TG), IR and UV–vis spectra. The Pb2+ ions adopt bicapped triangle prism coordination sphere in 1 and 2, which are connected together via FDA2− ligands into bilayer structure in 1 while pillared-layer framework in 2. The FDA2− ligands show different bridging modes in 1 and 2, leading to distinct coordination interactions between Pb2+ ion and FDA2− ligand in both CPs. Both 1 and 2 emit ligand-centered RTP due to the heavy atom of Pb2+ ion, with a lifetime and quantum yield of 0.62 ms and 14.9% in 1 versus 1.69 ms and 15.7% in 2. The emission peak shows significant redshift (79 nm) in 2 regarding 1, which arises from their distinction of coordination interactions between Pb2+ ion and FDA2− ligand in both CPs.
Developing high-efficiency, inexpensive, and steady non-precious metal oxygen reduction reaction (ORR) catalysts to displace Pt-based catalysts is significant for commercial applications of Al-air battery. Here, we have prepared the Cu/Cu2O-NC catalyst with excellent ORR performance and high stability, due to the synergistic effect of Cu and Cu2O nanoparticles. The half-wave potential (0.8 V) and the limiting-current density (5.20 mA/cm2) of the Cu/Cu2O-NC are very close to those of the 20% Pt/C catalyst (0.82 V, 5.10 mA/cm2). Besides, it exhibits excellent performance with a maximal power density of 250 mW/cm2 and a stable continuous discharge for more than 90 h in the Al-air battery test. The promoting effects of Cu2O towards Cu-based ORR catalysts are illustrated as follows: (i) Cu2O is the major ORR active site by the redox of Cu(Ⅱ)/Cu(Ⅰ), which provides excellent ORR activities; (ii) Cu can stabilize the location of Cu2O by assisting the electron transfer to Cu(Ⅱ)/Cu(Ⅰ) redox, which is conducive to the high stability of the catalyst. This work provides a useful strategy for enhancing the ORR performance of Cu-based catalysts.
We herein report a new lanthanide metal-organic framework (MOF) that exhibits excellent chemical stability, especially in the aqueous solution over a wide pH range from 1 to 14. In contrast to many reported lanthanide MOFs, this Tb-based MOF emits cyan fluorescence inherited from the integrated AIE-active ligand, rather than Ln3+ ions. More remarkably, its fluorescence signal features a highly selective and sensitive "turn-off" response toward CrO42−, Cr2O72− and Fe3+ ions, highlighted with the low detection limits down to 68.18, 69.85 and 138.8 ppm, respectively. Thus, the exceptional structural stability and sensing performance render this material able to be a superior luminescent sensor for heavy metal ions in wastewater.
Living-cell imaging demands high specificity, sensitivity, and minimal background interference to the targets of interest. However, developing a desirable imaging probe that can possess all the above features is still challenging. The bioorthogonal surface-enhanced Raman scattering (SERS) imaging has been recently emerged through utilizing Raman reporters with characteristic peaks in Raman-silent region of cells (1800-2800 cm-1), which opens a revolutionary avenue for living-cell imaging with multiplexing capability. In this review, we focus on the recent advances in the technology development and the biological and biomedical applications of the living-cell bioorthogonal SERS imaging technique. After introduction of fundamental principles for bioorthogonal tag or label, we present applications for visualization of various intracellular components and environment including proteins, nucleic acids, lipids, pH and hypoxia, even for cancer diagnosis in tissue samples. Then, various bioorthogonal SERS imaging-guided therapy strategies have been discussed such as phototherapy and surgery. In conclusion, this strategy has great potential to be a flexible and robust tool for visualization detection and diseases diagnosis.
Sulfoxonium ylides as carbene precursors couple smoothly with thioureas in the presence of 5 mol% of rhodium(Ⅱ) acetate dimmer via carbenoid insertion to afford the corresponding 2-aminothiazoles with high chemoselectivity, providing a facile and efficient approach to access a variety of 2-aminothiazole derivatives with good functional groups tolerance.
Recently, the degradation of organic compounds in saline dye wastewater by sulfate radicals (SO4·-)-based advanced oxidation processes (AOPs) have attracted much attention. However, previous studies on these systems have selected non-chlorinated dyes as model compounds, and little is known about the transformation of chlorinated dyes in such systems. In this study, acid yellow 17 (AY-17) was selected as a model of chlorinated contaminants, and the degradation kinetics and evolution of oxidation byproducts were investigated in the UV/PDS system. AY-17 can be efficiently degraded (over 98% decolorization) under 90 min irradiation at pH 2.0–3.0, and the reaction follows pseudo-first order kinetics. Cl- accelerated the degradation of AY-17, but simultaneously led to an undesirable increase of absorbable organic halogen (AOX). Several chlorinated byproducts were identified by liquid chromatography-mass spectrometry (LC–MS/MS) in the UV/PDS system. It indicates that endogenic chlorine and exogenic Cl– reacted with SO4·- to form chloride radicals, which are involved in the dechlorination and rechlorination of AY-17 and intermediates. The possible degradation mechanisms of AY-17 photooxidative degradation are proposed. This work provides valuable information for further studies on the role of exogenic chloride in the degradation of chlorinated azo dyes and the kinetic parameters in the PDS-based oxidation process.
Lipid droplets (LDs) are intracellular lipid-metabolism organelles that involved in many physiological processes, metabolic disorders as well as diseases such as atherosclerosis. However, the specific probes that can visually locate abnormal LDs-rich tissues and track LDs-associated behavior to the naked eye with adequate biosafety still are rare. Herein, we develop a new design strategy of LDs-targeted probe based on the solvatochromism of coumarin derivatives. The results revealed that the emission wavelength of coumarin fluorophores gradually red shift in different solvents with increasing polarity, while absorption wavelength almost unchanged. As a result, the enlarged stokes shift of coumarin was emerged from oil to water. Furthermore, properly reducing water solubility and adding electronic donor at the structure of coumarins can enlarge this type of solvatochromism. This discovery was utilized to develop suitable probe for the image of LDs and LDs-rich tissues with high resolution and biosafety. Therefore, LDs-associated behavior was visible to the naked eye during the process of lipophagy and atherosclerosis. We deem that the developed probe here offers a new possibility to accurately diagnosis and analyse LDs-related diseases in clinic and preclinical study.
Here we propose a fluorescent sensor, Chroma-V, consisted of a Hoechst ligand (Hoe) to target chromatin DNA and a BODIPY rotor (BDP) to sense the local viscosity that reflects chromatin condensation state. Within Chroma-V, efficient FRET process from Hoe to BDP facilitated a single-excitation ratiometric imaging of nucleus DNA under fluorescence confocal microscope, which utilized the ratio of two channels to enable an intuitive visualization of chromatin condensation state. And fluorescence lifetime imaging (FLIM) based on fluorescent signal from BDP proved to be a more accurate method to quantify the changes of chromatin condensation state under different epigenetic states, including histone acetylation regulated by deacetylase inhibitors, cell apoptosis induced by DNA-bining drugs, and the epithelial-mesenchymal transition of HUVEC cells induced by TGF-β.
Semiconductor-mediated photocatalysis is a promising photochemical process for harvesting inexhaustible solar energy to address the energy crisis and environmental issues. However, the low solar-light response and poor carrier migration are severe drawbacks that limit its practical application. Herein, we propose a convenient pathway for improving electron-hole separation and solar energy utilisation by engineering defective ZnIn2S4 with doping of carbon dots. The optimum ZnIn2S4/CD200 nanosheet exhibited 100% diclofenac (DCF) degradation within 12 min under visible-light. The estimated photocatalytic efficiency under natural sunlight was 98.2%. Scavenging experiments and electron spin resonance (ESR) analysis indicated that the superoxide radical (O2∙−), photoelectron (e−), hole (h+) and hydroxyl radical (∙OH) were the predominant contributions in the ZnIn2S4/CD200/DCF/visible light system. Furthermore, ZnIn2S4/CD200 exhibited excellent reusability and stability after 4 times recycling. The photodegradation routes mainly involved hydroxylation, decarboxylation, CN bond cleavage, dechlorination, ring closure, and ring-opening. The ecological risk assessment and total organic carbon (TOC) tests exhibited desirable toxicity reduction and mineralization results. These observations not only offer a facile strategy for the construction of defective ZnIn2S4, but also pioneer the direct utilisation of natural light for highly efficient environmental remediation.
Owing to excellent light absorption and high activity for oxygen evolution, monoclinic bismuth vanadate (BiVO4) is regarded as an ideal candidate for photocatalytic water splitting. However, its application is limited by the large particle size in micrometer scale, as well as the slightly positive conduction band. In this work, we successfully synthesized nano-BiVO4 with particle size ranged from 27 nm to 57 nm by wet chemical method based on electrostatic spinning method. Unlike bulk BiVO4, the nano-sized BiVO4 possesses the ability to generate hydrogen by water splitting, and the activity could reach up to 1.66 μmol h−1g−1 with the assistance of Pt. The enhanced activity is mainly attributed to the improvements resulted from reduced particle size, which includes elevated conduction band, enlarged specific surface area and promoted charge separation. This work provides a simple method for synthesizing photocatalyst with small particle size and high yield.
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