Latest ArticlesIn the physiological environment, nanoparticles (NPs) interact with proteins to form a protein-rich layer on the surface which is called "protein corona". Understanding and analyzing the formation process of protein corona and protein corona-nanoparticles is of great significance for biological related nano research. Many separation techniques have been used to analyze the composition of protein corona, but in situ analysis of protein corona is still absent. With the development of detection technology, sum frequency generation (SFG) is an effective instrument to analyze the surface protein structure and dynamic changes of protein corona in situ. In this work the molecular mechanism and surface structure effect of the interaction between nanoparticles with surface protein corona (S-NPP) and phospholipid membrane were studied. When S-NPP interacts with phospholipid membrane, the bond affinity network formed by the binding water can stabilize S-NPP around the lipid bilayer. In this process, S-NPP can be found wrapped in the hydration shell. This ultimately leads to a more moderate interaction between particles and phospholipid membrane.
Electrochemical nitrogen reduction reaction (ENRR) provides a promising strategy to achieve sustainable synthesis of ammonia. However, despite great efforts devoted to this research field, the problems such as low energy efficiency and weak selectivity still impede its practical implementation. Most of the research to date has been concentrated on creating sophisticated electrocatalysts, and adequate knowledge of electrolytes is still lacking. Herein, the recent progress in electrolytes for ENRR, including alkaline, neutral, acidic, water-in-salt, organic, ionic liquid, and mixed water-organic electrolytes, is thoroughly reviewed to obtain an in-depth understanding of their effects on electrocatalytic performance. Recently developed representative electrocatalysts in various types of electrolytes are also introduced, and future research priorities of different electrolytes are proposed to develop new and efficient ENRR systems.
MOF-based core-shell structures with high surface area, abundant active sites, and broad absorption bands are viable alternatives to traditional single-component photocatalysts. In this report, we describe the design and construction of delicate Ag nanowires@NH2-UiO-66 with a core-shell structure for use as photocatalysts in imine synthesis under light. The optimized composites exhibited 80% imine production, which was higher than both MOF and Ag NWs. The significant improvement in photocatalytic activity under light may be attributed to the plasmonic effect of silver nanowires and their core-shell structure, which promotes the separation of electron-hole pairs. Moreover, the photocatalytic activity of the core-shell nanostructure may provide valuable insight into the design and construction of MOF-based composite photocatalysts for oxidative coupling of amines.
Due to the high electrophilic nature of azo-dienophiles, azo-Diels–Alder proceeds rapidly even without the need of a catalyst and is therefore regarded as the "click reaction". This spontaneity causes strong background reaction and poses a daunting challenge to chemists for developing the catalytic asymmetric version. Reported herein is the first catalytic asymmetric dearomative azo-Diels–Alder reaction between 2-vinylindoles and triazoledione. This protocol makes use of the high energy barrier of dearomatization to avert the strong background reaction of azo-Diels–Alder reaction, allowing the implementation of the projected reaction at ambient temperature. Density functional theory calculations have been performed to gain insights into the reaction mechanism and the origins of the enantioselectivity. By using this method, a variety of tetracyclic indole derivatives have been readily prepared in good to excellent yields and with excellent diastereo- and enantio-selectivities (33 examples, up to 97% yield and > 99% ee, > 20:1 dr).
Spectroscopic investigations discovered that the in-situ generated phenylhydrazone anion was significantly bathochromically shifted to visible light region for photoactivation under irradiation. The photoexcited phenylhydrazone anion was potential to reduce aryl iodides via single electron transfer process for the subsequent radical chain reaction. A redox-neutral photochemical carbonylation of aryl iodides was developed on basis of the special spectroscopic features of phenylhydrazone anion. This protocol provided a convenient and efficient synthetic tool for accessing carbonylation products under redox neutral conditions without the need of transition-metals.
Supported Pd based catalysts are considered as the efficient candidates for low-carbon alkane oxidation for their outstanding capability to break C-H bond. Whereas, the irreversible deactivation of Pd based catalysts was still frequently observed. Herein, we reinforced the extruded Pd nanoparticles with quantitive Pt to assemble the evenly distributed PdPt nanoalloy onto ferrite perovskite (PdPt-LCF) matrix with strengthened robustness of metal/oxide support interface. We further co-achieved the enhanced performance, anti-overoxidation as well as resistance of vapor-poisoning in durability measurement. The operando X-ray photoelectron spectroscopy (O-XPS) combined with various morphology characterizations confirms that the accumulation of surface deep-oxidation species of Pd4+ is the culprit for fast activity loss in exsolved Pd system, especially at high temperature of 400 ℃. Conversely, it could be completely suppressed by in-situ alloying Pd with equal amount of Pt, which helps maintain the metastable Pd2+/Pd shell and metallic solid-solution core structure. The density function theory (DFT) calculations further buttress that the dissociation of CH was facilitated on alloy/perovskite interface which is, on the contrary, resistant toward O–H bond cleavage, as compared to Pd/perovskite. Our work suggests that the modification of exsolved metal/oxide catalytic interface could further enrich the toolkit of heterogeneous catalyst design.
Lidocaine hydrochloride (LIDH) as an anesthetic is widely used in local anesthesia. Dissolving microneedles (MNs) have great application value in the field of skin anesthesia. However, the limited drug-loading of dissolving MNs is an existing challenge that affects clinical use. In this study, we have screened isomaltulose (ISO) as the proper matrix material for the MNs by using molecular dynamics (MD) simulation. Our findings indicate that ISO has good compatibility with LIDH, and the LIDH-loaded ISO MNs (LI-MNs) have high drug-loading capacity. The drug-loading capacity of LI-MNs could reach 80%, and it could effectively puncture the skin. In addition, the preparation method of customized LI-MNs was established based on three-dimensional (3D) printing technology. It was shown that the administration time of LI-MNs could be controlled within 3 min. Also, the LI-MNs were able to provide the local anesthetic efficacy within 2 min and sustained for more than 2 h. Significantly, LI-MNs had more efficient drug efficacy compared to the topical creams and the majority of existing LIDH-loaded dissolving MNs. They even provided a longer duration of action than the injections. Overall, the LI-MNs with high drug-loading have a promising application prospect.
Tin-based chalcogenides have attracted tremendous attention as an anode material for sodium storage owing to their unique structure and high theoretical capacity. Unfortunately, the large volume change and poor conductivity lead to sluggish reaction kinetics and poor cycling performance. Herein, SnS0.5Se0.5 nanoparticles coupled with N/S/Se triple-doped carbon nanofibers (SnS0.5Se0.5@NSSe-C) are designed and synthesized through electrospinning and annealing process. Benefiting from the synergistic effects of SnS0.5Se0.5 and NSSe-C, the SnS0.5Se0.5@NSSe-C nanofibers exhibit a high reversible capacity and ultralong cycle life at higher current density for sodium-ion batteries. Furthermore, the sodium storage mechanism and electrochemical reaction kinetics of the SnS0.5Se0.5@NSSe-C composite are characterized by the in-situ measurements. The theoretical calculations further reveal the structural advantages of SnS0.5Se0.5@NSSe-C composite, which exhibits a high adsorption energy of Na+. This work can provide a novel idea for the synthesis of ternary tin-based chalcogenides and is beneficial for the investigation of their reaction kinetics.
Microplasma based on glow discharge could act as a non-contact gaseous electrode and has attracted much attention in both fundamental research and application. Herein, with microplasma as the anode, the electrodeposition process of a series of metal and metal alloys in molten salt has been systemically studied. Four metal cations with different valence states, silver (Ag+), nickel (Ni2+), copper (Cu2+), and iron (Fe3+), could all be reduced on the solid cathode with high current efficiency and the corresponding metal products were of high purity. The electrodeposition of aluminum-lanthanum (Al-Ln) alloy on the aluminum cathode was also successfully carried out with microplasma as the anode, and the same alloy was obtained by using the conventional anode electrode. These results indicated that microplasma anode based on non-contact direct-current (DC) glow discharge is a promising electrode to be applied in molten salt electrolysis.
Inverse vulcanized polymers (IVPs) that generated from elemental sulfur and smaller amounts of alkenes have found broad promising applications such as cathode materials for Li-S batteries, dynamic and repairable materials, optics applications, and metal sorption. However, their exploration in organic synthesis is still unprecedented. Here we first report the application of inverse vulcanized polymers in catalysis for organic transformations. A biomass-derived inverse vulcanized polymer (IVP-EAE) is found to be capable of catalyzing cross-coupling reactions in a transition-metal-free fashion under visible light. This method allows the direct CH functionalization of pyrroles and N-arylacrylamides with (hetero)aryl halides, respectively, leading to the formation of two sets of structurally important scaffolds including pyrrole-containing biaryls and 3,3′-disubstituted oxindoles with high selectivity. We anticipate this study will not only unveil the new potential of IVPs, but also offer a distinct type of catalysts for organic transformations.