Latest ArticlesThis work detailed the preparation of a class of water-soluble PNP ligands that differed by the nature of the substitute on phenyl ring of ligands. These ligands were incorporated into water-soluble rhodium-PNP complex catalysts that were used to regioselective hydroformylation of a series of terminal arylalkenes, providing efficient access to rac-α-aryl propionaldehydes in good to excellent yield (up to 97%) and branched-regioselectivity (up to 40:1 b/l ratio). Furthermore, gram-scale and diverse synthetic transformation demonstrated synthetic application of this methodology for non-steroidal antiinflammatory drugs.
The synthesis of cyclic polymer is an important topic in polymer chemistry. Herein, we report a one-step method to prepare cyclic polypyrazoles. Monomers with two functional groups, diazo and alkyne, were synthesized and polymerized via 1,3-diploar cycloaddition in bulk under heating without any catalyst. Polypyrazoles with molecular weights in the range of 3800-4400 g/mol and yields in the range of 78.8-98.7% were successfully synthesized. No chain end group was detected by LC-QTOF-MS and FTIR, which proves the cyclic structure of polypyrazoles. What is noteworthy is that the cyclic polypyrazoles can self-assemble into vesicles during the reprecipitation process, which was proved by the results of SEM and TEM. The reason for that is the formation of intermolecular hydrogen bond between NH and ester groups.
Here, a rhodium(Ⅲ)-catalyzed benzo[c]azepine-1, 3(2H)-dione synthesis via tandem C–H alkylation and intramolecular amination of N-methoxylbenzamide with 3-bromo-3, 3-difluoropropene as the alkylation agent is reported. The substituted benzamides and protected indoles are all tolerated, yielding the corresponding products in moderate to good yields. Further study revealed those bioactive compounds such as piperic acid and a key precursor of Roflumilast all perform well, highlighting the synthetic utility of this method.
We report supramolecular AND logic gates based on host-guest complexation between acid-labile acyclic cucurbit[n]uril (CB[n]) molecular container and NaClO-responsive dye. Supramolecular AND logic gate is turned on due to acid-triggered degradation of molecular container and the release of the dye, followed by NaClO-induced fluorescence "switch on" effect of the dye. The reason for AND molecular logic gate is discovered to be the combination of oxidation inhibition and fluorescence "switch off" effect. Supramolecular AND logic gate is confirmed to be operational in live MCF-7 and HeLa cancer cells.
To address the challenge of treating complex pollutants containing heavy metals and organic compounds, a phenanthroline/TiO2 nanocomposite with rich oxygen vacancy defects was synthesized to integrate the functions of pollutant detection, adsorption, and photocatalytic degradation. The results showed that the nanocomposite could adsorb Cr3+ and the process could be transduced into a colorimetric signal for qualitative and quantitative detection. The adsorbed heavy metal also exhibited a synergistically enhanced photocatalytic degradation of a model organic pollutant under visible light. The simultaneous adsorption, detection, and photocatalysis could reduce the multifarious operations and high cost of traditional environmental remediation methods, indicating a strong application potential for the nanocomposite.
Three bench-stable difluoromethylene phosphonate hydrazones were prepared from simple diethyl(difluoromethyl)phosphonate within two steps in good yields. The [3 + 2] cycloaddition reaction of these diazo precursors with aryl diazonium salts has been accomplished under metal-free conditions with exclusive regioselectivity. This transformation provides practical access to a broad panel of 2-aryl-2H-tetrazol-5-yl difluoromethylene phosphonates, including the corresponding derivatives of amino acid (phenylalanine) and drug cores (Pomalidomide and Lapatinib fragment).
We demonstrate hole-transport-layer-free light-emitting diodes (LEDs) based on solution-processed multiple-quantum-well (MQW) perovskite. The MQW perovskite can self-assemble to a unique structure of vertically graded distribution with two-dimensional layered perovskite covered by three-dimensional-like perovskite at top, which can naturally form a barrier of electron transporting to the anode interface, thereby enhancing the charge capture efficiency. This leads to hole-transport-layer-free MQW perovskite LEDs reaching an external quantum efficiency (EQE) of 9.0% with emission peak at 528 nm, which is over 6 times of LEDs based on three-dimensional perovskite with the same device structure, representing the record EQE of hole-transport-layer-free perovskite LED.
A phosphorescent supramolecular foldamer is conveniently constructed by the 1:1 host–guest complexation with cucurbit[8]uril and 1, 2-diaminocyclohexane-bridged 4-(4-bromophenyl)-pyridinium salt. The tightly compact host–guest complexation in molecular foldamer can greatly suppress the fluorescence emissive channel and promote the intersystem crossing from singlet to triplet states, thus leading to the green phosphorescence at ambient temperature in aqueous solution. More intriguingly, the phosphorescence emission shows very rapid and sensitive responsiveness to different antibiotics in both inanimate milieu and living cells. Remarkably, the limit of detection of such binary inclusion complex toward sulfamethazine can reach as low as 1.86 × 10−7 mol/L. Thus, it is envisaged that this supramolecular nanoplatform featuring unique complexation-enhanced phosphorescence emission may hold great promise in sensing and detecting many other biological targets under physiological environment.
Developing non-noble-metal oxygen evolution reaction (OER) electrocatalysts with high performance is critical to electrocatalytic water splitting. In this work, we fabricated CoFe-layered double hydroxide (LDH) nanowire arrays on graphite felt (CoFe-LDH/GF) via a hydrothermal method. The CoFe-LDH/GF, as a robust integrated 3D OER anode, exhibits excellent catalytic activity with the need of low overpotential of 252 and 285 mV to drive current densities of 10 and 100 mA/cm2 in 1.0 mol/L KOH, respectively. In addition, it also maintains electrochemical durability for at least 24 h. This work would open up avenues for the development of GF like attractive catalyst supports for oxygen evolution applications.
Lithium metal is deemed as an ideal anode material in lithium-ion batteries because of its ultrahigh theoretical specific capacity and the lowest redox potential. However, the rapid capacity attenuation and inferior security resulting from the dendritic lithium growth severely limit its commercialization. Herein a novel hybrid gel polymer electrolyte (GPE) based on electrospun lithium sulfonated polyoxadiazole (Li-SPOD) nanofibrous membrane swelled by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) ether liquid electrolyte is proposed to address the issue of lithium dendrites. The Li-SPOD membrane synthesized by a simple one-pot method exhibits excellent mechanical strength and thermal resistance due to its high molecular weight and rigid backbone. The electron-withdrawing oxadiazole ring and oxadiazole ring-Li+ complex, and N, O heteroatoms with lone pairs of electrons in Li-SPOD macromolecular chains facilitate the dissociation of -SO3Li group and Li+ transference. The hybrid Li-SPOD GPE exhibits both a high lithium-ion transference number (0.64) and high ionic conductivity (2.03 mS/cm) as well as superior interfacial compacity with lithium anodes. The LiFePO4-Li cell using this novel GPE can operate steadily at 2 C for 300 cycles, remaining a high discharge capacity of 125 mAh/g and dendrite-free anode. Remarkable performance improvements for the Li-Li and Cu-Li cells are also presented.