Latest ArticlesThe new reactions between o-hydroxyphenyl enaminones and Langlois reagent (CF3SO2Na) for the tunable synthesis of 3-(trifluoromethylthio) chromones and 3-trifluoromethylsulfinyl chromones are reported herein. Both type of reactions proceed under transition metal-free conditions. In addition, the conditions for the synthesis of 3-trifluoromethylsulfinyl chromones have also been found to be applicable for the synthesis of 3-alkyl/arylsulfinyl chromones.
Gas adsorption remains an attractive area of research. The hierarchical structure can reduce diffusion limitations and facilitate molecular transport, while acid sites can be used as adsorption sites. These make zeolites widely used in the field of gas adsorption. How to obtain zeolite adsorbents with better adsorption properties by modulating the hierarchical structure and acid sites is a pressing issue nowadays. This review highlights the strategies to modulate the hierarchical structure as well as the acid sites; and then explains how these strategies are achieved. The mechanism of zeolite adsorption on gases is then described in terms of these two properties. Lastly, the adsorption properties of zeolites for certain gases under specific conditions are summarised. An outlook of zeolite hierarchical structures and acid site modulation strategies is given.
In the exploration of circularly polarized luminescence (CPL) materials, doping cholesteric liquid crystals (CLCs) with achiral dyes is a common strategy. Conjugated polymers are favored as achiral dyes for their superior luminescent properties. In this study, a series of oligomers (M1-M3) and the conjugated polymer F8BT were synthesized to systematically assess the impact of the length of the conjugated backbone on CPL signals of CLCs doped with conjugated polymers. As the length rose from M1 to M3, CPL intensity concurrently increased (glum increased from 0.35 to 0.84), attributable to enhanced dichroism (order parameter, SF increased from 0.20 to 0.56). In contrast, F8BT polymer resulted in diminished CPL intensity (|glum| = 0.64) due to the reduced compatibility. Achieving a balance between dichroism and compatibility is crucial for optimizing CPL in conjugated polymer-doped CLCs. The guiding principle established here may have broad applicability in other CPL assemblies, offering a strategic avenue to engineer high-performance CPL materials with conjugated polymer.
Efficient activation of molecular oxygen (O2) is considered a promising technique for the removal of antibiotics. However, how to effectively regulate electrons distribution to promote O2 activation remains a challenge at present. In this study, phosphorus and sodium co-doped carbon nitride (PNaCN) were designed to rearrange the electrons distribution to activate O2 for the degradation of tetracycline. The generation of •O2−was innovatively observed via in-situ O2 fitting Fourier transform infrared (FTIR) spectroscopy, demonstrating the outstanding O2 activation ability of PNa5. Density functional theory (DFT) further confirmed that the rational co-doping led to the rearrangement of local electrons, resulting in electron-rich Na sites and electron-deficient P sites. These sites exhibited greater susceptibility to O2 adsorption and charge transfer. Besides, the degradation rate of tetracycline was increased by 2.44 times using co-doped CN. This study provides a new inspiration for enhancing O2 activation by inducing electrons rearrangement.
Benzo[4,5]imidazo[1,2-a]pyrimidine-based derivatives play crucial roles in medicines, pesticides, tracers and photoelectric materials. However, their synthesis approach still needs to be optimized, and their fluorescent properties in intracellular microenvironment are unclear. Here, a Cu(Ⅱ)-catalyzed cascade coupling cyclization reaction was successfully developed to synthesize benzo[4,5]imidazo[1,2-a]pyrimidine scaffold with mild reaction conditions, broad substrate scopes and high yields. After a system study, we found that compound 4aa displayed an optimal viscosity-specific response with remarkable fluorescence enhancement (102-fold) for glycerol at 490 nm. Particularly, 4aa possessed excellent structure-inherent targeting (SIT) capability for lysosome (P = 0.95) with high pH stability and large Stokes shift. Importantly, 4aa was validated for its effectiveness in diagnosing lysosomal storage disorders (LSD) in living cells. The 4aa also showed its potential to map the micro-viscosity and its metabolism process in zebrafish. This work not only affords an efficient protocol to fabricate benzo[4,5]imidazo[1,2-a]pyrimidine derivatives, reveals this skeleton has excellent SIT features for lysosome, but also manifests that 4aa can serve as a practical tool to monitor lysosomal viscosity and diagnose LSD.
Nanographenes (NGs) with twisted backbones are emerging as new candidates for chiroptical materials. In this work, we describe a new strategy for synthesizing a [10]twistacene-embedded NG which exhibits a rare flag-hinge-like geometry. By neatly creating steric crowding on the [6]helicene breaches of the NG skeleton, the synthesis only provided homochiral isomers without generating the "meso‑" isomer. The formed NGs showed high luminescence with quantum yield up to 52%, and promising circularly polarized luminescence (CPL) performance with |glum| up to 5.0 × 10−3. Besides, these NGs also showed outstanding CPL brightness (BCPL) up to 305 L mol−1 cm−1 among chiral NGs.
The supramolecular Förster resonance energy transfer (FRET) is seen as a promising approach for organic photocatalysis using dyes as catalysts, because it combines the high efficiency of energy transfer with the dynamic responsiveness based on non-covalent interactions. Here we propose a supramolecular FRET photocatalysis strategy for α-oxyamination reaction based on supramolecular confinement effect. The well-designed benzothiadiazole-based cationic monomer as energy donor and the dyes of Nile Red as acceptor are doped into the amphiphilic surfactants of sodium dodecyl sulfate (SDS). Benefitting from the supramolecular confinement space provided by SDS in aqueous environment, the FRET process between the monomer and Nile Red is effectively achieved (exciton migration rate: 3.99 × 1014 L mol‒1 s‒1). On this basis, the supramolecular FRET system is used as an efficient energy source to catalyze α-oxyamination reactions between a series of 1,3-dicarbonyl compounds and 2,2,6,6-tetramethylpiperidine-1-oxyl under white LED light, showing a yield as high as 94% and a turnover frequency value of 3.92 h‒1. This photocatalytic result shows a great enhancement compared to that of Nile Red alone.
Highly active transition metal nitrides are desirable for electrocatalytic reactions, but their long-term stability is still unsatisfactory and thus limiting commercial applications. Herein, for the first time, we report a unique and universal room-temperature urea plasma method for controllable synthesis of N-doped carbon coated metal (Fe, Co, Ni, etc.) nitrides arrays electrocatalysts. The preformed metal oxides arrays can be successfully converted into metal nitrides arrays with preserved nanostructures and a thin layer of N-doped carbon (N-C) via one-step urea plasma. Typically, as a representative case, N-C@CoN nanowire arrays are illustrated and corresponding formation mechanism by plasma is proposed. Notably, the designed N-C@CoN catalysts deliver excellent electrocatalytic activity and long-term stability both in oxygen evolution reaction (OER) and urea oxidation reaction (UOR). For OER, a low overpotential (264 mV at 10 mA/cm2) and high stability (>50 h at 20 mA/cm2) are acquired. For UOR, a current density of 100 mA/cm2 is achieved at only 1.39 V and maintain over 100 h. Theoretical calculations reveal that the synergetic coupling effect of CoN and N-C can significantly facilitate the charge-transfer process, optimize adsorbed intermediates binding strength and further greatly decrease the energy barrier. This strategy provides a novel method for fabrication of N-C@ metal nitrides as highly active and stable catalysts.