Latest ArticlesDeveloping efficient and long wavelength sensitive unimolecular photoinitiators (PIs) is still facing a great challenge. In this work, a series of thioxanthone-based N-hydroxyphthalimide esters (TX-NHPIEs) were synthesized by installing NHPIEs along the TX backbone and characterized. The investigated TX-NHPIEs have a 60 nm redshift and demonstrate sterling initiating efficiency for free radical photopolymerization (FRP) under LED@450 nm light irradiation compared with the commercialized isopropylthioxanthone (ITX). Real-time 1Hnuclear magnetic resonance (1H NMR), electron spin resonance (ESR), decarboxylation and gas chromatograph-mass spectrometer (GC–MS) experiments and density functional theory (DFT) reveal that TX-NHPIEs can generate one alkyl radical and one N-centered iminyl radical, which can initiate FRP directly and indirectly, respectively. In other words, TX-NHPIEs absorb one photon and can generate two active radicals, which break through the limitations of common PIs. TX-NHPIE-Cpe demonstrates the highest initiating efficiency, and its application in coatings and 3D printing was also studied, indicating TX-NHPIEs have broad potential applications in photopolymerization processes.
Formic acid (FA), which is obtainable through CO2 hydrogenation with green hydrogen or biomass conversion, has been used as a prospective liquid organic hydrogen carrier (LOHC) because of the abundant advantages of renewability, wide availability, stability, and high volumetric capacity (53 g H2/L). The development of highly efficient catalytic systems to achieve enhanced catalytic activity is attractive but still challenging. Herein, ultrafine and highly dispersed PdAu nanoclusters (NCs) anchored on amino-modified reduced graphene oxide (ArGO) were successfully synthesized via a facile impregnation-reduction method and applied as a catalyst toward formic acid dehydrogenation (FAD). Benefiting from the promoting effect of amino groups, the strain and ligand effect in the alloy, and the Mott–Schottky effect between PdAu NCs and ArGO, the resultant PdAu/ArGO affords an ultrahigh activity under visible light irradiation with an exceptional turnover frequency value of 10, 699.5 h−1 at 298 K without any additives, more than 2.6 times improvement than that under dark, which is the highest among all reported catalysts under the same conditions. This study provides a green and convenient strategy for developing more efficient and sustainable FAD catalysts and promotes the effective utilization of FA as a prospective renewable LOHC.
COVID-19 is a major event with worldwide influences. Since the beginning of the epidemic, pharmaceutical chemists have paid attention to the therapeutic effect of a variety of small molecule medicines on COVID-19 infection. A series of organic molecules are designed and found to be effective in the treatment of COVID-19 infection. In fact, no matter how effective they are, with the development of the COVID-19 epidemic, various small molecule medicines are gradually recognized by people. This is equivalent to a good science popularization of pharmaceutical chemistry. This review aims to introduce the molecules for COVID-19 treatment on the basis of their chemical structures, synthetic methods as well as their effects.
The utilization of an efficient photocatalyst is crucial for the photocatalytic degradation of antibiotics in water through visible light, which is an imperative requirement for the remediation of water environments. In this study, a novel Cu-CeO2/BiOBr Z-type heterojunction was synthesized by calcination and hydrothermal methods, and the degradation rate of sulfathiazole (STZ) antibiotic solution was studied using simulated illumination (300 W xenon lamp). The results indicated that 3% Cu-CeO2/BiOBr achieved a degradation rate of 92.3% within 90 min when treating 20 mg/L STZ solution, demonstrating its potential for practical water treatment applications. Characterization using various chemical instruments revealed that 3% Cu-CeO2/BiOBr exhibited the lowest electron-hole recombination rate and electron transfer resistance. Furthermore, the utilization of ESR data and quenching experiments has substantiated the involvement of hydroxyl radicals (•OH) and superoxide radicals (•O2−) as the primary active species. Consequently, a plausible degradation mechanism has been inferred. These findings offer a prospective approach for the development of heterojunction materials with appropriate band matching.
The external stimulus response strategy has been evolved rapidly in the field of olefin polymerization. In this work, we modularly synthesized three types of double stimulus responsive α-diimine palladium catalysts, combining redox regulation and other regulation together, such as light, Lewis acid and alkali cations. The catalytic activities and the molecular weight of polyethylene products can be regulated for 4 times in ethylene polymerization. These palladium complexes were also used for the copolymerization reaction of ethylene and polar monomers, such as methyl 10-undecylenate and methyl acrylate, effectively regulating the catalytic activities, the molecular weight and polar monomer incorporation of the prepared copolymers. The research on these dual-regulated palladium complexes makes full use of prepared catalysts and provides new inspirations for regulating olefin polymerization.
Dynamic DNA nanotechnology plays a significant role in nanomedicine and information science due to its high programmability based on Watson-Crick base pairing and nanoscale dimensions. Intelligent DNA machines and networks have been widely used in various fields, including molecular imaging, biosensors, drug delivery, information processing, and logic operations. Encoders serve as crucial components for information compilation and transfer, allowing the conversion of information from diverse application scenarios into a format recognized and applied by DNA circuits. However, there are only a few encoder designs with DNA outputs. Moreover, the molecular priority encoder is hardly designed. In this study, we introduce allosteric DNAzyme-based encoders for information transfer. The design of the allosteric domain and the recognition arm allows the input and output to be independent of each other and freely programmable. The pre-packaged mode design achieves uniformity of baseline dynamics and dynamics controllability. We also integrated non-nucleic acid molecules into the encoder through the aptamer design of the allosteric domain. Furthermore, we developed the 2-n encoder and the Endo Ⅳ-assisted priority encoder inspired by immunoglobulin's molecular structure and effector patterns. To our knowledge, the proposed encoder is the first enzyme-free DNA encoder with DNA output, and the priority encoder is the first molecular priority encoder in the DNA reaction network. Our encoders avoid complex operations on a single molecule, and their simple structure facilitates their application in complex DNA circuits and biological scenarios.
A nonsymmetrical PNN pincer ligand [6-(Bu2PNH)C5H4N-2-(3-Mes)C3H2N2] and its corresponding cobalt-N2 complex were synthesized and characterized. By the stoichiometric reaction of the PNN ligand lithium salt with CoCl2, the complex 3, (PNN)CoCl, was obtained. Then, reduction of 3 with NaBHEt3 under a dinitrogen atmosphere yielded complex 5, (PNN)Co(Ⅰ)(η1-N2). Single-crystal X-ray analysis, IR spectrum, and DFT calculations revealed that the dinitrogen in 5 was only weakly reduced by the cobalt center. The reactions of 5 with carbon monoxide and 2, 6-dimethylphenyl isocyanide gave carbonyl and isocyanide complexes 6 and 7 with the release of N2, respectively. Furthermore, these cobalt complexes, especially complex 5, demonstrated the capacity to convert dinitrogen to N(TMS)3 with moderate efficiency.
Utilizing CO2 for the production of bulky and valuable chemicals presents an attractive solution to address environmental and fossil energy crises. Among the various approaches, direct carboxylation of alcohols with CO2 stands out as an eco-friendly process capable of efficiently producing carboxylic acids in a sustainable manner. However, the high dissociation energy of the C-O bond poses a significant challenge in this process. Over the past few decades, several strategies have been developed to activate alcohols and establish efficient catalytic systems for carboxylation with CO2. Nevertheless, the sporadic nature of reported approaches makes it difficult to determine the most effective one. This perspective aims to provide an overview of the current state-of-the-art catalytic protocols for carboxylating alcohols with CO2, encompassing esterification, halogenation, and photocatalysis, while considering their respective advantages and limitations. We aim to discern the most promising avenues for future development in this field. The insights presented in this perspective will contribute to the advancement of efficient and sustainable carboxylation methods using CO2, leading to the production of valuable chemicals in future.
Metal-organic frameworks (MOFs) combined with specific ligands are highly adaptable smart materials that can respond to external and physiological stimuli. In this study, we introduced a pyridinyl zwitterionic ligand with light/pH dual response into magnetic MOF composite (Fe3O4@ZW-MOF) for enrichment of phosphorylated peptides for the first time. The introduction of the developed ligand gives MOF material dual response properties. Light stimulation affects the generation/disappearance of free radicals of the pyridine derivative, resulting in a change in the charge gradient of the zwitterion, and zwitterion can also regulate the pH of the solution by adding acid or base. Therefore, the reversible capture and release of phosphorylated peptides can be easily achieved by adjusting light and pH. The established phosphorylated peptide enrichment platform exhibits high sensitivity (detection limit of 1 fmol), high selectivity (β-casein: BSA, 1:1000), and good reusability (7 cycles). In addition, the method was applied to the enrichment of phosphorylated peptides in complex systems (non-fat milk and human serum), demonstrating the feasibility of this method for phosphoproteom analysis. In conclusion, the synthesized Fe3O4@ZW-MOF is a promising MOF material, which provides the possibility to advance the application of responsive MOFs materials in proteomics.
A highly efficient and concise bromocyclization has been successfully achieved, in which tryptamine/tryptophol derivates can be transformed to valuable HPI/TFI scaffolds with economic and green manners. Moreover, a controllable cascade transformation of bromocyclization and aromatic bromination has also been smoothly achieved to form dibrominated HPIs and TFIs. Production could be successfully scaled up under both the batch process and a continuous flow fashion. The most remarkable peculiarity of our process over all previous methods is that the generated water is the major waste. Notably, successful application of this new protocol has been demonstrated by the pharmaceutical and natural products syntheses.
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