Latest ArticlesImproving the transfer hydrogenation of N-heteroarenes is of key importance for various industrial processes and remains a challenge so far. We reported here a microcapsule-pyrolysis strategy to quasi-continuous synthesis S, N co-doped carbon supported Co single atom catalysts (Co/SNC), which was used for transfer hydrogenation of quinoline with formic acid as the hydrogen donor. Given the unique geometric and electronic properties of the Co single atoms, the excellent catalytic activity, selectivity and stability were observed. Benefiting from the quasi-continuous synthesis method, the as-obtained catalysts provide a reference for the large-scale preparation of single atom catalysts without amplification effect. Highly catalytic performances and quasi-continuous preparation process, demonstrating a new and promising approach to rational design of atomically dispersed catalysts with maximum atomic efficiency in industrial.
Lewis base-catalyzed annulations of allenoates have been one of the most powerful synthetic strategies for the synthesis of various valuable cycles, especially in the preparation of biologically active natural products and pharmaceuticals. Generally, the effective Lewis bases mainly include tertiary phosphine, NHC and tertiary amine catalysts, among those catalysis, tertiary amine Lewis bases have proven to be effective catalysts for a range of synthetic transformations. In the past decades, tremendous progress involving tertiary amines-promoted cycloaddition of allenoates has been made in the chemoselective construction of valuable motifs. This review describes a comprehensive and updated summary of tertiary amine Lewis base-promoted annulation reactions of allenoates. Diverse reactivities, chemoselectivties and detailed reaction mechanisms will be highlighted in this review.
α-(Trifluoromethyl)styrene and its derivatives have found wide applications in the fields of pharmaceuticals, agrochemicals, and advanced materials. They are also versatile trifluoromethyl-containing building blocks for the preparation of various trifluoromethyl-containing, fluorine-containing or nonfluorinated compounds. Recently, great efforts have been made to develop diverse reactions for rapidly accessing a wide range of valuable gem-difluoroalkenes and gem-difluoroalkylated compounds via defluorinative reaction or the defluorinative ipso-functionalization reaction of α-(trifluoromethyl)styrenes, respectively. In contrast, α-(trifluoromethyl)styrenes remain notably underdeveloped with respect to their use in cycloaddition and hydroaddition reaction with retaining of three CF bonds. This short review herein is aimed to summarize the recent progress on the cycloaddition and hydroaddition reaction including nucleophilic, radical and transition metal-catalyzed addition of α-(trifluoromethyl)styrenes without accompanying defluorination.
Volatile organic compound (VOC) pollution has a serious impact on human and urgently needs to be controlled through the development of new methods and catalytic materials. Compared with traditional thermal catalytic oxidation, the synergistic photothermocatalysis is regarded as a green and environmentally friendly strategy for organic compound pollutant removal, which can promote spontaneous heating of the surface of catalysts to achieve thermal catalytic reaction conditions via harvesting light irradiation. In this paper, a monolithic photothermocatalyst was synthesized through coating graphene oxide (GO) and MnOx in turn on a commercially available melamine sponge, where the GO mainly acted as a photothermal conversion layer to heat the catalytically active MnOx. This monolithic catalyst presented excellent photo-induced activity for formaldehyde elimination under ambient conditions (~90% degradation ratio in 20 min for ~160 ppm initial concentration formaldehyde), and meanwhile possessed a high catalytic durability for multiple cycles. The kinetic study demonstrated that this photothermocatalytic process followed a pseudo-second-order kinetics. Finally, we proposed a possible formaldehyde degradation pathway based on in situ DRIFTS examination.
DNA methylation represents a major type of DNA modifications that play key roles in diverse biological processes. With the recent development of highly selective and sensitive bioanalytical techniques, N6-methyladenine (6mA) has been characterized as an important internal DNA modification dynamically occurring in multiple eukaryotes including humans. Increasing evidence has indicated that 6mA may act as a novel epigenetic modification involved in regulation of development, stress response and diseases such as cancer and neurodegenerative disorders. We review herein the recent advances in the detection and functional studies of 6mA modification, with special emphasis on its biological consequences and human health relevance as well as its dynamic regulation by various types of methyltransferases, demethylases and 6mA-binding proteins. It can be envisaged that further chemical and biological studies of 6mA modification will lead to a better understanding about its potentially important roles in normal and pathological biological processes.
The properties of two-dimensional (2D) materials are highly dependent on their phase and thickness. Various phases exist in tin disulfide (SnS2), resulting in promising electronic and optical properties. Hence, accurately identifying the phase and thickness of SnS2 nanosheets is prior to their optoelectronic applications. Herein, layered 2H-SnS2 and 4H-SnS2 crystals were grown by chemical vapor transportation and the crystalline phase of SnS2 was characterized by X-ray diffraction, ultralow frequency (ULF) Raman spectroscopy and high-resolution transmission electron microscope. As-grown crystals were mechanically exfoliated to single- and few-layer nanosheets, which were investigated by optical microscopy, atomic force microscopy and ULF Raman spectroscopy. Although the 2H-SnS2 and 4H-SnS2 nanosheets have similar optical contrast on SiO2/Si substrates, their ULF Raman spectra obviously show different shear and breathing modes, which are highly dependent on their phases and thicknesses. Interestingly, the SnS2 nanosheets have shown phase-dependent electrical properties. The 4H-SnS2 nanosheet shows a current on/off ratio of 2.58 × 105 and excellent photosensitivity, which are much higher than those of the 2H-SnS2 nanosheet. Our work not only offers an accurate method for identifying single- and few-layer SnS2 nanosheets with different phases, but also paves the way for the application of SnS2 nanosheets in high-performance optoelectronic devices.
Though Olefin-linked covalent organic frameworks (oCOFs) possess excellent π-electron delocalization, the barely reversible olefin linkage brings challenges for oCOFs' synthesis and functionalization. Here, we synthesize new oCOFs with tertiary amine knots which have twisted configuration and electron-donating nature. Investigation into the structural variation and photoelectric performance shows that the twisted configuration of oCOF-TFPA could favor to the intramolecular charge transfer process and reduce the possibility of aggregation-caused quenching. Photoelectrical measurements and electric band structure calculation both verify the superiority of this oCOFs' structure in photoelectric sensing.
Herein, we report an unprecedented regiospecific oxidative Mizoroki-Heck type reaction for the synthesis of α-difluoromethyl homoallylic alcohols. The reaction shows broad substrate scopes and high functional group tolerance. Late-stage functionalization of complex biologically active molecules demonstrates the synthetic potential of this transformation. Mechanistic study supports the involvement of MnBr2 catalyzed radical 1, 2-silyl transfer.
Targeting RIPK1 is a promising strategy for the treatment or alleviation of acute lung injury (ALI). SZM594, a benzothiazole compound previously developed by our research group, possessed good dual-targeting receptor-interacting protein kinase 1 (RIPK1) and RIPK3 activity and anti-necroptosis activity as well as acceptable in vivo efficacy. In this study, the cyclopropyl moiety of SZM594 was modified based on a structure-based design strategy. The resulting cyclohexanone-containing analogue 41 improved the selectivity toward RIPK1 over RIPK3 and the anti-necroptosis activity was also increased compared with those of SZM594. More importantly, compound 41 could inhibit the tumor necrosis factor-α (TNF-α) expression in lipopolysaccharide (LPS)-induced peritoneal macrophage cell model, and significantly alleviate LPS-induced ALI in a mouse model. This compound could significantly inhibit the expressions of the phosphorylation of RIPK1 and down-stream RIPK3 and mixed lineage kinase domain-like protein (MLKL). Thus, these cyclohexanone-containing benzothiazole analogues represent promising lead structures for the discovery of novel protective agents of ALI.
As a two-dimensional carbon based semiconductor, C3N acts as a promising material in many application areas. However, the basic physical properties such as Raman spectrum properties of C3N is still not clear. In this paper, we clarify the Raman spectrum properties of multilayer C3N. Moreover, the stacking driven Raman spectra change of multilayer C3N is also discussed.
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