Latest ArticlesAmong the large energy storage batteries, the sodium ion batteries (SIBs) are attracted huge interest due to the fact of its abundant raw materials and low cost, and has become the most promising secondary battery. Tunnel-type sodium manganese oxides (TMOs) are industrialized cathode materials because of their simple synthesis method and proficient electrochemical performance. Na0.44MnO2 (NMO) is considered the best candidate material for all tunnel-type structural materials. In this paper, the research progress in charge and discharge of cathode materials for tunnel-type structural SIBs is reviewed, the redox mechanism and all sorts of synthesis methods and different coating methods lead to different morphology and electrochemical properties of materials and the classification of electrolytes and non-aqueous electrolytes. The development and utility of aqueous solutions are discussed, and the mechanism is analyzed. Summarized the cationic potential of the transition metal oxide for tunnel structure, plays a vital role in predicting and designing the cathode material of this structure. In addition, the future opportunities and challenges for such tunnel-type SIBs in this field are described in detail.
This brief review reports the recent advancement of metallic glasses and metallic glass nanostructures for functional electrocatalytic applications. Metallic glasses (MGs) or amorphous metals result from quenching the melts at a high cooling rate (e.g., 106 K/s), bypassing crystallization. Metallic glasses are devoid of long-range translational order, no defects like grain boundaries, and multiple elements included. Due to these unique structural features, MG's show distinct and valuable mechanical, physical and chemical properties and therefore were widely studied as a structural material for decades. Even though MGs were proposed for catalytic applications earlier, a comprehensive study or attempt to apply these materials successfully in electrocatalytic applications are few since the intrinsic surface area is comparably lesser. A rejuvenated interest among the research community for applying various novel strategies in catalytic applications of MGs is highlighted in the present review. Theoretical approaches using density functional theory (DFT) and high-throughput screening assisted with machine learning paradigm advances the discovery of new MGs, which demonstrated high potential for catalytic applications. We focus on the basic features and recent advances in the MGs for catalytic applications like electrocatalytic water splitting reactions like HER, OER, fuel cell reactions like ORR, alcohol oxidation reactions like MOR, EOR, and degradation of harmful organic dyes from the industrial effluents. The presently advancing strategies for enhancing the performance of these metallic glass electrocatalysts through nanostructuring and high-throughput screening are discussed. The unique atomic-scale structural mechanism of the metallic glasses, which can favor the development of high-performance electrocatalysts even comparable to currently available precious-metal-based catalysts, will be discussed. Finally, we also give future directions on designing novel and superior metallic glass-based advanced catalysts.
Two-dimensional (2D) materials composed of single pnictogen element, namely, 2D pnictogens (e.g., black phosphorus, arsenene, antimonene and bismuthine), have recently showed remarkable potential for biomedical applications, especially after the rapid development of black phosphorus. With unique optical and electronic properties, 2D pnictogens are considered as promising nanoagents for biosensors, diagnosis and therapy. In this review, after brief introduction of the structure, properties, synthesis strategies, and biocompatibility of 2D pnictogens, their biomedical applications including anti-tumor, anti-inflammation, anti-bacterial, neurodegenerative treatment and tissue repairing are reviewed. The major obstacles and opportunities of 2D pnictogens are also discussed. This review provides a short yet timely summary on the synthesis and biomedical applications of emerging 2D pnictogens.
Graphene oxide (GO), as a metal-free and readily available carbocatalyst, has been extensively applied in catalytic organic transformations. This minireview aims to give an overview of the progress on the application of native GO as a catalyst for various organic transformations in the past decade (mainly from 2011 to 2020).
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.
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.
A copper-catalyzed three-component reaction of alkenes, cycloketone oximes and DABCO·(SO2)2 is developed, which provides a convenient route for the synthesis of diverse (E)-cyanoalkylsulfonyl alkenes in moderate to good yields with excellent regio- and stereoselectivity. A broad substrate scope with excellent functional group tolerance is observed. A plausible radical pathway is proposed, which involves copper-catalyzed ring-opening CC bond cleavage of O-acyl oxime and insertion of sulfur dioxide. During the reaction process, cyanoalkyl radical and cyanoalkylsulfonyl radical are the key intermediates.
Although fluorobis(phenylsulfonyl)methane (FBSM) and its cyclic analog 2-fluoro-1, 3-benzodithiole-1, 1, 3, 3-tetraoxide (FBDT) possess similar physicochemical properties, Shibata et al. found that FBSM failed to undergo nucleophilic monofluoromethylation of aldehydes regardless of the reaction conditions attempted (using various organic and inorganic bases). However, it was later discovered by Hu et al. that the nucleophilic monofluoromethylation could be accomplished by employing lithium hexamethyldisilazide (LiHMDS) as a base. Herein, we present an in-depth computational investigation into the intriguing effects of reagent structure and bases on the nucleophilic monofluoromethylation of aldehydes. The computations reveal the 1, 4-diazabicyclo[2.2.2]octane (DABCO) catalyzed nucleophilic monofluoromethylation of benzaldehyde with acyclic FBSM is a thermodynamically unfavorable process mainly due to the destabilizing O···O lone pair repulsions in FBSM product, whereas such repulsion could be largely avoided in FBDT product because of its constrained five-membered ring structure. Employing LiHMDS as a base can not only facilitate the nucleophilic monofluoromethylation via Li–O interactions but also render the monofluoromethylation of benzaldehyde with FBSM thermodynamically favored.
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.
A new relay C–H functionalization of di([1, 1′-biphenyl]-2-yl)phosphine oxide to obtain esterified and hydroxylated products with different hypervalent iodines as oxidants under palladium catalysis is disclosed. This reaction provides a more effective and concise strategy for the synthesis of novel structural hybrid-arylcyclophosphorus ligand precursors with a wide range of substrates and good functional group tolerance.