Latest ArticlesThe intrinsic clustering behavior and kinetically sluggish conversion process of lithium polysulfides seriously limit the electrochemical reversibility of sulfur redox reactions in lithium-sulfur (Li-S) batteries. Here, we introduce molybdenum pentachloride (MoCl5) into the electrolyte which could coordinate with lithium polysulfides and inhibit their intrinsic clustering behavior, subsequently serving as an improved mediator with the bi-functional catalytic effect for Li2S deposition and activation. Moreover, the coordination bonding and accelerated conversion reaction can also greatly suppress the dissolution and shuttling of polysulfides. Consequently, such polysulfide complexes enable the Li-S coin cell to exhibit good long-term cycling stability with a capacity decay of 0.078% per cycle after 400 cycles at 2 C, and excellent rate performance with a discharge capacity of 589 mAh/g at 4 C. An area capacity of 3.94 mAh/cm2 is also achieved with a high sulfur loading of 4.5 mg/cm2 at 0.2 C. Even at -20 ℃, the modified cell maintains standard discharge plateaus with low overpotential, delivering a high capacity of 741 mAh/g at 0.2 C after 80 cycles. The low-cost and convenient MoCl5 additive opens a new avenue for the effective regulation of polysulfides and significant enhancement in sulfur redox conversion.
An electronic circular dichroism (ECD)-based chiroptical sensing method has been developed for β- and γ-chiral primary amines via a C–H activation reaction. With the addition of Pd(OAc)2, the flexible remote chiral primary amine fragment in the bidentate ligand intermediate was fixed to form a cyclopalladium complex, producing an intense ECD response. The correlation between the sign of Cotton effects and the absolute configuration of substrates was proposed, together with theoretical verification using time-dependent density functional theory (TDDFT). Chiroptical sensing of an important drug raw material was performed to provide rapid and accurate information on the absolute optical purity. This work introduces an alternative perspective of C–H activation reaction as well as a feasible chiroptical sensing method of remote chiral amines.
Achieving artificial simulations of multi-step energy transfer processes and conversions in nature remains a challenge. In this study, we present a three-step sequential energy transfer process, which was constructed through host-guest interactions between a piperazine derivative (PPE-BPI) with aggregation-induced emission (AIE) and cucurbit[7]uril (CB[7]) in water to serve as ideal energy donors. To achieve multi-step sequential energy transfer, we employ three distinct fluorescent dyes Eosin B (EsB), Sulforhodamine 101 (SR101), and Cyanine 5 (Cy5) as energy acceptors. The PPE-PBI-2CB[7]+EsB+SR101+Cy5 system demonstrates a highly efficient three-step sequential energy transfer mechanism, starting with PPE-PBI-2CB[7] and transferring energy successively to EsB, SR101, and finally to Cy5, with remarkable energy transfer efficiencies. More interestingly, with the progressive transfer of energy in the multi-step energy transfer system, the generation efficiency of superoxide anion radical (O2•–) increased gradually, which can be used as photocatalysts for selectively photooxidation of N-phenyltetrahydroisoquinoline in an aqueous medium with a high yield of 86% after irradiation for 18 h. This study offers a valuable investigation into the simulation of multi-step energy transfer processes and transformations in the natural world, paving the way for further research in the field.
A sp2 carbon-conjugated covalent organic framework (BDATN) was modified through γ-ray radiation reduction and subsequent acidification with hydrochloric acid to yield a novel functional COF (named rBDATN-HCl) for Cr(VI) removal. The morphology and structure of rBDATN-HCl were analyzed and identified by SEM, FTIR, XRD and solid-state 13C NMR. It is found that the active functional groups, such as hydroxyl and amide, were introduced into BDATN after radiation reduction and acidification. The prepared rBDATN-HCl demonstrates a photocatalytic reduction removal rate of Cr(VI) above 99% after 60 min of illumination with a solid-liquid ratio of 0.5 mg/mL, showing outstanding performance, which is attributed to the increase of dispersibility and adsorption sites of rBDATN-HCl. In comparison to the cBDATN-HCl synthesized with chemical reduction, rBDATN-HCl exhibits a better photoreduction performance for Cr(VI), demonstrating the advantages of radiation preparation of rBDATN-HCl. It is expected that more functionalized sp2 carbon-conjugated COFs could be obtained by this radiation-induced reduction strategy.
An unprecedented 2,3-arylacylation reaction of allenes with aryl iodides and aldehydes was developed by resorting to Pd/NHC synergetic catalysis. It is the first time that allene was introduced into transition metal and NHC synergetic catalysis, which demonstrated a versatile three-component reaction pattern, thus enabling two C-C bonds forged regioselectively in the reaction. The important reaction intermediates were successfully captured and characterized by HRMS analysis, and the migrative insertion of allene to the Ph-Pd species was identified as the reaction rate-limiting step by kinetic experiments.
As a novel two-dimensional (2D) material, MXenes are anticipated to have a significant impact on future aqueous energy storage and conversion technologies owing to their unique intrinsic laminar structure and exceptional physicochemical properties. Nevertheless, the fabrication and utilization of functional MXene-based devices face formidable challenges due to their susceptibility to oxidative degradation in aqueous solutions. This review begins with an outline of various preparation techniques for MXenes and their implications for structure and surface chemistry. Subsequently, the controversial oxidation mechanisms are discussed, followed by a summary of currently employed oxidation characterization techniques. Additionally, the factors influencing MXene oxidation are then introduced, encompassing chemical composition (types of M, X elements, layer numbers, terminations, and defects) as well as environment (atmosphere, temperature, light, potential, solution pH, free water and O2 content). The review then shifts its focus to strategies aiming to prevent or delay MXene oxidation, thereby expanding the applicability of MXenes in complex environments. Finally, the challenges and prospects within this rapidly-growing research field are presented to promote further advancements of MXenes in aqueous storage systems.
Chirality, ubiquitous in living matter, plays vital roles in a series of physiological processes. The clarification of the multiple functions of chirality in bioapplications may provide innovative methodologies for engineering anti-tumor agents. Nevertheless, the related research has been rarely explored. In this study, the chiral supramolecular l/d-cysteine (Cys)-Zn2+-indocyanine green (ICG) nanoparticles were constructed through the coordination interaction between l/d-Cys and Zn2+, followed by the encapsulation of ICG. Experimental findings revealed that the d-Cys-Zn2+-ICG exhibited 17.31 times higher binding affinity toward phospholipid-composed liposomes compared to l-Cys-Zn2+-ICG. Furthermore, driven by chirality-specific interaction, a 2.07 folds greater cellular internalization of d-Cys-Zn2+-ICG than l-Cys-Zn2+-ICG was demonstrated. Additionally, the triple-level chirality-dependent photothermal, photodynamic and Zn2+ releasing anti-tumor effects of l/d Cys-Zn2+-ICG in vitro were verified. As a result, the d-formed nanoparticles achieved 1.93 times higher anti-tumor efficiency than the l-formed ones. The triple-level chirality-mediated anti-tumor effect highlighted in this study underscores the enormous potential of chirality in biomedicine and holds substantial significance in improving cancer therapeutic efficacy.
Ferroptosis in combination with immune therapy emerges as a promising approach for cancer therapy. Herein, dual-responsive metal-polyphenol coordinated nanomedicines were developed for pH/glutathione (GSH)-responsive synergistic ferroptosis and immunotherapy. Our innovative strategy involves the development of a manganese-polyphenol coordinated nanostructure, leveraging the biocompatibility of bovine serum albumin (BSA) as a template to encapsulate the anticancer drug sorafenib. The tumor microenvironment (pH/GSH) prompts the disassembly of MnO2 and epigallocatechin gallate (EGCG), thereby releases the anticancer payload. Concurrently, MnO2 acts to deplete intracellular GSH, which in turn suppresses glutathione peroxidase activity, leading to an accumulation of lipid peroxides with cell ferroptosis. Additionally, the release of Mn2+ ions bolster the cyclic guanosine monophosphlic acid (GMP)-adenosine monophosphlic acid (AMP) synthase-stimulator of interferon gene (cGAS-STING) pathway, which, in conjunction with the immunogenic cell death (ICD) effect induced by tumor cell apoptosis, significantly promotes dendritic cell (DC) maturation and enhances the presentation of tumor antigens. This successively ignites a robust innate and adaptive immune response. Both in vitro and in vivo experiments have demonstrated that the concurrent administration of ferroptosis-inducing and immune-stimulating therapies can significantly inhibit tumor growth.
Homogeneous C–H and C–X borylation via transition-metal-catalysis have undergone rapid development in the past decades and become one of the most practical methods for the synthesis of organoboron compounds. However, the catalysts employed in homogeneous catalysis are generally expensive, sensitive, and difficult to separate from the reaction mixture and reuse. With the rapid development of heterogeneous catalysis, heterogeneous C–H and C–X borylation have emerged as highly efficient and sustainable approaches towards the synthesis of organoboron compounds. This review aims to highlight the recent advances in the synthesis of organoboron compounds employing heterogeneous C–H and C–X borylation strategies. We endeavor to shed light on new perspectives and inspire further research and applications in this emerging area.
Candida albicans is one of the most common pathogens causing invasive fungal infections, with a mortality rate of up to 20%–50%. Amphotericin B (AmB), a biopharmaceutics classification system (BCS) IV drug, significantly inhibits Candida albicans. AmB is primarily administered via oral and intravenous infusion, but severe infusion adverse effects, nephrotoxicity, and potential hepatotoxicity limit its clinical application. Deep eutectic solvents (DESs), with excellent solubilization ability and skin permeability, are attractive for transdermal delivery. Herein, we used DESs to deliver AmB for antifungal therapy transdermally. We first prepared and characterized DESs with different stoichiometric ratios of choline (Ch) and geranate (Ge). DESs increased the solubility of AmB by a thousand-fold. In vitro and in vivo, skin permeation studies indicated that DES1:2 (Ch and Ge in 1:2 ratio) had the most outstanding penetration and delivered fluorescence dye to the dermis layer. Then, DES1:2-AmB was prepared and in vitro antifungal tests demonstrated that DES1:2-AmB had superior antifungal effects compared to AmB and DES1:2. Furthermore, DES1:2-AmB was skin-irritating and biocompatible. In conclusion, DES-AmB provides a new and effective therapeutic solution for fungal infections.