Latest ArticlesThe potential use of ammonia (NH3) as a hydrogen energy carrier has generated significant interest in developing efficient catalysts for producing NH3 under mild conditions. The main obstacles for NH3 synthesis are the activation of the N≡N bond and the desorption of NH3 from the catalyst surface. Here, we report the use of C60 to overcome these challenges. Through electron transfer, migration, and feedback between C60 and Ru, there is a balance of electronic density at the Ru active sites and a shift in the d-band center. This simultaneously satisfies the electronic requirements for enhancing N2 activation while weakening NH3 adsorption, thereby circumventing the bottlenecks in NH3 synthesis under mild conditions. Meanwhile, anchoring of C60 accelerates hydrogen spillover and enhances the exchangeability of hydrogen species in the ZrH2 support, as well as expose a greater number of B5 sites of Ru entities, resulting in the co-optimization of hydrogen migration and nitrogen activation. As a consequence, the NH3 synthesis rate of the C60-Ru/ZrH2 catalyst is approximately twice that of the Ru/ZrH2 catalyst at 400 ℃ and 1 MPa. This study shows that doping C60 represents a fundamentally different approach compared to traditional promoters for catalytic NH3 synthesis. We anticipate that this strategy may be generalized to generate widespread interest in the catalysis of NH3 synthesis.
Mechanistic studies of the transmetalation of the trifluoromethyl group from an ionic Cu(Ⅰ) complex Q+[Cu(CF3)2]− to a well-defined chlorinated Cu(Ⅲ) complex trans-[Cu(CF3)2(Cl)(CH2CN)]−Q+ was reported. The combined experimental and computational results including kinetics of the process, reactions in the presence of excess chloride salt, or radical scavengers such as TEMPO or 1, 1-diphenylethene (DPE), 1, 4-dinitrobenzene (DNB), strongly support a concerted metathesis pathway.
The etiology and pathogenesis of Parkinson's disease (PD) are complex, and its precise pathology remains poorly defined. Emerging evidence suggest that the dysregulation of intracellular copper ion (Cu2+) is tightly associated with PD progression. However, the dynamic interplay between Cu2+ and different stages of PD progression is not fully understood yet. In this study, we developed four Cu2+ fluorescent sensors and evaluated their blood-brain barrier (BBB) penetration efficiency. Among them, PD-Cu-3 exhibited a 62.15% BBB penetration ability and was successfully utilized for real-time monitoring of Cu2+ fluctuations in PD model cells and mice. We first observed an initial increase in Cu2+ level during the early phase PD model cells, followed by a decline in prolonged conditions due to ATP7A-mediated intracellular Cu2+ efflux. Furthermore, in vivo imaging results from PD model mice and brain slices revealed Cu2+ fluctuations across different PD stages, with an elevation in the acute stage and a subsequent reduction in the subacute stage. This study not only provided a new insight into Cu2+ metabolism in PD progression but also help understanding of PD pathology and searching potential therapeutic approaches.
Switchable chirality in confined environments is central to biological regulation, yet artificial systems enabling reversible chirality control remain challenging. Herein, we report a redox-responsive supramolecular chirality system constructed from phenylalanine-modified viologen (d/l-PheVio⋅2Br) and cucurbit[8]uril (CB[8]) in aqueous solution. The formation of 1:1 host-guest complex triggers pronounced chirality amplification, evident from characteristic induced circular dichroism (ICD) signals. Upon chemical reduction, these ICD signals vanish abruptly, replaced by unusual CD signals from viologen radical cations, demonstrating chirality transfer enabled by the confined environment. The redox-switchable process exhibits exceptional reversibility and repeatability over multiple cycles. These findings deepen our understanding of supramolecular chirality arising from host-guest complexation in confined spaces at the molecular level, offering new perspectives for designing stimuli-responsive chiral materials.
Aqueous zinc-ion batteries (ZIBs) have gained tremendous interests by virtue of their intrinsic safety, low cost and favorable theoretical capacities. As the promising candidates of cathode materials of ZIBs, ammonium vanadates (NVO) have captured widespread attentions owing to their tunable chemical properties and enhanced structural stabilities owing to the existence of NH4+ in the [VO]n layers. However, the pristine NVO fails to meet the expectations due to the strong interlayer electrostatic repulsion and comparatively sluggish transfer kinetics, which necessitates the exploration of appropriate modification strategies to fully dig its potential. Herein, this review systematically summarizes five core molecular engineering strategies, intercalation, defect, interfacial, doping, and structural engineering strategies, and their significances in modulating structural and electrochemical properties of NVO are elaborately discussed. Moreover, the perspectives on the future developments and potential energy-related applications of NVO are presented. This review is anticipated to deepen the researchers' understandings of the potentials of molecular engineering strategies on improving zinc-ion storage capabilities of cathode materials, and further promote the practicality of NVO in ZIBs.
Ultra-thick electrodes (UTEs) hold great promise for high-energy-density lithium-ion batteries (LIBs), yet the practical application is hindered by challenges in precise fabrication and reaction kinetics modification. In this contribution, a solvent-free processing method is introduced to tailor UTEs through layer-by-layer fabrication with positive, uniform, and negative gradient porosity from the separator side to the current collector side, denoted as P-UTEs, U-UTEs, and N-UTEs. In contrast to conventional slurry coating, the proposed solvent-free approach effectively circumvents capillary stress, thereby facilitating the fabrication of crack-free UTEs (> 300 µm) while simultaneously mitigating environmental toxicity concerns. The three-layer N-UTEs (> 220 µm) with a gradient porosity of (~34%, ~31%, ~27%) deliver an exceeding areal capacity over 5 mAh/cm2 at 0.29 mA/cm2 and a high-capacity retention over 62% at 2.9 mA/cm2, indicating a favorable balance between the areal capacity and the high-rate behavior. Detailed mechanistic simulations reveal that the multi-center reaction pathways enabled by enhanced ionic accessibility in N-UTEs significantly improve reaction kinetics. This work offers new insights into the gradient porosity tailoring for high-areal-capacity and high-rate UTEs for the next generation LIBs.
α-d-Fructofuranoside derivatives are prevalent in natural products, exhibiting diverse bioactivities. Herein, a stereoselective glycosylation method for synthesizing α-d-fructofuranosides using fructofuranosyl fluorides as donors is described. Glycosylation of 1,3,4,6-tetra-O-benzoyl-2-d-fructofuranosyl fluoride, promoted by tris(pentafluorophenyl)borane, proved highly effective, yielding glycosylation products in high yields (up to 98%) with primary alcohols, thiols, N- and C-nucleophiles. Furthermore, β-(2→6) cyclodisaccharide di-d-fructose-2,6′:6,2′-dianhydride (DFA Ⅳ), a disaccharide enzymatically derived from levan, was chemically synthesized through orthogonal glycosylation reactions and hydrogen-bond-mediated aglycone delivery involving thioglycosides and glycosyl fluorides for the first time.
The carbon-centered radical induced C‒C bond cleavage in strained cyclopropane is a well-known process. However, achieving similar transformations in unstrained rings is still challenging. Herein, a novel inexpensive Cu-catalyzed strategy for the carbon-centered radical-mediated ring-opening/amination or esterification cascade of unstrained α-haloalkyl cycloketone derivatives is presented. Differ from the classical Dowd-Beckwith ring expansion reaction, a ring opening cascade occurred successfully under a simple copper/base catalytic system, yielding useful distal unsaturated amides and esters in good to excellent yields. Mechanistic studies and DFT calculations indicate that the halogen-bonding interaction between halide and base is crucial for the activation of the C‒Br bond. Furthermore, the formation of a bicyclic Cu-complex via bi-dentate coordination, including O–Cu–•CH2, seems to be a crucial factor that promotes ring opening rather than the conventional ring expansion. This work would not only bring new vitality for the radical-mediated C‒C bond cleavage, but also highlight the potential of protocol for synthesizing bioactive molecules.
gem–Difluorovinyl compounds and silicon-containing compounds are valuable structural units in organic and medicinal chemistry. However, they are mostly found separately in most compounds. In this study, we present a photocatalytic approach for the synthesis of gem–difluorovinylsilanes, using readily accessible silylboronic pinacol esters as reagents. Through a radical transfer strategy, this method overcomes the limitation of their high oxidation potential. Biological assays further confirmed that several target compounds exhibited moderate to potent antifungal activity against plant pathogens, including Botrytis cinerea, Setosphaeria turcica and Rhizoctonia solani.
The stereodivergent coupling via photoredox/transition metal catalysis has emerged as a powerful tool to construct diverse alkenes in both E and Z configurations. Despite well-established catalytic systems involving late transition metals, the early transition metal catalyzed stereodivergent synthesis of alkenes still remains underdeveloped. Herein in this work, a stereodivergent reductive C(sp2)-C(sp3) coupling between cycloketone oximes and vinyl halides has been achieved by tunable photoredox/Ti dual catalysis, providing a facile access to a broad scope of cyano-substituted (fluoro)alkenes with high efficiency and controlled E/Z selectivity. Several products exhibited promising antifungal activities.
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