Catalytically Generated Allyl Cu(I) Intermediate via Cyclopropene Ring-Opening Coupling en Route to Allylphosphonates

An efficient generation of functionalized allyl copper­(I) species via cyclopropene ring-opening coupling reaction is reported, which enables stereoselective access to allylphosphonates. Mechanistic studies uncovered stereochemistry to be controlled by both ligand and substrate electronics, with the latter likely arising from pronounced arene-Cu­(I) interaction in electron-deficient substrates. The study unravels a novel approach to access functionalized nucleophilic allylcopper species upon which three-component coupling reactions might be developed

Rechargeable Aluminum-Ion Battery Based on MoS₂ Microsphere Cathode

In recent years, a rechargeable aluminum-ion battery based on ionic liquid electrolyte is being extensively explored due to three-electron electrochemical reactions, rich resources, and safety. Herein, a rechargeable Al-ion battery composed of MoS₂ microsphere cathode, aluminum anode, and ionic liquid electrolyte has been fabricated for the first time. It can be found that Al³⁺ intercalates into the MoS₂ during the electrochemical reaction, whereas the storage mechanisms of the electrode material interface and internal are quite different. This result is confirmed by ex situ X-ray photoelectron spectroscopy and X-ray diffraction etching techniques. Meanwhile, this aluminum-ion battery also shows excellent electrochemical performance, such as a discharge specific capacity of 253.6 mA h g^–1 at a current density of 20 mA g^–1 and a discharge capacity of 66.7 mA h g^–1 at a current density of 40 mA g^–1 after 100 cycles. This will lay a solid foundation for the commercialization of aluminum-ion batteries

Dual-Salt Mixed Electrolyte for High Performance Aqueous Aluminum Batteries

A dual-salt electrolyte with 5 M Al(OTF)3 and 0.5 M LiOTF is proposed for aqueous aluminum batteries, which can effectively prevent the corrosion caused by the hydrogen evolution reaction. With the addition of LiOTF in the electrolyte, the solvation phenomenon has changed with the coordination mode of Al3+ conversion from an all octahedral structure to a mixed octahedral and tetrahedral structure. This change can reduce the hydrogen bond between water molecules, which will minimize the occurrence of hydrogen evolution reactions. Moreover, the new electrolyte improves the cycle life of the battery. With MnO as the cathode, 2.1 V high charging platform and 1.5 V high discharge platform can be obtained. The electrochemical stability window (ESW) has been improved to 3.8 V. The first cycle capacity is up to 437 mAh g–1, which can be maintained at 103 mAh g–1 after 100 cycles. This work provides solutions for the future development of electrolyte for aqueous aluminum batteries

Oxygen Vacancies Boosted Proton Intercalation Kinetics for Aqueous Aluminum–Manganese Batteries

Aluminum-ion batteries have garnered an extensive amount of attention due to their superior electrochemical performance, low cost, and high safety. To address the limitation of battery performance, exploring new cathode materials and understanding the reaction mechanism for these batteries are of great significance. Among numerous candidates, multiple structures and valence states make manganese-based oxides the best choice for aqueous aluminum-ion batteries (AAIBs). In this work, a new cathode consists of γ-MnO2 with abundant oxygen vacancies. As a result, the electrode shows a high discharge capacity of 481.9 mAh g–1 at 0.2 A g–1 and a sustained reversible capacity of 128.6 mAh g–1 after 200 cycles at 0.4 A g–1. In particular, through density functional theory calculation and experimental comparison, the role of oxygen vacancies in accelerating the reaction kinetics of H+ has been verified. This study provides insights into the application of manganese dioxide materials in aqueous AAIBs

Asymmetric Nitrone Synthesis via Ligand-Enabled Copper-Catalyzed Cope-Type Hydroamination of Cyclopropene with Oxime

We report realization of the first enantioselective Cope-type hydroamination of oximes for asymmetric nitrone synthesis. The ligand promoted asymmetric cyclopropene “hydronitronylation” process employs a Cu-based catalytic system and readily available starting materials, operates under mild conditions and displays broad scope and exceptionally high enantio- and diastereocontrol. Preliminary mechanistic studies corroborate a Cu^I-catalytic profile featuring an olefin <i>metalla</i>-retro-Cope aminocupration process as the key C–N bond forming event. This conceptually novel reactivity enables the first example of highly enantioselective catalytic nitrone formation process and will likely spur further developments that may significantly expedite chiral nitrone synthesis