Angewandte Chemie最新文献

Precise stacking of distinct two-dimensional (2D) rigid slabs to build heterostructures has renewed the portfolio of 2D materials, e.g., magic-angle graphene, due to the emergence of exotic physical properties. Recently, single-crystal heterostructures of layered perovskites have emerged as an exciting branch, while it remains scarce to achieve strong ferroelectricity in this new heterostructure family. Here, we present the first ferroelectric of 2D perovskite heterostructures as single crystal, (EA₃Pb₂Br₇)EA₄Pb₃Br₁₀ (1, EA=ethylamine), by precisely tailoring inorganic sheets via a chemical molecular scissor. It has notable ferroelectricity of large spontaneous polarization (P_s~5.0 μC/cm²) and high Curie temperature (T_c~375 K). Structurally, its inorganic framework adopts a unique 2D heterostructure that contains two different rigid slabs of {EA₃Pb₂Br₇}_n and {EA₄Pb₃Br₁₀}_n. This motif is self-assembled by layer-by-layer clipping of rigid prototype sheets, using extra neopentylamine as a molecular chemical scissor. Unlike epitaxial growth, such a molecule-level stacking facilitates the growth of heterostructure single crystals. Combining its strong ferroelectricity and inherent anisotropy, crystal-based device of 1 exhibits an ultrahigh polarized-light sensitivity up to ~37 in self-powered mode, being the highest level of 2D perovskite ferroelectric family. Our work will facilitate the further development of ferroelectric materials for optoelectronic device applications.

Heterobimetallic μ-methylidyne complexes [WPt(μ₂-CH)(CO)₂L₂(Tp*)], where L₂=(PPh₃)₂, (PPh₃)(CO), (dppe), (PPh₃)(CNC₆H₂Me₃), have been obtained via the intermediacy of transient hydrido-μ-carbido complexes that undergo carbido-hydrido coupling to model a fundamental step in the proposed mechanism for Fischer–Tropsch synthesis.

Poly(lactic-co-glycolic acid) (PLGA) has been widely employed for various biomedical applications owing to its biodegradability and biocompatibility. The discovery of the stereocomplex formation between enantiomeric alternating PLGA pairs underscored its potential as high-performance biodegradable materials with diverse material properties and biodegradability. Herein, we have established a regio- and stereoselective ring-opening polymerization approach for the synthesis of stereocomplexed isoenriched alternating PLGA from racemic methyl-glycolide (rac-MG). The high sequence and tacticity control was accomplished by an optimized enantiopure scandium catalyst bearing a spiro-salen scaffold. Varying polymer stereoregularity P_m from 0.4 to 0.91 led to a transformation of the resulting alternating PLGA from amorphous to semicrystalline materials. Notably, the stereocomplexed alternating PLGA demonstrated enhanced melting transition temperature (T_m up to 191 °C) and crystallization rate. This regio- and stereocontrolled polymerization represented a versatile approach for the preparation of high-performance biodegradable PLGA materials.

Solid-state lithium (Li) metal batteries (SSLMBs) are considered as one of the most promising next-generation battery technologies due to their high energy density and intrinsic safety. However, interfacial issues such as side reactions and Li dendrite growth severely hinder the practical application of SSLMBs. In this contribution, we proposed a cationic built-in electrostatic field to drive the generation of an anion-derived dual-layered solid electrolyte interphase (SEI). The specific adsorption of tributylmethyl-phosphonium bis(trifluoromethanesulfonyl)imide (TMPB) cations onto negatively charged Li anode surface significantly prevents interfacial side reactions between vulnerable polyethylene oxide (PEO) and Li metal. More importantly, the formed cationic built-in electrostatic field induces the targeted trapping of Li-salt anions onto the Li metal surface, leading to the generation of an anion-derived dual-layered SEI, composed of a mechanically flexible organic-rich surface layer and a Li-ion conductive inorganic-rich bottom layer. As a result, the Li||Li cell demonstrated an extended lifespan of over 1900 hours with the reduced polarization voltage. The Li||LiFePO₄ full cell also exhibited excellent cycling stability, maintaining an average Coulombic efficiency of 99.7 % over 200 cycles at 0.5 C. This work provides valuable insights into mitigating interfacial degradation and promoting uniform Li deposition through surface electrostatic field regulation.

Recently, aqueous proton batteries have shown promise for electrochemical energy storage using MXene electrodes. However, designing high-performance MXene proton batteries remains challenging due to the inevitable hydrogen evolution reaction (HER), the vast chemical composition space of MXene, and the unclear proton transport mechanism. To tackle these challenges, we established a general descriptor based on structural units of MXenes, termed the octahedral net charge descriptor (Q_oct). This descriptor correlates well with HER activity, capacity, and proton transport performance. Based on the descriptor, prediction reveals a dual-proton storage mechanism per site in N-functionalized MXene. Meanwhile, the accuracy of the descriptor is verified across a broader MXene chemical space. Additionally, the kinetic process shows the topological transformation energy barrier of the interfacial solution is profoundly influenced by Q_oct, thereby impacting the proton transfer performance. This universal descriptor originates from the different electron filling states on the molecular orbitals of the octahedron. Overall, this work provides an efficient strategy for designing MXene proton batteries and can be extended to other battery and catalysis fields.

High capacity, selective recovery and separation of precious metals from complex aqueous solutions is essential but remains a challenge in practical applications. Here, we prepared a thiophene-modified aromatic porous organic cage (T-PAC) with high stability for precise recognition and recovery of gold. T-PAC exhibits an outstanding gold uptake capacity of up to 2260 mg/g with fast adsorption kinetics and high adsorption selectivity. It's also used to selectively recover gold from a variety of complex aqueous solutions in a stable and efficient manner. The theoretical calculations and dedicated experiments suggest that anion-π interactions between the [AuCl₄]⁻ and TFP fractions on T-PAC cooperated with S/N boning and redox effects play the decisive role in the highly efficient gold recovery performance.

“If I were not a scientist, I would be an artist. Both science and art strive to explore and explain the physical and emotional world around us… I recharge my batteries by playing chess. It helps me clear my mind and focus entirely on the pieces and strategy of the game…” Find out more about Nikolaos Eleftheriadis in his Introducing… Profile.

The global quest for clean energy and sustainable processes makes advanced membrane extremely attractive for energy-intensive industrial gas separations. Here, we disclose a series of ultra-high-performance gas separation membranes (PIM-3D-TB) from novel network polymers of intrinsic microporosity (PIM) that combine the advantages of solution processible PIM and small pore size distribution (PSD) of porous organic polymers (POP), which was synthesized by in situ copolymerization of triptycene-2,6-diamine as linear part and triptycene-2,6,13(14)-triamine (TTA) as crosslinker. The resulting PIM-3D-TB membranes demonstrated outstanding separation properties that outperformed the latest trade-off lines for H₂/CH₄ and O₂/N₂. They also showed an anti-trade-off effect by simultaneously enhancing gas permeability and gas-pair selectivity with increasing TTA content. The TTA crosslinking node increased the microporosity, and, shifted the PSD from the ultramicropore (<7 Å) toward the more size sieving submicropore (<4 Å) region. The post-treated TTA-75 displayed an exceptional H₂ permeability of 8000 Barrer and H₂/CH₄ selectivity of 208. These PIM-3D-TB membranes and their design protocol have unparalleled potential in the next generation of membranes for hydrogen purification and air separations.

The development of sustainable synthesis route to produce functional and bioactive polymer colloids has attracted much attention. Most strategies are based on the polymerization of monomers or crosslinking of prepolymers by enzyme- or cell-mediated reactions or specific catalysts in confined emulsions. Herein, a facile solution spray method was developed for spontaneous synthesis of microgels without use of confined emulsion, additional initiators/catalysts and deoxygenation, which addresses the challenges in traditional microgel synthesis. The polarization of air-water interface of the microdroplets can spontaneously split hydroxide ions in water to produce hydroxyl radicals, thereby initiating polymerization and crosslinking in air environment. This synthesis strategy is applicable to a variety of monomers and enables the fabrication of microgels with tunable chemical structures and variable sizes. Importantly, the synthesis route also allows for the preparation of enzyme- or drug-loaded microgels via the in situ encapsulation, which also display high enzymatic activity and stimuli-triggered drug release. Therefore, this work not only is of great significance to macromolecular science and microdroplet chemistry, but also may bring new insights into cellular biochemistry and even prebiotic chemistry due to the prevalence of microdroplets in the environment.