Angewandte Chemie International Edition最新文献

"A turning point in my career was exploring the molecular design of responsive polymers and macromolecular materials as a postdoctoral scholar… My group has fun by laughing, both in lab and group meeting, as well going on fun outings like group cookouts on the beach…" Find out more about Benjamin McDonald in his Introducing… Profile.

Porous liquids (PLs) are a new type of fluid sorbent investigated mainly for the separation of gas mixtures. Here, we explore their application to the separation of miscible liquids, using MEG/water (MEG=monoethylene glycol) and EtOH/water as proof-of-principle. Recovery of used MEG is industrially important but its extraction into conventional solvents from water is difficult. PLs ZIF-8@PDMS (PL1, PDMS=polydimethylsilicone) or ZIF-8@sesame oil (PL2) each consisting of 25 wt % of the hydrophobic microporous material ZIF-8 dispersed in PDMS or sesame oil respectively, were formulated and found to be exceedingly physically stable to sedimentation. A 5 nm PEEK membrane was used to provide a permeable barrier between the PL and the alcohol/water phase. MEG was selectively extracted through the membrane from approximately 50 : 50 wt % MEG/water mixtures into the PL phase and this procedure could be applied repeatedly. It was effective for MEG/water mixtures as dilute as 3 : 97 wt %. The PL could also be regenerated (80 °C at 0.01 bar) and re-used, suggesting its potential for continuous, cyclic extraction. Furthermore, PL3 (silicalite-1@PDMS) was effective in selective alcohol extraction from beverages. It shows potential for lowering the alcohol concentration in gin or wine due to its excellent chemical stability and nontoxicity. Overall, we show that the enhanced adsorption properties of PLs due the presence of empty pores, which provides unusually high gas solubilities, also makes them, in principle, applicable to liquid-liquid separations.

Platinum-based supported intermetallic alloys (IMAs) demonstrate exceptional performance in catalytic propane dehydrogenation (PDH) primarily because of their remarkable resistance to coke formation. However, these IMAs still encounter a significant hurdle in the form of catalyst deactivation. Understanding the complex deactivation mechanism of supported IMAs, which goes beyond conventional coke deposition, requires meticulous microscopic structural elucidation. In this study, we unravel a nonclassical deactivation mechanism over a PtZn/γ-Al₂O₃ PDH catalyst, dictated by the PtZn to Pt₃Zn nanophase transformation accompanied with dezincification. The physical origin lies in the metal support interaction (MSI) that enables strong chemical bonding between hydroxyl groups on the support and Zn sites on the PtZn phase to selectively remove Zn species followed by the reconstruction towards Pt₃Zn phase. Building on these insights, we have devised a solution to circumvent the deactivation by passivating the MSI through surface modification of γ-Al₂O₃ support. By exchanging protons of hydroxyl groups with potassium ions (K) on the γ-Al₂O₃ support, such a strategy significantly minimizes the dezincification of PtZn IMA via diminished metal-support bonding, which dramatically reduces the deactivation rate from 0.2044 to 0.0587 h^-1. These findings decode the nonclassical PDH deactivation mechanism over supported IMA catalysts and elaborate a new logic for the design of high-performance IMA based PDH catalysts with long-term stability.

Cytochrome P450 2D6 (CYP2D6) is a key enzyme that mediates the metabolism of various drugs and endogenous substances in humans. However, its biological role in drug-drug interactions especially mechanism-based inactivation (MBI), and various diseases remains poorly understood, owing to the lack of molecular tools suitable for selectively monitoring CYP2D6 in complex biological systems. Herein, using a tailored molecular strategy, we developed a fluorescent probe BDPM for CYP2D6. BDPM exhibits excellent specificity and imaging capability for CYP2D6, making it suitable for the real-time monitoring of endogenous CYP2D6 activity in living bio-samples. Therefore, our tailored strategy proved useful for constructing the highly selective and enzyme-activated fluorescent probes. BDPM as a molecular tool to explore the critical roles of CYP2D6 in the pathogenesis of diseases, high-throughput screening of inhibitors and intensive investigation of CYP2D6-induced MBI in natural systems.

Proteomics is a powerful method to comprehensively understand cellular posttranslational modifications (PTMs). Owing to low abundance, tryptic peptides with PTMs are usually enriched for enhanced coverage by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Affinity chromatography for phosphoproteomes by metal-oxide and pan-specific antibodies for lysine acetylome allow identification of tens of thousands of modification sites. Lysine methylation is a significant PTM; however, only hundreds of methylation sites were identified by available approaches. Herein we report an aryl diazonium based chemoselective strategy that enables enrichment of monomethyllysine (Kme1) peptides through covalent bonds with extraordinary sensitivity. We identified more than 10000 Kme1 peptides from diverse cell lines and mouse tissues, which implied a wide lysine methylation impact on cellular processes. Furthermore, we found a significant amount of methyl marks that were not S-adenosyl methionine (SAM)-dependent by isotope labeling experiments.

The excessive and prolonged use of antibiotics contributes to the emergence of drug-resistant S. aureus strains and potential dysbacteriosis-related diseases, necessitating the exploration of alternative therapeutic approaches. Herein, we present a light-activated nanocatalyst for synthesizing in situ antimicrobials through photoredox-catalytic click reaction, achieving precise, site-directed elimination of S. aureus skin infections. Methylene blue (MB), a commercially available photosensitizer, was encapsulated within the Cu^II-based metal-organic framework, MOF-199, and further enveloped with Pluronic F-127 to create the light-responsive nanocatalyst MB@PMOF. Upon exposure to red light, MB participates in a photoredox-catalytic cycle, driven by the 1,3,5-benzenetricarboxylic carboxylate salts (BTC^-) ligand presented in the structure of MOF-199. This light-activated MB then catalyzes the reduction of Cu^II to Cu^I through a single-electron transfer (SET) process, efficiently initiating the click reaction to form active antimicrobial agents under physiological conditions. Both in vitro and in vivo results demonstrated the effectiveness of MB@PMOF-catalyzed drug synthesis in inhibiting S. aureus, including their methicillin-resistant strains, thereby accelerating skin healing in severe bacterial infections. This study introduces a novel design paradigm for controlled, on-site drug synthesis, offering a promising alternative to realize precise treatment of bacterial infections without undesirable side effects.

We incorporate Se into the 3D halide perovskite framework using the zwitterionic ligand: SeCYS (⁺NH₃(CH₂)₂Se^-), which occupies both the X^- and A⁺ sites in the prototypical ABX₃ perovskite. The new organoselenide-halide perovskites: (SeCYS)PbX₂ (X=Cl, Br) expand upon the recently discovered organosulfide-halide perovskites. Single-crystal X-ray diffraction and pair distribution function analysis reveal the average structures of the organoselenide-halide perovskites, whereas the local lead coordination environments and their distributions were probed through solid-state ⁷⁷Se and ²⁰⁷Pb NMR, complemented by theoretical simulations. Density functional theory calculations illustrate that the band structures of (SeCYS)PbX₂ largely resemble those of their S analogs, with similar band dispersion patterns, yet with a considerable band gap decrease. Optical absorbance measurements indeed show band gaps of 2.07 and 1.86 eV for (SeCYS)PbX₂ with X=Cl and Br, respectively. We further demonstrate routes to alloying the halides (Cl, Br) and chalcogenides (S, Se) continuously tuning the band gap from 1.86 to 2.31 eV-straddling the ideal range for tandem solar cells or visible-light photocatalysis. The comprehensive description of the average and local structures, and how they can fine-tune the band gap and potential trap states, respectively, establishes the foundation for understanding this new perovskite family, which combines solid-state and organo-main-group chemistry.

Lithium-sulfur batteries (LiSBs) with high energy density still face challenges on sluggish conversion kinetics, severe shuttle effects of lithium polysulfides (LiPSs), and low blocking feature of ordinary separators to LiPSs. To tackle these, a novel double-layer strategy to functionalize separators is proposed, which consists of Co with atomically dispersed CoN₄ decorated on Ketjen black (Co/CoN₄@KB) layer and an ultrathin 2D Ti₃C₂T_x MXene layer. The theoretical calculations and experimental results jointly demonstrate metallic Co sites provide efficient adsorption and catalytic capability for long-chain LiPSs, while CoN₄ active sites facilitate the absorption of short-chain LiPSs and promote the conversion to Li₂S. The stacking MXene layer serves as a microscopic barrier to further physically block and chemically anchor the leaked LiPSs from the pores and gaps of the Co/CoN₄@KB layer, thus preserving LiPSs within efficient anchoring-conversion reaction interfaces to balance the accumulation of "dead S" and Li₂S. Consequently, with an ultralight loading of Co/CoN₄@KB-MXene, the LiSBs exhibit amazing electrochemical performance even under high sulfur loading and lean electrolyte, and the outperforming performance for lithium-selenium batteries (LiSeBs) can also be achieved. This work exploits a universal and effective strategy of a double-layer functionalized separator to regulate the equilibrium adsorption-catalytic interface, enabling high-energy and long-cycle LiSBs/LiSeBs.

In the pursuit of next-generation ultrahigh-energy-density Li-O₂ batteries, it is imperative to develop an electrolyte with stability against the strong oxidation environments. N,N-dimethylacetamide (DMA) is a recognized solvent known for its robust resistance to the highly reactive reduced oxygen species, yet its application in Li-O₂ batteries has been constrained due to its poor compatibility with the Li metal anode. In this study, a rationally selected hydrofluoroether diluent, methyl nonafluorobutyl ether (M3), has been introduced into the DMA-based electrolyte to construct a localized high concentration electrolyte. The stable -CH₃ and C-F bonds within the M3 structure could not only augment the fundamental properties of the electrolyte but also fortify its resilience against attacks from O₂ ^- and ¹O₂. Additionally, the strong electron-withdrawing groups (-F) presented in the M3 diluent could facilitate coordination with the electron-donating groups (-CH₃) in the DMA solvent. This intermolecular interaction promotes more alignments of Li⁺-anions with a small amount of M3 addition, leading to the construction of an anion-derived inorganic-rich SEI that enhances the stability of the Li anode. As a result, the Li-O₂ batteries with the DMA/M3 electrolyte exhibit superior cycling performance at both 30 °C (359^th) and -10 °C (120^th).

Reported herein is the first total synthesis of the poly-pseudoindoxyl natural product baphicacanthcusine A. The synthesis leverages the oxidative rearrangement of indoles to pseudoindoxyls to install vicinal pseudoindoxyl heterocycles in a diastereoselective manner. Key steps include an acid-mediated cyclization/indole transposition, two diastereoselective oxidative ring contractions, and a site-selective C-H oxygenation. The synthesis of the oxidation precursors was guided by recognition of an element of hidden symmetry. This work provides a foundation for the chemical synthesis of other poly-pseudoindoxyl alkaloids.