Angewandte Chemie最新文献

Silicon/carbon (Si/C) composite anodes are among the most promising candidates for high-energy-density lithium-ion batteries but suffer from severe volume fluctuation and interfacial degradation during cycling. Herein, we report a water-processable covalent-and-supramolecular polymeric binders (CSPBs) that synergistically dissipate mechanical stress and promote Li⁺ transport to stabilize the Si/C anode interface. The CSPBs integrate poly(acrylic acid) (PAA), amine-terminated eight-arm poly(ethylene glycol) (8arm-PEG-NH₂), and benzo-21-crown-7/secondary ammonium host–guest complexes through amidation during electrode fabrication. The covalent linkages impart strong structural integrity, while the reversible supramolecular interactions act as sacrificial bonds to dissipate stress arising from Si volume expansion. Additionally, oxygen-rich PEG chains form continuous Li⁺ conduction pathways, enabling efficient ion transport. As a result, the CSPB-2-based Si/C anode delivers a high specific capacity of 582.0 mAh g⁻¹ after 265 cycles at 1C, with superior rate capability than the electrodes based on PAA or solely covalently cross-linked binders (CCBs). Kinetic analysis reveals an enhanced Li⁺ diffusion coefficient, confirming the improved ionic conductivity of the binder system. This work demonstrates a new strategy for integrating covalent anchoring and dynamic supramolecular adaptability within a sustainable, water-processable polymeric binder system, paving the way for the design of durable and high-performance silicon-based anodes.

Electrocatalytic reductive dehydroxylation is a promising strategy for sustainable synthesis of commodity and high-value-added chemicals but remains a formidable challenge due to the high dissociation energy of C─OH bond. Here, we report a selectively electrocatalytic reductive dehydroxylation of 1,4-butenediol (BED) to produce 3-buten-1-ol (BTO) over Cu nanowire arrays (Cu NWAs) under ambient conditions. A high BED conversion of ∼90.5% and a BTO selectivity of ∼80.2% are achieved at –0.9 V versus RHE. Even in a large-scale two-electrode H-type elecrolyser (1 L), the Cu NWAs stably exhibit a BED conversion of ≥ 92.3%, a BTO selectivity of ≥ 82.7%, and a BTO production rate of 190.8 mmol_·g_cat⁻¹_·h⁻¹ at an industrial current density of 200 mA cm⁻². Experimental and theoretical investigations reveal that the Cu surface facilitates the dissociation of C─OH bond in BED and the desorption of BTO, which thus promotes the selective dehydroxylation of BED to BTO. This work highlights a sustainable and efficient strategy for producing high-value-added chemicals.

We present di-tert-butyl peroxide (DTBP)-catalyzed long-wavelength light-induced Group 13, 14, and 15 elementalizations of alkenes and alkynes, through in situ production of tert-butyl radicals, followed by a hydrogen-atom-transfer process generating silyl, germyl, stannyl, alkyl, boryl, and phosphoryl radicals. This mild and photosensitizer-free methodology employing blue (450 nm)/green (530 nm)/orange (600 nm) LEDs affords high chemoselectivity and broad functional group tolerance compared to conventional use of shorter-wavelength light. Synthetic, spectroscopic, and computational data are consistent with a vibration-mediated photolysis mechanism of DTBP involving electronic excitation from vibrationally excited ground states (S₀μ_n) to the excited state (S₀μ_n→S_n transitions), driven by ultraweak absorption of long-wavelength visible light.

Für die nichtoxidative Ethandehydrierung zu Ethen wurden Katalysatoren mit isolierten Co²⁺-Spezies in den 6MR- (Co²⁺-Z₂) und 8MR-Fenstern ([Co(OH)]⁺-Z) eines SSZ-13-Zeolithen hergestellt. Die Co²⁺-Z₂-Spezies zeigten im Vergleich zu den [Co(OH)]⁺-Spezies eine unerwartet hohe Ethenbildungsgeschwindikeit. Der aktivste der entwickelten Katalysatoren, der Co²⁺-Z₂ enthält, übertrifft Analoga der kommerziellen K-CrO_x/Al₂O₃- und PtSn/Al₂O₃-Katalysatoren in Bezug auf die Ethenbildung.

The semi-hydrogenation of alkynols to enols represents a vital industrial reaction for fine chemical synthesis, yet developing highly selective non-noble metal catalysts remains an urgent challenge. Herein, we report a Co₃O₄ nanorod (Co₃O₄-NR) catalyst with abundant solid-frustrated Lewis pairs (SFLPs) on specifically exposed {110} facets, where coordinatively unsaturated Co²⁺ acts as Lewis acid site whilst the surface hydroxyl group serves as Lewis base site. The Co₃O₄-NR catalyst exhibits exceptional performance toward semi-hydrogenation from 3-butyn-1-ol to 3-buten-1-ol with a product yield of 88.2%, which is preponderate to other non-noble metal catalysts. Poisoning experiments, in situ DRIFTS and theoretical calculations verify that the SFLPs sites serve as intrinsic active centers for H₂ activation/dissociation and substrate adsorption. The hydrogenation of key intermediate (C₄H₇O*) is identified as the rate-determining step, where H^δ+ species strongly tethered to surface −OH group suppresses over-hydrogenation and thereby enhances the semi-hydrogenation selectivity. Projected density of states (PDOS) analysis reveals an accelerated hydrogenation kinetics via d–p orbital hybridization between Co 3d orbitals and C 2p orbitals in C₄H₇O*. This work advances the design of efficient and cost-effective SFLPs-based heterogeneous catalysts, which shows potential application in the synthesis of fine chemicals.

Direct ethanol fuel cells (DEFCs) are recognized as a promising energy conversion technology due to their high energy density and the renewable, eco-friendly nature of ethanol. However, their commercialization is hindered by the lack of anode catalysts that simultaneously offer high activity, stability, and selectivity toward the C1 pathway in the ethanol oxidation reaction (EOR). Herein, we report a rationally designed Pd₂Ga₁-ZrO₂@NC electrocatalyst, in which Pd₂Ga₁ alloy nanoparticles are anchored on a nitrogen-doped carbon-encapsulated ZrO₂ nanoframework. In alkaline media, this catalyst exhibits exceptional EOR performance, achieving a remarkable mass activity of 27.3 A mg_Pd⁻¹, 3.6 and 21.8 times higher than those of Pd-ZrO₂@NC and commercial Pd/C, respectively. Furthermore, it demonstrates a high C1 pathway selectivity of 58.7% at 0.8 V_RHE and retains 48.9% of its initial activity after 2000 accelerated durability test cycles, significantly outperforming state-of-the-art benchmarks. Combined experimental and DFT studies reveal the crucial function of Ga as an electron donor, which reverses the electron transfer around Pd from outward (in Pd-ZrO₂@NC) to inward (in Pd₂Ga₁-ZrO₂@NC), creating an electron-rich Pd state. This electronic restructuring thereby lowers the *CO oxidation barrier, strengthens *OH adsorption, and enhances metal-support interaction, collectively boosting both the C1 pathway selectivity and the overall EOR performance. This work provides valuable insights for the design of high-performance alloy-oxide composite electrocatalysts.

Covalent organic frameworks (COFs) incorporating photoredox-active motifs show great promise as heterogeneous catalysts, yet their applications have been largely confined to one-step transformations. In this work, we design and synthesize a series of three-dimensional (3D) COFs with different π-extended dihydrophenazine cores to achieve superior photocatalytic performance. These 3D COFs exhibit excellent crystallinity, high surface areas, and remarkable chemical stability. More importantly, they can work as highly efficient and recyclable catalysts for photocatalytic tandem polymerization reactions using styrene and fluoroalkyl anhydrides as substrates, yielding fluoroalkylated polystyrene polymers with narrow dispersity. These COFs constitute the first examples as tandem photocatalysts toward polymerization reactions. Moreover, optimal energy level alignment and enhanced photophysical properties are identified as key factors contributing to their high efficacy. This work not only provides a viable design strategy for multifunctional COF catalysts, but also expands their utility in complex synthetic sequences involving tandem catalytic processes.

Anti-inflammatory colchicine therapy has emerged as a new era for atherosclerotic cardiovascular diseases. However, the therapeutic benefit of colchicine has not been clearly defined. Herein, we present a double coordination-driven approach to fabricate a stable metal-organic nano-assembly of colchicine (COL-TA-Zn) by uniting the tropolone ring of colchicine (COL), phenolic groups of tannic acid (TA), and Zn²⁺ ions. This design leverages the antioxidant and anti-inflammatory properties of COL and TA to create a nanoscale platform capable of scavenging radicals and modulating inflammatory pathways. Through robust Zn²⁺ coordination, the resulting COL-TA-Zn nanocomplexes exhibit enhanced stability under physiological conditions, ensuring efficient delivery and sustained bioactivity. In vitro assays confirm suppression of foam cell formation and multiple inflammatory mediators, suggesting significant potential for managing atherosclerosis by targeting both oxidative stress and inflammation. Intravenous administration of COL-TA-Zn in Apoe^−/− mice significantly reduces atherosclerotic plaque area, MMP-9, TNF-α, and reactive oxygen species (ROS) levels, thereby illustrating its superior anti-atherosclerotic efficacy compared to COL alone. These findings highlight the promise of the dual coordination-driven nanoplatform in cardiovascular disease treatment.

Covalent organic frameworks (COFs) incorporating photoredox-active motifs show great promise as heterogeneous catalysts, yet their applications have been largely confined to one-step transformations. In this work, we design and synthesize a series of three-dimensional (3D) COFs with different π-extended dihydrophenazine cores to achieve superior photocatalytic performance. These 3D COFs exhibit excellent crystallinity, high surface areas, and remarkable chemical stability. More importantly, they can work as highly efficient and recyclable catalysts for photocatalytic tandem polymerization reactions using styrene and fluoroalkyl anhydrides as substrates, yielding fluoroalkylated polystyrene polymers with narrow dispersity. These COFs constitute the first examples as tandem photocatalysts toward polymerization reactions. Moreover, optimal energy level alignment and enhanced photophysical properties are identified as key factors contributing to their high efficacy. This work not only provides a viable design strategy for multifunctional COF catalysts, but also expands their utility in complex synthetic sequences involving tandem catalytic processes.

We present di-tert-butyl peroxide (DTBP)-catalyzed long-wavelength light-induced Group 13, 14, and 15 elementalizations of alkenes and alkynes, through in situ production of tert-butyl radicals, followed by a hydrogen-atom-transfer process generating silyl, germyl, stannyl, alkyl, boryl, and phosphoryl radicals. This mild and photosensitizer-free methodology employing blue (450 nm)/green (530 nm)/orange (600 nm) LEDs affords high chemoselectivity and broad functional group tolerance compared to conventional use of shorter-wavelength light. Synthetic, spectroscopic, and computational data are consistent with a vibration-mediated photolysis mechanism of DTBP involving electronic excitation from vibrationally excited ground states (S₀μ_n) to the excited state (S₀μ_n→S_n transitions), driven by ultraweak absorption of long-wavelength visible light.