Chinese Journal of Chemistry最新文献

Silylation of C–H bond has been established to be an important strategy toward construction of complex organosilicons. Still, the state-of-the-art is mostly limited to intramolecular reactions or limited to employment of thiophenes or reactive arene reagents. Herein, rhodium-catalyzed intermolecular C–H silylation of indoles has been realized using silacyclobutanes as a silylating reagent, affording a variety of C2-silylated indoles. This chelation-assisted C–H silylation system proceeds well with a broad substrate scope with 100% atom-economy.

Porous organic polymers (POPs) have shown great potential as organic cathode materials (OCMs) for advanced lithium-ion batteries (LIBs). However, OCMs still face challenges such as insufficient output voltages. In this work, we report the design and synthesis of two dihydrophenazine-based POPs (denoted as TPBPA-DHP and PPT-DHP) with multiple p-type redox-active sites. When employed as OCMs for LIBs, both TPBPA-DHP and PPT-DHP cathodes exhibit high voltage platform characteristics, achieving ultrahigh output voltages of 3.59 and 3.61 V, respectively, along with remarkable energy densities of 536.8 and 502.1 Wh·kg^–1. Benefiting from their highly crosslinked structures and robust skeletons, both POP cathodes exhibit long cycle stability, retaining 72.7% and 70.8% of their capacities after 1000 cycles at 0.5 A·g^–1. Ex situ FT-IR spectra and EPR measurements were conducted to elucidate the redox mechanism involving anion interactions with p-type redox-active centers. Moreover, the PPT-DHP//graphite full cell delivers a high average discharge capacity of 129.2 mAh·g^–1 at 0.1 A·g^–1, retaining 76.9% of its initial capacity after 1000 cycles at 0.5 A·g^–1. This study provides valuable insights into the molecular design and synthesis of p-type POPs for the next generation high-voltage LIBs.

Mechanically interlocked networks (MINs) provide a versatile platform for engineering materials that combine mechanical strength with dynamic adaptability. Their performance hinges on the constrained intramolecular motion of mechanical bonds, so the deliberate selection of capping groups is essential for tailoring properties. Herein, we develop an innovative capping strategy for mechanical bonds by employing graphene oxide (GO) as the capping unit, enabling the construction of a new class of mechanically interlocked networks (^GOMINs) with enhanced mechanical performance. ^GOMINs benefit both from the reinforcing effect of GO as a nanofiller and its innovative use as a capping unit that creates continuous mechanical bonds, collectively improving their mechanical strength and adaptability. Compared to the non-interlocked control sample, ^GOMINs exhibit greater fracture strength (maximum stress: 9.4 vs. 3.6 MPa), higher toughness (22.3 vs. 9.7 MJ/m³), and increased elongation at break (359% vs. 328%). Notably, despite these significant enhancements, ^GOMINs maintain good energy dissipation capacity and thermomechanical stability owing to the constrained intramolecular motion of mechanical bonds. This strategy endows ^GOMINs with distinctive properties, providing a promising platform for the design of advanced composite materials with enhanced and tunable multifunctionality.

The direct construction of C(sp³)−C(sp²) bonds from operationally convenient, synthetically versatile, and readily accessible building blocks serves as a key driving force for innovation in synthetic organic chemistry. These scaffolds enhance drug properties, facilitating the development and clinical translation of lead compounds. In this work, we report the first use of the synergistic effect between Co and Ce LMCT catalysis, presenting an effective photocatalytic strategy for the decarboxylative Heck type coupling reaction of primary, secondary, and tertiary aliphatic carboxylic acids. Under mild conditions, this method achieves the effective coupling of C(sp³) and C(sp²) motifs, demonstrating excellent functional group tolerance and offering significant potential for the late-stage modification of bioactive carboxylic acids. Notably, this transformation proceeds without the need for external oxidants or pre functionalization of the carboxylic acids, with H₂ and CO₂ as the sole byproducts.

Construction of biologically interesting tryptanthrin-derived N,O-ketals was enabled via Cu(II)-catalyzed enantioselective addition of alcohols and tert-butyl hydroperoxide to tryptanthrin-derived N-Boc ketimines. Stereoselective activation of the electrophiles was possible using structurally confined chiral catalysts although such electrophiles suffered from the drawbacks such as low reactivity or steric hindrance around the reaction center. The protocol tolerated variations in both the tryptanthrin part and the alcohol scopes, and the products could be obtained with up to 99% ee and in up to 99% yield. Gram-scale reaction was possible, and functional group transformations could also be realized. X-ray diffraction experiments confirmed the configuration of tryptanthrin-derived N-Boc ketimine as well as the absolute configuration of the product.

LiCoO₂ (LCO) is a widely used cathode material for lithium-ion batteries due to its high specific capacity and good rate capability. However, its practical application at high voltages (≥4.6 V) is severely limited by several critical issues, resulting in poor cycle stability and capacity fading. To address these challenges, LCO with LaF₃ & LaOF nanophases modification was synthesized via a solid-state method, based on a synergetic strategy applying LaF₃ fast-ion-conducting coating to improve the interfacial ionic transport meanwhile constructing corrosion-resistant LaOF to suppress degradation. Through the electrochemical performance tests at high voltages (≥4.65 V), the optimal LCO-0.2LaF possesses superb high-voltage electrochemical performance: the initial capacity equals 193.0 mA·h·g^–1 with the retention of 91.1% after 100 cycles (1 C, 3.0–4.65 V); even at 1 C (3.0–4.70 V) the initial capacity is 207.7 mA·h·g^–1 and the retention is 76.6% after 100 cycles. Structural characterizations, including in-situ XRD, SEM, HRTEM, and XPS, etc., reveal that the synergetic modification of LaF₃ and LaOF nanophases can effectively suppress O^2– peroxidation, Co dissolution and the drastic contraction and expansion of the lattice, thereby inhibiting the irreversible H3 → H1-3 → O1 phase transition above 4.65 V.

Modulating the photophysical of organic solid-state functional materials is crucial for advancing supramolecular chemistry and materials science. Here, we present a π-conjugation enhanced charge-transfer strategy to turn on the photothermal conversion properties of crown ether cocrystals. Three crown ethers (H₁, H₂, and H₃) bearing different π-conjugated moieties are synthesized, exhibiting enhanced solid-state luminescence upon increasing molecular conjugation. In addition, three sets of host–guest cocrystals are constructed via charge-transfer (CT) interactions between these electron-rich crown ethers and electron-deficient 1,2,4,5-tetracyanobenzene (TCNB). Based on the variations in CT interactions, the resulting cocrystals transform from primarily photoluminescent behavior to efficient photothermal conversion. Detailed structural and spectroscopic analyses reveal that the extent of π-donor/π-acceptor overlap within the cocrystals is the dominant factor governing their tunable photophysical properties.