New Journal of Chemistry最新文献

A new mesoporous SBA-15-immobilized Schiff base and phosphine mixed bidentate palladium(II) complex [SBA-15-N,P-Pd(OAc)₂] was prepared via immobilization of 3-aminopropyltriethoxysilane onto SBA-15, followed by the condensation with 2-(diphenylphosphino)benzaldehyde and then coordination with Pd(OAc)₂. With the use of 4 mol% of SBA-15-N,P-Pd(OAc)₂ as a catalyst, the cascade addition/cyclocarbonylation reaction of o-iodoarylcarbodiimides with nucleophiles proceeded smoothly in bioderived 2-MeTHF at 80 °C with K₂CO₃ as a base under 7 bar of CO to deliver a wide array of 2-heteroquinazolin-4(3H)-ones in good to excellent yields with wide tolerance of functional groups. The SBA-15-N,P-Pd(OAc)₂ complex could be facilely recovered by simple filtration of the reaction mixture and recycled at least eight times without any significant loss of catalytic efficiency.

Small biomolecules are crucial for the maintenance of biochemical homeostasis in living organisms, and the accurate detection of their levels is of great significance. Herein, we prepared a novel composite material, namely, Fe single-atom catalysts embedded in reduced graphene oxide (FeSACs@RGO), and applied it to the electrochemical detection of small biomolecules. FeSACs@RGO integrated the merits of single-atom catalysts with atomically dispersed active sites and reduced graphene oxide with a large specific surface area, thus exhibiting desirable electron transfer capability and electrochemical catalytic performance. The FeSACs@RGO-based electrochemical sensor enabled the sensitive detection of uric acid (UA) and hydrogen peroxide (H₂O₂). The limits of detection for UA and H₂O₂ were 3.06 μM and 5.11 μM, respectively. Moreover, it demonstrated satisfactory selectivity, repeatability and stability. More importantly, the sensor has been successfully applied to detect UA and H₂O₂ in serum samples. This work is expected to provide a reference strategy for the design of sensing materials and further application in detection.

It is essential to develop sustainable approaches for fabricating energy devices using natural materials like lignocellulosic biomass. Lignin, which is most abundant in nature, serves as a tribo-positive filler due to its chemical morphology. Herein, we isolated lignin from the raw hardwood via the soda pulping method and utilized the isolated lignin in developing composite nanofibers with polyvinylidene fluoride (PVDF), i.e., PVDF-lignin nanofibers (PLNFs), via an electrospinning technique. Triboelectric characteristics of PLNFs with different lignin concentrations were evaluated against polytetrafluorethylene (PTFE). An enhancement in performance was observed compared to raw PVDF. The electrical output of triboelectric nanogenerators (TENGs) made using PLNFs depends on their structural features, polarizability, dielectric properties, force, and frequency of vibration. Thus, the P10-L5 TENG (PVDF 10 wet% with 5% lignin) generates the highest output power density of approximately ∼60 mW m⁻². The high performance of the P10-L5 TENG is attributed to the uniform dimensions of nanofibers and high surface charge accumulation on the surface of PLNFs. Lignin-based TENGs exhibit excellent stability and endurance, enduring 10 000 cycles at 1 Hz, 3 Hz, and 5 Hz frequencies. The PLNFs produced a high-power output, while the indium tin oxide-coated PET sheets provide strength and flexibility, resulting in a stable, durable, and sustainable TENG system.

The different properties of Ba₂NiPdO₆ and Ba₂NiPtO₆ double perovskite alloys are analyzed using a density functional theory simulation performed with Wien2k. First, structural optimization computed by adopting the Generalized Gradient Approximation (GGA) showed that both alloys indeed have a cubic C 1b structure with a ferromagnetic phase. Other approximation methods, including the GGA plus Hubbard potential (GGA+U), the GGA+U+spin orbit coupling (GGA+U+SOC) and the modified Bece–Johnson potential (mBJ), have demonstrated that these compounds are half-metallic and have a band gap suitable for solar applications. The overall magnetic moment is 4µ_B per formula unit (fu), with Ni atoms contributing significantly. Furthermore, the low reflectivity and high optical absorption of double perovskites indicate their potential for various optoelectronic fields beyond photovoltaics.

A ternary BiVO₄/CoO_x/Ag photoanode was developed via hydrothermal synthesis and photodeposition for efficient solar water splitting. The synergistic integration of p-type CoO_x and plasmonic Ag enhances charge separation through p–n heterojunction formation, increases carrier density, and improves visible-light harvesting and hole transfer kinetics. The modified photoanode achieves a high photocurrent density of 3.2 mA cm⁻² at 1.23 V vs. RHE, with 85% charge injection efficiency and excellent stability over 3 h. Gas evolution confirms near-theoretical H₂:O₂ stoichiometry and faradaic efficiency >88%, demonstrating highly efficient and stable overall water splitting.

Following the emergence of dye sensitized solar cells (DSSCs), considerable research attention has been devoted to further enhancing their performance through multiple approaches. Among those, enhancing light harvesting efficiency remains an effective route to augment the photocurrent generation and, consequently, the overall power conversion efficiency of DSSCs. Incorporation of scattering material layers on the photoanode layer has shown significant promise in this regard, especially with respect to N719 based DSSCs. Similar work with organic dye based DSSCs has been very scarce. Therefore, in this study, we have explored the morphology-dependent scattering effect of TiO₂ using three different structures, such as sphere-like particles (TS), novel twisted fiber-like structures (TF), and hierarchical flower-like architectures (TNF) in a DSSC configuration employing Y123 organic dye and a Cu-based redox shuttle. The structural, morphological, optical, and photoelectrochemical properties were analyzed to understand the crystalline properties, scattering efficiencies, and charge dynamics in the organic dye based DSSC device. Among the studied morphologies, TS exhibited the highest efficiency of 5.26% and a higher photocurrent density of 8.47 mA cm⁻², representing a 23.7% improvement in efficiency over the device without a scattering layer and 13.3% higher than the commercial scattering material. This enhancement is primarily attributed to efficient photon management, enabled by their superior light scattering ability compared to other structures. Our findings reveal that each morphology demonstrated unique contribution towards light scattering and charge dynamics under outdoor conditions. Interestingly, under indoor lighting, scattering effects were found to be negligible, providing new insights into morphology-specific light management in low light environments.

Continuous catalytic processes that convert CO₂ into solid carbon offer a promising route for carbon-negative chemical production. In this work, we investigate coupled CO₂ methanation–dry reforming–carbon capture under new operating conditions to significantly improve the carbon capture efficiency. Using the same experimental apparatus as our prior study, we varied the total gas flow rate and implemented a water trap in the carbon-capture unit. Their effects on the reactant conversion, product gas composition, and solid carbon yield were measured. Key results show that the optimized flow conditions (intermediate residence time) and water-trap integration lead to solid carbon production, with the carbon yield increasing from 20% for the original configuration to 60%. The CO₂ and CH₄ conversions remained high (with a stable H₂/CO ratio of 1.6 in the syngas product), indicating that enhanced carbon capture was achieved without sacrificing the syngas generation performance. Characterization of the captured carbon by electron microscopy and Raman spectroscopy revealed the formation of abundant carbon nanotubes/fibers with improved crystallinity under the new conditions. Therefore, the coupled methanation-reforming reactor with flow optimization affords improved control and efficiency for CO₂-to-solid-carbon conversion, enabling the effective sequestration of CO₂ as a stable solid.

We report a concise and practical method for the synthesis of 3-fluoroquinolines via a decarboxylative Mannich-type addition of α,α-difluoro-β-ketoesters with N-aryl imines in the presence of Yb(OTf)₃. The method is broadly applicable to a variety of N-aryl imines and α,α-difluoro-β-ketoesters, affording the corresponding 3-fluoroquinolines in moderate to high yields. Control experiments strongly suggest that Yb(OTf)₃, likely converted in situ into YbCl₃ in the presence of NaCl, promotes both the cyclisation to the quinoline ring and the decarboxylation step. Unlike conventional quinoline synthesis, which often requires harsh conditions, this approach provides a milder, versatile, and efficient entry into 3-fluoroquinoline scaffolds, which are valuable motifs in medicinal chemistry.

Transition metal-catalyzed dehydrogenative annulation reactions utilizing α-carbonyl sulfoxonium ylides constitute an efficient strategy for ring skeleton construction. These versatile ylide reagents can function as both C–H activation substrates and carbene precursors. Herein, we employ density functional theory calculations to systematically investigate the mechanism of ruthenium-catalyzed dehydrogenative annulation between α-carbonyl sulfoxonium ylide 1 and maleimide 2, with special focus on the dual role of sulfoxonium ylides. The C–H activation step is identified as rate-determining, wherein both the nucleophilic carbon and the carbonyl oxygen may serve as the coordination center for the directing group in 1. Computational analyses reveal that the nucleophilic carbon-directed pathway exhibits both kinetic and thermodynamic advantages, establishing it as the predominant coordination mode. The subsequent steps proceed sequentially with relatively lower barriers: Ru–carbene formation, followed by migratory insertion, and concluding with reductive elimination. We also investigate how Ru–carbene formation at different stages affects catalytic activity. Ru–carbene formation before C–H activation makes C–H activation kinetically unfeasible, while its occurrence after migratory insertion increases the barrier of migratory insertion, making this pathway uncompetitive. This work can provide fundamental insights into the bifunctional reactivity of sulfoxonium ylides in organometallic chemistry.

SO₂, owing to its serious health and environmental risks, has driven the development of highly efficient materials for its capture and sequestration. In this work, two novel, pyridine-based, electron-rich, porous organic poly(Schiff-base) networks—PHPSN-Py and PAPSN-Py—were constructed through catalyst-free Schiff-base condensation reactions. Their chemical and porous structures were characterized in detail. The influence of their significantly different spatial topologies on their structures and properties was investigated. These two porous materials, despite their relatively low BET surface areas of 8 and 22 m² g⁻¹, demonstrated excellent SO₂ capture and separation performance, with adsorption uptakes up to 11.9 mmol g⁻¹ (273 K, 1 bar), 7.6 mmol g⁻¹ (298 K, 1 bar) and 1.62 mmol g⁻¹ (298 K, 0.01bar), owing to their nitrogen-rich skeletons that are beneficial for deep sulfurization. This very competitive performance exceeded those of many previously reported nanoporous materials. Meanwhile, the IAST selectivities for SO₂/CO₂ (10/90, v/v) could reach 141.8 and 89.4 at 273 and 298 K and 1 bar. This study represents a novel pyridine-based, porous organic material and confirms its intrinsic potential for the highly efficient removal of SO₂. This could provide valuable insights into developing new porous desulfurization materials.