Chemistry - An Asian Journal最新文献

An enantiodivergent route was devised for accessing the two enantiomers of indolo[2,3-a]quinolizidine, which serve as a platform for the synthesis of Corynanthe alkaloids with dimorphic configurations at the C3 position. The cascade process, involving dipolar cycloaddition, N–O bond cleavage, and cyclization, minimizes the need for functional group elaboration. Subsequent alkylation, allylation, and ring-closing metathesis smoothly constructed the pentacyclic ring system embedded in yohimbine alkaloids. The inherent simplicity and efficiency of enzymatic kinetic resolution prove valuable for diverse structural derivatives.

The development of highly active and cost-effective electrocatalysts for the urea oxidation reaction (UOR) is critical for facilitating scalable and sustainable hydrogen production. Heterointerface engineering has emerged as an effective strategy to enhance UOR performance by modulating electronic structures and improving charge transfer kinetics. Herein, we designed and fabricate a 3D heterostructure NiMn/Ni₃S₂ supported on foam nickel (NiMn/Ni₃S₂/NF) via in situ growth of nickel-manganese layered double hydroxide (NiMn(OH)_x) on a self-supported sulfurized NF substrate. This unique petal architecture promotes active-site exposure and facilitates interfacial electron transfer between NiMn(OH)_x and Ni₃S₂, which significantly enhances UOR catalytic activity. The as-optimized NiMn/Ni₃S₂/NF catalyst exhibits exceptional performance, achieving a low potential of 1.352 V (vs. reversible hydrogen electrode [RHE]) at 100 mA cm⁻² and a Tafel slope of 13.34 mV dec⁻¹, outperforming most previously reported UOR catalysts. Moreover, the as-prepared NiMn/Ni₃S₂/NF catalyst demonstrates remarkable stability, retaining high catalytic activity and durability for over 120 h at 10 mA cm⁻². This study provides a rational strategy to design efficient and durable electrocatalysts for energy-related applications.

A simple and scalable ultrasonic-acid-assisted grafting method was applied to synthesize phosphorylated silica gel adsorbent (SGB-P2), which significantly enhanced the adsorption capacity and selectivity for uranium. The obtained SGB-P2 exhibited a maximum uranium adsorption capacity of 400 mg·g⁻¹ greatly surpassing those of the unmodified sample (50.54 mg·g⁻¹), and achieved ultrafast adsorption equilibrium within just 1 min and retained over 80% efficiency after five adsorption–desorption cycles. The adsorption process followed the pseudo-second-order kinetics and Langmuir isotherm models, indicating chemisorption-dominated monolayer adsorption. Combined spectroscopic analyses and density functional theory (DFT) calculations revealed that the coordination between uranium and the phosphate groups (P─O/P═O) constitutes the primary adsorption mechanism. This study demonstrates great potential for practical application of silica gel in the treatment of uranium-contaminated wastewater.

Electrochemical overall water splitting is one of the main choices to realize hydrogen energy. In this study, a simple strategy of self-growth of carbon nanotubes with the tip end of Co nanoparticles compound Fe-Nx/mesoporous carbon as bi-functional electrocatalyst is proposed. At high temperature, cobalt nanoparticles catalyze the self-growth of nitrogen-doped carbon nanotubes with a tip of cobalt particles from a metal-organic framework ZIF-8. FeTAPc as Fe and N resource is further adsorbed on the shell and then re-carbonized under 900°C to fix Fe-Nx on the polyhedron carbon shell to form bi-functional electrocatalyst (Fe-Nx/Co-NC-900). Fe-Nx/Co-NC-900 showed good OER (330 mV) and HER (239 mV) overpotential. As a result, the porous structure of Fe-Nx/Co-NC-900 and the interconnected three-dimensional carbon network promote the material transport. The self-growing carbon nanotubes improve the conductivity of the electrocatalyst and avoid aggregation. The high dispersion of two kinds of metal atoms and the mixed growth of metal nanoparticles co-endowed Fe-Nx/Co-NC-900 electrocatalyst with rich activity. In addition, Fe-Nx/Co-NC-900 has been used to assemble an electrochemical overall water splitting with a driving voltage of 1.67 V, which shows its practical application in electrochemical overall water splitting. This study provides enlightenment in application of hydrogen energy production.

In this study, the efficient design and synthesis of a novel peptide bioisosteres for selective folding into a hairpin-like structure has been reported. The peptide mimetic comprises β-alanine, L-leucine, α-amino isobutyric acid, m-nitro cinnamic acid has been synthesized via solution-phase coupling methods. A hairpin conformation and extended β-pleated parallel sheet assembly have been characterized in solution as well as in solid state. The key to this success was the use of β-alanine as a flexible amino acid that can accommodate a wide range of dihedral angles proximal to the binol core. In its solid state, the molecule adopts a hairpin conformation with two perpendicular naphthalene rings. The centrally located binol segment act as bioisosteres and nucleates a chain reversal in the hairpin conformation. Two intramolecular cross-strand hydrogen bonds stabilize the hairpin. Moreover, the intermolecular NH…O═C hydrogen bonds connect the hairpins into an infinitely extended parallel β-sheet. The structure is also stabilized by face to edge π-stacking interactions. This peptide bioisosteres represents a promising tool for foldamer design.

Early detection of pancreatic disease requires non-invasive, highly sensitive biomarker detection. Here, we report a fluorescence-based method for rapid, ultrasensitive detection of urinary trypsin without sample pretreatment. A π-extended pyrene fluorescent probe functionalized with four carboxylate groups was designed to facilitate selective interaction and micellar aggregation with protamine, a trypsin-cleavable substrate. Protamine-induced aggregation results in amplified fluorescence quenching, which is efficiently reversed by trypsin-mediated proteolysis. Trypsin cleavage reduces the arginine-rich positive charge density and length of protamine, disassembling the compound 1-protamine aggregates and recovering monomeric fluorescence, enabling highly sensitive detection. The sensing platform achieved a limit of detection (LOD) of 2.0 ng/mL in 10% human urine, highlighting its strong analytical performance. The developed sensor exhibited excellent selectivity and enabled reliable quantification of trypsin at sub-microgram levels (0.03–0.7 µg/mL) in 10% diluted human urine, making it suitable for early-stage pancreatic disease screening. Its clinical applicability was further validated in the presence of acute pancreatitis (AP)-inducing factors, including aspirin, ibuprofen, dexibuprofen, acetaminophen, 6-mercaptopurine, as well as ethanol and its metabolites (acetaldehyde and acetate). In addition, urine samples were successfully analyzed using a smartphone-integrated fluorescence detection system, highlighting its practicality and clinical potential for early pancreatic disease diagnosis.