RSC Advances最新文献

Polyurethane (PU)-based electrolyte has become one of the most important research directions because of its unique repeating ‘soft–hard’ segment co-polymer structure. Its ‘soft segment’ composition includes polyethylene oxide, polysiloxane, polycarbonate, cellulose and polyether. Among them, polyether-based polyurethane electrolytes (PPES) have the advantages of simple synthesis, molecular structure optimization and functional group modification, which can greatly improve the ionic conductivity of the system and form a good ion transport interface. To date, a few separate and detailed reviews of advances in PPES have been reported. In this paper, the research progress of PPES is reviewed from the aspects of structural design strategy, molecular synthesis, conductivity modification methods, specific functions and interfacial ion transport behavior in lithium metal batteries (LMBs). In addition, the synthetic route of PPES and the development prospect of PPES are discussed. We also provide guidance for developing high-performance PPES for next-generation LMBs.

β³-Amino acids are essential components in the synthesis of biologically active compounds. However, obtaining them in enantiomerically pure forms remains challenging. This study investigates a safe and efficient method for synthesizing enantiopure N-Boc-β³-amino acid methyl esters, incorporating both natural and unnatural side chains. The procedure avoids the use of expensive and toxic reagents, providing a safer alternative to the hazardous Arndt–Eistert homologation and cyanation reactions, which typically begin with enantiopure α-amino acids. The practical value of this transformation was demonstrated in the formal synthesis of sedum alkaloids.

This work presents a sustainable approach for synthesizing esters from carboxylic acids, amino acids and carbohydrates using a robust and eco-friendly chitosan-incorporated ionic liquid under solvent-free conditions. Ionic liquids with carbon chain lengths ranging from 3 to 8 were integrated into the chitosan molecule, resulting in a heterogeneous catalyst optimized for esterification reactions. Among these, the 6-carbon chain ionic liquid demonstrated superior catalytic activity and substrate tolerance. The catalyst's effectiveness was confirmed using advanced analytical techniques. The acidity of the ionic liquid was assessed by observing the interaction between the synthesized IL6 (1,4-bis(5-carboxypentyl)pyrazine-1,4-diium ([BCPPD][Br])) and p-nitroaniline via UV-Vis studies. Chitosan-IL6, an ionic liquid supported on chitosan, functions as a heterogeneous catalytic system that can be easily removed from reaction mixtures through simple filtration. It also exhibits excellent reusability, maintaining high catalytic activity and structural integrity over 10 catalytic cycles. Moreover, the methodology was successfully scaled up for the gram-scale synthesis of key compounds such as diisopropyl azodicarboxylate, methyl nicotinate, methyl cysteinate, and glucose pentaacetate, highlighting its practical viability.

Excess free radicals can have some negative effects on human health. In this paper, a nanozyme was successfully constructed by the coordination of copper ions and tannic acid, and its structure and elemental distribution were determined by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. Free radical scavenging experiments confirmed that it possessed superoxide dismutase-like activity, catalase-like activity, and hydroxyl radical scavenging ability. The results of thermogravimetric analysis experiments demonstrated that it possessed good thermal stability. A polyacrylonitrile hybrid nanofibrous membrane loaded with Cu/TA nanozyme was successfully constructed by electrospinning technology, and the maximum scavenging rate of DPPH and ABTS radicals can reach 64.22% and 58.44%, respectively. The nanofiber membrane also exhibited the ability to protect cells from oxidative stress damage. Therefore, the hybrid nanofibrous membrane has a broad application prospect in fields such as food preservation and biomedicine.

A rapid synthesis of a pH-stable magnetic nano-sensor (iron oxide nanoparticles, Fe-NPs, ∼2.6 nm) encapsulated with 3-aminobenzoic acid (3-ABA) was achieved. 3-ABA was prepared for the first time through the reduction of 3-nitrobenzoic acid (3-NBA) in the presence of HCl and tin. Electron-impact mass spectrometry (EIMS), Fourier-transform infrared (FTIR), nuclear magnetic resonance (NMR), ultraviolet visible (UV) spectroscopy and atomic force microscopy (AFM) were used for characterization. Ten drugs, namely, ciprofloxacin (CPF), levocetirizine (LCT), levofloxacin (LVF), sulbactam sodium (SBS), ephedrine (EPH), thymine (THM), sertraline (SRT), pyridoxine (PRX), cefotaxime (CFX) and ceftriaxone (CFT) were screened with Fe-NPs. A pronounced hypsochromic shift was observed for levofloxacin and ciprofloxacin, proving that 3-ABA-coated Fe-NPs were an efficient nano-sensor for levofloxacin and ciprofloxacin up to the limit of 0.5 and 0.7 μM, respectively. The stoichiometry of the complexes was conclusively determined as 1 : 1 using Job's plot analysis. Furthermore, the drugs were successfully detected in real samples, including tap water, well water, and human blood. Moreover, the antioxidant activity, urease and lipoxygenase inhibitory potential of these nanoparticles were evaluated, exhibiting promising antioxidant potential.

A global trend for the development of energetic materials using various sources is promoted by researchers annually. Solid bituminous hydrocarbons can play a key role in carbon science as abundant, low-cost, and mineral carbonaceous substrates. This study focuses on the design and synthesis of a series of new energetic materials from natural asphalt (NA), petroleum pitch (PP) and petroleum bitumen (PB) as industrial and available solid bituminous hydrocarbons. Energetic materials NA-NO₂, PP-NO₂ and PB-NO₂ were synthesized through the nitrification reaction. The heat of combustion, thermal behaviors and FTIR, elemental, BET, UV-vis, SEM, EDX-map, AFM, GC-MS and TG-DSC analyses were applied to identify and confirm that all were prepared successfully. Further, the physicochemical and energy properties of NA-NO₂, PP-NO₂ and PB-NO₂ were calculated using EMDB V 1.0 software. Thermal analysis showed thermal stability and insensitivity of NA-NO₂, PP-NO₂ and PB-NO₂ toward mechanical stimuli. The combustion heats of NA-NO₂, PP-NO₂ and PB-NO₂ were measured using a calorimeter bomb via the ASTM D240 method and evolved high amounts of energy of 23 500, 23 450 and 23 360 kJ kg⁻¹, respectively. The density of NA-NO₂ was measured using the ASTM-D8176 test and confirmed to be 0.5 g cm⁻³, which can be considered the lightest energetic material. Based on the conducted studies and analyses, new energetic materials synthesized based on solid bituminous hydrocarbons are classified as first-generation energetic materials.

Using theoretical and experimental tools we investigated the recognition of AAPH (2,2′-azobis(2-methylpropionamidine) dihydrochloride), a well-known water-soluble azo-compound employed as a source of peroxyl radicals, by cucurbit[6]uril (CB[6]), and cucurbit[8]uril (CB[8]). Density functional theory calculations and isothermal titration calorimetry experiments demonstrated that AAPH was not included in the cavity of CB[6], however, an exclusion complex was generated. Inclusion of AAPH in the CB[8] cavity was favored, forming stable inclusion complexes at 1 : 1 and 2 : 1 stoichiometries; AAPH@CB[8] and 2AAPH@CB[8], respectively. Radical formation upon photolytic cleavage of AAPH was examined theoretically, and by spin trapping with electron paramagnetic resonance. The radical yields detected with uncomplexed (free) AAPH and the AAPH-CB[6] (exclusion) complex were identical, whereas a marked decrease was shown for AAPH@CB[8]. Lower decreases were seen with a bimolecular (2 : 1) AAPH-CB[8] inclusion complex (2AAPH@CB[8]). This modulation was corroborated by the consumption of pyrogallol red (PGR), an oxidizable dye that does not associate with CB[6] or CB[8]. AAPH-CB[6] and 2AAPH@CB[8] did not significantly modify the initial consumption rate (Ri) of PGR, whereas AAPH@CB[8] decreased this. The oxidative consumption of free Trp, Gly–Trp and Trp–Gly by radicals derived from AAPH in the presence of CB[8] showed a dependence on the association of the targets with CB[8].

Chinese medicine has been widely studied owing to its many advantages. Baicalin (Bn), extracted from natural plants, has been shown to have significant anti-inflammatory and anticancer activity. Therefore, it is of great significance to develop a suitable method to detect the content of Bn in traditional Chinese medicine. Herein, we report an electrochemical sensor for the sensitive detection of Bn in Scutellaria root samples through a synergistic effect between upconversion nanoparticles (UCNPs) and three-dimensional macroporous graphene (3DG). The prepared UCNP-3DG composite was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction spectroscopy (XRD). This proposed sensor exhibited a low detection limit of 3.8 × 10⁻⁸ M (S/N = 3). Importantly, the established method possesses good stability and selectivity and can successfully detect Bn in Scutellaria root samples. It provides a suitable strategy for the determination of Bn and has potential application prospects in the assay of traditional Chinese medicine.

Hydrogel-based scaffolds play a crucial role in widespread biotechnological applications by providing physicochemical stability to loaded cells or therapeutic agents, interacting with organismal microenvironments, and controlling cargo release. Polysaccharides are regarded as attractive candidates among substrate materials because of their high water-retaining capacity, reactive functional groups, ease of gelation, low immunogenicity, biodegradability, and biocompatibility. However, employing polysaccharide-based hydrogel scaffolds for practical use in response to ongoing physiological and pathological changes within the human body, such as insufficient mechanical strength, uncertain degradation, and uncontrollable release patterns, is challenging. Several physically noncovalent or chemically covalent crosslinking strategies have been utilized to modify the physicochemical properties and biofunctionality of polysaccharide-based hydrogels. Among them, thermo-responsive gelation systems have been considered a promising approach for fabricating advanced scaffolds, referred to as ‘stimuli-responsive’ or ‘smart’ hydrogels. This is because of the sol–gel transition with a single trigger, requiring no further environmental or chemical intervention, and in situ and reversible gelation under ambient physiological temperature changes in a minimally invasive manner. This review highlights the classification, reaction mechanisms, characteristics, and advanced studies on thermo-responsive polysaccharides exploited in various biomedical fields.

Non-homogeneous ozone-catalyzed oxidation technology is one of the effective ways of treating wastewater, the core of which lies in the development of efficient ozone oxidation catalysts. This work proposes the design and synthesis of an efficient Cu/Mn/Ce multi-metal composite oxide catalyst by metal salt precursor mixing-direct granulation. The effect of metal doping on the catalyst properties was compared using Density function theory (DFT) calculations, and the Cu/Mn/Ce co-doping showed significant charge accumulation effect with a low ozonolysis energy barrier, which is more favorable for the generation of reactive oxygen species. The successful loading of the main active metal components, such as Mn, Cu, and Ce, was clarified by systematic characterization by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Brunauer–Emmett–Teller's test (BET), and the chemical oxygen demand (COD) removal could reach more than 60% for the simulated wastewater. The electron paramagnetic resonance (EPR) characterization clarified that the degradation of organic pollutants was mainly dominated by the combination of single-linear oxygen and superoxide radicals in the catalytic process, and the possible catalytic oxidation mechanism was proposed. This work advances the development of non-homogeneous ozone oxidation technology.