Here, the chitosan (CS) modified sepiolite (CS-Sep), chitosan quaternary ammonium salt (CAS) modified sepiolite (CAS-Sep), and CS with CSA comodified sepiolite (CS-CAS-Sep) were prepared and their adsorption performance for lead ions (Pb2+) from aqueous were well studied. All the prepared materials were well characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analyzer (TGA), and transmission electron microscopy (TEM). Meanwhile, the structural stability of CS-Sep, CAS-Sep, and CS-CAS-Sep, along with the impact of their crystal structures on adsorption efficiency, was also investigated through treatments at different calcination temperatures. The results revealed that the modified sepiolite presented superior adsorbability for Pb2+ compared to raw sepiolite. Especially composite materials CS-CAS-Sep showed excellent performance and the maximum adsorption efficiency for Pb2+ could reach 91.8% and with a maximum adsorption capacity 292.21 mu g/g. It is noted that the adsorption activity of these adsorbents significantly decreased when the calcination temperature exceeded 200 degrees C, which implies structural degradation of the materials. The study on isothermal adsorption behavior indicates that the adsorption of Pb2+ by modified sepiolite is mainly monolayer adsorption, and there is also chemical adsorption behavior.

Three crosslinked polyurethane copolymers were successfully synthesized as polymeric solid–solid phase change materials (SSPCMs) for thermal energy storage. These materials were fabricated utilizing trihydroxy compounds (glycerol, triethanolamine, and trimethylolethane) as chain extenders and polyethylene glycol (PEG) as the phase change functional segment. A comprehensive suite of characterization techniques was employed to investigate the chemical structures, thermal properties, and crystalline behaviors of the resulting SSPCMs. Fourier transform infrared (FTIR) spectroscopy confirmed the successful synthesis of the crosslinked polyurethane network. Polarizing optical microscopy (POM) and wide-angle X-ray diffraction (WAXD) analyses revealed that all three SSPCMs exhibit regular spherulitic morphologies with sharp diffraction peaks resembling those of pure PEG, although variations in spherulite size and diffraction intensity were observed among the samples. Differential scanning calorimetry (DSC) demonstrated the reversible latent heat storage and release capabilities of the synthesized SSPCMs, with a maximum endothermic enthalpy (ΔHendo) of 115.7 J/g. Furthermore, thermal cycling tests and thermogravimetric (TG) analysis verified their exhibit excellent reusability, thermal reliability, and high thermal stability.

Enamine is an important motif and widely studied in scaffold of natural product, medicinal chemistry and material science. Herein, a novel and environmentally friendly method to synthesize beta-enamino ketones in water from aryl disubstituted enones is described via C-Se bond cleavage under metal-free conditions. A series of easily available bioactive amines are also suitable for this reaction with good functional group tolerance and afford the excellent yield of expected product (up to 95 %). Furthermore, the synthetic utility of the developed protocol gives the innovative skeleton with N-halosuccinimides (NXS), offering insights into the production of valuable fluorine-containing pharmaceuticals and other biologically active compounds.

The synthesis of n-bromobutane from n-butanol is a classic undergraduate organic chemistry experiment, primarily intended to illustrate the bimolecular nucleophilic substitution (SN2) mechanism. However, this experiment is commonly plagued by low yields and the formation of byproducts (e.g., n-butene and di-n-butyl ether), which confuse students. To reveal the molecular origin of these competitive pathways, this study employs density functional theory (DFT) calculations to systematically investigate the reaction mechanism under acid catalysis. Four potential reaction pathways were explored: SN2 substitution, E2 elimination, intermolecular etherification, and a high-energy E2 pathway. The computational results indicate that the SN2 pathway to n-bromobutane is kinetically and thermodynamically favorable due to its low energy barrier. In contrast, the E2 elimination pathway possesses a higher energy barrier (18.8 kcal/mol vs. 13.5 kcal/mol for SN2), explaining why elevated temperatures favor the formation of n-butene. Moreover, the etherification pathway was found to be the most energetically demanding, consistent with the trace amounts of di-n-butyl ether observed experimentally. These findings provide a quantitative molecular-level rationale for the strict temperature control and standardized reagent addition sequences in the laboratory protocol. By visualizing the potential energy surfaces, this computational approach bridges the gap between theoretical mechanism and practical operation, offering a valuable pedagogical tool for enhancing student understanding.

Hydrate-based methods are a potential technique for methane storage, and the addition of deuterium oxide (D2O) may improve methane hydrate storage. In this work, methane hydrate formation in hydrogen oxide (H2O), deuterium oxide (D2O), and tritium oxide (T2O) was simulated using Gromacs software. The four-body structural order parameter (F 4), hydrate formation and growth, and total energy were analyzed. These results suggested that variations in both the F 4 value and total energy can be used to determine the formation of CH4 hydrates. The formation rate of CH4 hydrates in T2O was faster than that in D2O and H2O. For CH4 conversion at 2000 ns, (CH4 + D2O) is 1.70 times greater than that in (CH4 + H2O) hydrates. Based on both CH4 hydrate growth and CH4 conversion, (CH4 + D2O) hydrates are superior to (CH4 + H2O) hydrates for CH4 storage. (CH4 + T2O) hydrate is 2.25 times that of (CH4 + H2O) hydrates, which also offer useful insights for H2O/D2O separation and even nuclear wastewater treatment. In addition, the primary structure of CH4 hydrate in H2O, D2O, and T2O is of the SI type, with occasional occurrences of SII- and even SH-type hydrates. The presence of numerous unconventional hydrate cages may facilitate the formation of conventional hydrate cages.

The preparation of n-butyl ether is a classical organic chemistry teaching experiment but challenging for freshmen, as its reaction mechanisms and operational details are difficult to grasp. Developing new teaching content or approaches to help students fully understand the mechanisms and operational key points is highly desirable. Herein, Gaussian 09 was employed to systematically investigate the reaction mechanism of n-butyl ether synthesis, focusing on the main and side reaction pathways. Four pathways were evaluated, including the bimolecular nucleophilic substitution (SN2), bimolecular elimination reaction (E2), unimolecular nucleophilic substitution (SN1), and unimolecular elimination reaction (E1). The results indicate that the pathway of n-butanol undergoing SN2 substitution to form ether is the dominant reaction channel under acid catalysis. For E2 elimination mechanism, the transition state energy barrier is higher than that of the SN2 pathway. Which indicated that alkene product could appeared under high-temperature or prolonged reaction conditions. The SN1 substitution mechanism also has a higher transition state energy barrier than the SN2 pathway. In the SN1 pathway, the generated carbocation exhibits relatively high energy, and thus tends to form alkene products in subsequent steps. These findings highlight that controlling the temperature at an appropriate level is crucial for the experiment of n-butyl ether preparation. Additionally, the transition state energy barrier of the E1 elimination mechanism is lower than that of the E2 pathway, indicating that intramolecular dehydration in this system primarily proceeds via the E1 mechanism. This work utilizes computational chemistry to intuitively and quantitatively illustrate the competitive mechanisms between ether and alkene formation from n-butanol in a graphical format. Which will facilitate student better understanding of the reaction mechanism of this experiment and provide valuable supplementary material for experimental teaching.

Plant-derived activated carbons (PACs) are promising and sustainable adsorbents for heavy metal removal but lack standardized classification frameworks on raw material selection. Inspired by the International Code of Botanical Nomenclature (ICBN), herein we systematically evaluated Ni(II) adsorption by leaf and stem-derived PACs from eight plant species collected in Chenzhou, China. The PACs were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, and scanning electron microscopy (SEM). Results showed that ICBN-based classification effectively revealed taxonomic and organ-specific differences in adsorption performance. Leaf-derived PACs from six plant species (Prunus serrulata Lindl, Trachycarpus fortunei, Acer palmatum, Alternanthera sessilis, Setcreasea purpurea, and Prunus persica) exhibited superior Ni(II) adsorption compared with their stem-derived counterparts. In contrast, stem-derived PACs of Dicranopteris pedata and Jasminum nudiflorum Lindl outperformed their leaf-derived equivalents. Among these materials, stem-derived PACs from Dicranopteris pedata had the largest specific surface area (598.2 m²/g) and the highest Ni(II) adsorption capacity (62.2 mg/g at 25 ℃). Further analysis revealed that specific surface area, micropore development, and porous morphology, regulated by plant taxonomic traits and organ structure, were key factors governing adsorption efficiency. Adsorption kinetics and isotherms suggested a multi-step process involving both physisorption and chemisorption, with chemisorption as the dominant mechanism. Equilibrium data were well described by the Langmuir model, indicating monolayer adsorption. This study establishes an ICBN-inspired standardized approach for plant raw material selection, providing a critical experimental basis for developing high-performance PACs for Ni(II) adsorption.

表面化学在电化学、多相催化等领域具有重要应用价值.由Hammer和Nørskov教授提出的D带中心理论作为该领域的代表性成果,早期被广泛用于预测吸附强度.该理论认为,材料的D带中心值(εd)能级越低,其吸附能力越弱.然而,随着研究的深入,该理论在预测精度方面逐渐显现出局限性,特别是在解释小颗粒金属体系和复杂多金属体系的吸附行为时,出现了反常现象.此外,该理论未充分考虑吸附位点和吸附质特性等因素,而实际上,表面活性位点的差异和吸附质自旋多重态都会显著影响吸附能.尽管2013年Nørskov教授团队通过引入D带宽度Wd对理论进行了改进,但预测效果仍不理想.2018年,随着Lobster软件的开发,晶体轨道哈密顿布居(COHP)理论得到广泛应用,但其精度仍有待提高,且积分COHP(ICOHP)描述符的物理意义尚不明确.因此,亟待寻求新的、更为完善的理论来描述表面吸附强度. 针对这一问题,北京化工大学曹达鹏团队近期提出了一种新的成键与反键轨道稳定电子布居差理论(BASED),该理论不仅可以成功地解释D带中心理论的异常现象,在预测活性位点上中间体的吸附能和键长时,也表现出更高的准确性.同时,基于BASED理论,观察到吸附过程中自旋过渡态的一种新现象:当活性中心原子与中间体的距离接近2.5 Å时,系统通常会形成不稳定的高自旋过渡态,而这种状态能够显著增强活性中心对中间体的吸附能力. 综上所述,该论文系统阐释了D带中心理论存在的反常现象,并创新性地提出BASED理论用于评估表面吸附强度.研究发现,D带中心理论出现反常现象的根本原因在于:其仅考虑了轨道能级位置(εd),却忽略了成键电子数的影响,且未充分考虑吸附后费米能级处需形成成键轨道这一关键因素.相比之下,BASED理论在吸附能和键长预测方面展现出更高的精度,不仅为开发新一代量化计算软件的开发奠定了重要理论基础,更为深入理解表面催化过程提供了全新的物理视角.这一理论突破对表面化学研究具有重要指导意义.

Organic chemistry is an important basic course in the field of natural science, and its experimental teaching is also an important part of this course. How can students acquire practical ability in experimental practice within the limited class hours? Our organic chemistry experimental teaching team has developed a teaching model using density functional theory (DFT) calculation-aided experimental teaching of organic chemistry. In this paper, taking the ethyl acetate synthesis experiment as an example, we provided a case study using DFT calculation-aided experimental teaching of organic chemistry. The reaction mechanism of ethyl acetate was studied using Gaussian 09 software. The changes in reaction energy barrier and carbonyl carbon structure were also studied. Our results show that the rate-determining step is the nucleophilic addition. The reasonable raw material addition procedure is that the glacial acetic acid and anhydrous ethanol should first be added to a flask, followed by adding sulfuric acid slowly. DFT calculation can explain clearly the mechanism of esterification reaction in a graphic form, which is not only helpful for the students to better grasp the key points of the experiment but also beneficial for deeply understanding the esterification reaction. It provides some important guidance and reference for the teaching activities of organic chemistry in the university and high school.

In this paper, we describe an operationally facile and generally applicable intermolecular dehydrative Friedel-Crafts reaction for aliphatic alcohols via Re2O7 catalysis in hexafluoroisopropanol (HFIP). This method obviates the need for highly corrosive Brønsted acids or strong Lewis acids; therefore, it is convenient to perform and offers improved functional group tolerance. DFT calculations suggested that the hydrogen-bonding interactions between HFIP and the perrhenate moiety significantly lowered the energetic barrier for catalytic C-O bond cleavage in aliphatic alcohols.

The advancement of integrated circuits has made it easier to reduce the size of increasingly potent wearable electronic devices. However, it is still difficult to seamlessly integrate electronic systems enabling unrestricted human behavior into wearable gadgets. The procedure of creating fiber devices by twisting fiber electrodes and incorporating them into textile systems is exhibited in recent work. These textile systems are highly resilient and flexible, which makes them ideal for various wearable applications, i.e., thread lithium-ion batteries (TLIBs), multi-ply sensing threads (MSTs), and thread electroluminescent devices (TELDs).

Hydrate-based gas storage technology is a novel and promising method for gas storage and transport, with key features like compact storage, benign process, easy gas recovery, non-explosive, mild storage conditions and robustness against impurities. The slow formation kinetics, high compression and refrigeration cost, and longterm storage stability were the major challenges and concerns. This review provides a comprehensive overview of the development of hydrate-based method for gas storage, mainly focusing on the hydrate formation and storage steps. Strategies to shift hydrate equilibrium toward milder conditions, enhance hydrate formation kinetics and improve hydrate storage stability are discussed. Highlights of recent trends include the employment of greener, safer and more efficient promoters like amino acids, the ultra-rapid formation and breakthrough gas uptake achieved by synergistic effect of thermodynamic and kinetic promoters, and the shift of self-preservation effect to temperatures above 273.2 K. Some challenges still exist, such as the relatively high volatility of the organic promoters, the additional material cost associated with the use of promoters and the uncertainty of selfpreservation effect for long-term and large-scale storage. Some prospective research directions of the hydratebased gas storage technology could be to develop greener and more effective promoters, evaluate the value chain based on sII hydrates, and explore its potentials in some specific applications such as long-term stationary gas storage.

The current study involved the preparation of a number of MnOx/Sep catalysts using the impregnation (MnOx/Sep-I), hydrothermal (MnOx/Sep-H), and precipitation (MnOx/Sep-P) methods. The MnOx/Sep catalysts that were produced were examined for their ability to catalytically oxidize formaldehyde (HCHO). Through the use of several technologies, including N2 adsorption–desorption, XRD, FTIR, TEM, H2-TPR, O2-TPD, CO2-TPD, and XPS, the function of MnOx in HCHO elimination was examined. The MnOx/Sep-H combination was shown to have superior catalytic activities, outstanding cycle stability, and long-term activity. It was also able to perform complete HCHO conversion at 85 °C with a high GHSV of 6000 mL/(g·h) and 50% humidity. Large specific surface area and pore size, a widely dispersed active component, a high percentage of Mn3+ species, and lattice oxygen concentration all suggested a potential reaction route for HCHO oxidation. This research produced a low-cost, highly effective catalyst for HCHO purification in indoor or industrial air environments.

In this paper, we describe a Re2O7-mediated ring-opening arylation of unactivated arylcyclopropane because of its functionalization with various arenes via Friedel-Crafts-type reactivity. This protocol allows facile access to functionalized 1,1-diaryl alkanes and is characterized by a broad substrate scope, mild reaction conditions, high efficiency, and high atom economy. Both density functional theory calculations and deuterium labeling experiments were carried out to justify the indispensable role of HFIP in this transformation and pointed to Re2O7-mediated ring opening being the rate-determining step.

Alcohols are widely available and can be derived from renewable resources. Catalytic alcohol amination for N-alky amine synthesis using the borrowing hydrogen strategy is an environmentally benign and prominent sustainable method, which produces water as the sole byproduct. However, expensive noble metals are generally employed for this transformation, while the nonprecious metal-based catalysts were also known for this reaction and have attracted considerable attention recently. Herein, an efficient N-alkylation of amines with alcohols using base-metal cobalt catalysts is reported. This reaction is catalyzed by an N-heterocyclic carbene cobalt-pincer catalyst and the reaction operates simply and under mild conditions. Various alcohol and aniline substrates and functional groups including nitrile, ether, thioether and alkene could be well tolerated. Moreover, experimental studies and DFT calculations were also performed to illustrate the reaction mechanism. Our results suggest that the N-alkylation reaction proceeds via a hydrogen autotransfer mechanism.

In this paper, we describe a Re2O7-mediated ring-opening arylation of unactivated arylcyclopropane because of its functionalization with various arenes via Friedel–Crafts-type reactivity. This protocol allows facile access to functionalized 1,1-diaryl alkanes and is characterized by a broad substrate scope, mild reaction conditions, high efficiency, and high atom economy. Both density functional theory calculations and deuterium labeling experiments were carried out to justify the indispensable role of HFIP in this transformation and pointed to Re2O7-mediated ring opening being the rate-determining step.

Two new Schiff‐base bismuth (III) complexes were prepared by an equivalent reaction between Schiff‐base ligand and Bi (NO3)3•5H2O with the assistance of Mannitol. The chemical structures of the two complexes were characterized by spectroscopic studies (FT‐IR, NMR, and MS), elemental analysis, and single‐crystal X‐ray diffraction. The ligand‐to‐metal ion ratio was found to be 1:1 in the complexes. During the formation of the complexes, Schiff bases changed from the amidic forms to the iminol forms, and the resulting tautomers could coordinate with bismuth (III) ions to produce dinuclear BiIII complexes(1a and 2a). Structural analyses showed that each Bi (III) ion held a distorted capped octahedron geometry with a seven‐coordinate mode in two complexes. Screening in vitro biological activities revealed that two bismuth (III) complexes exhibited much higher antimicrobial and cytotoxic activity than their parent ligands. The cytotoxic activity of the complex(1a) was close to that of the known anticancer drug (Doxorubicin) by evaluating against SGC7901 cells, with the IC50 value 0.59 μM. The complex(1a) could effectively induce SGC7901 cell apoptosis and its oral acute toxicity for LD50 value was found to be 576 mg kg−1. The content of bismuth (III) in mitochondria was higher than that in the nucleus.

The removal of nitrogen trifluoride (NF3) is of significant importance in atmospheric chemistry, as NF3 is an important anthropogenic greenhouse gas. However, the radical species OH and O(1D) in atmospheric conditions are nonreactive towards NF3. It is necessary to explore possible ways to remove NF3 in atmosphere. Therefore, the participation of water molecules in the reaction of NF3 with OH was discussed, as water is abundant in the atmosphere and can form very stable complexes due to its ability to act as both a hydrogen bond donor and acceptor. Systemic DFT calculations carried out at the CBS-QB3 and ωB97XD/aug-cc-pVTZ level of theory suggest that water molecules could affect the NF3 + OH reaction as well. The energy barrier of the SN2 mechanism was decreased by 8.52 kcal/mol and 10.58 kcal/mol with the assistance of H2O and (H2O)2, respectively. Moreover, the presence of (H2O)2 not only reduced the energy barrier of the reaction, but also changed the product channels, i.e., formation of NF2O + (H2O)2-HF instead of NF2OH + (H2O)2-F. Therefore, the removal of NF3 by reaction with OH is possible in the presence of water molecules. The results presented in this study should provide useful information on the atmospheric chemistry of NF3.

Unreactive C-H bond activation is a new horizon for frustrated Lewis pair (FLP) chemistry. This study provides a systematic assessment of the catalytic reactivity of recently reported intra-molecular FLPs on the activation of typical inert C-H bonds, including 1-methylpyrrole, methane, benzyl, propylene, and benzene, in terms of density functional theory (DFT) calculations. The reactivity of FLPs is evaluated according to the calculated reaction thermodynamic and energy barriers of C-H bond activation processes in the framework of concerted C-H activation mechanisms. As for 1-methylpyrrole, 14 types of N-B-based and 15 types of P-B-based FLPs are proposed to be active. Although none of the evaluated FLPs are able to catalyze the C-H activation of methane, benzyl, or propylene, four types of N-B-based FLPs are suggested to be capable of catalyzing the activation of benzene. Moreover, the influence of the strength of Lewis acid (LA) and Lewis base (LB), and the differences between the influences of LA and LB on the catalytic reactivity of FLPs, are also discussed briefly. This systematic assessment of the catalytic activity of FLPs should provide valuable guidelines to aid the development of efficient FLP-based metal-free catalysts for C-H bond activation.