Wavefunction and reactivity study of benzo[a]pyrene diol epoxide and its enantiomeric forms

Humic Acid with Vertical Adsorption Conformation Enhanced the Transport of Petroleum Hydrocarbon-Contaminated Colloids

Humic acid (HA) enhances colloidal transport in porous media, yet the mechanisms by which the HA adsorption conformation affects colloid transport remain unclear. This study investigated the influence of HA on the transport of petroleum-hydrocarbon-contaminated soil colloids (TPHs-SC) in saturated sand columns. The presence of TPHs on the colloidal surface occupied adsorption sites, hindering HA from forming a horizontal adsorption conformation, as observed on uncontaminated soil colloids (SC). Instead, a vertical adsorption conformation was formed, reducing the overall adsorption of HA. Vertically adsorbed HA increased the colloidal diffuse double-layer potential and extended the Derjaguin-Landau-Verwey-Overbeek energies between colloids and water-bearing media. This was evidenced by higher ζ potentials (-28.5 to -34.0 mV) and enhanced TPHs-SC transport compared to SC (ζ potentials ranging from -25.2 to -29.5 mV) in the presence of HA, particularly under alkaline conditions. Additionally, weak van der Waals and electrostatic interactions between TPHs near colloidal surfaces and free HA/TPHs formed a zonal distribution, facilitating the cotransport of colloids with TPHs. These findings underscore the significance of the HA adsorption conformation in TPHs-SC transport and provide insights into the critical mechanisms from an environmental structural chemistry perspective.

Interface-Confined Catalytic Synthesis of Anisotropic Covalent Organic Framework Nanofilm for Ultrafast Molecular Sieving

Covalent organic frameworks (COFs) have emerged as prominent membrane materials for efficiently fractionating organic molecules and ions due to their unique pore structure. However, the fabrication of free-standing COF nanofilms with high crystallinity remains an arduous undertaking, and feasible methods that can enable precise control over the film microstructure are barely reported. This work conceives an exquisite interface-confined catalytic strategy to prepare Tp-BD(OH)2 COF nanofilm with an anisotropic structure analogously to conventional polymeric membranes. Experimental data and molecular simulations reveal that the hydroxyl groups on the framework substantially capture and anchor the acid catalyst through hydrogen bonding interactions at the incipient stage of interfacial polycondensation, instigating confined catalysis and self-termination reaction at the interface. The distinctive asymmetric structure endows the Tp-BD(OH)2 COF nanofilm with a record-breaking pure water permeance of 525.3 L m-2 h-1 bar-1 and unprecedented dye/salt selectivity of 648.6, surpassing other reported COF films and state-of-the-art nanofiltration membranes, as well as enduring structural durability and chemical stability. The implemented interface-confined catalysis strategy opens up a new avenue for regulating the COF nanofilm microstructure and holds broad prospects for the rational design of high-performance membranes for sustainable water purification and treatment.

Recyclable magnetic composites prepared by a novel reverse encapsulation reaction to increase benzene rings reactive sites for enhanced removal of 3,4-diaminotoluene: Theoretical prediction with experimental statistics

The widespread distribution of organic amine reagent in the aquatic environment has severely constrained ecological health, and mitigating its potential environmental hazards is imperative. Herein, the recyclable magnetic composite (Fe3O4-3-Amino-Tereph-acid) with abundant homogenous reaction sites and excellent removal efficacy (34.72 mg/g) towards 3,4-diaminotoluene (UENE) contaminant was fabricated via the reverse direction layer-by-layer reaction. This reaction method greatly solved the difficulty of the newly introduced reaction sites being limited by the traditional grafting reactions methods. The effectiveness of the reverse direction layer-by-layer reaction was proved via multiple characterization techniques. More importantly, the necessity of the reverse direction layer-by-layer reaction, the occupation preference of reaction active sites and the removal pathway of contaminant molecules in complex removal reaction systems were studied from the DFT calculations prediction perspectives. Furthermore, the environmental behaviours of Fe3O4-3-Amino-Tereph-acid towards UENE in different environmental systems were comprehensively studied, contributing to comprehending the capturing process existing in liquid-solid phases. Overall, multiple driving forces, microscopic and macroscopic forces were mutually involved in the complex chemisorption reaction. The possible environmental application prospects of Fe3O4-3-Amino-Tereph-acid were discussed via the Requirement-Difficulty-Methodology-Extend framework. This work proposed a feasible strategy to massively increase the reactive active sites on the surface of magnetic composite, which could greatly facilitate its environmental applications, especially in eliminating organic amine contaminants fields, and theoretical prediction deeply assessed the underlying microscopic bonding modes and mechanisms in environmental systems.

Mechanism of High Hydrocarbon-Fuel-Gelation Performance of Ultralow-Concentration Bis-urea-Based Gellants

Bis-urea-based gellants have garnered considerable attention due to their capacity to form all kinds of gels in solvents for multiple applications. Nevertheless, the range of applicable solvents is limited, and the synthesis process is complicated. Herein, we report a one-step synthesis process of bis-urea-based gellants (Bu(n)) for gelling nonpolar organic solvents, including high-energy fuels. Importantly, the critical gelation concentration (CGC) of Bu(n) decreases with the increase of alkyl chain length, and that of Bu18 is lower than 0.1 wt % in various hydrocarbon fuels. The discrepant gelation performance of gellants in solvents was investigated by molecular dynamics simulation and spectral characterizations. The results indicate that the electrostatic interaction between urea groups is vital to constructing a gellant framework, and the wide van der Waals (vdW) surface provided by alkyl groups helps to immobilize solvents. The nonbonding interactions between gellant molecules facilitate the formation of a 3D fibrous network structure, which further accumulates into a cambium layer structure. Due to the excellent gelation performance of gellants in fuels, the gel fuels perform the rheological characteristics of shear thinning and thixotropic recovering with calorific value remaining, thus demonstrating potential for application.

Dinitramide salts based on nitropyrazole-diaminotriazole hybrid: novel ionic energetic materials with high-energy and low-sensitivity

In this study, employing a simple anion exchange strategy and straightforward three-step synthetic route, a pair of promising nitrogen-rich heterocyclic cation and oxygen-rich anion were assembled together to generate two novel dinitramide energetic salts, both of which exhibit prominent detonation performance comparable to benchmark explosive RDX while possessing significantly lower mechanical sensitivity than RDX, thereby highlighting them as promising candidates for advanced secondary explosives. This work has directly led to a practical protocol for the design of chloride-free environmentally friendly IEMs, and accelerates the development of organic explosives with high-energy and low-sensitivity.

Effects of microwave energy transfer on release and degradation of anthocyanins in berry puree

To elucidate the distinctive effects of microwave energy on the anthocyanins content in berry puree, comparative experiments and simulation analysis of essentially heating modes are introduced via radiation (microwave), convective and conductive. Microwave energy has the strongest action on anthocyanins state due to uniform generation of in situ heating through entire volume of berry puree. Microwave heating may promote the release or hinder the degradation of anthocyanins as variable polar response and reaction barrier of anthocyanins depending on electric field direction with the unsymmetrical structure in polar molecules. The intermolecular force (hydrogen bond, van der Waals force etc.) may be broken in berry puree to form order arrangements of anthocyanins till tolerance temperature 80 °C under microwave heating. The optimal parameters of microwave heating are developed as microwave intensity of 30 W·g-1 and temperature of 50 °C to achieve the highest anthocyanins retention till target moisture less than 0.5 (d.b.).

Calixarene-Based Magnetic Nanosponge Decorating AgNPs for Rapid and Selective Surface-Enhanced Raman Scattering Analysis in Complex Samples

Rapid and accurate analysis of trace targets in complex samples remains an enormous challenge. Herein, the calix[x]arene-based magnetic cross-linked polymer decorating AgNPs, abbreviated Fe3O4-CXA-DAB@AgNPs nanosponge, was developed for fast surface-enhanced Raman scattering (SERS) analysis in complex samples. The Fe3O4-CXA-DAB@AgNPs nanosponge surface was constructed by high-density CXA units with special cavity size and structure, which could selectively recognize and enrich targets to the sensing surface by the host-guest effect and molecule interactions. The Fe3O4-C4A-DAB@AgNPs showed significant SERS enhancement to choline chloride (ChCl) and succinylcholine chloride (SCC) with an enhancement factor (EF) of 2.9 × 107 and 6.3 × 106, respectively. The Fe3O4-C6A-DAB@AgNPs exhibited high SERS activity to thiabendazole with an EF of 7.6 × 106. Introducing recognition-enrichment-separation with SERS sensing, the nanosponge could achieve rapid enrichment sensing of targets within 6-8 min. Also, the Fe3O4-CXA-DAB@AgNPs nanosponge exhibited good stability for rapid detection with relative standard deviations less than 6.3% for intra-batch (n = 25) and 6.8% for inter-batch (n = 15). Benefiting from these merits, the Fe3O4-C4A-DAB@AgNPs was employed for fast SERS analysis of ChCl and SCC in real samples. The limits of detection were 0.62 μg/L for ChCl and 2.0 μg/L for SCC. ChCl was found in feed sample with recoveries of 85.3-108%, and SCC was found in serum samples with recoveries of 85.7-111%. The methods provided a significant reference for the selective analysis of targets by regulating the calix[x]arenes cavity size to satisfy different molecules and rapid quantification strategy by integrating sample pretreatment technology with sensing detection all-in-one.

Determine the Relative Aromaticity of Bilayer Graphyne, Bilayer Graphdiyne, and Bilayer Graphtriyne

The electronic structure characteristics of bilayer graphyne, bilayer graphdiyne, and bilayer graphtriyne were systematically studied using molecular orbital (MO) analysis, density of states (DOS), and interaction region indicator (IRI) methods. The delocalization characteristics of the out-of-plane and in-plane π electrons (i.e., πout and πin electrons) of these materials were analyzed using the localized orbital locator (LOL). In addition, their responses to external magnetic fields were investigated through anisotropic induced current density (AICD) and isoscalar chemical shielding surfaces (ICSSs) to compare the induced ring currents and magnetic shielding effects, further exploring the aromaticity of the three bilayer materials. The research results indicate that as the number of alkyne groups increases, the aromaticity of the bilayer graphyne structure gradually weakens. Finally, their photophysical properties were studied through TD-DFT calculations. The results show that they exhibit strong localized excitation characteristics.

Molecularly imprinted polymer gel with superior recognition and adsorption capacity for amphenicol antibiotics in food matrices

A molecular-imprinted polymer (MIP) gel with high effective recognition of amphenicol antibiotics was synthesized for the first time based on layered double hydroxide (LDH) as the support and initiator, and functionalized β-cyclodextrin (β-CD) as the functional monomer. The synergistic effect of molecular imprinting recognition and β-CD host-guest affinity enabled MIP gel to exhibit excellent selectivity (imprinted factors: 3.9-9.4) and high adsorption capacity (28.9-75.4 mg g-1) for amphenicol antibiotics. Different adsorption isotherms and kinetics models were followed, suggesting heterogeneous single-layer recognition and chemical adsorption. After 5 cycles of adsorption and desorption, the adsorption capacity of MIP gel retained above 83.6 %, demonstrating favorable reproducibility and stability. Under optimal conditions, the method validation showed a satisfactory limit of detection (5-10 μg L-1), good correlation (r2 > 0.9967), and respectable recovery (82.6-105.3 %). The MIP gel was applied to extract amphenicol antibiotics from food matrices, achieving recoveries in the range of 78.3-104.5 %. Importantly, the recognition mechanism was studied in detail using density functional theory. Therefore, the established method demonstrates high sensitivity and can be applied as a new tactic for detecting amphenicol antibiotics in food matrices.

Investigating the interaction mechanisms between arachin and resveratrol: Utilizing multi-spectroscopy and computational chemistry

Arachin (ARA) and resveratrol (RES) are the primary protein and bioactive compound in peanuts and their processed products. However, the mechanism of interaction between these two substances remained unclear. To investigate protein structural changes, conformational variations, and molecular mechanisms in the interaction between them, multispectral analysis and computational chemistry methods were employed. Experimental results confirmed that RES quenched ARA's intrinsic fluorescence through static quenching, indicating their interaction. Thermodynamic analysis revealed the interaction between them was endothermic, spontaneous, and primarily hydrophobic. Molecular dynamics (MD) simulations highlighted strong affinity between RES and ARA, with key amino acids (His425, Val426, Phe405, and Phe464) facilitating their interaction. RES binding increased stability without significant protein conformational changes. The independent gradient model based on Hirshfeld partition (IGMH) validated their interaction, emphasizing van der Waals (VDW) interactions and hydrogen bonds (H-bonds) as crucial for stable binding. This research lays a theoretical foundation for potential applications of ARA-RES complex products in the food industry.

Unveiling the Preference for a Carbon Spacer Length of Three in Zwitterionic Sulfobetaines: Insights from DFT Calculations

Zwitterionic sulfobetaines (SBs) have shown excellent performance in biological and chemical applications. The carbon spacer lengths (CSLs) between oppositely charged groups are crucial for the properties of SBs. However, most reported studies naturally selected the SB molecule with a CSL of three, although the underlying reason for this choice remains unclear. In this work, using DFT calculations, we systemically investigated the effect of CSL on the molecular properties of SB molecules, including optimized confirmations, electrostatic potentials, atomic charges, dipole moments, and their self-association behaviors in both the gas phase and water solvent. The solvation free energies of SB molecules with various CSLs were calculated to evaluate the hydrophilicity of SBs. The results of our calculations demonstrated that a CSL of three is a critical length for optimal molecular properties, offering the strongest charge separation and the best hydrophilicity. While all SB molecules can form stable dimers through strong intermolecular electrostatic interactions, the dimers become unstable in water due to electrostatic shielding by water molecules. These findings shed light on the preference for a CSL of three in zwitterionic SBs and provide guidance for the rational design of SB-based materials.

Superior Capacitive Energy Storage at High Temperature of All-Organic Aromatic Polymer via Enhancing Conjugate Angle between Benzene Rings

High-temperature polymer capacitors with superior energy storage density are considerable and desirable components in advanced power pulse, electrical, and energy conversion systems. However, due to the π-π conjugated benzene ring structure, carriers migrate through polyimide (PI) chains, reducing discharge energy density (Ue) and charge-discharge efficiency (η) at high temperature. Here, the ether (-O-) and isopropylidene (-C(CH3)2-) groups are purposefully introduced into the position between the benzene rings to increase the conjugate angle in PI chains, and spatial folded chains are designed to impede charge transport at high temperature. The experimental results show both surface charge dissipation rate and leakage current decrease at 150 °C when (-C(CH3)2-) groups increase, indicating that deep traps that hinder charge transport are introduced in the chains. Hence, the breakdown strength of the designed polymer (BAPP+BPADA) significantly increases, and its Ue and η reach 3.87 J/cm3 and 90% at 150 °C, 2.74-times the energy density of the pristine PI film. Simultaneously, the BAPP+BPADA film exhibits excellent discharge response and cycling charge-discharge stability, which have the potential to be applied in functional devices under extreme conditions. The work performs a superior energy storage all-organic film and offers a strategy that regulates the chains' spatial topological structure for future aromatic polymers for high-temperature energy storage.

Effects of Cosolvent and Nonsolvating Solvent on the Structural Dynamics of Organic Electrolytes in Sodium-Ion Batteries

In sodium-ion batteries (SIBs), the performance of a single solvent often does not meet actual requirements and a cosolvent or nonsolvating solvent is needed. However, the effect of these electrolyte additives on the solvation structure and dynamics of Na+ in SIBs is yet to be fully understood. Herein, electrolyte structural dynamics are examined for NaPF6 in dimethyl carbonate (DMC) with 1,1,2,2-tetrafluoro-2,2,2-trifluoroethoxy ethane (HFE) as the nonsolvating solvent or propylene carbonate (PC) as the cosolvent using steady-state and time-resolved infrared (IR) spectroscopies. Molecular dynamics simulations show that the solvation size of Na+ decreases with a loosened structure upon adding the nonsolvating solvent, whereas its first solvation shell becomes denser and the second one becomes softened with decreased participation of the PF6- anion upon adding the cosolvent. While a decreased participation of DMC in the solvation layer of Na+ is suggested by linear IR results, an increased structural inhomogeneity (and hence overall more dynamical fluctuations) is found for Na+-coordinated DMC upon adding both additives by two-dimensional (2D) IR spectroscopy where the carbonyl stretch is used as a probe. The Na+/DMC/PC complex is found to structurally evolve slower than both Na+/DMC and Na+/DMC/HFE complexes on the picosecond time scales by spectral diffusion dynamics extracted from 2D IR diagonal signals. Frontier orbital theory calculations also indicate that both solvent additives are beneficial to increasing the stability of PF6-. The results obtained in this work provide important insights into the roles played by the solvent additives in influencing the solvation structures and dynamics of Na+, which are critical for understanding the Na+ transfer mechanism in SIBs.

In situ self-cleaning removal of emerging organic contaminants with covalent organic framework armed with arylbiguanide

An in situ self-cleaning covalent organic framework featuring arylbiguanide arms (Aryl-BIG-COF) was first developed to remove emerging organic pollutants such as propranolol (PRO) from water. The main breakthroughs addressed the scarcity of functional active sites, the impracticality of ex situ regeneration, and the rapid recombination of electronhole pairs in the application of COFs. Owing to the directional capture ability and electronic structure regulation of the arylbiguanide arms, the adsorption capacity and photocatalytic degradation rate of the newly synthesized COF increased by nearly four and seven times, respectively. Its self-cleaning ability, driven by the photocatalytic regeneration of active sites, enabled in situ removal of PRO and sustained over 90 % removal efficiency after six cycles. Moreover, it demonstrated broad applicability for removing PRO and other emerging pollutants, such as bisphenol A (BPA), tetracycline (TC), and norfloxacin (NOR), across various water matrices with less residual toxicity. The coexisting organic matter and ions in natural water promoted the removal of PRO. The enhancement mechanism involved arylbiguanide arms narrowing the band gap and inducing local charge polarization, thereby increasing the separation efficiency of electronhole pairs. This work provides significant insights into the structural design and practical applications of COFs for purifying water.

A short-time, low-dosage chemicals dyeing of polyester/cotton blended fabric with benzothiazole dyes in water-less, salt-free dyeing system

Non-aqueous media dyeing technology has highly innovative as it reduces pollution without increasing cost in polyester/cotton blended fabric dyeing. However, disperse dyes can stain in cotton component of the polyester/cotton blended fabric during dyeing process, resulting poor quality of dyed products. In this study, a groundbreaking comprehensive investigation was conducted on the dyeing behavior of C.I. Disperse Red 177 and C.I. Disperse Red 145 in non-aqueous media. The results revealed that the dyes' uptake rates on polyester components in non-aqueous medium were comparable to those in traditional water dyeing baths. Conversely, the staining rate of disperse dye on cotton fiber surface was relatively high. Interestingly, the migration of dyes from polyester surface to cotton surface after dyeing had minimal impact on staining. Thermodynamic analysis in non-aqueous media showed that the Gibbs free energy of C.I. Disperse Red 145 adsorption on cotton was higher than that of C.I. Disperse Red 177. Computational chemistry simulations showed that the terminal group of C.I. Disperse Red 177 (N-acetoxyethyl) led to stronger electrostatic interaction with cotton compared to C.I. Disperse Red 145. Therefore, disperse dyes with N-ethyl end groups have a weak interaction with the cotton and stain less on the cotton fiber surface.

Identification of fenfluramine adulteration in slimming foods using a highly sensitive immunoassay

Fenfluramine, an appetite suppressant used for weight loss, can cause significant harm if overdosed. The unauthorized addition of fenfluramine to slimming foods has raised concerns. Currently, no rapid screening method is available for the quick detection of fenfluramine in the field. This study proposes six new haptens with varying spacer arm lengths and hydrophobicity, promising to elicit antibodies capable of being highly specific and strongly binding to fenfluramine. The study found that highly hydrophobic haptens with long spacer arms favored the generation of highly sensitive antibodies. Key interaction forces for antibody recognition of fenfluramine were revealed by intrinsic molecular mechanisms. Based on the above results, monoclonal antibody for fenfluramine was prepared and an ultrasensitive icELISA method with heterologous coating strategies was developed in slimming foods. The IC50 of the method was 6.25 ng/mL, the linear detection range was 0.47-83.51 ng/mL and the detection limit was 0.10 ng/mL. Recovery rates in tea bags, tablets, capsules, coffee, and beverages ranged from 96.56 % to 108.90 %. The method was successfully applied to blind samples, showing strong correlation with HPLC-MS/MS results. Thus, the developed method is suitable for identifying fenfluramine adulteration in slimming foods.

Investigating a Seemingly Simple Imine-Linked Covalent Organic Framework Structure

The structures of covalent organic frameworks (COFs) are typically determined through modeling based on powder X-ray diffraction. However, the intrinsically limited crystallinity of COFs often results in structural determinations of low fidelity. Here, we present real-space imaging of an extensively studied two-dimensional imine-based COF. Contrary to the conventional understanding that this COF features uniform hexagonal pores, our observations reveal the presence of two distinct sets of pores with differences in shape and size. Motivated by this finding, we conducted reciprocal-space characterizations, complemented by solid-state nuclear magnetic resonance spectroscopy and density functional theory calculations, to reevaluate this seemingly simple structure. The collective results allow for the establishment of a new structural model for this landmark COF and its derivatives, differing from the conventional model in both intra- and interlayer configurations. Furthermore, we identified various previously unrecognized defective structures through real-space imaging, which have significant implications for COF applications in separation and catalysis. Our study demonstrates the complexity and heterogeneity of COF structures, while also highlighting the imperative for structural reevaluation using advanced characterization techniques.

Analysis of Interaction Features of Cyclo[13]carbon with Small Molecules and Formation Mechanism of Its Dimer

The newly discovered cyclo[13]carbon, the first artificially synthesized odd-numbered carbon ring, is an intriguing carbon isomer that provides a valuable subject for studying low-symmetry carbon materials. In this work, we employed first-principles calculations to explore the geometric structure and electronic properties of cyclo[13]carbon through various techniques such as vibrational mode analysis, bond order analysis, spin density analysis, electron localization analysis, electrostatic potential and van der Waals potential analysis, visualization of weak interactions, and energy decomposition analysis. We investigated the interaction characteristics of cyclo[13]carbon with small molecules and examined its dimer formation mechanism and dynamics features using ab initio molecular dynamics. Our study reveals the unique physicochemical properties of this novel carbon ring system. The antiaromaticity of the low-symmetry cyclo[13]carbon sets it apart from previously synthesized even-numbered carbon rings, with van der Waals interactions playing a crucial role in its binding with small molecules and in the formation of C13 dimers. This research provides theoretical insights that complement experimental observations and theoretical studies, aiding further investigation into the diverse properties of fresh carbon material isomers and promoting the synthesis and application of novel molecular materials in molecular electronics and nanotechnology.

Theoretical Insight into the Multiple Roles of the Silyl-Phenanthroline Ligand in Ir-Catalyzed C(sp3)-H Borylation

Silyl-phenanthroline (NN'Si) ligand ancillary iridium-catalyzed C(sp3)-H borylation is investigated theoretically. Density functional theory calculations clearly disclose that the (NN'Si)IrV(H)(Bpin)3 (NN'Si = 6-[(di-tert-butylsilyl)methyl]-1,10-phenanthroline) complex is a resting state, and the (NN'Si)IrIII(Bpin)2 complex serves as an active species in the catalytic cycle. The remarkably high activity of this type of a catalyst arises from the rapid reductive elimination of HBpin from (NN'Si)IrV(H)(Bpin)3 to generate the active species (NN'Si)IrIII(Bpin)2. The silyl group plays a crucial role in accelerating the crucial hydride-migration elementary step, which allows the isomerization of the (NN'Si)IrV(R)(H)(Bpin)2 intermediate to achieve the C(sp3)-B reductive elimination and afford the borylated product. Although C(sp3)-H borylation with HBpin is thermodynamically unfavorable, the Ir-dihydride intermediate (NN'Si)IrV(H)2(Bpin)2 generated after product formation is slightly more stable than resting-state (NN'Si)IrV(H)(Bpin)3 in this catalytic cycle, which is an important driving force for the HBpin reaction. Such success was not attained by many other traditional bidentate ligands. The unique regioselectivity of n-butyl ethyl ether and 2-methylheptane, induced by the NN'Si-pincer ligand, is well reproduced and the underlying reason for the selectivity is clearly elucidated.

High-performance cellulose/thermoplastic polyurethane composites enabled by interaction-modulated cellulose regeneration

Strong interfacial adhesion between cellulose and other polymers is critical to achieve the properties required for specific applications in composite materials. Here, we developed a method for the simultaneous homogeneous dissolution of cellulose and thermoplastic polyurethane (TPU) in 1,8-diazabicyclo (5.4.0) undec-7-ene levulinate/dimethyl sulfoxide ([DBUH]Lev/DMSO) solvent. This process is essential for preparing cellulose/TPU composite films and fibers through interaction-modulated cellulose regeneration. Both cellulose and TPU can be easily dissolved together in [DBUH]Lev/DMSO solvent under mild conditions. The resulting cellulose/TPU solutions exhibited strong temperature sensitivity, shear-thinning behavior and viscoelasticity, making them suitable for cast films and continuous spinning. More importantly, research findings, including density functional theory calculations and experimental characterization, confirmed the high compatibility and interaction modulability of cellulose and TPU in the composite films. The representative C90T10 sample (cellulose/TPU, 90/10) showed high transparency (90 % at 800 nm) and excellent mechanical properties (tensile strength: 176 MPa; elongation at break: 8.1 %). Additionally, the maximum tensile strength and elongation at the break of the composite fiber from C90T10 were 214 MPa and 48.1 %, respectively. This method may provide a feasible approach to design and produce homogeneous environmentally friendly composites of cellulose and other polymers at the molecular level.

Polydopamine coating for enhanced electrostatic adsorption of methylene blue by multiwalled carbon nanotubes in alkaline environments

The removal of dye molecules in alkaline environments is an issue that should receive increased attention. In this study, the interaction mechanism between polydopamine-modified multiwalled carbon nanotubes (P-MWCNTs) and multiwalled carbon nanotubes (MWCNTs) with the cationic dye methylene blue (MB) in alkaline environments was explained in depth by adsorption, spectroscopy, and density functional theory (DFT). The mechanism of action and dominant forces between the adsorbent and adsorbate were analyzed graphically by introducing energy decomposition analysis (EDA) and an independent gradient model (IGM) into the DFT calculations. In addition, the force distribution was investigated through an isosurface. Moreover, batch adsorption studies were conducted to evaluate the performance of MWCNTs and P-MWCNTs for MB removal in alkaline environments. The maximum MB adsorption capacities of the MWCNTs and P-MWCNTs in solution were 113.3 mg‧g-1 and 230.4 mg‧g-1, respectively, at pH 9. The IGM and EDA showed that the better adsorption capacity of the P-MWCNTs originated from the enhancement of the electrostatic effect by the proton dissociation of polydopamine. Moreover, the adsorption of MB by MWCNTs and P-MWCNTs in alkaline environments was governed by dispersion and electrostatic effects, respectively. Through this study, it is hoped that progress will be made in the use of DFT to explore the mechanism of adsorbent-adsorbate interactions.

Unveiling electron transfer and radical transformation pathways in coupled electrocatalysis and persulfate oxidation reactions for complex pollutant removal

The degradation of multiple organic pollutants in wastewater via advanced oxidation processes might involve different radicals, of which the types and concentrations vary upon interacting with different pollutants. In this study, electrochemical activation of peroxymonosulfate (E/PMS) using advanced activated carbon cloth (ACC) as electrode was applied for simultaneous degradation of mixed pollutants, e.g., metronidazole (MNZ) and p-chloroaniline (PCA). 92.5 % of MNZ and 91.4 % of PCA can be degraded at the cathode and anode at a low current density and PMS concentration, respectively. The rate constants for the simultaneous removal of MNZ and PCA in the E/PMS/MNZ(PCA) system were 118 times and 6 times higher than those in the sole PMS system, and 2.5 times and 1.6 times higher than those in the E/Na2SO4/MNZ(PCA) system, respectively. Different electrochemical characteristics, EPR spectra and radical quenching tests verified that the degradation of MNZ and PCA in the optimal system proceeded primarily through non-radical-dominated oxidation, involving electron transfer and 1O2 effect. The system also exhibited low energy consumption (0.215 kWh/m-3·order-1), broad operational pH range, excellent removal efficiency for water matrix, and low by-products toxicity, indicating its strong potential for practical applications. The ACC, with its super stable, low cost, and electrochemical activity, make it as a promising materials applicable in the E/PMS system for degradation of multiple pollutants. The study further elucidated the mechanism of pollutant interaction with electrode materials in terms of radical and non-radical transformation, providing fundamental insight into the application of this system for treatment of complex wastewater.

Green preparation of polydopamine-modified multiwalled carbon nanotube/calcium alginate composite aerogels for effective adsorption of methylene blue

Polydopamine-modified multiwalled carbon nanotube/calcium alginate (P-CNTs/CA) aerogel was greenly prepared. The synthesis method of the P-CNTs/CA aerogel was evaluated for its environmental friendliness. SEM, FT-IR, Raman, TGA, BET, XPS, and Zeta potential characterized the P-CNTs/CA aerogel. Batch adsorption experiments were conducted to assess the adsorption efficacy of the P-CNTs/CA aerogel on methylene blue (MB). The results demonstrated that the maximum theoretical adsorption capacity of the P-CNTs/CA aerogel for MB was 506.12 mg‧g-1. The adsorption kinetics analysis indicated that the adsorption of MB by the P-CNTs/CA aerogel was more consistent with the pseudo-second-order model. The adsorption isotherm analysis demonstrated that the Sips model exhibited the most accurate fit to the experimental data. The adsorption thermodynamics showed that the adsorption process was spontaneous and heat-absorbing. The adsorption mechanism of MB adsorption by P-CNTs/CA aerogel was analyzed graphically by the density functional theory (DFT) and independent gradient model (IGM), which revealed the involvement of hydrogen bonding, electrostatic, and dispersive interactions. In parallel, the distribution of adsorption forces was analyzed using isosurfaces. Adsorption desorption experiment showed that the P-CNTs/CA aerogel maintained 79 % removal capacity after six adsorption cycles.

Influence of side-methyl substitution position on the phase state and microwave dielectric properties of triphenylacetylene-based liquid crystals

Liquid crystal materials are well known in display applications, and their unique birefringence and electrical tunability can be utilised in microwave devices. This innovative technology modulates and filters microwave signals, replacing conventional semiconductors for a broad operational frequency band and tunable phase shift. Although isothiocyanatobiphenylacetylene-based liquid crystals exhibit low viscosity and large dielectric anisotropy, their applications in microwave communication are hampered by their broad near-crystalline phase temperature ranges. To address this limitation, this study designed and synthesized six fluorinated biphenylacetylene liquid crystal compounds with various benzene ring side-methyl substitutions (n = 3-5). The molecular structures, liquid crystal phases, and microwave dielectric properties were evaluated. Our findings indicate that compounds with methyl substitution at the Y2 position exhibited reduced melting points, an expanded nematic phase temperature range (ΔT n ≈ 92.3 °C), and an absence of near-crystalline phases. These compounds still maintain high microwave dielectric constants within the 9-30 GHz frequency band (Δε r = 0.9-1.3) and reduced maximum permittivity losses compared to their non-methyl-substituted counterparts, thereby improving the efficiency in the microwave frequency band. In contrast, the Y1 position substitution results in a significantly narrower nematic phase temperature range (approximately 2.6 °C on average) and a substantial decrease in the dielectric constant, with a Δε r reduction of about 0.3 compared to the Y2 substitution. This work shows that the side-methyl substitution can improve the performance of triphenylacetylene-based liquid crystals in microwave communication, providing valuable insight to aid the discovery of novel microwave liquid crystals.

Adsorption mechanism of cefradine on three microplastics: A combined molecular dynamics simulation and density functional theory calculation study

Microplastics and antibiotics are receiving increasing attention as two emerging pollutants in the aquatic ecosystem. The absorption of antibiotics by microplastics can potentially intensify their impact on marine organisms and human health. However, the detailed mechanisms underlying this interaction remain to be elucidated. Through molecular dynamics (MD) simulations and density functional theory (DFT) calculations, this study investigated the adsorption of cefradine (CED) onto three typical microplastics (MPs)-polyethylene (PE), polypropylene (PP), and polyamide (PA). The results of the molecular dynamics simulations showed that the interaction energy between CED and microplastics followed the order of PA-CED > PP-CED > PE-CED, indicating that PA microplastics had the highest adsorption capacity for CED antibiotics. The total energy contribution of the microplastics-cefradine (MPs-CED) systems suggested that the van der Waals and electrostatic interactions were the two primary mechanisms for the adsorption of CED by these three microplastics. In DFT calculations, the adsorption of CED on PA was found to be significantly influenced by both electrostatic and van der Waals effects, while the main driving force in the adsorption of PE and PP is van der Waals effect. In addition, IGMH analysis and AIM topological analysis confirmed that the adsorption of CED on PA relied heavily on the synergistic effect of hydrogen bonding and the van der Waals effect. The findings of this study validate the results obtained from molecular dynamics simulations, laying a foundation for a comprehensive exploration of the interaction mechanisms between microplastics and organic pollutants by integrating MD simulations and DFT calculations.

The surface functional groups-driven fast and catalytic degradation of naproxen on sludge biochar enhanced by citric acid

In this work, a sludge biochar (CA-SBC-300) with efficient activation of peroxymonosulfate (PMS) was prepared by citric acid modification. CA-SBC-300 achieved efficient degradation of naproxen (NPX) (95.5%) within 10 min by activating PMS. This system was highly resilient to common disruptive factors such as inorganic anions, humic acid (HA) and solution pH. The results of XPS and Raman showed that the content of oxygenated functional groups (OFGs) and the degree of defects on the sludge biochar increased after citric acid modification, which may be an important reason for the enhanced catalytic performance of SBC. In the CA-SBC-300/PMS system, 1O2 and O2•- made the main contributions to the degradation of NPX. XPS analysis and DFT calculations demonstrated that C=O/C-O and pyridine N on CA-SBC-300 were the crucial active sites for PMS activation. According to the results of UPLC-MS analysis, three possible pathways for NPX degradation were inferred. This study provided a feasible strategy for sludge resource utilization combined with efficient catalytic degradation of toxic organic contaminants in wastewater.

The Inhibition of Interfacial Ice Formation and Stress Accumulation with Zwitterionic Betaine and Trehalose for High-Efficiency Skin Cryopreservation

Cryopreservation is a promising technique for the long-term storage of skin. However, the formation of ice crystals during cryopreservation unavoidably damages skin structure and functionality. Currently, the lack of thorough and systematic investigation into the internal mechanisms of skin cryoinjury obstructs the advancement of cryopreservation technology. In this study, we identified 3 primary contributors to skin cryoinjury: interfacial ice nucleation, stress accumulation, and thermal stress escalation. We emphasized the paramount role of interfacial ice nucleation in provoking ice growth within the skin during the cooling process. This progress subsequently leads to stress accumulation within the skin. During the rewarming process, the brittleness of skin, previously subjected to freezing, experienced a marked increase in thermal stress due to ice recrystallization. Based on these insights, we developed a novel zwitterionic betaine-based solution formulation designed for cryopreservation skin. This cryoprotective agent formulation exhibited superior capability in lowering ice nucleation temperatures and inhibiting ice formation at interfaces, while also facilitating the growth of smooth and rounded ice crystals compared to sharp-edged and cornered crystals formed in aqueous solutions. As a result, we successfully achieved prolonged cryopreservation of the skin for at least 6 months, while preserving 98.7% of structural integrity and 94.7% of Young's modulus. This work provides valuable insights into the mechanisms of ice crystal damage during organ cryopreservation and profoundly impacts the field of organ transplantation and regenerative medicine.

Sustainable protein/polysaccharide aerogel for the simultaneous and efficient removal of multiple organic contaminants: Insights from DFT calculations and phenomenological mass-transfer modeling

Wastewater contains various organic contaminants that pose great hazards to human health and the environment. A protein/polysaccharide-derived aerogel, namely, ICMA, was developed as a high-performance adsorbent for the simultaneous and efficient removal of diverse contaminants from wastewater, including melanoidin (MLE), Congo red (CR), and diclofenac (DIC). Metal organic framework (UiO-66-NH2), as a regulatory factor, significantly improved the porosity and pore volume of the ICMA to enhance the capture performance of contaminants. The ICMA exhibited outstanding adsorption efficiency owing to the incorporation of ample polyamine functional groups and its well-developed pore structure, large porosity and pore volume, and remarkable heat resistance. The equilibrium capture capacities of the ICMA were 1364, 2031, and 539 mg/g for MLE, CR, and DIC, respectively, with corresponding removal efficiencies all exceeding 90%. Furthermore, the ICMA can capture cationic dyes through MLE/CR/DIC-bridging interactions. After five cycles, the used ICMA can still maintain a high contaminant removal rate/amount, demonstrating good reusability. The classic adsorption model showed that the capture of contaminants by the ICMA is a double-layered and heterogeneous adsorption orientation. A brand new LWAMTM model demonstrated that the adsorption mass-transfer process is jointly determined by the external mass conveyance, pore diffusion, and adsorption on the active site. Multiple characterizations indicated that the contaminant adsorption onto the ICMA was mainly facilitated by charge interactions, with H-bonds playing a secondary role. Quantum chemical theory simulations further provide insights into the atomic-level mechanisms involved in the capture of contaminants. Hirshfeld surface analysis revealed that the ICMA functions as both an H-bond acceptor and a donor during contaminant adsorption. Scale-up and upgrade adsorption were performed to treat actual/simulated wastewater, establishing the groundwork for the industrial implementation of the ICMA.

A highly selective and sensitive rhodamine B-based chemosensor for Sn4+ in water-bearing and biomaging and biosensing in zebrafish

A novel colorimetric-fluorescent dual-mode chemosensor (JT5) based on rhodamine B has been produced for monitoring Sn4+ in the DMSO/H2O (4:1, v/v) medium. It has high sensitivity, a low detection limit, a short response time (1 s) and high stability, and can still be maintained after two weeks with the red dual fluorescence/ colorimetric response. Enhancement of red fluorescence (591 nm) and red colorimetric (567 nm) response of JT5 by Sn4+ addition. The electrostatic potential of the sensor JT5 molecule was simulated to speculate on the sensing mechanism, and the IR, mass spectrometry and 1H NMR titration were utilized to further demonstrate that JT5 was coordinated to Sn4+ with a 1:1 type, the rhodamine spironolactam ring of JT5 opens up to form a penta-membered ring with Sn4+, meanwhile, its system may have chelation enhanced fluorescence (CHEF) effect. In addition, theoretical calculations were carried out to give the energy gaps of JT5 and [JT5 + Sn4+] as well as to simulate the electronic properties of the maximal absorption peaks. Notably, the sensor JT5 was successfully applied to monitoring Sn4+ in zebrafish, and the JT5-loaded filter paper provided a solid-state platform for detecting Sn4+ by both naked eye and fluorescent methods. In summary, this work contributes to monitoring Sn4+ in organisms and solid-state materials and promotes understanding of Sn4+ functions in biological systems, environments, and solid-state materials.

Rational Design of Fluorinated 2D Polymer Film Based on Donor-Accepter Architecture toward Multilevel Memory Device for Neuromorphic Computing

Fluorine-containing 2D polymer (F-2DP) film is a desired system to regulate the charge transport in organic electronics but rather rarely reports due to the limited fluorine-containing building blocks and difficulties in synthesis. Herein, a novel polar molecule with antiparallel columnar stacking is synthesized and further embedded into an F-2DP system to control over the crystallinity of F-2DP film through self-complementary π-electronic forces. The donor-accepter-accepter'-donor' (D-A-A'-D') structure regulates the charge transportation efficiently, inducing multilevel memory behavior through stepwise charge capture and transfer processes. Thus, the device exhibits ternary memory behavior with low threshold voltage (Vth1 of 1.1 V, Vth2 of 2.0 V), clearly distinguishable resistance states (1:102:104) and ternary yield (83%). Furthermore, the stepwise formation of the charge complex endows the device with a wider range to regulate the conductive state, which allows its application in brain-inspired neuromorphic computing. Modified National Institute of Standards and Technology recognition can reach an accuracy of 86%, showing great potential in neuromorphic computing applications in the post-Moore era.

A 3,5-dinitropyridin-2yl Substituted Flavonol-based Fluorescent Probe for Rapid Detection of H2S in Water, Foodstuff Samples and Living Cells

A novel flavonol-based fluorescent probe, Fla-DNT, has been synthesized for the rapid and specific detection of H2S. Fla-DNT exhibits excellent selectivity and anti-interference properties, a short response time (4 min), large Stokes shift (138 nm), and low detection limit (1.357 µM). Upon exposure to H2S, Fla-DNT displays a remarkable increase in fluorescence intensity at 542 nm. Meanwhile, the recognizing site of H2S was predicted through Electrostatic potential and ADCH charges calculations, while the sensing mechanism of H2S was determined via HRMS analysis and DFT calculation. More importantly, the probe owes multiple applications, such as a recovery rate ranging from 92.00 to 102.10% for detecting H2S in water samples, and it can be fabricated into fluorescent strips to track H2S production during food spoilage by tracking color changes, thereby enabling real-time monitoring of food freshness. The bioimaging experiments demonstrate the capability of Fla-DNT to detect both endogenous and exogenous H2S in living cells. These results provide a reliable method and idea for H2S detection in complex environments.

Molecular-docking electrolytes enable high-voltage lithium battery chemistries

Ideal rechargeable lithium battery electrolytes should promote the Faradaic reaction near the electrode surface while mitigating undesired side reactions. Yet, conventional electrolytes usually show sluggish kinetics and severe degradation due to their high desolvation energy and poor compatibility. Here we propose an electrolyte design strategy that overcomes the limitations associated with Li salt dissociation in non-coordinating solvents to enable fast, stable Li chemistries. The non-coordinating solvents are activated through favourable hydrogen bond interactions, specifically Fδ--Hδ+ or Hδ+-Oδ-, when blended with fluorinated benzenes or halide alkane compounds. These intermolecular interactions enable a dynamic Li+-solvent coordination process, thereby promoting the fast Li+ reaction kinetics and suppressing electrode side reactions. Utilizing this molecular-docking electrolyte design strategy, we have developed 25 electrolytes that demonstrate high Li plating/stripping Coulombic efficiencies and promising capacity retentions in both full cells and pouch cells. This work supports the use of the molecular-docking solvation mechanism for designing electrolytes with fast Li+ kinetics for high-voltage Li batteries.

Rhamnolipids-based bio-supramolecular solvents as green and sustainable media for extraction of pyrethroid insecticides in water and food matrices

A novel bio-supramolecular solvent (bio-SUPRAS) based on rhamnolipids (RLs) was designed for efficient extraction of pyrethroid insecticides in water and food matrices. Benefiting from RLs as amphiphiles equipped with the attractive properties of bio-degradable, low toxicity and high stability, bio-SUPRAS was spontaneously generated through salt induced coagulation. The bio-SUPRAS was characterized by cryo-scanning electron microscope and main factors influencing the extraction performance were investigated in detail. Under the optimized conditions, the method was found to have desirable limits of detection (5∼10 μg l-1), good precision (RSDs<16.9 %) and satisfactory recovery (75.2 %∼94.3 %). More importantly, the extraction mechanism was studied by density functional theory systematically. Following greenness assessment, the technique was successfully used for enrichment of pyrethroid pesticides in real samples before HPLC-UV analysis. Thus, the method showed the outstanding merits of eco-efficient, green, time-saving, and had favorable application prospect to remove trace analytes from intricate sample matrices.

Theoretical Prediction and Comprehensive Characterization of an All-Nitrogenatomic Ring, Cyclo[18]Nitrogen (N18)

The cyclic molecule cyclo[18]carbon composed of 18 carbon atoms has been observed in condensed phase experiment in recent years and has attracted great attention. Through state-of-art quantum chemistry calculation, this study found that 18 nitrogen atoms can also form a macrocyclic system, cyclo[18]nitrogen (N18), though its lifetime is very short at room temperature and can only exist for a relatively long time at very low temperatures. We comprehensively theoretically studied properties of N18, including geometric configurations, thermal decomposition mechanism and rate, molecular dynamics behavior, energetic properties, vibrational and electronic spectra. We also discussed in depth the electronic structure of N18, including nature of the N-N bonds, lone-pairs, charge distribution characteristics, electronic delocalization, and aromaticity. This work is not only the first exploration of the macrocyclic N18 molecule, but also the first time to systematically examine a very long-chain substance fully composed of nitrogen atoms in isolated state.

Enhancing the supercapacitive performance of a carbon-based electrode through a balanced strategy for porous structure, graphitization degree and N,B co-doping

Regarding carbon-based electrodes, simultaneously establishing a well-defined meso-porous architecture, introducing abundant hetero-atoms and improving the graphitization degree can effectively enhance their capacitive performance. However, it remains a significant challenge to achieve a good balance between defects and graphitization degree. In this study, the porous structure and composition of carbon materials are co-optimised through a 'dual-function' strategy. Briefly, K3Fe(C2O4)3 and H3BO3 were hybridised with a gelatin aqueous solution to form a homogeneous composite hydrogel, followed by lyophilisation and carbonisation. Owing to the dual functionality of raw materials, the graphitization, activation and hetero-atom doping processes can occur simultaneously during a one-step high-temperature treatment. The resultant carbon material exhibits a high graphitization degree (ID/IG = 0.9 ± 0.1), high hetero-atom content (N: 9.0 ± 0.3 at.%, B: 6.9 ± 0.5 at.%) and a large specific area (1754 ± 58 m2/g). The as-prepared electrode demonstrates a superior capacitance of 383 ± 1F g-1 at 1 A/g. Interestingly, the cyclic voltammetry (CV) curves exhibit a distinctive pair of broad redox peaks, which is uncommon in KOH electrolyte. Experiment data and density functional theory (DFT) simulation verify that N-5, B co-doping enhances the activity of the faradic reaction of carbon electrodes in KOH electrolyte. Furthermore, the fabricated Zn-ion hybrid supercapacitor (ZHSC) based on this carbon electrode delivers a high-energy density of 140.7 W h kg-1 at a power density of 840 W kg-1.

Molecular Interactions of Perfluorinated and Branched Fluorine-Free Surfactants at Interfaces: Insights from a New Reliable Force Field

Per- and polyfluoroalkyl substances (PFAS) constitute a class of synthetic compounds with exceptional interfacial properties. Their widespread use in many industrial applications and consumer products, combined with their remarkable chemical and thermal stability, has led to their ubiquitous presence in environmental matrices, including surface water and groundwater. To replace PFAS with fluorine-free surfactants, it is necessary first to develop a deep molecular-level understanding of the mechanisms responsible for the exceptional properties of PFAS. For instance, it has been shown that fluorine-free surfactants with highly branched or methylated chains can achieve low surface tensions at air-water interfaces and can provide highly hydrophobic surface coatings. Although molecular simulations combined with experiments are promising for uncovering these mechanisms, the reliability of simulation results depends strongly on the accuracy of the force fields implemented. At the moment, atomistic force fields are not available to describe PFAS in a variety of environments. Ab initio methods could help fill this knowledge gap, but they are computationally demanding. As an alternative, ab initio calculations could be used to develop accurate force fields for atomistic simulations. In this work, a new algorithm is proposed, which, built from accurate ab initio calculations, yields force fields for perfluorinated sulfonic and perfluoroalkyl acids. The accuracy of the new force field was benchmarked against solvation free energy and interfacial tension data. The new force fields were then used to probe the interfacial behavior of the PFAS surfactants. The interfacial properties observed in our simulations were compared with those manifested by two branched fluorine-free surfactants. The good agreement achieved with experiments and ab initio calculations suggests that the proposed protocol could be implemented to study other perfluorinated substances and help in the design of fluorine-free surfactants for targeted applications.

Optimization Strategy for Formaldehyde Removal by Carbon Cathode Electro-Fenton: Enhancement of Formaldehyde and Oxygen Co-adsorption by Rational Nitrogen Doping Types

This study investigates the effect of N-doped coal-based activated carbon cathode on formaldehyde-oxygen coadsorption. Further investigation investigates the effect of formaldehyde-oxygen coadsorption on H2O2 generation and formaldehyde removal in an electro-Fenton system. Nitrogen doping enhances formaldehyde and oxygen coadsorption by modulating competitive adsorption. Density Functional Theory (DFT) calculations confirm pyrrole nitrogen favors formaldehyde, and graphite nitrogen favors oxygen adsorption. N-doped activated carbon adsorbs 0.36 mg of formaldehyde and 0.1 mg of oxygen in 120 min and removes 82.43% of formaldehyde after electro-Fenton treatment. N-doped activated carbon enhances the synergistic adsorption of formaldehyde and oxygen. In the synergistic adsorption process, the amount of formaldehyde adsorbed is greater than the amount of oxygen adsorbed. This improves the removal efficiency of formaldehyde by electro-Fenton technology. It provides a new method for electro-Fenton removal of organic pollutants.

High energy barrier hydroxyl radical dissociation mechanism of a low shock sensitivity dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate (TKX-50) explosive

As a representative of the new generation of high-energy explosives, TKX-50 has attracted widespread attention due to its remarkably low sensitivity toward shock. However, the reported decomposition barriers of TKX-50 (∼37 kcal mol-1) are comparable to those of commonly used explosives. The mechanism of its low shock sensitivity remains unclear. In this study, using an ab initio molecular dynamics method combined with a multiscale shock simulation technique and transition state calculations (at the B2PLYP-D3/Def2TZVP level), we discovered an unconventional reaction pathway of TKX-50 under shock, and its rate-controlling step is the dissociation of the hydroxyl radical (OH) from the anion ring after proton transfer, followed by ring rupture and the production of H2O and N2. The barrier for this OH dissociation reaction is as high as 51.9 kcal mol-1. In contrast, under thermal stimuli, TKX-50 prefers to open rings directly after proton transfer without losing the OH. The corresponding barrier is 35.4 kcal mol-1, which is in good agreement with previous studies. The reason for the unconventional reaction pathway of TKX-50 under shock may be the suppression of anion ring opening in thermal decomposition by steric hindrance upon shock compression. In addition, the dominant N2 generation pathway under shock releases less energy than pyrolysis which further explains the low shock sensitivity of TKX-50. This study comprehensively elucidates the different reaction mechanisms of TKX-50 under thermal and shock conditions and proposes a crucial reaction pathway leading to its low shock sensitivity. These findings will contribute to the understanding and application of tetrazole anionic energetic salts.

Interaction between hydroxymethanesulfonic acid and several organic compounds and its atmospheric significance

The interactions of the micro-mechanism of hydroxymethanesulfonic acid (HMSA) with the typical small organic molecule in atmospheric (X = methanol, formaldehyde, formic acid, methyl formate, dimethyl ether, acetone) has been investigated by density functional theory (DFT), quantum theory of atoms in molecules (QTAIM), Generalized Kohn-Sham Enery Decomposition Analysis (GKS-EDA) and the atmospheric clusters dynamic code (ACDC). The results of DFT show that the stable six- to eight-membered ring structures are easily formed in HMSA-X clusters. According to the topological analysis results of the AIM theory and the IRI method, a strong hydrogen bonding interaction is present in the complex. GKS-EDA results show that electrostatic energy is the main contributor to the interaction energy as it accounts for 51 %-55 % of the total attraction energy. The evaporation rates of HMSA-HMSA and HMSA-HCOOH clusters were much lower than those of the other HMSA complexes. In addition, the Gibbs energy of formation (ΔG) of HMSA-X dimers is investigated under atmosphere temperature T = 217-298 K and p = 0.19-1.0 atm, the ΔG decreased with decreasing of the atmosphere temperature and increased with the decrease of atmospheric pressure, indicating that the low temperature and high pressure may significantly facilitate to the formation of dimers.

Multiple Applications of a Novel Fluorescence Probe with Large Stokes Shift and Sensitivity for Rapid H2S Detection

Herein, a novel fluorescence probe Fla-DNP based on flavonol has been designed and synthesized for rapid, specific detection of H2S. With the addition of H2S, Fla-DNP triggered thiolysis and released Fla displaying the "turn-on" fluorescence response at 566 nm, which is consistent with the reaction site predicted by calculating Electrostatic potential and ADCH charges. As an easily available H2S probe, Fla-DNP has the advantages of high selectivity, anti-interference, low detection limit (0.834 μM), short response time (6 min), and large Stokes shift (124 nm). The sensing mechanism of H2S was determined by HRMS analysis and DFT calculation. Moreover, Fla-DNP processes a wide range of multiple applications, including the detection of H2S in environmental water samples with good recovery rates ranging from 89.6% to 102.0%, as well as tracking the production of H2S during food spoilage. Meanwhile, the probe exhibits superior biocompatibility and can not only be available used for H2S detection in living cells but be further designed as an H2S-activated CO photoreleaser, based on which it can be developed as a targeted anti-cancer drug.

Exploring the Structural Attributes of Yoda1 for the Development of New-Generation Piezo1 Agonist Yaddle1 as a Vaccine Adjuvant Targeting Optimal T Cell Activation

Piezo1, a mechano-activated ion channel, has wide-ranging physiological and therapeutic implications, with the ongoing development of specific agonists unveiling cellular responses to mechanical stimuli. In our study, we systematically analyzed the chemical subunits in Piezo1 protein agonist Yoda1 to comprehend the structure-activity relationship and push forward next-generation agonist development. Preliminary screening assays for Piezo1 agonism were performed using the Piezo1-mCherry-transfected HEK293A cell line, keeping Yoda1 as a positive control. We introduce a novel Piezo1 agonist Yaddle1 (34, 0.40 μM), featuring a trifluoromethyl group, with further exploration through in vitro studies and density functional theory calculations, emphasizing its tetrel interactions, to act as an ambidextrous wedge between the domains of Piezo1. In contrast to the poor solubility of the established agonist Yoda1, our results showed that the kinetic solubility of Yaddle1 (26.72 ± 1.8 μM at pH 7.4) is 10-fold better than that of Yoda1 (1.22 ± 0.11 μM at pH 7.4). Yaddle1 (34) induces Ca2+ influx in human CD4+ T cell, suggesting its potential as a vaccine adjuvant for enhanced T cell activation.

New insight into the role of the self-assembly of heteroatom compounds in heavy oil viscosity enhancement

Unveiling the role of heteroatom compounds in heavy oil viscosity is pivotal for finding targeted viscosity reduction methods to improve oil recovery. This research investigates the impact of heteroatoms in asphaltene molecules by utilizing quantum chemical calculations and molecular dynamics simulations to analyze their electrostatic potential characteristics, pairwise interactions, and dynamic behavior within realistic reservoirs. Heteroatom compounds can influence the molecular-level properties of asphaltenes and thus impact the macroscopic behavior of heavy oils. Research results suggest that the presence of ketone and aromatic rings in asphaltene molecules leads to the unrestricted movement of pi electrons due to their collective electronegativity. Two distinct configurations of asphaltene dimers, face-to-face, and edge-to-face, were observed. Intermolecular interactions were predominantly governed by van der Waals forces, highlighting their significant role in stabilizing asphaltene aggregates. The distribution of asphaltene molecules in the oil phase can be summarized as the "rebar-cement" theory. In the heteroatom-free system, the face-to-face peaks in the radial distribution function exhibit significantly reduced magnitudes compared to those in the heteroatom-containing system. This emphasizes the pivotal function of heteroatoms in connecting molecular components to form a more compact asphaltene structure, which may result in a higher viscosity of heavy oil. These findings give insight into the significance of heteroatoms in bridging molecular components and shaping the intricate structure of asphaltene and advance our understanding of heavy oil viscosity properties.

Experimental detection of the diamino-pentazolium cation and theoretical exploration of derived high energy materials

In this work, we realized the detection of diamino-pentazolium cation (DAPZ+) in the reaction solution experimentally and proved it to be meta-diamino-pentazole based on the transition state theory. Quantum chemical methods were used to predict its spectral properties, charge distribution, stability and aromaticity. Considering that DAPZ+ has excellent detonation properties, it was further explored by assembling it with N5-, N3- and C(NO2)3- anions, respectively. The results show a strong interaction between DAPZ+ and the three anions, which will have a positive effect on its stability. Thanks to the high enthalpy of formation and density, the calculated detonation properties of the three systems are exciting, especially [DAPZ+][N5-] (D: 10,016 m·s-1; P: 37.94 GPa), whose actual detonation velocity may very likely exceed CL-20 (D: 9773 m·s-1). There is no doubt that this work will become the precursor for the theoretical exploration of new polynitrogen ionic compounds.

Green moisture-electric generator based on supramolecular hydrogel with tens of milliamp electricity toward practical applications

Moisture-electric generators (MEGs) has emerged as promising green technology to achieve carbon neutrality in next-generation energy suppliers, especially combined with ecofriendly materials. Hitherto, challenges remain for MEGs as direct power source in practical applications due to low and intermittent electric output. Here we design a green MEG with high direct-current electricity by introducing polyvinyl alcohol-sodium alginate-based supramolecular hydrogel as active material. A single unit can generate an improved power density of ca. 0.11 mW cm-2, a milliamp-scale short-circuit current density of ca. 1.31 mA cm-2 and an open-circuit voltage of ca. 1.30 V. Such excellent electricity is mainly attributed to enhanced moisture absorption and remained water gradient to initiate ample ions transport within hydrogel by theoretical calculation and experiments. Notably, an enlarged current of ca. 65 mA is achieved by a parallel-integrated MEG bank. The scalable MEGs can directly power many commercial electronics in real-life scenarios, such as charging smart watch, illuminating a household bulb, driving a digital clock for one month. This work provides new insight into constructing green, high-performance and scalable energy source for Internet-of-Things and wearable applications.

Design, Synthesis, and Mode of Action of Thioacetamide Derivatives as the Algicide Candidate Based on Active Substructure Splicing Strategy

Lakes and reservoirs worldwide are experiencing a growing problem with harmful cyanobacterial blooms (HCBs), which have significant implications for ecosystem health and water quality. Algaecide is an effective way to control HCBs effectively. In this study, we applied an active substructure splicing strategy for rapid discovery of algicides. Through this strategy, we first optimized the structure of the lead compound S5, designed and synthesized three series of thioacetamide derivatives (series A, B, C), and then evaluated their algicidal activities. Finally, compound A3 with excellent performance was found, which accelerated the process of discovering and developing new algicides. The biological activity assay data showed that A3 had a significant inhibitory effect on M. aeruginosa. FACHB905 (EC50 = 0.46 μM) and Synechocystis sp. PCC6803 (EC50 = 0.95 μM), which was better than the commercial algicide prometryn (M. aeruginosa. FACHB905, EC50 = 6.52 μM; Synechocystis sp. PCC6803, EC50 = 4.64 μM) as well as better than lead compound S5 (M. aeruginosa. FACHB905, EC50 = 8.80 μM; Synechocystis sp. PCC6803, EC50 = 7.70 μM). The relationship between the surface electrostatic potential, chemical reactivity, and global electrophilicity of the compounds and their activities was discussed by density functional theory (DFT). Physiological and biochemical studies have shown that A3 might affect the photosynthesis pathway and antioxidant system in cyanobacteria, resulting in the morphological changes of cyanobacterial cells. Our work demonstrated that A3 might be a promising candidate for the development of novel algicides and provided a new active skeleton for the development of subsequent chemical algicides.

Spectra-Based Machine Learning for Predicting the Statistical Interaction Properties of CO Adsorbates on Surface

Theoretical analyses of small-molecule adsorption on heterogeneous catalyst surfaces often rely on simplified models of molecular adsorption with the most favorable configuration. Given that real-world experimental tests frequently entail multiple molecules interacting with the surface, there is a pressing need for a comprehensive multimolecule adsorption model to bridge the gap between theory and experiment. Using machine learning, we predict the average values of important adsorption properties from conformationally averaged, calculated infrared and Raman spectra and compare these values to those theoretically derived from the conformationally averaged ensemble. Remarkably, our approach yields excellent predictions even when faced with large and indeterminate numbers of surface molecules. These quantitative spectra-averaged property relationships provide a theoretical framework for extracting key interaction properties from the spectra of real chemical environments.

Quantum chemical study on the catalytic debromination mechanism of brominated epoxy resins

The study employed Density Functional Theory (DFT) to investigate the catalytic debromination mechanism of brominated epoxy resins (BERs) by iron (Fe) and copper (Cu) catalysts. By introducing electric field (EF), intramolecular electron transfer and polarization effects on BERs debromination were explored and experimentally validated. Results indicated that the bond dissociation energy (BDE) of the C-Br bond was 312.27 kJ/mol without catalysis, while with Fe, Cu, and EF, it was 114.47 kJ/mol, 94.85 kJ/mol, and 292.59 kJ/mol, respectively, enhancing reactivity. EF parallel to the C-Br bond and oriented toward the C atom, altered electrostatic potential and dipole moment around C-Br bond, leading to 68.60% and 50.19% increment in electronic contribution difference and molecule polarity, respectively, thereby reducing the C-Br BDE. Fe and Cu facilitated electron transfers with BERs, inducing reactions between their negative electrostatic potentials and Br's positive potential, changing electron sharing, resulting in 19.87% and 12.11% increase in polarity, respectively, and further BDE reduction. Structural modifications by the EF and catalysts also intensified van der Waals forces with bromine atoms and decreased spatial hindrance, collectively making C-Br bond breakage easier. Experiments revealed the EF enhanced BERs' debromination efficiency but hindered Fe/Cu's catalysis at lower temperatures.

A Novel Coating System Based on Layered Double Hydroxide/HQS Hierarchical Structure for Reliable Protection of Mg Alloy: Electrochemical and Computational Perspectives

Growing research activity on layered double hydroxide (LDH)-based materials for novel applications has been increasing; however, promoting LDH layer growth and examining its morphologies without resorting to extreme pressure conditions remains a challenge. In the present study, we enhance LDH growth and morphology examination without extreme pressure conditions. By synthesizing Mg-Al LDH directly on plasma electrolytic oxidation (PEO)-treated Mg alloy surfaces and pores at ambient pressure, the direct synthesis was achieved feasibly without autoclave requirements, employing a suitable chelating agent. Additionally, enhancing corrosion resistance involved incorporating electron donor-acceptor compounds into a protective layer, with 8-Hydroxyquinoline-5-sulfonic acid (HQS) that helps in augmenting Mg alloy corrosion resistance through the combination of LDH ion-exchange ability and the organic layer. DFT simulations were used to explain the mutual interactions in the LDH system and provide a theoretical knowledge of the interfacial process at the molecular level.

Highly efficient adsorption of ciprofloxacin from aqueous solutions by waste cation exchange resin-based activated carbons: Performance, mechanism, and theoretical calculation

This study focused on the preparation of a highly efficient activated carbon adsorbent from waste cation exchange resins through one-step carbonization to remove ciprofloxacin (CIP) from aqueous solutions. Scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectrometry, and X-ray photoelectron spectroscopy were used to characterize the physicochemical properties of the carbonized materials. The CIP removal efficiency, influencing factors, and adsorption mechanisms of CIP on the carbonized resins were investigated. Density functional theory (DFT) computations were performed to elucidate the adsorption mechanisms. The CIP removal reached 93 % when the adsorbent dosage was 300 mg/L at 25 °C. The adsorption capacity of the carbonized resins to CIP gradually decreased with an increasing pH from 3.0 to 7.0 and sharply declined with a pH from 7.0 to 11.0. The adsorption process better fitted by the pseudo second-order kinetic and Langmuir models, indicating that the interaction between CIP and the carbonized resins was monolayer adsorption. The maximum adsorption capacity fitted by the Langmuir model was 384.4 mg/g at 25 °C. Microstructural analysis showed that the adsorption of CIP on the carbonized resins was a joint effect of H-bonding, ion exchange, and graphite-N adsorption. Computational results signified the strong H-bonding and ion exchange interactions existed between CIP and carbonized resins. The high adsorption and reusability suggest that waste cation exchange resin-based activated carbons can be used as an effective and reusable adsorbent for removing CIP from aqueous solutions.

Observation of a super-tetrahedral cluster of acetonitrile-solvated dodecaborate dianion via dihydrogen bonding

We launched a combined negative ion photoelectron spectroscopy and multiscale theoretical investigation on the geometric and electronic structures of a series of acetonitrile-solvated dodecaborate clusters, i.e., B12H122-·nCH3CN (n = 1-4). The electron binding energies of B12H122-·nCH3CN are observed to increase with cluster size, suggesting their enhanced electronic stability. B3LYP-D3(BJ)/ma-def2-TZVP geometry optimizations indicate each acetonitrile molecule binds to B12H122- via a threefold dihydrogen bond (DHB) B3-H3 ⁝⁝⁝ H3C-CN unit, in which three adjacent nucleophilic H atoms in B12H122- interact with the three methyl hydrogens of acetonitrile. The structural evolution from n = 1 to 4 can be rationalized by the surface charge redistributions through the restrained electrostatic potential analysis. Notably, a super-tetrahedral cluster of B12H122- solvated by four acetonitrile molecules with 12 DHBs is observed. The post-Hartree-Fock domain-based local pair natural orbital- coupled cluster singles, doubles, and perturbative triples [DLPNO-CCSD(T)] calculated vertical detachment energies agree well with the experimental measurements, confirming the identified isomers as the most stable ones. Furthermore, the nature and strength of the intermolecular interactions between B12H122- and CH3CN are revealed by the quantum theory of atoms-in-molecules and the energy decomposition analysis. Ab initio molecular dynamics simulations are conducted at various temperatures to reveal the great kinetic and thermodynamic stabilities of the selected B12H122-·CH3CN cluster. The binding motif in B12H122-·CH3CN is largely retained for the whole halogenated series B12X122-·CH3CN (X = F-I). This study provides a molecular-level understanding of structural evolution for acetonitrile-solvated dodecaborate clusters and a fresh view by examining acetonitrile as a real hydrogen bond (HB) donor to form strong HB interactions.