Molecular Systems Design & Engineering最新文献

Cooperativity in hydrogen bonds can be crucial for the stabilization of supramolecular systems. In this contribution, we propose a simple covalent modification within a pyrazole-based trimeric rosette that significantly improves its binding strength. Using dispersion-corrected density functional theory, at the BLYP-D3(BJ)/6-311++(d,p) level, we show how an intramolecular hydrogen bond acts as a bridge between an electron-donating group and an electron-withdrawing group by moving the electron density from one group to the other one through the sigma electron system. This effect strongly enhances the inductive ability of the substituents, and further increases the synergy of the cyclic trimer.

Atmospheric corrosion, an electrochemical phenomenon, initiates the degradation of materials, primarily metals, through their interaction with environmental droplets or aerosols. This degradation extends to various aspects such as material performance, longevity, and safety, emphasizing the critical need to comprehend and inhibit corrosion, particularly in industrial and environmental settings. Structural aluminum alloys, prominently used in aerospace, automotive, and marine industries, undergo extensive scrutiny due to their susceptibility to atmospheric corrosion. Nonetheless, the absence of suitable electrochemical techniques capable of accommodating droplet volumes underscores the urgent need for advancements in corrosion research. This paper introduces an innovative and efficient multielectrode cell setup aimed at rapid screening of droplet and thin film electrolyte volumes, presenting a new high-throughput screening method. Utilizing AA6014 as a substrate, this paper demonstrates a proof of concept for this methodology. It explores the influence of a crucial parameter, pH, while considering the effects of evaporation and secondary spreading. Various organic corrosion inhibitors, including some well-known inhibitors, were examined to evaluate the impact of chemically related structures on inhibition efficiency. This investigation predominately focuses on comparing and discussing differences and similarities in inhibition performance between bulk and droplet volumes. Ultimately, this comprehensive investigation aims to enhance the understanding and management of corrosion inhibition in droplet and thin film environments.

The feasibilities of the chemical reactions of indoline were analyzed with density functional theory (DFT) simulation. A series of azo disperse dyes using indoline as a coupling component were synthesized, namely D1–D6. The synthesized dyes were investigated by UV-visible, FT-IR, ¹H-NMR and MS spectroscopies. DFT simulation was applied to analyze the spectrometric properties of designed dyes. The dyeing of polyethylene terephthalate (PET) and nylon (PA) fabrics were assessed and compared. The synthesized indoline azo disperse dyes exhibited a yellow to red hue on the PET and PA fabrics. Deep shades were achieved with increased dye concentrations for D1 and D2 for the PET and PA fabrics. Excellent rubbing fastness and good sublimation fastness were achieved. Interrelations between dye structures and dyeing performance on the PET and PA fabrics were investigated using DFT calculations.

The design of reactive biodegradable polymers and materials is an extremely important topic of research. This work presents the synthesis of a highly reactive and degradable poly(aminoamide) containing indole functional group in each repeating unit. The presence of indole functional groups allows for easy post-modification of such poly(aminoamide), enabling the synthesis of a library of functional poly(aminoamide)s via triazolinedione (TAD)–indole click reactions. Furthermore, the use of bifunctional TAD molecules facilitates the crosslinking of such poly(aminoamide), where the degree of crosslinking directly influencing the surface area of the resulting materials. The thermoreversible characteristics of such crosslinked material was also investigated. Additionally, such indole decorated poly(aminoamide) was used as an excellent platform for layer-by-layer coatings and surface functionalization. Degradation studies reveals that both the linear and crosslinked poly(aminoamide)s can be degraded in alkaline solution, where the crosslinked materials degrade faster compared to the linear analogues.

In the catalytic hydrodeoxygenation (HDO) upgrading process of biomass pyrolysis, adsorption behavior plays a crucial role in subsequent reaction processes. A comprehensive understanding of the interfacial behavior is essential for advancing novel biomaterials and commercial bio-oil. We initially establish their precise orientation on the Ni(111) surface and identify the preferential binding site by calculating the binding energy of eight model components (n-butanol, acetic acid, methyl acetate, n-hexanal, toluene, catechol, guaiacol, and 3-methyl-1,2-cyclopentanone). Differences in the electrostatic potential of functional groups and their interactions with the surface lead to surface electrostatic potential distributions, with compounds containing aldehyde functionality demonstrating increased reactivity. To account for competitive adsorption behavior among multiple molecules, ReaxFF-MD simulations were conducted to investigate the adsorption of guaiacol molecules. The inclusion of acetic acid enhances the polarization effect and non-uniformity, indicating competitive adsorption between guaiacol and acetic acid molecules. The chair conformation of acetic acid was demonstrated to be more reasonable from a kinetic perspective, leading to a stronger surface charge induction effect compared to guaiacol. Additionally, this non-uniform distribution is closely correlated with the characteristic bond activations of adsorbed active molecules, serving as a driving force to enhance further hydrogenation and deoxygenation activities of the molecules.

Owing to their excellent fluorescence properties, coumarin derivatives have diverse applications in phototherapy and optoelectronics. Coumarin derivatives with a trifluoromethyl group at the 4-position have been extensively investigated; however, studies on the photophysical properties of fluorescent 3-trifluoromethylated coumarins in solution and in the solid state are rare. Hence, in this study, the photochemical properties of a coumarin derivative incorporating a promising electron-withdrawing fluoroalkyl group at the 3-position in solution and in the crystal form were investigated in detail by absorption and fluorescence spectral measurements, density functional theory and time-dependent density functional theory calculations, and single crystal X-ray structure analysis. The aim was to verify the reasons for its excellent fluorescence emission in solution and in the crystal form. These molecular compounds are expected to have potential applications as coumarin fluorophores in fluorescent emission probes and electronic light-emitting devices.

Recent progress in bone tissue engineering (BTE) has introduced alternative treatments for sizable and non-healing bone defects. Electrical stimulation (ES) has recently been shown to influence bone cells and foster processes such as adhesion, migration, proliferation, and differentiation, which can enhance the bone regeneration process. In this study, we synthesized molybdenum disulfide (MoS₂) nanoparticles (NPs) and incorporated them into a polycaprolactone (PCL) polymeric matrix to enhance the electrical conductivity of scaffolds. The PCL/MoS₂ nanocomposites were analysed using scanning electron microscopy (SEM), water contact angle measurement, electrical conductivity, and tensile strength assessments. In vitro studies evaluated the adhesion of mesenchymal stem cells (MSCs) and the biocompatibility of the fabricated scaffolds using the MTT assay. Biomineral crystal deposition was determined via in vitro simulated body fluid (SBF) biomineralization, and alizarin red S assays demonstrated enhanced calcium phosphate deposition on the PCL/MoS₂ composite scaffold. Additionally, qPCR analysis revealed that exposing MSCs cultured on PCL/MoS₂ to ES for two weeks transcriptionally upregulated osteogenic markers (osteocalcin (OC) and alkaline phosphatase (ALP)) in cells. Using either ES or a differentiation medium alone could enhance osteogenesis. However, when both stimuli were applied concurrently, improved levels of osteogenic markers were observed. Our findings suggest that ES plays a significant role in boosting osteogenic differentiation, particularly when combined with MoS₂NPs as an osteogenic enhancer. Therefore, PCL/MoS₂ nanofibrous scaffolds can be proposed as suitable candidates for BTE, and ES holds great potential as an effective tool along with commonly used biomaterial scaffolds.

Designing donor–acceptor polymers by incorporating additional donor or acceptor units in the polymer backbone has attracted significant interest for further tuning of physical and chemical properties for organic electronic applications. In this study, we design and synthesize random donor–acceptor–donor–acceptor (D–A–D–A′, P1) and acceptor–donor–acceptor–acceptor (A–D–A′–A, P2) polymers using direct heteroarylation polymerization. Polymer P1 has alternating donor and acceptor units, whereas polymer P2 has an additional acceptor unit. For comparison purposes with parent polymers, three donor–acceptor polymers (P3–5) were synthesized. All polymers P1–5 were synthesized from three precursor units, 5-fluoro-2,1,3-benzothiadiazole, 5-diethylhexyl-3,6-bis(thiophene-2-yl)pyrrolo[3,4-c]pyrrole-1,4-dione and 3-hexylthiophene, using different compositions and sequences. Structural characterization of polymers P1–5 was carried out by ¹H NMR, GPC and FTIR spectroscopy. The electrochemical, stability and optical properties of polymers P1–5 were investigated by cyclic voltammetry and UV-vis-NIR absorption spectroscopy. All polymers exhibited narrow optical band gaps. The absorption of these polymers was red-shifted (30–100 nm) in the solid state compared to in a solution. It was observed that copolymers have different optical and electrical properties from their parent donor–acceptor polymers. Therefore, it is an effective method for the synthesis of donor–acceptor polymers with additional donor or acceptor units to tune the properties of the polymers for flexible electronic applications.

The application of single-atom catalysts offers an auspicious resolution to the obstacles introduced by the polysulfide shuttle phenomenon and the sluggish sulfur conversion kinetics in lithium–sulfur batteries (LSBs). This research presents results regarding a sulfur host that demonstrates redox activity and resistance to polymeric sulfur species (PSS). High-curvature carbon nanotubes are utilized in the construction of a single atom CoN₄ catalyst through a series of steps including pyrolysis, surface processing, electrostatic adsorption, and polymerization. Undoubtedly, the presence of cobalt (Co) atoms as discrete entities was revealed by X-ray absorption spectroscopy and transmission electron microscopy, as these atoms showed dimensions consistent with the sulfur components on the cathode side. This configuration enables catalytic activity with a remarkable 100% atomic utilization functionality. Furthermore, the DFT calculation of free energy values indicates that the reduction of LiPSs on the carbon nanotube with surface curvature is more advantageous compared to the planar carbon surface. The obtained data suggest that the sulfur cathode, which was fabricated utilizing CoSAC/CNT, demonstrates electrocatalytic capability in the transformation of soluble polysulfides to insoluble Li₂S. As a consequence, the detrimental effects of the polysulfide shuttle effect are mitigated. The recently introduced sulfur host in the LSB exhibits consistent performance over 1000 cycles. It sustains a capacity of 990 mA h g⁻¹ at a rate of 1C, with a sulfur loading of 2.0 mg cm⁻². An impressive area-specific power of 4.1 mA h cm⁻² is achieved with a considerable sulfur loading of 7 mg cm⁻². This single-atom cobalt catalyst shows significant potential as a next-generation cathode material for LSBs.

Creation of imprinted proteins (IPs) as a synthetic alternative to natural recognition systems is an important task for chemical engineering. However, the knowledge available on the theoretical study of IPs as recognition systems is limited. In this study, combined molecular docking and molecular dynamics methods were applied for the first time to study the albumin-based IPs against foodborne toxins. Changes in protein structure and intermolecular interactions between protein and foodborne toxin molecules were evaluated. Based on these theoretical computations, insights into the rational design for IPs were submitted. This approach is extremely promising for demonstrating the IP formation mechanism, identifying their properties, and introducing new concepts of IP creation based on controlling the synthesis conditions.