jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Elaine C. Reichert | Jakob C. Dahl | Klavs F. Jensen | Stephen L. Buchwald
Source: Journal of the American Chemical Society (article, 2024-11-20)
Field: Chemistry — Organic Chemistry

Kinetic Modeling Enables Understanding of Off-Cycle Processes in Pd-Catalyzed Amination of Five-Membered Heteroaryl Halides The mechanism of Pd-catalyzed amination of five-membered heteroaryl halides was investigated by integrating experimental kinetic analysis with kinetic modeling through predictive testing and likelihood ratio analysis, revealing an atypical productive coupling pathway and multiple off-cycle events. The GPhos-supported Pd catalyst, along with the moderate-strength base NaOTMS, was previously found to promote efficient coupling between five-membered heteroaryl halides and secondary amines. However, slight deviations from the optimal concentration, temperature, and/or solvent resulted in significantly lower yields, contrary to typical reaction optimization trends. We found that the coupling of 4-bromothiazole with piperidine proceeds through an uncommon mechanism in which the NaOTMS base, rather than the amine, binds first to the oxidative addition complex; the resulting OTMS-bound Pd species is the resting state. Formation of the Pd-amido complex via base/amine exchange was identified as the turnover-limiting step, unlike other reported catalyst systems for which reductive elimination is turnover-limiting. We determined that the amine-bound Pd complex, usually an on-cycle intermediate, is instead a reversibly generated off-cycle species, and that base-mediated decomposition of 4-bromothiazole is the primary irreversible catalyst deactivation pathway. Predictive testing and kinetic modeling were key to the identification of these off-cycle processes, providing insight into minor mechanistic pathways that are difficult to observe experimentally. Collectively, this report reveals the unique enabling features of the Pd-GPhos/NaOTMS system, implementing mechanistic insights to improve the yields of particularly challenging coupling reactions. Moreover, these findings highlight the utility of applying predictive tests to kinetic models for the rapid evaluation of mechanistic possibilities in small-molecule catalytic systems. Chemistry ; Catalytic cycle ; Halide ; Catalysis ; Amine gas treating ; Amination ; Piperidine ; Combinatorial chemistry ; Computational chemistry ; Photochemistry ; Stereochemistry ; Organic chemistry Catalytic Cross-Coupling Reactions ; Asymmetric Hydrogenation and Catalysis ; Catalytic C–H Functionalization Methods
Authors: Menisha S. Karunarathna | Md Anisur Rahman | Guang Yang | Catalin Gainaru | Zoriana Demchuck | Christopher C. Bowland | Harry M. Meyer | Natasha Ghezawi | Tomonori Saito
Source: Materials Horizons (article, 2024-12-11)
Field: Materials Science — Polymers and Plastics

Tough and circular glass fiber composites <i>via</i> a tailored dynamic boronic ester interface Glass fiber reinforced polymer (GFRP) composites are valued for their strength and cost-effectiveness. However, traditional GFRPs often face challenges for end-of-life recycling due to their non-depolymerizable thermoset matrices, and long-term performance due to inadequate interfacial adhesion, which can lead to fiber-matrix delamination. Here, we have designed dynamic fiber-matrix interfaces to allow tough and closed-loop recyclable GFRPs by utilizing a vitrimer, derived from upcycled polystyrene-<i>b</i>-poly(ethylene-<i>co</i>-butylene)-<i>b</i>-polystyrene (SEBS) with boronic ester (S-Bpin) and amine-based diol crosslinker. The boronic ester groups in S-Bpin form dynamic covalent bonds with the naturally present hydroxyl groups on the unsized GF surface, which eliminates the need for fiber sizing and enables facile closed-loop recyclability of both the fibers and the vitrimer matrix. The resulting strong fiber-matrix interface, depicted by the Raman mapping, leads to a 552% increase in-plane shear toughness (6.2 ± 0.3 MJ m<sup>-3</sup>) and 27% ultimate tensile strength (361 ± 89.2 MPa) compared to those of the conventional epoxy-based matrix (0.95 ± 0.05 MJ m<sup>-3</sup> and 264 ± 59.7 MPa, respectively). The network rearrangement through dynamic boronic ester exchange enables fast thermoformability and repairability of micro-cracks at elevated temperatures. Additionally, both the matrix and composite demonstrate strong adhesion to various surfaces including steel and glasses exhibiting ≥6 MPa lap shear strength, which expands their suitability for diverse industrial applications. The readily created dynamic interface between boronic ester functionalized vitrimer and neat GFs presents a promising strategy for developing closed-loop recyclable, multifunctional structural materials, offering a sustainable alternative to non-recyclable thermoset GFRPs and contributes to a circular economy in composite materials. Materials science ; Composite material ; Glass fiber ; Interface (matter) ; Fiber Polymer composites and self-healing ; Silicone and Siloxane Chemistry ; Polymer Nanocomposites and Properties
Authors: S. Kaiser | Zhi Yue | Yuxing Peng | Trung Dac Nguyen | Sijia Chen | Da Teng | Gregory A. Voth
Source: ChemRxiv (preprint, 2024-04-02)
Field: Chemistry — Inorganic Chemistry

Molecular dynamics simulation of complex reactivity with the Rapid Approach for Proton Transport and Other Reactions (RAPTOR) soft- ware package Simulating chemically reactive phenomena such as proton transport on nanosecond to microsecond and beyond time- scales is a challenging task. Ab initio methods are unable to currently access these timescales routinely, and traditional molecular dynamics methods feature fixed bonding arrangements that cannot account for changes in the system’s bonding topology. The Mul- tiscale Reactive Molecular Dynamics (MS-RMD) method, as implemented in the Rapid Approach for Proton Transport and Other Reactions (RAPTOR) software package for the LAMMPS molecular dynamics code, offers a method to routinely sample longer timescale reactive simulation data with statistical precision. RAPTOR may also be interfaced with enhanced sampling methods to drive simulations towards the analysis of reactive rare events, and a number of collective variables (CVs) have been developed to facilitate this. Key advances to this methodology, including GPU acceleration efforts and novel CVs to model water wire formation are reviewed, along with recent applications of the method which demonstrate its versatility and robustness. Reactivity (psychology) ; Proton ; Molecular dynamics ; Computer science ; Physics ; Chemistry ; Computational chemistry ; Nuclear physics Radioactive element chemistry and processing
Authors: Guijun Wang | Anji Chen | Pramod Aryal | Jonathan Bietsch
Source: Organic & Biomolecular Chemistry (article, 2024-01-01)
Field: Materials Science — Biomaterials

Synthetic approaches of carbohydrate based self-assembling systems Carbohydrate-based self-assembling systems are essential for the formation of advanced biocompatible materials <i>via</i> a bottom-up approach. The self-assembling of sugar-based small molecules has applications encompassing many research fields and has been studied extensively. In this focused review, we will discuss the synthetic approaches for carbohydrate-based self-assembling (SA) systems, the mechanisms of the assembly, as well as the main properties and applications. This review will mainly cover recent publications in the last four years from January 2020 to December 2023. We will essentially focus on small molecule self-assembly, excluding polymer-based systems, which include various derivatives of monosaccharides, disaccharides, and oligosaccharides. Glycolipids, glycopeptides, and some glycoconjugate-based systems are discussed. Typically, in each category of systems, the system that can function as low molecular weight gelators (LMWGs) will be discussed first, followed by self-assembling systems that produce micelles and aggregates. The last section of the review discusses stimulus-responsive self-assembling systems, especially those forming gels, including dynamic covalent assemblies, chemical-triggered systems, and photoresponsive systems. The review will be organized based on the sugar structures, and in each category, the synthesis of representative molecular systems will be discussed next, followed by the properties of the resulting molecular assemblies. Biocompatible material ; Nanotechnology ; Carbohydrate ; Sugar ; Chemistry ; Materials science ; Computer science ; Biochemical engineering ; Engineering ; Biochemistry ; Biomedical engineering Supramolecular Self-Assembly in Materials ; Glycosylation and Glycoproteins Research ; Carbohydrate Chemistry and Synthesis
Authors: Frédéric Meunier | A. Kaddouri
Source: Catalysts (article, 2024-09-19)
Field: Materials Science — Materials Chemistry

Microwave-Assisted Oxidation of N2 into NOx over a La-Ce-Mn-O Perovskite Yielding Plasmas in a Quartz Flow Reactor at Atmospheric Pressure N2 oxidation to NOx is a challenging reaction, and alternative routes to the industrial Ostwald process are of interest. A perovskite under flowing O2-N2 mixtures at atmospheric pressure in a quartz tube reactor was irradiated by microwaves (MW), leading to the formation of hot spots and plasmas within the catalyst bed. NOx concentrations up to 2.5 vol.% in one pass were obtained at 600 W. Using a lower MW power of 100 W led to a pulsed mode yielding lower NOx concentrations and no noticeable damage to the quartz reactor. The formation of plasma was strongly dependent on the perovskite bed packing. The perovskite acted primarily as a susceptor and likely also as a catalyst, although the proportion of heterogeneous and homogenous reactions could not be determined in the present study. The simple reactor layout allowing operation at atmospheric pressure is promising for the development of practical MW-assisted N2 fixation technologies. NOx ; Atmospheric pressure ; Quartz ; Perovskite (structure) ; Chemical engineering ; Catalysis ; Materials science ; Microwave ; Analytical Chemistry (journal) ; Chemistry ; Metallurgy ; Environmental chemistry ; Physical chemistry ; Meteorology ; Organic chemistry Catalytic Processes in Materials Science ; Ammonia Synthesis and Nitrogen Reduction ; Industrial Gas Emission Control
Authors: Quyen Vu Thi | Quynh H. Nguyen | Yong‐Seok Choi | Seung‐Yeol Jeon | Bryan W. Boudouris | Yongho Joo
Source: JACS Au (article, 2024-02-05)
Field: Materials Science — Polymers and Plastics

Conductive Glassy Nonconjugated Open-Shell Radical Polymer with Organosulfur Backbone for Macroscopic Conductivity Nonconjugated organic radicals with an open-shell radical active group exhibit unique functionality due to their radical pendant site. Compared with the previously studied doped conjugated polymers, radical polymers reveal superior processability, stability, and optical properties. Despite the success of organic radical polymer conductors based on the TEMPO radicals, it still requires potential design substitutions to meet the fundamental limits of charge transport in the radical polymer. To do so, we demonstrate that the amorphous, nonconjugated radical polymer with backbone-pendant group interaction and low glass transition temperature enables the macromolecules to have rapid charge transport in the solid state, resulting in conductivity higher than 32 S m<sup>-1</sup>. This charge transport is due to the formation of the local ordered regime with an energetically favored orientation caused by the strong coupling between the backbone and pendant group, which can significantly modulate the polymer packing with active electronic communications. The nonconjugate nature of the radical polymer maintains an optical transparency up to 98% at a 1.5 μm thick film. Thus, this effort will be a dramatically advanced model in the organic radical community for the creation of next-generation polymer conductors. Organosulfur compounds ; Conductivity ; Conductive polymer ; Materials science ; Electrical conductor ; Polymer ; Shell (structure) ; Open shell ; Polymer chemistry ; Polymer science ; Chemical engineering ; Organic chemistry ; Chemistry ; Composite material ; Physical chemistry ; Sulfur ; Engineering Conducting polymers and applications ; Organic Electronics and Photovoltaics ; Organic Light-Emitting Diodes Research
Authors: Kehinde H. Fagbohungbe | Connor P. Callaway | Chad Risko
Source: Journal of Materials Chemistry C (article, 2024-01-01)
Field: Materials Science — Ceramics and Composites

Temperature-dependent stress–strain behavior of amorphous and crystalline P3HT Atomistic molecular dynamics (MD) simulations of ordered and disordered P3HT at varying temperatures reveal distinct thermomechanical behavior in the amorphous and crystalline material domains. Materials science ; Amorphous solid ; Composite material ; Strain (injury) ; Stress (linguistics) ; Stress–strain curve ; Crystallography ; Deformation (meteorology) Advanced ceramic materials synthesis ; Additive Manufacturing and 3D Printing Technologies ; Tribology and Wear Analysis
Authors: Tobias Keydel | Andreas Link
Source: Molecules (review, 2024-09-19)
Field: Chemistry — Organic Chemistry

Synthetic Approaches, Properties, and Applications of Acylals in Preparative and Medicinal Chemistry Diesters of geminal diols (R-CH(O-CO-R')<sub>2</sub>, RR'C(OCOR″)<sub>2</sub>, etc. with R = H, aryl or alkyl) are termed acylals according to IUPAC recommendations (Rule P-65.6.3.6 Acylals) if the acids involved are carboxylic acids. Similar condensation products can be obtained from various other acidic structures as well, but these related "non-classical acylals", as one might call them, differ in various aspects from classical acylals and will not be discussed in this article. Carboxylic acid diesters of geminal diols play a prominent role in organic chemistry, not only in their application as protective groups for aldehydes and ketones but also as precursors in the total synthesis of natural compounds and in a variety of organic reactions. What is more, acylals are useful as a key structural motif in clinically validated prodrug approaches. In this review, we summarise the syntheses and chemical properties of such classical acylals and show what potentially under-explored possibilities exist in the field of drug design, especially prodrugs, and classify this functional group in medicinal chemistry. Geminal ; Chemistry ; Organic chemistry ; Combinatorial chemistry Synthesis and Catalytic Reactions ; Chemical Reaction Mechanisms ; Click Chemistry and Applications
Authors: Lincai Peng | Shaomu Wen | Jing Yan | Huali Yu | Wen Zhan | Zhi Wang
Source: Materials (article, 2024-02-28)
Field: Materials Science — Materials Chemistry

Inhibition Effect of Triphenylmethane Dyes for the Corrosion of Carbon Steel in CO2-Saturated NaCl Corrosion Medium Carbon dioxide corrosion presents a significant challenge in the oil and gas field. This study simulates the corrosive environment characteristics of oil and gas fields to investigate the corrosion inhibition properties of three triphenylmethane dyes. The inhibitive performance and mechanisms of these dyes were analyzed through weight loss and electrochemical testing, revealing that crystal violet (CV) exhibited a superior inhibition effectiveness over malachite green (MG) and Fuchsine basic (FB). At a concentration of 150 ppm in a CO<sub>2</sub>-saturated 5% NaCl solution at 25 °C, CV achieved an impressive maximum inhibition efficiency of 94.89%. With the increase in temperature, the corrosion rate slightly decreased, and the corrosion rate was 92.94% at 60 °C. The investigated CV acted as a mixed-type corrosion inhibitor and its protection obeyed the Langmuir adsorption isotherm. The corrosion morphology was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and confocal laser scanning microscopy (CLMS). Quantum chemical calculations and molecular dynamics simulations were employed to validate the corrosion inhibition mechanisms, providing guidance for the further application of these dyes in corrosion control. Corrosion ; Triphenylmethane ; Crystal violet ; Materials science ; Scanning electron microscope ; Carbon steel ; Adsorption ; X-ray photoelectron spectroscopy ; Chemical engineering ; Corrosion inhibitor ; Nuclear chemistry ; Malachite green ; Langmuir adsorption model ; Metallurgy ; Inorganic chemistry ; Chemistry ; Composite material ; Organic chemistry Corrosion Behavior and Inhibition ; Concrete Corrosion and Durability ; Hydrogen embrittlement and corrosion behaviors in metals
Authors: Marian Arale Brännvall | Gabriel Persson | Luis Casillas‐Trujillo | Rickard Armiento | Björn Alling
Source: Physical Review Materials (article, 2024-11-19)
Field: Materials Science — Materials Chemistry

Predicting the Curie temperature of magnetic materials with automated calculations across chemistries and structures We develop a technique for predicting the Curie temperature of magnetic materials using density functional theory calculations suitable to include in high-throughput frameworks. We apply four different models, including physically relevant observables, and assess numerical constants by studying 32 ferro- and ferrimagnets. With the best-performing model, the Curie temperature can be predicted with a mean absolute error of approximately 126 K. As predictive factors, the models consider either the energy differences between the magnetic ground state and a magnetically disordered paramagnetic state, or the average constraining fields acting on magnetic moments in a disordered local moments calculation. Additionally, the energy differences are refined by incorporating the magnetic entropy of the paramagnetic state and the number of nearest magnetic neighbors of the magnetic atoms. The most advanced model is found to extend well into <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>Fe</a:mi><a:mrow><a:mn>1</a:mn><a:mtext>−</a:mtext><a:mi>x</a:mi></a:mrow></a:msub><a:msub><a:mi>Co</a:mi><a:mi>x</a:mi></a:msub></a:mrow></a:math> alloys, indicating the potential efficacy of utilizing our model in designing materials with tailored Curie temperatures by altering alloy compositions. This examination can illuminate the factors influencing magnetic transition temperatures in magnetic materials and provide insights into how they can be employed to make quantitative predictions of Curie temperatures. Our approach is not restricted to specific crystal structures or chemical compositions. It offers a more cost-effective alternative, in terms of human time and need for hands-on oversight, to other density functional theory methods for predicting the Curie temperature. As a result, it provides a practical strategy for conducting high-throughput screening for new technologically applicable magnetic materials. Alternatively, it can complement ML-based screening of magnetic materials by integrating physical principles into such approaches, thereby enhancing their prediction accuracy. Published by the American Physical Society 2024 Curie temperature ; Materials science ; Curie ; Condensed matter physics ; Nuclear magnetic resonance ; Ferromagnetism ; Physics Machine Learning in Materials Science ; X-ray Diffraction in Crystallography ; Magnetic and transport properties of perovskites and related materials
Authors: Г. Г. Гарифуллина | Alina Gizzatullina
Source: E3S Web of Conferences (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

Determination of the residual life of the pipe metal under conditions of corrosion fatigue This paper presents a method for calculating the residual metal life of pipelines with crack-like defects. The results of corrosion and fatigue tests of ordinary grade structural steel VSt3sp, widely used in the oil and gas industry, are presented. The work carried out studies on the effect of cathodic polarization on the cyclic crack resistance of VSt3sp steel under the influence of a carbonate-bicarbonate medium. Residual ; Residual stress ; Corrosion ; Materials science ; Metallurgy ; Corrosion fatigue ; Metal ; Forensic engineering ; Engineering ; Computer science Material Properties and Failure Mechanisms ; Engineering Diagnostics and Reliability ; Non-Destructive Testing Techniques
Authors: Saeed Al‐Meer | Khalid Al‐Saad | Reem Aledamat | Ahmed S. El‐Shafie | Marwa El‐Azazy
Source: Processes (article, 2024-10-14)
Field: Materials Science — Materials Chemistry

Unveiling the Power of Surfactant-Based Carbon Dots: Ultrasensitive Detection of Cadmium in Tap and Drinking Water Samples This study introduces a novel approach for transforming the cationic surfactant, cetyltrimethylammonium bromide (CTAB), into fluorescent carbon dots (CDs) capable of detecting cadmium ions at ultralow concentrations. The current approach involves preparing CDs through hydrothermal process at various pH levels. The CDs synthesized using pH 10, CTAB-CDs-10, exhibited the highest fluorescence quantum yield (QY), 14.22%. UV-Vis spectroscopy helped identify specific peaks between 210 and 300 nm, corresponding to the π–π* transitions of the aromatic C=C bonds. Transmission electron microscopic (TEM) analysis verified the uniform spherical morphology with a particle size &lt; 2.45 nm. FT-IR analysis confirmed the presence of C=C stretching vibrations. The Box–Behnken (BB) Design was used to reconnoiter the influence of three variables on the response parameter: the F0/F ratio. The best performance could be achieved at a pH of 9, after only 300 s, and a temperature of 50 °C. The developed CTAB-CDs-based nanoprobe showed an ON–OFF behavior when came in contact with cadmium (II) and demonstrated high sensitivity with a limit of detection as low as 0.06 µM (0.007 ppm) over a wide linear range of 2–103 µM. Validation tests confirmed the applicability of the CTAB-CDs-based nanoprobe for detecting cadmium (II) in tap and drinking waters with high accuracy and precision. Tap water ; Pulmonary surfactant ; Cadmium ; Carbon fibers ; Nanotechnology ; Materials science ; Environmental chemistry ; Chemistry ; Environmental science ; Environmental engineering ; Metallurgy ; Composite material Carbon and Quantum Dots Applications ; Advanced biosensing and bioanalysis techniques ; Graphene and Nanomaterials Applications
Authors: Mayara Martins Caetano | Amanda Blanque Becceneri | Marcos V. Ferreira | Rosana Maria Nascimento de Assunção | Roberto Santana da Silva | Renata Galvão de Lima
Source: ACS Omega (article, 2024-09-05)
Field: Materials Science — Materials Chemistry

Carbonized Polymer Dots: Influence of the Carbon Nanoparticle Structure on Cell Biocompatibility Carbonized polymer dots (CPDs) were obtained by using microwave irradiation under the same conditions. However, different carbogenic precursors were used, such as aromatic diamine molecules, <i>ortho</i>-phenylenediamine (<i>o</i>-OPDA), and 3,4-diaminobenzoic acid (3,4-DABA). Both carbon nanoparticles showed different structural results based on Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and atomic force microscopy analyses. However, there are similar spectroscopic (UV-visible and fluorescence emission) profiles. The photophysical results, like quantum yield (QY) and fluorescence lifetime, were not identical; CPDs-OPDA has a higher QY and fluorescence lifetime than CPDs-3,4-DABA. CPDs-3,4-DABA presents a more hydrophobic character than CPDs-OPDA and has a more negative superficial charge. Cell viability studies in both standard and tumor lines demonstrated higher cytotoxicity from CPDs-OPDA than that from CPDs-3,4-DABA. The oxidative stress identified in cells treated with CPDs-OPDA was based on reactive oxygen species and associated with nitric oxide production. CPDs-3,4-DABA showed more DPHH inhibition than CPDs-OPDA, indicating the antioxidant activity of CPDs. Carbonization ; Biocompatibility ; Materials science ; Carbon Nanoparticles ; Polymer ; Nanoparticle ; Diamine ; Molecule ; Carbon fibers ; Nanotechnology ; Chemical engineering ; Polymer chemistry ; Composite material ; Chemistry ; Organic chemistry ; Scanning electron microscope ; Composite number Carbon and Quantum Dots Applications ; Graphene and Nanomaterials Applications ; Electromagnetic wave absorption materials