jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Chunyuan Kang | Songyuan Tao | Fan Yang | Chengyu Zheng | Zexing Qu | Bai Yang
Source: Angewandte Chemie (article, 2023-11-21)
Field: Materials Science — Materials Chemistry

Enabling Carbonized Polymer Dots with Color‐tunable Time‐dependent Room Temperature Phosphorescence through Confining Carboxyl Dimer Association Abstract Developing a facile strategy to realize fine‐tuning of phosphorescence color in time‐dependent room temperature phosphorescence (RTP) materials is essential but both theoretically and practically rarely exploited. Through simultaneously confining carboxyl dimer association and isolated carboxyl into the particle via a simple hydrothermal treatment of polyacrylic acid, a dual‐peak emission of red phosphorescence (645 nm) and green phosphorescence (550 nm) was observed from carbonized polymer dots (CPDs). The ratio of the two luminescent species can be well regulated by hydrochloric acid inhibiting the dissociation of carboxyl to promote hydrogen bond. Due to comparable but different lifetimes, color‐tunable time‐dependent RTP with color changing from yellow to green or orange to green were obtained. Based on the crosslinking enhanced emission effect, the phosphorescence visible time was even extended to 7 s through introducing polyethylenimide. This study not only proposes a novel and facile method for developing CPDs with color‐tunable time‐dependent RTP, but also provides a bran‐new non‐conjugated red phosphorescence unit and its definite structure. Phosphorescence ; Photochemistry ; Hydrothermal carbonization ; Materials science ; Luminescence ; Chemistry ; Carbonization ; Fluorescence ; Adsorption ; Organic chemistry ; Optoelectronics ; Optics Luminescence and Fluorescent Materials ; Carbon and Quantum Dots Applications ; Luminescence Properties of Advanced Materials
Authors: Aleksander Mroziński | Sebastian Molin | Patryk Błaszczak | Tadeusz Miruszewski | Karolina Górnicka | Jakub Karczewski | Piotr Jasiński
Source: International Journal of Hydrogen Energy (article, 2023-06-15)
Field: Materials Science — Materials Chemistry

Impact of strontium non-stoichiometry of SrxTi0.3Fe0.7O3-δ on structural, electrical, and electrochemical properties for potential oxygen electrode of intermediate temperature solid oxide cells This work presents the results of a comprehensive study on the impact of the A-site non-stoichiometry of SrxTi0.3Fe0.7O3-δ (x = 0.90, 0.95, 1.00, 1.05) ceramics on their physicochemical properties. The materials were fabricated by the conventional solid-state reaction method and their structure was determined by X-ray diffractometry, X-ray photoelectron spectroscopy and electron microscopy. Their sintering and thermal expansion properties were then evaluated. The electrical properties of the materials were determined by electrical conductivity and electrical relaxation measurements (on bulk materials) and by electrochemical impedance spectroscopy (EIS) studies of symmetrical, CGO-electrolyte based, porous electrodes. Finally, fuel cell tests with the non-stoichiometric electrodes were evaluated. To elucidate the electrochemical reaction pathways for oxygen reduction/evolution reaction, EIS measurements were carried out in different pO2 and were analysed via the distribution of relaxation times method. The results showed a dependence of materials’ properties on the A-site non-stoichiometry, which can be used to fine-tune their properties, e.g. increase the surface exchange rate or decrease the thermal expansion coefficient. Strontium ; Electrochemistry ; Stoichiometry ; Strontium oxide ; Oxide ; Oxygen ; Electrode ; Materials science ; Inorganic chemistry ; Chemistry ; Metallurgy ; Physical chemistry Advancements in Solid Oxide Fuel Cells ; Electronic and Structural Properties of Oxides ; Magnetic and transport properties of perovskites and related materials
Authors: Renata Odžak | Doris Crnčević | Antonio Sabljić | Ines Primožič | Matilda Šprung
Source: Pharmaceuticals (article, 2023-01-25)
Field: Chemistry — Organic Chemistry

Synthesis and Biological Evaluation of 3-Amidoquinuclidine Quaternary Ammonium Compounds as New Soft Antibacterial Agents Quaternary ammonium compounds (QACs) are among the most effective antimicrobial agents that have been used for more than a century. However, due to the growing trend of bacterial resistance and high toxicity of QACs, research in this field remains a pressing matter. Recent studies of the structure-activity relationship suggest that the introduction of the amide functional group into QAC structures results in soft variants that retain their antimicrobial properties while opening the possibility of fine-tuned activity regulation. Here, we report the synthesis and structure-function study of three structurally distinct series of naturally derived soft QACs. The obtained 3-amidoquinuclidine QACs showed a broad range of antibacterial activities related to the hydrophobic-hydrophilic balance of the QAC structures. All three series yielded candidates with minimal inhibitory concentrations (MIC) in the single-digit μM range. Time-resolved growth analysis revealed subtle differences in the antibacterial activity of the selected candidates. The versatile MIC values were recorded in different nutrient media, suggesting that the media composition may have a dramatic impact on the antibacterial potential. The new QACs were found to have excellent potential to suppress bacterial biofilm formation while exhibiting low ability to induce bacterial resistance. In addition, the selected candidates were found to be less toxic than commercially available QACs and proved to be potential substrates for protease degradation. These data suggest that 3-amidoquinuclidine QACs could be considered as novel antimicrobial agents that pose a low threat to ecosystems and human health. Antimicrobial ; Antibacterial activity ; Ammonium ; Biofilm ; Chemistry ; Bacterial growth ; Amide ; Bacteria ; Combinatorial chemistry ; Microbiology ; Biology ; Biochemistry ; Organic chemistry Antimicrobial agents and applications ; Synthesis and Characterization of Heterocyclic Compounds ; Phenothiazines and Benzothiazines Synthesis and Activities
Authors: Arturo E. Aguilar-Rabiela | Shahin Homaeigohar | Eduin I. González-Castillo | Mirna L. Sánchez | Aldo R. Boccaccini
Source: Polymers (article, 2023-05-24)
Field: Materials Science — Biomaterials

Comparison between the Astaxanthin Release Profile of Mesoporous Bioactive Glass Nanoparticles (MBGNs) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/MBGN Composite Microspheres In recent years, composite biomaterials have attracted attention for drug delivery applications due to the possibility of combining desired properties of their components. However, some functional characteristics, such as their drug release efficiency and likely side effects, are still unexplored. In this regard, controlled tuning of the drug release kinetic via the precise design of a composite particle system is still of high importance for many biomedical applications. This objective can be properly fulfilled through the combination of different biomaterials with unequal release rates, such as mesoporous bioactive glass nanoparticles (MBGN) and poly(3-hydroxybutyrate-<i>co</i>-3-hydroxyvalerate) (PHBV) microspheres. In this work, MBGNs and PHBV-MBGN microspheres, both loaded with Astaxanthin (ASX), were synthesised and compared in terms of ASX release kinetic, ASX entrapment efficiency, and cell viability. Moreover, the correlation of the release kinetic to phytotherapeutic efficiency and side effects was established. Interestingly, there were significant differences between the ASX release kinetic of the developed systems, and cell viability differed accordingly after 72 h. Both particle carriers effectively delivered ASX, though the composite microspheres exhibited a more prolonged release profile with sustained cytocompatibility. The release behaviour could be fine-tuned by adjusting the MBGN content in the composite particles. Comparatively, the composite particles induced a different release effect, implying their potential for sustained drug delivery applications. Composite number ; Materials science ; Mesoporous material ; Nanoparticle ; Controlled release ; Drug delivery ; Chemical engineering ; Particle size ; Astaxanthin ; Particle (ecology) ; Microsphere ; Nanotechnology ; Composite material ; Chemistry ; Organic chemistry ; Biochemistry ; Catalysis biodegradable polymer synthesis and properties ; Bone Tissue Engineering Materials ; Hydrogels: synthesis, properties, applications
Authors: Abhishek Maharana | Priyanka Sehrawat | Ashok Das | Jitendra Kumar | Debasis Sarkar
Source: Process Safety and Environmental Protection (article, 2023-10-29)
Field: Materials Science — Materials Chemistry

Multi-dimensional population balance modeling of sonocrystallization of pyrazinamide with systematic estimation of kinetic parameters based on uncertainty and sensitivity analyses Sensitivity (control systems) ; Population ; Pyrazinamide ; Nucleation ; Materials science ; Sobol sequence ; Thermodynamics ; Biological system ; Chemistry ; Physics Crystallization and Solubility Studies ; Thermal and Kinetic Analysis ; Ultrasound and Cavitation Phenomena
Authors: Dibya Jyoti Mondal | Arindam Gupta | Sanjit Konar
Source: Chemistry - A European Journal (article, 2023-04-27)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Dinuclear Iron(II) Triple Helicates Exhibiting Room Temperature Spin‐Transition Behaviour in Solid and Solution Phase Herein, three dinuclear iron(II) helicates bearing the molecular formula [Fe<sub>2</sub> (L1)<sub>3</sub> ](ClO<sub>4</sub> )<sub>4</sub> ⋅ 2CH<sub>3</sub> OH ⋅ 3H<sub>2</sub> O (complex 1), [Fe<sub>2</sub> (L2)<sub>3</sub> ](ClO<sub>4</sub> )<sub>4</sub> ⋅ 6CH<sub>3</sub> CN (complex 2), and [Fe<sub>2</sub> (L3)<sub>3</sub> ](ClO<sub>4</sub> )<sub>4</sub> ⋅ 0.5H<sub>2</sub> O (complex 3) have been synthesized using imidazole and pyridine-imine-based ligands having fluorene moiety in the backbone. A change in the ligand field strength by terminal modulation led to a change in the spin-transition behaviour from incomplete, multi-step to complete, around room temperature in the solid state. Spin transition behaviour has also been observed in the solution phase characterized using variable temperature <sup>1</sup> H nuclear magnetic resonance spectroscopy (Evans method) and correlated using UV-visible spectroscopy. Fitting the NMR data using the ideal solution model yielded the transition temperature in the order T<sub>1/2</sub> (1)<T<sub>1/2</sub> (2)<T<sub>1/2</sub> (3), which indicates an increase in the ligand field strength from complexes 1 to 3. This study accentuates the interplay between the ligand field strength, crystal packing, and supramolecular interactions in fine-tuning the spin transition behaviour effectively. Crystallography ; Moiety ; Ligand (biochemistry) ; Chemistry ; Spectrochemical series ; Phase transition ; Imine ; Ligand field theory ; Fluorene ; Spin transition ; Stereochemistry ; Condensed matter physics ; Organic chemistry ; Polymer ; Physics ; Ion Magnetism in coordination complexes ; Metal complexes synthesis and properties ; Metal-Catalyzed Oxygenation Mechanisms
Authors: М. М. Студент | І. М. Pohrelyuk | Juozas Padgurskas | V. М. Hvozdetskyi | Khrystyna Zadorozna | H. V. Chumalo | О. Z. Student | I. V. Koval’chuk
Source: Coatings (article, 2023-02-08)
Field: Materials Science — Materials Chemistry

The Effect of Heat Treatment on the Structural-Phase State and Abrasive Wear Resistance of a Hard-Anodized Layer on Aluminum Alloy 1011 The aim of this study was to evaluate the effect of heat treatment on the phase composition, hardness, and abrasion wear resistance of hard-anodized layers (HAL) on 1011 aluminum alloy. X-ray diffraction analysis revealed the Al2O3·3H2O phase in the structure of HAL synthesized for 1 h. While in the heat-treated HAL, aluminum oxide phases of the α-Al2O3(amorphous) and γ-Al2O3(amorphous) types were found. Treatment at 400 °C for 1 h increased the HAL microhardness from 400 to 650 HV, and its abrasive wear resistance with fixed abrasive by up to 2.6 times. The ranking of various ways of hardening aluminum alloys relative to the D16 alloy showed that the abrasive wear resistance of heat-treated HAL is 20 times higher. Plasma electrolyte oxidation increased the abrasive wear resistance of the D16 alloy by 70–90 times, and its coating with high-speed oxygen fuel by 75–85 times. However, both methods are complex, energy-consuming, and require fine grinding of parts. Despite the lower wear resistance of HAL, their synthesis is cheaper and does not require the fine-tuning of parts. Moreover, despite the low hardness of HAL at present, hard anodizing is already commercially used to harden engine pistons, clamshell rotators, and pulleys. Abrasive ; Materials science ; Metallurgy ; Anodizing ; Alloy ; Indentation hardness ; Amorphous solid ; Abrasion (mechanical) ; Aluminium ; Hardening (computing) ; Coating ; Composite material ; Layer (electronics) ; Microstructure Anodic Oxide Films and Nanostructures ; Metal and Thin Film Mechanics ; Aluminum Alloys Composites Properties
Authors: Ankica Šarić | Ines Despotović
Source: Materials (article, 2023-07-05)
Field: Materials Science — Materials Chemistry

Hydrogen Bonds as Stability-Controlling Elements of Spherical Aggregates of ZnO Nanoparticles: A Joint Experimental and Theoretical Approach The effects of various organic additives, such as diethanolamine (DEA) and ethanolamine (EA), and variations in aging times on the formation and stability mechanisms of spherical aggregates of ZnO nanoparticles (NPs) prepared by using solvothermal synthesis were studied. The experimental results of the structural, morphological and optical properties monitored by using X-ray diffraction, field-emission scanning electron microscopy (FE-SEM) and UV-Vis spectroscopy were supported by quantum chemical calculations at the level of density functional theory (DFT). Understanding the mechanism of spherical ZnO aggregate formation and its stability by mimicking the processes at the computer level was achieved through theoretical simulations of the ZnO surface/additive interactions using (ZnO)<sub>36</sub>-DEA and (ZnO)<sub>36</sub>-EA models. The fine-tuned spherical aggregation of ZnO nanoparticles was driven by various interactions, in particular, strong O-H∙∙∙O and weak N-H∙∙∙O hydrogen bonds as controlling interactions. The calculated negative free release energy, ∆G*<sub>INT</sub>, indicates that the ZnO surface/additive interaction in diethanolamine media is a spontaneous exergonic process (∆G*<sub>INT</sub> = -7.73 kcal mol<sup>-1</sup>), whereas, in ethanolamine media, it is an unfavorable, slightly endergonic process (∆G*<sub>INT</sub> > 0). The presence of two strong O-H∙∙∙O hydrogen bonds and, at the same time, a weaker N-H∙∙∙O hydrogen bond is the key factor for the very good and long-term aggregate stability of ZnO NPs in DEA media. This integrated experimental-theoretical study highlights the stability and compactness of spherical ZnO aggregates of ZnO NPs, prepared in the presence of diethanolamine compared to ethanolamine media, and provides a promising method and flexible design of ZnO nanomaterials to improve their adsorptive and optical properties. Diethanolamine ; Hydrogen bond ; Materials science ; Chemical engineering ; Nanoparticle ; Ethanolamine ; Density functional theory ; Molecule ; Physical chemistry ; Nanotechnology ; Computational chemistry ; Chemistry ; Organic chemistry ZnO doping and properties ; Gas Sensing Nanomaterials and Sensors ; Copper-based nanomaterials and applications
Authors: Junkai Dong | Taige Wang | Tianle Wang | Tomohiro Soejima | Michael P. Zaletel | Ashvin Vishwanath | Daniel E. Parker
Source: arXiv (Cornell University) (preprint, 2023-11-09)
Field: Materials Science — Materials Chemistry

Anomalous Hall Crystals in Rhombohedral Multilayer Graphene I: Interaction-Driven Chern Bands and Fractional Quantum Hall States at Zero Magnetic Field Recent experiments on rhombohedral pentalayer graphene flakes with a substrate induced moiré potential have identified both Chern insulators and fractional Quantum Hall states in the absence of an applied magnetic field. Surprisingly, these states are observed in strong displacement fields where the effects of the moiré lattice are weak, and seem to be readily accessed without fine-tuning. To address these experimental puzzles we study an interacting model of electrons in this geometry, first within the self-consistent Hartree-Fock (SCHF) approximation. We find an isolated Chern band with Chern number $|C|=1$, that moreover is relatively flat and shows good quantum geometry. Exact diagonalization and density matrix renormalization group methods at fractional filling establish the presence of fractional quantum anomalous Hall (FQAH) states. The $|C|=1$ band in SCHF is remarkably robust to varying microscopic parameters, and is also found in the $N_L=4$ and $N_L=6$ layer systems. Remarkably, it appears stable even to switching off the moiré potential, pointing to spontaneous breaking of translation symmetry. We term this topological crystalline state the ``anomalous Hall crystal" (AHC), and argue that it constitutes a general mechanism for creating stable Chern bands in rhombohedral graphene. Our work elucidates the physics behind the recent rhombohedral pentalayer graphene observations, predicts the appearance of the same phase in other systems, and opens the door to studying the interplay between electronic topology and spontaneous translation symmetry breaking. Quantum Hall effect ; Condensed matter physics ; Physics ; Graphene ; Translational symmetry ; Fractional quantum Hall effect ; Quantum phases ; Quantum anomalous Hall effect ; Quantum mechanics ; Symmetry breaking ; Magnetic field ; Quantum spin Hall effect ; Quantum phase transition ; Phase transition Graphene research and applications ; Quantum and electron transport phenomena ; Topological Materials and Phenomena
Authors: Jiamin Tang | Sheng Zhang | Linzhou Li | Linbin Yao | Ronghu Zhang | Bing Yin | Jiangwei Zhang
Source: Dalton Transactions (article, 2023-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Influence of ligand substitution and the solvent effect on the structures and magnetic properties of dinuclear Dy<sub>2</sub> supramolecular architectures constructed with the bis-β-diketonate-Dy<sub>2</sub> building block as a metalloligand Based on the bis-β-diketonate-Dy<sub>2</sub> metalloligand [Dy<sub>2</sub>(pbth)<sub>4</sub>]·2Et<sub>3</sub>N (1, pbth = (3z,3'z)-4,4'-(1,3-phenylene)bis(1,1,1-trifluoro-4-hydroxybut-3-en-2-one)), six dinuclear complexes with eight-coordinated geometries were synthesized solvothermally through different capping N-donor coligands or solvent systems. These complexes are namely [Dy<sub>2</sub>(pbth)<sub>3</sub>(Phen)<sub>2</sub>]·2C<sub>2</sub>H<sub>5</sub>OH (2), [Dy<sub>2</sub>(pbth)<sub>3</sub>(BPhen)<sub>2</sub>]·2C<sub>2</sub>H<sub>5</sub>OH (3), [Dy<sub>2</sub>(pbth)<sub>3</sub>(Dppz)<sub>2</sub>]·2C<sub>2</sub>H<sub>5</sub>OH (4), [Dy<sub>2</sub>(pbth)<sub>3</sub>(Dppz)<sub>2</sub>]·2CH<sub>3</sub>OH (4a), [Dy<sub>2</sub>(pbth)<sub>3</sub>(4-Dmbp)<sub>2</sub>]·CH<sub>3</sub>OH·C<sub>2</sub>H<sub>5</sub>OH (5) and [Dy<sub>2</sub>(pbth)<sub>3</sub>(5-Dmbp)<sub>2</sub>]·CH<sub>3</sub>OH (6) (Phen = 1,10-phenanthroline, BPhen = 4,7-diphenyl-1,10-phenanthroline, dppz = dipyrido [3,2-<i>a</i>:2',3'-<i>c</i>] phenazine, 4-Dmbp = 4,4'-dimethyl-2,2'-bipyridyl, 5-Dmbp = 5,5'-dimethyl-2,2'-bipyridyl), respectively. In the synthetic processes of 2-6, one of four bis-β-diketonate ligands in the metalloligand is replaced by two capping N-donor coligands. The coordination geometries, metal distances and M-L-M torsion angles of the synthesized complexes are perceptibly fine-tuned by the modification of the capping N-donor coligands or the latticed solvent molecules. Systematic magnetic investigations indicate the different magnetic relaxation dynamics of 1-6. Complex 1 displays no characteristics of single-molecule magnets (SMMs), while complexes 2-6 exhibit SMM behaviours in the absence of a static magnetic field. Complexes 2 and 3 possess effective energy barriers (<i>U</i><sub>eff</sub>) of 110.18 (2) K and 133.21 (4) K, respectively. Theoretical analysis based on <i>ab initio</i> calculation provides some interpretations of experimental observation. Supramolecular chemistry ; Solvent ; Ligand (biochemistry) ; Crystallography ; Substitution (logic) ; Chemistry ; Materials science ; Crystal structure ; Organic chemistry ; Computer science Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Organic and Molecular Conductors Research
Authors: Md Arifuzzaman | Yan Zhao
Source: The Journal of Organic Chemistry (article, 2023-02-16)
Field: Chemistry — Spectroscopy

Selective Hydrolysis of Nonactivated Aryl Esters at pH 7 through Cooperative Catalysis Most reported artificial esterases only hydrolyze highly activated substrates. We here report synthetic catalysts that hydrolyze nonactivated aryl esters at pH 7, via cooperative action of a thiourea group that mimics the oxyanion hole of a serine protease and a nearby nucleophilic/basic pyridyl group. The molecularly imprinted active site distinguishes subtle structural changes in the substrate, including elongation of the acyl chain by two carbons or shift of a remote methyl group by one carbon. Chemistry ; Hydrolysis ; Aryl ; Catalysis ; Nucleophile ; Substrate (aquarium) ; Oxyanion hole ; Thiourea ; Paraoxon ; Organic chemistry ; Serine protease ; Protease ; Combinatorial chemistry ; Active site ; Enzyme Analytical Chemistry and Chromatography ; Analytical chemistry methods development ; Chemical Synthesis and Analysis
Authors: Oleg V. Manaenkov | Linda Zh. Nikoshvili | Alexey V. Bykov | Olga Kislitsa | Maxim Grigoriev | Mikhail G. Sulman | Valentina G. Matveeva | Lioubov Kiwi‐Minsker
Source: Molecules (article, 2023-12-15)
Field: Materials Science — Materials Chemistry

An Overview of Heterogeneous Catalysts Based on Hypercrosslinked Polystyrene for the Synthesis and Transformation of Platform Chemicals Derived from Biomass Platform chemicals, also known as chemical building blocks, are substances that serve as starting materials for the synthesis of various value-added products, which find a wide range of applications. These chemicals are the key ingredients for many fine and specialty chemicals. Most of the transformations of platform chemicals are catalytic processes, which should meet the requirements of sustainable chemistry: to be not toxic for humans, to be safe for the environment, and to allow multiple reuses of catalytic materials. This paper presents an overview of a new class of heterogeneous catalysts based on nanoparticles of catalytically active metals stabilized by a polymer matrix of hypercrosslinked polystyrene (HPS). This polymeric support is characterized by hierarchical porosity (including meso- and macropores along with micropores), which is important both for the formation of metal nanoparticles and for efficient mass transfer of reactants. The influence of key parameters such as the morphology of nanoparticles (bimetallic versus monometallic) and the presence of functional groups in the polymer matrix on the catalytic properties is considered. Emphasis is placed on the use of this class of heterogeneous catalysts for the conversion of plant polysaccharides into polyols (sorbitol, mannitol, and glycols), hydrogenation of levulinic acid, furfural, oxidation of disaccharides, and some other reactions that might be useful for large-scale industrial processes that aim to be sustainable. Some challenges related to the use of HPS-based catalysts are addressed and multiple perspectives are discussed. Catalysis ; Levulinic acid ; Polystyrene ; Heterogeneous catalysis ; Chemistry ; Polymer ; Chemical engineering ; Nanoparticle ; Bimetallic strip ; Speciality chemicals ; Organic chemistry ; Materials science ; Nanotechnology Covalent Organic Framework Applications ; Catalysis for Biomass Conversion ; Supercapacitor Materials and Fabrication