jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Haohai Xia | Xianglong Meng | Xingchao Jiang | Lilin Lu | Yanqun Wang
Source: Processes (article, 2023-05-04)
Field: Chemistry — Analytical Chemistry

Theoretical Investigation on the Catalytic Effect and Mechanism of Pure and Cu−Doped SBA−15 Molecular Sieves on the Decomposition of Dimethyl Sulfoxide The interaction mechanism between oil shale and catalyst is very important for the design and synthesis of related catalysis. In this work, dimethyl sulfoxide (DMSO) serves as a model molecule for organic sulfur compounds in oil shale to explore the catalytic effect and mechanism of the pure and transition metal Cu−doped SBA−15 molecular sieves regarding the decomposition of organic sulfur compounds in oil shale using the density functional theory (DFT) method. It is found that DMSO adsorption on both surfaces is primarily attributed to hydrogen bonding or the interaction between the S and O moieties within the molecule and the surface Cu atoms. The adsorption energies on both surfaces are indistinguishable; however, the Cu−doped SBA−15 shows enhanced catalytic activity in dissociation reactions. The Gibbs free energy changes for both possible reaction pathways of DMSO breaking C−S bonds on the pure SBA−15 surface are positive, and the activation energy barriers are as high as ~75 kcal/mol, indicating that the dissociation of C−S bonds in DMSO is unlikely to occur on this surface. In contrast, the Gibbs free energy change for the same reaction on the Cu−doped SBA−15 surface is negative, and the energy barrier is reduced by ~40 kcal/mol compared to that on the pure SBA−15 surface. Furthermore, the resulting methyl group is more likely to bond with the bridging oxygen atom. In addition, our research proposes that the dissociation of the C−H and C−S bonds of DMSO on the Cu−doped SBA−15 surface was competitive. These findings provide theoretical guidance for the development of highly efficient catalysts intended for the pyrolysis of oil shale under appropriate conditions. Catalysis ; Chemistry ; Adsorption ; Dissociation (chemistry) ; Gibbs free energy ; Molecule ; Density functional theory ; Physical chemistry ; Molecular sieve ; Sulfur ; Inorganic chemistry ; Computational chemistry ; Organic chemistry ; Thermodynamics Petroleum Processing and Analysis ; Hydrocarbon exploration and reservoir analysis ; Catalysis and Hydrodesulfurization Studies
Authors: Hannes Preißler-Kurzhöfer | A. L. Kolesnikov | Marcus Lange | Jens Möllmer | Oliver Erhart | Merten Kobalz | Seungtaik Hwang | Christian Chmelik | Harald Krautscheid | Roger Gläser
Source: Nanomaterials (article, 2023-02-02)
Field: Chemistry — Inorganic Chemistry

Hydrocarbon Sorption in Flexible MOFs—Part II: Understanding Adsorption Kinetics The rate of sorption of <i>n</i>-butane on the structurally flexible metal-organic framework [Cu<sub>2</sub>(H-Me-trz-ia)<sub>2</sub>], including its complete structural transition between a narrow-pore phase and a large-pore phase, was studied by sorption gravimetry, IR spectroscopy, and powder X-ray diffraction at close to ambient temperature (283, 298, and 313 K). The uptake curves reveal complex interactions of adsorption on the outer surface of MOF particles, structural transition, of which the overall rate depends on several factors, including pressure step, temperature, as well as particle size, and the subsequent diffusion into newly opened pores. With the aid of a kinetic model based on the linear driving force (LDF) approach, both rates of diffusion and structural transition were studied independently of each other. It is shown that temperature and applied pressure steps have a strong effect on the rate of structural transition and thus, the overall velocity of gas uptake. For pressure steps close to the upper boundary of the gate-opening, the rate of structural transition is drastically reduced. This feature enables a fine-tuning of the overall velocity of sorption, which can even turn into anti-Arrhenius behavior. Sorption ; Adsorption ; Diffusion ; Materials science ; Phase transition ; Thermodynamics ; Arrhenius equation ; Butane ; Phase (matter) ; Chemistry ; Chemical engineering ; Chemical physics ; Physical chemistry ; Activation energy ; Organic chemistry ; Catalysis Metal-Organic Frameworks: Synthesis and Applications ; Machine Learning in Materials Science ; Crystallography and molecular interactions
Authors: Mariano E. Brito | Sofia E. Mikhtaniuk | Igor M. Neelov | Oleg V. Borisov | Christian Holm
Source: International Journal of Molecular Sciences (article, 2023-02-01)
Field: Chemistry — Organic Chemistry

Implicit-Solvent Coarse-Grained Simulations of Linear–Dendritic Block Copolymer Micelles The design of nanoassemblies can be conveniently achieved by tuning the strength of the hydrophobic interactions of block copolymers in selective solvents. These block copolymer micelles form supramolecular aggregates, which have attracted great attention in the area of drug delivery and imaging in biomedicine due to their easy-to-tune properties and straightforward large-scale production. In the present work, we have investigated the micellization process of linear-dendritic block copolymers in order to elucidate the effect of branching on the micellar properties. We focus on block copolymers formed by linear hydrophobic blocks attached to either dendritic neutral or charged hydrophilic blocks. We have implemented a simple protocol for determining the equilibrium micellar size, which permits the study of linear-dendritic block copolymers in a wide range of block morphologies in an efficient and parallelizable manner. We have explored the impact of different topological and charge properties of the hydrophilic blocks on the equilibrium micellar properties and compared them to predictions from self-consistent field theory and scaling theory. We have found that, at higher degrees of branching in the corona and for short polymer chains, excluded volume interactions strongly influence the micellar aggregation as well as their effective charge. Copolymer ; Micelle ; Branching (polymer chemistry) ; Hydrodynamic radius ; Materials science ; Amphiphile ; Supramolecular chemistry ; Polymer ; Poloxamer ; Parallelizable manifold ; Chemical physics ; Polymer chemistry ; Nanotechnology ; Chemical engineering ; Chemistry ; Molecule ; Organic chemistry ; Computer science ; Aqueous solution ; Composite material Advanced Polymer Synthesis and Characterization ; Dendrimers and Hyperbranched Polymers ; Block Copolymer Self-Assembly
Authors: Tatiana G. Prokhorova | Денис В. Корчагин | G.V. Shilov | A. I. Dmitriev | Mikhail V. Zhidkov | Eduard B. Yagubskii
Source: Magnetochemistry (article, 2023-06-16)
Field: Materials Science — Electronic, Optical and Magnetic Materials

The Organic Ammonium Counterion Effect on Slow Magnetic Relaxation of the [Er(hfac)4]− Complexes The first mononuclear anionic erbium complex [Er(hfac)4]− (hfac = hexafluoroacetylacetone) with an organic ammonium cation [(CH3)4N+] as the counterion was synthesized and structurally and magnetically characterized. The coordination geometries around the Er ions are square antiprisms with pseudo-D4d symmetry. The complex shows distinct field-induced slow magnetization relaxation, which is described by a combination of Orbach (Ueff/kB~28.54(8) K.) and direct mechanisms. Quantum chemical calculations were performed to analyze the magnetic properties of the complex under consideration. Counterion ; Magnetic relaxation ; Relaxation (psychology) ; Chemistry ; Ion ; Magnetization ; Crystallography ; Ammonium ; Symmetry (geometry) ; Magnetic field ; Inorganic chemistry ; Physics ; Organic chemistry Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Electron Spin Resonance Studies
Authors: Stefano Kuschlan | Riccardo Chiarcos | Michele Laus | Francesc Pérez‐Murano | Jordi Llobet | Marta Fernández-Regúlez | Caroline Bonafos | Michele Perego | Gabriele Seguini | Marco De Michielis | G. Tallarida
Source: ACS Applied Materials & Interfaces (review, 2023-06-14)
Field: Materials Science — Materials Chemistry

Periodic Arrays of Dopants in Silicon by Ultralow Energy Implantation of Phosphorus Ions through a Block Copolymer Thin Film In this work, block copolymer lithography and ultralow energy ion implantation are combined to obtain nanovolumes with high concentrations of phosphorus atoms periodically disposed over a macroscopic area in a p-type silicon substrate. The high dose of implanted dopants grants a local amorphization of the silicon substrate. In this condition, phosphorus is activated by solid phase epitaxial regrowth (SPER) of the implanted region with a relatively low temperature thermal treatment preventing diffusion of phosphorus atoms and preserving their spatial localization. Surface morphology of the sample (AFM, SEM), crystallinity of the silicon substrate (UV Raman), and position of the phosphorus atoms (STEM- EDX, ToF-SIMS) are monitored during the process. Electrostatic potential (KPFM) and the conductivity (C-AFM) maps of the sample surface upon dopant activation are compatible with simulated <i>I</i>-<i>V</i> characteristics, suggesting the presence of an array of not ideal but working p-n nanojunctions. The proposed approach paves the way for further investigations on the possibility to modulate the dopant distribution within a silicon substrate at the nanoscale by changing the characteristic dimension of the self-assembled BCP film. Materials science ; Dopant ; Silicon ; Substrate (aquarium) ; Crystallinity ; Ion implantation ; Optoelectronics ; Raman spectroscopy ; Epitaxy ; Nanotechnology ; Doping ; Analytical Chemistry (journal) ; Ion ; Composite material ; Optics ; Layer (electronics) ; Organic chemistry Block Copolymer Self-Assembly ; Nanopore and Nanochannel Transport Studies ; Organic Electronics and Photovoltaics
Authors: Yulia O. Edilova | Ekaterina A. Osipova | Павел А. Слепухин | В. И. Салоутин | Денис Н. Бажин
Source: International Journal of Molecular Sciences (article, 2023-09-18)
Field: Chemistry — Organic Chemistry

Exploring Three Avenues: Chemo- and Regioselective Transformations of 1,2,4-Triketone Analogs into Pyrazoles and Pyridazinones A convenient approach to substituted pyrazoles and pyridazinones based on 1,2,4-triketones is presented. Chemo- and regiocontrol in condensations of <i>t</i>-Bu, Ph-, 2-thienyl-, and CO<sub>2</sub>Et-substituted 1,2,4-triketone analogs with hydrazines are described. The direction of preferential nucleophilic attack was shown to be switched depending on the substituent nature in triketone as well as the reaction conditions. The acid and temperature effects on the selectivity of condensations were revealed. Regiochemistry of heterocyclic core formation was confirmed by NMR and XRD studies. The facile construction of heterocyclic motifs bearing acetyl and (or) carbethoxy groups suggests them as promising mono- or bifunctional building blocks for subsequent transformations. Regioselectivity ; Bifunctional ; Chemistry ; Substituent ; Nucleophile ; Selectivity ; Stereochemistry ; Medicinal chemistry ; Organic chemistry ; Catalysis Synthesis and Biological Evaluation ; Synthesis and Reactions of Organic Compounds ; Bioactive Compounds and Antitumor Agents
Authors: Sheemol Valayampillil Narayanan | Muthusundar Kumar | Valan R. Gnanaraj | Sruthi C. Rajan | Viji Selvaraj | Solaiappan Ananthakumar
Source: MedComm – Biomaterials and Applications (article, 2023-01-27)
Field: Chemistry — Inorganic Chemistry

2‐Hydroxy‐1,4‐naphthoquinone [Lawsone] integrated rare‐earth hybrid materials as biocompatible UV/IR filter agents Abstract UV filter agents are essential ingredients in cosmetics and fabrics for rendering the property of protection from harmful UV radiation. The focus of this research was on the development of biocompatible hybrid UV/IR filter agents through sol–gel processing of nano‐sized lanthanum titanate, zirconate, and phosphate‐based rare‐earth materials. 2‐Hydroxy‐1,4‐naphthoquinone (Lawsone) is an ideal candidate, owing to its biocompatibility, for treating the sol of the rare‐earth systems to produce inorganic‐organic hybrids with classical orange shades. The rare‐earth hybrids were characterized by X‐Ray diffraction, dynamic light scattering, fourier transform infrared spectroscopy, scanning electron microscopy, UV‐Vis, photo‐luminescence, and Near Infrared (NIR) spectroscopy. The results of characterization indicated that the hybrids offer &gt;90% of NIR reflectance in the wavelength region from 700 to 1100 nm. They also exhibited excellent shielding in UV‐A and UV‐B regions, thus qualifying them as cool colors with useful optical as well as heat management characteristics. The sun protection factor calculated by optical density measurements showed that the synthesized hybrids have potential applications as UV filter agents in sunscreen lotions. The cell viability analyzed by the MTT (4,5‐dimethylthiazol‐2‐yl)−2,5‐diphenyltetrazolium bromide) assay affirmed the biocompatibility of the hybrids as none of the systems was found cytotoxic. This study was devoted to exploring the beneficial properties of rare‐earth‐based hybrid systems in pharmacological applications. Biocompatibility ; Materials science ; Lawsone ; Luminescence ; Hybrid material ; Stannate ; Nanomaterials ; Nuclear chemistry ; Nanotechnology ; Chemical engineering ; Chemistry ; Optoelectronics ; Organic chemistry Pigment Synthesis and Properties ; Skin Protection and Aging ; Nanoplatforms for cancer theranostics
Authors: Shan Gao | Yutaka Miura | Akira Sumiyoshi | Satoshi Ohno | K. Ogata | Takahiro Nomoto | Makoto Matsui | Yuto Honda | Minoru Suzuki | Megumi Iiyama | Kensuke Osada | Ichio Aoki | Nobuhiro Nishiyama
Source: Advanced Science (article, 2023-11-29)
Field: Materials Science — Biomaterials

Self‐Folding Macromolecular Drug Carrier for Cancer Imaging and Therapy Nano-sized contrast agents (NCAs) hold potential for highly specific tumor contrast enhancement during magnetic resonance imaging. Given the quantity of contrast agents loaded into a single nano-carrier and the anticipated relaxation effects, the current molecular design approaches its limits. In this study, a novel molecular mechanism to augment the relaxation of NCAs is introduced and demonstrated. NCA formation is driven by the intramolecular self-folding of a single polymer chain that possesses systematically arranged hydrophilic and hydrophobic segments in water. Utilizing this self-folding molecular design, the relaxivity value can be elevated with minimal loading of gadolinium complexes, enabling sharp tumor imaging. Furthermore, the study reveals that this NCA can selectively accumulate into tumor tissues, offering effective anti-tumor results through gadolinium neutron capture therapy. The efficacy and versatility of this self-folding molecular design underscore its promise for cancer diagnosis and treatment. Folding (DSP implementation) ; Gadolinium ; Macromolecule ; Relaxation (psychology) ; Molecular imaging ; Nanotechnology ; Cancer therapy ; Biophysics ; Magnetic resonance imaging ; Drug delivery ; Materials science ; Polymer ; Chemistry ; Nuclear magnetic resonance ; Cancer ; Medicine ; Organic chemistry ; Biochemistry ; In vivo Nanoparticle-Based Drug Delivery ; Nanoplatforms for cancer theranostics ; Supramolecular Chemistry and Complexes
Authors: Jesus Hernandez | Alex J. Robb | Savannah Servera | Nanor Bedrosian | Osma Gomez | Zachary A. Duca | Michael B. Thomas | Daniel Tamae | Paula L. Fischhaber | Simon J. Garrett | Patrick A. Ward | Joseph A. Teprovich
Source: ACS Applied Nano Materials (article, 2023-11-06)
Field: Materials Science — Materials Chemistry

Synthesis and Characterization of Amorphous Lawsone Polymer Dots for Fluorescent Applications In this work, a two-step hydrothermal/solvothermal process was developed to generate highly fluorescent lawsone polymer dots (LPDs) utilizing an inexpensive and abundant starting material, 2-hydroxy-1,4-napththoquinone (lawsone). This hydrothermal/solvothermal process produces LPDs that have excitation independent emission with well-defined electronic transitions. This two-step protocol provides a straightforward approach to remove unwanted small molecular fluorescence, which has plagued carbon dot systems, without the need for advanced chromatographic purification methods or steps. A series of spectroscopic, electrochemical, and theoretical experiments suggest that this process proceeds via a sequential dehydration and dehydrogenation pathway to cross-link the lawsone into a carbon dot structure. This polymerization process helps to stabilize and favor certain electronic transitions inherently present in the lawsone monomer. The generation of the LPDs results in a 2 order of magnitude increase in the emission intensity and a quantum yield of 37%. This behavior is likely the result of the cross-linked structure shielding these electronic states from deactivation caused by nonradiative processes such as vibrational coupling and excited state quenching from thermal deactivation and solvent collisions. This finding is consistent with a cross-linked enhanced emission (CEE) mechanism, as previously observed for other similar systems. The LPDs were then incorporated into a TiO<sub>2</sub> photoanode and utilized as a photosensitizer in a dye-sensitized solar cell (DSSC) which showed an enhancement in photocurrent density over pure TiO<sub>2</sub>. We also prepared a derivative of the LPDs utilizing a diethylene triamine additive (nitrogen-doped lawsone polymer dots (N-LPDs)) using the same two-step protocol and demonstrated its potential as a fluorescence microscopy dye for imaging MDA-MB-231 cancer cells. Lawsone ; Materials science ; Quantum dot ; Photochemistry ; Polymer ; Polymerization ; Nanotechnology ; Chemical engineering ; Chemistry ; Organic chemistry Carbon and Quantum Dots Applications ; Luminescence and Fluorescent Materials ; Organic Light-Emitting Diodes Research
Authors: Ina Mishra | Meredith Garrett | Stephen H. Curry | Jeffrey Taylor Jameson | Michail Kastellorizios
Source: International Journal of Molecular Sciences (article, 2023-08-30)
Field: Materials Science — Biomaterials

Effect of Composition and Size on Surface Properties of Anti-Cancer Nanoparticles Liposomal formulations offer significant advantages as anticancer drug carriers for targeted drug delivery; however, due to their complexity, clinical translation has been challenging. In addition, liposomal product manufacturing has been interrupted in the past, as was the case for Doxil<sup>®</sup> (doxorubicin hydrochloride liposome injection). Here, interfacial tension (IFT) measurements were investigated as a potential physicochemical characterization tool to aid in liposomal product characterization during development and manufacturing. A pendant drop method using an optical tensiometer was used to measure the interfacial tension of various analogues of Doxil<sup>®</sup> liposomal suspensions in air and in dodecane. The effect of liposome concentration, formulation (PEG and cholesterol content), presence of encapsulated drug, as well as average particle size was analyzed. It was observed that Doxil<sup>®</sup> analog liposomes demonstrate surfactant-like behavior with a sigmoidal-shape interfacial tension vs. concentration curve. This behavior was heavily dependent on PEG content, with a complete loss of surfactant-like behavior when PEG was removed from the formulation. In addition to interfacial tension, three data analyses were identified as able to distinguish between formulations with variations in PEG, cholesterol, and particle size: (i) polar and non-polar contribution to interfacial tension, (ii) liposomal concentration at which the polar and non-polar components were equal, and (iii) rate of interfacial tension decay after droplet formation, which is indicative of how quickly liposomes migrate from the bulk of the solution to the surface. We demonstrate for the first time that interfacial tension can be used to detect certain liposomal formulation changes, such as PEG content, encapsulated drug presence, and size variability, and may make a useful addition to physicochemical characterization during development and manufacturing of liposomal products. Surface tension ; Liposome ; Pulmonary surfactant ; Particle size ; PEG ratio ; Materials science ; Drop (telecommunication) ; Nanoparticle ; Drug delivery ; Chromatography ; Chemistry ; Chemical engineering ; Nanotechnology ; Thermodynamics ; Biochemistry ; Physical chemistry Nanoparticle-Based Drug Delivery ; Characterization and Applications of Magnetic Nanoparticles ; Inhalation and Respiratory Drug Delivery
Authors: Qi Guo | Behnam Ghalei | Detao Qin | Daizu Mizutani | Ikumi Joko | Habib Al-Aziz | Tomohiro Higashino | Masateru Ito | Hiroshi Imahori | Easan Sivaniah
Source: Chemical Communications (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

Graphene oxide-fullerene nanocomposite laminates for efficient hydrogen purification Graphene oxide (GO) with its unique two-dimensional structure offers an emerging platform for designing advanced gas separation membranes that allow for highly selective transport of hydrogen molecules. Nevertheless, further tuning of the interlayer spacing of GO laminates and its effect on membrane separation efficiency remains to be explored. Here, positively charged fullerene C<sub>60</sub> derivatives are electrostatically bonded to the surface of GO sheets in order to manipulate the interlayer spacing between GO nanolaminates. The as-prepared GO-C<sub>60</sub> membranes have a high H<sub>2</sub> permeance of 3370 GPU (gas permeance units) and an H<sub>2</sub>/CO<sub>2</sub> selectivity of 59. The gas separation selectivity is almost twice that of flat GO membranes because of the role of fullerene. Permeance ; Graphene ; Selectivity ; Membrane ; Oxide ; Fullerene ; Materials science ; Gas separation ; Nanocomposite ; Hydrogen ; Chemical engineering ; Nanotechnology ; Chemistry ; Organic chemistry ; Catalysis Graphene research and applications ; Membrane Separation and Gas Transport ; Membrane Separation Technologies
Authors: Myrat Kurbanov | Zachary J. Kirsch | Jithu Krishna | Ranit Dutta | Richard W. Vachet | S. Thayumanavan
Source: Bioconjugate Chemistry (article, 2023-05-23)
Field: Chemistry — Organic Chemistry

Multisite Labeling of Proteins Using the Ligand-Directed Reactivity of Triggerable Michael Acceptors Targeted modification of endogenous proteins without genetic manipulation of protein expression machinery has a range of applications from chemical biology to drug discovery. Despite being demonstrated to be effective in various applications, target-specific protein labeling using ligand-directed strategies is limited by stringent amino acid selectivity. Here, we present highly reactive ligand-directed triggerable Michael acceptors (LD-TMAcs) that feature rapid protein labeling. Unlike previous approaches, the unique reactivity of LD-TMAcs enables multiple modifications on a single target protein, effectively mapping the ligand binding site. This capability is attributed to the tunable reactivity of TMAcs that enable the labeling of several amino acid functionalities via a binding-induced increase in local concentration while remaining fully dormant in the absence of protein binding. We demonstrate the target selectivity of these molecules in cell lysates using carbonic anhydrase as the model protein. Furthermore, we demonstrate the utility of this method by selectively labeling membrane-bound carbonic anhydrase XII in live cells. We envision that the unique features of LD-TMAcs will find use in target identification, investigation of binding/allosteric sites, and studying membrane proteins. Chemistry ; Allosteric regulation ; Carbonic anhydrase ; Ligand (biochemistry) ; Carbonic anhydrase II ; Target protein ; Reactivity (psychology) ; Biochemistry ; Small molecule ; Chemical biology ; Combinatorial chemistry ; Amino acid ; Drug discovery ; Enzyme ; Computational biology ; Gene ; Receptor ; Biology Click Chemistry and Applications ; Chemical Synthesis and Analysis ; Monoclonal and Polyclonal Antibodies Research