jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Subrat Kumar Barik | Chih‐Yuan Chen | Tzu‐Hao Chiu | Yu‐Rong Ni | Franck Gam | Isaac Chantrenne | Samia Kahlal | Jean‐Yves Saillard | C. W. Liu
Source: Communications Chemistry (article, 2022-11-18)
Field: Materials Science — Materials Chemistry

Surface modifications of eight-electron palladium silver superatomic alloys Atomically precise thiolate-protected coinage metal nanoclusters and their alloys are far more numerous than their selenium congeners, the synthesis of which remains extremely challenging. Herein, we report the synthesis of a series of atomically defined dithiophosph(in)ate protected eight-electron superatomic palladium silver nanoalloys [PdAg<sub>20</sub>{S<sub>2</sub>PR<sub>2</sub>}<sub>12</sub>], 2a-c (where R = O<sup>i</sup>Pr, a; O<sup>i</sup>Bu, b; Ph, c) via ligand exchange and/or co-reduction methods. The ligand exchange reaction on [PdAg<sub>20</sub>{S<sub>2</sub>P(O<sup>n</sup>Pr)<sub>2</sub>}<sub>12</sub>], 1, with [NH<sub>4</sub>{Se<sub>2</sub>PR<sub>2</sub>}<sub>12</sub>] (where R = O<sup>i</sup>Pr, or O<sup>n</sup>Pr) leads to the formation of [PdAg<sub>20</sub>{Se<sub>2</sub>P(O<sup>i</sup>Pr)<sub>2</sub>}<sub>12</sub>] (3) and [PdAg<sub>20</sub>{Se<sub>2</sub>P(O<sup>n</sup>Pr)<sub>2</sub>}<sub>12</sub>] (4), respectively. Solid state structures of 2a, 2b, 3 and 4 unravel different PdAg<sub>20</sub> metal frameworks from their parent cluster, originating from the different distributions of the eight-capping silver(I) atoms around a Pd@Ag<sub>12</sub> centered icosahedron with C<sub>2,</sub> D<sub>3,</sub> T<sub>h</sub> and T<sub>h</sub> symmetries, respectively. Surprisingly ambient temperature crystallization of the reaction product 3 obtained by the ligand exchange reaction on 1 has resulted in the co-crystallization of two isomers in the unit cell with overall T (3a) and C<sub>3</sub> (3b) symmetries, respectively. To our knowledge, this is the first ever characterized isomeric pair among the selenolate-protected NCs. Density functional theory (DFT) studies further rationalize the preferred geometrical isomerism of the PdAg<sub>20</sub> core. Nanoclusters ; Palladium ; Crystallization ; Ligand (biochemistry) ; Crystallography ; Metal ; Density functional theory ; Chemistry ; Cluster (spacecraft) ; Materials science ; Catalysis ; Nanotechnology ; Computational chemistry ; Organic chemistry Nanocluster Synthesis and Applications ; Neurological Complications and Syndromes ; Quantum Dots Synthesis And Properties
Authors: Rita Fonseca | Ricardo Vieira | Mariana Sardo | Ildefonso Marín-Montesinos | Luís Mafra
Source: The Journal of Physical Chemistry C (article, 2022-07-25)
Field: Chemistry — Spectroscopy

Exploring Molecular Dynamics of Adsorbed CO<sub>2</sub> Species in Amine-Modified Porous Silica by Solid-State NMR Relaxation Previous studies on CO<sub>2</sub> adsorbents have mainly addressed the identification and quantification of adsorbed CO<sub>2</sub> species in amine-modified porous materials. Investigation of molecular motion of CO<sub>2</sub> species in confinement has not been explored in depth yet. This work entails a comprehensive study of molecular dynamics of the different CO<sub>2</sub> species chemi- and physisorbed at amine-modified silica materials through the determination of the rotating frame spin-lattice relaxation times (<i>T</i> <sub>1ρ</sub>) by solid-state NMR. Rotational correlation times (τ<sub>C</sub>) were also estimated using spin relaxation models based on the Bloch, Wangsness, and Redfield and the Bloembergen-Purcell-Pound theories. As expected, the τ<sub>C</sub> values for the two physisorbed CO<sub>2</sub> species are considerably shorter (32 and 20 μs) than for the three identified chemisorbed CO<sub>2</sub> species (162, 62, and 123 μs). The differences in molecular dynamics between the different chemisorbed species correlate well with the structures previously proposed. In the case of the physisorbed CO<sub>2</sub> species, the τ<sub>C</sub> values of the CO<sub>2</sub> species displaying faster molecular dynamics falls in the range of viscous liquids, whereas the species presenting slower dynamics exhibit <i>T</i> <sub>1ρ</sub> and τ<sub>C</sub> values compatible with a CO<sub>2</sub> layer of weakly interacting molecules with the silica surface. The values for chemical shift anisotropy (CSA) and <sup>1</sup>H-<sup>13</sup>C heteronuclear dipolar couplings have also been estimated from <i>T</i> <sub>1ρ</sub> measurements, for each adsorbed CO<sub>2</sub> species. The CSA tensor parameters obtained from fitting the relaxation data agree with the experimentally measured CSA values, thus showing that the theories are well suited to study CO<sub>2</sub> dynamics in silica surfaces. Heteronuclear molecule ; Chemistry ; Chemical physics ; Relaxation (psychology) ; Molecular dynamics ; Adsorption ; Anisotropy ; Molecule ; Computational chemistry ; Physical chemistry ; Organic chemistry ; Physics Advanced NMR Techniques and Applications ; Advanced Condensed Matter Physics ; Zeolite Catalysis and Synthesis
Authors: Elisabetta Rosa | Enrico Gallo | Teresa Sibillano | Cinzia Giannini | Serena Rizzuti | Eliana Gianolio | Pasqualina Liana Scognamiglio | Giancarlo Morelli | Antonella Accardo | Carlo Diaferia
Source: Gels (article, 2022-12-16)
Field: Materials Science — Biomaterials

Incorporation of PEG Diacrylates (PEGDA) Generates Hybrid Fmoc-FF Hydrogel Matrices Generated by a hierarchical and multiscale self-assembling phenomenon, peptide-based hydrogels (HGs) are soft materials useful for a variety of applications. Short and ultra-short peptides are intriguing building blocks for hydrogel fabrication. These matrices can also be obtained by mixing low-molecular-weight peptides with other chemical entities (e.g., polymers, other peptides). The combination of two or more constituents opens the door to the development of hybrid systems with tunable mechanical properties and unexpected biofunctionalities or morphologies. For this scope, the formulation, the multiscale analysis, and the supramolecular characterization of novel hybrid peptide-polymer hydrogels are herein described. The proposed matrices contain the Fmoc-FF (N<sup>α</sup>-fluorenylmethyloxycarbonyl diphenylalanine) hydrogelator at a concentration of 0.5 wt% (5.0 mg/mL) and a diacrylate α-/ω-substituted polyethylene-glycol derivative (PEGDA). Two PEGDA derivatives, PEGDA 1 and PEGDA2 (mean molecular weights of 575 and 250 Da, respectively), are mixed with Fmoc-FF at different ratios (Fmoc-FF/PEGDA at 1/1, 1/2, 1/5, 1/10 mol/mol). All the multicomponent hybrid peptide-polymer hydrogels are scrutinized with a large panel of analytical techniques (including proton relaxometry, FTIR, WAXS, rheometry, and scanning electronic microscopy). The matrices were found to be able to generate mechanical responses in the 2-8 kPa range, producing a panel of tunable materials with the same chemical composition. The release of a model drug (Naphthol Yellow S) is reported too. The tunable features, the different topologies, and the versatility of the proposed materials open the door to the development of tools for different applicative areas, including diagnostics, liquid biopsies and responsive materials. The incorporation of a diacrylate function also suggests the possible development of interpenetrating networks upon cross-linking reactions. All the collected data allow a mutual comparison between the different matrices, thus confirming the significance of the hybrid peptide/polymer-based methodology as a strategy for the design of innovative materials. Self-healing hydrogels ; Polymer ; Polyethylene glycol ; PEG ratio ; Materials science ; Supramolecular chemistry ; Chemical engineering ; Rheometry ; Hydrogen bond ; Chemistry ; Nanotechnology ; Molecule ; Polymer chemistry ; Organic chemistry Supramolecular Self-Assembly in Materials ; Polydiacetylene-based materials and applications ; RNA Interference and Gene Delivery
Authors: G.J. Ayemi | S. Marcelin | Sandrine Thérias | Fabrice Leroux | Bernard Normand
Source: Applied Clay Science (article, 2022-03-30)
Field: Materials Science — Materials Chemistry

Synergy effect between layer double hydroxide (LDH) and EDDS for corrosion inhibition of carbon steel Carbon steel ; Chemistry ; Ethylenediamine ; Electrochemistry ; Hydroxide ; Corrosion ; Inorganic chemistry ; EDDS ; Polarization (electrochemistry) ; Chloride ; Carbon fibers ; Sodium hydroxide ; Materials science ; Composite number ; Electrode ; Organic chemistry ; Composite material ; Environmental chemistry Layered Double Hydroxides Synthesis and Applications ; Corrosion Behavior and Inhibition ; Magnesium Oxide Properties and Applications
Authors: Christian Bellacanzone | Jaume Ramon Otaegui | Jordi Hernando | Daniel Ruiz‐Molina | Claudio Roscini
Source: Advanced Optical Materials (article, 2022-03-20)
Field: Chemistry — Organic Chemistry

Tunable Thermofluorochromic Sensors Based on Conjugated Polymers Abstract Even though thermofluorochromic materials are eternal candidates for their use in multiple applications, they are still limited as they require complex synthetic strategies to accomplish tunable optical properties and/or provide optical changes only over a very wide temperature range. By taking advantage of the high sensitivity of the optical properties of conjugated polymers and oligomers to the external environment, herein phase change material (PCM)‐based thermofluorochromic mixtures are created, where the solid‐to‐liquid transition of the PCM host triggers a sharp fluorescence color change of the dispersed polymers/oligomers. Fluorophore conjugation length, concentration, and PCM nature can be used to vary the spectral properties of the resulting materials along the visible region, covering a large part of the CIE 1931 color space. For the preparation of functional devices, this behavior can be directly transferred to the solid state by soaking or printing cellulose papers with the obtained thermofluorochromic mixtures as well as by structuring them into solid lipid particles that can be dispersed within polymer matrices. The resulting materials show very promising features as thermal sensors and anticounterfeiting labels. Materials science ; Polymer ; Fluorophore ; Conjugated system ; Fluorescence ; Structuring ; Cellulose ; Nanotechnology ; Optoelectronics ; Chemical engineering ; Optics ; Composite material Polydiacetylene-based materials and applications ; Photochromic and Fluorescence Chemistry ; Luminescence and Fluorescent Materials
Authors: Xindi Liu | Huayan Yang | Yuxiang Chen | Ye Yang | Lionel Porcar | Aurel Rădulescu | Stefan Guldin | Rongchao Jin | Francesco Stellacci | Zhi Luo
Source: Angewandte Chemie International Edition (article, 2022-09-06)
Field: Materials Science — Materials Chemistry

Quantifying the Solution Structure of Metal Nanoclusters Using Small‐Angle Neutron Scattering Metal nanoclusters are a unique class of synthetic material, as their crystal structures can be resolved using X-ray diffraction, and their chemical formula can be precisely determinated from mass spectroscopy. However, a complete structure characterization by these two techniques is often a challenging task. Here, we utilize small-angle neutron scattering (SANS) to directly quantify the key structure parameters of a series of silver and gold nanoclusters in solution. The results not only correlate well to their crystallographic structures, but also allow the quantification of the counterions layer surrounding charged nanoclusters in solution. Furthermore, when combining with X-ray scattering, it is possible to estimate the molecular weight of both the metal core and the ligand shell of nanoclusters. This work offers an alternative characterization tool for nanoclusters without the requirement of crystallization or gas phase ionization. Nanoclusters ; Neutron scattering ; Materials science ; Counterion ; Scattering ; Neutron diffraction ; Characterization (materials science) ; Small-angle neutron scattering ; Crystallography ; Crystallization ; Small-angle X-ray scattering ; Chemical physics ; Crystal structure ; Nanotechnology ; Chemistry ; Optics ; Physics ; Ion ; Organic chemistry Nanocluster Synthesis and Applications ; Gold and Silver Nanoparticles Synthesis and Applications ; Advanced Nanomaterials in Catalysis
Authors: Mikus Puriņš | Jérôme Waser
Source: Angewandte Chemie International Edition (article, 2022-01-14)
Field: Chemistry — Organic Chemistry

Asymmetric Cyclopropanation and Epoxidation via a Catalytically Formed Chiral Auxiliary For the enantioselective diversification of a single starting material, a different chiral catalyst is usually required for each transformation. Herein, we extend the concept of catalytically formed chiral auxiliary from hydrogenation to the asymmetric cyclopropanation and epoxidation of tetra-substituted olefins, alleviating the need for different chiral catalysts in the alkene functionalization step. The chiral auxiliary is catalytically constructed from propargylic amines in a Pd-catalyzed enantioselective carboetherification step using a commercially available trifluoroacetaldehyde hemiacetal tether. The installed auxiliary is then controlling the stereochemistry of the cyclopropanation and the epoxidation using standard highly reactive reagents to give enantioenriched spirocyclic aminomethylcyclopropanols and α-amino-α-hydroxy ketones. Cyclopropanation ; Enantioselective synthesis ; Alkene ; Chiral auxiliary ; Catalysis ; Chemistry ; Reagent ; Organic chemistry ; Hemiacetal ; Combinatorial chemistry Cyclopropane Reaction Mechanisms ; Asymmetric Hydrogenation and Catalysis ; Asymmetric Synthesis and Catalysis
Authors: Tăchiță Vlad‐Bubulac | Corneliu Hamciuc | C. Rîmbu | Magdalena Aflori | Maria Butnaru | Alin Enache | Diana Serbezeanu
Source: Gels (article, 2022-07-28)
Field: Materials Science — Biomaterials

Fabrication of Poly(vinyl alcohol)/Chitosan Composite Films Strengthened with Titanium Dioxide and Polyphosphonate Additives for Packaging Applications Eco-innovation through the development of intelligent materials for food packaging is evolving, and it still has huge potential to improve food product safety, quality, and control. The design of such materials by the combination of biodegradable semi-synthetic polymers with natural ones and with some additives, which may improve certain functionalities in the targeted material, is continuing to attract attention of researchers. To fabricate composite films via casting from solution, followed by drying in atmospheric conditions, certain mass ratios of poly(vinyl alcohol) and chitosan were used as polymeric matrix, whereas TiO2 nanoparticles and a polyphosphonate were used as reinforcing additives. The structural confirmation, surface properties, swelling behavior, and morphology of the xerogel composite films have been studied. The results confirmed the presence of all ingredients in the prepared fabrics, the contact angle of the formulation containing poly(vinyl alcohol), chitosan, and titanium dioxide in its composition exhibited the smallest value (87.67°), whereas the profilometry and scanning electron microscopy enlightened the good dispersion of the ingredients and the quality of all the composite films. Antimicrobial assay established successful antimicrobial potential of the poly(vinyl alcoohol)/chitosan-reinforced composites films against Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. Cytotoxicity tests have revealed that the studied films are non-toxic, presented good compatibility, and they are attractive candidates for packaging applications. Vinyl alcohol ; Food packaging ; Chitosan ; Materials science ; Composite number ; Titanium dioxide ; Contact angle ; Polymer ; Chemical engineering ; Composite material ; Chemistry ; Food science Nanocomposite Films for Food Packaging ; Microplastics and Plastic Pollution ; biodegradable polymer synthesis and properties
Authors: Rubén D. Parra | Sławomir J. Grabowski
Source: International Journal of Molecular Sciences (article, 2022-09-25)
Field: Chemistry — Physical and Theoretical Chemistry

Enhancing Effects of the Cyano Group on the C-X∙∙∙N Hydrogen or Halogen Bond in Complexes of X-Cyanomethanes with Trimethyl Amine: CH3−n(CN)nX∙∙∙NMe3, (n = 0–3; X = H, Cl, Br, I) In this paper, density functional theory and wave function theory calculations are carried out to investigate the strength and nature of the intermolecular C-X∙∙∙N bond interaction as a function of the number of cyano groups, CN, in the X-bond donor while maintaining the X-bond acceptor as fixed. Specifically, complexes of X-cyanomethanes with trimethyl amine CH<sub>3-n</sub>(CN)<sub>n</sub>X∙∙∙NMe<sub>3</sub> (n = 0-3; X = H, Cl, Br, I) are used as model systems. Geometrical parameters and vibrational C-X-stretching frequencies as well as interaction energies are used as relevant indicators to gauge hydrogen or halogen bond strength in the complexes. Additional characteristics of interactions that link these complexes, i.e., hydrogen or halogen bonds, are calculated with the use of the following theoretical tools: the atoms in molecules (AIM) approach, the natural bond orbital (NBO) method, and energy decomposition analysis (EDA). The results show that, for the specified X-center, the strength of C-X∙∙∙N interaction increases significantly and in a non-additive fashion with the number of CN groups. Moreover, the nature (noncovalent or partly covalent) of the interactions is revealed via the AIM approach. Natural bond orbital ; Chemistry ; Hydrogen bond ; Halogen bond ; Halogen ; Intermolecular force ; Crystallography ; Non-covalent interactions ; Atoms in molecules ; Amine gas treating ; Bond strength ; Computational chemistry ; Acceptor ; Molecule ; Density functional theory ; Interaction energy ; Triple bond ; Bond energy ; Covalent bond ; Double bond ; Organic chemistry Crystallography and molecular interactions ; Molecular Spectroscopy and Structure ; Advanced Chemical Physics Studies
Authors: Han Xiao | Xiufang Liu | Yunzi Feng | Lin Zheng | Mouming Zhao | Mingtao Huang
Source: Biotechnology for Biofuels and Bioproducts (article, 2022-08-28)
Field: Materials Science — Biomaterials

Secretion of collagenases by Saccharomyces cerevisiae for collagen degradation Sufficient calcium and zinc ions are essential for active collagenase production by yeast. Collagenase secretion was increased by optimization of expression cassettes. Collagenase expression imposed metabolic burden and cofactor perturbations on yeast cells, which could be improved through metabolic engineering. Our work provides a useful way to produce collagenases for collagen resource utilization. Collagenase ; Yeast ; Biochemistry ; Secretion ; Saccharomyces cerevisiae ; Chemistry ; Microbial collagenase ; Enzyme biodegradable polymer synthesis and properties ; Fungal Biology and Applications ; Collagen: Extraction and Characterization
Authors: F. Arciprete | Jos E. Boschker | Stefano Cecchi | Eugenio Zallo | Valeria Bragaglia | Raffaella Calarco
Source: Advanced Materials Interfaces (article, 2022-02-06)
Field: Materials Science — Materials Chemistry

Hints for a General Understanding of the Epitaxial Rules for van der Waals Epitaxy from Ge‐Sb‐Te Alloys Abstract In this study, a generalized guideline is identified to predict the interaction between two‐dimensional (2D) layered materials and substrate surfaces. Additionally, the van der Waals (vdW) heterostructures commensurability, the phase formation and the strain relaxation are identified during interface growth. To achieve such a general overview, the case of Ge‐Sb‐Te (GST) alloys on InAs(111) is studied. In this system, low‐lattice mismatch conditions are fulfilled to avoid relaxation due to formation of misfit dislocations and allow to correctly identify vdW epitaxy. At the same time, the substrate can be efficiently prepared into self‐ and un‐passivated surfaces to clarify the role of the surface interaction. Furthermore, the GST epilayer exhibits two different highly ordered 2D structures and a three‐dimensional disordered structure, allowing to directly infer the nature of the epitaxy. This study opens the way for the design and mastering of vdW epitaxial growth of 2D heterostructures as well as hybrid 2D and non‐layered materials. Epitaxy ; Materials science ; Heterojunction ; van der Waals force ; Condensed matter physics ; Relaxation (psychology) ; Substrate (aquarium) ; Lattice (music) ; Chemical physics ; Nanotechnology ; Optoelectronics ; Chemistry ; Physics ; Layer (electronics) 2D Materials and Applications ; Topological Materials and Phenomena ; Advanced Thermoelectric Materials and Devices
Authors: Sulata K. Sahu | Dhruba Panthi | Ibrahim Soliman | Hai Feng | Yanhai Du
Source: Energies (article, 2022-05-12)
Field: Materials Science — Materials Chemistry

Fabrication and Performance of Micro-Tubular Solid Oxide Cells Solid Oxide Cells (SOC) are the kind of electrochemical devices that provide reversible, dual mode operation, where electricity is generated in a fuel cell mode and fuel is produced in an electrolysis mode. Our current work encompasses the design, fabrication, and performance analysis of a micro-tubular reversible SOC that is prepared through a single dip-coating technique with multiple dips using conventional materials. Electrochemical impedance and current-voltage responses were monitored from 700 to 800 °C. Maximum power densities of the cell achieved at 800, 750, and 700 °C, was 690, 546, and 418 mW cm−2, respectively. The reversible, dual mode operation of the SOC was evaluated by operating the cell using 50% H2O/H2 and ambient air. Accordingly, when the SOC was operated in the electrolysis mode at 1.3 V (the thermo-neutral voltage for steam electrolysis), current densities of −311, −487 and −684 mA cm−2 at 700, 750 and 800 °C, respectively, were observed. Hydrogen production rate was determined based on the current developed in the cell during the electrolysis operation. The stability of the cell was further evaluated by performing multiple transitions between fuel cell mode and electrolysis mode at 700 °C for a period of 500 h. In the stability test, the cell current decreased from 353 mA cm−2 to 243 mA cm−2 in the fuel cell mode operation at 0.7 V, while the same decreased from −250 mA cm−2 to −115 mA cm−2 in the electrolysis operation at 1.3 V. Electrolysis ; Materials science ; High-temperature electrolysis ; Solid oxide fuel cell ; Electrochemistry ; Fabrication ; Polymer electrolyte membrane electrolysis ; Electrolytic cell ; High-pressure electrolysis ; Voltage ; Electrode ; Nuclear engineering ; Analytical Chemistry (journal) ; Chemistry ; Electrical engineering ; Anode ; Electrolyte ; Engineering ; Chromatography Advancements in Solid Oxide Fuel Cells ; Electronic and Structural Properties of Oxides ; Catalysis and Oxidation Reactions