jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Jiankang Chen | Jie Liu | Wen Yang | Ying Pei
Source: Polymers (review, 2023-01-10)
Field: Materials Science — Biomaterials

Collagen and Silk Fibroin as Promising Candidates for Constructing Catalysts A catalyst determines the mechanism of an organic chemical reaction, thus enabling the commercially viable formation of desired material products. Biopolymers offer new opportunities for the construction of catalysts by virtue of their biocompatibility, environmental benignity, and sustainability, as well as their low cost. Biopolymers are especially useful as carriers and precursors in catalysis application. The employment of biocompatible and biosustainable collagen and silk fibroin materials will revolutionize state-of-the-art electronic devices and systems that currently rely on conventional technologies. In this review, we first consider the ordered hierarchical structure, origin, and processing methods of collagen and silk fibroin. Then, the unique advantages and applicability of collagen and silk fibroin for constructing catalysts are summarized. Moreover, a summary of the state-of-the-art design, fabrication, and application of collagen- and silk fibroin-based catalysts, as well as the application of collagen- and silk-based catalysts, is presented by focusing on their roles as carriers and precursors, respectively. Finally, challenges and prospects are assessed for the construction and development of collagen and silk fibroin-based catalysts. Fibroin ; SILK ; Catalysis ; Biocompatibility ; Materials science ; Nanotechnology ; Biocompatible material ; Polymer science ; Benignity ; Chemistry ; Chemical engineering ; Composite material ; Organic chemistry ; Biomedical engineering ; Engineering Silk-based biomaterials and applications ; Bone Tissue Engineering Materials ; Collagen: Extraction and Characterization
Authors: David M. Freire | Hannah M. Johnston | Katherine J. Smith | Kristof Pota | Magy A. Mekhail | Sugam Kharel | Kayla N. Green
Source: Inorganic Chemistry (article, 2023-09-20)
Field: Chemistry — Inorganic Chemistry

Hydrogen Peroxide Disproportionation Activity Is Sensitive to Pyridine Substitutions on Manganese Catalysts Derived from 12-Membered Tetra-Aza Macrocyclic Ligands The abundance of manganese in nature and versatility to access different oxidation states have made manganese complexes attractive as catalysts for oxidation reactions in both biology and industry. Macrocyclic ligands offer the advantage of substantially controlling the reactivity of the manganese center through electronic tuning and steric constraint. Inspired by the manganese catalase enzyme, a biological catalyst for the disproportionation of H<sub>2</sub>O<sub>2</sub> into water and O<sub>2</sub>, the work herein employs 12-membered tetra-aza macrocyclic ligands to study how the inclusion of and substitution to the pyridine ring on the macrocyclic ligand scaffold impacts the reactivity of the manganese complex as a H<sub>2</sub>O<sub>2</sub> disproportionation catalyst. Synthesis and isolation of the manganese complexes was validated by characterization using UV-vis spectroscopy, SC-XRD, and cyclic voltammetry. Potentiometric titrations were used to study the ligand basicity as well as the thermodynamic equilibrium with Mn(II). Manganese complexes were also produced in situ and characterized using electrochemistry for comparison to the isolated species. Results from these studies and H<sub>2</sub>O<sub>2</sub> reactivity showed a remarkable difference among the ligands studied, revealing instead a distinction in the reactivity regarding the number of pyridine rings within the scaffold. Moreover, electron-donating groups on the 4-position of the pyridine ring enhanced the reactivity of the manganese center for H<sub>2</sub>O<sub>2</sub> disproportionation, demonstrating a handle for control of oxidation reactions using the pyridinophane macrocycle. Chemistry ; Disproportionation ; Reactivity (psychology) ; Manganese ; Pyridine ; Catalysis ; Ligand (biochemistry) ; Hydrogen peroxide ; Redox ; Inorganic chemistry ; Medicinal chemistry ; Photochemistry ; Combinatorial chemistry ; Organic chemistry Metal-Catalyzed Oxygenation Mechanisms ; Metal complexes synthesis and properties ; Electrochemical Analysis and Applications
Authors: Yohei Sato | Ryohei Hayami | Kazuki Yamamoto | Takahiro Gunji
Source: Journal of Sol-Gel Science and Technology (article, 2023-10-28)
Field: Materials Science — Materials Chemistry

Preparation and properties of PDMS elastomer cross-linked with hydrolyzate of tetraethoxysilane, hexaethoxydisiloxane, and octaethoxytrisiloxane: influence of cross-linker structure Abstract Ethoxysilanes were hydrolyzed, and the resulting hydrolyzates were dimethylsilylated to produce Si–H terminated oligosiloxanes (CLs). These CLs were characterized using gel permeation chromatography, nuclear magnetic resonance, and Fourier-transform infrared spectroscopy. The results indicated the formation of highly condensed cyclic siloxanes, four-membered cyclic siloxanes, and linearly condensed cyclic siloxanes when derived from tetraethoxysilane, hexaethoxydisiloxane, and octaethoxytrisiloxane, respectively. The CLs were subsequently reacted with vinyl-terminated polydimethylsiloxane in the presence of the Karstedt catalyst to yield PDMS elastomers, which are comprised of di- and quadra-functional silicones. Tests for transmittance, thermal properties, tensile strength, and swelling in toluene were conducted to assess the impact of the molecular weight and microstructure of the CLs on the final products. As the number of silicon atoms in the ethoxysilanes increased, there was a rise in the secant modulus and a reduction in the degree of swelling. These findings suggest that the structure of PDMS elastomers can be tailored by varying the structure of the ethoxysilanes used as a cross-linking agent. Graphical Abstract Hydrosilylation ; Elastomer ; Gel permeation chromatography ; Materials science ; Polydimethylsiloxane ; Polymer chemistry ; Ultimate tensile strength ; Swelling ; Fourier transform infrared spectroscopy ; Chemical engineering ; Composite material ; Polymer ; Chemistry ; Organic chemistry ; Catalysis Silicone and Siloxane Chemistry ; Synthesis and properties of polymers ; Advanced Sensor and Energy Harvesting Materials
Authors: Anamar Blanes-Díaz | Mohammad Shohel | Natalie T. Rice | Ida Piedmonte | Morgan A. McDonald | Kaveh Jorabchi | Stosh A. Kozimor | Jeffery A. Bertke | May Nyman | Karah E. Knope
Source: Inorganic Chemistry (article, 2023-10-04)
Field: Chemistry — Inorganic Chemistry

Synthesis and Characterization of Cerium-Oxo Clusters Capped by Acetylacetonate Cerium-oxo clusters have applications in fields ranging from catalysis to electronics and also hold the potential to inform on aspects of actinide chemistry. Toward this end, a cerium-acetylacetonate (acac<sup>1-</sup>) monomeric molecule, Ce(acac)<sub>4</sub> (<b>Ce-1</b>), and two acac<sup>1-</sup>-decorated cerium-oxo clusters, [Ce<sub>10</sub>O<sub>8</sub>(acac)<sub>14</sub>(CH<sub>3</sub>O)<sub>6</sub>(CH<sub>3</sub>OH)<sub>2</sub>]·10.5MeOH (<b>Ce-10</b>) and [Ce<sub>12</sub>O<sub>12</sub>(OH)<sub>4</sub>(acac)<sub>16</sub>(CH<sub>3</sub>COO)<sub>2</sub>]·6(CH<sub>3</sub>CN) (<b>Ce-12</b>), were prepared and structurally characterized. The Ce(acac)<sub>4</sub> monomer contains Ce<sup>IV</sup>. Crystallographic data and bond valence summation values for the <b>Ce-10</b> and <b>Ce-12</b> clusters are consistent with both clusters having a mixture of Ce<sup>III</sup> and Ce<sup>IV</sup> cations. Ce L<sub>3</sub>-edge X-ray absorption spectroscopy, performed on <b>Ce-10</b>, showed contributions from both Ce<sup>III</sup> and Ce<sup>IV</sup>. The <b>Ce-10</b> cluster is built from a hexameric cluster, with six Ce<sup>IV</sup> sites, that is capped by two dimeric Ce<sup>III</sup> units. By comparison, <b>Ce-12</b>, which formed upon dissolution of <b>Ce-10</b> in acetonitrile, consists of a central decamer built from edge sharing Ce<sup>IV</sup> hexameric units, and two monomeric Ce<sup>III</sup> sites that are bound on the outer corners of the inner Ce<sub>10</sub> core. Electrospray ionization mass spectrometry data for solutions prepared by dissolving <b>Ce-10</b> in acetonitrile showed that the major ions could be attributed to Ce<sub>10</sub> clusters that differed primarily in the number of acac<sup>1-</sup>, OH<sup>1-</sup>, MeO<sup>1-</sup>, and O<sup>2-</sup> ligands. Small angle X-ray scattering measurements for <b>Ce-10</b> dissolved in acetonitrile showed structural units slightly larger than either Ce<sub>10</sub> or Ce<sub>12</sub> in solution, likely due to aggregation. Taken together, these results suggest that the acetylacetonate supported clusters can support diverse solution-phase speciation in organic solutions that could lead to stabilization of higher order cerium containing clusters, such as cluster sizes that are greater than the Ce<sub>10</sub> and Ce<sub>12</sub> reported herein. Cerium ; Chemistry ; Acetonitrile ; Crystallography ; Monomer ; Dissolution ; Electrospray ionization ; Molecule ; Cluster (spacecraft) ; Inorganic chemistry ; Ion ; Physical chemistry ; Organic chemistry ; Polymer Radioactive element chemistry and processing ; Lanthanide and Transition Metal Complexes ; Polyoxometalates: Synthesis and Applications
Authors: Samantha K. Samaniego Andrade | Lakshmi Shiva Shankar | I. Bakos | Szilvia Klébert | Róbert Kun | M. Mohai | Balázs Nagy | Krisztina László
Source: Nanomaterials (article, 2023-08-18)
Field: Materials Science — Electronic, Optical and Magnetic Materials

The Influence of Reduced Graphene Oxide on the Texture and Chemistry of N,S-Doped Porous Carbon. Implications for Electrocatalytic and Energy Storage Applications In this work, we study the influence of reduced graphene oxide (rGO) on the morphology and chemistry of highly porous N,S-doped carbon cryogels. Simultaneously, we propose an easily upscalable route to prepare such carbons by adding graphene oxide (GO) in as-received suspended form to the aqueous solution of the ι-carrageenan and urea precursors. First, 1.25-5 wt% GO was incorporated into the dual-doped polymer matrix. The CO<sub>2</sub>, CO, and H<sub>2</sub>O emitted during the thermal treatments resulted in the multifaceted modification of the textural and chemical properties of the porous carbon. This facilitated the formation of micropores through self-activation and resulted in a substantial increase in the apparent surface area (up to 1780 m<sup>2</sup>/g) and pore volume (up to 1.72 cm<sup>3</sup>/g). However, adding 5 wt% GO led to overactivation. The incorporated rGO has an ordering effect on the carbon matrix. The evolving oxidative species influence the surface chemistry in a complex way, but sufficient N and S atoms (ca. 4 and >1 at%, respectively) were preserved in addition to the large number of developing defects. Despite the complexity of the textural and chemical changes, rGO increased the electrical conductivity monotonically. In alkaline oxygen reduction reaction (ORR) tests, the sample with 1.25 wt% GO exhibited a 4e<sup>-</sup> mechanism and reasonable stability, but a higher rGO content gradually compromised the performance of the electrodes. The sample containing 5 wt% GO was the most sensitive under oxidative conditions, but after stabilization it exhibited the highest gravimetric capacitance. In Li-ion battery tests, the coulombic efficiency of all the samples was consistently above 98%, indicating the high potential of these carbons for efficient Li-ion insertion and reinsertion during the charge-discharge process, thereby providing a promising alternative for graphite-based anodes. The cell from the 1.25 wt% GO sample showed an initial discharge capacity of 313 mAh/g, 95.1% capacity retention, and 99.3% coulombic efficiency after 50 charge-discharge cycles. Graphene ; Oxide ; Chemical engineering ; Gravimetric analysis ; Aqueous solution ; Carbon fibers ; Materials science ; Texture (cosmology) ; Porosity ; Chemistry ; Inorganic chemistry ; Nanotechnology ; Composite material ; Organic chemistry ; Composite number Supercapacitor Materials and Fabrication ; Advancements in Battery Materials ; Advanced Battery Materials and Technologies
Authors: Rosalia Ferraro | Sergio Caserta
Source: Rheologica Acta (article, 2023-06-08)
Field: Chemistry — Organic Chemistry

SLE3S-water system: a linear rheological characterisation Abstract Surfactant-water mixtures display a complex rheological behaviour, with changes in parameters such as viscosity and moduli of several orders of magnitude as a consequence of phase changes, depending on their concentration and temperature: this criticism heavily affects different industrial processes. In our work, linear rheological behaviour of aqueous mixtures of a commercial anionic surfactant, sodium lauryl ether sulphate, is investigated in a range of temperature (30–60 °C) and surfactant concentration (20–72%wt) of technological relevance. Four phases with different texture are identified by polarised light microscopy: micellar, hexagonal, cubic and lamellar, all showing a shear-thinning behaviour. Rheological parameters of cubic phase show a net jump in a relatively narrow temperature range, suggesting a temperature-induced phase change. The systematic analysis of the rheological behaviour of this widely used surfactant system, reported here for the first time, can be of fundamental support for many industrial applications. Graphical Abstract Rheology ; Pulmonary surfactant ; Phase (matter) ; Viscosity ; Thermodynamics ; Chemical engineering ; Materials science ; Aqueous solution ; Shear thinning ; Atmospheric temperature range ; Chemistry ; Composite material ; Organic chemistry Surfactants and Colloidal Systems ; Enhanced Oil Recovery Techniques ; Electrostatics and Colloid Interactions
Authors: Bathini Veeraprakash | Gallelli Pratap | Nitin P. Lobo | K. V. Ramanathan | T. Narasimhaswamy
Source: ChemPhysChem (article, 2023-03-14)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Influence of the Thiophene Ring on the Molecular Order of Structurally Simple π‐Conjugated Smectogens: <sup>13</sup>C NMR Study Structurally simple rod-like π-conjugated mesogens with thiophene directly connected to phenyl, biphenyl, and fluorenone rings with terminal chains are synthesized respectively. The occurrence of smectic A/smectic C phases is concurred by a hot-stage optical polarising microscope (HOPM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The static 1D and 2D <sup>13</sup> C nuclear magnetic resonance (NMR) studies in the liquid crystalline phase are carried out to find the alignment-induced chemical shifts (AIS) and <sup>13</sup> C-<sup>1</sup> H dipolar couplings. The orientational order parameters of the mesogens determined from <sup>13</sup> C-<sup>1</sup> H dipolar couplings disclose that the long axis is not only collinear to the C3-C4 bond of the thiophene ring but also for the local axes of phenyl and biphenyl rings. For fluorenone-based mesogen, the molecular biaxiality is found to be high owing to the increased breadth of the molecule. The study unveils that the orientation of thiophene and the phenyl rings is similar in the current mesogens in stark contrast to mesogens, where thiophene is connected to phenyl rings through linking groups. Thiophene ; Mesogen ; Crystallography ; Liquid crystal ; Biphenyl ; Differential scanning calorimetry ; Conjugated system ; Ring (chemistry) ; Molecule ; Aromaticity ; Materials science ; Proton NMR ; Chemistry ; Side chain ; Stereochemistry ; Polymer ; Organic chemistry ; Liquid crystalline Liquid Crystal Research Advancements ; Synthesis and Properties of Aromatic Compounds ; Photochemistry and Electron Transfer Studies
Authors: Richard Y. Kong | Joseph B. Parry | Guy R. Anello | Matthew E. Ong | Kyle M. Lancaster
Source: Journal of the American Chemical Society (article, 2023-10-23)
Field: Chemistry — Organic Chemistry

Accelerating σ-Bond Metathesis at Sn(II) Centers Molecular main-group hydride catalysts are attractive as cheap and Earth-abundant alternatives to transition-metal analogues. In the case of the latter, specific steric and electronic tuning of the metal center through ligand choice has enabled the iterative and rational development of superior catalysts. Analogously, a deeper understanding of electronic structure-activity relationships for molecular main-group hydrides should facilitate the development of superior main-group hydride catalysts. Herein, we report a modular Sn-Ni bimetallic system in which we systematically vary the ancillary ligand on Ni, which, in turn, tunes the Sn center. This tuning is probed using Sn L<sub>1</sub> XAS as a measure of electron density at the Sn center. We demonstrate that increased electron density at Sn centers accelerates the rate of σ-bond metathesis, and we employ this understanding to develop a highly active Sn-based catalyst for the hydroboration of CO<sub>2</sub> using pinacolborane. Additionally, we demonstrate that engineering London dispersion interactions within the secondary coordination sphere of Sn allows for further rate acceleration. These results show that the electronics of main-group catalysts can be controlled without the competing effects of geometry perturbations and that this manifests in substantial reactivity differences. Chemistry ; Steric effects ; Bimetallic strip ; Catalysis ; Ligand (biochemistry) ; Hydride ; Electronic effect ; Hydroboration ; Center (category theory) ; Reactivity (psychology) ; Metathesis ; Coordination sphere ; Combinatorial chemistry ; Metal ; Computational chemistry ; Crystallography ; Stereochemistry ; Organic chemistry Organoboron and organosilicon chemistry ; Carbon dioxide utilization in catalysis ; Asymmetric Hydrogenation and Catalysis
Authors: Yongqi Liu | Ziyuan Li | Caifu Zhang | Biru Yang | Hua Ren
Source: Polymers (article, 2023-09-26)
Field: Materials Science — Polymers and Plastics

A Self-Healing Thermoset Epoxy Modulated by Dynamic Boronic Ester for Powder Coating Thermoset powder coatings exhibit distinctive characteristics such as remarkable hardness and exceptional resistance to corrosion. In contrast to conventional paints, powder coatings are environmentally friendly due to the absence of volatile organic compounds (VOCs). However, their irreversible cross-linking structures limit their chain segment mobility, preventing polymers from autonomously repairing cracks. Dynamic cross-linking networks have garnered attention for their remarkable self-healing capabilities, facilitated by rapid internal bond exchange. Herein, we introduce an innovative method for synthesizing thermoset epoxy containing boronic ester moieties which could prolong the life of the powder coating. The epoxy resin system relies on the incorporation of two curing agents: one featuring small-molecule diamines with boronic bonds and the other a modified polyurethane prepolymer. A state of equilibrium in mechanical properties was achieved via precise manipulation of the proportions of these agents, with the epoxy composite exhibiting a fracture stress of 67.95 MPa while maintaining a stable glass transition temperature (Tg) of 51.39 °C. This imparts remarkable self-healing ability to the coating surface, capable of returning to its original state even after undergoing 1000 cycles of rubbing (using 1200-grit abrasive paper). Furthermore, the introduction of carbon nanotube nanoparticles enabled non-contact sequential self-healing. Subsequently, we introduce this method into powder coatings of different materials. Therefore, this work provides a strategy to develop functional interior decoration and ensure its potential for broad-ranging applications, such as aerospace, transportation, and other fields. Thermosetting polymer ; Epoxy ; Materials science ; Coating ; Powder coating ; Prepolymer ; Self-healing ; Composite material ; Curing (chemistry) ; Polymer ; Polyurethane ; Glass transition Polymer composites and self-healing ; Polydiacetylene-based materials and applications ; Covalent Organic Framework Applications
Authors: Samiha Hossain | Airefetalo Sadoh | Nuggehalli M. Ravindra
Source: Material Science & Engineering International Journal (article, 2023-08-23)
Field: Materials Science — Materials Chemistry

Principles, properties and preparation of thermochromic materials The unique temperature-induced color changing properties of thermochromic materials make them of significant interest for applications in aerospace, anti-counterfeiting technology, construction, defense, drugs &amp; pharmaceuticals, electronics, energy, food &amp; agriculture, maintenance of infrastructure, materials processing &amp; storage, military technology, optoelectronics, packaging, sensors, smart displays, textiles, thermal storage and transportation. Thermochromism occurs due to the following characteristics: (a) phase transitions in a compound (e.g. leuco dyes); (b) changes in ligand geometry or the number of solvent molecules in the coordination sphere (e.g. transition metal complex that derives its color from crystal field effects) and (c) complex factors in multicomponent mixtures. Thermochromic materials can be divided into several categories depending on their material properties and operating conditions. In recent years, numerous techniques have been used to synthesize thermochromic materials for a variety of purposes and applications. This review summarizes the various mechanisms of thermochromism, their classification, preparation and applications and discusses future development trends. Thermochromism ; Materials science ; Nanotechnology ; Aerospace ; Electronics ; Smart material ; Chemistry ; Aerospace engineering ; Organic chemistry ; Engineering ; Physical chemistry Photochromic and Fluorescence Chemistry ; Polydiacetylene-based materials and applications ; Polyoxometalates: Synthesis and Applications
Authors: Pol Sallés | Pamela Machado | Pengmei Yu | Mariona Coll
Source: Chemical Communications (review, 2023-01-01)
Field: Materials Science — Materials Chemistry

Chemical synthesis of complex oxide thin films and freestanding membranes Oxides offer unique physical and chemical properties that inspire rapid advances in materials chemistry to design and nanoengineer materials compositions and implement them in devices for a myriad of applications. Chemical deposition methods are gaining attention as a versatile approach to develop complex oxide thin films and nanostructures by properly selecting compatible chemical precursors and designing an accurate cost-effective thermal treatment. Here, upon describing the basics of chemical solution deposition (CSD) and atomic layer deposition (ALD), some examples of the growth of chemically-deposited functional complex oxide films that can have applications in energy and electronics are discussed. To go one step further, the suitability of these techniques is presented to prepare freestanding complex oxides which can notably broaden their applications. Finally, perspectives on the use of chemical methods to prepare future materials are given. Membrane ; Nanotechnology ; Materials science ; Oxide ; Thin film ; Complex oxide ; Chemistry ; Metallurgy Electronic and Structural Properties of Oxides ; Semiconductor materials and devices ; Catalytic Processes in Materials Science