jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Arwa Alrooqi | Zahra M. Al-Amshany | Laila M. Al-Harbi | Tariq Altalhi | Moamen S. Refat | A.M. Hassanien | Gaber A. M. Mersal | A.A. Atta
Source: Coatings (article, 2022-05-23)
Field: Chemistry — Organic Chemistry

Spectroscopic and Physicochemical Studies on 1,2,4-Triazine Derivative A novel 5-(5-Bromo-2-hydroxybenzylidene)-6-oxo-3-phenyl-5,6-dihydro-1,2,4-triazine-2(1H)-carbothioamide (4) “compound 4” was synthesized. The chemical structure of compound 4 was confirmed with spectroscopic techniques. Thermal analysis (TGA/dTGA) studies were conducted for identifying the kinetic thermodynamic parameters and the thermal stability of the synthesized compound 4. Cyclic voltammetric studies were performed for recognizing electrochemical characteristics of the synthesized compound 4. The calculated highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), and the band gap were found to be −3.61, −5.32, and 1.97 eV, respectively. Using a diffused reflectance spectroscopy (DRS) technique, the estimated values of the optical band transitions of compound 4 in powder form were found to be 2.07 and 2.67 eV. The structural properties of thermally evaporated compound 4 thin films were analyzed using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. It was found that compound 4 has a triclinic crystal structure. The optical transitions and the optical dispersion factors of compound 4 thin films were investigated using a UV-Vis spectroscopy technique. From the UV-Vis spectroscopy technique, Egind=3.6 V was estimated for both the as-deposited and annealed thin films. For the as-deposited film, there were two photoluminescence (PL) emission peaks centered at 473 and 490 nm with a shoulder at 422 nm. For the annealed film at 423 K, there were five PL emission peaks centered at 274, 416, 439, 464, and 707 nm with a shoulder at 548 nm. The dark electrical conduction of compound 4 thin film was through a thermally activated process with activation energy equaling 0.88 eV. Triclinic crystal system ; HOMO/LUMO ; Photoluminescence ; Band gap ; Materials science ; Fourier transform infrared spectroscopy ; Analytical Chemistry (journal) ; Spectroscopy ; Thin film ; Scanning electron microscope ; Crystal structure ; Crystallography ; Chemistry ; Molecule ; Nanotechnology ; Optics ; Optoelectronics ; Organic chemistry Synthesis and Characterization of Heterocyclic Compounds ; Organic Electronics and Photovoltaics ; Conducting polymers and applications
Authors: Keuna Jeon | Justin Andrei Asuncion | Alexander L. Corbett | Tiange Yuan | Meera Patel | Nesha May Andoy | Christian Titus Kreis | Oleksandr Voznyy | Ruby May A. Sullan
Source: Nanomaterials (article, 2022-06-13)
Field: Materials Science — Surfaces, Coatings and Films

Buffer Components Incorporate into the Framework of Polyserotonin Nanoparticles and Films during Synthesis Polyserotonin nanoparticles (PSeNP) and films are bioinspired nanomaterials that have potential in biomedical applications and surface coatings. As studies on polyserotonin (PSe) nanoparticles and films are still in their infancy, synthetic pathways and material development for this new class of nanomaterial await investigation. Here, we sought to determine how different buffers used during the polymerization of serotonin to form nanoparticles and films impact the physicochemical properties of PSe materials. We show that buffer components are incorporated into the polymer matrix, which is also supported by density functional theory calculations. While we observed no significant differences between the elasticity of nanoparticles synthesized in the different buffers, the nanoscale surface properties of PSe films revealed dissimilarities in surface functional groups influenced by solvent molecules. Overall, the results obtained in this work can be used towards the rational design of PSe nanomaterials with tailored properties and for specific applications. Nanomaterials ; Nanoparticle ; Materials science ; Nanotechnology ; Polymer ; Nanoscopic scale ; Surface modification ; Buffer (optical fiber) ; Polymerization ; Chemical engineering ; Computer science ; Composite material Polymer Surface Interaction Studies ; Nanofabrication and Lithography Techniques ; Block Copolymer Self-Assembly
Authors: Lucca Kühner | Luca Sortino | Benjamin Tilmann | Thomas Weber | Kenji Watanabe | Takashi Taniguchi | Stefan A. Maier | Andreas Tittl
Source: arXiv (Cornell University) (preprint, 2022-10-20)
Field: Materials Science — Electronic, Optical and Magnetic Materials

High-Q nanophotonics over the full visible spectrum enabled by hexagonal boron nitride metasurfaces All-dielectric optical metasurfaces with high quality (Q) factors have so far been hampered by the lack of simultaneously lossless and high refractive index (RI) materials over the full visible spectrum. To achieve broad spectral coverage, the use of low-index materials is, in fact, unavoidable due to the inverse correlation between the band-gap energy (and therefore the optical losses) and the RI. However, for Mie resonant photonics, smaller RIs are associated with reduced Q factors and mode volume confinement. In this work, we leverage symmetry-broken bound states in the continuum (BICs) to efficiently suppress radiation losses from the low-index (n~2) van der Waals material hexagonal boron nitride (hBN), realizing metasurfaces with high-Q resonances over the complete visible spectrum. In particular, we analyze the rational use of low and high RI materials as resonator components and harness our insights to experimentally demonstrate sharp BIC resonances with Q factors above 300, spanning wavelengths between 400 nm and 1000 nm from a single hBN flake. Moreover, we utilize the enhanced electric near-fields to demonstrate second harmonic generation (SHG) with enhancement factors above 102. Our results provide a theoretical and experimental framework for the implementation of low RI materials as photonic media for metaoptics. Nanophotonics ; Materials science ; Refractive index ; Plasmon ; Visible spectrum ; Optoelectronics ; Photonics ; Dielectric ; Wavelength ; High-refractive-index polymer ; Optics ; Physics Metamaterials and Metasurfaces Applications ; Plasmonic and Surface Plasmon Research ; Advanced Antenna and Metasurface Technologies
Authors: Maria A. Herz | Kati Finzel | Michael Ruck
Source: Zeitschrift für anorganische und allgemeine Chemie (article, 2022-03-31)
Field: Chemistry — Inorganic Chemistry

Design of High‐Temperature Syntheses on the Example of the Heavy‐Atom Cluster Compound Sn[PtBi<sub>6</sub>I<sub>12</sub>] Abstract Investigations into potential topological materials yielded the new subiodide Sn[PtBi 6 I 12 ]. The combination of thermal analyses with phase analyses of the products of isothermal ex situ syntheses allowed the establishment of a complex high‐temperature synthesis protocol for the crystal growth of the target phase despite the lack of knowledge of the quaternary phase diagram. A special challenge was to prevent the formation of competing compounds of the solid solution series (Bi 2x Sn 1–3x )[PtBi 6 I 12 ] with x ≠0. Sn[PtBi 6 I 12 ] crystallizes, isostructural to Pb[PtBi 6 I 12 ], in the rhombohedral space group R with lattice parameters a =1583.2(2) pm and c =1089.70(10) pm. The compound consists of cuboctahedral [PtBi 6 I 12 ] 2− clusters and Sn 2+ cations in an octahedral coordination between the trigonal faces of two cluster units, thereby concatenating them into infinite linear chains. The chains are connected via Bi I inter‐cluster bridges, creating a high‐entropy variant of the NaCl structure type. Sn[PtBi 6 I 12 ] is a semiconductor with an experimental bandgap of 0.8(1) eV. Fully relativistic density functional theory calculations including an implementation of the bifunctional formalism for the exchange energy indicate a topologically trivial bandgap of 0.81 eV between bands that are dominated by contributions of bismuth and iodine. Isostructural ; Crystallography ; Bismuth ; Octahedron ; Band gap ; Cluster (spacecraft) ; Phase diagram ; Chemistry ; Atom (system on chip) ; Semiconductor ; Crystal structure ; Isothermal process ; Materials science ; Phase (matter) ; Thermodynamics ; Physics ; Organic chemistry Inorganic Chemistry and Materials ; Iron-based superconductors research ; Crystal Structures and Properties
Authors: Luigi Menduti | Clara Baldoli | Simone Manetto | Michael Bolte | Hans‐Wolfram Lerner | Giovanna Longhi | Claudio Villani | Emanuela Licandro | Matthias Wagner
Source: Angewandte Chemie (article, 2022-11-21)
Field: Chemistry — Organic Chemistry

(BO)<sub>2</sub>‐Doped Tetrathia[7]helicene: A Configurationally Stable Blue Emitter Abstract Helicenes combine two central themes in chemistry: extended π‐conjugation and chirality. Hetero‐atom doping preserves both characteristics and allows modulation of the electronic structure of a helicene. Herein, we report the (BO) 2 ‐doped tetrathia[7]helicene 1 , which was prepared from 2‐methoxy‐3,3′‐bithiophene in four steps. 1 is formally derived by substituting two (Mes)B−O moieties in place of (H)C=C(H) fragments in two benzene rings of the parent tetrathia[7]helicene. X‐ray crystallography revealed a dihedral angle of 50.26(9)° between the two terminal thiophene rings. The ( P )‐/( M )‐ 1 enantiomers were separated by chiral HPLC and are configurationally stable at room temperature. The experimentally determined enantiomerization barrier of 27.4±0.1 kcal mol −1 is lower than that of tetrathia[7]helicene (39.4±0.1 kcal mol −1 ). The circular dichroism spectra of ( P )‐ and ( M )‐ 1 show a perfect mirror‐image relationship. 1 is a blue emitter ( λ em =411 nm) with a photoluminescence quantum efficiency of Φ PL =6 % ( cf . tetrathia[7]helicene: λ em ≈405 nm, Φ PL =5 %). Helicene ; Chemistry ; Enantiomer ; Chirality (physics) ; Crystallography ; Circular dichroism ; Pentalene ; Thiophene ; Stereochemistry ; Molecule ; Organic chemistry ; Physics Synthesis and Properties of Aromatic Compounds ; Photochromic and Fluorescence Chemistry ; Photoreceptor and optogenetics research
Authors: Joanna Stachowska | Monika Gamża | Claire L. Mellor | Ella N. Gibbons | Marta J. Krysmann | Antonios Kelarakis | Elżbieta Gumieniczek–Chłopek | Tomasz Strączek | Cz. Kapusta | Anna Szwajca
Source: Preprints.org (preprint, 2022-01-10)
Field: Materials Science — Materials Chemistry

Carbon Dots/Iron Oxide Nanoparticles With Tuneable Composition and Properties We present a simple strategy to generate a family of carbon dot/iron oxide nanoparticles (C/Fe-NPs) that relies on the thermal decomposition of iron (III) acetylacetonate in the presence of a highly fluorescent carbon-rich precursor, while polyethylene glycol serves as the passivation agent. By varying the molar ratio of the reactants, a series of C/Fe-NPs have been synthesized with tuneable elemental composition in terms of C, H, O, N, Fe. The quantum yield is enhanced from 6% to 9% as the carbon content increases from 27% to 36%, while the room temperature saturation magnetization is improved from 4.1 emu/g to 17.7 emu/g as the iron content is enriched from 17 to 31%. In addition, the C/Fe-NPs show excellent antimicrobial properties, minimal cytotoxicity and demonstrate promising bioimaging capabilities, thus showing great potential for the development of advanced diagnostic tools. Carbon fibers ; Materials science ; Polyethylene glycol ; Thermal decomposition ; Nanoparticle ; Iron oxide ; Iron oxide nanoparticles ; Passivation ; Quantum dot ; Oxide ; Quantum yield ; Chemical engineering ; Decomposition ; Nanotechnology ; Molar ratio ; Nuclear chemistry ; Inorganic chemistry ; Fluorescence ; Chemistry ; Organic chemistry ; Metallurgy ; Catalysis Carbon and Quantum Dots Applications ; Graphene and Nanomaterials Applications ; Pineapple and bromelain studies
Authors: Mikus Puriņš | Jérôme Waser
Source: Angewandte Chemie (article, 2022-01-14)
Field: Chemistry — Organic Chemistry

Asymmetric Cyclopropanation and Epoxidation via a Catalytically Formed Chiral Auxiliary Abstract 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 ; Chemistry ; Catalysis ; Chiral auxiliary ; Combinatorial chemistry ; Organic chemistry ; Reagent Cyclopropane Reaction Mechanisms ; Asymmetric Hydrogenation and Catalysis ; Asymmetric Synthesis and Catalysis
Authors: Bo Peng | Jia‐Feng Zhou | Hui Chen | Meng Ding | Yi-Song Zhu | Belén Albela | Peng Wu | Laurent Bonneviot | Kun Zhang
Source: ChemRxiv (preprint, 2022-09-26)
Field: Materials Science — Materials Chemistry

Tetraalkoxysilane Assisted Self-Emulsification Templating for Mesoporous Silica Nanoparticles with Controlled Mesostructures Although mesoporous silica nanoparticles (MSNs) have been intensively investigated, their mesostructure and formation mechanism are still a topic of debate. Here, we demonstrate that the formation of MSNs is a result of dynamic two-level template collaborative self-assembly of microemulsion droplets and spherical micelles, whose surfaces are both partly covered by silicate species. The stability of microemulsion droplets spontaneously formed by water-surfactant-tetraalkoxysilanes (TAOS) ternary system determines the final morphology and particle size of MSNs, and we definitively confirms that the dendritic MSNs (DMSNs) with unique hierarchical pore structures is a metastable intermediate product, which could be kinetically transferred to regular MSNs undergoing a fast structural collapse of microemulsion droplets with the continuous consumption of TAOS. Our research further highlights the prominent role of self-emulsification of organic silane reagents in sol-gel chemistry to tune the morphology and structure of final products. Microemulsion ; Mesoporous silica ; Nanoparticle ; Nanotechnology ; Materials science ; Mesoporous material ; Chemical engineering ; Micelle ; Metastability ; Ternary operation ; Pulmonary surfactant ; Chemistry ; Organic chemistry ; Catalysis ; Computer science Mesoporous Materials and Catalysis ; Photonic Crystals and Applications ; Aerogels and thermal insulation
Authors: Ivona Krošl | Marta Košćak | Karla Ribičić | Mladen Žinić | Dragomira Majhen | Ksenija Božinović | Ivo Piantanida
Source: International Journal of Molecular Sciences (article, 2022-06-23)
Field: Chemistry — Organic Chemistry

Impact of the Histidine-Triazole and Tryptophan-Pyrene Exchange in the WHW Peptide: Cu(II) Binding, DNA/RNA Interactions and Bioactivity In three novel peptidoids based on the tryptophan-histidine-tryptophan (WHW) peptide, the central histidine was replaced by Ala-(triazole), and two derivatives also had one tryptophan replaced with pyrene-alkyls of different lengths and flexibility. Pyrene analogues show strong fluorescence at 480-500 nm, attributed to intramolecular exciplex formation with tryptophan. All three peptidoids bind Cu<sup>2+</sup> cation in water with strong affinity, with Trp- Ala-(triazole)-Trp binding comparably to the parent WHW, and the pyrene analogues even stronger, demonstrating that replacement of histidine with triazole in peptides does not hamper Cu<sup>2+</sup> coordination. The studied peptidoids strongly bind to ds-DNA and ds-RNA, whereby their complexes with Cu<sup>2+</sup> exhibit distinctively different interactions in comparison to metal-free analogues, particularly in the stabilization of ds-DNA against thermal denaturation. The pyrene peptidoids efficiently enter living cells with no apparent cytotoxic effect, whereby their red-shifted emission compared to the parent pyrene allows intracellular confocal microscopy imaging, showing accumulation in cytoplasmic organelles. However, irradiation with 350 nm light resulted in evident antiproliferative effect on cells treated with micromolar concentrations of the pyrene analogues, presumably attributed to pyrene-induced production of singlet oxygen and consecutive cellular damage. Pyrene ; Chemistry ; Tryptophan ; Histidine ; DNA ; Triazole ; RNA ; Peptide ; Biochemistry ; Combinatorial chemistry ; Organic chemistry ; Enzyme ; Gene ; Amino acid Click Chemistry and Applications ; Synthesis and Biological Evaluation ; Chemical Synthesis and Analysis
Authors: Shantanu Shukla | Dean A. A. Myles | M.J. Cuneo
Source: Scientific Reports (article, 2022-10-21)
Field: Materials Science — Materials Chemistry

Mapping periplasmic binding protein oligosaccharide recognition with neutron crystallography Numerous studies have shown how periplasmic binding proteins (PBPs) bind substrates with exquisite specificity, even distinguishing between sugar epimers and anomers, or structurally similar ions. Yet, marked substrate promiscuity is also a feature encoded in some PBPs. Except for three sub-Ångström crystal structures, there are no reports of hydrogen atom positions in the remaining (> 1000) PBP structures. The previous X-ray crystal structure of the maltodextrin periplasmic-binding protein from Thermotoga maritima (tmMBP) complexed with oligosaccharide showed a large network of interconnected water molecules stretching from one end of the substrate binding pocket to the other. These water molecules are positioned to form multiple hydrogen bonds, as well as forming interactions between the protein and substrate. Here we present the neutron crystal structure of tmMBP to a resolution of 2.1 Å. This is the first neutron crystal structure from the PBP superfamily and here we unambiguously identify the nature and orientation of the hydrogen bonding and water-mediated interactions involved in stabilizing a tetrasaccharide in the binding site. More broadly, these results demonstrate the conserved intricate mechanisms that underlie substrate-specificity and affinity in PBPs. Periplasmic space ; Thermotoga maritima ; Crystallography ; Hydrogen bond ; Chemistry ; Binding site ; Lyase ; Substrate (aquarium) ; Biochemistry ; Stereochemistry ; Molecule ; Biology ; Enzyme ; Escherichia coli Enzyme Structure and Function ; Protein Structure and Dynamics ; Porphyrin Metabolism and Disorders
Authors: Domingo González‐Arjona | Emilio Roldán González | Germán López-Pérez | Manuel María Domínguez Pérez | Marina Calero-Castillo
Source: Sensors (article, 2022-10-05)
Field: Chemistry — Physical and Theoretical Chemistry

Coulometer from a Digitally Controlled Galvanostat with Photometric Endpoint Detection In this work, a coulometer was developed from a digitally controlled galvanostat. A simple colorimeter based on a RGB LED was used as a light emitter coupled to light detectors, while light dependent resistance (LDR) and photodiodes have been developed as endpoint detectors. Both hardware and software have been adapted from the original galvanostat design. Regarding the hardware, new electrical signal conditioners (filters and voltage dividers) were included to optimize the working system. The software was developed based on an open source Arduino UNO microcontroller. The different variables that control the titration process are managed by an add-in module for Excel data acquisition software that is freely available. A study of the possible variables that influence the titration process has been carried out. The system was tested with two classical coulometric titrations such as iodometry (thiosulfate, ascorbic acid) and acid/base (potassium acid phthalate as standard). The developed system is versatile as different endpoint color indicators can be employed (starch and phenolphthalein for the investigated reactions). Different experimental arrangements have been studied: the nature of the electrodes (Pt, Ag), type of cells (two separate compartments or a single compartment), and light detectors (LDR, photodiode). The influence of several experimental parameters (both electrical, light, and integration time) was studied and chosen to obtain the best performance of the complete system. Reproducibility results below 1% can be obtained under controlled conditions. In the case of acid/base titrations, the presence of atmospheric carbon dioxide was detected, whose interference was mainly affected by the stirring rate and the titration time. Photodiode ; Microcontroller ; Software ; Computer science ; Materials science ; Computer hardware ; Optoelectronics Various Chemistry Research Topics ; Analytical Chemistry and Sensors ; Electrochemical Analysis and Applications
Authors: Qilin Wang | Yuehui Zhai | Danming Chao | Zheng Chen | Zhenhua Jiang
Source: Materials (article, 2022-12-21)
Field: Materials Science — Polymers and Plastics

Preparation and Electrochromic Properties of Benzodithiophene-Isoindigo Conjugated Polymers with Oligoethylene Glycol Side Chains Functional polymers featuring good processability in non-halogenated, benzene-free green solvents are highly desired due to health and environmental concerns. Herein, a series of novel D-A type conjugated polymers, PBDT-IIDs, are designed and successfully prepared by "green" functionalization of the polymers with highly hydrophilic, highly polar, highly flexible, and biocompatible oligoethylene glycol (OEG) side chains in order to improve the processability. These series polymers are named PBDT-IID2, PBDT-IID3, and PBDT-IID4, respectively, according to the number of oxygen atoms in the side chain. After confirmation by structural characterization, the basic properties of PBDT-IIDs are also investigated. With the increase in the OEG side chain length, the polymer PBDT-IID4 not only has good solubility in the halogen solvent chlorobenzene, but also exhibits excellent solubility in the green halogen-free solvent methyltetrahydrofuran (Me-THF). As a result, the green solvent Me-THF can also be applied to prepare PBDT-IIDs' electrochromic active layers, except for chlorobenzene and toluene. The electrochromism of PBDT IIDs under both positive and negative voltages has a practical application potential. The several controllable switches between dark green and khaki (0-0.6 V) are expected to show great potential in the field of military camouflage. Furthermore, according to the principle of red, green, and blue (RGB) mixing, light blue-green in the reduced state (-1.6 V) can be used in the preparation of complementary ECDs to provide one of the three primary colors (green). Side chain ; Materials science ; Polymer ; Conjugated system ; Polymer chemistry ; Electrochromism ; Solvent ; Solubility ; Chlorobenzene ; Organic chemistry ; Chemical engineering ; Chemistry ; Composite material Conducting polymers and applications ; Organic Electronics and Photovoltaics ; Transition Metal Oxide Nanomaterials