jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Marisa Poveda
Source: USF Scholarship Repository (University of San Francisco) (article, 2020-01-01)
Field: Materials Science — Materials Chemistry

An Investigation of Antenna, Ligand Side-chain, and Metal Ion Effects on the Optical and MRI Properties of Bimodal Lanthanide (III) Complexes Magnetic Resonance Imaging (MRI) is a leading anatomical imaging modality for disease diagnosis. With the aid of Gd3+ based contrast agents, high resolution images of biological structures can be obtained. However, there is an increased need for contrast agents that are responsive to specific analytes and chemical environments. Paramagnetic Chemical Exchange Saturation Transfer (PARACEST) agents that utilize a paramagnetic lanthanide ion chelated with a ligand have shown great promise in this area. Lanthanide ions also possess luminescence properties that do not suffer from common limitations of conventional optical imaging agents such as autofluorescence and photobleaching. The projects described in this thesis aim to capitalize on the dual MRI and optical characteristics of lanthanide ions through the synthesis and characterization of a series of bimodal Eu3+ and Tb3+ complexes. Chapter one contains an overview of lanthanide complexes, MRI, and optical imaging. Chapter two details a study on the effect of quinoline-amide substituent position on the optical properties and stabilities of a library of Eu3+ complexes. In chapter three the effect of varying side-chain identities of Tb3+ and Eu3+ complexes is investigated. The results obtained from these projects indicate that minor changes in ligand structure can have a significant impact on the imaging properties and stabilities of these lanthanide complexes. This insight can be applied towards further optimization of the MRI and optical properties of bimodal Ln(III) complexes. Lanthanide ; Ligand (biochemistry) ; Metal ; Chain (unit) ; Ion ; Materials science ; Antenna (radio) ; Metal ions in aqueous solution ; Chemistry ; Crystallography ; Physics ; Computer science ; Metallurgy ; Organic chemistry ; Telecommunications Lanthanide and Transition Metal Complexes ; Electron Spin Resonance Studies ; Advanced MRI Techniques and Applications
Authors: Adhi Laksana Anugerah
Source: Hokkaido University Collection of Scholarly and Academic Papers (Hokkaido University) (article, 2020-09-25)
Field: Chemistry — Organic Chemistry

Cyclic aminals from aldehydes and “roofed” mono-N-sulfonyl cis-diamines A most popular strategy for optical resolution (resolution of enantiomers) is based on the different physical properties of diastereomers.New mono-N-sulfonyl cis-diamine reagents were created as chiral derivatizing reagents for racemic aldehydes in this research.Racemic aldehydes are converted into mixture of diastereomers by using the new "roofed" cis-diamine reagents.Most of resulting five-membered diastereomeric aminals are stable on silica-gel TLC plate and well separated by silica-gel chromatography.The absolute configuration of aldehyde moiety in each separated diastereomer is determined by twodimensional NMR analyses.The new reagents react smoothly with aldehydes under mild and neutral condition. Sulfonyl ; Chemistry ; Organic chemistry Sulfur-Based Synthesis Techniques ; Synthesis and Catalytic Reactions ; Chemical Synthesis and Reactions
Authors: Aleš Stýskalík | Imène Kordoghli | Claude Poleunis | Arnaud Delcorte | Z. Moravec | Lucie Šimoníková | Viktor Kanický | Carmela Aprile | Luca Fusaro | Damien P. Debecker
Source: ChemRxiv (preprint, 2020-05-22)
Field: Materials Science — Materials Chemistry

Ethanol Dehydration over Hybrid Mesoporous Aluminosilicate Catalysts Obtained in One Pot by Non-Hydrolytic Sol-Gel Ethanol dehydration is effectively catalyzed by solid acids, such as HZSM-5, alumina, or silica-alumina. In these catalysts, the amount, nature, and strength of acid sites is believed to determine catalyst activity and stability. However, surface hydrophilicity or hydrophobicity can be suggested as another decisive catalyst property that can directly influence performance. For example, a more hydrophobic surface might be beneficial in repelling the co-product of the reaction, water. However, these aspects have been studied only scarcely in the context of alcohol dehydration. Here, a series of mesoporous hybrid aluminosilicate catalysts containing CH3Si groups was prepared in one pot by non-hydrolytic sol-gel (NHSG). The presence of the methyl groups was verified by IR, solid-state NMR, and ToF-SIMS. Aluminum is mostly incorporated in tetrahedral coordination in the hybrid silica matrix. Two parameters were varied: (i) the Si:Al ratio and (ii) the Si:MeSi ratio. On the one hand, changing the Si:Al ratio had a marked impact on hydrophilicity, as attested by water sorption measurements. On the other hand, unexpectedly, the introduction of methyl groups had no clear influence on sample hydrophilicity. Nevertheless, some of the methylated aluminosilicate catalysts markedly outperformed the purely inorganic catalysts and a commercial silica-alumina benchmark. While a direct influence of surface hydrophilicity or hydrophobicity could be excluded, characterization of acidity (IR-pyridine) revealed that these improved performances are correlated with a modification of the acidic properties in the hybrid catalysts caused by the presence of methyl groups. A decisive role of acidity in ethanol dehydration was confirmed by an experiment with delayed addition of the Al precursor in the NHSG synthesis. This led to a higher Al surface concentration, marked acid sites number increase, and better catalytic performance, even competing with HZSM-5 in terms of activity. Aluminosilicate ; Catalysis ; Mesoporous material ; Dehydration ; Hydrolysis ; Chemistry ; Sorption ; Chemical engineering ; Pyridine ; Hybrid material ; Context (archaeology) ; Inorganic chemistry ; Materials science ; Organic chemistry ; Adsorption Mesoporous Materials and Catalysis ; Catalysis for Biomass Conversion ; Zeolite Catalysis and Synthesis
Authors: Anka Utama Putra | Deniz Çakmaz | Nurgül Seferoğlu | Alberto Barsella | Zeynel Seferoğlu
Source:  (preprint, 2020-03-23)
Field: Chemistry — Physical and Theoretical Chemistry

New styryl based organic chromophores including free amino and azomethine groups: Syntheses, photophysical, NLO and thermal properties In this manuscript, we have successfully synthesized and characterized a new series of styryl based push-pull dyes containing free amino group and their Schiff bases derivatives in which dicyanomethylene was used as the acceptor group and different para-substituted alkylamines as the donor groups and 2-pyridyl as proton sensitive group. All compounds showed absorption in the visible region and green-red emission with low quantum yields. The photophysical properties were examined in various solvents with different polarities. The absorption and emission maxima were shifted bathocromically by increasing solvents polarity however, there was no regular correlation with polarity parameter. Significant red shifts were observed in the absorption and fluorescence emission maxima on increasing the electron-donating ability of the substituents. The observed color changes were photographed naked eyes and under illuminating UV-lamp. The pH sensitive properties of newly prepared Schiff bases against TBAOH were examined inside DMSO, furthermore their reserve protonation were also investigated using TFA. The structural and electronic properties of all newly synthesized compounds were studied using DFT calculation. In addition, NLO property of compounds were investigated by DFT. For determination thermal properties of all compounds were investigated and they showed good thermal stability up to 250 o C by TGA analyses under inert atmosphere. Our results indicate that the styryl based new push-pull dyes are promising candidate materials for NLO and pH applications. Chromophore ; Protonation ; Absorption (acoustics) ; Chemistry ; Photochemistry ; Thermal stability ; Fluorescence ; Materials science ; Organic chemistry Photochemistry and Electron Transfer Studies ; Luminescence and Fluorescent Materials ; Photochromic and Fluorescence Chemistry
Authors: Jonathan D. Lynch
Source: ScholarsArchive  (Brigham Young University) (article, 2020-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

Breaking the Organic Mold: Introducing Copper into the Influenza A Arena with Neutral and Divalent Complexes Influenza A (IVA) continues to pose a growing global threat even as current medications are becoming less effective. One of the main avenues of research into new anti-IVA drugs is its homotetrameric Matrix 2 proton channel (M2A), without which the virus would be unable to release its viral RNA into the host cell. The drug amantadine used to bind and block M2A until near-ubiquitous resistance formed as an M2A-S31N mutation, starting around 1995 and proceeding to 2005 when amantadine was disallowed for use as an anti-IVA drug. The standard organic structure currently being used for M2A inhibitor research comprises an adamantyl foot group, a heterocyclic aryl body group, and a cyclic head group. A sample set of compounds with this standard structure was compared and reviewed, focusing on positive and negative moieties and modifications. Modifications on the foot group were all more or less detrimental, body groups with two heteroatoms were advantageous, and larger head groups appeared better. Four other scaffolds known to literature were proposed for further study due to beneficial aspects of each. Where most anti-M2A research deals exclusively with organic compounds, metals and their potential in drugs have been almost entirely ignored due to the increased toxicity they bring. Free copper was found in past research to be the only first-row transition metal to show significant M2A-inhibitory activity, proposed to do so by binding the H37 cluster that acts as a pH-dependent control switch for the channel. Six overall-neutral copper complexes were synthesized as a combination of amantadine, cyclooctylamine, and null scaffolds with two of either acetate or acetamide arms as chelators. The complexes were found to block both M2A-WT and M2A-S31N. Along with CuCl¬¬2, though, they had little to no effect on M2A-H37A, providing confirming evidence that the copper binds at the H37 tetrad. Only one complex, Cu(cyclooctylamineiminodiacetate), outperformed CuCl2 in channel block studies and efficacy against two IVA strains, but all of the complexes were found to have lower cytotoxicity. Because M2-H37 is highly conserved, these complexes show promise for further testing against all strains of influenza A. Five net-divalent copper complexes were then synthesized with multiple aza or amine groups as chelators. The complexes failed to show any significant activity against M2A, however, which was thought to be due to size or polarity rejection or electromagnetic repulsion. One of the ligands, though, an adamantyl derivative of a tetraaza macrocycle, was a novel compound, and its copper complex, along with two others, were unknown to the CCDC database. The three complexes were characterized by X-ray diffraction and discussed. Copper ; Divalent ; Chemistry ; Mold ; Materials science ; Organic chemistry ; Composite material Various Chemistry Research Topics ; Historical Medical Research and Treatments
Authors: Clara Jarauta-Córdoba | Maider Gómez | Javier Marcos González | J.L. Pinilla | Isabel Suelves Laiglesia | Carmen Bartolomé
Source: DIGITAL.CSIC (Spanish National Research Council (CSIC)) (article, 2020-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Agrobiomass-Derived Activated Carbons as Potential Materials for Supercapacitors: Wheat Straw and Corn Stalk Case Studies The main goal of AGROinLOG is the demonstration of Integrated Biomass Logistic Centres (IBLC) for food and non-food products, evaluating their technical, environmental and economic feasibility. The project is based on agro-industries, which are willing to deploy new business lines in their facilities, opening new markets in bio-commodities (energy, transport and manufacturing purposes) and intermediate bio-products (transport and biochemicals). More specifically, this work is focused on a fodder industry, whose main activity is related to the dehydration of wheat straw and corn stalk to produce animal bedding and feeding. The object of this study is the evaluation of two biomass-based materials (i.e. wheat straw and corn stalk) to determine the potential of these feedstock as raw materials for the synthesis of activated carbons (ACs) and their further application as supercapacitors. Stalk ; Straw ; Agronomy ; Supercapacitor ; Activated carbon ; Pulp and paper industry ; Chemistry ; Engineering ; Biology ; Horticulture ; Organic chemistry ; Capacitance Supercapacitor Materials and Fabrication ; Aerogels and thermal insulation ; Fiber-reinforced polymer composites
Authors: Jie Jian | Jordi Poater | Roel Hammink | Paul Tinnemans | Christine J. McKenzie | F. Matthias Bickelhaupt | Jasmin Mecinović
Source: ChemPhysChem (article, 2020-06-03)
Field: Chemistry — Organic Chemistry

Through‐Space Polar‐π Interactions in 2,6‐Diarylthiophenols Abstract The front cover artwork is provided by Marijn Maas from the group of Prof. Jasmin Mecinović (University of Southern Denmark). The image shows the stabilization of thiols by aromatic rings, as a result of energetically favorable SH‐π interactions in a designed small molecule and in proteins. Read the full text of the Article at 10.1002/cphc.202000132 . Polar ; Space (punctuation) ; Chemistry ; Chemical physics ; Materials science ; Computational chemistry ; Physics ; Computer science ; Quantum mechanics Organic Chemistry Cycloaddition Reactions ; Crystallography and molecular interactions ; Photochromic and Fluorescence Chemistry
Authors: Amélie Robitaille
Source: Corpus Université Laval (Université Laval) (article, 2020-01-01)
Field: Materials Science — Biomaterials

Développement de polymères tt-conjugués de type n (accepteurs) par poly (hétéro)arylation directe et fabrication de cellules solaires tout polymère Cette thèse porte principalement sur le développement de nouveaux polymères de type n à base de naphtalène diimide et de pérylène diimide obtenus par polymérisation par (hétéro)arylation directe (PHAD) pour la fabrication de cellules solaires tout polymère. Tout d’abord, les deux premiers chapitres portent sur le développement d’une méthode robuste de PHAD sur des polymères bien connus de la littérature, le PNDIOD-T2 et le PNDIBS deux analogues à base de naphtalène diimide. Les polymères synthétisés via cette méthode ont été comparés à des matériaux synthétisés par une méthode dite classique dans le domaine; la polymérisation croisée de Stille-Migita. Cela a permis d’étudier la structure des matériaux pour en évaluer la régiorégularité; une caractéristique clef dans l’électronique organique étant donné que quelques pourcents de défauts au sein des structures peuvent entraîner une diminution importante des performances. Dans le cadre de ces chapitres, il a été possible de développer une méthode permettant d’obtenir des matériaux plus régiorégulier que lors de l’utilisation de la méthode classique; chose très peu répandue dans la littérature, mais au combien important. En effet, la PHAD est une méthode plus simple, plus écoresponsable que sa comparse ce qui ouvrirait les portes pour la réduction des coûts à l’échelle industrielle en plus de permettre la création d’énergies vertes via de la chimie verte. À la suite du développement de cette méthode, un nouveau défi était donc de développer de nouveaux matériaux accepteurs d’électrons. Pour ce faire, nous avons choisi de synthétiser des matériaux de types accepteur-accepteur pour moduler les propriétés optoélectroniques. Cette technique visait à diminuer les niveaux énergétiques des matériaux afin d’être plus complémentaire à ceux des matériaux donneurs. De cette façon, il serait possible d’obtenir une absorption des photons du soleil sur une plus large gamme de longueur d’onde afin d’améliorer les performances des cellules solaires organiques. Malheureusement, malgré la réussite d’obtention de propriété optoélectroniques désirées, les polymères synthétisés ne présentent pas des caractéristiques photovoltaïques intéressantes, ce qui pourrait s’expliquer par une morphologie de la couche active inadéquate. Chemistry ; Physics ; Materials science biodegradable polymer synthesis and properties ; Modular Robots and Swarm Intelligence
Authors: Islam MS
Source: Research & Development in Material Science (article, 2020-11-20)
Field: Materials Science — Polymers and Plastics

Nonwoven Hemp Fibre Reinforced Acrodur Biocomposites and their Mechanical Performance in Immersed Water Acrodur, aqueous polyacrylic acid solution and dispersion, has been developed as an alternative wood adhesive to phenolic and urea formaldehyde resins. It has many environmental benefits over the conventional thermoset resins that include its non-corrosive nature and non-emission of carcinogenic gases. It has superior tolerance to moisture during composite fabrication and thus drying of the preforms may be minimised or even eliminated contrary to most resins used in natural fibre biocomposites. The aim of this study was to produce optimised hemp fibre reinforced Acrodur resin biocomposites using nonwoven hemp fibre mats by varying Acrodur solution to dispersion ratio, relative humidity, curing time and temperature. The optimised biocomposites gave the best combination of 26.4MPa-cm3/g specific tensile strength and 4.4GPa-cm3/g specific Young’s modulus with 0.94g/cm3density. Thermogravimetric analysis (TGA) and contact angle measurement showed similar thermal stability and increased hydrophobicity of the biocomposites than those of the fibres. From the water immersion test, the path of wicking of water moleculesinto the biocomposites was believed to be rather straight than tortuous and about 43.5% loss of tensile strength and 57.1% loss of Young’s modulus were observed upon 4-week water immersion of the biocomposites. Materials science ; Composite material ; Ultimate tensile strength ; Thermogravimetric analysis ; Curing (chemistry) ; Composite number ; Thermosetting polymer ; Relative humidity ; Natural fiber ; Chemical engineering Natural Fiber Reinforced Composites ; Textile materials and evaluations ; Additive Manufacturing and 3D Printing Technologies
Authors: Dickron R. Nahhas
Source: Scholarship@Western (Western University) (article, 2020-01-01)
Field: Chemistry — Inorganic Chemistry

N-Heterocyclic Carbene Ligated Group 11 Trimethylsilylchalcogenolates: Building Blocks for Heterometallic Chalcogenide Molecules The synthesis of heterometallic chalcogenide molecules requires the continued investigation into the appropriate reagents necessary to introduce metal – chalcogen bonds in a controlled fashion. Trimethylsilyl metallochalcogenolates (MESiMe3) act as synthons introducing “ME–“ in solution upon reacting with an appropriate ternary metal reagent, MX (X= halide, acetate, etc.). Recent work makes use of N–heterocyclic carbenes (NHCs) as a class of ancillary ligand that can stabilize these reagents and the heterometallic chalcogenide molecules obtained with them. Building on previous work, this thesis describes the synthesis of group 11 trimethylsilyl metallochalcogenolates stabilized by bis–1,3–tritylimidazole–2–ylidene (abbreviated ITr) to build this library of compounds and investigate their reactivity towards dinuclear chalcogenide molecules, [(ITr)2M(μ2–E)M’] (M=Cu, Ag, Au; E=S, Se). Surprisingly, the reaction of [ITrMESiMe3] with [ITrMOAc] did not yield the desired products in a selective manner. Attempts are made to rationalize the failure to obtain both the homo and heterometallic compounds by this general method and by other previously established techniques. Carbene ; Chalcogenide ; Group (periodic table) ; Chemistry ; Molecule ; Stereochemistry ; Catalysis ; Organic chemistry Synthesis and characterization of novel inorganic/organometallic compounds ; Organometallic Complex Synthesis and Catalysis ; Inorganic Chemistry and Materials
Authors: Kun Liu | Ariella Lukach | Héloïse Thérien‐Aubin | Kouta Sugikawa | Jemma Vickery | Siyon Chung | Michael Rubinstein | Bai Yang | Eugenia Kumacheva
Source: Carolina Digital Repository (University of North Carolina at Chapel Hill) (article, 2020-10-30)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Copolymerization of Metal Nanoparticles: A Route to Colloidal Plasmonic Copolymers The resemblance between colloidal and molecular polymerization reactions has been recognized as a powerful tool for the fundamental studies of polymerization reactions, as well as a platform for the development of new nanoscale systems with desired properties. Future applications of colloidal polymers will require nanoparticle (NP) ensembles with a high degree of complexity that can be realized by hetero-assembly of NPs with different dimensions, shapes and compositions. In the present work, we have developed a method to apply strategies from molecular copolymerization to the co-assembly of gold nanorods with different dimensions into random and block copolymer structures (plasmonic copolymers). The approach was extended to the co-assembly of random copolymers of gold and palladium nanorods. A kinetic model validated and further expanded the kinetic theories developed for molecular copolymerization reactions. Copolymer ; Colloid ; Nanoparticle ; Nanotechnology ; Materials science ; Plasmon ; Metal ; Chemical engineering ; Polymer science ; Polymer chemistry ; Polymer ; Optoelectronics ; Engineering ; Composite material ; Metallurgy Gold and Silver Nanoparticles Synthesis and Applications ; Nanomaterials for catalytic reactions
Authors: Raymond Kane
Source: Organic and Medicinal Chemistry International Journal (article, 2020-06-24)
Field: Materials Science — Materials Chemistry

Synthesis Condition and Treatment Assisted Tuning of Structural, Magnetic Properties and Bandgap of Ni Nano Ferrite Organic and Medicinal chemistry international Journal is an open access journal that is committed to publish the papers on various topics of chemistry, especially synthetic organic chemistry, and pharmacology and various other biological specialties Materials science ; Ferrite (magnet) ; Nano- ; Band gap ; Nanotechnology ; Composite material ; Optoelectronics Magnetic Properties and Synthesis of Ferrites
Authors: S N Kane
Source: Organic and Medicinal Chemistry International Journal (article, 2020-06-24)
Field: Materials Science — Materials Chemistry

Synthesis Condition and Treatment Assisted Tuning of Structural, Magnetic Properties and Bandgap of Ni Nano Ferrite Organic and Medicinal chemistry international Journal is an open access journal that is committed to publish the papers on various topics of chemistry, especially synthetic organic chemistry, and pharmacology and various other biological specialties Publication ; Ferrite (magnet) ; Nanotechnology ; Nano- ; Band gap ; Materials science ; Chemistry ; Optoelectronics ; Political science ; Composite material Magnetic Properties and Synthesis of Ferrites