jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: A. Sivakumar | Ana Rita | S. Sahaya Jude Dhas | S. A. Martin Britto Dhas | S.A. Martin Britto Dhas
Source: Optics & Laser Technology (article, 2020-03-31)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Tuning of surface plasmon resonance of silver nano particles by shock waves for plasmonic device applications Materials science ; Surface plasmon resonance ; Scanning electron microscope ; Shock wave ; Plasmon ; Diffraction ; Spectroscopy ; Optics ; Shock (circulatory) ; Nanoparticle ; Silver nanoparticle ; Surface plasmon ; Optoelectronics ; Nanotechnology ; Composite material Gold and Silver Nanoparticles Synthesis and Applications ; Laser-Ablation Synthesis of Nanoparticles ; Nonlinear Optical Materials Studies
Authors: Joseph Cadden | Krishna M. Gupta | Parijat Kanaujia | Simon J. Coles | Srinivasulu Aitipamula
Source: Crystal Growth & Design (article, 2020-12-22)
Field: Chemistry — Physical and Theoretical Chemistry

Cocrystal Formulations: Evaluation of the Impact of Excipients on Dissolution by Molecular Simulation and Experimental Approaches Cocrystallization has matured into an established technique for fine-tuning the physicochemical properties of active pharmaceutical ingredients (APIs). This technique has been adopted by pharmaceutical drug companies, with increasing numbers of cocrystal-based drug products now entering the market. Surprisingly, however, studies into the formulation aspects of cocrystal-based drugs are relatively few and far between compared to the vast literature on their design, synthesis, and characterization. We herein report the results of our investigations into cocrystal–excipient interactions in water that determine the dissolution properties of cocrystals in formulation by a combination of molecular dynamics (MD) simulation and experimental approaches. Two cocrystals of an antirheumatic drug, leflunomide (LEF) with 3-hydroxybenzoic acid (HBA) and 2-picolinic acid (PIC), were assessed in formulation with the frequently used excipients lactose and dibasic calcium phosphate (DCP). For comparison, the dissolution of neat LEF formulations with these excipients was also evaluated. The parameters deduced from MD simulations, such as solvent-accessible surface area, intermolecular hydrogen bonds among formulation ingredients and water, and interaction energy between the API (or cocrystal) and water were found to be essential indicators in the prediction of cocrystal formulation dissolution trends. It was found that the presence of lactose as an excipient improved the dissolution of the cocrystal formulation compared to the neat cocrystals, most notably for the LEF-PIC cocrystal. In contrast, DCP was seen to have a detrimental effect on the dissolution of cocrystal formulations, all exhibiting lower dissolution than their neat cocrystal counterparts and LEF. Careful analysis of these results revealed that the nature of the excipient plays a significant role in the dissolution properties. While the improved dissolution of the lactose formulations was attributed to its hydrophilic nature, the ionic and hydrophobic nature of DCP was likely responsible for its detrimental effect. The results of the MD simulations were found to be in excellent agreement with the experimentally observed dissolution hierarchy. Cocrystal ; Dissolution ; Chemistry ; Excipient ; Hydrogen bond ; Dissolution testing ; Dibasic acid ; Lactose ; Organic chemistry ; Combinatorial chemistry ; Chromatography ; Molecule ; Biopharmaceutics Classification System Crystallography and molecular interactions ; Crystallization and Solubility Studies ; Enzyme Structure and Function
Authors: Ajit Vikram | Arwa Zahid | Saket Bhargava | Logan P. Keating | Andre Sutrisno | Ankur Khare | Peter Trefonas | Moonsub Shim | Paul J. A. Kenis
Source: Chemistry of Materials (article, 2020-04-02)
Field: Materials Science — Materials Chemistry

Mechanistic Insights into Size-Focused Growth of Indium Phosphide Nanocrystals in the Presence of Trace Water Indium phosphide (InP) nanocrystals have emerged as a viable alternative to heavy metal-based colloidal quantum dots for optoelectronic applications. Traditionally, the presence of trace amounts of water during the synthesis of colloidal quantum dots is considered an undesired impurity because it prevents or slows down colloidal growth and alters the surface properties. Here, we report that fine-tuning the amount of trace water is the key for achieving size-focused growth of monodisperse InP nanocrystals synthesized using aminophosphine precursors. Using solid-state and solution nuclear magnetic resonance, we investigated the role of trace amounts of water in surface oxidation and precursor conversion reactions. Molecular insights from UV–vis spectroscopy and NMR revealed a profound contrast between the growth rates of the nanocrystals upon the addition of water to the reaction system. We demonstrate that by addition of a specific amount of water, the reactivity of the phosphorous precursor can be tuned to enable a constant supply of monomer throughout the reaction. Under an optimal precursor conversion rate, a size-focused growth behavior that is rare for InP nanocrystals is observed, suggesting the presence of an artificial LaMer-like growth regime. Nanocrystal ; Indium phosphide ; Materials science ; Colloid ; Indium ; Phosphide ; Quantum dot ; Nanotechnology ; Dispersity ; Chemical engineering ; Nanoparticle ; Metal ; Optoelectronics ; Polymer chemistry ; Metallurgy Quantum Dots Synthesis And Properties ; Chalcogenide Semiconductor Thin Films ; Copper-based nanomaterials and applications
Authors: Shasha Meng | Ze-Rong Tao | Wen‐Qi Tang | Ting Han | Yan Du | Zhi‐Yuan Gu
Source: Journal of Chromatography A (article, 2020-10-10)
Field: Chemistry — Inorganic Chemistry

Ultramicroporous metal-organic frameworks for capillary gas chromatographic separation Chemistry ; Chromatography ; Capillary action ; Chromatographic separation ; Metal-organic framework ; Capillary electrochromatography ; Gas chromatography ; Capillary gas chromatography ; Adsorption ; Capillary electrophoresis ; Organic chemistry ; High-performance liquid chromatography Metal-Organic Frameworks: Synthesis and Applications ; Molecular Sensors and Ion Detection ; Catalytic Processes in Materials Science
Authors: Meng Chen | Yingxin Wang | Wenle Ma | Yi Huang | Ziran Zhao
Source: ACS Applied Materials & Interfaces (article, 2020-05-26)
Field: Materials Science — Materials Chemistry

Ionic Liquid Gating Enhanced Photothermoelectric Conversion in Three-Dimensional Microporous Graphene The photothermoelectric (PTE) effect can effectively convert light into electricity through photothermal and thermoelectric processes and has great potential applications in light energy harvesting and bandgap-independent photodetection. It is particularly applicable for the terahertz (THz) range featuring low photon energy but has not been well established due to lack of high-performance PTE materials in this range. Three-dimensional microporous graphene (3DMG) foam possesses ultrahigh THz absorptivity and outstanding photothermal conversion and can serve as a promising candidate. Here, enhancement of the THz PTE response of 3DMG foam by fine-tuning its thermoelectric properties using the ionic liquid electric double layer (EDL) technique was demonstrated. Continuous and reversible control of the Seebeck coefficient of 3DMG highlights the effectiveness of EDL gating in manipulating the electronic structures of such bulk and porous material. An approximate 1 order of magnitude enhancement in the Seebeck coefficient as well as the PTE responsivity was observed. In addition, a double-cell 3DMG EDL device with a p-n junction like channel configuration enabled further improvement of the photoresponse. This work opens a new avenue to optimize the PTE performance of 2D nanosheet-assembled 3D porous materials for highly efficient energy harvesting and detection of THz radiation. Materials science ; Graphene ; Microporous material ; Ionic liquid ; Gating ; Ionic bonding ; Nanotechnology ; Chemical engineering ; Ion ; Organic chemistry ; Composite material ; Biophysics ; Catalysis Advanced Thermoelectric Materials and Devices ; Advanced Sensor and Energy Harvesting Materials ; Transition Metal Oxide Nanomaterials
Authors: Sanjib Panda | Arijit Singha Hazari | Manish Gogia | Goutam Kumar Lahiri
Source: Inorganic Chemistry (article, 2020-01-07)
Field: Chemistry — Inorganic Chemistry

Diverse Functionalization of Ruthenium-Chelated 2-Picolylamines: Oxygenation, Dehydrogenation, Cyclization, and <i>N</i>-Dealkylation "Chemical noninnocence" of metal-coordinated 2-picolylamine (PA) derivatives has been introduced upon its reaction with the metal precursor [Ru<sup>II</sup>(Cl)(H)(CO)(PPh<sub>3</sub>)<sub>3</sub>] under basic conditions. This in effect leads to the facile formation of metalated amide, imine, ring-cyclized pyrrole, and an N-dealkylated congener based on the fine-tuning of an amine nitrogen (N<sub>amine</sub>) and a methylene center (C<sub>α</sub>) at the PA backbone. It develops oxygenated L1' in <b>1</b> and cyclized L4' in <b>4</b> upon switching of the N<sub>amine</sub> substituent of PA from aryl to an electrophilic pent-3-en-2-one moiety. On the other hand, imposing the substituent at the C<sub>α</sub> position of PA modifies its reactivity profile, leading to a dehydrogenation (<b>2</b>/<b>3</b>) or <i>N</i>-dealkylation (<b>6</b>) process. The divergent reactivity profile of metalated PA is considered to proceed through a common dianionic intermediate. Further, a competitive scenario of C-H bond functionalization of coordinated PA versus the ligand-exchange process has been exemplified in the presence of external electrophile such as benzyl bromide or methylene iodide. Authentication of the product formation as well as elucidation of the reaction pathway has been addressed by their crystal structures and spectroscopic features in conjunction with the transition-state (TS) theory. Chemistry ; Substituent ; Electrophile ; Imine ; Reactivity (psychology) ; Alkylation ; Medicinal chemistry ; Amide ; Methylene ; Ruthenium ; Iodide ; Ligand (biochemistry) ; Regioselectivity ; Stereochemistry ; Organic chemistry ; Catalysis Metal-Catalyzed Oxygenation Mechanisms ; Catalytic C–H Functionalization Methods ; Asymmetric Hydrogenation and Catalysis
Authors: Domenico Pirone | Nuno A. G. Bandeira | Bartosz Tylkowski | Emily Boswell | Regine Labeque | Ricard Garcia‐Valls | Marta Giamberini
Source: Polymers (article, 2020-04-30)
Field: Materials Science — Materials Chemistry

Contrasting Photo-Switching Rates in Azobenzene Derivatives: How the Nature of the Substituent Plays a Role A molecular design approach was used to create asymmetrical visible light-triggered azo-derivatives that can be good candidates for polymer functionalization. The specific electron-donor substituted molecules were characterized and studied by means of NMR analyses and UV-visible spectroscopy, comparing the results with Time Dependent Density Functional (TD-DFT) calculations. A slow rate of isomerization (k<sub>i</sub> = 1.5 × 10<sup>-4</sup> s<sup>-1</sup>) was discovered for 4-((2-hydroxy-5methylphenyl) diazenyl)-3-methoxybenzoic acid (AZO1). By methylating this moiety, it was possible to unlock the isomerization mechanism for the second molecule, methyl 3-methoxy-4-((2-methoxy-5-methylphenyl) diazenyl)benzoate (AZO2), reaching promising isomerization rates with visible light irradiation in different solvents. It was discovered that this rate was heightened by one order of magnitude (k<sub>i</sub> = 3.1 × 10<sup>-3</sup> s<sup>-1</sup>) for AZO2. A computational analysis using density functional (DFT/PBE0) and wavefunction (QD-NEVPT2) methodologies provided insight into the photodynamics of these systems. Both molecules require excitation to the second (S<sub>2</sub>) excited state situated in the visible region to initiate the isomerization. Two classic mechanisms were considered, namely rotation and inversion, with the former being energetically more favorable. These azo-derivatives show potential that paves the way for future applications as building blocks of functional polymers. Likewise, they could be really effective for the modification of existing commercial polymers, thus transferring their stimuli responsive properties to polymeric bulky structures, converting them into smart materials. Azobenzene ; Substituent ; Chemistry ; Photochemistry ; Materials science ; Molecule ; Stereochemistry ; Organic chemistry Photochromic and Fluorescence Chemistry ; Photochemistry and Electron Transfer Studies ; Photoreceptor and optogenetics research
Authors: Ji Li | Yitian Du | Haitao Su | Shixuan Cheng | Yanxia Zhou | Yiguang Jin | Xian Qi
Source: Acta Pharmaceutica Sinica B (article, 2020-01-20)
Field: Chemistry — Organic Chemistry

Interfacial properties and micellization of triblock poly(ethylene glycol)-poly(ε-caprolactone)-polyethyleneimine copolymers This study aimed to explore the link between block copolymers' interfacial properties and nanoscale carrier formation and found out the influence of length ratio on these characters to optimize drug delivery system. A library of diblock copolymers of PEG-PCL and triblock copolymers with additional PEI (PEG-PCL-PEI) were synthesized. Subsequently, a systematic isothermal investigation was performed to explore molecular arrangements of copolymers at air/water interface. Then, structural properties and drug encapsulation in self-assembly were investigated with DLS, SLS and TEM. We found the additional hydrogen bond in the PEG-PCL-PEI contributes to film stability upon the hydrophobic interaction compared with PEG-PCL. PEG-PCL-PEI assemble into smaller micelle-like (such as PEG-PCL4006-PEI) or particle-like structure (such as PEG-PCL8636-PEI) determined by their hydrophilic and hydrophobic block ratio. The distinct structural architectures of copolymer are consistent between interface and self-assembly. Despite the disparity of constituent ratio, we discovered the arrangement of both chains guarantees balanced hydrophilic-hydrophobic ratio in self-assembly to form stable construction. Meanwhile, the structural differences were found to have significant influence on model drugs incorporation including docetaxel and siRNA. Taken together, these findings indicate the correlation between molecular arrangement and self-assembly and inspire us to tune block compositions to achieve desired nanostructure and drug loading. Copolymer ; Ethylene glycol ; PEG ratio ; Micelle ; Materials science ; Self-assembly ; Polymer chemistry ; Chemical engineering ; Hydrophobic effect ; Chemistry ; Polymer ; Nanotechnology ; Organic chemistry ; Aqueous solution ; Composite material Advanced Polymer Synthesis and Characterization ; Block Copolymer Self-Assembly ; Nanoparticle-Based Drug Delivery
Authors: Lujuan Xu | Seah Ling Kuan | Tanja Weil
Source: Angewandte Chemie (article, 2020-12-01)
Field: Chemistry — Organic Chemistry

Contemporary Approaches for Site‐Selective Dual Functionalization of Proteins Abstract Site‐selective protein functionalization serves as an invaluable tool for investigating protein structures and functions in complicated cellular environments and accomplishing semi‐synthetic protein conjugates such as traceable therapeutics with improved features. Dual functionalization of proteins allows the incorporation of two different types of functionalities at distinct location(s), which greatly expands the features of native proteins. The attachment and crosstalk of a fluorescence donor and an acceptor dye provides fundamental insights into the folding and structural changes of proteins upon ligand binding in their native cellular environments. Moreover, the combination of drug molecules with different modes of action, imaging agents or stabilizing polymers provides new avenues to design precision protein therapeutics in a reproducible and well‐characterizable fashion. This review aims to give a timely overview of the recent advancements and a future perspective of this relatively new research area. First, the chemical toolbox for dual functionalization of proteins is discussed and compared. The strengths and limitations of each strategy are summarized in order to enable readers to select the most appropriate method for their envisaged applications. Thereafter, representative applications of these dual‐modified protein bioconjugates benefiting from the synergistic/additive properties of the two synthetic moieties are highlighted. Surface modification ; Posttranslational modification ; Nanotechnology ; Combinatorial chemistry ; Chemistry ; Folding (DSP implementation) ; Dual (grammatical number) ; Computer science ; Computational biology ; Materials science ; Biochemistry ; Biology ; Engineering Click Chemistry and Applications ; Chemical Synthesis and Analysis ; Monoclonal and Polyclonal Antibodies Research
Authors: Alexander C. Forse | Kristen A. Colwell | Miguel I. Gonzalez | Stefan Benders | Rodolfo M. Torres-Gavosto | Bernhard Blümich | Jeffrey A. Reimer | Jeffrey R. Long
Source: ChemRxiv (preprint, 2020-03-25)
Field: Chemistry — Inorganic Chemistry

Influence of Pore Size on Carbon Dioxide Diffusion in Two Isoreticular Metal–Organic Frameworks The rapid diffusion of molecules in porous materials is critical for numerous applications including separations, energy storage, sensing, and catalysis. A common strategy for tuning guest diffusion rates is to vary the material pore size, although detailed studies that isolate the effect of changing this particular variable are lacking. Here, we begin to address this challenge by measuring the diffusion of carbon dioxide in two isoreticular metal–organic frameworks featuring channels with different diameters, Zn2(dobdc) (dobdc4– = 2,5-dioxidobenzene-1,4-dicarboxylate) and Zn2(dobpdc) (dobpdc4− = 4,4′-dioxidobiphenyl-3,3′-dicarboxylate), using pulsed field gradient NMR spectroscopy. An increase in the pore diameter from 15 Å in Zn2(dobdc) to 22 Å in Zn2(dobpdc) is accompanied by an increase in the self-diffusion of CO2 by a factor of 4 to 6, depending on the gas pressure. Analysis of the diffusion anisotropy in Zn2(dobdc) reveals that the self-diffusion coefficient for motion of CO2 along the framework channels is at least 10,000 times greater than for motion between the framework channels. Our findings should aid the design of improved porous materials for a range of applications where diffusion plays a critical role in determining performance. Pulsed field gradient ; Diffusion ; Porosity ; Metal-organic framework ; Carbon dioxide ; Anisotropy ; Chemistry ; Chemical physics ; Chemical engineering ; Porous medium ; Analytical Chemistry (journal) ; Self-diffusion ; Gaseous diffusion ; Molecule ; Nanotechnology ; Materials science ; Thermodynamics ; Physical chemistry ; Organic chemistry ; Optics Metal-Organic Frameworks: Synthesis and Applications ; Lanthanide and Transition Metal Complexes ; Hydrocarbon exploration and reservoir analysis
Authors: Nour Mani | Aaqil Rifai | Shadi Houshyar | Marsilea A. Booth | Kate Fox
Source: Medical Devices & Sensors (article, 2020-09-26)
Field: Materials Science — Materials Chemistry

Diamond in medical devices and sensors: An overview of diamond surfaces Abstract Significant challenges arise when the human body is damaged, diseased and unable to repair itself. Current biomaterials for biomedical devices have limitations to restore function, while materials for implants and sensors often invoke a large foreign body response. Therefore, there is a need to develop suitable biomaterials in the fields of medical devices and sensors. Diamond is emerging due to its many favourable properties including biocompatibility, antimicrobial capability, antifouling properties, electrical conductivity and chemical functionalization capability. Thin film coatings of diamond can be fabricated by chemical vapour deposition, or by particle coatings with nanodiamond materials. Hybrid/composite diamond materials include soft materials such as those processed by electrospinning and melt extrusion, as well as hard materials such as those processed by additive manufacturing. Additive manufacturing is a developing area for diamond biomaterial fabrication and can include both hard and soft materials. The fabrication method used will depend on the properties required of the biomaterial, as well as the application. In this mini‐review, recent progress on using diamond in medical devices and sensors is outlined, with particular emphasis on fabrication methods. We highlight selected applications from recent literature and, in closing, make comments and suggestions to advance the field and direction of diamond application in medical devices and sensors. Diamond ; Nanotechnology ; Materials science ; Fabrication ; Chemical vapor deposition ; Nanodiamond ; Biocompatibility ; Biomaterial ; Composite material Diamond and Carbon-based Materials Research ; Metal and Thin Film Mechanics ; Lubricants and Their Additives
Authors: Federico Di Sacco | Markus Gahleitner | Jingbo Wang | Giuseppe Portale
Source: Polymers (article, 2020-07-23)
Field: Materials Science — Polymers and Plastics

Systematic Investigation on the Structure-Property Relationship in Isotactic Polypropylene Films Processed via Cast Film Extrusion The effect of cast film extrusion processing conditions, such as the chill-roll temperature, temperature of the melt, and line speed, on the structure of different isotactic polypropylene homo- and random copolymers has been investigated by means of Small- and Wide-Angle X-ray Scattering (SAXS and WAXS) and correlated to stiffness and haze. Stiffness and transparency have been found to be strongly dependent on the temperature of the chill-roll. Interestingly, line speed has been found to affect the total crystallinity when the chill-roll temperature is increased, while an overall minor effect of the melt temperature was found for all cast films. The polymer characteristics, defined by the catalyst nature and comonomer content, affect the final material performance, with the single-site catalyzed grades performing better in both mechanics and optics. Haze levels were found to correlate with the mesophase content rather than to α-crystallinity and to be dependent on the domain size for all grades. The remarkably low haze levels reached by the single-site grade with higher isotacticity can arise from high nucleation rate and orientational effects, which ultimately yield smaller and smoother scattering domains. Materials science ; Crystallinity ; Tacticity ; Small-angle X-ray scattering ; Composite material ; Extrusion ; Comonomer ; Polypropylene ; Polymer ; Scattering ; Nucleation ; Rheology ; Copolymer ; Optics ; Polymerization ; Organic chemistry ; Chemistry Polymer crystallization and properties ; Polymer Nanocomposites and Properties ; biodegradable polymer synthesis and properties
Authors: Niklas R. Bennedsen | Søren Kramer | Søren Kegnæs
Source: Catalysis Science & Technology (article, 2020-01-01)
Field: Chemistry — Inorganic Chemistry

A chiral porous organic polymer as a heterogeneous ligand for enantioselective Pd-catalyzed C(sp<sup>3</sup>)–H functionalization Catalytic enantioselective C(sp<sup>3</sup>)–H functionalization remains a difficult task, even more so using heterogeneous catalysts. Enantioselective synthesis ; Surface modification ; Catalysis ; Ligand (biochemistry) ; Polymer ; Chemistry ; Combinatorial chemistry ; Polymer chemistry ; Organic polymer ; Organic chemistry ; Physical chemistry ; Receptor Metal-Organic Frameworks: Synthesis and Applications ; Catalytic C–H Functionalization Methods ; Covalent Organic Framework Applications