jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Elena Lucenti | Alessandra Forni | Daniele Marinotto | Andrea Previtali | Stefania Righetto | Elena Cariati
Source: Inorganics (article, 2019-03-09)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Tuning the Linear and Nonlinear Optical Properties of Pyrene-Pyridine Chromophores by Protonation and Complexation to d10 Metal Centers § The linear and second-order nonlinear optical (NLO) properties of two pyrene-pyridine chromophores, namely, 4-(pyren-1-yl)pyridine (L1) and 4-(2-(pyren-1-yl)ethyl)pyridine (L2), were investigated and modulated by performing protonation/deprotonation cycles or by complexation to d10 metal centers such as Zn(II) and Cu(I) to form the monomeric [Zn(CH3CO2)2(L1)2] complex and the [CuI(L2)]n coordination polymer, respectively. The structures of L1, L2, [Zn(CH3CO2)2(L1)2] and [CuI(L2)]n were determined by means of single-crystal X-ray diffraction studies. The NLO response, measured by the electric-field-induced second harmonic generation (EFISH) technique, was positive for both chromophores and showed an inversion of the sign after exposure to HCl vapors. This process was completely reversible and the original values were restored by simple exposure to NH3 vapors. Coordination of L1 to Zn(II) also resulted in a negative NLO response, although smaller in magnitude compared to the protonated form, due to the weak Lewis acidity of the “Zn(CH3CO2)2” fragment. The results were also interpreted on the basis of DFT/TDDFT calculations. Chemistry ; Protonation ; Chromophore ; Pyridine ; Deprotonation ; Pyrene ; Time-dependent density functional theory ; Metal ; Zinc ; Photochemistry ; Crystallography ; Density functional theory ; Medicinal chemistry ; Computational chemistry ; Organic chemistry Nonlinear Optical Materials Research ; Molecular spectroscopy and chirality ; Photochemistry and Electron Transfer Studies
Authors: Francesco Muniz‐Miranda | Liesbeth De Bruecker | Arthur De Vos | Flore Vanden Bussche | Christian V. Stevens | Pascal Van Der Voort | Kurt Lejaeghere | Véronique Van Speybroeck
Source: The Journal of Physical Chemistry A (article, 2019-07-19)
Field: Materials Science — Materials Chemistry

Optical Properties of Isolated and Covalent Organic Framework-Embedded Ruthenium Complexes Heterogenization of RuL<sub>3</sub> complexes on a support with proper anchor points provides a route toward design of green catalysts. In this paper, Ru(II) polypyridyl complexes are investigated with the aim to unravel the influence on the photocatalytic properties of varying nitrogen content in the ligands and of embedding the complex in a triazine-based covalent organic framework. To provide fundamental insight into the electronic mechanisms underlying this behavior, a computational study is performed. Both the ground and excited state properties of isolated and anchored ruthenium complexes are theoretically investigated by means of density functional theory and time-dependent density functional theory. Varying the ligands among 2,2'-bipyridine, 2,2'-bipyrimidine, and 2,2'-bipyrazine allows us to tune to a certain extent the optical gaps and the metal to ligand charge transfer excitations. Heterogenization of the complex within a CTF support has a significant effect on the nature and energy of the electronic transitions. The allowed transitions are significantly red-shifted toward the near IR region and involve transitions from states localized on the CTF toward ligands attached to the ruthenium. The study shows how variations in ligands and anchoring on proper supports allows us to increase the range of wavelengths that may be exploited for photocatalysis. Ruthenium ; Covalent bond ; Chemistry ; Combinatorial chemistry ; Materials science ; Nanotechnology ; Polymer chemistry ; Organic chemistry ; Catalysis Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Advanced Photocatalysis Techniques
Authors: Yun‐Long Wu | Zibiao Li
Source: Therapeutic Delivery (article, 2019-05-29)
Field: Materials Science — Biomaterials

The Perspectives of Using Unimolecular Micelles in Nanodrug Formulation Together with the advantages of ease in functionalization, biodegradability and biocompatibility, unimolecular micelles could be interesting for drug delivery, bio-imaging and theranostic platform designs. Micelle ; Nanocarriers ; Bioavailability ; Chemistry ; Nanotechnology ; Druggability ; Solubility ; Aqueous solution ; Materials science ; Drug delivery ; Combinatorial chemistry ; Organic chemistry ; Pharmacology ; Medicine ; Biochemistry Nanoparticle-Based Drug Delivery ; Advanced Drug Delivery Systems ; Dendrimers and Hyperbranched Polymers
Authors: Muhammad Ahsan Iqbal | Humaira Asghar | Muhammad Adeel Iqbal | Michele Fedel
Source: SN Applied Sciences (article, 2019-06-04)
Field: Materials Science — Materials Chemistry

Sorption of As(V) from aqueous solution using in situ growth MgAl–NO3 layered double hydroxide thin film developed on AA6082 Sorption ; Aqueous solution ; In situ ; Hydroxide ; Materials science ; Chemical engineering ; Layered double hydroxides ; Chemistry ; Adsorption ; Organic chemistry ; Engineering Layered Double Hydroxides Synthesis and Applications ; Magnesium Oxide Properties and Applications ; Adsorption and biosorption for pollutant removal
Authors: Katarzyna N. Jarzembska | Michał Hapka | Radosław Kamiński | Wojciech Bury | Sylwia E. Kutniewska | Dariusz Szarejko | M. M. Szczȩśniak
Source: Crystals (article, 2019-01-12)
Field: Materials Science — Materials Chemistry

On the Nature of Luminescence Thermochromism of Multinuclear Copper(I) Benzoate Complexes in the Crystalline State A model luminescent [(PhCO2)4Cu4] (Cu4) complex in the crystalline state was investigated via combined crystallographic and spectroscopic techniques contributed substantially by theoretical modelling. The complex appeared to exhibit luminescence thermochromism, i.e., red phosphorescence at room temperature which changes to green when lowering the temperature to 90 K. The low-energy emissive state was assigned as a cluster-centred triplet, 3CC. The emission from this state predicted in TDDFT (~635 nm) matches the experimental red band observed at 660–715 nm. In contrast, the nature of the high-energy “green” band was less straightforward. The next reached cluster-centred triplet excited state occurred to be energetically close to the experimental value of ~545 nm. The two excited states also exhibit significant metal-to-ligand and ligand-to-metal charge transfer characteristics, especially for solid-state distorted geometries. In both cases the cluster core was expected to become notably contracted when compared to the ground state. Time-resolved photocrystallographic results supported the computationally predicted core contraction upon excitation. Additionally, the differences between the spectroscopic behaviour of the related tetra- and hexanuclear copper(I) complexes, Cu4 and Cu6 (i.e., [(PhCO2)6Cu6]) in the crystalline state were discussed and examined. It appeared that crystal packing may constitute an important factor as far as the lack of luminescence thermochromism in the latter case is concerned. Synopsis: Structure–property relationships characterising a model luminescent [(PhCO2)4Cu4] (Cu4) complex in the crystalline state were investigated via combined crystallographic and spectroscopic techniques contributed by theoretical modelling, and compared with the properties of the related [(PhCO2)6Cu6] (Cu6) complex. Thermochromism ; Luminescence ; Phosphorescence ; Excited state ; Crystallography ; Cluster (spacecraft) ; Triplet state ; Chemistry ; Time-dependent density functional theory ; Ground state ; Photochemistry ; Materials science ; Chemical physics ; Atomic physics ; Fluorescence ; Optics ; Optoelectronics ; Physics ; Organic chemistry Nanocluster Synthesis and Applications ; Metal complexes synthesis and properties ; Porphyrin and Phthalocyanine Chemistry
Authors: João B. Costa | Joana Silva‐Correia | Sandra Pina | Alain da Silva Morais | Sílvia Vieira | Hélder Pereira | João Espregueira‐Mendes | Rui L. Reis | Joaquím M. Oliveira
Source: Bio-Design and Manufacturing (article, 2019-08-21)
Field: Materials Science — Biomaterials

Indirect printing of hierarchical patient-specific scaffolds for meniscus tissue engineering Fibroin ; Materials science ; Meniscus ; Tissue engineering ; Genipin ; Scaffold ; Apatite ; Porosity ; Compressive strength ; Biomedical engineering ; Composite material ; Chemistry ; SILK ; Mineralogy Silk-based biomaterials and applications ; Knee injuries and reconstruction techniques ; Bone Tissue Engineering Materials
Authors: Mariano Curti | Cecilia B. Mendive | Thomas Bredow | M. Mangir Murshed | Thorsten M. Gesing
Source: Journal of Physics Condensed Matter (article, 2019-05-09)
Field: Materials Science — Materials Chemistry

Structural, vibrational and electronic properties of SnMBO<sub>4</sub> (M = Al, Ga): a predictive hybrid DFT study Abstract We propose two new members of the mullite-type family, SnAlBO 4 and SnGaBO 4 , and carry out an in-depth study of their crystal properties using the hybrid method PW1PW. Both are isostructural to PbMBO 4 (M = Fe, Mn, Al, Ga), which show axial negative linear compressibility (ANLC), among other interesting features. We find that, although Sn 2+ is susceptible of being oxidized by oxygen, a suitable range of experimental parameters exists in which the compounds could be synthesized. We observe absence of ANLC below 20 GPa and explain it by the small space occupied by the lone electron pairs, as indicated by the small length of the corresponding Liebau Density Vectors. In agreement with this fact, the structures present a low number of negative mode-Grüneisen parameters, which may also suggest lack of negative thermal expansion. The electronic properties show a remarkable anisotropic behaviour, with a strong dependence of the absorption spectra on light polarization direction. Isostructural ; Anisotropy ; Lone pair ; Materials science ; Tetragonal crystal system ; Negative thermal expansion ; Density functional theory ; Condensed matter physics ; Crystallography ; Molecular physics ; Thermal expansion ; Chemical physics ; Crystal structure ; Computational chemistry ; Chemistry ; Optics ; Physics ; Molecule Thermal Expansion and Ionic Conductivity ; Nuclear materials and radiation effects ; High-pressure geophysics and materials
Authors: Qiang Liu | Xiaoshan Wang | Jialiang Wang | Xiao Huang
Source: Acta Physico-Chimica Sinica (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Spatially Controlled Two-dimensional Heterostructures &lt;i&gt;via&lt;/i&gt; Solution-phase Growth Heterojunction ; Phase (matter) ; Materials science ; Optoelectronics ; Physics ; Quantum mechanics 2D Materials and Applications ; Photonic Crystals and Applications ; Perovskite Materials and Applications
Authors: Quentin Huaulmé | Cyril Aumaître | Outi Vilhelmiina Kontkanen | David Beljonne | Alexandra Sutter | Gilles Ulrich | Renaud Demadrille | Nicolas Leclerc
Source: Beilstein Journal of Organic Chemistry (article, 2019-07-24)
Field: Materials Science — Materials Chemistry

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells We report two novel functional dyes based on a boron-dipyrromethene (BODIPY) core displaying a panchromatic absorption with an extension to the near-infrared (NIR) range. An innovative synthetic approach for preparing the 2,3,5,6-tetramethyl-BODIPY unit is disclosed, and a versatile way to further functionalize this unit has been developed. The optoelectronic properties of the two dyes were computed by density functional theory modelling (DFT) and characterized through UV-vis spectroscopy and cyclic voltammetry (CV) measurements. Finally, we report preliminary results obtained using these functional dyes as photosensitizers in dye-sensitized solar cells (DSSCs). BODIPY ; Dye-sensitized solar cell ; Panchromatic film ; Chemistry ; Density functional theory ; Cyclic voltammetry ; Characterization (materials science) ; Photochemistry ; Absorption (acoustics) ; Functional group ; Absorption spectroscopy ; Fluorescence ; Nanotechnology ; Organic chemistry ; Materials science ; Electrochemistry ; Physical chemistry ; Computational chemistry ; Optics Luminescence and Fluorescent Materials ; Advanced Photocatalysis Techniques ; TiO2 Photocatalysis and Solar Cells
Authors: Georgios G. Vogiatzis | van Lca Lambèrt Breemen | Doros N. Theodorou | Markus Hütter
Source: Computer Physics Communications (article, 2019-11-04)
Field: Materials Science — Materials Chemistry

Free energy calculations by molecular simulations of deformed polymer glasses A rigorous thermodynamic framework is developed for performing free energy calculations of polymer glasses described by classical molecular forcefields. The proper free energy connected to all combinations of imposed external conditions (strain, stress) is derived from a well defined Helmholtz energy calculated from the detailed atomistic configurations. The quasi-harmonic approximation (QHA) is employed around local minima of the system on its potential energy landscape. The ingredients of the methodology, i.e. the derivatives of the free energy with respect to atomic positions (forces, elements of the Hessian) and the relevant derivatives with respect to strain (stresses and elastic constants), are calculated through tractable analytic expressions which are thoroughly presented and discussed. The derivation is general and readily applicable to any system described by classical molecular forcefields. As a proof of concept, we study the mechanical response of long-chain glassy atactic polystyrene, in the elastic and the plastic regime (compressive strain up to 100%). The macroscopic stress–strain curve for polystyrene is obtained and the evolution of the microscopic polymer configurations in the course of deformation is studied. Helmholtz free energy ; Hessian matrix ; Maxima and minima ; Polystyrene ; Polymer ; Stress (linguistics) ; Materials science ; Deformation (meteorology) ; Molecular dynamics ; Strain energy ; Anisotropy ; Statistical physics ; Thermodynamics ; Physics ; Mathematical analysis ; Mathematics ; Composite material ; Quantum mechanics Material Dynamics and Properties ; Polymer crystallization and properties ; Glass properties and applications
Authors: Xiangchao Zhu | Ahmet Çiçek | Yixiang Li | Ahmet Ali Yanik
Source: Scientific Reports (article, 2019-06-13)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Plasmofluidic Microlenses for Label-Free Optical Sorting of Exosomes Optical chromatography is a powerful optofluidic technique enabling label-free fractionation of microscopic bioparticles from heterogenous mixtures. However, sophisticated instrumentation requirements for precise alignment of optical scattering and fluidic drag forces is a fundamental shortcoming of this technique. Here, we introduce a subwavelength thick (<200 nm) Optofluidic PlasmonIC (OPtIC) microlens that effortlessly achieves objective-free focusing and self-alignment of opposing optical scattering and fluidic drag forces for selective separation of exosome size bioparticles. Our optofluidic microlens provides a self-collimating mechanism for particle trajectories with a spatial dispersion that is inherently minimized by the optical gradient and radial fluidic drag forces working together to align the particles along the optical axis. We demonstrate that this facile platform facilitates complete separation of small size bioparticles (i.e., exosomes) from a heterogenous mixture through negative depletion and provides a robust selective separation capability for same size nanoparticles based on their differences in chemical composition. Unlike existing optical chromatography techniques that require complicated instrumentation (lasers, objectives and precise alignment stages), our OPtIC microlenses with a foot-print of 4 μm × 4 μm open up the possibility of multiplexed and high-throughput sorting of nanoparticles on a chip using low-cost broadband light sources. Microvesicles ; Sorting ; Computer science ; Chemistry ; microRNA ; Biochemistry ; Algorithm Gold and Silver Nanoparticles Synthesis and Applications ; Plasmonic and Surface Plasmon Research ; Orbital Angular Momentum in Optics
Authors: Aaron H. Liepman | J. Vijayalakshmi | Daniel Peisach | Brian Hulsebus | Laura J. Olsen | Mark A. Saper
Source: Frontiers in Plant Science (article, 2019-10-11)
Field: Materials Science — Materials Chemistry

Crystal Structure Of Photorespiratory Alanine:Glyoxylate Aminotransferase 1 (AGT1) From Arabidopsis thaliana Photorespiration is an energetically costly metabolic pathway for the recycling of phosphoglycolate produced by the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO) to phosphoglycerate. <i>Arabidopsis</i> alanine:glyoxylate aminotransferase 1 (AGT1) is a peroxisomal aminotransferase with a central role in photorespiration. This enzyme catalyzes various aminotransferase reactions, including serine:glyoxylate, alanine:glyoxylate, and asparagine:glyoxylate transaminations. To better understand structural features that govern the specificity of this enzyme, its crystal structures in the native form (2.2-Å resolution) and in the presence of l-serine (2.1-Å resolution) were solved. The structures confirm that this enzyme is dimeric, in agreement with studies of the active enzyme in solution. In the crystal, another dimer related by noncrystallographic symmetry makes close interactions to form a tetramer mediated in part by an extra carboxyl-terminal helix conserved in plant homologs of AGT1. Pyridoxal 5'-phosphate (PLP) is bound at the active site but is not held in place by covalent interactions. Residues Tyr35' and Arg36', entering the active site from the other subunits in the dimer, mediate interactions between AGT and l-serine when used as a substrate. In comparison, AGT1 from humans and AGT1 from <i>Anabaena</i> lack these two residues and instead position a tyrosine ring into the binding site, which accounts for their preference for l-alanine instead of l-serine. The structure also rationalizes the phenotype of the <i>sat</i> mutant, Pro251 to Leu, which likely affects the dimer interface near the catalytic site. This structural model of AGT1 provides valuable new information about this protein that may enable improvements to the efficiency of photorespiration. Arabidopsis thaliana ; Glyoxylate cycle ; Alanine ; Alanine aminotransferase ; Biology ; Botany ; Chemistry ; Biochemistry ; Enzyme ; Amino acid ; Gene Enzyme Structure and Function ; Photosynthetic Processes and Mechanisms ; Polyamine Metabolism and Applications
Authors: Brian Chmielowiec | Tatsuki Fujimura | Tomohiro Otani | Kiego Aoyama | Toshiyuki Nohira | Takayuki Homma | Yasuhiro Fukunaka | Antoine Allanore
Source: Journal of The Electrochemical Society (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Experimental Measurement of Overpotential Sources during Anodic Gas Evolution in Aqueous and Molten Salt Systems Current interrupt and galvanostatic EIS techniques were utilized in a complementary fashion to characterize the different sources of overpotential during anodic gas evolution. Room temperature anodic evolution of oxygen at a nickel working electrode in aqueous potassium hydroxide and the high temperature (348C) anodic evolution of chlorine at a glassy carbon working electrode in molten (LiCl) 57.5 -(KCl) 13.3 -(CsCl) 29.2 where investigatd. Combining of the two techniques enables to separate the total measured overpotential into its ohmic, charge transfer, and mass transfer components. Potential decay curves indicated that natural convection (due to both bubble evolution and density driven flow) was a major driving force in reestablishing equilibrium conditions at the working electrode surface. During oxygen evolution, charge transfer resistance dominated the total overpotential at low current densities, but as the current density approached 100mA/cm 2 , mass transfer overpotentials and ohmic overpotential became non-negligible. The mass transfer overpotential during chlorine evolution was found to be half that found during oxygen evolution. Overpotential ; Oxygen evolution ; Anode ; Chemistry ; Mass transfer ; Analytical Chemistry (journal) ; Molten salt ; Electrode ; Inorganic chemistry ; Materials science ; Electrochemistry ; Physical chemistry ; Chromatography Advancements in Solid Oxide Fuel Cells ; Molten salt chemistry and electrochemical processes ; Advanced battery technologies research
Authors: S.G.J. van Meerten | Gerrit E. Janssen | Arno P. M. Kentgens
Source: Journal of Magnetic Resonance (article, 2019-11-25)
Field: Chemistry — Spectroscopy

Rapid-melt DNP for multidimensional and heteronuclear high-field NMR experiments Low sensitivity is the main limitation of NMR for efficient chemical analysis of mass-limited samples. Hyperpolarization techniques such as Dynamic Nuclear Polarization (DNP) have greatly improved the efficiency of NMR experiments. In this manuscript, we demonstrate a 400 MHz rapid-melt DNP setup. With this setup it is possible to perform liquid-state NMR experiments with solid-state DNP enhancement at high magnetic field. Sample volumes of 100 nL in fused-silica capillaries are detected using a stripline microcoil. Due to the small heat capacity of these samples it is possible to melt them with relatively low relaxation losses. With this 400 MHz setup, proton enhancements of up to -175 have been obtained in the liquid-state. The probe is double tuned, so it can be used for heteronuclear DNP-NMR and since the sample composition does not change during the experiment, it is possible to perform signal averaging and multidimensional experiments. This type of rapid-melt DNP setup thus allows for most types of liquid-state NMR experiments to be combined with efficient solid-state DNP. This makes rapid-melt DNP an interesting method for high-throughput chemical analysis of mass-limited samples. Heteronuclear molecule ; Hyperpolarization (physics) ; Analytical Chemistry (journal) ; Chemistry ; Solid-state nuclear magnetic resonance ; Spins ; Nuclear magnetic resonance ; Microcoil ; Nuclear magnetic resonance spectroscopy ; Materials science ; Chromatography ; Electromagnetic coil ; Physics Advanced NMR Techniques and Applications ; Solid-state spectroscopy and crystallography ; NMR spectroscopy and applications
Authors: Shubo Wang | Bo Hou | Che Ting Chan
Source: Scientific Reports (article, 2019-10-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Broadband Microwave Absorption by Logarithmic Spiral Metasurface Metamaterials have enabled the design of electromagnetic wave absorbers with unprecedented performance. Conventional metamaterial absorbers usually employ multiple structure components in one unit cell to achieve broadband absorption. Here, a simple metasurface microwave absorber is proposed that has one metal-backed logarithmic spiral resonator as the unit cell. It can absorb >95% of normally incident microwave energy within the frequency range of 6 GHz-37 GHz as a result of the scale invariant geometry and the Fabry-Perot-type resonances of the resonator. The thickness of the metasurface is 5 mm and approaches the Rozanov limit of an optimal absorber. The physics underlying the broadband absorption is discussed. A comparison with Archimedean spiral metasurface is conducted to uncover the crucial role of scale invariance. The study opens a new direction of electromagnetic wave absorption by employing the scale invariance of Maxwell equations and may also be applied to the absorption of other classical waves such as sound. Metamaterial ; Microwave ; Broadband ; Electromagnetic radiation ; Logarithmic spiral ; Resonator ; Absorption (acoustics) ; Logarithm ; Spiral (railway) Metamaterials and Metasurfaces Applications ; Acoustic Wave Phenomena Research ; Electromagnetic wave absorption materials