jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Monu Joy | Mario Wriedt
Source: Acta Crystallographica Section A Foundations and Advances (article, 2021-07-30)
Field: Chemistry — Inorganic Chemistry

Electronic structure–property relations of photochromic MOFs from the Cambridge Crystallographic Structural Database The photochromic characteristics, the reversible color change upon UV irradiation is common in pyridinium-based MOFs, and it has tremendous applications in various fields such as stimuli-responsive adsorption, modulation of emission colors, controlled reversible singlet oxygen generation, and inkless and erasable printing media, etc. Albeit the structural features responsible for the photochromic behavior in the viologens-based MOFs is well documented in the literature, the underlying mechanism for the donor-acceptor charge transfer is not yet established concerning the geometrical parameters. Understanding the electronic structure-based charge-transfer mechanism would enable the fine tuning of the photochromic applications. To execute the computation, a photochromic MOF database was created from the MOF-subset of CCDC, and time-depended density functional theory (TD-DFT) was used to comprehend these charge transfer mechanism through analyzing the appropriate excited state frontier molecular/crystal orbitals (FM/CO), and it account for the structure-property relationships. Photochromism ; Crystallography ; Property (philosophy) ; Materials science ; Chemistry ; Nanotechnology ; Philosophy Metal-Organic Frameworks: Synthesis and Applications ; Pigment Synthesis and Properties ; X-ray Diffraction in Crystallography
Authors: Carlos Lodeiro | Silvia Nuti | Carlos Fernández‐Lodeiro | Javier Fernández‐Lodeiro | Adrián Fernández‐Lodeiro | Jorge Pérez‐Juste | Isabel Pastoriza Santos | Alec P. LaGrow | Olivier Schraidt | José Luís Capelo
Source:  (preprint, 2021-08-23)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Polyallylamine assisted synthesis of 3D branched AuNPs with plasmon tunability in the vis-NIR region modification. This paper describes the synthesis of highly branched gold nanoparticles through a facile seeded growth approach using poly(allylamine hydrochloride) (PAH) as shape inducing agent. The obtained branched Au NPs present highly tunable optical properties in the Vis-NIR region from ca. 560 nm to 1260 nm. We controlled the morphology, and therefore the optical response, of the NPs by either changing the gold salt to seed ratio or fine-tuning the solution pH. We proposed that the formation of size-dependent PAH-AuCl4- aggregates as demonstrated by dynamic light scattering measurements, together with pH-dependent gold salt speciation, might be responsible for the branched morphology. Advanced electron microscopy techniques demonstrated the polycrystalline nature of the NPs and facilitated a better understanding of branched morphology. Additionally, the refractive index sensitivity estimated by the inflexion point of the Localized Surface Plasmon Resonance (LSPR) band can be controlled by tuning the nanoparticle branching. Furthermore, the versatility of the PAH chemistry allowed the easy functionalization of the synthesized NPs. Surface plasmon resonance ; Surface modification ; Colloidal gold ; Materials science ; Nanoparticle ; Branching (polymer chemistry) ; Dynamic light scattering ; Nanotechnology ; Plasmon ; Chemical engineering ; Morphology (biology) ; Allylamine ; Optoelectronics ; Polyelectrolyte ; Polymer Gold and Silver Nanoparticles Synthesis and Applications ; Graphene and Nanomaterials Applications ; Laser-Ablation Synthesis of Nanoparticles
Authors: D. Das | Jhimli Sarkar Manna | T. K. Bhattaycharya
Source: Research Square (preprint, 2021-06-02)
Field: Materials Science — Materials Chemistry

Phase Transition and Anisotropic Transport of MoS 2 /Chlorophyll Van der waal Heterostructure Formed via Biomimetic Photo-electron Donation Abstract In atomically-thin two-dimensional Vander-Waal-heterostructure [VDWHs], phase transition due to biomimetic photoelectron donationwith molecular ad-layer has never been explored. In this pursuit, systematic quantification of biomimetic-optical-creation of stable easy-solution-processed 1T MoS 2 chlorophyll (CHL-a) VDWHs has been examined. The 1T phase transformation dynamics and stabilization phenomenon have been quantified by optical anisotropy and Time-correlated-single-photon-counting. The material shows Luttinger transport phenomenon in the two-port device and supports MoS 2 interfaces can be fine-tuned with the molecular ad-layer as a result of strong anisotropic finite range correlation. This is validated by Density-Function-Theory. The negative differential resistance in Luttinger transport arises from conformational heterogeneity of CHL-a related to the scaling of Van der waal distances, which regulates coupling strength with temperature as supported by Molecular-Dynamics simulation. The photo-induced evolution of novel “anisotropic heterojunction” can stimulate a plethora of function-designable 2D VDWHs creation. Heterojunction ; Materials science ; Anisotropy ; Density functional theory ; Condensed matter physics ; Phase (matter) ; Phase transition ; Optoelectronics ; Chemical physics ; Nanotechnology ; Physics ; Chemistry ; Optics ; Computational chemistry 2D Materials and Applications ; Molecular Junctions and Nanostructures ; ZnO doping and properties
Authors: Joseph M. Parr | Clarissa Olivar | Thomas Saal | Ralf Haiges | Michael S. Inkpen
Source: ChemRxiv (preprint, 2021-10-31)
Field: Chemistry — Inorganic Chemistry

An improved route to osmium(IV) tetraaryl complexes Investigations into the reactivity, properties, and applications of osmium(IV) tetraaryl complexes have been hampered by their low yielding syntheses from volatile and toxic OsO4 (typically ≤34%). Here we show that air-stable M(aryl)4 compounds (M = Os, Ru; aryl = 2-tolyl, 2,5-xylyl) can be prepared in improved yields (≤73%) starting from new, less hazardous (Oct4N)2[MX6] precursors (M = Os, Ru; X = Cl, Br). This approach also facilitates the preparation of Os(mesityl)4 (Os3), a complex comprising bulky 2,6-methyl substituted aryl ligands, for the first time (5% yield). We evaluate the X-ray crystal structures of Os(2,5-xylyl)4 (Os2) and Os3, employing a "tetrahedricity" metric that shows Os3 has a particularly distorted tetrahedral geometry compared to other Ru(aryl)4 and Os(aryl)4 materials. The 1H NMR spectrum of Os3 exhibits significantly broadened features at 298 K that split into distinct resonances at low temperatures, indicative of restricted rotation of the mesityl ligands around the Os-aryl 𝜎-bond. Solution cyclic voltammograms of Os(aryl)4 reveal that the potentials of their known reversible redox features can be fine-tuned by varying the number of ligand methyl substituents, and that Os3 exhibits an additional 1+/2+ redox event not previously observed in this class of compounds. This work aims to help advance the potential application of these relatively underexplored organometallic complexes in established and emerging areas of molecular materials science, such as extended molecular frameworks and self-assembled monolayers, where analogous tetraphenylmethane and silane species (M = C, Si) have been frequently targeted. Osmium ; Aryl ; Chemistry ; Redox ; Ligand (biochemistry) ; Reactivity (psychology) ; Crystallography ; Ruthenium ; Medicinal chemistry ; Stereochemistry ; Inorganic chemistry ; Catalysis ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Catalytic Cross-Coupling Reactions ; Covalent Organic Framework Applications
Authors: E. Parma | Laura Menezes | Sidnei Baldin | Raphael Nagao
Source: Química Nova (article, 2021-01-01)
Field: Chemistry — Electrochemistry

DESENVOLVIMENTO DE SOFTWARE E INTERFACE PARA O CONTROLE POR RETROALIMENTAÇÃO ATRASADA EM SISTEMAS ELETROQUÍMICOS DEVELOPMENT OF SOFTWARE AND INTERFACE FOR DELAYED FEEDBACK CONTROL IN ELECTROCHEMICAL SYSTEMS. In this paper, we show the development of a LabVIEW algorithm able to apply the delayed feedback control on oscillatory electrochemical reactions. The coupling of the control and the experiments was carried out by a real-time apparatus, measuring the faradaic current and, in sequence, applying a calculated circuit voltage as an analog output. The setup was used to control the oscillatory Cu/Sn electrodeposition dynamics, used as a model-system, and the results clearly demonstrate the control accuracy. Overall, the code may be a great tool for the controlled synthesis of nanomaterials in different oscillatory electrodeposition reactions, as it offers the ability to control the composition and structure of the deposit by fine tuning the dynamic properties. Interface (matter) ; Coupling (piping) ; Voltage ; Software ; Electrochemistry ; Computer science ; Control system ; Materials science ; Control theory (sociology) ; Control (management) ; Electrode ; Physics ; Engineering ; Electrical engineering Electrochemical Analysis and Applications
Authors: Mohamad Nur Zharif Mohamad | S. N. Sabki | Noraini Othman | Norzilah Abdul Halif | Mohd Shafiq Hafly Shamsuri | Norhayati Sabani
Source:  (article, 2021-09-22)
Field: Materials Science — Materials Chemistry

Synthesis of Carbon Nanotubes with Unintentional Secondary Growth of Carbon Nanofibers on Graphene The graphene-carbon nanotubes (CNTs) hybrid structures are known to be promising in improving typical electrodes and on-chip interconnect materials, such as copper and tungsten. This work was initially carried out to grow CNTs on graphene on copper (Cu) foil in CVD at 800°C with reaction time of 20 and 30 mins. However, the experiment has unintentionally grown secondary carbon nanofibers (CNFs) in clusters. Both the 20 and 30 mins reaction time has been found to produce CNTs with secondary growth of CNFs. However, the distribution and the size of clusters are different. Based on the results obtained, the growth process and parameters can be further fine-tuned to obtain a controlled formation of CNTs and CNFs. Carbon nanofiber ; Materials science ; Graphene ; Carbon nanotube ; Nanotechnology ; Tungsten ; Carbon fibers ; Copper ; Nanofiber ; Nanomaterials ; FOIL method ; Interconnection ; Chemical engineering ; Composite material ; Metallurgy ; Composite number Carbon Nanotubes in Composites ; Graphene research and applications ; Supercapacitor Materials and Fabrication
Authors: Camila Jones
Source: Organic chemistry : an Indian journal (article, 2021-01-01)
Field: Chemistry — Organic Chemistry

Synthesis of Asymmetric Cyanine Dyes in Solid State Cyanine Dyes (CD) are a type of organic molecule utilised in a variety of applications, including photography and bioimaging. High molar extinction coefficients up to 105 L mol-1cm-1 and absorption spectra spanning from 500 nm to 1000 nm are the most well-known properties of CDs, which can be fine-tuned by lengthening the length of the central methylene bridge or altering the terminal heterocycles. New synthetic approaches, such as microwave-assisted and solid-phase procedures, have been developed in recent decades to address the limitations of traditional synthetic processes. While the microwave method lowers the time that reagents and products are exposed to thermal deterioration, the solid-phase method allows for simpler synthetic methods, which results in higher yields and easier product purification. The current study provides a thorough examination of solid-phase methods for the synthesis of asymmetrical CDs, as well as a critical assessment of the differences between the currently available solid-state methodologies. Cyanine Dyes (CD) are an organic functional dye with a chemical structure in which two nitrogen atoms are joined by a single or multiple methane group to generate a delocalized system with an odd number of atoms. Cyanine ; Delocalized electron ; Absorption (acoustics) ; Reagent ; Phase (matter) ; Microwave ; Chemistry ; Solid-state ; Molecule ; Materials science ; Combinatorial chemistry ; Nanotechnology ; Fluorescence ; Organic chemistry ; Physical chemistry ; Computer science ; Optics ; Telecommunications Synthesis and Characterization of Heterocyclic Compounds ; Click Chemistry and Applications ; Various Chemistry Research Topics
Authors: Александр Сергеевич Чернуха | Анастасия Александровна Зверева | G. M. Zirnik | Карина Эльвировна Мустафина | D. Pashnin | Ольга Вадимовна Дюкова | Егор Викторович Малёв | Анастасия Владимировна Вепрева | Валерия Вячеславовна Крошнина | N. S. Nekorysnova | В.Е. Живулин | Татьяна Владимировна Мосунова | Д.А. Винник
Source:  (article, 2021-09-18)
Field: Materials Science — Materials Chemistry

Использование метода самовозгорания для получения замещённого алюминием гексаферрита бария Oxide materials have traditionally attracted the attention of researchers around the world. This is due to their wide range of applications: electrical engineering, electronics, special coatings, chemical technologies, etc. Doping of oxide materials with various elements such as Al, Bi, Zn, Co, Sn, Ti, B, Sb and others is widespread in order to fine-tune their physicochemical properties. In particular, doping of barium hexaferrite with aluminum is of particular interest, since this allows one to change such important parameters as saturation magnetization (σS), coercive force (HC), squareness coefficient of the hysteresis loop (K), as well as to influence the anisotropy field and microwave properties of the material. Since the preparation of BaAl x Fe 12-x O 19 by the classical ceramic method requires thorough grinding of the starting materials, preliminary sintering, high temperature (above 1300 °C) and duration of the synthesis, it was decided to test an alternative method for obtaining aluminum-substituted barium hexaferrite. As such, we have chosen the self-combustion method. During the synthesis a solution of nitrates of the corresponding metals with citric acid was prepared. After neutralization and evaporation of the solution, the resulting mass was heated in a muffle furnace to carry out the spontaneous combustion process and remove residual carbon. The final sintering of samples with the composition BaAl x Fe 12-x O 19 (for x = 0, 1, 2, and 3) was carried out in a muffle furnace with a precision temperature controller at 1100 °C for 4 hours. The obtained samples were studied by the powder diffractometry method, scanning electron microscopy, and X-ray spectral microanalysis. It has been established that the self-ignition method makes it possible to obtain homogeneous samples of barium hexaferrite substituted with aluminum at a lower temperature compared to the classical ceramic method. The parameters of the structure of the obtained samples were also determined. The tested method not only makes it possible to obtain aluminum-substituted barium hexaferrite at lower temperatures, but also makes it possible to dope ferrites with highly volatile elements. Muffle furnace ; Materials science ; Coercivity ; Sintering ; Ceramic ; Calcination ; Metallurgy ; Temperature coefficient ; Chemical engineering ; Composite material ; Chemistry Magnetic Properties and Synthesis of Ferrites ; Pigment Synthesis and Properties ; Electromagnetic wave absorption materials
Authors: Joseph M. Parr | Clarissa Olivar | Thomas Saal | Ralf Haiges | Michael S. Inkpen
Source:  (preprint, 2021-11-01)
Field: Chemistry — Inorganic Chemistry

An improved route to osmium(IV) tetraaryl complexes Investigations into the reactivity, properties, and applications of osmium(IV) tetraaryl complexes have been hampered by their low yielding syntheses from volatile and toxic OsO4 (typically ≤34%). Here we show that air-stable M(aryl)4 compounds (M = Os, Ru; aryl = 2-tolyl, 2,5-xylyl) can be prepared in improved yields (≤73%) starting from new, less hazardous (Oct4N)2[MX6] precursors (M = Os, Ru; X = Cl, Br). This approach also facilitates the preparation of Os(mesityl)4 (Os3), a complex comprising bulky 2,6-methyl substituted aryl ligands, for the first time (5% yield). We evaluate the X-ray crystal structures of Os(2,5-xylyl)4 (Os2) and Os3, employing a "tetrahedricity" metric that shows Os3 has a particularly distorted tetrahedral geometry compared to other Ru(aryl)4 and Os(aryl)4 materials. The 1H NMR spectrum of Os3 exhibits significantly broadened features at 298 K that split into distinct resonances at low temperatures, indicative of restricted rotation of the mesityl ligands around the Os-aryl 𝜎-bond. Solution cyclic voltammograms of Os(aryl)4 reveal that the potentials of their known reversible redox features can be fine-tuned by varying the number of ligand methyl substituents, and that Os3 exhibits an additional 1+/2+ redox event not previously observed in this class of compounds. This work aims to help advance the potential application of these relatively underexplored organometallic complexes in established and emerging areas of molecular materials science, such as extended molecular frameworks and self-assembled monolayers, where analogous tetraphenylmethane and silane species (M = C, Si) have been frequently targeted. Osmium ; Aryl ; Chemistry ; Redox ; Ligand (biochemistry) ; Reactivity (psychology) ; Crystallography ; Stereochemistry ; Medicinal chemistry ; Ruthenium ; Catalysis ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Catalytic Cross-Coupling Reactions ; Covalent Organic Framework Applications
Authors: P Rajamalli | Federica Rizzi | Wenbo Li | Michael A. Jinks | Abhishek Gupta | Beth A. Laidlaw | Ifor D. W. Samuel | Thomas J. Penfold | Stephen M. Goldup | Eli Zysman‐Colman
Source: ChemRxiv (preprint, 2021-02-04)
Field: Materials Science — Materials Chemistry

Using the Mechanical Bond to Tune the Performance of a Thermally Activated Delayed Fluorescence Emitter We report the characterization of rotaxanes based on a carbazole–benzophenone thermally activated delayed fluorescence luminophore. We find that the mechanical bond leads to an improvement in key photophysical properties of the emitter, notably an increase in photoluminescence quantum yield and a decrease in the energy difference between singlet and triplet states, as well as fine tuning of the emission wavelength, a feat that is difficult to achieve when using covalently bound substituents. Computational simulations, supported by X-ray crystallography, suggest that this tuning of properties occurs due to weak interactions between the axle and the macrocycle that are enforced by the mechanical bond. This work highlights the benefits of using the mechanical bond to refine existing luminophores, providing a new avenue for emitter optimization that can ultimately increase the performance of these molecules. Carbazole ; Benzophenone ; Common emitter ; Covalent bond ; Fluorescence ; Materials science ; Photoluminescence ; Quantum yield ; Photochemistry ; Luminophore ; Bond energy ; Singlet state ; Molecule ; Nanotechnology ; Optoelectronics ; Chemistry ; Luminescence ; Excited state ; Optics ; Atomic physics ; Organic chemistry ; Physics Luminescence and Fluorescent Materials ; Supramolecular Chemistry and Complexes ; Molecular Junctions and Nanostructures
Authors: Shahar Tevet | Shreyas Shankar Wagle | Gadi Slor | Roey J. Amir
Source: ChemRxiv (article, 2021-06-01)
Field: Materials Science — Polymers and Plastics

Tuning Reactivity of Micellar Nanoreactors by Precise Adjustments of the Amphiphiles and Substrates Hydrophobicity Polymeric assemblies, such as micelles, are gaining increasing attention due to their ability to serve as nanoreactors for the execution of organic reactions in aqueous media. The ability to conduct transformations, which have been limited to organic media, in water is essential for the further development of the important fields of greencatalysis and bioorthogonal chemistry, among other fields. In light of the recent progress in the expanding the scopes of reactions that can be conducted using nanoreactors, we aimed to gain deeper understanding of the roles of the hydrophobicity of both the core of micellar nanoreactors and the substrates on the reaction rates in water. Towards this goal we designed a set of metal-loaded micelles, composed of PEG-dendron amphiphiles and studied their ability to serve as nanoreactors for a palladium mediated depropargylation reaction of four substrates with different LogP values. Using dendrons as the hydrophobic block, allowed us to fine tune the lipophilicity of the dendritic end-groups and study how precise structural changes in the hydrophobicity of the amphiphiles affect the reaction rates. The kinetic data revealed linear relations between the rate constants and the hydrophobicity of the amphiphiles (estimated by the dendron’scLogP), while exponential dependence was obtained for the lipophilicity of the substrates (estimated by their LogP values). Our results demonstrate the vital contributions of the hydrophobicity of both the substrates and amphiphiles on the lipo-selectivity of nanoreactors, illustrating the potential of tuning hydrophobicity as a tool for optimizingthe reactivity and selectivity of nanoreactors. Nanoreactor ; Amphiphile ; Chemistry ; Micelle ; Lipophilicity ; Dendrimer ; Reactivity (psychology) ; Combinatorial chemistry ; Bioorthogonal chemistry ; Organic chemistry ; Aqueous solution ; Copolymer ; Click chemistry ; Catalysis ; Polymer Dendrimers and Hyperbranched Polymers ; Click Chemistry and Applications ; Chemical Synthesis and Analysis
Authors: Shrikrishna H Gurlhosur
Source: INTERNATIONAL RESEARCH JOURNAL OF ENGINEERING AND APPLIED SCIENCES (article, 2021-12-31)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Synthesis and Characterization of Copper Nanoparticles: Investigating Antibacterial Potential via Size and Surface Charge Modulations This research delves into a comprehensive investigation of copper nanoparticle synthesis and characterization, with a specific emphasis on exploring their antibacterial potential by manipulating size and surface charge. Employing a customized approach, precise control over nanoparticle dimensions and surface properties was achieved. Variations in size were attained by fine-tuning reaction parameters, while surface charge modifications were implemented through ligand functionalization. Thorough characterization using diverse analytical techniques, such as transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential measurements, and Fourier-transform infrared spectroscopy (FT-IR), was conducted to elucidate morphological aspects and surface features. This multifaceted characterization aimed to provide a comprehensive understanding of the synthesized copper nanoparticles. Antibacterial assessments against various bacterial strains, spanning Gram-positive and Gram-negative species, were carried out, and the results were meticulously correlated with variations in nanoparticle size and surface charge. The outcomes not only advance the knowledge of copper nanoparticle synthesis but also shed light on the intricate relationship between nanoparticle properties and their antibacterial efficacy. This research holds promise for the development of tailored antibacterial agents with specific physicochemical properties, offering potential applications in antimicrobial materials and biomedical interventions, contributing to the evolving landscape of nanotechnology-driven solutions for combating bacterial infections. Characterization (materials science) ; Copper ; Nanoparticle ; Surface charge ; Nanotechnology ; Materials science ; Charge (physics) ; Surface modification ; Chemistry ; Chemical engineering ; Physics ; Physical chemistry ; Metallurgy ; Engineering Gold and Silver Nanoparticles Synthesis and Applications