jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Yizhen Chen | Rachita Rana | Tyler Sours | Fernando D. Vila | Shaohong Cao | Thomas Blum | Jiyun Hong | Adam S. Hoffman | Chia‐Yu Fang | Zhennan Huang | Chunyan Shang | Chuanhao Wang | Jie Zeng | Miaofang Chi | Coleman X. Kronawitter | Simon R. Bare | Bruce C. Gates | Ambarish Kulkarni
Source: ChemRxiv (preprint, 2021-09-22)
Field: Materials Science — Surfaces, Coatings and Films

A Theory-guided X-ray Absorption Spectroscopy Approach for Identifying Active Sites in Atomically Dispersed Transition Metal Catalysts Atomically dispersed supported metal catalysts offer new properties and the benefits of maximized metal accessibility and utilization. The characterization of these materials, however, remains challenging. Using atomically-dispersed Pt supported on crystalline MgO (chosen for its well-defined bonding sites for Pt) as a prototypical example, in this work, we demonstrate how systematic density functional theory calculations (for assessing all the potentially stable Pt sites) combined with automated EXAFS analysis can lead to unbiased identification of isolated, surface-enveloped platinum cations as the catalytic species for CO oxidation. The catalyst has been characterized by atomic-resolution imaging, EXAFS, and HERFD-XANES spectroscopies; the proposed Pt site are in full agreement with experiment. This theory-guided workflow leads to rigorously determined structural models and provides a more detailed picture of the structure of the catalytically active sites than what is currently possible with conventional EXAFS analysis. As this approach is efficient and agnostic to the metal, support, and catalytic reaction, we posit that it will be of broad interest to the materials characterization and catalysis communities. Extended X-ray absorption fine structure ; Catalysis ; XANES ; Characterization (materials science) ; Density functional theory ; Materials science ; Transition metal ; Metal ; X-ray absorption spectroscopy ; Platinum ; Absorption spectroscopy ; Spectroscopy ; X-ray absorption fine structure ; Absorption (acoustics) ; X-ray spectroscopy ; Chemical physics ; Nanotechnology ; Crystallography ; Chemistry ; Computational chemistry ; Physics ; Organic chemistry ; Optics Electron and X-Ray Spectroscopy Techniques ; X-ray Spectroscopy and Fluorescence Analysis ; X-ray Diffraction in Crystallography
Authors: Omri Abarbanel | Julisa Rozon | Geoffrey Hutchison
Source: ChemRxiv (preprint, 2021-11-14)
Field: Materials Science — Polymers and Plastics

Strategies for Computer-Aided Discovery of Novel Open-Shell Polymers Organic π-conjugated polymers with a triplet ground state have been the focus of recent research for their interesting and unique electronic properties, arising from the presence of the two unpaired electrons. These polymers are usually built from alternating electron-donating and electron-accepting monomer pairs which lower the HOMO-LUMO gap and yield a triplet state instead of the typical singlet ground state. In this paper we use density functional theory calculations to explore the design rules that govern the creation of a ground state triplet conjugated polymer, and find that a small HOMO-LUMO gap in the singlet state is the best predictor for the existence of a triplet ground state, compared to previous use of pro-quinoidal character. This work can accelerate the discovery of new stable triplet materials by reducing the computa- tional resources needed for electronic-state calculations and the number of potential candidates for synthesis. Ground state ; Singlet state ; Conjugated system ; HOMO/LUMO ; Triplet state ; Density functional theory ; Polymer ; Open shell ; Unpaired electron ; Electron ; Monomer ; Materials science ; Chemical physics ; Chemistry ; Computational chemistry ; Physics ; Atomic physics ; Molecule ; Excited state ; Quantum mechanics ; Organic chemistry Conducting polymers and applications ; Organic and Molecular Conductors Research ; Perovskite Materials and Applications
Authors: Mohsen Sotoudeh | Axel Groß
Source: Research Square (preprint, 2021-06-01)
Field: Materials Science — Materials Chemistry

Descriptor and scaling relations for ion mobility in crystalline solids Abstract Ion mobility is a critical performance parameter in electrochemical energy storage and conversion, but also in other electrochemical devices. Based on first-principles electronic structure calculations, we have derived a descriptor for the ion mobility in battery electrodes and solid electrolytes. This descriptor is entirely composed of observables that are easily accessible: ionic radii, oxidation states and the Pauling electronegativities of the involved species. Within a particular class of materials, the migration barriers are connected to this descriptor through linear scaling relations upon the variation of either the cation chemistry of the charge carriers or the anion chemistry of the host lattice. The validity of these scaling relations indicates that a purely ionic view falls short of capturing all factors influencing ion mobility in solids.The identification of these scaling relations has the potential to significantly accelerate the discovery of materials with desired mobility properties. Scaling ; Ion ; Statistical physics ; Chemical physics ; Materials science ; Physics ; Mathematics ; Geometry ; Quantum mechanics Thermal and Kinetic Analysis ; Solid-state spectroscopy and crystallography ; X-ray Diffraction in Crystallography
Authors: Anamaria Todea | Caterina Deganutti | Mariachiara Spennato | Fioretta Asaro | Zingone Guglielmo | Tiziana Milizia | Lucia Gardossi
Source: Zenodo (CERN European Organization for Nuclear Research) (article, 2021-11-24)
Field: Chemistry — Organic Chemistry

Azelaic Acid: A Bio-Based Building Block for Biodegradable Polymers Abstract: Azelaic acid is a dicarboxylic acid containing nine C atoms, industrially obtained from oleic<br> acid. Besides its important properties and pharmacological applications, as an individual compound,<br> azelaic acid has proved to be a valuable bio-based monomer for the synthesis of biodegradable and<br> sustainable polymers, plasticizers and lubricants. This review discusses the studies and the state<br> of the art in the field of the production of azelaic acid from oleic acid, the chemical and enzymatic<br> synthesis of bio-based oligo and polyester and their properties, including biodegradability and<br> biocompostability. Azelaic acid ; Block (permutation group theory) ; Polymer ; Polymer science ; Chemistry ; Materials science ; Organic chemistry ; Mathematics Plant-Derived Bioactive Compounds ; biodegradable polymer synthesis and properties
Authors: Srinivasa Kartik Nemani | BOWEN ZHANG | Brian C. Wyatt | Zachary D. Hood | Sukriti Manna | Rasoul Khaledialidusti | Weichen Hong | Michael Sternberg | Subramanian Sankaranarayanan | Babak Anasori
Source: ChemRxiv (preprint, 2021-04-01)
Field: Materials Science — Materials Chemistry

High-Entropy 2D Carbide MXenes Two-dimensional (2D) transition metal carbides and nitrides, known as MXenes, are a fast-growing family of 2D materials. MXenes 2D flakes have n + 1 (n = 1 – 4) atomic layers of transition metals interleaved by carbon/nitrogen layers, but to-date remain limited in composition to one or two transition metals. In this study, through the use of four transition metals, we report the synthesis of multi-principal element high-entropy M4C3Tx MXenes. Specifically, we introduce two high-entropy MXenes, TiVNbMoC3Tx and TiVCrMoC3Tx, as well as their precursor TiVNbMoAlC3 and TiVCrMoAlC3 high-entropy MAX phases. We used a combination of real and reciprocal space characterization (x-ray diffraction, x-ray photoelectron spectroscopy, energy dispersive x-ray spectroscopy, and scanning transmission electron microscopy) to establish the structure, phase purity, and equimolar distribution of the four transition metals in high-entropy MAX and MXene phases. We use first-principles calculations to compute the formation energies and explore synthesizability of these high-entropy MAX phases. We also show that when three transition metals are used instead of four, under similar synthesis conditions to those of the four-element MAX phase, two different MAX phases can be formed (i.e. no pure single-phase forms). This finding indicates the importance of configurational entropy in stabilizing the desired single-phase high-entropy MAX over multiphases of MAX, which is essential for the synthesis of phase-pure high-entropy MXenes. The synthesis of high-entropy MXenes significantly expand the compositional variety of the MXene family to further tune their properties, including electronic, magnetic, electrochemical, catalytic, high temperature stability, and mechanical properties. MXenes ; Transition metal ; Carbide ; Entropy (arrow of time) ; Materials science ; MAX phases ; Phase transition ; Thermodynamics ; Crystallography ; Chemistry ; Physics ; Nanotechnology ; Metallurgy MXene and MAX Phase Materials ; 2D Materials and Applications
Authors: Umatur Rehman | Asim Mansha | Muhammad Zahid | Sadia Asim | Ameer Fawad Zahoor | Zulfiqar Ahmad Rehan
Source: Research Square (preprint, 2021-12-14)
Field: Chemistry — Organic Chemistry

Quantum Mechanical Modeling Unveil the Effect of Substitutions on the Activation Barriers of the Diels-Alder Reactions of an Antiviral Compound 7H-Benzo[a]phenalene Abstract Density functional theory has been utilized for exploring the mechanism of Diels-Alder reaction between 7 H -benzo[ a ]phenalene and maleic anhydride. 7 H -Benzo[ a ]phenalene is an antiviral compound and information available about its cycloaddition reactions with possible reaction path and mechanism is scarce. In order to work on the synthesis of its further potential derivatives, the mechanism of its reaction with all aspects should be well understood. Two novel intermediates involved in this reaction have been reported. Diels-Alder reaction of maleic anhydride has found many applications in the synthesis of wide range of useful products. The major concern of this work is to evaluate the consequences of introducing electron donating and electron withdrawing substituents on the reactivity of maleic anhydride towards 7 H -benzo[ a ]phenalene. Thermodynamic parameters, activation parameters, energies of frontier orbitals, global reactivity indices and global electron density transfer (GEDT) have been determined for all the reactions. Fukui functions are computed for each reactant in order to identify the most reactive sites. All the reactions have been found to proceed via normal electron demand having polar nature. The substituents with opposite electronic properties were expected to affect the reactivity of dienophile in an inverse manner, however, the results are not according to this assumption. Rather, both kinds of substituents increased the activation barrier of the reaction. This behavior has been explained in the light of various parameters such as the stability of reacting species, gap of frontier molecular orbitals etc. Experimental studies reported previously are in agreement with these results. Chemistry ; Diels–Alder reaction ; Quantum chemical ; Alder ; Organic chemistry ; Catalysis ; Biology ; Molecule ; Botany Organic Chemistry Cycloaddition Reactions ; Photochemistry and Electron Transfer Studies ; Synthesis and Properties of Aromatic Compounds
Authors: Noha Ali Abdel Hady
Source:  (preprint, 2021-05-24)
Field: Materials Science — Biomaterials

Novel green biodegradable polylactide based polyurethane triblock copolymers reinforced with cellulose nanowhiskers Novel green classes of biodegradable polylactide-based triblock polyurethane (TBPU) polymers were synthesized. Owing to their tailored mechanical properties, improved degradation rates, and the enhance cell attachment potential compared with polylactide-homopolymer, they tested for biomedical applications. Triblock copolymers (TB) of different lactide and polyethylene glycol composition were first fabricated by ring-opening polymerization using tin octoate as catalyst. Afterwich polycaprolactone diole (PCL-diole) is reacted with TB copolymers using 1,4-butane diisocyanate (BDI) as nontoxic chain extender to form the final TBPUs. Final composition, molecular weight, thermal properties, hydrophilicity and biodegradation of the obtained TB and TBPU were studied and characterized using 1H-NMR, GPC, FTIR, DSC, SEM and contact angle measurements. Results obtained from the high molecular weight members of TBPUs showed improved hydrophilicity and degradation rates along with tailored mechanical properties. Nanocomposites obtained by reinforcing TBPU3 with 7% (w/w) BCNW showed ~16% increase in tensile strength and 330% in % elongation compared with PL-homopolymer. Those polymers and their nanocomposites demonstrated promising potential to be used as bone cement, and in regenerative medicin. Materials science ; Polycaprolactone ; Polyurethane ; Copolymer ; Ultimate tensile strength ; Polymer ; Nanocomposite ; Chemical engineering ; Cellulose ; Polymer chemistry ; Contact angle ; Polyethylene glycol ; Composite material biodegradable polymer synthesis and properties ; Polymer composites and self-healing ; Carbon dioxide utilization in catalysis
Authors: Jesús N. Pedroza‐Montero | Ignacio L. Garzón | Huziel E. Sauceda
Source: Communications Chemistry (preprint, 2021-07-05)
Field: Materials Science — Materials Chemistry

On the forbidden graphene’s ZO (out-of-plane optic) phononic band-analog vibrational modes in fullerenes The study of nanostructures' vibrational properties is at the core of nanoscience research. They are known to represent a fingerprint of the system as well as to hint the underlying nature of chemical bonds. In this work, we focus on addressing how the vibrational density of states (VDOS) of the carbon fullerene family (C<sub>n</sub>: n = 20 → 720 atoms) evolves from the molecular to the bulk material (graphene) behavior using density functional theory. We find that the fullerene's VDOS smoothly converges to the graphene characteristic line-shape, with the only noticeable discrepancy in the frequency range of the out-of-plane optic (ZO) phonon band. From a comparison of both systems we obtain as main results that: (1) The pentagonal faces in the fullerenes impede the existence of the analog of the high frequency graphene's ZO phonons, (2) which in the context of phonons could be interpreted as a compression (by 43%) of the ZO phonon band by decreasing its maximum allowed radial-optic vibration frequency. And 3) as a result, the deviation of fullerene's VDOS relative to graphene may hold important thermodynamical implications, such as larger heat capacities compared to graphene at room-temperature. These results provide insights that can be extrapolated to other nanostructures containing pentagonal rings or pentagonal defects. Graphene ; Phonon ; Fullerene ; Materials science ; Context (archaeology) ; Condensed matter physics ; Density functional theory ; Molecular vibration ; Nanostructure ; Band gap ; Nanotechnology ; Physics ; Optoelectronics ; Optics ; Quantum mechanics ; Raman spectroscopy Carbon Nanotubes in Composites ; Fullerene Chemistry and Applications ; Graphene research and applications
Authors: Jingru Lu | Sofia Donnecke | Irina Paci | David C. Leitch
Source: ChemRxiv (preprint, 2021-06-18)
Field: Chemistry — Organic Chemistry

A general reactivity map for predicting outcomes in palladium-catalyzed cross-coupling Making accurate, quantitative predictions of chemical reactivity based on molecular structure is an unsolved problem in chemical synthesis, particularly for complex molecules. We report a generally applicable and mechanistically based structure-reactivity model for the oxidative addition of (hetero)aryl halides to palladium(0), which is a key step in myriad catalytic processes. This model links simple molecular descriptors – electrostatic potential, steric parameters, and bond strengths – to relative rates of oxidative addition for 71 electrophile substrates. Because oxidative addition often controls the rate and/or selectivity of palladium-catalyzed cross-coupling reactions, this model can be used to make predictions about catalytic reaction outcomes. Demonstrated applications include a quantitative model for the rate of 410 different Sonogashira coupling reactions, and successful site-selectivity predictions for a series of multihalogenated substrates relevant to the synthesis of pharmaceuticals and natural products. Sonogashira coupling ; Steric effects ; Reactivity (psychology) ; Palladium ; Chemistry ; Catalysis ; Oxidative addition ; Electrophile ; Aryl ; Aryl halide ; Combinatorial chemistry ; Computational chemistry ; Selectivity ; Coupling reaction ; Reaction rate ; Organic chemistry Catalytic Cross-Coupling Reactions ; Catalytic C–H Functionalization Methods ; Cyclopropane Reaction Mechanisms
Authors: Jessica Wahlers | Jèssica Margalef | Eric Hansen | Armita Bayesteh | Paul Helquist | Montserrat Diéguez | Òscar Pàmies | Olaf Wiest | Per‐Ola Norrby
Source: ChemRxiv (preprint, 2021-05-06)
Field: Chemistry — Inorganic Chemistry

Proofreading Experimentally Assigned Stereochemistry Through Q2MM Predictions in Pd-Catalyzed Allylic Aminations We present a modelling method which can predict the enantioselectivity of Pd-catalyzed allylic amination with P,N-ligands. The Q2MM method employed here is accurate enough to identify errors in enantiomer assignment from literature data. Amination ; Allylic rearrangement ; Proofreading ; Enantiomer ; Catalysis ; Chemistry ; Combinatorial chemistry ; Stereochemistry ; Organic chemistry ; Enzyme Asymmetric Hydrogenation and Catalysis ; Machine Learning in Materials Science ; Topic Modeling
Authors: Eibar Flores | Nataliia Mozhzhukhina | Xinyu Li | Poul Norby | Aleksandar Matic | Tejs Vegge
Source:  (preprint, 2021-10-05)
Field: Chemistry — Electrochemistry

PRISMA: A robust and intuitive tool for high-throughput processing of chemical spectra The popularization of high-throughput spectroscopies to characterize functional materials requires the simultaneous development of new analysis tools to efficiently process large numbers of measurements into scientifically meaningful observables. Here we introduce PRISMA, an open-source tool to rapidly analyze hundreds of spectra in a semi-automated way. PRISMA follows a human-in-the-loop workflow, where the user interacts with an intuitive graphical user interface (GUI) to control multiple steps in the spectrum analysis process: trimming, baseline correction, and peak fitting. The user tunes the analysis in real-time and applies the optimal parameters to all spectra, outputting processed results in an easy-to-read csv format within seconds. Crucially, the tuned parameters are stored to guarantee the full reproducibility of the analysis. We describe the functionalities implemented in PRISMA and test its capabilities with three experimental cases relevant to the study of electrochemical energy storage and conversion devices: temperature-dependent Raman measurement of phase transitions, a linear Raman mapping of a graphite composite electrode, and an operando X-ray diffraction experiment of LiNiO2 Li-ion electrode. Even if X-ray diffraction is not a spectroscopic technique, diffraction patterns are represented as one-dimensional arrays of counts equally suitable for analysis with PRISMA. The case studies demonstrate the robustness of the app and its ability to unearth insightful trends in peak parameters, which are easier to represent, interpret and further analyze with more advanced techniques. Computer science ; Graphical user interface ; Robustness (evolution) ; Raman spectroscopy ; Workflow ; Diffraction ; Electrode ; Throughput ; Optics ; Chemistry ; Physics ; Database Electrochemical Analysis and Applications ; Spectroscopy and Chemometric Analyses ; Electrochemical sensors and biosensors
Authors: Dan Mendels | Juan Pablo
Source: arXiv (Cornell University) (preprint, 2021-08-28)
Field: Materials Science — Materials Chemistry

Collective Variables for Free Energy Surface Tailoring -- Understanding and Modifying Functionality in Systems Dominated by Rare Events We introduce a method for elucidating and modifying the functionality of systems dominated by rare events that relies on the automated tuning of their underlying free energy surface. The proposed approach seeks to construct collective variables (CVs) that encode the essential information regarding the rare events of the system of interest. The appropriate CVs are identified using Harmonic Linear Discriminant Analysis (HLDA), a machine-learning based method that is trained solely on data collected from short ordinary simulations in the relevant metastable states of the system. Utilizing the interpretable form of the resulting CVs, the critical interaction potentials that determine the system's rare transitions are identified and purposely modified to tailor the free energy surface in manner that alters functionality as desired. The applicability of the method is illustrated in the context of three different systems, thereby demonstrating that thermodynamic and kinetic properties can be tractably modified with little to no prior knowledge or intuition. Intuition ; Computer science ; ENCODE ; Rare events ; Construct (python library) ; Context (archaeology) ; Artificial intelligence ; Metastability ; Discriminant ; Machine learning ; Theoretical computer science ; Biological system ; Mathematics ; Physics ; Chemistry Machine Learning in Materials Science ; Complex Network Analysis Techniques ; Quantum many-body systems
Authors: Eibar Flores | Nataliia Mozhzhukhina | Xinyu Li | Poul Norby | Aleksandar Matic | Tejs Vegge
Source: ChemRxiv (preprint, 2021-10-05)
Field: Chemistry — Electrochemistry

PRISMA: A robust and intuitive tool for high-throughput processing of chemical spectra The popularization of high-throughput spectroscopies to characterize functional materials requires the simultaneous development of new analysis tools to efficiently process large numbers of measurements into scientifically meaningful observables. Here we introduce PRISMA, an open-source tool to rapidly analyze hundreds of spectra in a semi-automated way. PRISMA follows a human-in-the-loop workflow, where the user interacts with an intuitive graphical user interface (GUI) to control multiple steps in the spectrum analysis process: trimming, baseline correction, and peak fitting. The user tunes the analysis in real-time and applies the optimal parameters to all spectra, outputting processed results in an easy-to-read csv format within seconds. Crucially, the tuned parameters are stored to guarantee the full reproducibility of the analysis. We describe the functionalities implemented in PRISMA and test its capabilities with three experimental cases relevant to the study of electrochemical energy storage and conversion devices: temperature-dependent Raman measurement of phase transitions, a linear Raman mapping of a graphite composite electrode, and an operando X-ray diffraction experiment of LiNiO2 Li-ion electrode. Even if X-ray diffraction is not a spectroscopic technique, diffraction patterns are represented as one-dimensional arrays of counts equally suitable for analysis with PRISMA. The case studies demonstrate the robustness of the app and its ability to unearth insightful trends in peak parameters, which are easier to represent, interpret and further analyze with more advanced techniques. Computer science ; Robustness (evolution) ; Graphical user interface ; Raman spectroscopy ; Workflow ; Diffraction ; Electrode ; Throughput ; Optics ; Chemistry ; Physics Electrochemical Analysis and Applications ; Spectroscopy and Chemometric Analyses ; Electrochemical sensors and biosensors