jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Olga D’Anania | Claudio De Rosa | Giovanni Talarico
Source: Molecules (article, 2023-04-27)
Field: Chemistry — Organic Chemistry

A Computational Evaluation of the Steric and Electronic Contributions in Stereoselective Olefin Polymerization with Pyridylamido-Type Catalysts A density functional theory (DFT) study combined with the steric maps of buried volume (%<i>V</i><sub>Bur</sub>) as molecular descriptors and an energy decomposition analysis through the ASM (activation strain model)-NEDA (natural energy decomposition analysis) approach were applied to investigate the origins of stereoselectivity for propene polymerization promoted by pyridylamido-type nonmetallocene systems. The relationships between the fine tuning of the ligand and the propene stereoregularity were rationalized (e.g., the metallacycle size, chemical nature of the bridge, and substituents at the <i>ortho</i>-position on the aniline moieties). The DFT calculations and %<i>V</i><sub>Bur</sub> steric maps reproduced the experimental trend: substituents on the bridge and on the <i>ortho</i>-positions of aniline fragments enhance the stereoselectivity. The ASM-NEDA analysis enabled the separation of the steric and electronic effects and revealed how subtle ligand modification may affect the stereoselectivity of the process. Steric effects ; Stereoselectivity ; Chemistry ; Olefin fiber ; Density functional theory ; Ligand (biochemistry) ; Polymerization ; Propene ; Computational chemistry ; Stereochemistry ; Electronic effect ; Catalysis ; Organic chemistry ; Polymer Organometallic Complex Synthesis and Catalysis ; Machine Learning in Materials Science ; Carbon dioxide utilization in catalysis
Authors: Ekaterina D. Koshevaya | Evgeny V. Khramov | Rоman D. Svetogorov | Aleksei G. Krasnov | Ilia S. Martakov | Ivan I. Shishkin | Elena F. Krivoshapkina | Pavel V. Krivoshapkin
Source: Inorganic Chemistry (article, 2023-06-22)
Field: Materials Science — Materials Chemistry

Stokes and Anti-Stokes Luminescent Rare-Earth-Doped Tantalum Oxide Nanoparticles Doping of nano- and microparticles of oxides with rare earth elements (REEs) is used to fine-tune their structural, optical, and electrochemical properties. On the way to establish the structure-property relationship, we dope tantalum oxide (Ta<sub>2</sub>O<sub>5</sub>) particles with REEs to study their effect on the oxide structure and luminescence. Ta<sub>2</sub>O<sub>5</sub> is highly perspective in medicine, catalysis, and optics, but its crystal structure is insufficiently studied. Two synthesis approaches (sol-gel and solvothermal) were used to obtain powders with different textures. Experimental and theoretical studies of amorphous and crystallized tantalum oxide NPs by means of X-ray powder diffraction, Rietveld analysis, EXAFS/XANES spectroscopy, and density functional theory calculations were performed. All samples (doped and undoped) crystallized in orthorhombic phase with no admixtures. It was demonstrated that Ta<sub>2</sub>O<sub>5</sub> is a promising wide-spectrum luminescent material: by combining REEs, both Stokes and anti-Stokes luminescence in the visible region were obtained. By means of optical absorption spectroscopy, it was shown that the prepared samples could be classified as wide band gap semiconductors. Luminescence ; Chemistry ; XANES ; Tantalum ; Orthorhombic crystal system ; Doping ; Extended X-ray absorption fine structure ; Stokes shift ; Oxide ; Nanoparticle ; Absorption spectroscopy ; Powder diffraction ; Rietveld refinement ; Band gap ; Spectroscopy ; Crystal structure ; Nanotechnology ; Materials science ; Crystallography ; Optoelectronics ; Optics ; Organic chemistry Luminescence Properties of Advanced Materials ; Glass properties and applications ; Microwave Dielectric Ceramics Synthesis
Authors: Amir Rudich | Sunaina Sapru | Oded Shoseyov
Source: Nanomaterials (article, 2023-02-24)
Field: Materials Science — Biomaterials

Biocompatible, Resilient, and Tough Nanocellulose Tunable Hydrogels Hydrogels have been proposed as potential candidates for many different applications. However, many hydrogels exhibit poor mechanical properties, which limit their applications. Recently, various cellulose-derived nanomaterials have emerged as attractive candidates for nanocomposite-reinforcing agents due to their biocompatibility, abundance, and ease of chemical modification. Due to abundant hydroxyl groups throughout the cellulose chain, the grafting of acryl monomers onto the cellulose backbone by employing oxidizers such as cerium(IV) ammonium nitrate ([NH<sub>4</sub>]<sub>2</sub>[Ce(NO<sub>3</sub>)<sub>6</sub>], CAN) has proven a versatile and effective method. Moreover, acrylic monomers such as acrylamide (AM) may also polymerize by radical methods. In this work, cerium-initiated graft polymerization was applied to cellulose-derived nanomaterials, namely cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF), in a polyacrylamide (PAAM) matrix to fabricate hydrogels that display high resilience (~92%), high tensile strength (~0.5 MPa), and toughness (~1.9 MJ/m<sup>3</sup>). We propose that by introducing mixtures of differing ratios of CNC and CNF, the composite's physical behavior can be fine-tuned across a wide range of mechanical and rheological properties. Moreover, the samples proved to be biocompatible when seeded with green fluorescent protein (GFP)-transfected mouse fibroblasts (3T3s), showing a significant increase in cell viability and proliferation compared to samples comprised of acrylamide alone. Nanocellulose ; Self-healing hydrogels ; Cellulose ; Materials science ; Biocompatibility ; Monomer ; Nanomaterials ; Nanocomposite ; Chemical engineering ; Acrylamide ; Polymerization ; Polymer chemistry ; Polymer ; Composite material ; Nanotechnology Advanced Cellulose Research Studies ; Electrospun Nanofibers in Biomedical Applications ; Hydrogels: synthesis, properties, applications
Authors: Takashi Harimoto | Takanori Suzuki | Yusuke Ishigaki
Source: Chemistry - A European Journal (article, 2023-01-13)
Field: Materials Science — Polymers and Plastics

Enhancement of NIR‐Absorbing Ability of Bis(diarylmethylium)‐Type Dicationic Dyes Based on an <i>Ortho</i>‐Substitution Strategy. Electrochromic systems capable of switching near-infrared (NIR) absorption are fascinating from the viewpoint of applications in the materials and life sciences. Although 11,11,12,12-tetraaryl-9,10-anthraquinodimethanes (AQDs) with a folded form undergo one-stage two-electron oxidation to produce twisted dicationic dyes exhibiting NIR absorption, there is a need to establish a design strategy that can enhance the NIR-absorbing abilities of the corresponding dicationic dyes. In this study, we designed and synthesized a series of AQD derivatives with various substituents introduced at the ortho-position(s) of the 4-methoxyphenyl group. X-ray and spectroscopic analyses revealed that NIR-absorbing properties can be changed by introduction of the ortho-substituents. Thus, control of the steric and electronic effects of the ortho-substituents on the 4-methoxyphenyl groups was demonstrated to be an effective strategy for fine-tuning of the HOMO and LUMO levels for neutral AQDs and twisted dications, respectively, resulting in the modification of electrochemical and spectroscopic properties under an "ortho-substitution strategy". Electrochromism ; Steric effects ; HOMO/LUMO ; Chemistry ; Absorption (acoustics) ; Electrochemistry ; Photochemistry ; Near-infrared spectroscopy ; Combinatorial chemistry ; Molecule ; Materials science ; Stereochemistry ; Organic chemistry ; Physical chemistry ; Electrode ; Optics Conducting polymers and applications ; Photochromic and Fluorescence Chemistry ; Polydiacetylene-based materials and applications
Authors: Peng Cui | Qiulan Wu
Source: Journal of Photochemistry and Photobiology A Chemistry (article, 2023-09-26)
Field: Materials Science — Materials Chemistry

Computationally engineering optoelectronic properties and photocatalytic performance in graphene quantum dot/platinum(II) complex photocatalysts Chemistry ; HOMO/LUMO ; Graphene ; Photocatalysis ; Density functional theory ; Nanocomposite ; Quantum dot ; Photochemistry ; Graphene quantum dot ; Reactivity (psychology) ; Electron transfer ; Absorption (acoustics) ; Chemical physics ; Molecular orbital ; Electronic structure ; Nanotechnology ; Computational chemistry ; Molecule ; Catalysis ; Materials science ; Organic chemistry ; Composite material Carbon and Quantum Dots Applications ; Quantum Dots Synthesis And Properties ; Nanocluster Synthesis and Applications
Authors: Xiaohe Wei | Fengjun Chun | Feihong Liu | Xin Zhang | Weilin Zheng | Yang Guo | Zhifeng Xing | Haiyan An | Dangyuan Lei | Yu Tang | Chun‐Hua Yan | Feng Wang
Source: Small (article, 2023-09-17)
Field: Materials Science — Materials Chemistry

Interfacing Lanthanide Metal‐Organic Frameworks with ZnO Nanowires for Alternating Current Electroluminescence Alternating current electroluminescence (ACEL) devices are attractive candidates in cost-effective lighting, sensing, and flexible displays due to their uniform luminescence, stable performance, and outstanding deformability. However, ACEL devices have suffered from limited options for the light-emitting layer, which presents a significant constraint in the progress of utilizing ACEL. Herein, a new class of ACEL phosphors based on lanthanide metal-organic frameworks (Ln-MOFs) is devised. A synthesis of lanthanide-benzenetricarboxylate (Ln-BTC) thin film on a brass grid substrate seeded with ZnO nanowires (NWs) as anchors is developed. The as-synthesized Ln-BTC thin film is employed as the emissive layer and shows visible electroluminescence driven by alternating current (2.9 V µm<sup>-1</sup> , 1 kHz) for the first time. Mechanistic investigations reveal that the Ln-based ACEL stems from impact excitation by accelerated electrons from ZnO NWs. Fine-tuning of the ACEL color is also demonstrated by controlling the Ln-MOF compositions and introducing an extra ZnS emitting layer. The advances in these optical materials expand the application of ACEL devices in anti-counterfeiting. Electroluminescence ; Materials science ; Lanthanide ; Phosphor ; Optoelectronics ; Substrate (aquarium) ; Light-emitting diode ; Layer (electronics) ; Metal-organic framework ; Luminescence ; Thin film ; Electroluminescent display ; Nanotechnology ; Alternating current ; Nanowire ; Electrical engineering ; Ion ; Chemistry Luminescence and Fluorescent Materials ; Organic Light-Emitting Diodes Research ; Conducting polymers and applications
Authors: Jianjun Huang | Flip de Jong | Davita M. E. van Raamsdonk | Jonathan B. F. Vandenwijngaerden | Akane Inoue | Daniel Escudero | Luc Van Meervelt | Mark Van der Auweraer | Wim Dehaen
Source: Advanced Optical Materials (article, 2023-08-27)
Field: Materials Science — Materials Chemistry

BOPAM: Efficient Synthesis of a Bright Asymmetric Bis‐Boron Complex and its Dark Side Abstract A new family of unsymmetrical boron chromophores chelated with two BF 2 units, named BOPAM, has been developed via a one‐pot, three‐step reaction starting from commercially available thioamides via i) conversion to amidrazones, ii) condensation with pyrrole aldehydes, and iii) boron chelation. This synthetic pathway has been proven to be highly efficient, having a broad substrate tolerance and giving the BOPAM products high yield. Notably, some of the BOPAM dyes show interesting photophysical properties with fluorescence quantum yields up to 0.98 in toluene. A fine‐tuning of their emissive properties has been attained through tailored molecular design strategies guided by in‐depth computational investigations. Tailored substitution with electron‐donating groups at the BOPAM ring leads to the opening of a non‐radiative decay channel involving a dark state and consequently a significant quenching of the fluorescence. The study is complemented by exhaustive steady‐state and time‐resolved spectroscopic measurements. Chromophore ; Materials science ; Pyrrole ; Boron ; Fluorescence ; Photochemistry ; Toluene ; Quenching (fluorescence) ; Quantum yield ; Yield (engineering) ; Substrate (aquarium) ; Chelation ; Combinatorial chemistry ; Organic chemistry ; Chemistry ; Optics ; Physics Luminescence and Fluorescent Materials ; Perovskite Materials and Applications ; Nanoplatforms for cancer theranostics
Authors: L. E. Corrêa | Pedro P. Ferreira | Leandro R. de Faria | Vitor M. Fim | M. S. da Luz | M. S. Torikachvili | Christoph Heil | Luiz T. F. Eleno | António Machado
Source: The Journal of Physical Chemistry C (article, 2023-03-08)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Superconductivity in Te-Deficient ZrTe<sub>2</sub> We present structural, electrical, and thermoelectric potential measurements on high-quality single crystals of ZrTe<sub>1.8</sub> grown from isothermal chemical vapor transport. These measurements show that the Te-deficient ZrTe<sub>1.8</sub>, which forms the same structure as the nonsuperconducting ZrTe<sub>2</sub>, is superconducting below 3.2 K. The temperature dependence of the upper critical field (H <sub><i>c</i>2</sub>) deviates from the behavior expected in conventional single-band superconductors, being best described by an electron-phonon two-gap superconducting model with strong intraband coupling. For the ZrTe<sub>1.8</sub> single crystals, the Seebeck potential measurements suggest that the charge carriers are predominantly negative, in agreement with the ab initio calculations. Through first-principles calculations within DFT, we show that the slight reduction of Te occupancy in ZrTe<sub>2</sub> unexpectedly gives origin to density of states peaks at the Fermi level due to the formation of localized Zr-<i>d</i> bands, possibly promoting electronic instabilities at the Fermi level and an increase at the critical temperature according to the standard BCS theory. These findings highlight that the Te deficiency promotes the electronic conditions for the stability of the superconducting ground state, suggesting that defects can fine-tune the electronic structure to support superconductivity. Superconductivity ; Condensed matter physics ; Fermi level ; Thermoelectric effect ; Electronic structure ; Seebeck coefficient ; Critical field ; Materials science ; Chemistry ; Electron ; Physics ; Thermodynamics ; Quantum mechanics Iron-based superconductors research ; 2D Materials and Applications ; Inorganic Chemistry and Materials
Authors: Xiaotian Ji | Changying Shi | Dandan Guo | Xiguang Yang | Liye Suo | Juntao Luo
Source: Molecular Pharmaceutics (article, 2023-03-06)
Field: Chemistry — Organic Chemistry

Engineering Telodendrimer Nanocarriers for Monomeric Amphotericin B Delivery Systemic fungal infections are an increasingly prevalent health problem. Amphotericin B (AmB), a hydrophobic polyene antibiotic, remains the drug of choice for life-threatening invasive fungal infections. However, it has dose-limiting side effects, including nephrotoxicity. The efficacy and toxicity of AmB are directly related to its aggregation state. Here, we report the preparation of a series of telodendrimer (TD) nanocarriers with the freely engineered core structures for AmB encapsulation to fine-tune AmB aggregation status. The reduced aggregation status correlates well with the optimized antifungal activity, attenuated hemolytic properties, and reduced cytotoxicity to mammalian cells. The optimized TD nanocarrier for monomeric AmB encapsulation significantly increases the therapeutic index, reduces the <i>in vivo</i> toxicity, and enhances antifungal effects in mouse models with <i>Candida albicans</i> infection in comparison to two common clinical formulations, <i>i.e.</i>, Fungizone and AmBisome. Nanocarriers ; Amphotericin B ; Candida albicans ; Nephrotoxicity ; Toxicity ; Cytotoxicity ; In vivo ; Therapeutic index ; Pharmacology ; Chemistry ; Drug delivery ; Antibiotics ; Drug ; Microbiology ; Antifungal ; Medicine ; In vitro ; Biology ; Biochemistry Antimicrobial agents and applications ; Dendrimers and Hyperbranched Polymers ; Antimicrobial Peptides and Activities
Authors: M. Sivagami | I.V. Asharani
Source: Photochemical & Photobiological Sciences (article, 2023-07-26)
Field: Materials Science — Materials Chemistry

Sunlight-assisted photocatalytic degradation of orange G dye using cost-effective zinc oxide nanoparticles Photocatalysis ; Nanoparticle ; Materials science ; Zinc ; Zeta potential ; Chemical engineering ; Catalysis ; Photodegradation ; Aqueous solution ; Calcination ; Methyl orange ; Hydrogen peroxide ; Nuclear chemistry ; Oxidizing agent ; Nanotechnology ; Chemistry ; Organic chemistry Nanoparticles: synthesis and applications ; TiO2 Photocatalysis and Solar Cells ; Advanced Photocatalysis Techniques
Authors: Adel Jalaee | E. Johan Foster
Source: ACS Sustainable Chemistry & Engineering (article, 2023-12-13)
Field: Materials Science — Polymers and Plastics

Improvement in the Thermomechanical Properties and Adhesion of Wood Fibers to the Polyamide 6 Matrix by Sequential Ball Milling Technique The engineering thermoplastics industry has largely limited the use of natural fiber reinforcements due to their susceptibility to low-onset thermal degradation and water absorption. Therefore, in order to utilize these economically viable and environmentally friendly materials effectively through common composite fabrication methods such as hot pressing, safeguarding them from thermal degradation becomes essential. This work presents a viable industrially technique called sequential ball milling for processing unbleached softwood kraft pulp fibers (PF) with an engineering thermoplastics polyamide 6 (PA6) with high melting temperatures (>220 °C). An additional eco-friendly modification step that employs ball milling and cellulose nanocrystal (CNC) has been implemented in this study to enhance the mechanical properties of the composites. Special attention is given to fine-tuning key variables, such as milling duration and PF particle size, to produce optimal composites. Leveraging the ability of sequential ball milling to evenly distribute pulp fibers into PA6, a 160% increase in Young's modulus was achieved with the incorporation of 30 wt % PF. Importantly, the introduction of a 5 wt % CNC modifying agent elevated Young's modulus to 4.3 GPa, marking a 187% improvement over unmodified PA6. Diverse techniques, including rheological analyses, thermomechanical evaluations, morphological examinations, and assessments of moisture absorption, were utilized to validate the efficiency of the suggested processing approach and the modification phase. Materials science ; Composite material ; Absorption of water ; Ball mill ; Cellulose ; Dynamic mechanical analysis ; Polyamide ; Pulp (tooth) ; Environmentally friendly ; Composite number ; Polymer ; Chemical engineering Natural Fiber Reinforced Composites ; Advanced Cellulose Research Studies ; Lignin and Wood Chemistry
Authors: Rohit Modee | Sarvesh Mehta | Siddhartha Laghuvarapu | U. Deva Priyakumar
Source: The Journal of Physical Chemistry B (article, 2023-11-28)
Field: Materials Science — Materials Chemistry

MolOpt: Autonomous Molecular Geometry Optimization Using Multiagent Reinforcement Learning Most optimization problems require the user to select an algorithm and, to some extent, also tune it for better performance. Although intuition and knowledge about the problem can speed up these selection and fine-tuning processes, users often use trial-and-error methodologies, which can be time-consuming and inefficient. With all of that in mind and much more, the concept of "learned optimizers", "learning to learn", and "meta-learning" has been gathering attention in recent years. In this article, we propose MolOpt that uses multiagent reinforcement learning (MARL) for autonomous molecular geometry optimization (MGO). Typically MGO algorithms are hand-designed, but MolOpt uses MARL to learn a learned optimizer (policy) that can perform MGO without the need for other hand-designed optimizers. We cast MGO as a MARL problem, where each agent corresponds to a single atom in the molecule. MolOpt performs MGO by minimizing the forces on each atom of the molecule. Our experiments demonstrate the generalizing ability of MolOpt for the MGO of propane, pentane, heptane, hexane, and octane when trained on ethane, butane, and isobutane. In terms of performance, MolOpt outperforms the MDMin optimizer and demonstrates performance similar to that of the FIRE optimizer. However, it does not surpass the BFGS optimizer. The results demonstrate that MolOpt has the potential to introduce innovative advancements in MGO by providing a novel approach using reinforcement learning (RL), which may open up new research directions for MGO. Overall, this work serves as a proof-of-concept for the potential of MARL in MGO. Reinforcement learning ; Computer science ; Intuition ; Butane ; Isobutane ; Energy minimization ; Artificial intelligence ; Mathematical optimization ; Mathematics ; Chemistry Machine Learning in Materials Science ; Computational Drug Discovery Methods ; Chemical Synthesis and Analysis
Authors: Mikhail Yu. Afonin | Pavel A. Martynenko | Dmitry S. Kolybalov | Radmir M. Khisamov | Sergey N. Konchenko | Taisiya S. Sukhikh
Source: Inorganic Chemistry (article, 2023-11-21)
Field: Chemistry — Organic Chemistry

Pd(II)- and Pt(II)-Assisted P–C Activation/Cyclization Reactions with a Luminescent α-Aminophosphine There is unceasing interest toward transformations of phosphine derivatives, which are facilitated by transition metals. We report a facile Pd(II)- and Pt(II)-assisted P-C bond cleavage in a luminescent 2-phenylbenzothiazole-based α-methylaminophosphine (<i><b>PCN</b></i>, <b>1</b>). Specifically, reactions between <b>1</b> and [M(COD)Cl<sub>2</sub>] (M = Pd, Pt; COD = cycloocta-1,5-diene) in different solvents (methylene chloride, acetonitrile, pyridine, toluene) resulted in the formation of PPh<sub>2</sub><sup>-</sup>, captured either as a bridging ligand in binuclear complexes with a {M<sub>2</sub>(PPh<sub>2</sub>)<sub>2</sub>} moiety or as an adduct to COD in [Pt<sub>2</sub>(PPh<sub>2</sub>COD)<sub>2</sub>Cl<sub>2</sub>]. The heterocyclic part transforms to annulated <i><b>c-CN</b></i><sup>+</sup> species with a 1,2-dihydroquinazoline cycle formed. In the presence of pyridine as a base, annulated form <i><b>c-CN</b></i><sup>+</sup> destabilizes and undergoes reverse cyclization transforming to deprotonated <i><b>CN</b></i> form. Quantum-chemical density functional theory (DFT) calculations predict that a crucial step in the reactions involves proton transfer from the N atom of the amino group of <i><b>PCN</b></i> to a neighboring molecule. A combination of high photophysical sensitivity of <i><b>c-CN</b></i><sup>+</sup> toward its immediate environment and rich structural capabilities in assembling (<i><b>c-CN</b></i>)<sub>2</sub><sup>2+</sup> pairs in different crystal packings in a family of phases with the general formula (<i><b>c-CN</b></i>)<sub>2</sub>[M<sub>2</sub>(PPh<sub>2</sub>)<sub>2</sub>Cl<sub>4</sub>] allows one to fine-tune the luminescence properties of the latter. The results were rationalized as a variation of π-π intercationic spacings, which tunes the degree of excited-state charge transfer between <i><b>c-CN</b></i><sup>+</sup> cations. As a result, compounds with relatively short interplanar π-π-separation between the cations show a stronger charge-transfer-mediated bathochromic shift. Chemistry ; Pyridine ; Luminescence ; Adduct ; Deprotonation ; Acetonitrile ; Moiety ; Methylene ; Excited state ; Density functional theory ; Ligand (biochemistry) ; Crystallography ; Photochemistry ; Stereochemistry ; Medicinal chemistry ; Computational chemistry ; Organic chemistry Catalytic C–H Functionalization Methods ; Radical Photochemical Reactions ; Catalytic Cross-Coupling Reactions