jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Bethany R. Hood | Yovan de Coene | Claire F. Jones | Ivan Lopez Poves | Noah Deveaux | Nathan R. Halcovitch | Benoı̂t Champagne | Koen Clays | John Fielden
Source: Inorganic Chemistry (article, 2024-12-06)
Field: Materials Science — Materials Chemistry

Synthesis and Optical and Nonlinear Optical Properties of Linear and Two-Dimensional Charge Transfer Chromophores Based on Polyoxometalates We present the first study of arylimido-polyoxometalate nonlinear optical (NLO) chromophores with two-dimensional (2D) structures, and a comparison with one-dimensional analogues, through the synthesis of a family of arylimido-hexamolybdate derivatives where one or two polyoxometalate (POM) acceptors are connected to a tolyl-amino donor through phenyl bridges. Electronic absorption spectra and TD-DFT calculations reveal significant red-shifts in ligand-to-polyoxometalate charge transfer (LPCT) absorption bands for the 2D species compared to linear, dipolar analogues, consistent with the involvement of a larger conjugated (bridge + POM) system in the transitions. Electrochemical measurements indicate reversible, one-electron processes for the POM acceptors with class II mixed valence behavior observed where the POMs are connected to the same aryl ring and electronic isolation of the acceptors when they are on separate rings. Molecular first hyperpolarizabilities β have been determined using hyper-Rayleigh scattering at 1064 and 1200 nm: for the most active compound, the HRS measurements and depolarization studies reveal a strongly 2D, off-diagonal response (β<sub>0,zzz</sub> = 190 × 10<sup>-30</sup> esu; β<sub>0,zyy</sub> = -56.5 × 10<sup>-30</sup> esu), consistent with the wide A-D-A angle and TD-DFT computed electronic transitions, which show both phenyl bridges and POMs equally involved in the acceptor orbitals. Chemistry ; Polyoxometalate ; Chromophore ; Acceptor ; Absorption spectroscopy ; Valence (chemistry) ; Time-dependent density functional theory ; Crystallography ; Density functional theory ; Photochemistry ; Computational chemistry ; Organic chemistry Polyoxometalates: Synthesis and Applications ; Porphyrin and Phthalocyanine Chemistry ; Magnetism in coordination complexes
Authors: Sonia Hadaoui | Giang Tran | Ahmed Naitabdi | Alexa Courty
Source: Nanoscale (article, 2024-12-09)
Field: Chemistry — Organic Chemistry

Versatile role of oleylamine in the controlled synthesis of copper nanoparticles with diverse morphologies Precise tuning of ligands and a comprehensive understanding of their roles and functionalities are crucial for the design of nanoparticles (NPs) with tailored properties. In this study, we present the synthesis of copper NPs with precise control over their shape and crystallinity, relying on the remarkable versatility of oleylamine (OLA) as both a solvent and a ligand. By adjusting the temperature, OLA enables the formation of cubic NPs under rapid heating, reflecting kinetic control, and octahedral NPs with slow heating, indicating thermodynamic control. XPS analysis of these NPs reveals that OLA's dual chemical functionality allows for the stabilization of cubic NP (100) facets through surface binding <i>via</i> its alkene group, while octahedral and quasi-spherical NPs are stabilized by OLA's attachment to (111) facets through its amine function. Besides, this study highlights how trioctyl phosphine oxide (TOPO) and trioctyl phosphine (TOP) contribute to controlling nucleus crystallinity at early synthesis stages, facilitating the selective formation of single-crystal particles or multiply twinned particles. OLA's dual role, as both solvent and ligand, enhances its ability to stabilize different crystalline facets, making it a powerful tool for synthesizing copper NPs with diverse and controlled morphologies. This versatility opens up possibilities for tailoring their catalytic properties to specific applications. Oleylamine ; Copper ; X-ray photoelectron spectroscopy ; Nanoparticle ; Materials science ; Nanotechnology ; Alkene ; Amine gas treating ; Chemical engineering ; Chemistry ; Organic chemistry ; Catalysis ; Metallurgy Nanomaterials for catalytic reactions ; Copper-based nanomaterials and applications ; Catalytic Processes in Materials Science
Authors: Mercedes A. Bettelli | Qisong Hu | Antonio J. Capezza | Eva Johansson | Richard T. Olsson | Mikael S. Hedenqvist
Source: Communications Chemistry (article, 2024-04-03)
Field: Materials Science — Materials Chemistry

Effects of multi-functional additives during foam extrusion of wheat gluten materials To broaden the range in structures and properties, and therefore the applicability of sustainable foams based on wheat gluten expanded with ammonium-bicarbonate, we show here how three naturally ocurring multifunctional additives affect their properties. Citric acid yields foams with the lowest density (porosity of ~50%) with mainly closed cells. Gallic acid acts as a radical scavenger, yielding the least crosslinked/ aggregated foam. The use of a low amount of this acid yields foams with the highest uptake of the body-fluid model substance (saline, ~130% after 24 hours). However, foams with genipin show a large and rapid capillary uptake (50% in one second), due to their high content of open cells. The most dense and stiff foam is obtained with one weight percent genipin, which is also the most crosslinked. Overall, the foams show a high energy loss-rate under cyclic compression (84-92% at 50% strain), indicating promising cushioning behaviour. They also show a low compression set, indicating promising sealability. Overall, the work here provides a step towards using protein biofoams as a sustainable alternative to fossil-based plastic/rubber foams in applications where absorbent and/or mechanical properties play a key role. Genipin ; Extrusion ; Materials science ; Chemical engineering ; Ammonium bicarbonate ; Porosity ; Compression set ; Cushioning ; Citric acid ; Composite material ; Microporous material ; Chemistry ; Raw material ; Chitosan ; Organic chemistry ; Natural rubber Pickering emulsions and particle stabilization ; biodegradable polymer synthesis and properties ; Proteins in Food Systems
Authors: Wan‐Chen Cindy Lee | X. Peter Zhang
Source: Angewandte Chemie (article, 2024-03-13)
Field: Chemistry — Organic Chemistry

Metalloradical Catalysis: General Approach for Controlling Reactivity and Selectivity of Homolytic Radical Reactions Abstract Since Friedrich Wöhler's groundbreaking synthesis of urea in 1828, organic synthesis over the past two centuries has predominantly relied on the exploration and utilization of chemical reactions rooted in two‐electron heterolytic ionic chemistry. While one‐electron homolytic radical chemistry is both rich in fundamental reactivities and attractive with practical advantages, the synthetic application of radical reactions has been long hampered by the formidable challenges associated with the control over reactivity and selectivity of high‐energy radical intermediates. To fully harness the untapped potential of radical chemistry for organic synthesis, there is a pressing need to formulate radically different concepts and broadly applicable strategies to address these outstanding issues. In pursuit of this objective, researchers have been actively developing metalloradical catalysis (MRC) as a comprehensive framework to guide the design of general approaches for controlling over reactivity and stereoselectivity of homolytic radical reactions. Essentially, MRC exploits the metal‐centered radicals present in open‐shell metal complexes as one‐electron catalysts for homolytic activation of substrates to generate metal‐entangled organic radicals as the key intermediates to govern the reaction pathway and stereochemical course of subsequent catalytic radical processes. Different from the conventional two‐electron catalysis by transition metal complexes, MRC operates through one‐electron chemistry utilizing stepwise radical mechanisms. Homolysis ; Chemistry ; Reactivity (psychology) ; Catalysis ; Selectivity ; Photochemistry ; Radical ; Organic chemistry Oxidative Organic Chemistry Reactions ; Catalytic C–H Functionalization Methods ; Radical Photochemical Reactions
Authors: Zhuoran Wang | Thomas Jarrin | Mickaël Rivallan | Isabelle Clémençon | Emmanuel Soyer | Theodorus de Bruin | L. Lemaître | Virgile Rouchon | David Gajan | Gerhard D. Pirngruber | Céline Chizallet | Anne Lesage
Source: ACS Catalysis (article, 2024-12-03)
Field: Chemistry — Inorganic Chemistry

Deciphering Faujasite Zeolite Dealumination at the Atomic Scale Zeolites are widely used as solid acid catalysts from the laboratory to the industrial scale. Their thermal stability, mesoporous volume, and catalytic properties can be significantly enhanced by framework dealumination, resulting in the formation of framework defects and extra-framework aluminum (EFAL) species, altering surface acidity and microporous volume. Understanding dealumination of as-synthesized zeolite crystals is critical to tuning their catalytic activities. However, the atomic-scale structural evolution of the zeolite surface in the course of dealumination treatments remains elusive. Here, we examined a series of four faujasite zeolite samples, ranging from Y to USY zeolites, collected at key steps of the manufacturing process. High-resolution quantitative 1H NMR spectra were obtained at high field and fast magic angle spinning frequency and interpreted with the help of 1H multiple-quantum (up to four-quanta) and 1H–27Al dipolar-based correlation experiments. An extensive array of surface species was resolved, identified, and monitored during dealumination with a high level of structural detail. This was achieved through a joint interpretation of the NMR data acquired across the entire sample set and DFT calculations spanning an exceptionally broad range of environments. Key insight is provided into the environment of various hydroxyl groups as well as the atomic-scale structure of mononuclear EFAL species. While alumina-like domains are not observed, the presence of multinuclear EFAL species is evidenced. The structures of several defect silanol sites were also characterized. The quantitative evolution of these various surface sites during dealumination is discussed based on the peak intensity changes in the 1H spectra. Ultimately, in situ IR spectra were obtained. Clear correlations were observed between the IR bands and 1H peaks, offering valuable perspectives to refine the interpretation of both IR and NMR spectra. Faujasite ; Zeolite ; Catalysis ; Silanol ; Microporous material ; Chemistry ; Magic angle spinning ; Atomic units ; Molecular sieve ; Inorganic chemistry ; Chemical engineering ; Materials science ; Nuclear magnetic resonance spectroscopy ; Organic chemistry Zeolite Catalysis and Synthesis ; Advanced NMR Techniques and Applications ; Chemical Synthesis and Characterization
Authors: Charbel D. Assaf | Xin Gui | Oleg G. Salnikov | Arne Brahms | Nikita V. Chukanov | Ivan V. Skovpin | Eduard Y. Chekmenev | Rainer Herges | Simon B. Duckett | Igor V. Koptyug | Kai Buckenmaier | Rainer Körber | Markus Plaumann | Alexander A. Auer | Jan‐Bernd Hövener | Andrey N. Pravdivtsev
Source: Communications Chemistry (article, 2024-12-03)
Field: Chemistry — Spectroscopy

Analysis of chemical exchange in iridium N-heterocyclic carbene complexes using heteronuclear parahydrogen-enhanced NMR The signal amplification by reversible exchange process (SABRE) enhances NMR signals by unlocking hidden polarization in parahydrogen through interactions with to-be-hyperpolarized substrate molecules when both are transiently bound to an Ir-based organometallic catalyst. Recent efforts focus on optimizing polarization transfer from parahydrogen-derived hydride ligands to the substrate in SABRE. However, this requires quantitative information on ligand exchange rates, which common NMR techniques struggle to provide. Here, we introduce an experimental spin order transfer sequence, with readout occurring at <sup>15</sup>N nuclei directly interacting with the catalyst. Enhanced <sup>15</sup>N NMR signals overcome sensitivity challenges, encoding substrate dissociation rates. This methodology enables robust data fitting to ligand exchange models, yielding substrate dissociation rate constants with higher precision than classical 1D and 2D <sup>1</sup>H NMR approaches. This refinement improves the accuracy of key activation enthalpy ΔH<sup>‡</sup> and entropy ΔS<sup>‡</sup> estimates. Furthermore, the higher chemical shift dispersion provided by enhanced <sup>15</sup>N NMR reveals the kinetics of substrate dissociation for acetonitrile and metronidazole, previously inaccessible via <sup>1</sup>H NMR due to small chemical shift differences between free and Ir-bound substrates. The presented approach can be successfully applied not only to isotopically enriched substrates but also to compounds with natural abundance of the to-be-hyperpolarized heteronuclei. Spin isomers of hydrogen ; Chemistry ; Heteronuclear molecule ; Iridium ; Dissociation (chemistry) ; Nuclear magnetic resonance spectroscopy ; Catalysis ; Physical chemistry ; Stereochemistry ; Hydrogen ; Organic chemistry Advanced NMR Techniques and Applications ; Atomic and Subatomic Physics Research ; Solid-state spectroscopy and crystallography
Authors: Katarzyna Niesyto | Aleksy Mazur | Dorota Neugebauer
Source: Pharmaceutics (article, 2024-01-30)
Field: Chemistry — Organic Chemistry

Piperacillin/Tazobactam Co-Delivery by Micellar Ionic Conjugate Systems Carrying Pharmaceutical Anions and Encapsulated Drug Previously obtained amphiphilic graft copolymers based on [2-(methacryloyloxy)ethyl]trimethylammonium chloride (TMAMA) ionic liquid were used as the matrices of three types of nanocarriers, i.e., conjugates with ionic piperacillin (PIP) and micelles with tazobactam (TAZ), which represented single systems, and dual systems bearing PIP anions and encapsulated TAZ for co-delivery. The exchange of Cl anions in TMAMA units with PIP ones resulted in a yield of 45.6-72.7 mol.%. The self-assembling properties were confirmed by the critical micelle concentration (CMC), which, after ion exchange, increased significantly (from 0.011-0.020 mg/mL to 0.041-0.073 mg/mL). The amphiphilic properties were beneficial for TAZ encapsulation to reach drug loading contents (DLCs) in the ranges of 37.2-69.5 mol.% and 50.4-80.4 mol.% and to form particles with sizes of 97-319 nm and 24-192 nm in the single and dual systems, respectively. In vitro studies indicated that the ionically conjugated drug (PIP) was released in quantities of 66-81% (7.8-15.0 μg/mL) from single-drug systems and 21-25% (2.6-3.9 μg/mL) from dual-drug systems. The release of encapsulated TAZ was more efficient, achieving 47-98% (7.5-9.0 μg/mL) release from the single systems and 47-69% (9.6-10.4 μg/mL) release from the dual ones. Basic cytotoxicity studies showed non-toxicity of the polymer matrices, while the introduction of the selected drugs induced cytotoxicity against normal human bronchial epithelial cells (BEAS-2B) with the increase in concentration. Nanocarriers ; Chemistry ; Micelle ; Amphiphile ; Drug delivery ; Conjugate ; Ionic bonding ; Nuclear chemistry ; Chromatography ; Polymer ; Organic chemistry ; Copolymer ; Ion ; Aqueous solution Surfactants and Colloidal Systems ; Ionic liquids properties and applications ; Membrane Separation and Gas Transport
Authors: T. Sathish | Jayant Giri | Ibrahim Albaijan
Source: AIP Advances (article, 2024-03-01)
Field: Materials Science — Polymers and Plastics

Investigation into improved characteristics of nanocomposites of kenaf and basalt fibers strengthened with titanium oxide nanoparticles This study explores the thermal and mechanical properties of a composite material formed by blending kenaf and basalt fibers with titanium oxide nanoparticles. To assess its performance under various conditions, we conducted thermogravimetric analysis (TGA) and hardness, sorptivity, and water absorption tests. During experimentation, composite samples were created using kenaf and basalt fibers as the reinforcing matrix and TiO2 nanoparticles as the modifier. Initial findings suggest that the addition of TiO2 nanoparticles enhances the mechanical properties and water resistance of the kenaf and basalt fiber composite. Samples reinforced with TiO2 demonstrated superior hardness and lower water absorption, i.e., KBT2 exhibited a hardness of 92 Hv and a water absorption rate of 6.4%. The value of 0.1% for KBT2 from the sorptivity investigation was promising, indicating its potential applicability in moisture-sensitive environments. In addition, TGA results show that KBT2 exhibited 0%, 2.1%, 4.7%, and 8.3% weight loss, showing improved thermal stability and high resilience to higher temperatures. In conclusion, the development of a novel material combining kenaf and basalt fibers reinforced with TiO2 nanoparticles presents a promising eco-friendly, durable, and lightweight option for engineering applications. Realizing the full potential of this composite material necessitates further characterization and optimization research. Kenaf ; Nanocomposite ; Basalt ; Materials science ; Nanoparticle ; Titanium ; Titanium oxide ; Oxide ; Basalt fiber ; Composite material ; Metallurgy ; Chemical engineering ; Nanotechnology ; Fiber ; Geology ; Geochemistry Natural Fiber Reinforced Composites ; Engineering and Agricultural Innovations ; Nanocomposite Films for Food Packaging
Authors: Sérgio R. S. Veloso | Sara F. Nereu | Carlos O. Amorim | V. S. Amaral | Miguel A. Correa‐Duarte | Elisabete M. S. Castanheira
Source: Materials Today Communications (article, 2024-04-03)
Field: Materials Science — Materials Chemistry

Eco-friendly synthesis of fluorescent cobalt-doped manganese ferrites for thermo-therapeutic applications The synthesis of high-quality nanoparticles for biomedical applications through environmentally friendly methods is a major challenging task. In this work, oxidative precipitation and a novel method, oxidative hydrothermal synthesis, are explored as one-pot eco-friendly synthesis routes to obtain single phase multicore-like and single-core citrate-stabilized cobalt and/or manganese-doped ferrite (CoxMn1-xFe2O4, 0 ≤ x ≤ 1) nanoparticles, respectively. The Co2+/Mn2+ ratio and synthesis method were found to influence the nanoparticles' morphology and structure, with oxidative precipitation producing multicore-like structures and hydrothermal synthesis yielding single-core particles with crystalline sizes in the range of 2 − 10 nm and 4 − 11 nm, respectively. Inductively coupled plasma optical emission spectrometry (ICP-OES) indicated a composition near the expected values. Mixed ferrites displayed improved saturation magnetization up to 60 A.m2/kg, exhibiting superparamagnetism at room temperature. The particles’ stability was evaluated in physiological pH, and the mixed ferrites displayed intrinsic fluorescence emission in the violet-green range with a maximum wavelength near 425 nm. The cobalt and/or manganese-doped ferrites were evaluated for magnetic hyperthermia and photothermia, displaying high heating efficiency for several alternating magnetic field conditions (up to ~2.5 nHm2/kg) compatible with biological applications, and high light-to-heat conversion efficiency (up to ~53%) with near infrared (NIR) laser irradiation at 808 nm. Hereby, the oxidative precipitation and oxidative hydrothermal synthesis are promising eco-friendly methods for the development of crystalline citrate-stabilized cobalt and/or manganese-doped ferrites with multicore-like and single-core spherical morphology, respectively, without requiring additional post-synthesis treatments and with suitable properties for biomedical applications, such as magnetic hyperthermia, photothermia and as prospective fluorescent probes for bio-imaging. Materials science ; Manganese ; Cobalt ; Doping ; Environmentally friendly ; Fluorescence ; Nanotechnology ; Chemical engineering ; Metallurgy ; Optoelectronics Magnetic Properties and Synthesis of Ferrites ; Multiferroics and related materials ; Advancements in Battery Materials
Authors: Sara Panahi | M. Alihosseini | M. Neek-Amal
Source: Journal of Applied Physics (article, 2024-06-03)
Field: Materials Science — Materials Chemistry

Electronic and optical properties of COFs/graphene and COF/hBN heterostructures Covalent organic frameworks (COFs) are a class of intriguing materials with tunable electronic and optical properties. In this work, we investigate the electronic and optical properties of COFs embedded with hBN and graphene. Our results demonstrate that graphene integration enhances the ultraviolet and visible light absorption of C6N6 and B6O6 monolayers, while charge transfer in all COF/graphene heterostructures leads to the formation of a built-in electric field. Furthermore, we show that incorporating hBN into B6O6 and C6N6 heterostructures enables control of their bandgap through an applied electric field, resulting in a semiconductor-to-metal transition under moderate electric field strengths. Additionally, B6O6/hBN exhibits suitable band edge alignment for photocatalytic water splitting. These findings provide valuable insights into the electronic and optical properties of COF heterostructures and their potential applications in electronic and optoelectronic devices. Our study contributes to ongoing efforts in the design and development of novel COF and 2D material heterostructures for future electronic and photonic applications. Graphene ; Heterojunction ; Materials science ; Nanotechnology ; Optoelectronics Boron and Carbon Nanomaterials Research ; Graphene research and applications ; 2D Materials and Applications
Authors: Andri Cahyo Kumoro | Dyah Hesti Wardhani | Tutuk Djoko Kusworo | Mohamad Djaeni | Chin Ping Tan | Misbahudin Alhanif
Source: International Journal of Technology (review, 2024-09-18)
Field: Chemistry — Spectroscopy

Deep Eutectic Solvents and Natural Deep Eutectic Solvents for Extraction and Purification of Proteins from Animal and Botanical Sources - A Review The rising global population has led to an escalating demand for affordable, high-quality proteins intended for human consumption. Different efforts have been made to develop efficient and greener solvents for protein production. Most proteins ar Eutectic system ; Extraction (chemistry) ; Deep eutectic solvent ; Chemistry ; Chromatography ; Materials science ; Organic chemistry Analytical Chemistry and Chromatography ; Molecular spectroscopy and chirality ; Thermodynamic properties of mixtures