jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Shuang Yang | Jia-Bo Huang | Dahua Wang | Ning‐Yi Wang | Yuyu Chen | Xin-Yan Ke | Hao Chen | Shao‐Fei Ni | Yu‐Chen Zhang | Feng Shi
Source: Precision Chemistry (article, 2024-04-23)
Field: Chemistry — Organic Chemistry

Catalytic Asymmetric Diastereodivergent Synthesis of 2-Alkenylindoles Bearing both Axial and Central Chirality The catalytic asymmetric diastereodivergent synthesis of axially chiral 2-alkenylindoles was established via chiral phosphoric acid-catalyzed addition reactions of C3-unsubstituted 2-alkenylindoles with <i>o</i>-hydroxybenzyl alcohols under different reaction conditions. Using this strategy, two series of 2-alkenylindoles bearing both axial and central chirality were synthesized in a diastereodivergent fashion with moderate to high yields and good stereoselectivities (up to 99% yield, 95:5 er, >95:5 dr). Moreover, theoretical calculations were performed on the key transition states leading to different stereoisomers, which provided an in-depth understanding of the origin of the observed stereoselectivity and diastereodivergence of the products under different reaction conditions. More importantly, these 2-alkenylindoles were utilized in asymmetric catalysis as chiral organocatalysts and in medicinal chemistry for evaluation of their cytotoxicity, which demonstrated their potential applications. This study has not only established the catalytic atroposelective synthesis of axially chiral 2-alkenylindoles, but also provided an efficient strategy for catalytic asymmetric diastereodivergent construction of indole-based scaffolds bearing both axial and central chirality. Chirality (physics) ; Catalysis ; Axial chirality ; Bearing (navigation) ; Enantioselective synthesis ; Stereochemistry ; Chemistry ; Physics ; Organic chemistry ; Particle physics Axial and Atropisomeric Chirality Synthesis ; Molecular spectroscopy and chirality ; Asymmetric Synthesis and Catalysis
Authors: Rongjie Yang | Yandong Wang | Zhenbang Zhang | Kang Xu | Linhong Li | Yong Cao | Maohua Li | Jianxiang Zhang | Yue Qin | Boda Zhu | Yingying Guo | Yiwei Zhou | Tao Cai | Cheng‐Te Lin | Kazuhito Nishimura | Xue Chen | Nan Jiang | Jinhong Yu
Source: Materials Horizons (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

Highly oriented BN-based TIMs with high through-plane thermal conductivity and low compression modulus In the pursuit of effective thermal management for electronic devices, it is crucial to develop insulation thermal interface materials (TIMs) that exhibit exceptional through-plane thermal conductivity, low thermal resistance, and minimal compression modulus. Boron nitride (BN), given its outstanding thermal conduction and insulation properties, has garnered significant attention as a potential material for this purpose. However, previously reported BN-based composites have consistently demonstrated through-plane thermal conductivity below 10 W m<sup>-1</sup> K<sup>-1</sup> and high compression modulus, whilst also presenting challenges in terms of mass production. In this study, low molecular weight polydimethylsiloxane (PDMS) and large-size BN were utilized as the foundational materials. Utilizing a rolling-curing integrated apparatus, we successfully accomplished the continuous preparation of large-sized, high-adhesion BN films. Subsequent implementation of stacking, cold pressing, and vertical cutting techniques enabled the attainment of a remarkable BN-based TIM, characterized by an unprecedented through-plane thermal conductivity of up to 12.11 W m<sup>-1</sup> K<sup>-1</sup>, remarkably low compression modulus (55 kPa), and total effective thermal resistance (0.16 °C in<sup>2</sup> W<sup>-1</sup>, 50 Psi). During the TIMs performance evaluation, our TIMs demonstrated superior heat dissipation capabilities compared with commercial TIMs. At a heating power density of 40 W cm<sup>-2</sup>, the steady-state temperature of the ceramic heating element was found to be 7 °C lower than that of the commercial TIMs. This pioneering feat not only contributes valuable technical insights for the development of high-performance insulating TIMs but also establishes a solid foundation for widespread implementation in thermal management applications across a range of electronic devices. Thermal conductivity ; Materials science ; Composite material ; Thermal resistance ; Thermal ; Modulus ; Thermal grease ; Plane (geometry) ; Compression (physics) ; Thermal insulation ; Thermodynamics ; Geometry ; Physics Thermal properties of materials ; Advanced ceramic materials synthesis ; Aerogels and thermal insulation
Authors: Jin Yao | Wei‐Lun Hsu | Yao Liang | Rong Lin | Mu Ku Chen | Din Ping Tsai
Source: Science Advances (article, 2024-04-17)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Nonlocal metasurface for dark-field edge emission Nonlocal effects originating from interactions between neighboring meta-atoms introduce additional degrees of freedom for peculiar characteristics of metadevices, such as enhancement, selectivity, and spatial modulation. However, they are generally difficult to manipulate because of the collective responses of multiple meta-atoms. Here, we experimentally demonstrate the nonlocal metasurface to realize the spatial modulation of dark-field emission. Plasmonic asymmetric split rings (ASRs) are designed to simultaneously excite local dipole resonance and nonlocal quasi-bound states in the continuum and spatially extended modes. With one type of unit, nonlocal effects are tailored by varying array periods. ASRs at the metasurface's edge lack sufficient interactions, resulting in stronger dark-field scattering and thus edge emission properties of the metasurface. Pixel-level spatial control is demonstrated by simply erasing some units, providing more flexibility than conventional local metasurfaces. This work paves the way for manipulating nonlocal effects and facilitates applications in optical trapping and sorting at the nanoscale. Physics ; Dipole ; Plasmon ; Enhanced Data Rates for GSM Evolution ; Modulation (music) ; Scattering ; Field (mathematics) ; Optics ; Computer science ; Telecommunications ; Quantum mechanics ; Acoustics Metamaterials and Metasurfaces Applications ; Plasmonic and Surface Plasmon Research ; Orbital Angular Momentum in Optics
Authors: Devashish Dubey | Anooshe Sadat Mirhakimi | M.A. Elbestawi
Source: Journal of Manufacturing and Materials Processing (review, 2024-02-14)
Field: Materials Science — Materials Chemistry

Negative Thermal Expansion Metamaterials: A Review of Design, Fabrication, and Applications Most materials conventionally found in nature expand with an increase in temperature. In actual systems and assemblies like precision instruments, this can cause thermal distortions which can be difficult to handle. Materials with a tendency to shrink with an increase in temperature can be used alongside conventional materials to restrict the overall dimensional change of structures. Such structures, also called negative-thermal-expansion materials, could be crucial in applications like electronics, biomedicine, aerospace components, etc., which undergo high changes in temperature. This can be achieved using mechanically engineered materials, also called negative thermal expansion (NTE) mechanical metamaterials. Mechanical metamaterials are mechanically architected materials with novel properties that are rare in naturally occurring materials. NTE metamaterials utilize their artificially engineered architecture to attain the rare property of negative thermal expansion. The emergence of additive manufacturing has enabled the feasible production of their intricate architectures. Industrial processes such as laser powder bed fusion and direct energy deposition, both utilized in metal additive manufacturing, have proven successful in creating complex structures like lattice formations and multimaterial components in the industrial sector, rendering them suitable for manufacturing NTE structures. Nevertheless, this review examines a range of fabrication methods, encompassing both additive and traditional techniques, and explores the diverse materials used in the process. Despite NTE metamaterials being a prominent field of research, a comprehensive review of these architected materials is missing in the literature. This article aims to bridge this gap by providing a state-of-the-art review of these metamaterials, encompassing their design, fabrication, and cutting-edge applications. Metamaterial ; Negative thermal expansion ; Fabrication ; Materials science ; Nanotechnology ; Aerospace ; Thermal expansion ; Structural material ; Mechanical engineering ; Engineering physics ; Computer science ; Optoelectronics ; Engineering ; Aerospace engineering ; Composite material Thermal Expansion and Ionic Conductivity ; Thermodynamic and Structural Properties of Metals and Alloys ; Cellular and Composite Structures
Authors: Jun Zhi Tan | Maaso Ortega | Sophia A. Miller | Cole W. Hullfish | Hojoon Kim | Sung Min Kim | Wenda Hu | Jian Zhi Hu | Johannes A. Lercher | Bruce E. Koel | Michele L. Sarazen
Source: ACS Catalysis (article, 2024-04-30)
Field: Chemistry — Inorganic Chemistry

Catalytic Consequences of Hierarchical Pore Architectures within MFI and FAU Zeolites for Polyethylene Conversion The benefits of hierarchical zeolites for the conversion of bulky molecules like polymeric waste have been reported in the literature; however, the impact of mesopore sizes and connectivities on rates, product selectivities, and catalyst deactivation in the context of plastic upcycling has not been systematically probed. Here, we synthesized a suite of hierarchical MFI and FAU zeolites via desilication under varying conditions for metal-free polyethylene conversion reactions under batch and flow conditions (473–523 K). Polyethylene (solid) conversion rates (normalized by Bro̷nsted acid site density) were higher on hierarchical than parent microporous MFI regardless of mesopore connectivities, i.e., open or constricted, suggesting that the incorporation of mesopores facilitates diffusion of intermediate products to access medium-pore protons for successive scission events. Furthermore, higher branched:linear gaseous product ratios were produced on hierarchical than parent MFI, since mesopores allow for egress of bulkier molecules without undergoing further secondary events, e.g., isomerization back to linear alkanes/alkenes or beta scission. Solid conversion rates on hierarchical FAU synthesized via desilication with cetyltrimethylammonium bromide (CTABr), however, were not higher than parent FAU, likely because the presence of CTABr facilitates recrystallization of leached species to form composites (hierarchical FAU and ordered mesoporous materials) with more isolated mesopores. The stagnation in rates, despite increased mesopore volumes (>0.22 cm3 g–1), highlights the importance of confinement effects provided by micropores for cleaving C–C bonds at modest reaction conditions. In situ 1H MAS NMR performed on polyethylene with MFI zeolite show that PE isomerizes (and potentially deconstructs) at temperatures near 450 K, highlighting the role of Bro̷nsted acid sites in activating C–C bonds under mild reaction conditions. Catalyst recyclability studies showed that all catalysts undergo deactivation during plastic upcycling reactions, but to varying extents. Overall, hierarchical materials have better catalyst stability than parent materials, although the differences in stability between hierarchical and parent FAU are smaller than those for MFI. Taken together, these findings demonstrate how rates, selectivities, and catalyst deactivation from plastic upcycling reactions can be controlled via fine-tuning the identity and connectivity of mesopores. Mesoporous material ; Microporous material ; Catalysis ; Zeolite ; Chemical engineering ; Materials science ; Polyethylene ; Chemistry ; Organic chemistry Zeolite Catalysis and Synthesis ; Polymer crystallization and properties ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Yongqiang Zhang | Shurong Ding | Jingkun Yu | Laizhi Sui | Haoqiang Song | Yongsheng Hu | Geoffrey I. N. Waterhouse | Zhiyong Tang | Siyu Lu
Source: Matter (article, 2024-07-02)
Field: Materials Science — Materials Chemistry

Unveiling the photoluminescence mechanisms of carbon dots through tunable near-infrared dual-wavelength lasing Photoluminescence ; Lasing threshold ; Optoelectronics ; Infrared ; Materials science ; Wavelength ; Dual (grammatical number) ; Carbon fibers ; Optics ; Nanotechnology ; Physics ; Art Carbon and Quantum Dots Applications ; Luminescence and Fluorescent Materials ; Photonic Crystals and Applications
Authors: Qinxuan Cao | Jianning Feng | Kin Ting Chang | Wenfei Liang | Haipeng Lu
Source: Advanced Materials (review, 2024-09-28)
Field: Materials Science — Materials Chemistry

Emerging Opportunities of Colloidal Quantum Dots for Photocatalytic Organic Transformations Colloidal quantum dots (QDs) have emerged as a versatile photocatalyst for a wide range of photocatalytic transformations owing to its high absorption coefficient, large surface-to-volume ratio, high stability, and efficient charge and energy transfer dynamics. The past decades have witnessed a rapid development of QDs for artificial photocatalysis. In this review, the unique characteristics of QDs are focused on, including quantum size effect, compositional and structural diversity, tunable surface chemistry, and photophysics, that can be utilized for photocatalytic transformations. The recent advancements in photocatalytic organic transformations enabled by QDs photocatalysts are summarized. The unique opportunities of QDs are highlighted to tackle organic reactions that are previously unattainable with small molecule photocatalysts. Lastly, an outlook is provided for future directions in this field. Photocatalysis ; Quantum dot ; Materials science ; Nanotechnology ; Colloid ; Catalysis ; Chemical engineering ; Chemistry ; Organic chemistry Quantum Dots Synthesis And Properties ; Advanced Photocatalysis Techniques ; Nanocluster Synthesis and Applications
Authors: Vijay N. Wakchaure | William DeSnoo | Croix J. Laconsay | Markus Leutzsch | Nobuya Tsuji | Dean J. Tantillo | Benjamin List
Source: Nature (article, 2024-01-10)
Field: Chemistry — Organic Chemistry

Catalytic asymmetric cationic shifts of aliphatic hydrocarbons Asymmetric catalysis is an advanced area of chemical synthesis, but the handling of abundantly available, purely aliphatic hydrocarbons has proven to be challenging. Typically, heteroatoms or aromatic substructures are required in the substrates and reagents to facilitate an efficient interaction with the chiral catalyst. Confined acids have recently been introduced as tools for homogenous asymmetric catalysis, specifically to enable the processing of small unbiased substrates<sup>1</sup>. However, asymmetric reactions in which both substrate and product are purely aliphatic hydrocarbons have not previously been catalysed by such super strong and confined acids. We describe here an imidodiphosphorimidate-catalysed asymmetric Wagner-Meerwein shift of aliphatic alkenyl cycloalkanes to cycloalkenes with excellent regio- and enantioselectivity. Despite their long history and high relevance for chemical synthesis and biosynthesis, Wagner-Meerwein reactions utilizing purely aliphatic hydrocarbons, such as those originally reported by Wagner and Meerwein, had previously eluded asymmetric catalysis. Catalysis ; Chemistry ; Cationic polymerization ; Enantioselective synthesis ; Heteroatom ; Substrate (aquarium) ; Organic chemistry ; Reagent ; Organocatalysis ; Combinatorial chemistry ; Ring (chemistry) Asymmetric Synthesis and Catalysis ; Asymmetric Hydrogenation and Catalysis ; Axial and Atropisomeric Chirality Synthesis
Authors: Sylwia Głowniak | Barbara Szczęśniak | J. Choma | Mietek Jaroniec
Source: Molecules (article, 2024-06-06)
Field: Chemistry — Inorganic Chemistry

Mechanochemical Synthesis of MOF-303 and Its CO2 Adsorption at Ambient Conditions Metal-organic structures have great potential for practical applications in many areas. However, their widespread use is often hindered by time-consuming and expensive synthesis procedures that often involve hazardous solvents and, therefore, generate wastes that need to be remediated and/or recycled. The development of cleaner, safer, and more sustainable synthesis methods is extremely important and is needed in the context of green chemistry. In this work, a facile mechanochemical method involving water-assisted ball milling was used for the synthesis of MOF-303. The obtained MOF-303 exhibited a high specific surface area of 1180 m<sup>2</sup>/g and showed an excellent CO<sub>2</sub> adsorption capacity of 9.5 mmol/g at 0 °C and under 1 bar. Adsorption ; Hazardous waste ; Metal-organic framework ; SAFER ; Context (archaeology) ; Materials science ; Chemical engineering ; Ball mill ; Process engineering ; Green chemistry ; Environmental science ; Nanotechnology ; Waste management ; Chemistry ; Organic chemistry ; Computer science ; Catalysis ; Engineering ; Metallurgy ; Geology ; Reaction mechanism Metal-Organic Frameworks: Synthesis and Applications ; Carbon dioxide utilization in catalysis ; Covalent Organic Framework Applications
Authors: Jiawei Lin | Jianmin Zhou | Liang Li | Ibrahim Tahir | Songgu Wu | Pancě Naumov | Junbo Gong
Source: Nature Communications (article, 2024-04-29)
Field: Materials Science — Materials Chemistry

Highly efficient in crystallo energy transduction of light to work Various mechanical effects have been reported with molecular materials, yet organic crystals capable of multiple dynamic effects are rare, and at present, their performance is worse than some of the common actuators. Here, we report a confluence of different mechanical effects across three polymorphs of an organic crystal that can efficiently convert light into work. Upon photodimerization, acicular crystals of polymorph I display output work densities of about 0.06-3.94 kJ m<sup>-3</sup>, comparable to ceramic piezoelectric actuators. Prismatic crystals of the same form exhibit very high work densities of about 1.5-28.5 kJ m<sup>-3</sup>, values that are comparable to thermal actuators. Moreover, while crystals of polymorph II roll under the same conditions, crystals of polymorph III are not photochemically reactive; however, they are mechanically flexible. The results demonstrate that multiple and possibly combined mechanical effects can be anticipated even for a simple organic crystal. Acicular ; Work (physics) ; Piezoelectricity ; Materials science ; Crystal (programming language) ; Mechanical energy ; Actuator ; Crystal structure ; Thermal ; Crystallography ; Chemical physics ; Chemistry ; Composite material ; Thermodynamics ; Physics Luminescence and Fluorescent Materials ; Advanced Sensor and Energy Harvesting Materials ; Silicone and Siloxane Chemistry
Authors: Jessica Patel | Razia Khan Sharme | Manuel A. Quijada | Mukti M. Rana
Source: Nanomaterials (review, 2024-12-14)
Field: Materials Science — Materials Chemistry

A Review of Transparent Conducting Films (TCFs): Prospective ITO and AZO Deposition Methods and Applications This study offers a comprehensive summary of the current states as well as potential future directions of transparent conducting oxides (TCOs), particularly tin-doped indium oxide (ITO), the most readily accessible TCO on the market. Solar cells, flat panel displays (FPDs), liquid crystal displays (LCDs), antireflection (AR) coatings for airbus windows, photovoltaic and optoelectronic devices, transparent p-n junction diodes, etc. are a few of the best uses for this material. Other conductive metals that show a lot of promise as substitutes for traditional conductive materials include copper, zinc oxide, aluminum, silver, gold, and tin. These metals are also utilized in AR coatings. The optimal deposition techniques for creating ITO films under the current conditions have been determined to be DC (direct current) and RF (radio frequency) MS (magnetron sputtering) deposition, both with and without the introduction of Ar gas. When producing most types of AR coatings, it is necessary to obtain thicknesses of at least 100 nm and minimum resistivities on the order of 10<sup>-4</sup> Ω cm. For AR coatings, issues related to less-conductive materials than ITO have been considered. Materials science ; Transparent conducting film ; Indium tin oxide ; Optoelectronics ; Electrical conductor ; Doping ; Sputtering ; Deposition (geology) ; Diode ; Liquid-crystal display ; Sputter deposition ; Flat panel display ; Tin ; Direct current ; Photovoltaics ; Thin film ; Nanotechnology ; Photovoltaic system ; Metallurgy ; Composite material ; Voltage ; Electrical engineering ZnO doping and properties ; Nanomaterials and Printing Technologies ; Thin-Film Transistor Technologies
Authors: Yulong Liu | Ting-yu Zhu | Qin Wang | Zi-jie Huang | De‐xiang Sun | Jing‐hui Yang | Xiaodong Qi | Yong Wang
Source: Nano-Micro Letters (article, 2024-12-26)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Hierarchically Porous Polypyrrole Foams Contained Ordered Polypyrrole Nanowire Arrays for Multifunctional Electromagnetic Interference Shielding and Dynamic Infrared Stealth As modern communication and detection technologies advance at a swift pace, multifunctional electromagnetic interference (EMI) shielding materials with active/positive infrared stealth, hydrophobicity, and electric-thermal conversion ability have received extensive attention. Meeting the aforesaid requirements simultaneously remains a huge challenge. In this research, the melamine foam (MF)/polypyrrole (PPy) nanowire arrays (MF@PPy) were fabricated via one-step electrochemical polymerization. The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays. Due to the upwardly grown PPy nanowire arrays, the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00° and outstanding stability under various harsh environments. Meanwhile, the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays. Furthermore, taking advantage of the high conductivity (128.2 S m<sup>-1</sup>), the MF@PPy foam exhibited rapid Joule heating under 3 V, resulting in dynamic infrared stealth and thermal camouflage effects. More importantly, the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm<sup>2</sup> g<sup>-1</sup>. Strong EMI shielding was put down to the hierarchically porous PPy structure, which offered outstanding impedance matching, conduction loss, and multiple attenuations. This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays, showing great applications in both military and civilian fields. Polypyrrole ; Materials science ; Electromagnetic shielding ; Nanowire ; Composite material ; EMI ; Porosity ; Conductive polymer ; Electromagnetic interference ; Nanotechnology ; Polymer ; Polymerization ; Electrical engineering Electromagnetic wave absorption materials ; Advanced Antenna and Metasurface Technologies ; Dielectric materials and actuators