bluuebunny/crossref_metadata_2025_split huggingface dataset:
The hydroboration-oxidation mechanism: An updated look.
Authors: Rzepa Henry 
Published: September 2023

One thing almost always leads to another in chemistry. In the last post, I described how an antiperiplanar migration could compete with an antiperiplanar elimination. This leads to the hydroboration-oxidation mechanism, the discovery of which resulted in Herbert C. Brown (at least in part) being awarded the Nobel prize in 1979. This reaction represents a fairly steep learning curve for new students of organic chemistry.
Mechanism of the reduction of a carboxylic acid by borane: revisited and revised.
Authors: Rzepa Henry 
Published: September 2023

I asked a while back whether blogs could be considered a serious form of scholarly scientific communication (and so has Peter Murray-Rust more recently). A case for doing so might be my post of about a year ago, addressing why borane reduces a carboxylic acid, but not its ester, where I suggested a possible mechanism.
The colour of purple
Authors: Rzepa Henry 
Published: September 2023

One of my chemical heroes is William Perkin, who in 1856 famously (and accidentally) made the dye mauveine as an 18 year old whilst a student of August von Hofmann, the founder of the Royal College of Chemistry (at what is now Imperial College London). Perkin went on to found the British synthetic dyestuffs and perfumeries industries.
Can a cyclobutadiene and carbon dioxide co-exist in a calixarene cavity?
Authors: Rzepa Henry 
Published: September 2023

On 8th August this year, I posted on a fascinating article that had just appeared in Science[cite]10.1126/science.1188002[/cite] in which the crystal structure was reported of two small molecules, 1,3-dimethyl cyclobutadiene and carbon dioxide, entrapped together inside a calixarene cavity.
More is more: the dyotropic rearrangement of 1,2-dibromoethane.
Authors: Rzepa Henry 
Published: September 2023

In the previous post, I discussed what we could learn from ethane by forcing it into a pericyclic dyotropic rearrangement. We saw how it voraciously scavenged two electrons from the C-C bond to achieve this. What if we give it more electrons? Thus 1,2-dibromoethane undergoing the same reaction. Dyotropic rearrangement of 1,2-dibromoethane.
Metallic carbon nanotori
Authors: Rzepa Henry 
Published: September 2023

The interface between physics, chemistry (and materials science) can be a fascinating one. Here I show a carbon nanotorus, devised by physicists[cite]10.1103/PhysRevLett.88.217206[/cite] a few years ago. It is a theoretical species, and was predicted to have a
<em>
colossal paramagnetic moment
</em>
. Carbon nanotorus.
Spotting the unexpected. The trifluoromeric effect in the hydration of the carbonyl group.
Authors: Rzepa Henry 
Published: September 2023

The equilibrium for the hydration of a ketone to form a gem-diol hydrate is known to be highly sensitive to substituents. Consider the two equilibria: For propanone, it lies almost entirely on the left, whereas for the hexafluoro derivative it is almost entirely on the right. The standard answer to this is that electron-withdrawing substituents destabilize the carbonyl compound more than the hydrate.
The problems of the unity of the Russian people and the issues of its solidarity in modern conditions
Authors: Tarkhanova Aleksandra Vladimirovna , Avdeev Dmitrii Aleksandrovich 
Published: September 2023

In the conditions of global turbulence and global challenges, the basis for the formation of a new, patriotic and law-educated society is to take the necessary measures to raise the level of legal consciousness, reduce absenteeism and legal nihilism, which will allow Russian citizens to soberly assess certain foreign challenges. The solution of this issue primarily involves its consideration from three sides: from the state, the adult population and youth. The efforts of the state in the field of increasing the level of unity and patriotism of the Russian people will generally raise the level of legal literacy of both adults and young people. The article examines the approaches of different authors to the understanding of the terms "patriotism", "solidarity" and "unity of the people". The normative legal acts, national development strategies and federal programs aimed at increasing the level of patriotism, strengthening the unity of the Russian nation and the ethno-cultural development of the peoples of Russia are considered. Through the analysis of historical events and the attitude of the population to the National Unity Day in Russia, conclusions are drawn about the possible causes of the low level of patriotism among the Russian population, and on the basis of these conclusions, a number of measures are proposed to strengthen the unity of the people and its solidarity in modern conditions.
H‐BN‐Encapsulated Uncooled Infrared Photodetectors Based on Tantalum Nickel Selenide
Authors: Zhang Shi , Han Li , Xiao Kening , Zhang Libo , Shi Chaofan , Xu Leijun , Deng Ke , Zou Yuanchen , Jiang Mengjie , Lv Xuyang , Zhu Yulin , Li Qing , Liu Changlong , Tang Weiwei , Li Guanhai , Ding Songyuan , Chen Xiaoshuang , Lu Wei 
Published: September 2023

AbstractUncooled broadband spectrum detection, spanning from visible to mid‐wave‐infrared regions, offers immense potential for applications in environmental monitoring, optical telecommunications, and radar systems. While leveraging proven technologies, conventional mid‐wave‐infrared photodetectors are encumbered by high dark currents and the necessity for cryogenic cooling. Correspondingly, innovative low‐dimensional materials like black phosphorus manifest weak photoresponse and instability. Here, tantalum nickel selenide (Ta2NiSe5) infrared photodetectors with an operational wavelength range from 520 nm to 4.6 µm, utilizing a hexagonal boron nitride (h‐BN) encapsulation technique are introduced. The h‐BN encapsulated metal‐Ta2NiSe5‐metal photodetector demonstrates a responsivity of 0.86 A W−1, a noise equivalent power of 1.8 × 10−11 W Hz−1/2, and a peak detectivity of 8.75 × 108 cm Hz1/2 W−1 at 4.6 µm under ambient conditions. Multifaceted mechanisms of photocurrent generation in the novel device prototype subject are scrutinized to varying wavelengths of radiation, by characterizing the temporal‐, bias‐, power‐, and temperature‐dependent photoresponse. Moreover, the photopolarization dependence is delved and concealed‐target imaging is demonstrated, which exhibits polarization angle sensitivity and high‐fidelity imaging across the visible, short‐wave, and mid‐wave‐infrared bands. The observations, which reveal versatile detection modalities, propose Ta2NiSe5 as a promising low‐dimensional material for advanced applications in nano‐optoelectronic device.
Ultra‐High‐Energy Density in Layered Sodium‐Ion Battery Cathodes through Balancing Lattice‐Oxygen Activity and Reversibility
Authors: Lu Hangyu , Chu Shiyong , Tian Jiaming , Wang Qi , Sheng Chuanchao , Cheng Chen , Liu Rixin , D'Angelo Anita M. , Pang Wei Kong , Zhang Liang , Zhou Haoshen , Guo Shaohua 
Published: September 2023

AbstractLattice‐oxygen redox in layered metal oxide cathodes offers a promising way to exploit high‐energy density sodium‐ion batteries. However, oxidation and reduction of lattice‐oxygen are always asymmetric, showing poor reversibility upon charging and discharging due to the activated oxygen loss and subsequent structural rearrangement. Here, a layered Na0.7[Li0.2Mn0.7Co0.1]O2 (NLMCO) is developed by balancing lattice‐oxygen activity and reversibility, which can deliver a record energy density of 729.7 Wh kg−1, further exceeding the state‐of‐the‐art Na0.75[Li0.25Mn0.75]O2 (NLMO, 638.4 Wh kg−1). In light of electron paramagnetic resonance spectroscopy, in situ differential electrochemical mass spectroscopy, and electrochemical testing results, the highly activated lattice‐oxygen is effectively stabilized in NLMCO without oxygen molecule release while obvious oxygen release is detected in the highly activated NLMO. Benefiting from the enhanced transition metal‐oxygen covalency and reduced band energy gap, the NLMCO electrode demonstrates simultaneously high lattice‐oxygen activity and reversibility, thus resulting in excellent rate and cycling performance, as well as ultra‐high energy density. The findings highlight the critical association of energy density and lattice‐oxygen redox reversibility, which will inspire more interest in anionic redox‐based high‐energy batteries.
Patterning of a High Surface Area Liquid Metal‐Carbon Composite Film Using Laser Processing
Authors: Frey Ethan J. , Im Sooik , Bachmann Adam L. , Genzer Jan , Dickey Michael D. 
Published: September 2023

AbstractLiquid metal is a compelling material for making soft and stretchable devices due to its high electrical conductivity and extreme stretchability. One way to pattern liquid metal is to nebulize it into small droplets, spray it onto a surface as a film, and then use a laser to “sinter” it into circuit patterns. Here, it is shown that including poly(amic acid) in the spray‐deposited film has multiple benefits: it (1) allows the unsintered regions to be removed easily, (2) lowers the power required for sintering, (3) converts to carbon upon exposure to create a carbon‐metal composite, and (4) increases the surface area of the film by 2632% compared to bulk EGaIn. The conductive liquid metal‐carbon circuits can also be transferred to a soft substrate to produce stretchable conductors. The circuits slightly increase in conductivity up to ≈30% strain and then decrease such that by 100% strain, the resistance is only ≈1.02 times its initial resistance. Lastly, the film is highly reactive with water molecules in the air, increasing in resistance over time in humid conditions. The high reactivity and surface area of the film indicate potential applications in batteries, catalysts, and capacitors. Meanwhile, the facile patterning indicates potential applications in soft circuits.
Assembly of Multisurfaced Van der Waals Layered Compound GaSe via Thermal Oxidation
Authors: Zheng Sikang , Li Jingwei , Zhang Daliang , Zhou Zizhen , Liu Jie , Tao Yanyan , Fang Xuan , Yang Xiaolong , Han Guang , Lu Xu , Wang Guoyu , Zhang Bin , Wang Dengkui , Zhou Xiaoyuan 
Published: September 2023

AbstractThe investigation of the oxidation behavior of van der Waals chalcogenides holds significant importance in terms of preventing and controlling oxidation, utilizing surface oxidation structures to regulate properties, and advancing applications. Here, taking GaSe as a candidate, its thermal oxidation and surface structure evolution are intensively studied. Through systematic microscopic analyses, oxidized structures at multi‐scale (from atomic scale to millimeters) are resolved, and various assembly heterogeneous surfaces including Ga2Se3/Ga2O3 and Ga2O3 multilayers are uncovered at different oxidation temperatures. The temperature‐dependent oxidation behavior and surface structure evolution of the GaSe are revealed, and the oxidation mechanisms in the entire temperature range are also disclosed. Finally, the photoluminescence regulation of the GaSe is initially explored via thermal oxidation, demonstrating great potential for surface oxidation engineering. This study is not only of great importance for the deep understanding and utilization of GaSe oxidation, but also beneficial for materials/device design and development of relative systems.
Hydroxyapatite‐Coated Small Intestinal Submucosa Membranes Enhanced Periodontal Tissue Regeneration through Immunomodulation and Osteogenesis via BMP‐2/Smad Signaling Pathway
Authors: Cheng Guoping , Guo Shujuan , Li Maoxue , Xiao Shimeng , Jiang Bo , Ding Yi 
Published: September 2023

AbstractPeriodontitis, a chronic infection causing periodontal tissue loss, may be effectively addressed with in situ tissue engineering. Small intestinal submucosa (SIS) offers exceptional biocompatibility and biodegradability but lacks sufficient osteoconductive and osteoinductive properties. This study develops and characterizes SIS coated with hydroxyapatite (SIS‐HA) and gelatin methacrylate hydroxyapatite (SIS‐Gel‐HA) using biomineralization and chemical crosslinking. The impact on periodontal tissue regeneration is assessed by evaluating macrophage immune response and osteogenic differentiation potential of periodontal ligament stem cells (PDLSCs) in vitro and rat periodontal defects in vivo. The jejunum segment, with the highest collagen type I content, is optimal for SIS preparation. SIS retains collagen fiber structure and bioactive factors. Calcium content is 2.21% in SIS‐HA and 2.45% in SIS‐Gel‐HA, with no significant differences in hydrophilicity, physicochemical properties, protein composition, or biocompatibility among SIS, SIS‐HA, SIS‐Gel, and SIS‐Gel‐HA. SIS is found to upregulate M2 marker expression, both SIS‐HA and SIS‐Gel‐HA enhance the osteogenic differentiation of PDLSCs through the BMP‐2/Smad signaling pathway, and SIS‐HA demonstrates superior in vitro osteogenic activity. In vivo, SIS‐HA and SIS‐Gel‐HA yield denser, more mature bones with the highest BMP‐2 and Smad expression. SIS‐HA and SIS‐Gel‐HA demonstrate enhanced immunity–osteogenesis coupling, representing a promising periodontal tissue regeneration approach.
Hypoxic Microenvironment Reconstruction with Synergistic Biofunctional Ions Promotes Diabetic Wound Healing
Authors: Chen Xiaochen , Zhang Liyan , Chai Wenwen , Tian Pengfei , Kim Jua , Ding Jingxin , Zhang Hao , Liu Chunyu , Wang Deping , Cui Xu , Pan Haobo 
Published: September 2023

AbstractChronic hypoxia and ischemia make diabetic wounds non‐healing. Cellular functions of diabetic chronic wounds are inhibited under a pathological environment. Therefore, this work develops a composite hydrogel system to promote diabetic wound healing. The composite hydrogel system consists of ε‐poly‐lysine (EPL), calcium peroxide (CP), and borosilicate glass (BG). The hydrogel supplies continuous dissolved oxygen molecules to the wound that can penetrate the skin tissue to restore normal cellular function and promote vascular regeneration. Biofunctional ions released from BGs can recruit more macrophages through neovascularization and modulate macrophage phenotypic transformation. Combining oxygen‐mediated vascular regeneration and ion‐mediated inflammatory regulation significantly accelerated diabetic wound healing. These findings indicate that this composite hydrogel system holds promise as a novel tissue engineering material.
Polysulfides in Magnesium‐Sulfur Batteries
Authors: Luo Tongtong , Wang Yang , Elander Brooke , Goldstein Michael , Mu Yu , Wilkes James , Fahrenbruch Mikayla , Lee Justin , Li Tevin , Bao Junwei Lucas , Mohanty Udayan , Wang Dunwei 
Published: September 2023

AbstractMg‐S batteries hold great promise as a potential alternative to Li‐based technologies. Their further development hinges on solving a few key challenges, including the lower capacity and poorer cycling performance when compared to Li counterparts. At the heart of the issues is the lack of knowledge on polysulfide chemical behaviors in the Mg‐S battery environment. In this Review, a comprehensive overview of the current understanding of polysulfide behaviors in Mg‐S batteries is provided. First, a systematic summary of experimental and computational techniques for polysulfide characterization is provided. Next, conversion pathways for Mg polysulfide species within the battery environment are discussed, highlighting the important role of polysulfide solubility in determining reaction kinetics and overall battery performance. The focus then shifts to the negative effects of polysulfide shuttling on Mg‐S batteries. The authors outline various strategies for achieving an optimal balance between polysulfide solubility and shuttling, including the use of electrolyte additives, polysulfide‐trapping materials, and dual‐functional catalysts. Based on the current understanding, the directions for further advancing knowledge of Mg polysulfide chemistry are identified, emphasizing the integration of experiment with computation as a powerful approach to accelerate the development of Mg‐S battery technology.
Shape‐Configurable MXene‐Based Thermoacoustic Loudspeakers with Tunable Sound Directivity
Authors: Kim Jinyoung , Jung Geonyoung , Jung Seokhee , Bae Myung Hwan , Yeom Jeonghee , Park Jonghwa , Lee Youngoh , Kim Young‐Ryul , Kang Dong‐hee , Oh Joo Hwan , Park Seungyoung , An Ki‐Seok , Ko Hyunhyub 
Published: September 2023

AbstractFilm‐type shape‐configurable speakers with tunable sound directivity are in high demand for wearable electronics. Flexible, thin thermoacoustic (TA) loudspeakers—which are free from bulky vibrating diaphragms—show promise in this regard. However, configuring thin TA loudspeakers into arbitrary shapes is challenging because of their low sound pressure level (SPL) under mechanical deformations and low conformability to other surfaces. By carefully controlling the heat capacity per unit area and thermal effusivity of an MXene conductor and substrates, respectively, it fabricates an ultrathin MXene‐based TA loudspeaker exhibiting high SPL output (74.5 dB at 15 kHz) and stable sound performance for 14 days. Loudspeakers with the parylene substrate, whose thickness is less than the thermal penetration depth, generated bidirectional and deformation‐independent sound in bent, twisted, cylindrical, and stretched‐kirigami configurations. Furthermore, it constructs parabolic and spherical versions of ultrathin, large‐area (20 cm × 20 cm) MXene‐based TA loudspeakers, which display sound‐focusing and 3D omnidirectional‐sound‐generating attributes, respectively.
Technology and Integration Roadmap for Optoelectronic Memristor
Authors: Wang Jinyong , Ilyas Nasir , Ren Yujing , Ji Yun , Li Sifan , Li Changcun , Liu Fucai , Gu Deen , Ang Kah‐Wee 
Published: September 2023

AbstractOptoelectronic memristors (OMs) have emerged as a promising optoelectronic Neuromorphic computing paradigm, opening up new opportunities for neurosynaptic devices and optoelectronic systems. These OMs possess a range of desirable features including minimal crosstalk, high bandwidth, low power consumption, zero latency, and the ability to replicate crucial neurological functions such as vision and optical memory. By incorporating large‐scale parallel synaptic structures, OMs are anticipated to greatly enhance high‐performance and low‐power in‐memory computing, effectively overcoming the limitations of the von Neumann bottleneck. However, progress in this field necessitates a comprehensive understanding of suitable structures and techniques for integrating low‐dimensional materials into optoelectronic integrated circuit platforms. This review aims to offer a comprehensive overview of the fundamental performance, mechanisms, design of structures, applications, and integration roadmap of optoelectronic synaptic memristors. By establishing connections between materials, multilayer optoelectronic memristor units, and monolithic optoelectronic integrated circuits, this review seeks to provide insights into emerging technologies and future prospects that are expected to drive innovation and widespread adoption in the near future.
All‐Screen‐Coatable Photo‐Thermoelectric Imagers for Physical and Thermal Durability Enhancement
Authors: Li Kou , Matsuzaki Yuto , Takahara Sota , Sakai Daiki , Aoshima Yuto , Takahashi Norika , Yamamoto Minami , Kawano Yukio 
Published: September 2023

AbstractCarbon nanotube (CNT) film photo‐thermoelectric (PTE) imagers are suitable for non‐destructive inspection techniques owing to their functionalities. Simultaneously, their practical application remains a crucial bottleneck due to low yield handling in the device fabrication (e.g., disconnections between photo absorbent channels and readout electrodes). However, studies clarifying the above malfunction mechanism and associated dominant factors in device handling, such as specific fabrication or material selection steps, still need to be completed. To address this issue, this work introduces all‐screen‐coatable fabrication techniques for CNT film PTE imagers to enhance their physical and thermal durabilities. First, this work determined that the transfer of CNT films on supporting substrates dominantly governs the mechanical robustness of the channels and that thermal curing in the subsequent fabrication process is an essential factor in the yields of channel‐electrode connections. The proposed approach ensures a transfer‐free direct coating of the CNT film on diverse substrates and is sufficiently durable against thermal curing‐induced disconnections at the channel‐electrode interfaces. The screen‐coating technique is also available for whole device materials of solution‐processable CNT film PTE imagers, simplifying fabrication processes. All‐screen‐coatable CNT film PTE imagers synergize their inherent functional sensing and high‐yield operations toward versatile applications.
Au(I) and HOTf‐Catalyzed Cascade [5+1]‐Annulations between Allenylacetals and Diazo Esters To Form 1,3‐ and 2,3‐Disubstituted Naphthoates, Respectively
Authors: Bhausaheb Dawange Satish , Liu Rai‐Shung 
Published: September 2023

AbstractGold‐catalyzed [5+1]‐annulations between allenylacetals with diazo esters to form 1,3‐disubstituted naphthoate derivatives are described. Notably, this reaction chemoselectivity is switched to 2,3‐naphthoate products when using the HOTf catalyst. Mechanistic studies of these reactions support an acetal activation, in which oxoniums are formed initially, followed by attack of the allene, generating allyl cations to trap α‐diazo esters. In gold catalysis, such diazo addition intermediates undergo Roskamp rearrangement, whereas in HOTf catalysis the same intermediates undergo a Conia‐ene reaction instead.
Ring‐Opening‐Recombination Strategy Based on 2‐Methylbenzothiazole Salts: Syntheses of Thiazinopyrrole Fused‐Ring Derivatives
Authors: Xu Shengting , Zhu Zhongzhi , Yang Zhendong , Mai Zuyu , Chen Tianxiang , Ma Aijun , Chen Xiuwen 
Published: September 2023

AbstractThis study presents a method for the synthesis of thiazinopyrrole fused ring derivatives utilizing a ring‐opening recombination strategy with benzothiazole salts. Thiazolium salts, aldehydes, and amines undergo a cascade cyclization reaction in a one‐pot under the solvent conditions of ethanol.
Expanding Synthetic Applications of Δ1‐Piperidine‐2‐carboxylate/Δ1‐pyrroline‐2‐carboxylate Reductase from Pseudomonas syringae (DpkAPsyrin). Biocatalytic Asymmetric Synthesis of (S,E)‐2‐hydroxy‐4‐arylbut‐3‐enoic Acid Derivatives
Authors: Moreno Carlos J. , Gittings Samantha , Schollmeyer Dieter , Joglar Jesús , Bujons Jordi , Hernández Karel , Clapés Pere 
Published: September 2023

AbstractChiral 2‐hydroxy‐4‐arylbut‐3‐enoic acid derivatives are important precursors for the synthesis of angiotensin converting enzyme (ACE) inhibitors, such as enalapril, lisinopril, cilapril or benazepril. In this work, we take advantage of the unexplored promiscuous ketoreductase activity of Δ1‐piperidine‐2‐carboxylate/Δ1‐pyrroline‐2‐carboxylate reductase from Pseudomonas syringae pv. tomato DSM 50315 (DpkAPsyrin) for the synthesis of (S,E)‐2‐hydroxy‐4‐arylbut‐3‐enoic acids. The strategy was designed as an enzymatic cascade comprising an aldol condensation between pyruvate with aryl aldehydes, catalyzed by the trans‐o‐hydroxybenzylidene pyruvate hydratase‐aldolase from Pseudomonas putida (HBPAPputida), for the construction of carbon scaffold, and an ensuing asymmetric reduction of the carbonyl group catalyzed by DpkAPsyrin. The enzymatic cascade provided quantitative conversions, with global isolated yields between 57–85%. A total of nine structurally diverse (S,E)‐2‐hydroxy‐4‐arylbut‐3‐enoic acids were prepared in ee between 87–99%.