bluuebunny/crossref_metadata_2025 huggingface dataset:
Manganese‐Catalyzed CH Functionalization Reactions of Arenes
Authors: Sen Subhabrata , Prabakar Tejas
Published: October 2022

Manganese‐catalyzed CH functionalization reactions have evolved as an efficient strategy to construct new CC, CN, CO, and CS bonds and provide an alternative pathway to classical cross‐coupling reactions. Unlike the classical cross‐coupling catalysts like palladium (Pd) and iridium (Ir) or toxic 4d and 5d transition metal catalysts like rhenium (Re) and rhodium (Rh) that have been used for CH functionalization, 3d transition metals will be an excellent choice. Manganese is one of the most nontoxic and earth‐abundant metals available at a very low cost. Subsequently, usage of manganese catalysts has vastly increased mainly because of their application in the synthesis of active pharmaceutical ingredients. Herein, we will discuss various arene and olefin CH functionalization reactions catalyzed by manganese and assisted by diverse directing groups. The article will culminate in a discussion of the applications of manganese‐catalyzed CH functionalization via radical pathways for the generation of interesting heterocycles.
Asymmetric CH Oxygenation Reactions
Authors: Bryliakov Konstantin P.
Published: October 2022

This article surveys the catalytic approaches to asymmetric oxygenation of aliphatic CH groups of organic molecules. The progress of catalysts, both transition metal‐based and organocatalysts (excluding enzymatic systems), over the last three decades is analyzed, with a focus on synthetic aspects of the title oxidative transformations. Herewith, stereoselective processes relying on enantioselective oxofunctionalizations (essentially, net hydroxylations) of prochiral CH groups, as well as oxidative desymmetrizations (through either ketonization or hydroxylation) are considered.

This account mostly puts forward environmentally benign processes and catalysts, including biomimetic, or bioinspired, catalyst systems. Basic elements of the state‐of‐the‐art mechanistic landscape of stereoselective CH oxygenations are discussed briefly.
Transition Metal‐Catalyzed Atroposelective CH Functionalization
Authors: Rahim Abdur , Gu Zhenhua
Published: October 2022

Atropisomeric biaryls are one of the important motifs which are highly essential in ligands, biologically active molecules, and natural products. For the synthesis of atropisomeric biaryl and vinylarene derivatives, the transition metal‐catalyzed CH functionalization has been documented as a promising strategy. This article is planned to summarize the research in the field of biaryl atropisomer synthesis within the scope of transition‐metal catalyzed CH bond functionalization. Research regarding atroposelectivity in CH activation procedures and the applications of these novel ideas for the improvement of new‐fashioned carbon–carbon and carbon–heteroatom bond‐featuring reactions are described. Throughout this article, a particular emphasis is placed on the development of CH functionalization strategies that are relevant in the reign of atroposelective synthesis of chiral biaryl and vinylarene analogs.
Mechanistic Insights on Palladium‐Catalyzed C(sp
2
)H Functionalization from Theoretical Perspective
Authors: Zhang Xinglong , Maiti Debabrata
Published: October 2022

Palladium‐catalyzed C(sp
2
)H functionalization is a powerful tool for the manipulation and synthesis of complex pharmachemical, agrochemical, and medicinal molecules. In this article, we survey the general modes of Pd‐catalyzed CH activation. From computational perspective, we dissect the roles of ligands (such as carboxylate‐type ligands, pyridone‐based ligands, and mono‐protected amino acids), solvents, and silver additives in crucial CH activation event facilitated via generally accepted concerted metalation deprotonation (CMD) mechanism. In addition, we present the computational evidence for mono‐ vs multinuclearity of palladium catalysts in C(sp
2
)H functionalization. Template‐assisted regioselective C(sp
2
)H functionalization via ring strain control is also discussed.
Recent Developments on Transition Metal‐Free CC Cross‐Coupling Reactions Using Recyclable Catalysts
Authors: Singh Bhagat , Sreejyothi P. , Mandal Swadhin K.
Published: October 2022

Molecular scaffolds possessing biaryl moiety accorded high priority in modern science because of their application in pharmaceuticals, agrochemicals, and natural products. Activation of carbon–halogen bond is one of the leading methodologies to construct these moieties in advanced synthetic organic chemistry. In its initial phase, these biaryl molecules were constructed through the coupling between aryl halides and organometallic reagents employing transition metal‐based catalysts. Evolution in this field substituted one of the prefunctionalized partners with simple arene molecules and flourished as direct CH arylation, even without the assistance of any transition metal‐based catalysts. From an industrial perspective, surrogating metal catalysts with organocatalysts is highly important as it reduces metal waste. But the state‐of‐the‐art technology demands the utilization of heterogeneous catalysts that are easily separable and recyclable. In the this article, we highlight the recent developments made in the field of transition metal‐free CC cross‐coupling reactions using heterogeneous catalysts.
Regioselective C(sp
2
)H Functionalization of Anilines
Authors: Cheung Chi Wai
Published: October 2022

The chemical bond transformations of anilines and their derivatives allow for their valuable derivatizations for multiple applications in academia and industry. Here, the C(sp
2
)H functionalizations of anilines and their
N
‐alkyl and
N
‐aryl counterparts are demonstrated with recent representative examples. Under transition metal catalysis and catalyst‐free reaction conditions, the aromatic
ortho
,
meta
, and
para
CH bonds of anilines can be converted to variegated carbon–carbon and carbon–heteroatom bonds in chemo‐ and regioselective manners, shedding light on the powerful synthetic utility of direct C(sp
2
)H functionalization of anilines.
CH Bond Borylation and Silylation via Iron Catalysis
Authors: Zhang Juan , Feng Zhang
Published: October 2022

Organoboron and organosilicon compounds are powerful building blocks in organic synthesis and are widely employed in Suzuki–Miyaura and Hiyama cross‐coupling reactions. Various methods for the construction of CB and CSi bonds have been developed. This article focuses on CH bond borylation and silylation of (hetero)arenes, alkenes, and alkanes via iron catalysis. Additives, irradiation, active iron complexes, or bimetallic Cu–Fe complexes are always required in these transformations. In addition, the efficiency of C(sp
3
)H bond borylation and CH bond silylation is still inferior, and mechanistic studies remain to be developed.
Carboxylate‐Directed CH Functionalization
Authors: Li Wanting , Wu Jiahao , Wang Yu , Gooßen Lukas J. , Huang Liangbin
Published: October 2022

Transition metal‐catalyzed transformations involving converting CH bonds into CC or CX bond have been extensively explored, which expedite the synthesis of target molecules via novel and efficient disconnections in retrosynthetic analysis. Directing group‐assisted CH activation is one of the most used strategy to obtain site‐selective CH functionalization. Ideal directing groups are ubiquitously available, stable, easily removed, and transformable. Carboxylates perfectly meet with those prerequisites. Carboxylic acids widely exist in organic molecules, which can be tracelessly removed by protodecarboxylation or converted into other functional groups. Thus, carboxylate‐directed CH activation is of significant importance.
Strain Release of Bicyclic/Tricyclic Olefins via CH Functionalization Reactions
Authors: Prakash Praveen , Vijayan Ajesh , Radhakrishnan Kokkuvayil Vasu
Published: October 2022

Bicyclic/tricyclic olefins have gathered considerable attention among the synthetic organic community owing to their highly reactive bi‐ or tricyclic structure that imparts steric, torsional, and angular strains. The present article highlights the significant transformations of these strained olefins via transition metal‐catalyzed transformations using metal catalysts such as palladium, rhodium, ruthenium, iridium, rhenium, cobalt, and nickel. In this article, we have selected a few strained olefins such as diazabicyclic olefins, oxa/azabicyclic olefins, and bicyclic olefins derived from urea derivatives and have illustrated the construction of various carbo‐ and heterocycles from these strained moieties, and the mechanisms for their synthesis are also demonstrated for selected examples. Considering the significance of the synthesis of biologically relevant molecules and their prevalence in various natural products, pharmaceuticals, and agrochemicals, reactions such as cycloadditions, cyclizations, and couplings are important for high yields of the desired products which are otherwise difficult to achieve via traditional synthetic strategies.
Photoorganocatalyzed Direct Hydrogen Atom Transfer (HAT): A Tool for Transition Metal‐Free CC Bond Formation
Authors: Protti Stefano , Fagnoni Maurizio , Ravelli Davide
Published: October 2022

Photocatalytic hydrogen atom transfer (HAT) is a valid tool for the functionalization of aliphatic CH bonds in a mild way, offering a straightforward path to ameliorate the step and atom economy of synthetic processes. Thus, carbon‐centered radicals are smoothly generated via a homolytic CH cleavage and they are mainly used to forge valuable CC bonds. Among the photocatalysts available, both metal‐containing derivatives and organic compounds are viable options in some respect. However, the adoption of the latter class of photocatalysts is appreciated from an environmental point of view, since the desired products are free from metal contaminants. In this frame, the aim of this article is to collect the processes (mainly the most recent ones) making use of a photoorganocatalyst (POC
HAT
) for the generation via HAT of carbon‐centered radicals, in turn, used for diverse synthetic purposes. These include hydroalkylation and hydroacylation of olefins, along with the preparation of alkenes, alkynes, and substituted heteroaromatics.
Selective Functionalization of Arenes and Heteroarenes via S
E
Ar and Related Transformations
Authors: Nguyen Ashley D. , Zanolini Ryan J. , Gustafson Jeffrey L.
Published: October 2022

Electrophilic aromatic substitution (S
E
Ar) is among the classic routes toward the functionalization of aromatic CH bonds. There are a myriad of functionalities that can be introduced into aromatic systems via S
E
Ar, including but not limited to halogens, perfluoroalkyl, sulfenyl, alkyl, acyl, and nitro substitutions. S
E
Ar has become increasingly common in modern synthetic chemistry as many of the potential products, particularly halogenated arenes, have become important building blocks in drug discovery and other endeavors. Despite its widespread application, S
E
Ar is hindered by several issues that have historically prevented its use on more complex systems. These issues include a reliance on strongly acidic conditions and a lack of regioselectivity. In this article, we will discuss recent advances, from the past vicennial, in S
E
Ar methodology with a focus on new reagents and catalytic strategies that alleviate many of these issues for halogenation, sulfenylation, and perfluoroalkylation.
Iridium‐Catalyzed CH Functionalizations with Hydrogen Isotopes
Authors: Derdau Volker
Published: October 2022

This overview discusses some highlights of iridium catalyzed CH functionalizations with hydrogen isotopes. The hydrogen isotope exchange (HIE) reaction has become the gold standard in late stage functionalization and synthesis of deuterium or tritium labelled organic, complex molecules. In particular, new highly selective and reactive protocols in the areas of acid/base, nanoparticle, metal‐ catalyzed or photoredox catalysis are reported.
Visible‐Light‐Driven CH Bond Functionalization of Amine Derivatives
Authors: Akita Munetaka
Published: October 2022

Recent developments in CH bond functionalization of amine derivatives driven by visible‐light photoredox catalysis (
PRC
) are summarized.
PRC
promotes the generation of organic radicals via single‐electron transfer (SET) under mild reaction conditions. Functionalizations are categorized according to the four reactive intermediates generated by
PRC
: N‐centered radicals (aminium cation radicals and aminyl radicals) and C‐centered active species (iminium cations and α‐aminoalkyl radicals). The radical‐generating systems by
PRC
can be combined with other catalytic systems such as cross‐coupling and hydrogen atom transfer (HAT) to lead to more sophisticated dual and triple catalytic systems, which result in efficient functionalization of the hydrocarbyl substituents in amines. In addition to
PRC
, energy transfer and electron donor–acceptor complex have attracted increasing attention as alternative utilization methods of visible‐light energy. Reactions of relevant amide and imine derivatives are also included.
Mechanically Tissue‐Like and Highly Conductive Au Nanoparticles Embedded Elastomeric Fiber Electrodes of Brain–Machine Interfaces for Chronic In Vivo Brain Neural Recording
Authors: Won Chihyeong , Jeong Ui‐Jin , Lee Sanghyeon , Lee Minkyu , Kwon Chaebeen , Cho Sungjoon , Yoon Kukro , Lee Seungmin , Chun Dongwon , Cho Il‐Joo , Lee Taeyoon
Published: October 2022

Implantable neural probes are a crucial part of brain–machine interfaces that serve as direct interacting routes between neural tissues and machines. The neural probes require both mechanical and electrical properties to acquire high‐quality signals from individual neurons with minimal tissue damage. However, overcoming the trade‐off between flexibility and electrical property is still challenging. Herein, a fiber neural probe, composed of core polymer and Au nanoparticles (AuNPs) on the outer shell, is fabricated by absorbing Au precursor following in situ chemical reduction with a variation of percolating and leaching time. The proposed fiber exhibits excellent electrical properties, with an electrical conductivity of 7.68 × 104 S m−1 and an impedance of 2.88 × 103 Ω at 1 kHz, as well as a Young's modulus of 170 kPa, which is comparable to that of brain tissue (≈100 kPa). Additionally, the AuNPs fiber neural probe demonstrates extremely stable in vivo electrophysiological signal recordings for four months with reduced foreign body responses at the tissue–probe interface. Furthermore, this innovative approach encourages a new paradigm of long‐term recording in the fields of neuroscience and engineering to better understand brain circuits, develop bioelectronic devices, and treat chronic disorders.
Biomimetic Synthesis of VOx@C Yolk‐Shell Nanospheres and Their Application in LiS Batteries
Authors: Ji Mingze , Ni Jie , Liang Xing , Cheng Qian , Gao Guohua , Wu Guangming , Xiao Qiangfeng
Published: October 2022

Many biological processes involve active transport where the desired substances can be transported against the concentration gradient with energy consumption. This feature is highly desirable for the synthesis of yolk‐shell structures using preformed capsules to efficiently encapsulate yolk materials. Here, the synthesis of VOx@C yolk‐shell nanospheres by biomimicking prey–predation of carnivorous Utricularia is reported. The high intrinsic frequency and superior mechanical properties of hollow mesoporous carbon spheres (HMCS) maintain their integrity during ultrasonication, making HMCS an ideal capsule. Numerical simulation elucidates that the encapsulation of the VOx nanoparticles is ascribed to the periodic change of pressure and the damping force generated from the relative motion between the mesoporous tunnel in the HMCS and VOx nanoparticles. The resulting VOx@C yolk‐shell nanospheres demonstrate promising application as a regenerative polysulfide‐scavenging layer (RSL) for high‐loading LiS batteries (≈5 mAh cm−2). As compared with the cells with a commercial Celgard polypropylene (PP) separator, those with a RSL present improved capacity retention from 467 to 860 mAh g−1 after 100 cycles, superior rate capability, and reduced impedance. This method provides an additional synthesis tool for yolk‐shell materials otherwise inaccessible by conventional methods with potential applications in energy storage and conversion devices.
In‐Memory Computing of Multilevel Ferroelectric Domain Wall Diodes at LiNbO3 Interfaces
Authors: Sun Jie , Li Yiming , Ou Yangjun , Huang Qianwei , Liao Xiaozhou , Chen Zibin , Chai Xiaojie , Zhuang Xiao , Zhang Wendi , Wang Chao , Jiang Jun , Jiang Anquan
Published: October 2022

Direct data processing in nonvolatile memories can enable area‐ and energy‐efficient computation, unlike independent performance between separate processing and memory units; repetitive data transfer between these units represents a fundamental performance limitation in modern computers. Spatially mobile conducting domain walls in ferroelectrics can be redirected between drain, gate, and source electrodes to function as nonvolatile transistors with superior energy efficiency, ultrafast operating and communication speeds, and high logic/storage densities. Here, in‐memory computing is demonstrated using multilevel domain wall diodes at LiNbO3 interfaces. Ultrathin domains within interfacial layers between each mesa‐like memory cell and the contact electrodes can rectify diode‐like domain wall currents with on/off current ratios exceeding 107 at low operating voltages, surpassing the performance of traditional p‐n junctions using built‐in potentials across depletion layers. NOT, NAND, and NOR gate logic functions are demonstrated, providing insights into high‐density integration of multilevel storage and computational units in all‐ferroelectric domain wall devices.
Infrared‐Reflective Transparent Hyperbolic Metamaterials for Use in Radiative Cooling Windows
Authors: Jin Yeonghoon , Jeong Youngjae , Yu Kyoungsik
Published: October 2022

Passive multilayer coatings for windows have potential to improve energy consumption for indoor temperature regulation. The coatings should block the solar IR energy (800–2500 nm) while maintaining visible light transparency (400–700 nm) to prevent unwanted heating of the interior of a building or a vehicle. It should also efficiently radiate thermal energy to prevent excessive heating. Although solar energy management and radiative cooling techniques have been investigated individually, the combination of the two, a transparent radiative cooler, has emerged only recently. This study theoretically and experimentally demonstrates a transparent radiative cooling window using a combination of planar hyperbolic metamaterials and a uniform layer of polydimethylsiloxane, resulting in high visible transparency (>60%), IR reflectivity (>89%), and thermal emissivity (>95%). Daytime temperature experiments confirm that the cooling window efficiently lowers the interior temperature by as much as 7 °C.
Oxygen Vacancy‐Rich Sr2MgSi2O7:Eu2+,Dy3+ Long Afterglow Phosphor as a Round‐the‐Clock Catalyst for Selective Reduction of CO2 to CO
Authors: Pei Lang , Ma Zhanfeng , Zhong Jiasong , Li Weirong , Wen Xin , Guo Junjie , Liu Peizhi , Zhang Zhenhua , Mao Qinan , Zhang Jian , Yan Shicheng , Zou Zhigang
Published: October 2022

Solar‐driven CO2 conversion to fuels is a central technique for closing the anthropogenic carbon cycle, but to date is limited by the intermittent solar flux. To face this challenge, a catalyst is needed that can work well in both light and dark. Here, surface oxygen vacancies are created in a Sr2MgSi2O7:Eu2+,Dy3+ long‐afterglow phosphor with long‐time and high charge storage capacity (denoted as Vo‐SMSED) as both electron transfer station and active sites for molecule activation. The strong ability for oxygen vacancies to store and extract electrons from charge storage centers enables the Vo‐SMSED to work efficiently in both light and dark. As a result, Vo‐SMSED manifests nearly 100% selectivity for catalyzing CO2 reduction by H2O to CO with high light stability and over 3 h dark activity. These results demonstrate that creating the bifunctional sites as electron‐storing/extracting and molecule‐activating center is an efficient route to change the long‐lived charge into the highly active species for catalysis, thus making the long‐afterglow phosphors with high charge storage capacity a highly efficient round‐the‐clock photocatalyst.
Electronic Delocalization Regulates the Occupancy and Energy Level of Co 3dz2 Orbitals to Enhance Bifunctional Oxygen Catalytic Activity
Authors: Zhang Yun‐Long , Liu Bo , Dai Yun‐Kun , Xia Yun‐Fei , Guo Pan , Liu Yang‐Yang , Kong Fantao , Zhang Qianyu , Zhao Lei , Wang Zhen‐Bo
Published: October 2022

Cobalt–nitrogen–carbon is hitherto considered as one of the most satisfactory alternatives to precious metal catalysts for oxygen electrocatalysts. However, precisely tuning the local coordination of Co sites and thus engineering d‐orbital electron configuration to optimize the binding energy of the intermediates remains a huge challenge. Herein, a robust electrostatic self‐assembly strategy is developed to engineer penta‐coordinated Co sites by introducing axial O ligands with atomic‐level precision to form CoN4O1 configurations on MXene nanosheets (CoN4‐O/MX). The optimized CoN4‐O/MX demonstrates outstanding bifunctional electrocatalytic performance with a small potential gap of 0.72 V, significantly outperforming the cobalt–nitrogen–carbon catalyst with plane‐symmetric CoN4 sites and precious metal counterparts. The Zn–air batteries integrated with CoN4‐O/MX provide an outstanding peak power density of 182.8 mW cm−2 and a long‐term cyclability for 250 h. Density functional theory calculations reveal that CoO coordination induces electronic delocalization to draw off partial electrons from the dz2 orbital, which forms unsaturated orbital filling and lifts the energy level, resulting in a stronger Lewis basicity to facilitate electron injection into the intermediate. The study presented here provides not only a novel methodology to achieve precise control of heteroatom coordination, but also a fundamental understanding about the structure–activity relationships of dz2 orbitals.
Highly Stable Single‐Atom Modified MXenes as Cathode‐Active Bifunctional Catalysts in Li–CO2 Battery
Authors: Shi Yu , Wei Bo , Legut Dominik , Du Shiyu , Francisco Joseph S. , Zhang Ruifeng
Published: October 2022

The exploration of cathode catalysts with low overpotentials for the carbon dioxide reduction reaction (CRR) and carbon dioxide evolution reaction (CER) is essential for Li–CO2 batteries. MXenes have been suggested as potential candidates owing to their high electrical conductivity and effective CO2 activation performance. Herein, the stability and bifunctional CRR/CER catalytic activities of bare MXene (M2C), oxygen‐functionalized MXene (M2CO2), and single‐atom (SA) modified M2CO2 are systemically investigated. Among bare MXenes, Mo2C exhibits the best catalytic activity, comparable to that of carbon nanotubes, whereas oxygen‐functionalized MXene has poor activity. Notably, introducing an SA on the surface of oxygen‐functionalized MXene decreases the overpotential by 12.2%–68.1%, which can even outperform graphene catalysts, suggesting their potential as bifunctional cathode catalysts in Li–CO2 batteries. This high activity is appropriate reactivity in origin, as highlighted by the volcano‐type relationship between the Gibbs free energy and the overpotential for key steps. The descriptor ξ, which is related to adsorption behavior, is effective in determining bifunctional catalytic activity, which depends on the ability of SA electrons to fill antibonding orbitals and SA–oxygen/carbon bonding. This study not only identifies promising MXene‐based bifunctional CRR/CER catalysts but also provides a rational design rule for SA modified catalysts.
Mussel Byssus Inspired Ionic Skin with Damage‐Resistant Signal for Human–Machine Interaction
Authors: Wang Wenkai , Song Huaiyu , Lu Zekang , Zeng Qing , Wang Qinghao , Ma Cheng , Jin Hongjun , Qi Jinwan , Wu Tongyue , Gao Shuitao , Zhu Mingning , Lu Dongdong , Huang Jianbin , Yan Yun
Published: October 2022

Reliable human–machine interactions rely highly on a material that can provide stable real‐time conductivity in the presence of unexpected damage. The closest step toward this goal is to create various self‐healing materials, but the performance of the material will inevitably be interrupted during the process of healing. Herein, it is reported that damage‐resistant conductivity of a skin‐like polyelectrolyte film electrode can be achieved by creating hierarchical pores in analogy to those in mussel byssus. The hierarchical porous structure in mussel byssus is well‐known to expel water quickly from the rock surface, but its role in recovering the ionic conductivity has been overlooked. It is shown that the ionic conductivity in the porous film remains stable as long as a small part of the film is still in contacting, owing to the fast ion transportation in the hierarchical pores. As such, the real‐time conductivity does not change even if the skin‐like film is cut with a knife or pieced with a needle during work. It is envisioned that the current damage‐resistant ionic electrode wants to open a new vista in the design of soft conductive devices for reliable human–machine interactions.
Voltage Signals Caused by Surface Acoustic Wave Driven Ferromagnetic Resonance Under Out‐of‐Plane External Fields
Authors: Hwang Yunyoung , Puebla Jorge , Kondou Kouta , Otani Yoshichika
Published: October 2022

Under an external magnetic field, surface acoustic waves (SAWs) propagating onto a ferromagnetic thin film can excite ferromagnetic resonance (FMR). The magnetization precessional motion in resonance pumps spin current into the Rashba interface across an adjacent non‐magnetic layer, which can be converted to charge current via the inverse Edelstein effect (IEE). Here, the SAW‐driven FMR and the IEE voltage signals under in‐ and out‐of‐plane external magnetic fields are reported. When the external magnetic field has only an in‐plane component, the SAW‐driven FMR for positive and negative resonant fields have the same sign (even), while the spin‐conversion due to IEE results in voltage signals with opposite signs for positive and negative fields (odd). However, when the out‐of‐plane component of the external magnetic field increases, the acoustic ferromagnetic resonance signal remains even. In contrast, the IEE voltage signal exhibits a sum of even and odd signal contributions. It is discussed that the appearance of the even contribution to the voltage signal does not correspond to well‐known spin rectification mechanisms. The result may constitute a novel resonant spin rectification mechanism under SAW excitations.
Perpendicularly Magnetized MnxGa‐Based Magnetic Tunnel Junctions: Materials, Mechanisms, Performances, and Potential Applications
Authors: Zhao Xupeng , Zhao Jianhua
Published: October 2022

Magnetic tunnel junctions (MTJs) exhibit a great profusion of unique functional properties, such as nonvolatility, scalability, high endurance, and low power consumption. For this reason, they have been widely investigated in spin‐based logic and memory devices. Compared with conventional in‐plane MTJs, perpendicular MTJs (pMTJs) enable lower critical switching current and higher integration density. So far, CoFeB/MgO structures with interface‐induced perpendicular magnetic anisotropy (PMA) are the most common ferromagnetic (FM) electrodes in pMTJs, whereas their relatively weak interfacial PMA restricts further development of device nodes. In the past decade, perpendicularly magnetized MnxGa binary alloys, including FM L10‐MnGa and ferrimagnetic D022‐Mn3Ga, have drawn intense attention for serving as a promising magnetic electrode in various MTJ stacking structures because of their large PMA, high spin polarization, and small magnetic damping constant. From an application perspective, MTJs with ultrathin MnxGa electrode show merits in developing high‐density magnetic memory, high‐frequency spin‐torque oscillators, and tunneling magnetoresistance effect‐based high‐field sensors. Herein, the aim is to provide a comprehensive review of recent progress in perpendicularly magnetized MnxGa‐based MTJs. The conclusions and future prospects are also given to inspire more in‐depth research and advance the practical applications.
Critical Role of Terminating Layer in Formation of 2DEG State at the LaInO3/BaSnO3 Interface
Authors: Kim Seonghyeon , Lippmaa Mikk , Lee Jaehyeok , Cho Hyeongmin , Kim Juhan , Kim Bongju , Char Kookrin
Published: October 2022

Based on the interface polarization model, the 2D electron gas (2DEG) at LaInO3(LIO)/BaSnO3(BSO) interfaces is understood to originate from a polarization discontinuity at the interface and the conduction band offset between LIO and BSO. In this scenario, the direction of polarization at the interface is determined by whether the first atomic LIO layer at the interface is LaO+ or InO2−. The role of the terminating layer is investigated at the LIO/BSO interface in creating the 2DEG. Based on conductance measurements of the in situ grown LIO/BSO heterostructures, it has been reported in this work that the 2DEG only forms when the BSO surface is terminated mainly with a SnO2 layer. The terminating layer is controlled by additional SnO2 deposition on the BSO surface. It has been shown that the as‐grown BSO surface has a mixed terminating layer of BaO and SnO2 while the BSO surfaces prepared with additional SnO2 deposition are terminated mainly with the SnO2 layer. The terminating layer is confirmed by coaxial impact collision ion scattering spectroscopy. The finding is consistent with the interface polarization model for 2DEG formation at LIO/BSO interfaces, in which the direction of the interfacial polarization in LIO is determined by the terminating layer of the BSO surface.
Self‐Powered 2D MoS2/WOx/WSe2 Heterojunction Photodetector Realized by Oxygen Plasma Treatment
Authors: Shin Hoseong , Taqi Muhammad , Ali Fida , Lee Sungwon , Choi Min Sup , Kim Cihyun , Lee Byoung‐Hun , Liu Xiaochi , Sun Jian , Oh Byungdu , Yoo Won Jong
Published: October 2022

2D transition metal dichalcogenides (TMDCs) are anticipated to be the ones of future nano‐sized photodevices due to their electronic and optoelectronic properties. They have shown remarkable performances as photodetectors from being fabricated into heterostructures with p–n junction. An oxygen plasma‐doped WSe2/pristine MoS2‐based photodetector with high responsivity and broad detection spectrum ranging from visible to near‐infrared (NIR) region is reported. The oxygen plasma treatment forms a WOx layer on WSe2 that not only acts as a p‐dopant but also an interfacial oxide layer to suppress dark current to as low as ≈pA. Under illumination of visible light (520 nm in this study), greatly enhanced photoresponsivity and specific detectivity of thus fabricated devices are achieved without applying an external bias, in contrast to untreated devices. The devices have also exhibited good photodetection in the NIR region with two orders enhanced photoresponsivity under the illumination of 852 nm light at room temperature. It is confirmed from photomapping measurements that the photocurrent is mainly generated from p–n heterojunction. These results indicate that oxygen plasma‐doped WSe2‐based heterojunctions can be used as highly sensitive and self‐powered photodetectors.
Spray Pyrolyzed Amorphous InGaZnO for High Performance, Self‐Aligned Coplanar Thin‐Film Transistor Backplanes
Authors: Bae Jinbaek , Ali Arqum , Jang Jin
Published: October 2022

High‐performance, spray‐pyrolyzed amorphous indium‐gallium‐zinc oxide (a‐IGZO) thin‐film transistor (TFT) with self‐aligned (SA) coplanar structure is demonstrated. The spray‐pyrolyzed a‐IGZO film exhibits bubbles‐free smooth surface roughness (0.81 nm) and low oxygen‐related defects (22.5%). The fluorine‐doped a‐IGZO film shows a low resistivity of 1.18 × 10−3 Ω‐cm by NF3 plasma treatment. This is sufficient to obtain ohmic contact with the source/drain electrodes and doped IGZO in the offset region of the SA coplanar TFT. The spray‐pyrolyzed a‐IGZO TFT exhibits the field‐effect mobility (µFE) of 18.17 cm2 V−1 s−1, the threshold voltage (VTH) of −1.52 V, the subthreshold swing (SS) of 0.266 V dec−1, and a high on/off current ratio (Ion/Ioff) over 108 with a very low gate leakage current (<10−13 A). The hysteresis‐free and highly stable performances are achieved due to the excellent a‐IGZO channel and SiO2 gate insulator interface. A twenty‐three‐stage ring oscillator is demonstrated with SA coplanar TFTs, exhibiting a high oscillation frequency of 2.66 MHz and a low propagation delay of 8.17 ns/stage. Therefore, the spray‐pyrolyzed a‐IGZO film can be a promising metal oxide semiconductor for high‐performance TFTs backplane in large areas and high‐resolution display applications.
Plasmon Coupling—The Root Cause of Raman Anomaly and Laser Cooling in Nanocrystal Ge
Authors: Ebrahimi Manuchehr , Helmy Amr S. , Kherani Nazir P.
Published: October 2022

Laser cooling of matter through anti‐Stokes photoluminescence, where the emitted frequency of light exceeds that of the impinging laser light by virtue of absorption of thermal vibrational energy, has been successfully realized in condensed media, and in particular with rare‐earth‐doped systems achieving sub‐100 K solid‐state optical refrigeration. Studies suggest that laser cooling in semiconductors has the potential of achieving temperatures down to ≈10 K and that its direct integration can usher in unique high‐performance nanostructured semiconductor devices. While laser cooling of nanostructured II–VI semiconductors has been reported recently, laser cooling of indirect bandgap semiconductors such as group IV silicon and germanium remains a major challenge. Herein, the anomalous observation of dominant anti‐Stokes photoluminescence in germanium nanocrystals principally associated with plasmon coupling is reported. Specifically, this Raman anomaly to the confluence of ultrahigh‐purity nanocrystal germanium, generation of high density of electron–hole plasma, the inherent degeneracy of longitudinal and transverse optical phonons in nonpolar indirect bandgap semiconductors, and simultaneous spatial confinement effects are attributed. At high laser intensities, plasmon‐assisted laser cooling with lattice temperature as low as ≈50 K is inferred.
Schisandrin B Attenuates Diabetic Cardiomyopathy by Targeting MyD88 and Inhibiting MyD88‐Dependent Inflammation
Authors: Luo Wu , Lin Ke , Hua Junyi , Han Jibo , Zhang Qiuyan , Chen Lingfeng , Khan Zia A. , Wu Gaojun , Wang Yi , Liang Guang
Published: October 2022

Diabetes manifests as chronic inflammation and leads to the development diabetic cardiomyopathy (DCM). Targeting key proteins in inflammatory signaling may provide new therapy for DCM. In this study, the authors explore the pharmacological effects and mechanisms of Schisandrin B (Sch B), a natural compound with anti‐inflammatory activity against DCM. It is shown that Sch B prevents high‐level glucose (HG)‐induced hypertrophic and fibrotic responses in cultured cardiomyocytes. RNA sequencing and inflammatory qPCR microarray show that Sch B mainly affects myeloid differentiation primary response 88 (MyD88)‐dependent inflammatory gene expression in HG‐challenged cardiomyocytes. Further studies indicate that Sch B directly binds to and inhibits MyD88 activation, but does not alter MyD88‐independent Toll‐like receptor signaling in vivo and in vitro. Inhibiting or silencing MyD88 is associated with reduced levels of HG‐induced inflammatory cytokines and myocardial injuries in vitro. Treatment of type 1 and type 2 diabetic mice with Sch B protects heart function, reduces myocardial injuries, and decreases secretion of inflammatory cytokines. Cardiomyocyte‐specific MyD88 knockout also protects mice against cardiac inflammation and injury in type 1 diabetic mice. In conclusion, these studies show that cardiomyocyte MyD88 plays an apathogenetic role in DCM and Sch B specifically targets MyD88 to reduce inflammatory DCM.
Portable Cold Atmospheric Plasma Patch‐Mediated Skin Anti‐Inflammatory Therapy
Authors: Kim Namkyung , Lee Seunghun , Lee Soyoung , Kang Jinjoo , Choi Young‐Ae , Park Jeongsu , Park Chul‐Kyu , Khang Dongwoo , Kim Sang‐Hyun
Published: October 2022

Although plasma is a promising technology in various fields, its clinical application is restricted by several limitations. A cold atmospheric plasma (CAP) patch is fabricated to help overcome hurdles, especially when treating skin diseases. This patch has surface dielectric barrier discharge, which generates reactive oxygen species (ROS) and reactive nitrogen species (RNS) on a flexible polymer film surface on which the embedded electrode induces a locally strong electric field. The effect of the CAP patch on psoriasis is also evaluated. The distinct characteristics of psoriasis between the lesion and non‐lesion area allow the CAP patch to be suitable for only lesion area for its treatment. The CAP patch induces the opening of calcium channels in keratinocytes, thereby restoring abnormal keratinocyte differentiation and the collapse of the tight junction; thus, alleviating psoriatic symptoms. In addition, the favorable effect is due to the induction of ROS/RNS by the CAP patch, not the electric field generated during plasma generation. The findings indicate that the proposed portable CAP patch can help treat inflammatory skin disorders, especially psoriasis. As this can be used easily as a combination therapy with existing drugs, it may help reduce side effects caused by existing drugs.
Materials Genomics Search for Possible Helium‐Absorbing Nano‐Phases in Fusion Structural Materials
Authors: Xu Haowei , Kim So Yeon , Chen Di , Monchoux Jean‐Phillippe , Voisin Thomas , Sun Cheng , Li Ju
Published: October 2022

Civilian fusion demands structural materials that can withstand the harsh environments imposed inside fusion plasma reactors. The structural materials often transmute under 14.1 MeV fast neutrons, producing helium (He), which embrittles the grain boundary (GB) network. Here, it is shown that neutron‐friendly and mechanically strong nano‐phases with atomic‐scale free volume can have low He‐embedding energy and >10 at.% He‐absorbing capacity, and can be especially advantageous for soaking up He on top of resisting radiation damage and creep, provided they have thermodynamic compatibility with the matrix phase, satisfactory equilibrium wetting angle, as well as a high enough melting point. The preliminary experimental demonstration proves that is a good ab initio predictor of He shielding potency in nano‐heterophase materials, and thus, is used as a key feature for computational screening. In this context, a list of viable compounds expected to be good He‐absorbing nano‐phases is presented, taking into account , the neutron absorption and activation cross‐sections, the elastic moduli, melting temperature, the thermodynamic compatibility, and the equilbrium wetting angle of the nano‐phases with the Fe matrix as an example.
Diamagnetic Composites for High‐Q Levitating Resonators
Authors: Chen Xianfeng , Ammu Satya K. , Masania Kunal , Steeneken Peter G. , Alijani Farbod
Published: October 2022

Levitation offers extreme isolation of mechanical systems from their environment, while enabling unconstrained high‐precision translation and rotation of objects. Diamagnetic levitation is one of the most attractive levitation schemes because it allows stable levitation at room temperature without the need for a continuous power supply. However, dissipation by eddy currents in conventional diamagnetic materials significantly limits the application potential of diamagnetically levitating systems. Here, a route toward high‐Q macroscopic levitating resonators by substantially reducing eddy current damping using graphite particle based diamagnetic composites is presented. Resonators that feature quality factors Q above 450 000 and vibration lifetimes beyond one hour are demonstrated, while levitating above permanent magnets in high vacuum at room temperature. The composite resonators have a Q that is >400 times higher than that of diamagnetic graphite plates. By tuning the composite particle size and density, the dissipation reduction mechanism is investigated, and the Q of the levitating resonators is enhanced. Since their estimated acceleration noise is as low as some of the best superconducting levitating accelerometers at cryogenic temperatures, the high Q and large mass of the presented composite resonators positions them as one of the most promising technologies for next generation ultra‐sensitive room temperature accelerometers.
Permeability‐Engineered Compartmentalization Enables In Vitro Reconstitution of Sustained Synthetic Biology Systems
Authors: Li Luyao , Zhang Rong , Chen Long , Tian Xintong , Li Ting , Pu Bingchun , Ma Conghui , Ji Xiangyang , Ba Fang , Xiong Chenwei , Shi Yunfeng , Mi Xianqiang , Li Jian , Keasling Jay D. , Zhang Jingwei , Liu Yifan
Published: October 2022

In nature, biological compartments such as cells rely on dynamically controlled permeability for matter exchange and complex cellular activities. Likewise, the ability to engineer compartment permeability is crucial for in vitro systems to gain sustainability, robustness, and complexity. However, rendering in vitro compartments such a capability is challenging. Here, a facile strategy is presented to build permeability‐configurable compartments, and marked advantages of such compartmentalization are shown in reconstituting sustained synthetic biology systems in vitro. Through microfluidics, the strategy produces micrometer‐sized layered microgels whose shell layer serves as a sieving structure for biomolecules and particles. In this configuration, the transport of DNAs, proteins, and bacteriophages across the compartments can be controlled an guided by a physical model. Through permeability engineering, a compartmentalized cell‐free protein synthesis system sustains multicycle protein production; ≈100 000 compartments are repeatedly used in a five‐cycle synthesis, featuring a yield of 2.2 mg mL−1. Further, the engineered bacteria‐enclosing compartments possess near‐perfect phage resistance and enhanced environmental fitness. In a complex river silt environment, compartmentalized whole‐cell biosensors show maintained activity throughout the 32 h pollutant monitoring. It is anticipated that permeability‐engineered compartmentalization should pave the way for practical synthetic biology applications such as green bioproduction, environmental sensing, and bacteria‐based therapeutics.
Unveiling Local Electronic Structure of Lanthanide‐Doped Cs2NaInCl6 Double Perovskites for Realizing Efficient Near‐Infrared Luminescence
Authors: Han Siyuan , Tu Datao , Xie Zhi , Zhang Yunqin , Li Jiayao , Pei Yifan , Xu Jin , Gong Zhongliang , Chen Xueyuan
Published: October 2022

Lanthanide ion (Ln3+)‐doped halide double perovskites (DPs) have evoked tremendous interest due to their unique optical properties. However, Ln3+ ions in these DPs still suffer from weak emissions due to their parity‐forbidden 4f–4f electronic transitions. Herein, the local electronic structure of Ln3+‐doped Cs2NaInCl6 DPs is unveiled. Benefiting from the localized electrons of [YbCl6]3− octahedron in Cs2NaInCl6 DPs, an efficient strategy of Cl−‐Yb3+ charge transfer sensitization is proposed to obtain intense near‐infrared (NIR) luminescence of Ln3+. NIR photoluminescence (PL) quantum yield (QY) up to 39.4% of Yb3+ in Cs2NaInCl6 is achieved, which is more than three orders of magnitude higher than that (0.1%) in the well‐established Cs2AgInCl6 via conventional self‐trapped excitons sensitization. Density functional theory calculation and Bader charge analysis indicate that the [YbCl6]3− octahedron is strongly localized in Cs2NaInCl6:Yb3+, which facilitates the Cl−‐Yb3+ charge transfer process. The Cl−‐Yb3+ charge transfer sensitization mechanism in Cs2NaInCl6:Yb3+ is further verified by temperature‐dependent steady‐state and transient PL spectra. Furthermore, efficient NIR emission of Er3+ with the NIR PLQY of 7.9% via the Cl−‐Yb3+ charge transfer sensitization is realized. These findings provide fundamental insights into the optical manipulation of Ln3+‐doped halide DPs, thus laying a foundation for the future design of efficient NIR‐emitting DPs.
Cation Defect Engineering of Transition Metal Electrocatalysts for Oxygen Evolution Reaction
Authors: Yan Dafeng , Xia Chenfeng , Zhang Wenjing , Hu Qi , He Chuanxin , Xia Bao Yu , Wang Shuangyin
Published: October 2022

The rational design and development of highly efficient oxygen evolution reaction (OER) electrocatalysts is vital for the application of renewable energy devices. Recently, the strategy of defect engineering draws much attention due to its positive effect on regulating the electronic structure, and thus, promoting the electrocatalytic performance of various materials. In this review, the main focus is on the cation vacancy defects of transition metal‐based electrocatalysts; the latest progress in cation vacancy defect engineering for the electrocatalytic OER is summarized. The different effects of cation vacancy defects on OER are well discussed together with the reaction mechanism, mainly including improving the conductivity, optimizing the adsorption of key intermediates, guiding the surface reconstruction to form active species, and enhancing the long‐term stability. Then, methods to construct cation vacancy defects on different electrocatalysts and the characterization of cation vacancies are systematically introduced. Finally, the remaining challenges and future prospects of cation vacancy defect engineering for promoting OER performance are further proposed.
Synthesis of Sumanene‐fused Acenes
Authors: Nakazawa Hironobu , Ohya Akinobu , Morimoto Yuto , Uetake Yuta , Ikuma Naohiko , Okada Kenji , Nakano Masayoshi , Yakiyama Yumi , Sakurai Hidehiro
Published: October 2022

Sumanene derivatives fused by quinones and acenes were synthesized through Friedel‐Crafts double acylation, followed by reductive aromatization. Single‐crystal X‐ray diffraction analysis on synthesized quinone and acene derivatives revealed the one‐dimensional (1D) columnar stackings predominated by the concave‐convex alignment from sumanene moiety. The thus‐prepared sumanene‐fused acenes exhibited higher solubility to organic solvent and significant stability against aerobic oxidation than the pristine acenes.
Pneumomediastinum as patient self‐inflicted lung injury in patients with acute respiratory distress syndrome due to COVID‐19: a case series
Authors: Watanabe Rika , Nakayama Ryuichi , Bunya Naofumi , Yama Naoya , Iwamoto Yusuke , Katayama Yoichi , Kasai Takehiko , Sawamoto Keigo , Uemura Shuji , Narimatsu Eichi
Published: October 2022

Background

In patients with coronavirus disease (COVID‐19) due to severe acute respiratory syndrome coronavirus 2 infection, pneumomediastinum has been increasingly reported in cases of noninvasive oxygen therapy, including high‐flow nasal cannula, and invasive mechanical ventilation. However, its pathogenesis is still not understood.

Case Presentation

We report two cases of pneumomediastinum in acute respiratory distress syndrome (ARDS) caused by COVID‐19. In both cases, control of spontaneous breathing with neuromuscular blocking agents resulted in resolution of pneumoperitoneum.

Conclusion

The improvement of pneumomediastinum with control of spontaneous breathing suggested patient self‐inflicted lung injury as a possible mechanism in this case series. In ARDS cases with pneumomediastinum, in addition to controlling plateau pressure with conventional lung protective ventilation, spontaneous breathing should be controlled if the patient’s inspiratory effort is suspected to be strong.