bluuebunny/crossref_metadata_2025_split huggingface dataset:
Natural Product Synthesis by Rhodium and Ruthenium‐Catalyzed CH Activation
Authors: Dethe Dattatraya H. , Beeralingappa Nagabhushana C. , Koley Suprotim 
Published: October 2022

Abstract
Rhodium‐catalyzed CH activation has attracted significant attention among the synthetic community due to high catalytic reactivity, stability, selectivity, and decent functional group compatibility. The utility of rhodium‐catalyzed CH activation in the field of total synthesis has become an alternative and efficient strategy to the traditional synthetic methods. The application of site‐selective synthetic methodologies using rhodium catalysis has set the stage for innovative retrosynthetic disconnections and provides rapid access to various natural products for drug discovery and chemical biology. Various rhodium‐based catalytic systems showed their remarkable reactivity potential for CH functionalization reactions and their applications in the total synthesis of natural products are well documented. In this article, recent progress in the Rh‐catalyzed CH activation for the efficient synthesis of various bioactive natural products has been reviewed, and also the application of a few Ru‐catalyzed CH activation for total syntheses and Co‐catalyzed CH activation for late‐stage functionalization of biologically active compounds and natural products has been included.
Ag‐Catalyzed/Mediated CX Bond Formation (X = P, S, Se) Through CH Bond Functionalization
Authors: Barcellos Angelita M. , da Costa Gabriel P. , Lenardão Eder João , Silva Márcio S. , Alves Diego 
Published: October 2022

AbstractConsidering the chemical and biological interest in compounds that contain Se, S, and P atoms in their structure, as well as the increasing number of protocols using silver as catalyst or promoter in CH functionalization reactions in the past decade, this article describes the significant advances on using this metal in the formation of new CS, CSe, and CP bonds. It starts with a discussion on the general reactivity of silver species as catalyst in chalcogenylation and phosphorylation protocols. It was highlighted in detail the proposed mechanisms for these recently disclosed methods. Additionally, procedures using silver salts as a promoter agent (one or more equivalent of Ag) also were presented. This article summarizes the recent advances in highly regioselective methods to CS, CSe, and CP bond formations by the CH functionalization of several substrates, such as alkenes, terminal alkynes, and a wide range of heterocycles.
Hydrogen Bond‐Accelerated Meta‐Selective CH Functionalization with Iridium
Authors: Kuninobu Yoichiro 
Published: October 2022

Abstract
This article summarizes the design of the catalytic systems and regioselective CH borylation of (hetero)aromatic compounds using the noncovalent interactions, such as hydrogen bonding and Lewis acid–base interaction, between the substrate recognition part of the ligand of catalysts and the functional group of substrates. Formal meta‐selective introduction of a variety of functional groups into (hetero)aromatic compounds based on the meta‐selective CH borylation is explained. In addition, acceleration of the reaction and expression of functional group and substrate specificities are introduced. In the summary section, recently reported reactions using the noncovalent interaction method and the several reviews and accounts are cited.
CH Activation of Indolines, Tetrahydroquinolines, and Tetrahydroisoquinolines
Authors: Kowalczyk Rafał , Dajek Maciej 
Published: October 2022

Abstract

Indolines could be successfully applied in the diversity of CH bond functionalization of benzenoid moiety without the competition between sp
3
H and sp
2
H activations thereby offering an access to functionalized heterocycles including the indoles. The metal‐catalyzed transformations proceeding the CH functionalizations of C4, C5, C6, and C7 position will be covered in the article along with applications to analogs systems in tetrahydroquinolines and tetrahydroisoquinolines.
Cobalt Catalyzed CH Amination and Amidation
Authors: Sk Md Raja , Saha Shuvendu , Maji Modhu Sudan 
Published: October 2022

AbstractLooking into the increasing requirement for sustainable and environmentally sound chemical processes, employing nonprecious metals, specifically the earth‐abundant ones, is an attractive choice to construct CN bond by CH activation strategy involving the inner‐ or outer‐sphere mechanism. The article described Co(II)–porphyrins and cyclopentadienyl‐ligand‐based catalysts as the new class of effective catalysts for the amination or amidation of C(sp2/sp3)H bonds, with prominence to access a wide array of nitrogen‐containing compounds including heterocycles, natural products, medicinally significant bioactive molecules, and synthetic intermediates.
Nickel‐Catalyzed Asymmetric CH Functionalization
Authors: Wang Rong‐Hua , Ye Mengchun 
Published: October 2022

Abstract

Due to its unique nature and distinctive reactivity, nickel has been widely used as catalyst in CH bond functionalization. However, enantioselective versions have been faced with great challenge owing to the lack of efficient chiral ligands. With the emergence of new types of chiral ligands such as bifunctional phosphine oxides and bulky
N
‐heterocyclic carbenes (NHC) bearing chiral pendants, substantial progress has been achieved in recent years. Herein, we summarize recent advances of this burgeoning field.
Rhodium‐ and Iridium‐Catalyzed Benzylic CH Functionalization
Authors: Manisha XXXXXXX , Sharma Upendra 
Published: October 2022

Abstract

Traditionally, most of the CH bonds were considered chemically inert, and mainly, prefunctionalized substrates were employed for further transformations. But in the past three decades, CH functionalization has emerged as an efficient strategy to streamline the synthesis of complex target molecules without using prefunctionalized substrates. Recent advances in transition metal catalysis have enabled access to benzylic C(sp
3
)H bond functionalization with good regioselectivity. Apart from different transition metals utilized for C(sp
3
)H functionalization, rhodium‐ and iridium‐based catalysts are widely explored due to their appreciable reactivity and selectivity. This article sketches the recent progress in benzylic CH functionalization through rhodium and iridium catalysis. The mechanistic details of some reactions have been included to understand this developing field in the CH functionalization era.
Enantioselective Functionalization of Inert C(sp
3
)H Bonds by Photochemistry
Authors: Xiaokai Cheng , Zhan Lu 
Published: October 2022

Abstract
The selective functionalization of inert CH bonds is regarded as one of the most attractive research field due to the advantages of expanding diversity, reducing waste and synthetic economy in modifying organic compounds. However, because of the high bond energy, similar bond strengths and steric environments, the CH bond functionalization meets the challenge of controlling the regio‐ and stereoselectivity. Due to the efficient electron transfer and energy transfer, the photocatalysis could provide an accessible alternative for the regioselective functionalization of inert CH bonds. In recent years, the enantioselective functionalization of inert CH bonds by photochemistry has been developed. This article summarized this field as photocatalysis with three main strategies: transition‐metal catalysis, chiral Lewis acid catalysis, and chiral organocatalysis.
Outer‐Sphere CH Bond Activation
Authors: Singh Sanjay , Hazra Chinmoy K. 
Published: October 2022

AbstractTransition metal‐catalyzed reactions that are capable of C(sp3)H bond functionalization by allowing readily available starting materials and providing novel synthetic disconnection have become a keystone in modern organic synthetic transformation. Outer‐sphere catalysis, the CH activation reaction, has attracted interest in organic synthesis. In this article, we have discussed the advancement in the field of C(sp3)H bond functionalization reactions, with an emphasis on their utility to construct biologically active molecules and synthesis of natural products via outer‐sphere catalysis. Here, we discussed mainly on CN/CO/CC bond formation catalyzed through direct CH bond functionalization using nonprecious transition metal complexes. These synthetic transformations were achieved by C(sp3)H insertion of a metallonitrene that proceeds via either a concerted asynchronous process or a stepwise radical pathway. The aim of this article is to deliver valuable information and guidance for the use of unactivated CH bond functionalization reactions and provide important synthetic tool to inspire future research in this area.
First‐Row Transition Metals (Mn, Fe, Co, Ni, Cu)‐Catalyzed CH Bond Functionalization Through Weak Chelation
Authors: Banjare Shyam K. , Pati Bedadyuti V. , Ravikumar Ponneri C. 
Published: October 2022

Abstract

The transition metal‐catalyzed CH bond functionalization strategy has opened up a wide range of opportunities to develop organic transformations in a step‐ and atom‐economical manner. The use of earth‐abundant 3d transition metals further translates these transformations into a cost‐effective as well as eco‐friendly approach. The selective CH bond activation could be achieved by utilizing the proximal directing group present in a molecule. In this regard, strongly chelating
N
‐directing groups (8‐aminoquinoline, pyrimidine, and pyridine) were well explored; however, the use of readily available and weakly coordinating
O
‐directing groups (aldehyde, ketone, and ester) is underdeveloped. Thus, synthetic transformations that utilize earth‐abundant 3d transition metal catalysts along with easily available weakly coordinating directing groups are highly sustainable, especially for the large‐scale production of chemicals in industries. This article has been devoted for a detailed discussion on CH bond functionalization, assisted by first‐row transition metal catalysts (Mn, Fe, Co, Ni, Cu) through weak coordination.
Synthesis of Peptide Macrocycle via Metal‐Catalyzed CH Macrocyclization
Authors: Bazzi Sakna , Messaoudi Samir 
Published: October 2022

Abstract

Transition‐metal‐catalyzed CH activation has emerged as a powerful macrocyclization tool with relevant applications in peptide drug discovery. This approach which exploits unactivated CH bonds as nontraditional “handle” for CC bond cyclization, has facilitated the chemical creation of new macrocyclic peptide topologies. In this article, we highlight the different established strategies for C(sp
2
)H and C(sp
3
)H functionalization to access macrocyclic peptides in which chemo‐ and regioselectivies were discussed. We consider that many exciting applications will emerge by applying the CH activation approach to synthesize new macrocyclic topologies or rationally designed bioactive macrocyclic peptides.
Harvesting Electrical Energy from High Temperature Environment by Aerogel Nano‐Covered Triboelectric Yarns
Authors: Xing Fangjing , Ou Zhiqiang , Gao Xiaobo , Chen Baodong , Wang Zhong Lin 
Published: October 2022

AbstractIntegrating power into fabrics offers exciting opportunities for wearable technologies, which has long remained challenging to make flexible, high temperature resistant textile‐based powers. Here, an all yarns‐based triboelectric nanogenerator (Y‐TENG) is proposed to harvest electrical energy and sense biological motion for temperatures between 25 and 400 °C, the upper limit of temperature is greatly improved. The Y‐TENG is capable of outputting a transferred charge density of 30 nC cm−2, the external load resistance is 180 MΩ, and the peak power reaches 0.17 mW, and the average response time is lower than 15 ms. Based on a simple processing strategy, when introducing silica aerogel during electrospinning of polyimide nano‐covered layer to make multi‐ply and stabilized triboelectric yarns. Unlike ordinary fibers and yarns, the core‐shell structured design also shows a high sensitivity to all kinds of mechanical triggering sources. Furthermore, a self‐powered movement characteristic monitoring system by coordinating smart protective suit is further developed to provide real‐time sensing and rescuing assistance. This aerogel nano‐covered triboelectric yarn has great application prospects for energy generation and motion detection in high‐temperature and many other high‐risk environments.
Enabling Conversion‐Type Iron Fluoride Cathode by Halide‐Based Solid Electrolyte
Authors: Shao Bowen , Tan Sha , Huang Yonglin , Zhang Lifu , Shi Jian , Yang Xiao‐Qing , Hu Enyuan , Han Fudong 
Published: October 2022

AbstractThe practical application of low‐cost and energy‐dense iron fluoride cathodes is hindered by the first cycle electrochemical irreversibility, cycling instability, and large voltage hysteresis. Here, it is reported that these challenges may be overcome by the utilization of halide‐based solid electrolytes (SEs). The excellent electrochemical stability of halide‐based SEs enables a complete conversion and deconversion of FeF2 that cannot be achieved with sulfide‐based SEs. Due to restricted and reversible decomposition of SE, prevention of Fe dissolution, mechanical confinement of active material, as well as improved electrode kinetics, solid‐state FeF2 cathode with halide‐based SE demonstrates superior electrochemical performance compared with FeF2 electrodes in liquid electrolytes, with a high 1st cycle coulombic efficiency (≈100%), high specific capacity (≈600 mAh g−1), long cycle life (>100 cycles), and high‐rate performance (up to 2 C). The results suggest solidifying the batteries is a viable approach to addressing the long‐standing key challenges of iron fluoride cathodes.
Topological Nanofibers Enhanced Piezoelectric Membranes for Soft Bioelectronics
Authors: Lan Boling , Xiao Xiao , Carlo Aiden Di , Deng Weili , Yang Tao , Jin Long , Tian Guo , Ao Yong , Yang Weiqing , Chen Jun 
Published: October 2022

AbstractElectrospun piezoelectric membranes are compelling building blocks for constructing wearable bioelectronics. However, the efficiency of electromechanical conversion over a wide bandwidth is still insufficient due to the restriction between fiber dipole alignment and energy absorption. Topology optimization is a mathematical method that lets us optimize the layout of a system to maximize its performance given a set of boundary conditions and constraints. Here, topological designs as a reinforcement mechanism are developed to enhance the electromechanical response of electrospun piezoelectric membranes. The topologically optimized membranes show a 300% increase in electric output and a 478% increase in frequency response range compared with traditional electrospun membranes. With the optimized piezoelectric membrane design, the developed textile acoustic sensors can capture the human voice for speech recognition with a classification accuracy of up to 100% with the help of deep learning. Because of the universality and superiority of this new topologically optimal design, it represents a milestone in designing electrospun membranes for electromechanical conversion and high‐performance soft bioelectronics.
A Unified Understanding of Diverse Spin Textures of Kramers–Weyl Fermions in Nonmagnetic Chiral Crystals
Authors: Tan Wei , Jiang Xiao , Li Yang , Wu Xiaoqiang , Wang Jianfeng , Huang Bing 
Published: October 2022

AbstractChiral crystals, characterized by rotation, screw rotation, and translation symmetries are abundant in nature. The existence of Kramers–Weyl fermions (KWFs) at the time‐reversal‐invariant momenta in nonmagnetic chiral crystals (NCCs) has attracted intense attention due to their unique physical properties beyond conventional Weyl fermions. Although the spin texture, one of the most fundamental physical quantities, is found to be dramatically different for different KWFs in different NCCs, a unified understanding of this puzzling phenomenon is still lacking. In this article, combining k · p theory and first‐principles calculations, k‐linear Hamiltonians for KWFs are constructed and consequently a complete classification for the spin textures of KWFs in all the NCCs is made, which are confirmed by a series of material example calculations. Interestingly, it is found that the spin textures are reversed in NCCs with opposite chirality, leading to reversed Fermi arc surface states. Importantly, this study unveils that the nonlinear optical responses around the KWFs in NCCs can be largely determined by their spin texture classification. This study not only provides a unified understanding of the spin textures of KWFs in all the NCCs, but also suggests a principle to design novel KWF‐related spintronics and nonlinear optics.
Deep‐Learning‐Assisted Noncontact Gesture‐Recognition System for Touchless Human‐Machine Interfaces
Authors: Zhou Hao , Huang Wei , Xiao Zhuo , Zhang Shichuan , Li Wangzhan , Hu Jinhui , Feng Tianxing , Wu Jing , Zhu Pengcheng , Mao Yanchao 
Published: October 2022

AbstractHuman‐machine interfaces (HMIs) play important role in the communication between humans and robots. Touchless HMIs with high hand dexterity and hygiene hold great promise in medical applications, especially during the pandemic of coronavirus disease 2019 (COVID‐19) to reduce the spread of virus. However, current touchless HMIs are mainly restricted by limited types of gesture recognition, the requirement of wearing accessories, complex sensing platforms, light conditions, and low recognition accuracy, obstructing their practical applications. Here, an intelligent noncontact gesture‐recognition system is presented through the integration of a triboelectric touchless sensor (TTS) and deep learning technology. Combined with a deep‐learning‐based multilayer perceptron neural network, the TTS can recognize 16 different types of gestures with a high average accuracy of 96.5%. The intelligent noncontact gesture‐recognition system is further applied to control a robot for collecting throat swabs in a noncontact mode. Compared with present touchless HMIs, the proposed system can recognize diverse complex gestures by utilizing charges naturally carried on human fingers without the need of wearing accessories, complicated device structures, adequate light conditions, and achieves high recognition accuracy. This system could provide exciting opportunities to develop a new generation of touchless medical equipment, as well as touchless public facilities, smart robots, virtual reality, metaverse, etc.
Multifunctional 1D Nanostructures toward Future Batteries: A Comprehensive Review
Authors: Cheong Jun Young , Cho Su‐Ho , Lee Jiyoung , Jung Ji‐Won , Kim Chanhoon , Kim Il‐Doo 
Published: October 2022

AbstractDue to the unique properties which are considerably different from macro‐scale or bulk materials, 1D) nanostructures have received great interests. In particular, they have greatly contributed to building next‐generation batteries by providing beneficial features such as short ion/electron pathways, structural versatility (i.e., formation of 3D current collectors, free‐standing electrodes, and separators), and excellent stress relaxation. Owing to these definite advantages, 1D nanostructure is often followed by discovery of new electrode materials. This review provides a systematic overview of the state‐of‐the‐art research progresses on 1D nanostructures, which are extensively used for rechargeable batteries. Specifically, a brief introduction of some important 1D nanostructuring methods is started and then, in situ structural characterizations using 1D nanostructures are summarized, which allow a great step forward in atomic‐scale monitoring of reaction kinetics and observing dynamic structural evolution of electrode materials. 1D nanstructuring in solid‐state electrolytes and stabilization of metal anodes are also highlighted which are not only substantially important in current research trends for future batteries but also rarely discussed in previous reviews. At the end, critical perspective and future research direction of 1D nanoengineering for future batteries are suggested.
Multicomponent System of Single‐Walled Carbon Nanotubes Functionalized with a Melanin‐Inspired Material for Optical Detection and Scavenging of Metals
Authors: Wulf Verena , Bichachi Ella , Hendler‐Neumark Adi , Massarano Tlalit , Leshem Avigail Baruch , Lampel Ayala , Bisker Gili 
Published: October 2022

AbstractThe accumulation of metal ions in organisms and the presence of heavy metals in water cause adverse effects on ecosystems and results in numerous human health issues such as cancer and neurogenerative diseases. Therefore, the development of novel platforms for metal‐scavenging and rapid metal detection for in situ applications are of high importance. Here, this challenge is tackled by taking advantage of the metal chelation ability of a melanin‐inspired material in combination with the near‐infrared (NIR) fluorescence response of single‐walled carbon nanotubes (SWCNTs) to surface binding. SWCNTs are functionalized by a melanin‐like substance, obtained by enzymatic oxidative polymerization of a fluorenylmethyloxycarbonyl‐tyrosine (FmocY) precursor. The resulting multicomponent system (SWCNT‐FmocYOx) serves as a metal‐ion scavenging platform that concurrently reports on metal binding with optical signal transduction. Upon binding of a library of mostly divalent transition metal‐ions, the fluorescence emission of the functionalized SWCNTs is modulated, showing a concentration‐dependent response with a limit of detection in the nanomolar range. Metal‐binding and removal from water of up to 98% is further shown via inductively coupled plasma mass spectrometry. The SWCNT‐FmocYOx hybrid system presents a novel platform with NIR optical signal for real‐time feedback on metal‐ion scavenging.
A Novel Self‐Assembled Cobalt‐Free Perovskite Composite Cathode with Triple‐Conduction for Intermediate Proton‐Conducting Solid Oxide Fuel Cells
Authors: Tong Hua , Fu Min , Yang Yang , Chen Fanglin , Tao Zetian 
Published: October 2022

AbstractA traditional composite cathode for proton‐conducting solid oxide fuel cells (H‐SOFCs) is typically obtained by mixing cathode materials and proton conducting electrolyte of BaCe0.7Y0.2Zr0.1O3–δ (BZCY), providing chemical and thermal compatibility with the electrolyte. Here, a series of triple‐conducing and cobalt‐free iron‐based perovskites as cathodes for H‐SOFCs is reported. Specifically, BaCexFe1–xO3–δ (x = 0.36, 0.43, and 0.50) shows various contents of two single phase perovskites with an in situ heterojunction structure as well as triple conductivity by tailoring the Ce/Fe ratios. The cell performance with the optimized BaCe0.36Fe0.64O3–δ (BCF36) cathode composition reaches 1056 mW cm−2 at 700 °C. Moreover, a record cell performance of 1525 mW cm−2 at 700 °C is obtained by modifying the BCF36 cathode microstructure through a spraying method, demonstrating high promise with Co‐free cathodes for H‐SOFCs.