The highly integrated and miniaturized next-generation electronic products call for high-performance electromagnetic interference(EMI)shielding materials to assure the normal operation of their closely assembled compo...The highly integrated and miniaturized next-generation electronic products call for high-performance electromagnetic interference(EMI)shielding materials to assure the normal operation of their closely assembled components.However,the most current techniques are not adequate for the fabrication of shielding materials with programmable structure and controllable shielding efficiency.Herein,we demonstrate the direct ink writing of robust and highly conductive Ti3C2Tx MXene frames with customizable structures by using MXene/AlOOH inks for tunable EMI shielding and electromagnetic wave-induced thermochromism applications.The as-printed frames are reinforced by immersing in AlCl_(3)/HCl solution to remove the electrically insulating AlOOH nanoparticles,as well as cross-link the MXene sheets and fuse the filament interfaces with aluminum ions.After freeze-drying,the resultant robust and porous MXene frames exhibit tunable EMI shielding efficiencies in the range of 25-80 dB with the highest electrical conductivity of 5323 S m−1.Furthermore,an electromagnetic wave-induced thermochromic MXene pattern is assembled by coating and curing with thermochromic polydimethylsiloxane on a printed MXene pattern,and its color can be changed from blue to red under the high-intensity electromagnetic irradiation.This work demonstrates a direct ink printing of customizable EMI frames and patterns for tuning EMI shielding efficiency and visualizing electromagnetic waves.展开更多
Multimedia big data brings tremendous challenges as well as opportunities for multimedia applications/services. In this paper, we present a survey and tutorial for multimedia big data. After discussing the characteris...Multimedia big data brings tremendous challenges as well as opportunities for multimedia applications/services. In this paper, we present a survey and tutorial for multimedia big data. After discussing the characteristics of multimedia big data such as human-centricity, multimodality, heterogeneity, unprecedented volume, and so on, this paper provides an overview of the state-of-the-art of multimedia big data, reviews the latest related technologies, and discusses the technical challenges. We conclude this paper with a discussion of open problems and future directions.展开更多
Controlling energy expenditure during acute cold exposure is a fundamental aspect of metabolic dynamics in organisms.However,prior studies on cold-induced thermogenesis faced limitations,primarily focusing on brown ad...Controlling energy expenditure during acute cold exposure is a fundamental aspect of metabolic dynamics in organisms.However,prior studies on cold-induced thermogenesis faced limitations,primarily focusing on brown adipose tissue(BAT)and lacking precise in vivo flux measurements.This editorial aims to highlight the recent research by Bornstein et al.providing a comprehensive and quantitative insight into the intricate alterations in metabolic flux that drive this phenomenon[1].展开更多
Strain-release ring-opening trifluoromethylthiolation to construct SCF3-substituted cyclic motifs was under-explored,and di-trifluoromethylthiolation is unachieved.Herein,we present the first trifluoromethylthiolation...Strain-release ring-opening trifluoromethylthiolation to construct SCF3-substituted cyclic motifs was under-explored,and di-trifluoromethylthiolation is unachieved.Herein,we present the first trifluoromethylthiolation of bicyclo[1.1.0]butane(BCB)and bicyclo[2.1.0]pentane.By employing different activators,both mono-and di-trifluoromethylthio substituted cyclobutane and cyclopentane derivatives were successfully obtained.展开更多
The trifluoromethoxy group(OCF_(3))has garnered significant attention and exhibited unique characteristics in the realms of life sciences,pharmaceuticals,and agrochemicals.The development of efficient methods for synt...The trifluoromethoxy group(OCF_(3))has garnered significant attention and exhibited unique characteristics in the realms of life sciences,pharmaceuticals,and agrochemicals.The development of efficient methods for synthesizing diverse trifluoromethoxy molecules is therefore of paramount importance.However,due to the weak nucleophilicity and instability of the OCF_(3)group,many catalysts have shown limited applicability in OCF_(3)compound synthesis.Encouragingly,silver catalysts have emerged as notable contenders and have effectively facilitated the synthesis of a variety of alkyl,aromatic and alkenyl OCF_(3)products through direct trifluoromethoxylation and indirect methods.This review aims to provide a comprehensive overview of silvermediated/catalyzed reactions for the synthesis of trifluoromethoxy molecules,focusing particularly on the roles of silver and the reaction mechanisms.展开更多
The trifluoromethoxy(CF_3O) group has become a novel moiety in various fields because of its unique features. However, despite the promising applications, the synthesis of CF_3O-containing compounds is still a challen...The trifluoromethoxy(CF_3O) group has become a novel moiety in various fields because of its unique features. However, despite the promising applications, the synthesis of CF_3O-containing compounds is still a challenge due to indirect synthetical strategies and volatile reagent which is hard to handle. Until very recently, several innovative reagents were developed to facilitate the trifluoromethoxylation reaction and make CF_3O-containing compounds more accessible. This review mainly focuses on the recent advances in new trifluoromethoxylation reagents and their usage.展开更多
Comprehensive Summary,The trifluoromethoxy functional group has received increasing attention in recent years due to its distinctive properties such as good metabolic stability,appropriate lipophilicity and special el...Comprehensive Summary,The trifluoromethoxy functional group has received increasing attention in recent years due to its distinctive properties such as good metabolic stability,appropriate lipophilicity and special electrical properties.Thus,the development of new reagents and new strategies of direct trifluoromethoxylation are attracting the enthusiasm of many fluorine chemical workers.At present,nucleophilic and radical trifluoromethoxylating reagents have made major breakthroughs,greatly promoting the development of trifluoromethoxy chemistry.展开更多
The development of synthetic methods for the introduction of the fluorine atom and fluoroalklyl groups into organic molecules has gained increased attention.Synthetic organic chemists have recently jumped into the fie...The development of synthetic methods for the introduction of the fluorine atom and fluoroalklyl groups into organic molecules has gained increased attention.Synthetic organic chemists have recently jumped into the field of organofluorine chemistry and have thus made significant contributions.Furthermore,these newly developed methods are typically safer and more effective than the traditional methods.In this review,wewill summarize the representative contributions of new reagents and reactions developed in the past decade.展开更多
The OCF_(3)group has good metabolic stability,suitable lipophilicity and special electrical properties,which can modify the properties of drugs and material molecules.In recent years,trifluoromethoxy compounds have re...The OCF_(3)group has good metabolic stability,suitable lipophilicity and special electrical properties,which can modify the properties of drugs and material molecules.In recent years,trifluoromethoxy compounds have received more and more attention.Both new reagents and new trifluoromethoxylation strategies got a breakthrough.Our group has been committed to the development of trifluoromethoxylation reagents and methods.This account focuses on describing various trifluoromethoxylation reactions with trifluoromethyl sulfonates(TFMS)and(E)-O-trifluoromethyl-benzaldoximes(TFBO)developed by our group.展开更多
A radical-mediated method was reported for diastereoselective synthesis of non-classical heteroaryl C-glycosides via Minisci-type alkylation of N-heteroarenes with 4-glycosyl-1,4-dihydropyridine(DHP)reagents.These DHP...A radical-mediated method was reported for diastereoselective synthesis of non-classical heteroaryl C-glycosides via Minisci-type alkylation of N-heteroarenes with 4-glycosyl-1,4-dihydropyridine(DHP)reagents.These DHP reagents serve as convenient precursors for various glycosyl radicals under the activation of single electron transfer(SET)oxidation by persulfate and visible light irradiation with or without photocatalyst.展开更多
In recent years,the trifluoromethoxy(OCF3)functional group has received extensive attention in phar-maceuticals,agrochemicals and material sciences.However,the methods for the enantioselective syn-thesis of trifluorom...In recent years,the trifluoromethoxy(OCF3)functional group has received extensive attention in phar-maceuticals,agrochemicals and material sciences.However,the methods for the enantioselective syn-thesis of trifluoromethoxylated stereogenic carbon centers are rare owing to the nature of easy decom-position of OCF3 anion and limited OCF3 reagent.And the asymmetric trifluoromethoxylation will be a hot research topic in near future due to the unique biological properties of a single isomer.This article mainly focuses on the recent advances in the enantioselectiveconstruction of trifluoromethoxylated stereogenic carbon centers.展开更多
Summary of main observation and conclusion Schisandraceae triterpenoids are novel natural products that contain highly fused ring systems bearing multiple chiral centers surrounding. Some of them exhibit promising bio...Summary of main observation and conclusion Schisandraceae triterpenoids are novel natural products that contain highly fused ring systems bearing multiple chiral centers surrounding. Some of them exhibit promising bioactivities, such as antitumor, anti‐HIV, etc. In this article, we describe our efforts to the collective total synthesis of schilancidilactones A, B, schilancitrilactones A, B, C, and 20‐epi‐schilancitrilactone A from common precursors. An intramolecular radical cyclization, late‐stage halogenation and AIBN‐mediated or Ni‐catalyzed intermolecular radical cross coupling reaction were employed as the key steps.展开更多
Natural products have been identified as one of the most important source for new drug discovery. Among them, we focused on the highly oxygenated natural products due to their important biological activity and diversi...Natural products have been identified as one of the most important source for new drug discovery. Among them, we focused on the highly oxygenated natural products due to their important biological activity and diversity structures.展开更多
A rhodium/diene catalyzed asymmetric allylic trifluoromethoxylation reaction is reported,which afforded chiral trifluoromethoxylated allylic compounds in 52%–97%yields with up to 97%enantiomeric excess.These are the ...A rhodium/diene catalyzed asymmetric allylic trifluoromethoxylation reaction is reported,which afforded chiral trifluoromethoxylated allylic compounds in 52%–97%yields with up to 97%enantiomeric excess.These are the first examples of asymmetric allylic trifluoromethoxylation.The reactions proceed via a dynamic kinetic process that allowed for the use of racemic allylic trichloroacetimidates as substrates.Density functional theory calculations showed that the formation of the C–OCF_(3)bond occurs via outer-sphere nucleophilic attack.Importantly,the presence of the allylic group in the products enabled them to be converted into a diverse array of optically active trifluoromethylated molecules that are otherwise difficult to access.展开更多
基金support from the National Natural Science Foundation of China(51922020,52090034)the Fundamental Research Funds for the Central Universities(BHYC1707B)。
文摘The highly integrated and miniaturized next-generation electronic products call for high-performance electromagnetic interference(EMI)shielding materials to assure the normal operation of their closely assembled components.However,the most current techniques are not adequate for the fabrication of shielding materials with programmable structure and controllable shielding efficiency.Herein,we demonstrate the direct ink writing of robust and highly conductive Ti3C2Tx MXene frames with customizable structures by using MXene/AlOOH inks for tunable EMI shielding and electromagnetic wave-induced thermochromism applications.The as-printed frames are reinforced by immersing in AlCl_(3)/HCl solution to remove the electrically insulating AlOOH nanoparticles,as well as cross-link the MXene sheets and fuse the filament interfaces with aluminum ions.After freeze-drying,the resultant robust and porous MXene frames exhibit tunable EMI shielding efficiencies in the range of 25-80 dB with the highest electrical conductivity of 5323 S m−1.Furthermore,an electromagnetic wave-induced thermochromic MXene pattern is assembled by coating and curing with thermochromic polydimethylsiloxane on a printed MXene pattern,and its color can be changed from blue to red under the high-intensity electromagnetic irradiation.This work demonstrates a direct ink printing of customizable EMI frames and patterns for tuning EMI shielding efficiency and visualizing electromagnetic waves.
基金supported in part by the Na tional Natural Science Foundation of China (NO. 61401004, 61271233, 60972038)Plan of introduction and cultivation of university leading talents in Anhui (No.gxfxZ D2016013)+3 种基金the Natural Science Foundation of the Higher Education Institutions of Anhui Province, China (No. KJ2010B357)Startup Project of Anhui Normal University Doctor ScientificResearch (No.2016XJJ129)the US Nation al Science Foundation under grants CNS1702957 and ACI-1642133the Wireless Engineering Research and Education Center at Auburn University
文摘Multimedia big data brings tremendous challenges as well as opportunities for multimedia applications/services. In this paper, we present a survey and tutorial for multimedia big data. After discussing the characteristics of multimedia big data such as human-centricity, multimodality, heterogeneity, unprecedented volume, and so on, this paper provides an overview of the state-of-the-art of multimedia big data, reviews the latest related technologies, and discusses the technical challenges. We conclude this paper with a discussion of open problems and future directions.
基金This study was funded by the National Natural Science Foundation of China(No.82270396).
文摘Controlling energy expenditure during acute cold exposure is a fundamental aspect of metabolic dynamics in organisms.However,prior studies on cold-induced thermogenesis faced limitations,primarily focusing on brown adipose tissue(BAT)and lacking precise in vivo flux measurements.This editorial aims to highlight the recent research by Bornstein et al.providing a comprehensive and quantitative insight into the intricate alterations in metabolic flux that drive this phenomenon[1].
基金supported by the National Key Research and Development Program of China(2021YFF0701700)the NFSC(21925105 and 92156001)+1 种基金the Natural Science Foundation of Tianjin(grant no.24JCZDJC00700)the Haihe Laboratory of Sustainable Chemical Transformations,and the Fundamental Research Funds for the Central Universities.
文摘Strain-release ring-opening trifluoromethylthiolation to construct SCF3-substituted cyclic motifs was under-explored,and di-trifluoromethylthiolation is unachieved.Herein,we present the first trifluoromethylthiolation of bicyclo[1.1.0]butane(BCB)and bicyclo[2.1.0]pentane.By employing different activators,both mono-and di-trifluoromethylthio substituted cyclobutane and cyclopentane derivatives were successfully obtained.
基金supported by the National Key Research and Development Program of China(2021YFF0701700)the National Natural Science Foundation of China(NFSC)(21925105 and 92156001)+1 种基金the Haihe Laboratory of Sustainable Chemical Transformationsthe Fundamental Research Funds for the Central Universities。
文摘The trifluoromethoxy group(OCF_(3))has garnered significant attention and exhibited unique characteristics in the realms of life sciences,pharmaceuticals,and agrochemicals.The development of efficient methods for synthesizing diverse trifluoromethoxy molecules is therefore of paramount importance.However,due to the weak nucleophilicity and instability of the OCF_(3)group,many catalysts have shown limited applicability in OCF_(3)compound synthesis.Encouragingly,silver catalysts have emerged as notable contenders and have effectively facilitated the synthesis of a variety of alkyl,aromatic and alkenyl OCF_(3)products through direct trifluoromethoxylation and indirect methods.This review aims to provide a comprehensive overview of silvermediated/catalyzed reactions for the synthesis of trifluoromethoxy molecules,focusing particularly on the roles of silver and the reaction mechanisms.
基金supported by the National Key Research and Development Program of China(2016YFA0602900)the National Natural Science Foundation of China(21522205,21672110)the Fundamental Research Funds for the Central Universities
文摘The trifluoromethoxy(CF_3O) group has become a novel moiety in various fields because of its unique features. However, despite the promising applications, the synthesis of CF_3O-containing compounds is still a challenge due to indirect synthetical strategies and volatile reagent which is hard to handle. Until very recently, several innovative reagents were developed to facilitate the trifluoromethoxylation reaction and make CF_3O-containing compounds more accessible. This review mainly focuses on the recent advances in new trifluoromethoxylation reagents and their usage.
基金supported by the National Key Research and Development Program of China(2021YFF0701700)NFSC(21925105,92156001)+2 种基金the Natural Science Foundation of Tianjin(Grant No.18JCJQJC47000)NCC Fund(NCC2020FH07)the Haihe Laboratory of Sustainable Chemical Transformations,and the Fundamental Research Funds for the Central Universities.
文摘Comprehensive Summary,The trifluoromethoxy functional group has received increasing attention in recent years due to its distinctive properties such as good metabolic stability,appropriate lipophilicity and special electrical properties.Thus,the development of new reagents and new strategies of direct trifluoromethoxylation are attracting the enthusiasm of many fluorine chemical workers.At present,nucleophilic and radical trifluoromethoxylating reagents have made major breakthroughs,greatly promoting the development of trifluoromethoxy chemistry.
基金support from the National Natural Science Foundation of China(grant nos.21991121,21931013,21925105,22025103,and 21961142015)the National Key Research and Development Program of China(grant no.2021YFF0701700).
文摘The development of synthetic methods for the introduction of the fluorine atom and fluoroalklyl groups into organic molecules has gained increased attention.Synthetic organic chemists have recently jumped into the field of organofluorine chemistry and have thus made significant contributions.Furthermore,these newly developed methods are typically safer and more effective than the traditional methods.In this review,wewill summarize the representative contributions of new reagents and reactions developed in the past decade.
基金We are deeply indebted to all of the group members.We also thank the National Key Research and Development Program of China(2016YFA0602900)NFSC(21672110,21925105)+1 种基金the Natu-ral Science Foundation of Tianjin(Grant No.18JCIQJC47000)the Fundamental Research Funds for the Central Universities for financial support.
文摘The OCF_(3)group has good metabolic stability,suitable lipophilicity and special electrical properties,which can modify the properties of drugs and material molecules.In recent years,trifluoromethoxy compounds have received more and more attention.Both new reagents and new trifluoromethoxylation strategies got a breakthrough.Our group has been committed to the development of trifluoromethoxylation reagents and methods.This account focuses on describing various trifluoromethoxylation reactions with trifluoromethyl sulfonates(TFMS)and(E)-O-trifluoromethyl-benzaldoximes(TFBO)developed by our group.
基金This work was supported by the National Natural Science Foundation of China(21672105,21725204,91753124)Natural Science Foundation of Tianjin(17JCYBJC19700,18JCZDJC32800)the Fundamental Research Funds for the Central Universities(Nankai University)(63191746).
文摘A radical-mediated method was reported for diastereoselective synthesis of non-classical heteroaryl C-glycosides via Minisci-type alkylation of N-heteroarenes with 4-glycosyl-1,4-dihydropyridine(DHP)reagents.These DHP reagents serve as convenient precursors for various glycosyl radicals under the activation of single electron transfer(SET)oxidation by persulfate and visible light irradiation with or without photocatalyst.
文摘In recent years,the trifluoromethoxy(OCF3)functional group has received extensive attention in phar-maceuticals,agrochemicals and material sciences.However,the methods for the enantioselective syn-thesis of trifluoromethoxylated stereogenic carbon centers are rare owing to the nature of easy decom-position of OCF3 anion and limited OCF3 reagent.And the asymmetric trifluoromethoxylation will be a hot research topic in near future due to the unique biological properties of a single isomer.This article mainly focuses on the recent advances in the enantioselectiveconstruction of trifluoromethoxylated stereogenic carbon centers.
文摘Summary of main observation and conclusion Schisandraceae triterpenoids are novel natural products that contain highly fused ring systems bearing multiple chiral centers surrounding. Some of them exhibit promising bioactivities, such as antitumor, anti‐HIV, etc. In this article, we describe our efforts to the collective total synthesis of schilancidilactones A, B, schilancitrilactones A, B, C, and 20‐epi‐schilancitrilactone A from common precursors. An intramolecular radical cyclization, late‐stage halogenation and AIBN‐mediated or Ni‐catalyzed intermolecular radical cross coupling reaction were employed as the key steps.
文摘Natural products have been identified as one of the most important source for new drug discovery. Among them, we focused on the highly oxygenated natural products due to their important biological activity and diversity structures.
基金supported by the National Key Research and Development Program of China(grant no.2021YFF0701700)the National Natural Science Foundation of China(grant nos.21925105,92156001,and 22101141)+1 种基金the Natural Science Foundation of Tianjin(grant no.18JCJQJC47000)the Haihe Laboratory of Sustainable Chemical Transformations,and the Fundamental Research Funds for the Central Universities.
文摘A rhodium/diene catalyzed asymmetric allylic trifluoromethoxylation reaction is reported,which afforded chiral trifluoromethoxylated allylic compounds in 52%–97%yields with up to 97%enantiomeric excess.These are the first examples of asymmetric allylic trifluoromethoxylation.The reactions proceed via a dynamic kinetic process that allowed for the use of racemic allylic trichloroacetimidates as substrates.Density functional theory calculations showed that the formation of the C–OCF_(3)bond occurs via outer-sphere nucleophilic attack.Importantly,the presence of the allylic group in the products enabled them to be converted into a diverse array of optically active trifluoromethylated molecules that are otherwise difficult to access.
