The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various...The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various applications.Herein,a dual-network(DN)gel was successfully prepared using acrylamide and sodium lignosulphonate as the basic units by simple chemical cross-linking and physical cross-linking methods.Specifically,the hydrogel forms two types of cross-linking networks through metal coordination and hydrogen bonding.Benefiting from the combined effects of dipole polarization and conductivity loss,the gel achieves an effective absorption bandwidth(EAB)of 6.74 GHz at a thickness of only 1.89 mm,demonstrating excellent EMW absorption performance.In addition,this unique structural configuration endows the EMW absorber with multifunctional features,such as remarkable tensile strength,good environmental compatibility,ultraviolet(UV)resistance,and excellent adhesion.Integrating multiple functional features into the EMW gels displays a broad application prospect in a variety of application scenarios.This research reveals the significance of DN structure design in the electromagnetic wave absorption(EWA)performance of gel-based materials,providing a substantial foundation for the multifunctional design of gel-based absorbers.展开更多
Azobenzene-based polymer actuators show great promise for photoactuation owing to their unique photoisomerization behavior and tailorable molecular programmability.However,conventional systems are limited by inadequat...Azobenzene-based polymer actuators show great promise for photoactuation owing to their unique photoisomerization behavior and tailorable molecular programmability.However,conventional systems are limited by inadequate mechanical robustness,self-healing,and recyclability,hindering their practical implementation.Herein,we present a high-performance azobenzene-functionalized polyurethane(AzoPU)elastomer actuator designed via molecular engineering of photoactive azobenzene moieties and dynamic disulfide bonds.AzoPU exhibits exceptional mechanical properties with retained performance after multiple reshaping cycles,enabled by well-engineered hard-soft segments and synergistic stress dissipation from weak covalent bonds/hierarchical hydrogen bonds.It achieves over 93%self-healing efficiency at room temperature owing to the synergistic interplay of disulfide bonds in the polymer backbone and intermolecular hydrogen bonds.Furthermore,it demonstrates remarkable light-triggered actuation behavior,achieving a phototropic bending angle exceeding 180°toward the light source within 45 s.To showcase its practical potential,proof-of-concept photoactuated devices with flower-,hook-,and gripper-like and local-orientation processed strip-shaped structures were fabricated,which exhibited rapid and reversible light-triggered deformation.This study proposes a novel strategy for the development of intelligent polymeric materials that integrate light responsiveness,self-healing,and recyclability,thus holding great promise for applications in flexible electronics,smart actuators,and sustainable functional materials.展开更多
The year 2026 marks the 70th anniversary of the establishment of diplomatic relations between China and African countries.It also marks the launch of the China-Africa Year of People-to-People Exchanges.At this pivotal...The year 2026 marks the 70th anniversary of the establishment of diplomatic relations between China and African countries.It also marks the launch of the China-Africa Year of People-to-People Exchanges.At this pivotal juncture linking past achievements with future development,Wang Yi,member of the Political Bureau of the Communist Party of China Central Committee and foreign minister,continued the longstanding diplomatic tradition under which the Chinese foreign minister makes Africa the destination of the first overseas visit of the year,a practice upheld for 36 consecutive years,underscoring the stability,continuity and sincerity of China’s policy towards Africa.展开更多
The carbonylation of amines offers a promising route for synthesizing N-substituted carbamates with high atom economy.However,conventional catalysts exhibit limited catalytic efficiency,and the underlying proton trans...The carbonylation of amines offers a promising route for synthesizing N-substituted carbamates with high atom economy.However,conventional catalysts exhibit limited catalytic efficiency,and the underlying proton transfer mechanism remains elusive.Herein,we reported a metal-free,room-temperature strategy utilizing 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)as a dual hydrogen bond catalyst to synergistically activate propylamine(PA)and dimethyl carbonate(DMC).This green catalytic system achieves a 10-fold acceleration in reaction rate compared to other hydrogen bonding catalysts under mild conditions.This is enabled by dual hydrogen bonding of TBD with PA and DMC,which facilitates rapid proton transfer and stabilizes tetrahedral intermediates.Theoretical calculations confirm that the dual hydrogen bond system significantly lowers activation energy compared to single hydrogen bond analogs.Furthermore,it was revealed that the hydrogen bonding network within the product is the primary factor responsible for the sluggish reaction rate.This study demonstrates the effectiveness of a dual hydrogen bond system in accelerating the carbonylation of amines and provides a green route to access carbamates.展开更多
Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_...Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_(2)O_(4)=oxalic acid,C_(6)N_(2)H_(11)=2-ethyl-4-methylimidazolium cation and C_(4)N_(2)H_(4)=pyrazine).Remarkably,crystal 2 exhibits an unprecedentedly large birefringence of 0.422 at 550 nm,which surpasses all commercial birefringent crystals.The formation of the directional hydrogen bonds between oxalate and planar pyrazine constituents facilitates the adoption of a planar configuration by oxalic units possessing large polarizability anisotropy(Δα=21.72).Whereas the distorted configuration of oxalate groups with a relatively small Δα of 13.95 induced by the non-coplanar arrangement of the imidazole planes of C_(6)N_(2)H_(11) leads to moderate birefringence(0.144@550 nm)for 1.Computational analyses reveal that the birefringent superiority of 2 originates from the synergistic effect of the π-conjugated oxalate and pyrazine units in a parallel arrangement directed by hydrogen bonds.This work breaks the record of birefringence in oxalates.It also develops a powerful hydrogen bond-directed strategy to modulate the configuration of oxalate groups,enabling its use as a tunable anisotropic structural unit for constructing birefringent crystals.展开更多
Prussian blue analogs(PBAs)have emerged as environmentally friendly and structurally tunable cathode materials for aqueous ammonium-ion batteries(AIBs).However,the fundamental role of crystalline H_(2)O in regulating ...Prussian blue analogs(PBAs)have emerged as environmentally friendly and structurally tunable cathode materials for aqueous ammonium-ion batteries(AIBs).However,the fundamental role of crystalline H_(2)O in regulating ammonium-ion storage and transport remains poorly understood.In this study,we present a comprehensive comparison between hydrated NH_(4)NiHCF-H_(2)O and its anhydrous counterpart NH_(4)NiHCF,revealing the critical contribution of interstitial water to electrochemical performance.Structural and spectroscopic analyses confirm that interstitial water forms robust hydrogen bonds with NH_(4)+ions,stabilizing the PBA framework and mitigating structural degradation during cycling.Electrochemical measurements show that NH_(4)NiHCF-H_(2)O delivers a significantly higher specific capacity of 61 mA h g^(−1)at 0.2 C and markedly improved rate performance compared to NH_(4)NiHCF(48 mA h g^(−1)at 0.2 C).Kinetic analysis reveals that interstitial water enhances NH_(4)+diffusion,as evidenced by higher diffusion coefficients.Furthermore,density functional theory(DFT)calculations demonstrate that crystal water acts as a hydrogen bond acceptor,preferentially interacting with NH_(4)+and reducing the migration energy barrier,thereby facilitating fast ion transport.This work provides fundamental insights into the role of crystal water in PBAs and offers a rational design strategy for improving the kinetics,structural stability of PBAs cathodes for AIBs.展开更多
Superconductivity in two-dimensional(2D)materials has attracted considerable attention due to their unique physical properties and potential for high-temperature operation.Boron-based 2D compounds are particularly pro...Superconductivity in two-dimensional(2D)materials has attracted considerable attention due to their unique physical properties and potential for high-temperature operation.Boron-based 2D compounds are particularly promising,thanks to their structural flexibility and the emergence of strong electron-phonon coupling(EPC)associated with light elements.While most previous studies have focused on stabilizing boron sheets through metal incorporation,we propose an alternative approach based on multicenter bonding enabled by group-IV non-metallic elements(Si,Ge,Sn).The resulting XB_(2)(X=Si,Ge,Sn)monolayers,which adopt a MgB_(2)-like monolayer configuration,are stabilized by a seven-center two-electron(7c-2e)bonding network between the X atoms and the boron honeycomb lattice.This bonding lowers the energy of the B-p_(z)orbitals and enhances lattice stability.The superconducting transition temperature(T_(c))increases significantly with the atomic number of X—from 4.7 K in SiB_(2)to 13.3 K in GeB_(2)and 24.9 K in SnB_(2)—driven by an increased carrier density near the Fermi level(E_(F))and softening of the high-frequency E_(2)phonon mode.Furthermore,we design a SnB_4 monolayer,in which a Sn layer is sandwiched between the two boron layers.This structure enriches in-plane phonon modes and strengthens EPC,yielding a T_(c)of 38 K,close to the McMillan limit.These findings highlight the critical role of multicenter bonding and targeted phonon engineering in enabling high-T_(c)2D boron-based superconductors.展开更多
Quantifying the hydrogen bond(H-bond)strength of polymers is essential for rational design of advanced materials.However,direct measurement remains challenging because of the structural complexity of polymers and the ...Quantifying the hydrogen bond(H-bond)strength of polymers is essential for rational design of advanced materials.However,direct measurement remains challenging because of the structural complexity of polymers and the weak nature of H-bonds.Vacuum-based singlemolecule force spectroscopy(Vac-SMFS)offers a new and precise approach for such measurements.Using polyallylamine(PAAm)as a model polymer,the intrinsic strength(i.e.,strength without external influences)of representative N―H…N H-bonds was quantified to be about 5.25 kJ·mol^(–1).Comparative Vac-SMFS analysis across different polymer systems revealed that the N―H…N H-bonds in PAAm are unexpectedly stronger than the N―H…O H-bonds in poly(N-isopropylacrylamide)(PNIPAM)and the O―H…O H-bonds in poly(hydroxyethyl methacrylate)(PHEMA).This trend contrasts with that of established small-molecule systems.These results highlight how side-chain length and spatial configuration dictate polymer H-bond strengths,expanding the fundamental knowledge of polymer interactions and enabling the rational design of next-generation functional materials.展开更多
Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains...Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains a confusing topic.Here we develop a hydrogen-bond-oriented interfacial super-assembly strategy to custom-tailor nanosheet-intertwined spherical carbon superstructures(SCSs)for Zn-ion storage with double-high capacitive activity and durability.Tetrachlorobenzoquinone(H-bond acceptor)and dimethylbenzidine(H-bond donator)can interact to form organic nanosheet modules,which are sequentially assembled,orientally compacted and densified into well-orchestrated superstructures through multiple H-bonds(N-H···O).Featured with rich surface-active heterodiatomic motifs,more exposed nanoporous channels,and successive charge migration paths,SCSs cathode promises high accessibility of built-in zincophilic sites and rapid ion diffusion with low energy barriers(3.3Ωs-0.5).Consequently,the assembled Zn||SCSs capacitor harvests all-round improvement in Zn-ion storage metrics,including high energy density(166 Wh kg-1),high-rate performance(172 m Ah g^(-1)at 20 A g^(-1)),and long-lasting cycling lifespan(95.5%capacity retention after 500,000 cycles).An opposite chargecarrier storage mechanism is rationalized for SCSs cathode to maximize spatial capacitive charge storage,involving high-kinetics physical Zn^(2+)/CF_(3)SO_(3)-adsorption and chemical Zn^(2+)redox with carbonyl/pyridine groups.This work gives insights into H-bond-guided interfacial superassembly design of superstructural carbons toward advanced energy storage.展开更多
High-pressure electrides,characterized by the presence of interstitial quasi-atoms(ISQs),possess unique electronic structures and physical properties,such as diverse dimensions of electride states exhibiting different...High-pressure electrides,characterized by the presence of interstitial quasi-atoms(ISQs),possess unique electronic structures and physical properties,such as diverse dimensions of electride states exhibiting different superconductivity,which has attracted significant attention.Here,we report a new electron-deficient type of electride Li_(4)Al and identify its phase transition progress with pressurization,where the internal driving force behind phase transitions,bonding characteristics,and superconducting behaviors have been revealed based on first-principles density functional theory.Through analysis of the bonding properties of electride Li_(4)Al,we demonstrate that the ISQs exhibiting increasingly covalent characteristics between Al ions play a critical role in driving the phase transition.Our electron–phonon coupling calculations indicate that all phases exhibit superconducting behaviors.Importantly,we prove that the ISQs behave as free electrons and demonstrate that the factor governing T_(c) is primarily derived from Li-p-hybridized electronic states with ISQ compositions.These electronic states are scattered by low-frequency phonons arising from mixed vibrations of Li and Al affected by ISQs to enhance electron–phonon coupling.Our study largely expands the research scope of electrides,provides new insight for understanding phase transitions,and elucidates the effects of ISQs on superconducting behavior.展开更多
Recurrence of solid tumors after surgical resection is a major barrier to tissue regeneration.As an emerging treatment strategy,photo-thermo-electric therapy ablates tumor cells via photothermal effects and generates ...Recurrence of solid tumors after surgical resection is a major barrier to tissue regeneration.As an emerging treatment strategy,photo-thermo-electric therapy ablates tumor cells via photothermal effects and generates reactive oxygen species(ROS)via thermoelectric effects to disrupt heat shock proteins,thereby suppressing their protective function in tumor cells.However,conventional materials suffer from low thermoelectric efficiency and weak tissue penetration ability.In this study,we fabricated iodine-doped bismuth sulfide(I-Bi_(2)S_(3))nanorods with bonding heterostructures to improve thermoelectric performance.The approach employed iodine doping to introduce additional electrons,thereby regulating the band structure of Bi_(2)S_(3)and exploiting the dual low-energy vibration effect of the heterostructures to reduce thermal conductivity.More importantly,controlling the type of heterostructure modulated the bandgap width,thereby expanding the light absorption range to the higher-penetration near-infrared(NIR)-Ⅱregion for deep tissue treatment.The I-Bi_(2)S_(3)nanorods were incorporated into poly-L-lactic acid(PLLA)scaffolds to confer antitumor functionality.According to the results,the bonding heterostructures enhanced the conductivity of Bi_(2)S_(3)and reduced its thermal conductivity,significantly enhancing thermoelectric efficacy.The heterostructures reduced the bandgap of Bi_(2)S_(3)from 1.23 to 0.88 eV,enabling optical absorption in the NIR-Ⅱregion.The ROS tests showed that the PLLA/I-Bi_(2)S_(3)scaffold exhibited good photothermal effects and ROS generation under 1064-nm laser irradiation.The antitumor efficacy of the PLLA/I-Bi_(2)S_(3)scaffold reached 84.6%against MG-63 cells,demonstrating its exceptional potential in cancer treatment.展开更多
Controllable photoreaction transition of photosensitizers(PSs)provides a highly promising approach for achieving efficient photodynamic therapy(PDT).However,tumor microenvironment-triggered phototransition remains a s...Controllable photoreaction transition of photosensitizers(PSs)provides a highly promising approach for achieving efficient photodynamic therapy(PDT).However,tumor microenvironment-triggered phototransition remains a significant challenge and has not yet been reported.In this work,we develop a hydrogen bond self-assembly(HBSA)strategy that is triggered by the acidic tumor microenvironment to enable the photodynamic transition of tetra(4-carboxylphenyl)porphyrin(TCPP)PSs from type Ⅱ to type Ⅰ reactions.Upon self-assembly of TCPP monomers into TCPP assemblies(TCPP-ass),the generated reactive oxygen species shift from singlet oxygen to superoxide anions,which induces caspase-3/GSDME-mediated programmed pyroptosis,enabling rapid and complete solid tumor elimination with minimized adverse effects and enhanced therapeutic efficacy.Crucially,the HBSA process occurs exclusively within tumor cells,and this tumor-specific self-assembly strategy not only utilizes high tissue penetration of TCPP molecular-PSs,but also avoids phototoxicity caused by the formation and accumulation of TCPP-ass nano-PSs in normal tissue,providing an innovative approach for precise cancer therapy.展开更多
When stacking two-dimensional(2D)materials with a lattice mismatch and/or a small twist,moirésuperlattice emerges with fascinating electronic and optical properties.The fabrication of such stacked 2D materials us...When stacking two-dimensional(2D)materials with a lattice mismatch and/or a small twist,moirésuperlattice emerges with fascinating electronic and optical properties.The fabrication of such stacked 2D materials usually requires multiple transfer and stack processes,assisted by a certain transfer medium which needs to be removed afterwards,and it is very challenging to maintain pristine and clean surfaces/interfaces for these stacked structures.In this work,we report a facile direct bonding method for fabrication of twisted MoS_(2) bilayers with ultra-clean surfaces/interfaces.Novel interlayer interactions are revealed in the as-fabricated high-quality samples,leading to twist-angle related dispersion behavior of various Raman modes,such as layer breathing modes,shear modes and E_(2g)modes,as well as indirect bandgap excitons.Field-effect transistors(FETs)of twisted MoS_(2) bilayers also exhibit angle-dependent performance,which could be attributed to the band structure evolution.This facile method holds significance for the future integration of pre-designed multilayer 2D materials and paves a way to explore underlying physical mechanisms and potential applications.展开更多
Solid-state lithium(Li)batteries are hailed as the nextgeneration energy storage technology,garnering significant attention for their potential high energy density and safety.Particularly when using Li-rich manganese ...Solid-state lithium(Li)batteries are hailed as the nextgeneration energy storage technology,garnering significant attention for their potential high energy density and safety.Particularly when using Li-rich manganese layered oxide(LRMO)as cathodes(theoretical capacity exceeding250 mAh/g),energy densities over 600 Wh/kg can be theoretically achieved[1,2].展开更多
The current technical standards primarily relied on experience to judge the interfacial bonding properties between the self-compacting concrete filling layer and the steam-cured concrete precast slab in CRTS Ⅲ slab b...The current technical standards primarily relied on experience to judge the interfacial bonding properties between the self-compacting concrete filling layer and the steam-cured concrete precast slab in CRTS Ⅲ slab ballastless track structure.This study sought to enhance technical standards for evaluating interfacial bonding properties by suggesting the use of the splitting tensile strength to evaluate the impact of bubble defects.Specimens were fabricated through on-site experiment.The percent of each area of 6 cm^(2)or more bubble defect was 0 in most of specimens.When the cumulative area of all bub-ble defects reached 12%,the splitting tensile strength value was 0.67 MPa,which exceeded the minimum required value of 0.5 MPa for ensuring bonding interface adhesion.Furthermore,when the cumulative area of all bubble defects reached 8%,the splitting tensile strength value was 0.85 MPa,which exceeded the minimum required value of 0.8 MPa,thereby over-coming the negative impact of each area of 10 cm^(2) or more bubble defect.Additionally,keeping the cumulative area of each area of 6 cm^(2) or more bubble defect below 6%ensured adequate bonding strength and reduced the occurrence of specimens with lower splitting tensile strength values.展开更多
Effective treatment of subcutaneous tumors remains a focal point in cancer therapy.Photothermal therapy,a novel therapeutic approach,has emerged as a promising alternative,offering a less invasive option for the treat...Effective treatment of subcutaneous tumors remains a focal point in cancer therapy.Photothermal therapy,a novel therapeutic approach,has emerged as a promising alternative,offering a less invasive option for the treatment of subcutaneous tumors.This study reports the exploration of novel supramolecular halogen-bonded organic frameworks(XOFs)based on[N…Br^(+)…N]halogen bonds through the ligand exchange strategy and their application in photothermal therapy.Through ligand exchange,XOF(Br)-TPy was successfully prepared,and its structure and properties were thoroughly characterized using NMR,XPS,FT-IR,and XRD techniques.Due to their cationic characteristics,these XOFs serve as effective carriers for the photothermal agent IR820.In vitro experiments demonstrated that the IR820@XOF(Br)-TPy composite exhibits excellent photothermal conversion efficiency under NIR irradiation,effectively inducing tumor cell ablation.Furthermore,in vivo studies confirmed the remarkable antitumor efficacy of the composite material in a subcutaneous tumor model.This work demonstrates that the ligand exchange strategy is a versatile and facile approach for constructing XOFs(Br)and provides a novel strategy for developing advanced photothermal therapeutic agents with significant application potential.展开更多
Catalytic reduction reactions using isopropanol(IPA)as a transfer hydrogenating agent are gaining significant attention due to the low cost and large-scale production of IPA.Traditional methods for carbon-carbon(C—C)...Catalytic reduction reactions using isopropanol(IPA)as a transfer hydrogenating agent are gaining significant attention due to the low cost and large-scale production of IPA.Traditional methods for carbon-carbon(C—C)bond construction often rely on expensive and scarce transition metal catalysts,raising concerns about sustainability and environmental impact.To address these challenges,we develop a bifunctional photocatalyst,phloroglucinol carbon quantum dot(PG-CQD).It facilitates catalytic transfer hydrogenation(CTH)with IPA as the hydrogen donor.PG-CQDs exhibit both dehydrogenation and reduction activities,enabling the formation of vicinal diols under mild conditions with visible light irradiation.We propose a CTH mechanism that has been successfully validated through experiments.The catalytic system demonstrates remarkable versatility,enabling the synthesis of various vicinal diols from diverseα-keto ester substrates with good or excellent yields.These findings offer a sustainable synthetic strategy that aligns with green chemistry principles and establish a promising pathway for the development of environmentally benign and energy-efficient organic transformations.展开更多
Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding str...Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding strength in titanium/stainless steel laminated composites were investigated.Results indicate that the hardened layer reduces the interfacial bonding strength from over 261 MPa to less than 204 MPa.During the cold roll-bonding process,the hardened layer fractures,leading to the formation of multi-scale cracks that are difficult for the stainless steel to fill.This not only hinders the development of an interlocking interface but also leads to the presence of numerous microcracks and hardened blocks along the nearly straight interface,consequently weakening the interfacial bonding strength.In metals with high work hardening rates,the conventional approach of enhancing interface interlocking and improving interfacial bonding strength by using a surface-hardened layer becomes less effective.展开更多
The regioselective carbon-hydrogen bond functionalization reaction in atom-and step-economy holds significant potential for the late-stage elaboration of complex molecules and natural products.In recent years,the hydr...The regioselective carbon-hydrogen bond functionalization reaction in atom-and step-economy holds significant potential for the late-stage elaboration of complex molecules and natural products.In recent years,the hydrogen atom transfer strategy involving radicals has garnered considerable attention from chemists due to its high chemoselectivity and regioselectivity.However,owing to the marginal differences in bond dissociation energies(BDEs)among C(sp^(3))—H bonds,hydrogen atom transfer reactions mediated by alkyl radicals remain less-developed.A copper-catalyzed sulfone-induced regioselective C(sp^(3))—H bond heteroarylation reaction was reported.This strategy utilizes theα-alkyl radical of sulfone as an intramolecular hydrogen abstraction reagent,enabling the regioselective formation of carbon-nitrogen bonds under copper catalysis.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52231007,51872238,52074227,and 21806129)the Fundamental Research Funds for the Central Universities(Nos.3102018zy045,3102019AX11,and 5000220455)the Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2017JQ5116 and 2020JM-118).
文摘The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various applications.Herein,a dual-network(DN)gel was successfully prepared using acrylamide and sodium lignosulphonate as the basic units by simple chemical cross-linking and physical cross-linking methods.Specifically,the hydrogel forms two types of cross-linking networks through metal coordination and hydrogen bonding.Benefiting from the combined effects of dipole polarization and conductivity loss,the gel achieves an effective absorption bandwidth(EAB)of 6.74 GHz at a thickness of only 1.89 mm,demonstrating excellent EMW absorption performance.In addition,this unique structural configuration endows the EMW absorber with multifunctional features,such as remarkable tensile strength,good environmental compatibility,ultraviolet(UV)resistance,and excellent adhesion.Integrating multiple functional features into the EMW gels displays a broad application prospect in a variety of application scenarios.This research reveals the significance of DN structure design in the electromagnetic wave absorption(EWA)performance of gel-based materials,providing a substantial foundation for the multifunctional design of gel-based absorbers.
基金financially supported by the National Natural Science Foundation of China(No.52503154)Shandong Provincial Natural Science Foundation(Nos.ZR2022MB034 and ZR2025QC512)。
文摘Azobenzene-based polymer actuators show great promise for photoactuation owing to their unique photoisomerization behavior and tailorable molecular programmability.However,conventional systems are limited by inadequate mechanical robustness,self-healing,and recyclability,hindering their practical implementation.Herein,we present a high-performance azobenzene-functionalized polyurethane(AzoPU)elastomer actuator designed via molecular engineering of photoactive azobenzene moieties and dynamic disulfide bonds.AzoPU exhibits exceptional mechanical properties with retained performance after multiple reshaping cycles,enabled by well-engineered hard-soft segments and synergistic stress dissipation from weak covalent bonds/hierarchical hydrogen bonds.It achieves over 93%self-healing efficiency at room temperature owing to the synergistic interplay of disulfide bonds in the polymer backbone and intermolecular hydrogen bonds.Furthermore,it demonstrates remarkable light-triggered actuation behavior,achieving a phototropic bending angle exceeding 180°toward the light source within 45 s.To showcase its practical potential,proof-of-concept photoactuated devices with flower-,hook-,and gripper-like and local-orientation processed strip-shaped structures were fabricated,which exhibited rapid and reversible light-triggered deformation.This study proposes a novel strategy for the development of intelligent polymeric materials that integrate light responsiveness,self-healing,and recyclability,thus holding great promise for applications in flexible electronics,smart actuators,and sustainable functional materials.
文摘The year 2026 marks the 70th anniversary of the establishment of diplomatic relations between China and African countries.It also marks the launch of the China-Africa Year of People-to-People Exchanges.At this pivotal juncture linking past achievements with future development,Wang Yi,member of the Political Bureau of the Communist Party of China Central Committee and foreign minister,continued the longstanding diplomatic tradition under which the Chinese foreign minister makes Africa the destination of the first overseas visit of the year,a practice upheld for 36 consecutive years,underscoring the stability,continuity and sincerity of China’s policy towards Africa.
基金financially supported by the National Key R&D Program of China(2023YFC3905400)the Clean Combustion and Low-carbon Utilization of Coal,Strategic Priority Research Program of the Chinese Academy of Sciences,Grant No.XDA 29000000.
文摘The carbonylation of amines offers a promising route for synthesizing N-substituted carbamates with high atom economy.However,conventional catalysts exhibit limited catalytic efficiency,and the underlying proton transfer mechanism remains elusive.Herein,we reported a metal-free,room-temperature strategy utilizing 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)as a dual hydrogen bond catalyst to synergistically activate propylamine(PA)and dimethyl carbonate(DMC).This green catalytic system achieves a 10-fold acceleration in reaction rate compared to other hydrogen bonding catalysts under mild conditions.This is enabled by dual hydrogen bonding of TBD with PA and DMC,which facilitates rapid proton transfer and stabilizes tetrahedral intermediates.Theoretical calculations confirm that the dual hydrogen bond system significantly lowers activation energy compared to single hydrogen bond analogs.Furthermore,it was revealed that the hydrogen bonding network within the product is the primary factor responsible for the sluggish reaction rate.This study demonstrates the effectiveness of a dual hydrogen bond system in accelerating the carbonylation of amines and provides a green route to access carbamates.
基金supported by the National Natural Science Foundation of China(22361021,22261023)。
文摘Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_(2)O_(4)=oxalic acid,C_(6)N_(2)H_(11)=2-ethyl-4-methylimidazolium cation and C_(4)N_(2)H_(4)=pyrazine).Remarkably,crystal 2 exhibits an unprecedentedly large birefringence of 0.422 at 550 nm,which surpasses all commercial birefringent crystals.The formation of the directional hydrogen bonds between oxalate and planar pyrazine constituents facilitates the adoption of a planar configuration by oxalic units possessing large polarizability anisotropy(Δα=21.72).Whereas the distorted configuration of oxalate groups with a relatively small Δα of 13.95 induced by the non-coplanar arrangement of the imidazole planes of C_(6)N_(2)H_(11) leads to moderate birefringence(0.144@550 nm)for 1.Computational analyses reveal that the birefringent superiority of 2 originates from the synergistic effect of the π-conjugated oxalate and pyrazine units in a parallel arrangement directed by hydrogen bonds.This work breaks the record of birefringence in oxalates.It also develops a powerful hydrogen bond-directed strategy to modulate the configuration of oxalate groups,enabling its use as a tunable anisotropic structural unit for constructing birefringent crystals.
基金supported by the National Natural Science Foundation of China (52172227)the Natural Science Foundation of Hubei Province (2023AFA114)+2 种基金the Guizhou Provincial Key Technology R&D Program (ZD[2025]019)provided by the Startup Fund (20QD80 and 22QD28)support from the Science&Technology Top Talents Program of Guizhou Province ([2024]349)
文摘Prussian blue analogs(PBAs)have emerged as environmentally friendly and structurally tunable cathode materials for aqueous ammonium-ion batteries(AIBs).However,the fundamental role of crystalline H_(2)O in regulating ammonium-ion storage and transport remains poorly understood.In this study,we present a comprehensive comparison between hydrated NH_(4)NiHCF-H_(2)O and its anhydrous counterpart NH_(4)NiHCF,revealing the critical contribution of interstitial water to electrochemical performance.Structural and spectroscopic analyses confirm that interstitial water forms robust hydrogen bonds with NH_(4)+ions,stabilizing the PBA framework and mitigating structural degradation during cycling.Electrochemical measurements show that NH_(4)NiHCF-H_(2)O delivers a significantly higher specific capacity of 61 mA h g^(−1)at 0.2 C and markedly improved rate performance compared to NH_(4)NiHCF(48 mA h g^(−1)at 0.2 C).Kinetic analysis reveals that interstitial water enhances NH_(4)+diffusion,as evidenced by higher diffusion coefficients.Furthermore,density functional theory(DFT)calculations demonstrate that crystal water acts as a hydrogen bond acceptor,preferentially interacting with NH_(4)+and reducing the migration energy barrier,thereby facilitating fast ion transport.This work provides fundamental insights into the role of crystal water in PBAs and offers a rational design strategy for improving the kinetics,structural stability of PBAs cathodes for AIBs.
基金supported by the National Natural Science Foundation of China(Grant Nos.22372142,12304028,12404027)the Foreign Expert Introduction Program(Grant No.G2023003004L)+6 种基金the Central Guiding Local Science and Technology Development Fund Projects(Grant No.236Z7605G)the Natural Science Foundation of Hebei Province(Grant Nos.B2024203051,A2024203023,A2024203002)the Science and Technology Project of Hebei Education Department(Grant No.JZX2023020)the Innovation Capability Improvement Project of Hebei Province(Grant No.22567605H)the Hebei Province Yan Zhao Huang Jin Tai Talent Program(Postdoctoral Platform,Grant No.B2024003003)the financial support from the Spanish Ministry of Science and Innovation(Grant No.PID2022139230NB-I00)the Department of Education,Universities and Research of the Basque Government and the University of the Basque Country(Grant No.IT1707-22)。
文摘Superconductivity in two-dimensional(2D)materials has attracted considerable attention due to their unique physical properties and potential for high-temperature operation.Boron-based 2D compounds are particularly promising,thanks to their structural flexibility and the emergence of strong electron-phonon coupling(EPC)associated with light elements.While most previous studies have focused on stabilizing boron sheets through metal incorporation,we propose an alternative approach based on multicenter bonding enabled by group-IV non-metallic elements(Si,Ge,Sn).The resulting XB_(2)(X=Si,Ge,Sn)monolayers,which adopt a MgB_(2)-like monolayer configuration,are stabilized by a seven-center two-electron(7c-2e)bonding network between the X atoms and the boron honeycomb lattice.This bonding lowers the energy of the B-p_(z)orbitals and enhances lattice stability.The superconducting transition temperature(T_(c))increases significantly with the atomic number of X—from 4.7 K in SiB_(2)to 13.3 K in GeB_(2)and 24.9 K in SnB_(2)—driven by an increased carrier density near the Fermi level(E_(F))and softening of the high-frequency E_(2)phonon mode.Furthermore,we design a SnB_4 monolayer,in which a Sn layer is sandwiched between the two boron layers.This structure enriches in-plane phonon modes and strengthens EPC,yielding a T_(c)of 38 K,close to the McMillan limit.These findings highlight the critical role of multicenter bonding and targeted phonon engineering in enabling high-T_(c)2D boron-based superconductors.
基金financially supported by the National Natural Science Foundation of China(No.22273079)Fundamental Research Funds for the Central Universities(No.2682025ZTPY004)。
文摘Quantifying the hydrogen bond(H-bond)strength of polymers is essential for rational design of advanced materials.However,direct measurement remains challenging because of the structural complexity of polymers and the weak nature of H-bonds.Vacuum-based singlemolecule force spectroscopy(Vac-SMFS)offers a new and precise approach for such measurements.Using polyallylamine(PAAm)as a model polymer,the intrinsic strength(i.e.,strength without external influences)of representative N―H…N H-bonds was quantified to be about 5.25 kJ·mol^(–1).Comparative Vac-SMFS analysis across different polymer systems revealed that the N―H…N H-bonds in PAAm are unexpectedly stronger than the N―H…O H-bonds in poly(N-isopropylacrylamide)(PNIPAM)and the O―H…O H-bonds in poly(hydroxyethyl methacrylate)(PHEMA).This trend contrasts with that of established small-molecule systems.These results highlight how side-chain length and spatial configuration dictate polymer H-bond strengths,expanding the fundamental knowledge of polymer interactions and enabling the rational design of next-generation functional materials.
基金financially supported by the National Natural Science Foundation of China(Nos.22272118,22172111,and 22309134)the Science and Technology Commission of Shanghai Municipality,China(Nos.22ZR1464100,20ZR1460300,and 19DZ2271500)+2 种基金the China Postdoctoral Science Foundation(2022M712402),the Shanghai Rising-Star Program(23YF1449200)the Zhejiang Provincial Science and Technology Project(2022C01182)the Fundamental Research Funds for the Central Universities(2023-3-YB-07)。
文摘Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains a confusing topic.Here we develop a hydrogen-bond-oriented interfacial super-assembly strategy to custom-tailor nanosheet-intertwined spherical carbon superstructures(SCSs)for Zn-ion storage with double-high capacitive activity and durability.Tetrachlorobenzoquinone(H-bond acceptor)and dimethylbenzidine(H-bond donator)can interact to form organic nanosheet modules,which are sequentially assembled,orientally compacted and densified into well-orchestrated superstructures through multiple H-bonds(N-H···O).Featured with rich surface-active heterodiatomic motifs,more exposed nanoporous channels,and successive charge migration paths,SCSs cathode promises high accessibility of built-in zincophilic sites and rapid ion diffusion with low energy barriers(3.3Ωs-0.5).Consequently,the assembled Zn||SCSs capacitor harvests all-round improvement in Zn-ion storage metrics,including high energy density(166 Wh kg-1),high-rate performance(172 m Ah g^(-1)at 20 A g^(-1)),and long-lasting cycling lifespan(95.5%capacity retention after 500,000 cycles).An opposite chargecarrier storage mechanism is rationalized for SCSs cathode to maximize spatial capacitive charge storage,involving high-kinetics physical Zn^(2+)/CF_(3)SO_(3)-adsorption and chemical Zn^(2+)redox with carbonyl/pyridine groups.This work gives insights into H-bond-guided interfacial superassembly design of superstructural carbons toward advanced energy storage.
基金supported by the National Key Research and Development Program of China (Grant Nos.2023YFA1406200 and 2022YFA-1405500)the National Natural Science Foundation of China (Grant Nos.12304021 and 52072188)+3 种基金Zhejiang Provincial Natural Science Foundation of China (Grant Nos.LQ23A040004 and MS26A040028)Natural Science Foundation of Ningbo (Grant Nos.2022J091 and ZX2025001430)the Program for Science and Technology Innovation Team in Zhejiang (Grant No.2021R01004)the Program for Changjiang Scholars and Innovative Research Team in University (Grant No.IRT_15R23)。
文摘High-pressure electrides,characterized by the presence of interstitial quasi-atoms(ISQs),possess unique electronic structures and physical properties,such as diverse dimensions of electride states exhibiting different superconductivity,which has attracted significant attention.Here,we report a new electron-deficient type of electride Li_(4)Al and identify its phase transition progress with pressurization,where the internal driving force behind phase transitions,bonding characteristics,and superconducting behaviors have been revealed based on first-principles density functional theory.Through analysis of the bonding properties of electride Li_(4)Al,we demonstrate that the ISQs exhibiting increasingly covalent characteristics between Al ions play a critical role in driving the phase transition.Our electron–phonon coupling calculations indicate that all phases exhibit superconducting behaviors.Importantly,we prove that the ISQs behave as free electrons and demonstrate that the factor governing T_(c) is primarily derived from Li-p-hybridized electronic states with ISQ compositions.These electronic states are scattered by low-frequency phonons arising from mixed vibrations of Li and Al affected by ISQs to enhance electron–phonon coupling.Our study largely expands the research scope of electrides,provides new insight for understanding phase transitions,and elucidates the effects of ISQs on superconducting behavior.
基金National Key Research and Development Program of China(No.2023YFB4605800)The National Natural Science Foundation of China(Nos.52475362,52365046,and 52465041)+3 种基金Jiangxi Provincial Natural Science Foundation of China(No.20224ACB204013)Jiangxi Provincial Key Laboratory of Additive Manufacturing of Implantable Medical Device(No.2024SSY11161)Jiangxi Provincial Department of Education Science and Technology Project(No.GJJ2400708)Jiangxi Province Science and Technology Program(Nos.20252BAC200317 and 20252BEJ730195)。
文摘Recurrence of solid tumors after surgical resection is a major barrier to tissue regeneration.As an emerging treatment strategy,photo-thermo-electric therapy ablates tumor cells via photothermal effects and generates reactive oxygen species(ROS)via thermoelectric effects to disrupt heat shock proteins,thereby suppressing their protective function in tumor cells.However,conventional materials suffer from low thermoelectric efficiency and weak tissue penetration ability.In this study,we fabricated iodine-doped bismuth sulfide(I-Bi_(2)S_(3))nanorods with bonding heterostructures to improve thermoelectric performance.The approach employed iodine doping to introduce additional electrons,thereby regulating the band structure of Bi_(2)S_(3)and exploiting the dual low-energy vibration effect of the heterostructures to reduce thermal conductivity.More importantly,controlling the type of heterostructure modulated the bandgap width,thereby expanding the light absorption range to the higher-penetration near-infrared(NIR)-Ⅱregion for deep tissue treatment.The I-Bi_(2)S_(3)nanorods were incorporated into poly-L-lactic acid(PLLA)scaffolds to confer antitumor functionality.According to the results,the bonding heterostructures enhanced the conductivity of Bi_(2)S_(3)and reduced its thermal conductivity,significantly enhancing thermoelectric efficacy.The heterostructures reduced the bandgap of Bi_(2)S_(3)from 1.23 to 0.88 eV,enabling optical absorption in the NIR-Ⅱregion.The ROS tests showed that the PLLA/I-Bi_(2)S_(3)scaffold exhibited good photothermal effects and ROS generation under 1064-nm laser irradiation.The antitumor efficacy of the PLLA/I-Bi_(2)S_(3)scaffold reached 84.6%against MG-63 cells,demonstrating its exceptional potential in cancer treatment.
基金supported by the National Natural Science Foundation of China(22176058)the Science and Technology Commission of Shanghai Municipality(24DX1400200,23ZR1416100,25ZR1401082)+1 种基金the Program of Introducing Talents of Discipline to Universities(B16017)the Fundamental Research Funds for the Central Universities(222201717003)。
文摘Controllable photoreaction transition of photosensitizers(PSs)provides a highly promising approach for achieving efficient photodynamic therapy(PDT).However,tumor microenvironment-triggered phototransition remains a significant challenge and has not yet been reported.In this work,we develop a hydrogen bond self-assembly(HBSA)strategy that is triggered by the acidic tumor microenvironment to enable the photodynamic transition of tetra(4-carboxylphenyl)porphyrin(TCPP)PSs from type Ⅱ to type Ⅰ reactions.Upon self-assembly of TCPP monomers into TCPP assemblies(TCPP-ass),the generated reactive oxygen species shift from singlet oxygen to superoxide anions,which induces caspase-3/GSDME-mediated programmed pyroptosis,enabling rapid and complete solid tumor elimination with minimized adverse effects and enhanced therapeutic efficacy.Crucially,the HBSA process occurs exclusively within tumor cells,and this tumor-specific self-assembly strategy not only utilizes high tissue penetration of TCPP molecular-PSs,but also avoids phototoxicity caused by the formation and accumulation of TCPP-ass nano-PSs in normal tissue,providing an innovative approach for precise cancer therapy.
基金supported by Guangdong Major Project of Basic and Applied Basic Research(Grant No.2021B0301030002)the National Key Research and Development Program(Grant No.2021YFA1202900)the National Natural Science Foundation of China(Grant Nos.62204166 and 62404145)。
文摘When stacking two-dimensional(2D)materials with a lattice mismatch and/or a small twist,moirésuperlattice emerges with fascinating electronic and optical properties.The fabrication of such stacked 2D materials usually requires multiple transfer and stack processes,assisted by a certain transfer medium which needs to be removed afterwards,and it is very challenging to maintain pristine and clean surfaces/interfaces for these stacked structures.In this work,we report a facile direct bonding method for fabrication of twisted MoS_(2) bilayers with ultra-clean surfaces/interfaces.Novel interlayer interactions are revealed in the as-fabricated high-quality samples,leading to twist-angle related dispersion behavior of various Raman modes,such as layer breathing modes,shear modes and E_(2g)modes,as well as indirect bandgap excitons.Field-effect transistors(FETs)of twisted MoS_(2) bilayers also exhibit angle-dependent performance,which could be attributed to the band structure evolution.This facile method holds significance for the future integration of pre-designed multilayer 2D materials and paves a way to explore underlying physical mechanisms and potential applications.
基金supported by the National Natural Science Foundation of China(No.22479021).
文摘Solid-state lithium(Li)batteries are hailed as the nextgeneration energy storage technology,garnering significant attention for their potential high energy density and safety.Particularly when using Li-rich manganese layered oxide(LRMO)as cathodes(theoretical capacity exceeding250 mAh/g),energy densities over 600 Wh/kg can be theoretically achieved[1,2].
基金supported by a grant from China railway corporation science and technology research and development plan project(Grant No.2017G005-B)funding support by Wuyi University’s Hong Kong and Macao Joint Research and Development Fund(Grants No.2021WGALH15)funding support by the Innovation and Technology Commission of Hong Kong SAR Government to the Hong Kong Branch of National Rail Transit Electrification and Automation Engineering Technology Research Center(Grant No.K-BBY1).
文摘The current technical standards primarily relied on experience to judge the interfacial bonding properties between the self-compacting concrete filling layer and the steam-cured concrete precast slab in CRTS Ⅲ slab ballastless track structure.This study sought to enhance technical standards for evaluating interfacial bonding properties by suggesting the use of the splitting tensile strength to evaluate the impact of bubble defects.Specimens were fabricated through on-site experiment.The percent of each area of 6 cm^(2)or more bubble defect was 0 in most of specimens.When the cumulative area of all bub-ble defects reached 12%,the splitting tensile strength value was 0.67 MPa,which exceeded the minimum required value of 0.5 MPa for ensuring bonding interface adhesion.Furthermore,when the cumulative area of all bubble defects reached 8%,the splitting tensile strength value was 0.85 MPa,which exceeded the minimum required value of 0.8 MPa,thereby over-coming the negative impact of each area of 10 cm^(2) or more bubble defect.Additionally,keeping the cumulative area of each area of 6 cm^(2) or more bubble defect below 6%ensured adequate bonding strength and reduced the occurrence of specimens with lower splitting tensile strength values.
基金supported by the National Natural Science Foundation of China(Nos.22371218,82271518,21801194)Xianyang Bureau of Science and Technology(No.L2024-QCY-ZYYJJQ-260)+2 种基金The Interdisciplinary Innovative Talents Foundation from Renmin Hospital of Wuhan University(No.JCRCFZ-2022-030)Guiding Projects of Traditional Chinese Medicine in 2023~2024 by Hubei Provincial Administration of Traditional Chinese Medicine(No.ZY2023F038)the support of the Core Facility of Wuhan University and the Large-scale Instrument and Equipment Sharing Foundation of Wuhan University。
文摘Effective treatment of subcutaneous tumors remains a focal point in cancer therapy.Photothermal therapy,a novel therapeutic approach,has emerged as a promising alternative,offering a less invasive option for the treatment of subcutaneous tumors.This study reports the exploration of novel supramolecular halogen-bonded organic frameworks(XOFs)based on[N…Br^(+)…N]halogen bonds through the ligand exchange strategy and their application in photothermal therapy.Through ligand exchange,XOF(Br)-TPy was successfully prepared,and its structure and properties were thoroughly characterized using NMR,XPS,FT-IR,and XRD techniques.Due to their cationic characteristics,these XOFs serve as effective carriers for the photothermal agent IR820.In vitro experiments demonstrated that the IR820@XOF(Br)-TPy composite exhibits excellent photothermal conversion efficiency under NIR irradiation,effectively inducing tumor cell ablation.Furthermore,in vivo studies confirmed the remarkable antitumor efficacy of the composite material in a subcutaneous tumor model.This work demonstrates that the ligand exchange strategy is a versatile and facile approach for constructing XOFs(Br)and provides a novel strategy for developing advanced photothermal therapeutic agents with significant application potential.
基金National Natural Science Foundation of China(Nos.21902023 and 21901252)Shanghai Pujiang Program,China(No.19PJ1400300)+1 种基金Professor of Special Appointment(Eastern Scholar),ChinaShanghai Institutions of Higher Education Fundamental Research Funds for the Central Universities,China(No.0900000155)。
文摘Catalytic reduction reactions using isopropanol(IPA)as a transfer hydrogenating agent are gaining significant attention due to the low cost and large-scale production of IPA.Traditional methods for carbon-carbon(C—C)bond construction often rely on expensive and scarce transition metal catalysts,raising concerns about sustainability and environmental impact.To address these challenges,we develop a bifunctional photocatalyst,phloroglucinol carbon quantum dot(PG-CQD).It facilitates catalytic transfer hydrogenation(CTH)with IPA as the hydrogen donor.PG-CQDs exhibit both dehydrogenation and reduction activities,enabling the formation of vicinal diols under mild conditions with visible light irradiation.We propose a CTH mechanism that has been successfully validated through experiments.The catalytic system demonstrates remarkable versatility,enabling the synthesis of various vicinal diols from diverseα-keto ester substrates with good or excellent yields.These findings offer a sustainable synthetic strategy that aligns with green chemistry principles and establish a promising pathway for the development of environmentally benign and energy-efficient organic transformations.
基金supported by the National Key R&D Program of China (No. 2018YFA0707300)the National Natural Science Foundation of China (No. 52374376)the Introduction Plan for High end Foreign Experts, China (No. G2023105001L)。
文摘Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding strength in titanium/stainless steel laminated composites were investigated.Results indicate that the hardened layer reduces the interfacial bonding strength from over 261 MPa to less than 204 MPa.During the cold roll-bonding process,the hardened layer fractures,leading to the formation of multi-scale cracks that are difficult for the stainless steel to fill.This not only hinders the development of an interlocking interface but also leads to the presence of numerous microcracks and hardened blocks along the nearly straight interface,consequently weakening the interfacial bonding strength.In metals with high work hardening rates,the conventional approach of enhancing interface interlocking and improving interfacial bonding strength by using a surface-hardened layer becomes less effective.
文摘The regioselective carbon-hydrogen bond functionalization reaction in atom-and step-economy holds significant potential for the late-stage elaboration of complex molecules and natural products.In recent years,the hydrogen atom transfer strategy involving radicals has garnered considerable attention from chemists due to its high chemoselectivity and regioselectivity.However,owing to the marginal differences in bond dissociation energies(BDEs)among C(sp^(3))—H bonds,hydrogen atom transfer reactions mediated by alkyl radicals remain less-developed.A copper-catalyzed sulfone-induced regioselective C(sp^(3))—H bond heteroarylation reaction was reported.This strategy utilizes theα-alkyl radical of sulfone as an intramolecular hydrogen abstraction reagent,enabling the regioselective formation of carbon-nitrogen bonds under copper catalysis.
