Interlocked covalent organic cages have aesthetic skeletons endowed with structural and topological complexity.Their self-assembly provides a unique possibility to mimic the hierarchical self-assembly of biomacromolec...Interlocked covalent organic cages have aesthetic skeletons endowed with structural and topological complexity.Their self-assembly provides a unique possibility to mimic the hierarchical self-assembly of biomacromolecules.In recent years,significant progresses in interlocked covalent organic cages have been witnessed.Different topological structures have been fabricated via various non-template induced methods,and diverse weak interactions are demonstrated to play critical roles in guiding the formation of interlocked structures.Therefore,this article systematically summarizes the recent advances in interlocked covalent organic cages,especially their design,synthesis,and self-assembly properties.Depending on different types of chemical reactions,irreversible and reversible reactions are separately introduced.In each section,proper monomer selection,critical topology design,key driving forces as well as detailed interlocked mechanisms for the formation of interlocked structures,and their self-assembly behaviors in single crystals are discussed detailedly.Finally,the challenge and future development of interlocked covalent organic cages are briefly prospected.展开更多
CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organ...CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organic frameworks(COFs)are porous crystalline materials formed by connecting organic monomers through covalent bonds.They have the characteristics of functional diversity and rich chemical properties.Their advantages,such as high porosity,a wide range of visible light absorption,and excellent charge separation efficiency,give them good potential in CO_(2)capture,separation,and conversion.Currently,Cu is a key metal in the catalytic CO_(2)reduction reaction(CO_(2)RR)for the preparation of high-value-added chemicals.The preparation of highly stable and large-pore Cu-based COFs using COFs as an ideal sacrificial template for loading Cu can be used to develop high-performance electrocatalysts and photocatalysts.In this review,we discuss the latest advancements in this field,including the development of various Cu-based COFs and their applications as catalysts for CO_(2)RR.Here,we mainly introduce the synthesis strategies,some important characterization information,and the applications of electrocatalytic and photocatalytic CO_(2)conversion using these previously reported Cu-based COFs.展开更多
High-sensitive quantitative determination of alpha-fetoprotein(AFP)is of crucial importance for early clinical diagnosis of cancers.Herein,an AuNPs-free electrochemical immunosensor(Ab1-Fc-COF)was prepared from a carb...High-sensitive quantitative determination of alpha-fetoprotein(AFP)is of crucial importance for early clinical diagnosis of cancers.Herein,an AuNPs-free electrochemical immunosensor(Ab1-Fc-COF)was prepared from a carboxylic group enriched COF by post-functionalization with detecting antibody(Ab1)and ferrocene(Fc),and used for electrochemical detection of AFP.Due to the small,homogeneous pore size of the COF,Ab1 with a big size was immobilized on the surface of the COF,while Fc with a small size was covalently modified both on the surface and in the pores of COF.The covalently immobilized Ab1 was quite stable and beneficial to specifically detect AFP biomarkers.Meanwhile,the enriched Fc molecules not only improved the conductivity of the COF,but also effectively transferred and amplified the electrochemical signal.This proposed immunosensor exhibited high sensitivity in detecting AFP with a detection limit of 0.39 pg/mL(S/N of 3:1)and a wide linear response range spanning from 1 pg/mL to 100 ng/mL when plotted against logarithmic concentrations.Furthermore,this immunosensor showed excellent selectivity,stability and reproducibility in the testing of real samples.This study presents an innovative prototype for construction of a precious metal-free,antibody-directly-immobilized,simple and stable electrochemical immunoprobe.展开更多
Polyimide-linkage covalent organic frameworks(PI-COFs),as a subclass of the COFs material family,featuring the unique combination of excellent thermal stability of polyimide,tunable pore sizes,as well as high crystall...Polyimide-linkage covalent organic frameworks(PI-COFs),as a subclass of the COFs material family,featuring the unique combination of excellent thermal stability of polyimide,tunable pore sizes,as well as high crystallinity and surface area of COFs,are expected to be a novel type of promising crystalline porous material with potential applications in adsorption and separation,catalysis,chemical sensing,and energy storage.Therefore,it is increasingly important to summarize polyimide-linkage in COFs and related applications and provide in-depth insight to accelerate future development.In this review,we offer a comprehensive overview of recent advancements in PI-COFs,emphasizing their synthesis methods,design principles and applications.Finally,our brief outlooks on the current challenges and future developments of PI-COFs are provided.Overall,this review aims to guide the recent and future development of PI-COFs.展开更多
Lysine-targeting reversible covalent inhibitors,particularly salicylaldehyde-based compounds such as the Food and Drug Administration(FDA)-approved drug Voxelotor,exhibit significant therapeutic potential but are limi...Lysine-targeting reversible covalent inhibitors,particularly salicylaldehyde-based compounds such as the Food and Drug Administration(FDA)-approved drug Voxelotor,exhibit significant therapeutic potential but are limited by challenges including instability and off-target effects.To overcome these limitations in kinase inhibitor A5,we devised a pH-responsive prodrug strategy by masking its reactive aldehyde group with an acid-labile hydrazone linkage and enhancing intracellular delivery through conjugation with FK506.The optimized prodrug demonstrated robust antitumor efficacy in K562 tumor-bearing mice.Furthermore,the incorporation of the photosensitizer chlorin e6(Ce6)led to the formation of self-assembled nanoparticles(AKNP),which not only improved physiological stability and prolonged tumor retention but also enabled light-triggered release of A5 in conjunction with photodynamic therapy(PDT).Our study thus presents a promising prodrug self-assembly strategy that combines the on-demand release of a novel lysine-targeting,reversible covalent kinase inhibitor with PDT in clinical cancer therapy.展开更多
The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Coval...The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Covalent organic frameworks(COFs) are ideal adsorbents for gold recovery owing to their large surface area,good stability,easily functionalized ability,periodic structures,and definitive nanopores.Herein,a cyano-functionalized COF(COF-CN) with high crystallinity was large-scale prepared under mild conditions for the recovery of gold.The introduction of cyano groups enable COF-CN to exhibit excellent gold recovery performance,which possesses fast adsorption kinetics,high cycling stability,and adsorption capacity up to 663.67 mg/g.Excitingly,COF-CN showed extremely high selectivity for gold ions,even in the presence of various competing cations and anions.The COF-CN maintained excellent selectivity and removal efficiency in gold recovery experiments from WEEE.The facile synthesis of COF-CN and its outstanding selectivity in actual samples make it an attractive opportunity for practical gold recovery.展开更多
Covalent organic frameworks(COFs)are considered promising catalysts for photocatalytic CO_(2)reduction reaction(pCO_(2)RR)due to facilitated regulations.However,the instability of COFs with dynamic reversible covalent...Covalent organic frameworks(COFs)are considered promising catalysts for photocatalytic CO_(2)reduction reaction(pCO_(2)RR)due to facilitated regulations.However,the instability of COFs with dynamic reversible covalent bonds and the limited modifiability of COFs with irreversible covalent bonds restricted the enhancement of the pCO_(2)RR performance.Herein,three phthalocyanine-based COFs with ether-linked,CoOP,CoPOP,and CoBOP,were successfully prepared via in situ polycondensation using modifiable bis-phthalonitrile.CoBOP achieved a record of syngas performance in pCO_(2)RR systems with photosensitizers and sacrificial agents(CO 83.7 mmol g^(-1)h^(-1)and H_254.7 mmol g^(-1)h^(-1)),surpassing most COF photocatalysts.Additionally,CoOP,CoPOP,and CoBOP exhibit stabilities in extreme environments owing to their irreversible covalent bonds.Experimental and density functional theory analyses confirm that the optimally matched the lowest unoccupied molecular orbital of the linking unit between the photosensitizer and active unit endowed Co BOP with the highest photoelectron transfer efficiency among the three catalysts,boosting its pCO_(2)RR activity.This work is highly instructive for designing COFs with structure-adjustable and irreversible covalent bonds.展开更多
Shape memory polymers used in 4D printing only had one permanent shape after molding,which limited their applications in requiring multiple reconstructions and multifunctional shapes.Furthermore,the inherent stability...Shape memory polymers used in 4D printing only had one permanent shape after molding,which limited their applications in requiring multiple reconstructions and multifunctional shapes.Furthermore,the inherent stability of the triazine ring structure within cyanate ester(CE)crosslinked networks after molding posed significant challenges for both recycling,repairing,and degradation of resin.To address these obstacles,dynamic thiocyanate ester(TCE)bonds and photocurable group were incorporated into CE,obtaining the recyclable and 3D printable CE covalent adaptable networks(CANs),denoted as PTCE1.5.This material exhibits a Young's modulus of 810 MPa and a tensile strength of 50.8 MPa.Notably,damaged printed PTCE1.5 objects can be readily repaired through reprinting and interface rejoining by thermal treatment.Leveraging the solid-state plasticity,PTCE1.5 also demonstrated attractive shape memory ability and permanent shape reconfigurability,enabling its reconfigurable 4D printing.The printed PTCE1.5 hinges and a main body were assembled into a deployable and retractable satellite model,validating its potential application as a controllable component in the aerospace field.Moreover,printed PTCE1.5 can be fully degraded into thiol-modified intermediate products.Overall,this material not only enriches the application range of CE resin,but also provides a reliable approach to addressing environmental issue.展开更多
Covalent organic framework ionomers enable synergistic efficient transport of protons and oxygen in medium-temperature proton exchange membrane fuel cells Proton exchange membrane fuel cells(PEMFCs),as clean and effic...Covalent organic framework ionomers enable synergistic efficient transport of protons and oxygen in medium-temperature proton exchange membrane fuel cells Proton exchange membrane fuel cells(PEMFCs),as clean and efficient energy technologies,are constrained in their performance enhancement by the sluggish oxygen reduction reaction(ORR)kinetics at the cathode,anode CO poisoning(e.g.,from methanol crossover)and intricate water management dilemmas[1].展开更多
Photosynthesis of hydrogen peroxide(H_(2)O_(2))via oxygen reduction reaction(ORR)and water oxidation reaction(WOR)pathways requires controlled formation of radical intermediates.However,achieving precise control over ...Photosynthesis of hydrogen peroxide(H_(2)O_(2))via oxygen reduction reaction(ORR)and water oxidation reaction(WOR)pathways requires controlled formation of radical intermediates.However,achieving precise control over radical formation in metal-free catalysts remains challenging.Herein,we report a fluorinated COF(Kf-F-COF)featuring framework-bound carbonyl groups as intrinsic radical-generating sites for efficient dual-channel H_(2)O_(2)photosynthesis.This design enables the simultaneous activation of O_(2)and H_(2)O through radical-mediated hydrogen atom transfer processes.Mechanistic studies reveal that fluorination enhances the electron affinity of the carbonyl sites,facilitates diradical formation,and lowers the energy barriers of key reaction steps.As a result,Kf-F-COF achieves a high H_(2)O_(2)production rate of 6.42 mmol g^(-1)h^(-1)and long-term stability under natural sunlight and seawater conditions.This work presents a frameworkcentered radical strategy for dual-pathway H_(2)O_(2)photosynthesis and offers mechanistic insights into regulating COF-based photocatalysts.展开更多
Ketamine is recognized for its rapid-onset and longer-term antidepressant actions,but the molecular mechanisms underlying these outcomes are not fully comprehended.Our prior research indicated that the covalent modifi...Ketamine is recognized for its rapid-onset and longer-term antidepressant actions,but the molecular mechanisms underlying these outcomes are not fully comprehended.Our prior research indicated that the covalent modification of ketamine or its metabolites on hippocampus protein may contribute to its antidepressant actions,however,the specific molecular mechanisms are yet to be elucidated.In this research,we employed chemical proteomics approaches to investigate comprehensively the covalent interactions between ketamine or its metabolites and hippocampus proteins in vivo.We discovered that ketamine could covalently bind to lysine residues on proteins after bioactivation,complementing our previous finding of cysteine modification.Moreover,comprehensive chemical proteomics analysis revealed that 21 proteins were modified by ketamine or its metabolites in mouse hippocampus.Finally,bioinformatics analysis revealed that ketamine exerted antidepressant effects via multi-target and multi-pathway mechanism especially involved in synaptic plasticity.These findings offer a novel perspective for understanding the underlying molecular mechanism of antidepressant action.展开更多
Covalent organic frameworks have emerged as a hot spot in the field of photocatalysis due to their excellent structural tunability,high specific surface area,high porosity,and good chemical stability.Specifically,they...Covalent organic frameworks have emerged as a hot spot in the field of photocatalysis due to their excellent structural tunability,high specific surface area,high porosity,and good chemical stability.Specifically,they exhibit distinctive optoelectronic features by integrating different molecular building blocks with appropriate links,constructing an π-conjugated system,or introducing electron donor–acceptor units into the conjugated framework.The reasonably adjusted band structure yields excellent photocatalytic activity of covalent organic framework materials.展开更多
Zinc-ion batteries(ZIBs)are inexpensive and safe,but side reactions on the Zn anode and Zn dendrite growth hinder their practical applications.In this study,1,3,5-triformylphloroglycerol(Tp)and various diamine monomer...Zinc-ion batteries(ZIBs)are inexpensive and safe,but side reactions on the Zn anode and Zn dendrite growth hinder their practical applications.In this study,1,3,5-triformylphloroglycerol(Tp)and various diamine monomers(p-phenylenediamine(Pa),benzidine(BD),and 4,4"-diamino-p-terphenyl(DATP))were used to synthesize a series of two-dimensional covalent-organic frameworks(COFs).The resulting COFs were named TpPa,TpBD,and TpDATP,respectively,and they showed uniform zincophilic sites,different pore sizes,and high Young's moduli on the Zn anode.Among them,TpPa and TpBD showed lower surface work functions and higher ion transfer numbers,which were conducive to uniform galvanizing/stripping zinc and inhibited dendrite growth.Theoretical calculations showed that TpPa and TpBD had wider negative potential region and greater adsorption capacity for Zn2+than TpDATP,providing more electron donor sites to coordinate with Zn^(2+).Symmetric cells protected by TpPa and TpBD stably cycled for more than 2300 h,whereas TpDATP@Zn and the bare zinc symmetric cells failed after around 150 and200 h.The full cells containing TpPa and TpBD modification layers also showed excellent cycling capacity at 1 A/g.This study provides comprehensive insights into the construction of highly reversible Zn anodes via COF modification layers for advanced rechargeable ZIBs.展开更多
The light-driven CO_(2)reduction reaction(CO_(2)RR)to CO is a very effective way to address global warming.To avoid competition with water photolysis,metal-free gas-solid CO_(2)RR catalysts should be investigated.Cova...The light-driven CO_(2)reduction reaction(CO_(2)RR)to CO is a very effective way to address global warming.To avoid competition with water photolysis,metal-free gas-solid CO_(2)RR catalysts should be investigated.Covalent organic frameworks(COFs)offer a promising approach for CO_(2)transformation but lack high efficiency and selectivity in the absence of metals.Here,we have incorporated a pyridine nitrogen component into the imine-COF conjugated structure(Tp Pym).This innovative system has set a record of producing a CO yield of 1565μmol g^(-1)within 6 h.The soft X-ray absorption fine structure measurement proves that Tp Pym has both better conjugation and electron cloud enrichment.The electronic structure distribution delays the charge-carrier recombination,as evidenced by femtosecond transient absorption spectroscopy.The energy band diagram and theoretical calculation show that the conduction-band potential of Tp Pym is lower and the reduction reaction of CO_(2)to CO is more likely to occur.展开更多
Covalent organic frameworks(COFs)have great potential as adsorbents due to their customizable functionality,low density and high porosity.However,COFs powder exists with poor processing and recycling performance.Moreo...Covalent organic frameworks(COFs)have great potential as adsorbents due to their customizable functionality,low density and high porosity.However,COFs powder exists with poor processing and recycling performance.Moreover,due to the accumulation of COFs nanoparticles,it is not conducive to the full utilization of their surface functional groups.Currently,the strategy of COFs assembling into aerogel can be a good solution to this problem.Herein,we successfully synthesize composite aerogels(CSR)by in-situ self-assembly of two-dimensional COFs and graphene based on crosslinking of sodium alginate.Sodium alginate in the composite improves the mechanical properties of the aerogel,and graphene provides a template for the in-situ growth of COFs.Impressively,CSR aerogels with different COFs and sizes can be prepared by changing the moiety of the ligand and modulating the addition amount of COFs.The prepared CSR aerogels exhibit porous,low density,good processability and good mechanical properties.Among them,the density of CSR-N-1.6 is only 5 mg/cm3,which is the lowest density among the reported COF aerogels so far.Due to these remarkable properties,CSR aerogels perform excellent adsorption and recycling properties for the efficient and rapid removal of organic pollutants(organic dyes and antibiotics)from polluted water.In addition,it is also possible to visually recognize the presence of antibiotics by fluorescence detection.This work not only provides a new strategy for synthesizing COF aerogels,but also accelerates the practical application of COF aerogels and contributes to environmental remediation.展开更多
Prostaglandin E2(PGE2) serves as the ultimate mediator of fever induced by infiammatory factors. In contrast to cyclooxygenase inhibitors that suppress arachidonic acid metabolism, antipyretic herbs possess a well-est...Prostaglandin E2(PGE2) serves as the ultimate mediator of fever induced by infiammatory factors. In contrast to cyclooxygenase inhibitors that suppress arachidonic acid metabolism, antipyretic herbs possess a well-established clinical history in effectively managing fever. However, the specific mechanisms underlying their efficacy remain unclear. Following the screening for lead compounds that inhibit PGE2from antipyretic herbs, alkynylated active molecule probes were designed and synthesized to track and identify potential targets. The target investigation revealed that three antipyretic compounds, namely cinnamaldehyde, 2,4-decadienal, and perillaldehyde, containing α,β-unsaturated aldehyde groups irreversibly targeted the microsomal PGES1-TM4 helix(m PGES1-TM4) at Ser139. This specific interaction effectually inhibited PGE2 production in the cerebral vasculature, leading to exert potent antipyretic effects.α,β-Unsaturated aldehydes targeting m PGES1-TM4 offer a new approach for antipyretic effects with significant potential for various applications.展开更多
A sp^(2) carbon-conjugated covalent organic framework (BDATN) was modified through γ-ray radiation reduction and subsequent acidification with hydrochloric acid to yield a novel functional COF (named rBDATN-HCl) for ...A sp^(2) carbon-conjugated covalent organic framework (BDATN) was modified through γ-ray radiation reduction and subsequent acidification with hydrochloric acid to yield a novel functional COF (named rBDATN-HCl) for Cr(Ⅵ) removal.The morphology and structure of rBDATN-HCl were analyzed and identified by SEM,FTIR,XRD and solid-state13C NMR.It is found that the active functional groups,such as hydroxyl and amide,were introduced into BDATN after radiation reduction and acidification.The prepared rBDATN-HCl demonstrates a photocatalytic reduction removal rate of Cr(Ⅵ) above 99%after 60min of illumination with a solid-liquid ratio of 0.5 mg/mL,showing outstanding performance,which is attributed to the increase of dispersibility and adsorption sites of r BDATN-HCl.In comparison to the cBDATN-HCl synthesized with chemical reduction,rBDATN-HCl exhibits a better photoreduction performance for Cr(Ⅵ),demonstrating the advantages of radiation preparation of rBDATN-HCl.It is expected that more functionalized sp^(2) carbon-conjugated COFs could be obtained by this radiation-induced reduction strategy.展开更多
We have developed a novel S-scheme heterojunction photocatalyst for the photocatalytic production of hydrogen peroxide(H_(2)O_(2))via a two-electron(2e^(-))oxygen reduction reaction.This S-scheme heterojunction Tph-Dh...We have developed a novel S-scheme heterojunction photocatalyst for the photocatalytic production of hydrogen peroxide(H_(2)O_(2))via a two-electron(2e^(-))oxygen reduction reaction.This S-scheme heterojunction Tph-Dha-COF@Nb_(2)C was fabricated via the in-situ solvothermal growth of Tph-Dha-COF nanostructures on amino-functionalized Nb_(2)C MXene nanoflakes(Nb_(2)C-NH_(2)).The integration of Nb_(2)C significantly extended the visible light absorption of Tph-Dha-COF into the near-infrared region for photocatalytic H_(2)O_(2) production.The Tph-Dha-COF@Nb_(2)C composite demonstrated efficient charge separation,rapid electron transfer,and enhanced oxygen adsorption.Consequently,the Tph-Dha-COF@Nb_(2)C heterojunction exhibited a high H_(2)O_(2) production rate of 1833μmol g^(-1) h^(-1) without sacrificial agents.In-situ Fourier transformed infrared spectroscopy and density functional theory calculations revealed the photocatalytic H_(2)O_(2) production mechanism.The generated H_(2)O_(2) demonstrated enhanced antibacterial activity.This work presents the first application of Nb_(2)C in the photocatalytic synthesis of H_(2)O_(2) and provides a novel strategy for constructing COF-based heterojunctions for photocatalytic H_(2)O_(2) generation and wastewater treatment.展开更多
Controlling the intermolecular charge transfer between co-reactants and emitters represents a promising strategy for elucidating the luminescent mechanism and enhancing the efficiency of electrochemiluminescence(ECL)s...Controlling the intermolecular charge transfer between co-reactants and emitters represents a promising strategy for elucidating the luminescent mechanism and enhancing the efficiency of electrochemiluminescence(ECL)systems.Herein,a self-enhanced ECL microreactor was prepared by bimetallic Zn-/Co-porphyrin covalent organic framework(COF_(Zn/CoP-Ph)@MWCNTs),in which co-reaction accelerators(cobalt porphyrin)and luminophores(zinc porphyrin)were precisely woven into the COFs skeleton via covalent bonds.Owing to the unique topological structure,the rational arrangement of coreaction accelerators and luminophores in a spatially confined environment effectively controlled the intermolecular charge transfer.And the spatially restricted environment formed by the COF_(Zn/CoP-Ph)@MWCNTs microreactor avoided the problem of disordered diffusion of active intermediates,leading to an enhanced ECL response.Thanks to the synergistic impacts of the factors above,the ECL intensity of the bimetallic COF_(Zn/CoP-Ph)@MWCNTs was 10.2-folds stronger than the zinc porphyrin monomer.Therefore,the self-enhanced ECL sensor was constructed for miRNA-155 detection via an“on-off”ECL quenching mechanism and a cycling amplification strategy,displayed a broad linear range(0.10 pM–10μM)and a low limit of detection(0.51 fM).In brief,studying the programmable structures and tunable electronic paths of high-performance COF materials would provide good access for the engineering self-enhanced ECL system and the construction of ultrasensitive sensors.展开更多
The advancement of functional adhesives featuring recyclable and repairable properties is of great significance in interfacial science and engineering.Herein,a series of high-strength,recyclable fluorine-containing ad...The advancement of functional adhesives featuring recyclable and repairable properties is of great significance in interfacial science and engineering.Herein,a series of high-strength,recyclable fluorine-containing adhesives(ESOx-FPF)were designed and synthesized by crosslinking two prepolymers,FPF-B(derived from side-chain fluorinated diol,isocyanate,and aminoboric acid)and ESO-B(synthesized from biobased epoxy soybean oil and aminoboric acid),through dynamic boro-oxygen bonds.The resulting adhesive exhibited an optimal tensile strength of 42 MPa and the shear strength on steel plates reached as high as 3.89 MPa.More importantly,benefiting from the dynamic reversibility of the boron-oxygen bonds along with the hydrogen bonds interaction,ESOx-FPF can be welded with the assistance of solvents and recycled for multiple cycles.The outstanding healing efficiency and excellent reprocessability of these functional adhesives were confirmed by mechanical testing.Moreover,the as-prepared adhesives demonstrated universal and remarkable adhesion to various substrates,such as aromatic polyamide,aluminum plates and polycarbonate,meanwhile,they could be easily disassembled and recycled using ethanol without damaging the substrates surface.This study not only provides a simple strategy for the synthesis of eco-friendly adhesives with weldable and recyclable properties,but also sheds light on the development of other functional materials utilizing dynamic covalent chemistry.展开更多
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission (No.KJQN202400807)Natural Science Foundation of Shanghai (No.23ZR1419600)。
文摘Interlocked covalent organic cages have aesthetic skeletons endowed with structural and topological complexity.Their self-assembly provides a unique possibility to mimic the hierarchical self-assembly of biomacromolecules.In recent years,significant progresses in interlocked covalent organic cages have been witnessed.Different topological structures have been fabricated via various non-template induced methods,and diverse weak interactions are demonstrated to play critical roles in guiding the formation of interlocked structures.Therefore,this article systematically summarizes the recent advances in interlocked covalent organic cages,especially their design,synthesis,and self-assembly properties.Depending on different types of chemical reactions,irreversible and reversible reactions are separately introduced.In each section,proper monomer selection,critical topology design,key driving forces as well as detailed interlocked mechanisms for the formation of interlocked structures,and their self-assembly behaviors in single crystals are discussed detailedly.Finally,the challenge and future development of interlocked covalent organic cages are briefly prospected.
文摘CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organic frameworks(COFs)are porous crystalline materials formed by connecting organic monomers through covalent bonds.They have the characteristics of functional diversity and rich chemical properties.Their advantages,such as high porosity,a wide range of visible light absorption,and excellent charge separation efficiency,give them good potential in CO_(2)capture,separation,and conversion.Currently,Cu is a key metal in the catalytic CO_(2)reduction reaction(CO_(2)RR)for the preparation of high-value-added chemicals.The preparation of highly stable and large-pore Cu-based COFs using COFs as an ideal sacrificial template for loading Cu can be used to develop high-performance electrocatalysts and photocatalysts.In this review,we discuss the latest advancements in this field,including the development of various Cu-based COFs and their applications as catalysts for CO_(2)RR.Here,we mainly introduce the synthesis strategies,some important characterization information,and the applications of electrocatalytic and photocatalytic CO_(2)conversion using these previously reported Cu-based COFs.
基金the Natural Science Foundation of ZhejiangProvince(No.LZ24B020005)the National Natural Science Foundation of China(No.22071040)for financial support.
文摘High-sensitive quantitative determination of alpha-fetoprotein(AFP)is of crucial importance for early clinical diagnosis of cancers.Herein,an AuNPs-free electrochemical immunosensor(Ab1-Fc-COF)was prepared from a carboxylic group enriched COF by post-functionalization with detecting antibody(Ab1)and ferrocene(Fc),and used for electrochemical detection of AFP.Due to the small,homogeneous pore size of the COF,Ab1 with a big size was immobilized on the surface of the COF,while Fc with a small size was covalently modified both on the surface and in the pores of COF.The covalently immobilized Ab1 was quite stable and beneficial to specifically detect AFP biomarkers.Meanwhile,the enriched Fc molecules not only improved the conductivity of the COF,but also effectively transferred and amplified the electrochemical signal.This proposed immunosensor exhibited high sensitivity in detecting AFP with a detection limit of 0.39 pg/mL(S/N of 3:1)and a wide linear response range spanning from 1 pg/mL to 100 ng/mL when plotted against logarithmic concentrations.Furthermore,this immunosensor showed excellent selectivity,stability and reproducibility in the testing of real samples.This study presents an innovative prototype for construction of a precious metal-free,antibody-directly-immobilized,simple and stable electrochemical immunoprobe.
基金supported by the National Key R&D Program of China(No.2023YFA1507204)National Natural Science Foundation ofChina(Nos.22475074,22171139,22225109,22302055)+4 种基金Natural Science Foundation of Guangdong Province(No.2023B1515020076)Key Scientific Research Project Plan of Colleges and Universities of Henan Province(No.24B150004)The Double Thousand Talents Plan of Jiangxi Province(No.jxsq2023102003)Project supported by the Guangdong Provincial Key Laboratory of Carbon Dioxide Resource Utilization(No.2024B121201001)Project supportedby the Major Research plan of the National Natural Science Foundation of China(No.92461310).
文摘Polyimide-linkage covalent organic frameworks(PI-COFs),as a subclass of the COFs material family,featuring the unique combination of excellent thermal stability of polyimide,tunable pore sizes,as well as high crystallinity and surface area of COFs,are expected to be a novel type of promising crystalline porous material with potential applications in adsorption and separation,catalysis,chemical sensing,and energy storage.Therefore,it is increasingly important to summarize polyimide-linkage in COFs and related applications and provide in-depth insight to accelerate future development.In this review,we offer a comprehensive overview of recent advancements in PI-COFs,emphasizing their synthesis methods,design principles and applications.Finally,our brief outlooks on the current challenges and future developments of PI-COFs are provided.Overall,this review aims to guide the recent and future development of PI-COFs.
基金supported by the grants from National Key R&D Program of China(No.2022YFA1104800)Shenzhen Science and Technology Program(No.JCYJ20210324124214038)+4 种基金National Natural Science Foundation of China(Nos.52072418,82300016)Natural Science Foundation of Guangdong Province(No.2023A1515140072)Shenzhen Key Laboratory of Neural Cell Reprogramming and Drug Research,Social Development Science and Technology Key Project of Dongguan(No.20231800940512)the National Medical Research Council(NMRC,No.23-0740-A0001)the Ministry of Education(MOE,No.T2EP10222-0002)of Singapore.
文摘Lysine-targeting reversible covalent inhibitors,particularly salicylaldehyde-based compounds such as the Food and Drug Administration(FDA)-approved drug Voxelotor,exhibit significant therapeutic potential but are limited by challenges including instability and off-target effects.To overcome these limitations in kinase inhibitor A5,we devised a pH-responsive prodrug strategy by masking its reactive aldehyde group with an acid-labile hydrazone linkage and enhancing intracellular delivery through conjugation with FK506.The optimized prodrug demonstrated robust antitumor efficacy in K562 tumor-bearing mice.Furthermore,the incorporation of the photosensitizer chlorin e6(Ce6)led to the formation of self-assembled nanoparticles(AKNP),which not only improved physiological stability and prolonged tumor retention but also enabled light-triggered release of A5 in conjunction with photodynamic therapy(PDT).Our study thus presents a promising prodrug self-assembly strategy that combines the on-demand release of a novel lysine-targeting,reversible covalent kinase inhibitor with PDT in clinical cancer therapy.
基金financially supported by the National Natural Science Foundation of China (No.51972302)。
文摘The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Covalent organic frameworks(COFs) are ideal adsorbents for gold recovery owing to their large surface area,good stability,easily functionalized ability,periodic structures,and definitive nanopores.Herein,a cyano-functionalized COF(COF-CN) with high crystallinity was large-scale prepared under mild conditions for the recovery of gold.The introduction of cyano groups enable COF-CN to exhibit excellent gold recovery performance,which possesses fast adsorption kinetics,high cycling stability,and adsorption capacity up to 663.67 mg/g.Excitingly,COF-CN showed extremely high selectivity for gold ions,even in the presence of various competing cations and anions.The COF-CN maintained excellent selectivity and removal efficiency in gold recovery experiments from WEEE.The facile synthesis of COF-CN and its outstanding selectivity in actual samples make it an attractive opportunity for practical gold recovery.
基金financially supported by the Innovation Capability Support Program of Shaanxi—Science and Technology Innovation Team Project(No.2025RS-CXTD-024)the Fundamental Research Foundation of SHCCIG New Materials Technology Research Institute Co.,Ltd(No.D5204230171)+3 种基金the Fundamental Research Funds for the Central Universities(G2025KY05240)the Natural Science Basic Research Program of Shaanxi(Program No.2024JC-YBQN-0073)the Fundamental Research Funds for the Central Universities(No.D5000250204)Young Talent Fund of Association for Science and Technology in Shaanxi(No.20230101)。
文摘Covalent organic frameworks(COFs)are considered promising catalysts for photocatalytic CO_(2)reduction reaction(pCO_(2)RR)due to facilitated regulations.However,the instability of COFs with dynamic reversible covalent bonds and the limited modifiability of COFs with irreversible covalent bonds restricted the enhancement of the pCO_(2)RR performance.Herein,three phthalocyanine-based COFs with ether-linked,CoOP,CoPOP,and CoBOP,were successfully prepared via in situ polycondensation using modifiable bis-phthalonitrile.CoBOP achieved a record of syngas performance in pCO_(2)RR systems with photosensitizers and sacrificial agents(CO 83.7 mmol g^(-1)h^(-1)and H_254.7 mmol g^(-1)h^(-1)),surpassing most COF photocatalysts.Additionally,CoOP,CoPOP,and CoBOP exhibit stabilities in extreme environments owing to their irreversible covalent bonds.Experimental and density functional theory analyses confirm that the optimally matched the lowest unoccupied molecular orbital of the linking unit between the photosensitizer and active unit endowed Co BOP with the highest photoelectron transfer efficiency among the three catalysts,boosting its pCO_(2)RR activity.This work is highly instructive for designing COFs with structure-adjustable and irreversible covalent bonds.
基金supported by the National Natural Science Foundation of China(Nos.52473080,52403167 and 52173079)the Fundamental Research Funds for the Central Universities(Nos.xtr052023001 and xzy012023037)+1 种基金the Postdoctoral Research Project of Shaanxi Province(No.2024BSHSDZZ054)the Shaanxi Laboratory of Advanced Materials(No.2024ZY-JCYJ-04-12).
文摘Shape memory polymers used in 4D printing only had one permanent shape after molding,which limited their applications in requiring multiple reconstructions and multifunctional shapes.Furthermore,the inherent stability of the triazine ring structure within cyanate ester(CE)crosslinked networks after molding posed significant challenges for both recycling,repairing,and degradation of resin.To address these obstacles,dynamic thiocyanate ester(TCE)bonds and photocurable group were incorporated into CE,obtaining the recyclable and 3D printable CE covalent adaptable networks(CANs),denoted as PTCE1.5.This material exhibits a Young's modulus of 810 MPa and a tensile strength of 50.8 MPa.Notably,damaged printed PTCE1.5 objects can be readily repaired through reprinting and interface rejoining by thermal treatment.Leveraging the solid-state plasticity,PTCE1.5 also demonstrated attractive shape memory ability and permanent shape reconfigurability,enabling its reconfigurable 4D printing.The printed PTCE1.5 hinges and a main body were assembled into a deployable and retractable satellite model,validating its potential application as a controllable component in the aerospace field.Moreover,printed PTCE1.5 can be fully degraded into thiol-modified intermediate products.Overall,this material not only enriches the application range of CE resin,but also provides a reliable approach to addressing environmental issue.
文摘Covalent organic framework ionomers enable synergistic efficient transport of protons and oxygen in medium-temperature proton exchange membrane fuel cells Proton exchange membrane fuel cells(PEMFCs),as clean and efficient energy technologies,are constrained in their performance enhancement by the sluggish oxygen reduction reaction(ORR)kinetics at the cathode,anode CO poisoning(e.g.,from methanol crossover)and intricate water management dilemmas[1].
基金supported by the National Key R&D Program of China(2022YFA1502902)the National Natural Science Foundation of China(22201209,22271218,22071182,21931007,22301235)+1 种基金the Shaanxi Province Young Talent Support Plan(2023SYJ28)the Start-Up Funding of Tianjin University and Xi’an Jiaotong University。
文摘Photosynthesis of hydrogen peroxide(H_(2)O_(2))via oxygen reduction reaction(ORR)and water oxidation reaction(WOR)pathways requires controlled formation of radical intermediates.However,achieving precise control over radical formation in metal-free catalysts remains challenging.Herein,we report a fluorinated COF(Kf-F-COF)featuring framework-bound carbonyl groups as intrinsic radical-generating sites for efficient dual-channel H_(2)O_(2)photosynthesis.This design enables the simultaneous activation of O_(2)and H_(2)O through radical-mediated hydrogen atom transfer processes.Mechanistic studies reveal that fluorination enhances the electron affinity of the carbonyl sites,facilitates diradical formation,and lowers the energy barriers of key reaction steps.As a result,Kf-F-COF achieves a high H_(2)O_(2)production rate of 6.42 mmol g^(-1)h^(-1)and long-term stability under natural sunlight and seawater conditions.This work presents a frameworkcentered radical strategy for dual-pathway H_(2)O_(2)photosynthesis and offers mechanistic insights into regulating COF-based photocatalysts.
基金supported by the Science and Technology Development Fund,Macao SAR(File no.0001/2020/AKP and 006/2023/SKL)the Youth Fund Project of National Natural Science Foundation of China(Grant No.22406065)。
文摘Ketamine is recognized for its rapid-onset and longer-term antidepressant actions,but the molecular mechanisms underlying these outcomes are not fully comprehended.Our prior research indicated that the covalent modification of ketamine or its metabolites on hippocampus protein may contribute to its antidepressant actions,however,the specific molecular mechanisms are yet to be elucidated.In this research,we employed chemical proteomics approaches to investigate comprehensively the covalent interactions between ketamine or its metabolites and hippocampus proteins in vivo.We discovered that ketamine could covalently bind to lysine residues on proteins after bioactivation,complementing our previous finding of cysteine modification.Moreover,comprehensive chemical proteomics analysis revealed that 21 proteins were modified by ketamine or its metabolites in mouse hippocampus.Finally,bioinformatics analysis revealed that ketamine exerted antidepressant effects via multi-target and multi-pathway mechanism especially involved in synaptic plasticity.These findings offer a novel perspective for understanding the underlying molecular mechanism of antidepressant action.
基金financial support from National Natural Science Foundation of China(52272287,22268003)Yunnan Fundamental Research Projects(202305AF150116,202301AT070027)。
文摘Covalent organic frameworks have emerged as a hot spot in the field of photocatalysis due to their excellent structural tunability,high specific surface area,high porosity,and good chemical stability.Specifically,they exhibit distinctive optoelectronic features by integrating different molecular building blocks with appropriate links,constructing an π-conjugated system,or introducing electron donor–acceptor units into the conjugated framework.The reasonably adjusted band structure yields excellent photocatalytic activity of covalent organic framework materials.
基金financially supported by the National Natural Science Foundation of China(62464010)Spring City Plan-Special Program for Young Talents(K202005007)+3 种基金Yunnan Talents Support Plan for Yong Talents(XDYC-QNRC-2022-0482)Yunnan Local Colleges Applied Basic Research Projects(202101BA070001-138)Key Laboratory of Artificial Microstructures in Yunnan Higher EducationFrontier Research Team of Kunming University 2023。
文摘Zinc-ion batteries(ZIBs)are inexpensive and safe,but side reactions on the Zn anode and Zn dendrite growth hinder their practical applications.In this study,1,3,5-triformylphloroglycerol(Tp)and various diamine monomers(p-phenylenediamine(Pa),benzidine(BD),and 4,4"-diamino-p-terphenyl(DATP))were used to synthesize a series of two-dimensional covalent-organic frameworks(COFs).The resulting COFs were named TpPa,TpBD,and TpDATP,respectively,and they showed uniform zincophilic sites,different pore sizes,and high Young's moduli on the Zn anode.Among them,TpPa and TpBD showed lower surface work functions and higher ion transfer numbers,which were conducive to uniform galvanizing/stripping zinc and inhibited dendrite growth.Theoretical calculations showed that TpPa and TpBD had wider negative potential region and greater adsorption capacity for Zn2+than TpDATP,providing more electron donor sites to coordinate with Zn^(2+).Symmetric cells protected by TpPa and TpBD stably cycled for more than 2300 h,whereas TpDATP@Zn and the bare zinc symmetric cells failed after around 150 and200 h.The full cells containing TpPa and TpBD modification layers also showed excellent cycling capacity at 1 A/g.This study provides comprehensive insights into the construction of highly reversible Zn anodes via COF modification layers for advanced rechargeable ZIBs.
基金supported by the National Natural Science Foundation of China(Nos.22375031,22202037,22472023)the Fundamental Research Funds for the Central Universities(Nos.2412023YQ001,2412023QD019,2412024QD014)+1 种基金supported by grants from the seventh batch of Jilin Province Youth Science and Technology Talent Lifting Project(No.QT202305)Science and Technology Development Plan Project of Jilin Province,China(No.20240101192JC)。
文摘The light-driven CO_(2)reduction reaction(CO_(2)RR)to CO is a very effective way to address global warming.To avoid competition with water photolysis,metal-free gas-solid CO_(2)RR catalysts should be investigated.Covalent organic frameworks(COFs)offer a promising approach for CO_(2)transformation but lack high efficiency and selectivity in the absence of metals.Here,we have incorporated a pyridine nitrogen component into the imine-COF conjugated structure(Tp Pym).This innovative system has set a record of producing a CO yield of 1565μmol g^(-1)within 6 h.The soft X-ray absorption fine structure measurement proves that Tp Pym has both better conjugation and electron cloud enrichment.The electronic structure distribution delays the charge-carrier recombination,as evidenced by femtosecond transient absorption spectroscopy.The energy band diagram and theoretical calculation show that the conduction-band potential of Tp Pym is lower and the reduction reaction of CO_(2)to CO is more likely to occur.
基金the financial support provided by the National Natural Science Foundation of China(Nos.22175094,21971113)。
文摘Covalent organic frameworks(COFs)have great potential as adsorbents due to their customizable functionality,low density and high porosity.However,COFs powder exists with poor processing and recycling performance.Moreover,due to the accumulation of COFs nanoparticles,it is not conducive to the full utilization of their surface functional groups.Currently,the strategy of COFs assembling into aerogel can be a good solution to this problem.Herein,we successfully synthesize composite aerogels(CSR)by in-situ self-assembly of two-dimensional COFs and graphene based on crosslinking of sodium alginate.Sodium alginate in the composite improves the mechanical properties of the aerogel,and graphene provides a template for the in-situ growth of COFs.Impressively,CSR aerogels with different COFs and sizes can be prepared by changing the moiety of the ligand and modulating the addition amount of COFs.The prepared CSR aerogels exhibit porous,low density,good processability and good mechanical properties.Among them,the density of CSR-N-1.6 is only 5 mg/cm3,which is the lowest density among the reported COF aerogels so far.Due to these remarkable properties,CSR aerogels perform excellent adsorption and recycling properties for the efficient and rapid removal of organic pollutants(organic dyes and antibiotics)from polluted water.In addition,it is also possible to visually recognize the presence of antibiotics by fluorescence detection.This work not only provides a new strategy for synthesizing COF aerogels,but also accelerates the practical application of COF aerogels and contributes to environmental remediation.
基金supported by the National Key R&D Program of China (Nos. 2022YFC3500800 and 2022YFC3500805)。
文摘Prostaglandin E2(PGE2) serves as the ultimate mediator of fever induced by infiammatory factors. In contrast to cyclooxygenase inhibitors that suppress arachidonic acid metabolism, antipyretic herbs possess a well-established clinical history in effectively managing fever. However, the specific mechanisms underlying their efficacy remain unclear. Following the screening for lead compounds that inhibit PGE2from antipyretic herbs, alkynylated active molecule probes were designed and synthesized to track and identify potential targets. The target investigation revealed that three antipyretic compounds, namely cinnamaldehyde, 2,4-decadienal, and perillaldehyde, containing α,β-unsaturated aldehyde groups irreversibly targeted the microsomal PGES1-TM4 helix(m PGES1-TM4) at Ser139. This specific interaction effectually inhibited PGE2 production in the cerebral vasculature, leading to exert potent antipyretic effects.α,β-Unsaturated aldehydes targeting m PGES1-TM4 offer a new approach for antipyretic effects with significant potential for various applications.
基金supported by the National Natural Science Foundation of China(No.U2067212)the National Science Fund for Distinguished Young Scholars(No.21925603).
文摘A sp^(2) carbon-conjugated covalent organic framework (BDATN) was modified through γ-ray radiation reduction and subsequent acidification with hydrochloric acid to yield a novel functional COF (named rBDATN-HCl) for Cr(Ⅵ) removal.The morphology and structure of rBDATN-HCl were analyzed and identified by SEM,FTIR,XRD and solid-state13C NMR.It is found that the active functional groups,such as hydroxyl and amide,were introduced into BDATN after radiation reduction and acidification.The prepared rBDATN-HCl demonstrates a photocatalytic reduction removal rate of Cr(Ⅵ) above 99%after 60min of illumination with a solid-liquid ratio of 0.5 mg/mL,showing outstanding performance,which is attributed to the increase of dispersibility and adsorption sites of r BDATN-HCl.In comparison to the cBDATN-HCl synthesized with chemical reduction,rBDATN-HCl exhibits a better photoreduction performance for Cr(Ⅵ),demonstrating the advantages of radiation preparation of rBDATN-HCl.It is expected that more functionalized sp^(2) carbon-conjugated COFs could be obtained by this radiation-induced reduction strategy.
文摘We have developed a novel S-scheme heterojunction photocatalyst for the photocatalytic production of hydrogen peroxide(H_(2)O_(2))via a two-electron(2e^(-))oxygen reduction reaction.This S-scheme heterojunction Tph-Dha-COF@Nb_(2)C was fabricated via the in-situ solvothermal growth of Tph-Dha-COF nanostructures on amino-functionalized Nb_(2)C MXene nanoflakes(Nb_(2)C-NH_(2)).The integration of Nb_(2)C significantly extended the visible light absorption of Tph-Dha-COF into the near-infrared region for photocatalytic H_(2)O_(2) production.The Tph-Dha-COF@Nb_(2)C composite demonstrated efficient charge separation,rapid electron transfer,and enhanced oxygen adsorption.Consequently,the Tph-Dha-COF@Nb_(2)C heterojunction exhibited a high H_(2)O_(2) production rate of 1833μmol g^(-1) h^(-1) without sacrificial agents.In-situ Fourier transformed infrared spectroscopy and density functional theory calculations revealed the photocatalytic H_(2)O_(2) production mechanism.The generated H_(2)O_(2) demonstrated enhanced antibacterial activity.This work presents the first application of Nb_(2)C in the photocatalytic synthesis of H_(2)O_(2) and provides a novel strategy for constructing COF-based heterojunctions for photocatalytic H_(2)O_(2) generation and wastewater treatment.
基金support from the Shandong Provincial Natural Science Foundation(ZR2021MB047)the National Natural Science Foundation of China(22276069)。
文摘Controlling the intermolecular charge transfer between co-reactants and emitters represents a promising strategy for elucidating the luminescent mechanism and enhancing the efficiency of electrochemiluminescence(ECL)systems.Herein,a self-enhanced ECL microreactor was prepared by bimetallic Zn-/Co-porphyrin covalent organic framework(COF_(Zn/CoP-Ph)@MWCNTs),in which co-reaction accelerators(cobalt porphyrin)and luminophores(zinc porphyrin)were precisely woven into the COFs skeleton via covalent bonds.Owing to the unique topological structure,the rational arrangement of coreaction accelerators and luminophores in a spatially confined environment effectively controlled the intermolecular charge transfer.And the spatially restricted environment formed by the COF_(Zn/CoP-Ph)@MWCNTs microreactor avoided the problem of disordered diffusion of active intermediates,leading to an enhanced ECL response.Thanks to the synergistic impacts of the factors above,the ECL intensity of the bimetallic COF_(Zn/CoP-Ph)@MWCNTs was 10.2-folds stronger than the zinc porphyrin monomer.Therefore,the self-enhanced ECL sensor was constructed for miRNA-155 detection via an“on-off”ECL quenching mechanism and a cycling amplification strategy,displayed a broad linear range(0.10 pM–10μM)and a low limit of detection(0.51 fM).In brief,studying the programmable structures and tunable electronic paths of high-performance COF materials would provide good access for the engineering self-enhanced ECL system and the construction of ultrasensitive sensors.
基金financially supported by the Natural Science Foundation of Shandong Province(No.ZR2022MB034)。
文摘The advancement of functional adhesives featuring recyclable and repairable properties is of great significance in interfacial science and engineering.Herein,a series of high-strength,recyclable fluorine-containing adhesives(ESOx-FPF)were designed and synthesized by crosslinking two prepolymers,FPF-B(derived from side-chain fluorinated diol,isocyanate,and aminoboric acid)and ESO-B(synthesized from biobased epoxy soybean oil and aminoboric acid),through dynamic boro-oxygen bonds.The resulting adhesive exhibited an optimal tensile strength of 42 MPa and the shear strength on steel plates reached as high as 3.89 MPa.More importantly,benefiting from the dynamic reversibility of the boron-oxygen bonds along with the hydrogen bonds interaction,ESOx-FPF can be welded with the assistance of solvents and recycled for multiple cycles.The outstanding healing efficiency and excellent reprocessability of these functional adhesives were confirmed by mechanical testing.Moreover,the as-prepared adhesives demonstrated universal and remarkable adhesion to various substrates,such as aromatic polyamide,aluminum plates and polycarbonate,meanwhile,they could be easily disassembled and recycled using ethanol without damaging the substrates surface.This study not only provides a simple strategy for the synthesis of eco-friendly adhesives with weldable and recyclable properties,but also sheds light on the development of other functional materials utilizing dynamic covalent chemistry.
