Hydrogen-bonded organic framework modified separator for simultaneously enhancing the safety and electrochemical performance of Ni-rich lithium-ion battery

Nickel-rich layered oxide cathode(LiNi_(x)Co_(y)Mn_(1−x−y)O_(2),x>0.5,NCM)shows substantial potential for applications in longer-range electrical vehicles.However,the rapid capacity decay and serious safety concerns impede its practical viability.This work provides a hydrogen-bonded organic framework(HOF)modification strategy to simultaneously improve the electrochemical performance,thermal stability and incombustibility of separator.Melamine cyanurate(MCA),as a low-cost and reliable flame-retardant HOF,was implemented in the separator modification layer,which can prevent the battery short circuit even at a high temperature.In addition,the supermolecule properties of MCA provide unique physical and chemical microenvironment for regulating ion-transport behavior in electrolyte.The MCA coating layer enabled the nickel-rich layered oxide cathode with a high-capacity retention of 90.3%after 300 cycles at 1.0 C.Collectively,the usage of MCA in lithium-ion batteries(LIBs)affords a simple,low-cost and efficient strategy to improve the security and service life of nickel-rich layered cathodes.

High-throughput mechanistic study of highly selective hydrogen-bonded organic frameworks for electrochemical nitrate reduction to ammonia

Hydrogen-bonded organic frameworks(HOFs),an emerging porous macrocyclic materials linked by hydrogen-bond,hold potential for gas separation and storage,sensors,optical,and electrocatalysts.Here,HOF-based electrocatalysts are rationally developed for nitrates reduction to ammonia,allowing not only to regulate wastewater pollution but also to accomplish carbon-neutral ammonia(NH_(3))synthesis.We preform high-throughput computational screening of thirty-six HOFs with various metals as active sites,denoted as HOF-M1,for nitrate reduction reaction(NO_(3)RR)toward NH_(3).We have implemented a hierarchical four-step screening strategy,and ultimately,HOF-Ti1 was selected based on its exceptional catalytic activity and selectivity in the NO_(3)RR process.Through additional analysis,we discovered that the d band center of the active metal sites serves as an effective parameter for designing and predicting the performance of HOFs in NO_(3)RR.This research not only showcases the immense potential of electrocatalysis in transforming NO_(3)RR into NH_(3)but also provides researchers with a compelling incentive to undertake further experimental investigations.

Two New Inclusion 1,4-Butylenediphosphonates with 3D Hydrogen-bonded Frameworks

Two new inclusion 1,4-butylenediphosphonates with three-dimensional hydrogen- bonded frameworks have been synthesized and determined by single-crystal X-ray diffraction. In compound 1, the two-dimensional cationic substructures interpenetrate into the anionic framework, and in compound 2, the cations are encapsulated in the three-dimensional framework. Crystal 1 (C14H24N2O8P2) belongs to triclinic, space group P?with a = 9.4645(2), b = 9.6490(2), c = 11.9479(3) ? = 79.7420(10), b = 73.5650(10), = 63.8420(10), V = 937.55(4) 3, Z = 2, Mr = 410.29, Dc = 1.453 g/cm3, m(MoKa) = 0.276 mm-1, F(000) = 432, the final R = 0.0465 and wR = 0.1304 for 3274 independent reflections. Crystal 2 (C18H26N2O10P2) is of monoclinic, space group P21/c with a = 9.7069(12), b = 16.227(2), c = 6.9339(9) ? b = 98.834(3), V = 1079.2(2) ?, Z = 2, Mr = 492.35, Dc = 1.515 g/cm3, m(MoKa) = 0.261 mm-1, F(000) = 516, the final R = 0.0611 and wR = 0.1162 for 1871 independent reflections.

Synthesis and Crystal Structure of a New Charge-assisted Hydrogen-bonded Host Framework [Co(en)_3]_2[Zr_2(C_2O_4)_7]·2H_2O

Using the deep eutectic solvent formed of oxalic acid and choline chloride, a new charge-assisted hydrogen-bonded host framework [Co（en）312[Zr2（C2O4）7]·2H2O （1） has been obtained. The title complex crystallizes in the monoclinic, space group P21/n （No. 14） with a = 7.7448（10）, b = 14.5683（19）, c = 19.375（3） A, fl = 92.124（2）°, V= 2184.5（5） A3, Z = 4, Dc = 1.996 gcm-3, F（000） = 1332, μ = 1.328 mm＂1, R = 0.0353 and wR = 0.0718 （1 〉 2α（I））. Single-crystal structure analysis reveals that the title complex possesses a 3D network assembled through a multitude of charge-assisted hydrogen bonds between the in situ generated anionic coordination complexes [Zr2（C204）7]6- and metal complexes Co（en）33＋.

Halogen-bond induced unusual polyhalogen anions formation in hydrogen-bonded frameworks to secure iodine sequestration

Safe confinement of fission iodine isotopes for long-term radioactive waste disposal remains a formidable challenge,as conventional sorbents provide inherently weak iodine-host interactions.We report here a novel halogen bond(X-bond)directed strategy to sequester volatile iodine in hydrogen-bonded(H-bonded)frameworks with unprecedented stability.Charge-assisted Hbonded frameworks bearing open halide sites are developed,showing distinctive iodine encapsulation behaviors without compromising the crystallinity.Direct crystallographic evidence indicates the formation of X-bonds,i.e.,I–I···Cl^(−) and I–I···Br^(−),within the confined pore channels.Unusual polyhalogen anions,i.e.,[I_(2)Cl_(2)]^(2−)and[I_(2)Br_(2)]^(2−),sustained in H-bonded frameworks are identified for the first time.The X-bond reinforced host-guest interaction affords robust iodine trapping without leaking out even at elevated temperatures up to 180℃.By integrating the halogen-bond chemistry with H-bonded frameworks,this study offers fresh concepts for developing effective host reservoirs to secure fission iodine isotopes from spent fuel reprocessing off-gases.

Stable hydrogen-bonded organic frameworks and their photo-and electro-responses

Hydrogen-bonded organic frameworks(HOFs)are a recent class of porous materials that have garnered considerable research interest owing to their distinctive characteristics.HOFs can be constructed through judicious selection of H-bonding motifs,which are further enforced by other weak intermolecular interactions such asπ–πstacking,van der Waals forces,and framework interpenetration.Taking advantage of these interactions,we can expand the functional field of HOFs by introducing active molecules.Recently,researchers have made substantial advancements in using HOFs for chemical sensing,catalysis,proton conduction,biological applications,and others.The low bonding energy of H-bonds allows for precise control over the concentration of ligands in solvents,forming diverse HOF structures.These varied structures offer significant advantages for producing HOFs with photo-responsive and electro-responsive properties.However,the presence of H-bonds in HOFs results in their inherent lower stability compared to metal-organic frameworks(MOFs)and covalent-organic frameworks(COFs)formed via coordination and covalent bonds,respectively.As a result,the pursuit of stable and innovative HOF materials with novel functional sites remains an ongoing challenge.This review provides an overview of recent research progress in the development of new strategies for stable HOF synthesis and applications of HOFs with stimuli-responsive properties.We first classified all synthetic methods reported to date and discussed the stable HOFs synthesized,as well as their unique properties and applications.In addition,we summarized the applications of HOFs utilizing their synergistic responses to external stimuli,including photo,electrical,pressure,and chemical stimuli.We systematically reviewed stable HOF synthesis and applications,which may lead to a deeper understanding of the structure–activity relationship for these materials and guide future HOF design.

A hydrogen-bonded organic framework containing fluorescent carbazole and responsive pyridyl units for sensing organic acids

Hydrogen-bonded organic frameworks(HOFs)are a promising candidate for optical sensing,but the lack of effective design strategies poses significant challenges to the construction of HOFs for organic acid sensing.In this work,the first HOF for organic acid sensing is reported by constructing a multiplepyridine carbazole-based dense HOF,namely HOF-FJU-206,from a tripyridine-carbazole molecular 3,6-bis(pyridin-4-yl)-9-(4-(pyridin-4-yl)phenyl)-9H-carbazole(CPPY)with carbazole center for luminescence,pyridyl sites for its responsive of hydrogen proton,and narrow channels in the dense framework for the diffusion of hydrogen protons.HOF-FJU-206 exhibits differential responsively fluorescence sensing and recovery properties to formic,acetic,and propionic acids with different molecular sizes and p Kavalue(acid dissociation constant).The dissociation degree of various acids can be determined by analyzing the slope of changes in both peak wavelength and intensity of in-situ fluorescence,which easily enables the dual-corrective recognition of different acids.The varying degree of protonation at pyridine sites is proved to be the reason for differential sensing of various acids,as demonstrated by1H NMR spectra,X-ray photoelectron spectroscopy(XPS)characterization,and modeling studies.

Sticked-Layer Strategy to a Flexible-Robust Hydrogen-Bonded Organic Framework for Efficient C_(2)H_(2)/CO_(2)Separation

Flexible-robust hydrogen-bonded organic frameworks(HOFs)are attracting increasing interest due to their excellent separation performance for important industrial gases,but the construction remains challenging.Herein,a sticked-layer strategy is first proposed to construct a flexible-robust HOF,HOFFJU-8,from a donor(D)–π–acceptor(A)molecule 4,4′,4″,4‴-(pyrrolo[3,2-b]pyrrole-1,2,4,5-tetrayl)tetrabenzonitrile(DP-4CN).HOF-FJU-8 is amicroporous three-dimensional framework composed of two kinds of DP-4CN molecules,one acting as building units for the two-dimensional layer via C≡N···H–C hydrogen bond dimers and another as the sticks to link the layers along channels through D–Aπ···πinteractions.The activated framework HOF-FJU-8a possesses flexible-robust pore characteristics,as determined by the gas adsorption and in situ gas-loaded powder X-ray diffraction.HOF-FJU-8a exhibits adaptive adsorption and stronger binding affinity to C_(2)H_(2)rather than CO_(2)due to the flexible-robust nature,which can effectively separate acetylene and carbon dioxide mixtures.

Integrating Levels of Hierarchical Organization in Porous Organic Molecular Materials

Porous organic molecular materials(POMMs)are an emergent class of molecular-based materials characterized by the formation of extended porous frameworks,mainly held by non-covalent interactions.POMMs represent a variety of chemical families,such as hydrogen-bonded organic frameworks,porous organic salts,porous organic cages,C-H···πmicroporous crystals,supramolecular organic frameworks,π-organic frameworks,halogen-bonded organic framework,and intrinsically porous molecular materials.In some porous materials such as zeolites and metal organic frameworks,the integration of multiscale has been adopted to build materials with multifunctionality and optimized properties.Therefore,considering the significant role of hierarchy in porous materials and the growing importance of POMMs in the realm of synthetic porous materials,we consider it appropriate to dedicate for the first time a critical review covering both topics.Herein,we will provide a summary of literature examples showcasing hierarchical POMMs,with a focus on their main synthetic approaches,applications,and the advantages brought forth by introducing hierarchy.

Two-in-one tecton strategy to construct single crystalline hydrogen-bonded organic framework with high proton conductivity above 100℃

By tactically integrating two different kinds of proton donors and acceptors into one supramolecular tecton, a new crystalline hydrogen-bonded organic framework(HOF-SXU-1) has been developed. HOF-SXU-1 features a remarkable proton conductivity as high as 6.32 mS cm^(-1) and an extremely low activation energy of 0.16 eV at 160℃ under anhydrous N_(2) conditions.By contrast, under identical conditions, the organic precursors of HOF-SXU-1 only exhibit negligible proton conduction performance, demonstrating that the formation of HOF is crucial for excellent proton conduction performance.

等离激元@MIL系列铁基金属有机骨架表面增强拉曼光谱复合基底的制备与应用进展

表面增强拉曼光谱(surface-enhanced Raman spectroscopy,SERS)是一种高灵敏度、高特异性的新型指纹光谱分析方法,在众多领域应用潜力巨大。SERS效应的产生依赖于高性能的SERS活性基底。常规等离激元纳米粒子(plasmonic nanostructures/nanoparticles,NPs)作为传统SERS基底存在富集效果不佳、抗干扰能力差等问题,在一定程度上限制了SERS技术在实际样品检测中的应用。铁基金属有机骨架(iron-based organometallic frameworks,Fe-MOFs)因其具有多孔隙、高稳定性的结构特点,可以为NPs提供具有富集效果和筛选效应的稳定检测平台,实现特定成分检测和检测后产物的无害化处理。本文重点总结了MIL系列NPs@Fe-MOFs复合SERS基底的制备方法,介绍了MIL系列Fe-MOFs在SERS中应用的最新进展,讨论了目前MIL系列NPs@Fe-MOFs复合SERS基底亟待解决的问题,并对未来的应用领域和发展前景进行了展望,旨在为新型SERS基底的构建和应用提供更多依据。

Elastic hydrogen-bonded ionic framework

Elasticity,as an emerging phenomenon of crystals,endows the newfangled properties on crystals owing to the altered local crystallinity in the deformed state,and hence attracts increasing research endeavors.However,only a few molecular crystals and a limited number of one-dimensional coordination polymer crystals have exhibited such fantastic elastic response under mechanical stress.Herein,we report the first example of elastic hydrogen-bonded ionic framework(HIF)of{(CN_(3)H_(6))_(2)[Ti(μ_(2)-O)(SO_(4))_(2)]}n,assembled from one-dimensional negatively charged inorganic[Ti(μ_(2)-O)(SO_(4))_(2)]n 2n-chains and positively charged organic guanidinium cations via hydrogen bonds and electrostatic interactions.The slender prismatic single crystal exhibits remarkable elasticity with an optimal elastic bending strain(ε)of 2.5%.Impressively,the crystals give rise to two-dimensional elasticity owing to the equivalent crystallographic planes of the exposed faces and an unusual elastic response at liquid nitrogen temperature.The in-depth crystallographic analyses reveal hydrogen bonds and electrostatic interactions between anion chains and cations function like adhesive glue and account for such specific elastic properties,owing to the flexible and dynamic attributes of hydrogen bonds as they can work in a range of distance and orientation.And the channel in HIF provides space for bending with reduced strain.Incorporating these factors into low-dimensional crystals could be a general guidance for designing elastic crystals.Elasticity ganged with other intrinsic properties of HIF materials could inspire their newfangled applications in the near future.

Information encryption with a high information-carrying capacity based on a stimulus-responsive hydrogen-bonded organic framework and a smartphone

Information-carrying capacity has become an important factor in the development of encryption and anti-counterfeiting.Herein,a hydrogen-bonded organic framework(HOF-PyTTA)was developed as novel anti-counterfeiting ink without rare metals and a smartphone-based APP was written for encryption and anti-counterfeiting.We found that the fluorescence of HOF-PyTTA can be quenched by Fe^(3+)ions and recovered by the addition of ascorbic acid.And the fluorescence of HOF-PyTTA can be enhanced by the increasing concentrations of ethanol.Based on these stimulus-response properties,four anti-counterfeiting models with gradually increased security were studied.Mode one was printed by HOFs ink and decrypted by UV light.Mode two was based on HOF-PyTTA and CsPbBr_(3)inks(or HOF-PyTTA-Fe^(3+))which are used to separately print the genuine and pirated information.A decryption reagent was applied to get the genuine information.Furthermore,we successfully construct a dynamic information encryption anti-counterfeiting model using a fluorescence array in combination with an information encryption anticounterfeiting APP.The circular array is printed by several concentrations of HOF-PyTTA ink and different RGB thresholds are set with the help of the information encryption anti-counterfeiting APP,to obtain distinct encrypted anti-counterfeiting information,thus accomplishing a high information-carrying capacity.

Hydrogen-bonded organic framework for red light-mediated photocatalysis

The development of heterogeneous molecule-based catalysts for red light-mediated photocatalysis is still challenging due to the improper light absorption for most materials and the photoactivity deactivation for solid assembly.Herein,red light photocatalysis with a hydrogen-bonded organic framework(HOF)is established.This HOF,named HOF-66,is formed from the self-assembly of guanine-decorated naphthalenediimide(NDI)molecule through hydrogen-bonded guanine-quadruplex nodes,showing square grid supramolecular layers confirmed by powder X-ray diffraction analysis.In contrast to unsubstituted NDI HOF,introduction of ethylamino groups to NDI core in HOF-66 tunes strong electronic maximum absorption peak to 619 nm,allowing red light photocatalysis of singlet oxygen evolution proved by 1,3-diphenylisobenzofuran degradation and electron spin resonance determination.Particularly,under the same conditions,the sulfide oxidation rate in the presence of HOF-66 was 28 times higher compared to its unsubstituted analogue.This work integrates the molecular design and aggregation effect towards the application of HOFs,opening a new gate for red light photocatalysts.

Topochemical polymerization of hydrogen-bonded organic framework for supporting ultrafine palladium nanoparticles

Topochemical polymerization of molecular crystals into porous materials is of significance due to their promising applications in the field of adsorption and catalysis,yet rarely reported due to the synthesis difficulty.Herein,a hydrogen-bonded organic framework(HOF-45)has been fabricated by the crystallization of a cage-like building block containing three alkynyl groups.It exhibits almost mesoporous structure demonstrated by single crystal X-ray diffraction study.Light-driven topochemical polymerization of HOF-45 with ethanedithiol covalently links alkynyl groups in HOF-45,generating a hydrogen-bond and covalentbond cross-linked material(HOF-45C).In contrast to HOF-45,cross-linked HOF-45C retains the crystalline nature and displays improved solution resistence according to the powder X-ray diffraction data.In particular,HOF-45C is able to support the growth of ultrafine palladium nanoparticles with the average size of ca.1.9 nm for rapidly promoting the degradation of nitrophenol,methyl orange,and congo red with the help of NaBH_(4)as well as Suzuki-Miyaura coupling reaction.This work inputs a new idea on the HOFs application in preparing covalent-linked porous organic materials.

Superprotonic Conductivity of Guanidinium Organosulfonate Hydrogen-Bonded Organic Frameworks with Nanotube-Shaped Proton Transport Channels

Grasping proton transport pathways and mecha-nisms is vital for the application of fuel cell technology.Herein,we screened four guanidinium organosulfonate charge-assisted hydro-gen-bonded organic frameworks(HOFs),namely,GBBS,G3TSPHB,G4TSP,and G6HSPB,which possess high hydrogen-bonded density proton transport networks shaped like nanotubes.These materials were prepared by self-assembly through charge-assisted interactions between guanidinium cations and organo-sulfonate anions,as well as by host-guest regulation.At 80℃ and 93%RH,the proton conductivity of GBBS,G3TSPHB,G4TSP,and G6HSPB can reach 4.56×10^(-2),2.55×10^(-2),4.01×10^(-2),and 10^(-1) cm^(-1),Doping G6HSPB into the Nafion matrix prepared composite membranes for testing the performance of fuel cells.At 80°C and 98%RH,the proton conductivity of 9%-G6HSPB@Nafion reached a maximum value of 1.14×10^(-1) S cm^(-1),which is 2.8 times higher than recast Nafion.The results showed that charge-assisted HOFs with high proton channel density have better proton transport properties,providing a reference for the design of highly proton-conducting materials.

Robust Hydrogen-Bonded Organic Framework with Four-Fold Interpenetration for Adsorptive Separation of C_(2)H_(6)/C_(2)H_(4) and Xe/Kr

Hydrogen-bonded organic frameworks(HOFs)are an emerging class of porous materials that hold promise for the adsorptive separation of industrially relevant gas mixtures.However,developing HOFs with high thermal stability and resistance to water remains a daunting challenge.We report here a microporous HOF(HIAM-103)assembled from a hexacarboxylate linker(2,4,6-trimethylbenzene-1,3,5-triylisophthalic acid,H6TMBTI).The compound crystallizes in the trigonal crystal system,and its structure is a four-fold interpenetrated network.Upon thermal activation,the single crystals remain intact,allowing for precise determination of the activated structure.HIAM-103 exhibits remarkable thermal and hydrothermal stability.Its microporous channels demonstrate selective adsorption of C_(2)H_(6)over C_(2)H_(4)and Xe over Kr,and its separation capability toward mixed gases has been validated by column breakthrough experiments under dry and humid conditions.The preferential gas adsorption sites and separation mechanisms have been uncovered through DFT analysis,which suggests that the methyl group decorated 1D channels are the primary reason for the selective adsorption.

一种有效吸附Pb(Ⅱ)的Zr基金属有机凝胶的合成

以合成的4,4,4-三甲酸三苯胺(H3TCA)为主配体,通过溶剂热法合成了一种超分子无定型的锆基金属有机凝胶(Zr-MOG)。并通过一种简单的恒定时间控制晶化方法,使UIO-66(即Zr-MOF)凝胶化合成非晶态的Zr-MOG。结果表明,所制备的Zr-MOG拥有凝胶软材料的多层结构和非晶聚合物网络,对Pb(Ⅱ)具有良好的吸附能力。此外,以冰醋酸为晶化促进剂,成功地实现了晶态MOF和高分散非晶态MOG的转化。

Engineering HOF‑Based Mixed‑Matrix Membranes for Efficient CO_(2) Separation

Hydrogen-bonded organic frameworks(HOFs)have emerged as a new class of crystalline porous materials,and their application in membrane technology needs to be explored.Herein,for the first time,we demonstrated the utilization of HOF-based mixed-matrix membrane for CO_(2) separation.HOF-21,a unique metallo-hydrogen-bonded organic framework material,was designed and processed into nanofillers via amine modulator,uniformly dispersing with Pebax polymer.Featured with the mix-bonded framework,HOF-21 possessed moderate pore size of 0.35 nm and displayed excellent stability under humid feed gas.The chemical functions of multiple binding sites and continuous hydrogen-bonded network jointly facilitated the mass transport of CO_(2).The resulting HOF-21 mixed-matrix membrane exhibited a permeability above 750 Barrer,a selectivity of~40 for CO_(2)/CH_(4) and~60 for CO_(2)/N_(2),surpassing the 2008 Robeson upper bound.This work enlarges the family of mixed-matrix membranes and lays the foundation for HOF membrane development.

钒掺杂Cd-金属有机框架衍生碳基材料对染料光降解的研究

通过水热法合成了四种锌、镉过渡金属有机框架,分别将四种金属有机框架按质量比2∶1掺入偏钒酸铵,在200 mL/min的氮气氛围下以400℃、500℃、600℃煅烧得到新型金属有机框架衍生碳基材料.利用XRD、SEM、XPS等测试方法对所制备的材料进行了表征,并研究了其对有机染料亚甲基蓝、罗丹明B、刚果红、结晶紫、甲基橙的光催化降解效果.实验结果表明:经紫外光照240 min后,经500℃煅烧后所得的钒掺杂Cd-金属有机框架衍生碳基材料对有机染料具有优异的光催化降解效果,其中,对结晶紫溶液的光催化降解率可达到99.27%.