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Herein, we investigated hydrogels composed of boronic-acid-functionalized alginate and blended with polyvinyl alcohol (PVA) of different molecular weights to control the release of metoclopramide hydrochloride as a function of pH and shear stress. The functionalization of alginate introduced dynamic covalent bonding and pH-responsive properties that can modulate network connectivity. The study investigated the viscoelastic properties of the hydrogels, their drug release profiles, and their responsiveness to changes in pH and shear forces. The results showed that a higher PVA molecular weight and alkaline pH conditions increased hydrogel viscosity and stiffness due to a more stable and interconnected network structure than acidic pH. Metoclopramide release revealed that the hydrogels exhibited pH-responsive drug release behavior. The drug was more readily released under acidic conditions due to the instability of sp2-hybridized boronate ester bonds. The influence of shear forces on the release of metoclopramide was also investigated at shear rates of 1, 10, and 100 s−1, revealing their effect on matrix stiffening. Research shows that AlgBA/PVA hydrogels have unique properties, such as dynamic covalent bonding, that make them sensitive to external mechanical forces. This sensitivity makes them ideal for applications where physiological conditions trigger drug release. [ABSTRACT FROM AUTHOR]

Rotaxanes are typically prepared using covalent bonds to trap a wheel component onto an axle molecule, and rotaxane-type wheel–axle assembly using only noncovalent interactions has been far less explored. Here we show that a dinickel(II) metallomacrocycle forms two different types of wheel–axle assemblies with a dibenzylammonium axle molecule based only on noncovalent interactions. The non-threaded assembly was obtained by introduction of Ni2+ into the macrocycle before the complexation with the axle molecule (metal-first method). The non-threaded assembly was in rapid equilibrium with each of the components in solution. The threaded assembly was obtained by introduction of Ni2+ after the formation of a pseudorotaxane from the non-metalated wheel and the axle molecule (axle-first method). The threaded assembly was not in equilibrium with the dissociated species even though it was maintained only by noncovalent interactions. Thus, formation of one of the non-threaded and threaded wheel–axle assemblies over the other is governed by the assembly pathway. Mechanically interlocked rotaxanes are typically prepared using covalent bonds to trap a wheel component onto an axle molecule, and rotaxane-type wheel–axle assembly using only noncovalent interactions has been far less explored. Here, a dinickel(II) metallomacrocycle is found to form two different types of wheel–axle assemblies, with a dibenzylammonium axle molecule forming both non-threaded and rotaxane-type threaded assemblies, based only on noncovalent interactions, with formation of one over the other governed by the assembly pathway. [ABSTRACT FROM AUTHOR]

Artificial interfaces provide a comprehensive approach to controlling zinc dendrite and surface corrosion in zinc‐based aqueous batteries (ZABs). However, due to consistent volume changes during zinc plating/stripping, traditional interfacial layers cannot consistently adapt to the dendrite surface, resulting in uncontrolled dendrite growth and hydrogen evolution. Herein, dynamic covalent bonds exhibit the Janus effect towards zinc deposition at different current densities, presenting a holistic strategy for stabilizing zinc anode. The PBSC intelligent artificial interface consisting of dynamic B−O covalent bonds is developed on zinc anode to mitigate hydrogen evolution and restrict dendrite expansion. Owing to the reversible dynamic bonds, PBSC exhibits shape self‐adaptive characteristics at low current rates, which rearranges the network to accommodate volume changes during zinc plating/stripping, resisting hydrogen evolution. Moreover, the rapid association of B−O dynamic bonds enhances mechanical strength at dendrite tips, presenting a shear‐thickening effect and suppressing further dendrite growth at high current rates. Therefore, the assembled symmetrical battery with PBSC maintains a stable cycle of 4500 hours without significant performance degradation and the PBSC@Zn||V2O5 pouch cell demonstrates a specific capacity exceeding 170 mAh g−1. Overall, the intelligent interface with dynamic covalent bonds provides innovative approaches for zinc anode interfacial engineering and enhances cycling performance. [ABSTRACT FROM AUTHOR]

Biochemical systems make use of out‐of‐equilibrium polymers generated under kinetic control. Inspired by these systems, many abiotic supramolecular polymers driven by chemical fuel reactions have been reported. Conversely, polymers based on transient covalent bonds have received little attention, even though they have the potential to complement supramolecular systems by generating transient structures based on stronger bonds and by offering a straightforward tuning of reaction kinetics. In this study, we show that simple aqueous dicarboxylic acids give poly(anhydrides) when treated with the carbodiimide EDC. Transient covalent polymers with molecular weights exceeding 15,000 are generated which then decompose over the course of hours to weeks. Disassembly kinetics can be controlled using simple substituent effects in the monomer design. The impact of solvent polarity, carbodiimide concentration, temperature, pyridine concentration, and monomer concentration on polymer properties and lifetimes has been investigated. The results reveal substantial control over polymer assembly and disassembly kinetics, highlighting the potential for fine‐tuned kinetic control in nonequilibrium polymerization systems. [ABSTRACT FROM AUTHOR]

Self‐assembly of chromophoric systems is a prerequisite to create well‐ordered, processable nanomaterials with multiple functionalities. In the past two decades, the field of functional organic materials has primarily focused on systems featuring only one type of dye/π‐conjugated unit. Consequently, many reports with mechanistic insights on the self‐assembly of the dyes featuring different molecular packing have been reported. Subsequently, we have witnessed several attempts to organize the multi‐chromophoric systems in solution and solid‐state via different approaches using self‐assembly as a tool. Incorporation of more than one dye is important in creating materials with tuneable optoelectronic properties. Consequently, self‐assembly of more than one chromophoric systems have been investigated to some extent. This review aims to discuss the self‐assembled materials derived from discrete π‐conjugated systems comprising more than one dye units connected through covalent bonding (multi‐chromophoric systems). Molecular design of various multi‐chromophoric systems leading to the formation of crystals, liquid crystals and supramolecular polymers have been correlated with corresponding properties. We envisage that classification of self‐assembled multi‐chromophoric systems, with a note on tuneable optoelectronic properties, can provide a deeper understanding on the molecular design strategies, which is important in the fabrication of functional organic materials with optimum performances. [ABSTRACT FROM AUTHOR]

Due to their remarkable features of lightweight, high strength, stiffness, high‐temperature resistance, and corrosion resistance, carbon fiber reinforced polymers (CFRPs) are extensively used in sports equipment, vehicles, aircraft, windmill blades, and other sectors. The urging need to develop a resource‐saving and environmentally responsible society requires the recycling of CFRPs. Traditional CFRPs, on the other hand, are difficult to recycle due to the permanent covalent crosslinking of polymer matrices. The combination of covalent adaptable networks (CANs) with carbon fibers (CFs) marks a new development path for closed‐loop recyclable CFRPs and polymer resins. In this review, we summarize the most recent developments of closed‐loop recyclable CFRPs from the unique paradigm of dynamic crosslinking polymers, CANs. These sophisticated materials with diverse functions, oriented towards CFs recycling and resin sustainability, are further categorized into several active domains of dynamic covalent bonds, including ester bonds, imine bonds, disulfide bonds, boronic ester bonds, and acetal linkages, etc. Finally, the possible strategies for the future design of recyclable CFPRs by combining dynamic covalent chemistry innovation with materials interface science are proposed. [ABSTRACT FROM AUTHOR]

Microenvironment regulation of M‐N4 single‐atom catalysts (SACs) is a promising way to tune their catalytic properties toward the electrochemical CO2 reduction reaction. However, strategies that can effectively introduce functional groups around the M‐N4 sites through strong covalent bonding and under mild reaction conditions are highly desired. Taking the hydrophilic Ni‐N4 SAC as a representative, we report herein a [2+1] cycloaddition reaction between Ni‐N4 and in situ generated difluorocarbene (F2C:), and enable the surface fluorocarbonation of Ni‐N4, resulting in the formation of a super‐hydrophobic Ni‐N4‐CF2 catalyst. Meanwhile, the mild reaction conditions allow Ni‐N4‐CF2 to inherit both the electronic and structural configuration of the Ni‐N4 sites from Ni‐N4. Enhanced electrochemical CO2‐to‐CO Faradaic efficiency above 98 % is achieved in a wide operating potential window from −0.7 V to −1.3 V over Ni‐N4‐CF2. In situ spectroelectrochemical studies reveal that a highly hydrophobic microenvironment formed by the −CF2− group repels asymmetric H‐bonded water at the electrified interface, inhibiting the hydrogen evolution reaction and promoting CO production. This work highlights the advantages of [2+1] cycloaddition reactions on the covalent modification of N‐doped carbon‐supported catalysts. [ABSTRACT FROM AUTHOR]

Boric acid, H3BO3, is a molecular solid made up of layers held together by weak van der Waals forces. It can be considered a pseudo "2D" material, like graphite, compared to graphene. The key distinction is that within each individual layer, the molecular units are connected not only by strong covalent bonds but also by hydrogen bonds. Therefore, classic liquid exfoliation is not suitable for this material, and a specific method needs to be developed. Preliminary results of exfoliation of boric acid particles by combination of ultrasound and the use of surfactants are presented. Ultrasound provides the system with the energy needed for the process, and the surfactant can act to keep the crystalline flakes apart. A system consisting of a saturated solution and large excess solid residue of boric acid was treated in this way for a few hours at 40 °C in the presence of various sodium stearate, proving to be very promising, and an incipient exfoliation was achieved. [ABSTRACT FROM AUTHOR]

Dynamic bonds can facilitate reversible formation and dissociation of connections in response to external stimuli, endowing materials with shape memory and self-healing capabilities. Temperature is an external stimulus that can be easily controlled through heat. Dynamic covalent bonds in response to temperature can reversibly connect, exchange, and convert chains in the polymer. In this review, we introduce dynamic covalent bonds that operate without catalysts in various temperature ranges. The basic bonding mechanism and the kinetics are examined to understand dynamic covalent chemistry reversibly performed by equilibrium control. Furthermore, a recent synthesis method that implements dynamic covalent coupling based on various polymers is introduced. Dynamic covalent bonds that operate depending on temperature can be applied and expand the use of polymers, providing predictions for the development of future smart materials. [ABSTRACT FROM AUTHOR]

Acylhydrazone bonds can participate in dynamic exchange reactions under acid-stimulated conditions, and disulfide bonds can participate in dynamic exchange reactions under thermally stimulated conditions. It is of great significance to prepare epoxy vitrimer that can rapidly self-repair under acid and thermal stimulation conditions. In this paper, vanillin was used as raw material, and monomer (VAN-AD) containing acylhydrazone bond was synthesized by reaction with adipic dihydrazide. Then, VAN-AD and 4-aminophenyl disulfide (SS) were cured together with glycerol triglycidyl ether to prepare an epoxy vitrimer with acylhydrazone and disulfide dual dynamic covalent bonds. Where VAN-AD provides some of the flexible chain segments and acylhydrazone bonds and SS provides the aromatic phenyl and disulfide bonds. The material was prepared in a simple process and under mild condition, and the properties of the material were optimized by changing the ratio of VAN-AD to SS. The Tg of the material was 50 °C when the ratio of SS was the highest, the thermal stability was enhanced with the increase of the ratio of SS, and the maximum tensile strength up to 50.9 MPa, and the material can be completely degraded by DMF with 5% HCl. It is worth noting that the material shows rapid self-healing properties under acid-heat conditions, self-healing rates up to 97.37%, and the tensile strength can reach 26 MPa after repair. The material can be successfully remodeled by hot pressing for 1 h at 140 °C and 10 MPa. [ABSTRACT FROM AUTHOR]

CeO2 has high elastic modulus and thermal stability, as well as good surface effects, making it ideal as a reinforcement for aluminum matrix composites. In this paper, the interfacial relationships between Al and CeO2 was studied by first-principles calculation, and the nucleation mechanism of aluminum matrix growth on CeO2 substrate was discussed. First, the Al/CeO2 interface matching crystal surface was identified as the Al(111)/CeO2(111) interface. Then, the surface work function was calculated for all surfaces constituting the Al(111)/CeO2(111) interface, and the results showed that the Al(111) loses charge more easily than CeO2(111). Subsequently, the interface energy and work of adhesion of the Al(111)/CeO2(111) interface were calculated, and the results showed that the interface energy of O1–Al was the smallest (0.07 J/m2), the work of adhesion of O2 interface energy of O1–Al was the smallest (0.07 J/m2), the work of adhesion of O2–Al was the largest (9.36 J/m2)Al was the largest (9.36 J/m2). Finally, the combined properties of the Al(111)/CeO2(111) interface were analyzed by the electronic properties at the interface, and the results showed that The Al(111)/CeO2(111) interface is a mixture of ionic and covalent bonds. Therefore, the calculated results confirm that the effectiveness of CeO2 as a heterogeneous nucleation substrate for Al. This study provides a theoretical basis for the nucleation mechanism of the heterogeneous nucleation interface between CeO2 and aluminum matrix. [ABSTRACT FROM AUTHOR]

Recyclability of polyurethane materials is significant to relieve environmental problems caused by damaged polymers. Inspired by plenty of self‐healing properties based on dynamic covalent bonds. A high mechanical strength and thermally reversible polyurethane adhesive are acquired through co‐polymerization of poly‐1,4‐butylene adipate glycol (PBA), soybean oil‐based polyol (MESO), and toluene diisocyanate (TDI) whose linear polymer chains are constructed by Diels–Alder reaction between furfuryl alcohol (FA) and bismaleimide (BMI), named DAPU. Further, the obtained polyurethane adhesives show great recyclability, mechanical performance (Whose tensile strength can reach 91.7 MPa), and appropriate self‐healing ability through the thermally reversible Diels–Alder covalent bonds and hydrogen bonds between urethane groups, which may pave a way for further development of recyclable materials. [ABSTRACT FROM AUTHOR]

The electrostatic attraction between charges of opposite signs and the repulsion between charges of the same sign are ubiquitous and influential phenomena in recognition and self-assembly processes. However, it has been recently revealed that specific attractive forces between ions with the same sign are relatively common. These forces can be strong enough to overcome the Coulomb repulsion between ions with the same sign, leading to the formation of stable anion⋯anion and cation⋯cation adducts. Hydroden bonds (HBs) are probably the best-known interaction that can effectively direct these counterintuitive assembly processes. In this review we discuss how σ-hole and π-hole bonds can break the paradigm of electrostatic repulsion between like-charges and effectively drive the self-assembly of anions into discrete as well as one-, two-, or three-dimensional adducts. σ-Hole and π-hole bonds are the attractive forces between regions of excess electron density in molecular entities (e.g., lone pairs or π bond orbitals) and regions of depleted electron density that are localized at the outer surface of bonded atoms opposite to the σ covalent bonds formed by atoms (σ-holes) and above and below the planar portions of molecular entities (π-holes). σ- and π-holes can be present on many different elements of the p and d block of the periodic table and the self-assembly processes driven by their presence can thus involve a wide diversity of mono- and di-anions. The formed homomeric and heteromeric adducts are typically stable in the solid phase and in polar solvents but metastable or unstable in the gas phase. The pivotal role of σ- and π-hole bonds in controlling anion⋯anion self-assembly is described in key biopharmacological systems and in molecular materials endowed with useful functional properties. [ABSTRACT FROM AUTHOR]

In the natural environment, plastics and microplastics (MPs) are difficult to break down due to their hydrophobicity, the presence of persistent covalent bonds, and their functional groups' resistance to attack. The destiny of both organic and inorganic pollutants at contaminated areas can be influenced by MPs ability to absorb them. Because of their enormous surface to volume ratio and chemical surface characteristics, MPs are able to absorb dangerous substances from their surroundings. Accordingly, the study's main objectives were to provide a concise review of characterization techniques of MP biodegradation techniques, including the nano‐enabled methods, and the gaps in current research were outlined. This review paper summarizes the degradation mechanism and efficiency of MPs in different circumstances. For the purpose of eliminating plastic pollution, this work will help for the further studies. [ABSTRACT FROM AUTHOR]

The preparation of mechanical robust organic room‐temperature phosphorescence (RTP) materials especially with white afterglow is attractive but rarely reported. Herein, a method to produce mechanical robust colorful RTP transparent wood (PTW) by infiltrating delignified wood with poly (vinyl alcohol) solutions containing arylboronic acids with various π conjugations is reported. The doubly rigid environment provided by the B─O covalent bonds and hydrogen bonds can stabilize the triplet excitons, leading to a ultralong lifetime of up to 2.13 s and excellent RTP emission stability (without obviously quenching over a month) of the target PTW. Besides, as a promising structural material for optical applications, the PTW shows combined advantages of multicolored persistent luminescence (from blue to green and then to red), good optical transmittance (≈90%), and striking mechanical strength (≈154 MPa). More importantly, by introducing appropriate amount of fluorescent dye rhodamine 6 G to the PTW with blue afterglow, white afterglow with a lifetime of 1.85 s is successfully achieve through triplet‐to‐singlet Förster resonance energy transfer. The PTW can function as afterglow window, anticounterfeiting label, and time delay lighting. This success paves the way for the development of mechanical robust, ecofriendly, and practical RTP materials. [ABSTRACT FROM AUTHOR]

A covalently bonded WO3/PEDOT hybrid nanorods array has been prepared through solvothermal, oil bath, and electrochemical deposition methods using KH57 as a coupling agent. The obtained WO3/PEDOT shows substantially increased electrochromic performance with an increased response speed (3.4 s for coloring and 1.2 s for bleaching), excellent optical modulation (86.7% at 633 nm), high coloration efficiency (122.0 cm2/C at 633 nm), and distinguished cyclic stability. It was found that the covalent bond interaction between WO3 and PEDOT plays an essential role in property enhancement. The covalently bonded inorganic/organic hybrid nanorods array may promise great potential in developing smart-display and energy-efficient materials and devices featuring low energy consumption, cost effectiveness, and environmental protection. [ABSTRACT FROM AUTHOR]

The proton exchange membrane water electrolyzer (PEMWE), crucial for green hydrogen production, is challenged by the scarcity and high cost of iridium‐based materials. Cobalt oxides, as ideal electrocatalysts for oxygen evolution reaction (OER), have not been extensively applied in PEMWE, due to extremely high voltage and poor stability at large current density, caused by complicated structural variations of cobalt compounds during the OER process. Thus, the authors sought to introduce chromium into a cobalt spinel (Co3O4) catalyst to regulate the electronic structure of cobalt, exhibiting a higher oxidation state and increased Co–O covalency with a stable structure. In‐depth operando characterizations and theoretical calculations revealed that the activated Co–O covalency and adaptable redox behavior are crucial for facilitating its OER activity. Both turnover frequency and mass activity of Cr‐doped Co3O4 (CoCr) at 1.67 V (vs RHE) increased by over eight times than those of as‐synthesized Co3O4. The obtained CoCr catalyst achieved 1500 mA cm−2 at 2.17 V and exhibited notable durability over extended operation periods – over 100 h at 500 mA cm−2 and 500 h at 100 mA cm−2, demonstrating promising application in the PEMWE industry. [ABSTRACT FROM AUTHOR]

Traditional electronic devices inevitably undergo degradation over time due to deformation, fatigue, or mechanical damage, ultimately resulting in device failure. To overcome this issue, researchers have pioneered the field of elastic electronics, incorporating higher mechanical tensile properties or strain resistance into electronic devices. Elastic materials, especially self‐healing elastomers (SHEs) are regarded as a crucial component in elastic electronics, offering the potential for restoring functionality and prolonging the lifespan of electronic devices. SHEs possess remarkable ability to tolerate significant deformation and utilize intrinsic dynamic chemical bonds to autonomously repair themselves from varying degrees of damage. The acquisition of intrinsic SHEs is key to the development of self‐healing elastic electronics and has attracted global attention. This review offers a comprehensive overview of the current advancements in self‐healing elastic electronics. First, the various self‐healing mechanisms present in elastomeric material systems are summarized. Second, the design strategies for constructing SHEs based on self‐healing mechanisms are reviewed in detail, with a particular emphasis on dynamic covalent and non‐covalent bonds. Subsequently, various optoelectronic applications of SHEs in elastic electronics are summarized. Finally, the challenges and prospects that lie ahead in order to foster further development in this rapidly growing field are outlined. [ABSTRACT FROM AUTHOR]

[Display omitted] Carbonyl or imine-based compounds have received a great deal of attention due to their high specific capacity and designability as cathodes for aqueous rechargeable organo-aluminum batteries. However, the inherent low conductivity and high solubility of carbonyl and imine-based compounds severely affect the cycling stability of aluminum batteries. Therefore, it is urgent to find an organic cathodes material with low solubility and good cycling performance. In this work, dibenzo[ a , c ]dibenzo[5,6:7,8]quinoxalino[2,3-i]phenazine-10,21-dione (DDQP) were synthesized by simple dehydration condensation to form new imine covalent bonds, which led to the synthesis of imine-conjugated backbone structures with carbonyl, extended π-conjugation planes, and increased active sites, resulting in increased specific capacities. Its storage mechanism with Al(OTF) 2 + has also been confirmed. This monovalent ion usually possesses a lower coulombic interaction, which leads to a reduced solubility of DDQP during redox processes and improves its cyclic stability. The specific capacity of DDQP is 252.22 mAh/g at a current density of 400 mA g−1. After cycling, the discharge specific capacity remains at 219 mAh/g. Surprisingly, the conductivity of the battery also is improved by this structure of multiple active sites. And it can be further confirmed by theoretical calculations that the synthesis of DDQP realigns the arrangement of the electron cloud, enhances the electron affinity, and reduces the energy gap. This study provides a new reference for improving the performance of aqueous organic aluminum batteries. [ABSTRACT FROM AUTHOR]

Cross‐linking of polymers is an efficient method to tailor the end‐use properties of polymer materials. Cross‐linking using a chemical agent, e.g., dicumyl peroxide (DCP), allows for a spatially uniform network formation in the melt state. In addition, it is also associated with side reactions which influence the final properties of the plastic part. This work investigates the influence of DCP concentration on the tribological properties of a cross‐linked low‐density polyethylene (LDPE) grade. In particular, high DCP concentrations up to 20 phr are chosen in order to explore the effect of a high degree of cross‐linking. The viscoelastic properties below and above the melting temperature are studied in detail to support the interpretation of the tribological results. Rheological investigations allow one to monitor the cross‐linking of the long‐chain branched LDPE. The data and the subsequent optical analysis show that wear already is significantly reduced at a low DCP concentration of 1 phr because of the covalent bonds caused by cross‐linking. A high DCP concentration of 20 phr yields an increase of coefficient of friction which can be explained by the low stiffness and the resulting high contact area in the case of highly cross‐linked LDPE. [ABSTRACT FROM AUTHOR]

The orthopedic application of Mg alloys suffers from excessive degradation. In this study, hydroxyapatite (HAP) nanoparticles are doped with MgO by high-energy ball milling, and then the obtained powders are compounded with WE43 powders and prepared into implants by laser powder bed fusion. During milling process, Mg2+ ions on MgO exchange some Ca2+ in HAP by mechanical collision and friction, which forms covalent bonds on the MgO/HAP interface. Subsequently, TEM observation showed that MgO on HAP forms semi-coherent interfaces with α-Mg, contributing to good bonding on the Mg/MgO interface. In this manner, strong bonding interfaces between ceramic particles and α-Mg were established, thereby preventing the agglomeration of nanoparticles. The well-dispersed ceramic particles provided more nucleation sites for apatite deposition, which benefits the formation of the passivation layer and thereby improves corrosion resistance. As a consequence, the composite exhibited a low corrosion density (20.1 ± 1.3 μA/cm2), high corrosion resistance (752.8 ± 19.7 Ω cm2), and low carrier concentration (1.28 ± 0.01 cm−3), indicating the formation of a more protective passivation layer. These findings suggested that the mHAP incorporated Mg composite may be a potential candidate for orthopedic implant. [ABSTRACT FROM AUTHOR]

Nanobiocatalysts (NBCs), which merge enzymes with nanomaterials, provide a potent method for improving enzyme durability, efficiency, and recyclability. This review highlights the use of eco-friendly synthesis methods to create sustainable nanomaterials for enzyme transport. We investigate different methods of immobilization, such as adsorption, ionic and covalent bonding, entrapment, and cross-linking, examining their pros and cons. The decreased environmental impact of green-synthesized nanomaterials from plants, bacteria, and fungi is emphasized. The review exhibits the various uses of NBCs in food industry, biofuel production, and bioremediation, showing how they can enhance effectiveness and eco-friendliness. Furthermore, we explore the potential impact of NBCs in biomedicine. In general, green nanobiocatalysts are a notable progression in enzyme technology, leading to environmentally-friendly and effective biocatalytic methods that have important impacts on industrial and biomedical fields. [ABSTRACT FROM AUTHOR]

For addressing the issue of limited durable antibacterial cotton fabric, this study developed and synthesized quaternary ammonium salt antimicrobial agents. The chemical structure was analyzed by FTIR and 1H NMR. The cotton fabric was subjected to surface modification techniques, such as pad-dry-cure, following the careful selection of appropriate quaternary ammonium salt. The chemical state and surface morphology were evaluated through XPS and SEM. Furthermore, the cotton fabric underwent comprehensive assessments, which included antibacterial testing, laundering cycle testing, evaluation of mechanical properties, and analysis of comfort performance. The results demonstrated that the treated cotton fabric achieved a high bacteriostatic and fungistatic rate of 99.99%, 87.5%, and 99.99% against S. aureus, E. coli, and C. albicans respectively even after 50 laundering cycles, while maintaining exceptional antibacterial effectiveness and laundering durability due to the formation of covalent bonds with the cotton fabric. The treated cotton fabric met AAA grade standards for antibacterial rate without causing any significant decline in mechanical properties. Furthermore, enhancements in hydrophilicity, softness, and wrinkle resistance were observed. [ABSTRACT FROM AUTHOR]

In this contribution, we reported the crosslinking of polyethylene (PE) with dynamic silyl ether bonds. First, polycyclooctene copolymers bearing hydroxyl groups were synthesized via the ring‐opening metathesis copolymerization of cyclooctene with 5‐norbornene‐2‐methanol. The hydroxy‐functionalized polycyclooctene copolymers were further hydrogenated into the corresponding hydroxy‐functionalized PE copolymers. The PE copolymers were allowed to react with 3‐isocyanatopropyltriethoxysilane to obtain the PE copolymers bearing triethoxysilane groups. By taking advantage of hydrolysis and condensation of triethoxysilane groups grafted onto PE chains, the PE copolymers were well crosslinked; polysilsesquioxane (PSSQ) segments behaved as the crosslinking linkages in the networks. Notably, the PE networks were reprocessable (or recyclable) while zinc trifluoromethanesulfonate [Zn(OTf)2] was incorporated. The reprocessing properties of the PE networks were quite dependent on the crosslinking densities. The reprocessing behavior of the networks is attributable to the introduction of two dynamic chemistries: (i) the metathesis of silyl ether bonds which was catalyzed with Zn(OTf)2 and (ii) transcarbamoylation of carbamates which was catalyzed with dibutyltin dilaurate. Owing to the crosslinking, the PE networks displayed excellent shape memory properties. For the shape memory networks, notably, the original shapes can be reprogrammed with the aid of the exchange of the dynamic covalent bonds introduced into the systems. [ABSTRACT FROM AUTHOR]

In the so-called Interacting Quantum Atoms (IQA) approach, the molecular energy is numerically decomposed as a sum of atomic and diatomic contributions. While proper formulations have been put forward for both Hartree–Fock and post-Hartree–Fock wavefunctions, this is not the case for the Kohn–Sham density functional theory (KS-DFT). In this work, we critically analyze the performance of two fully additive approaches for the IQA decomposition of the KS-DFT energy, namely, the one from Francisco et al., which uses atomic scaling factors, and that from Salvador and Mayer based upon the bond order density (SM-IQA). Atomic and diatomic exchange–correlation (xc) energy components are obtained for a molecular test set comprising different bond types and multiplicities and along the reaction coordinate of a Diels–Alder reaction. Both methodologies behave similarly for all systems considered. In general, the SM-IQA diatomic xc components are less negative than the Hartree–Fock ones, which is in good agreement with the known effect of electron correlation upon (most) covalent bonds. In addition, a new general scheme to minimize the numerical error of the sum of two-electron energy contributions (i.e., Coulomb and exact exchange) in the framework of overlapping atoms is described in detail. [ABSTRACT FROM AUTHOR]

We introduce N-P pair into the carbon matrix to construct N,P-C electrocatalyst by a facile pyrolysis strategy. Benefiting from the moderate adsorption energy of *OH on the active sites (C adjacent to P atom in N-P), the achieved N,P-C-1000 displays outstanding alkaline ORR performance and high power density primary liquid and solid ZABs. [Display omitted] • N-P pair was introduced into the carbon matrix to construct N,P-C electrocatalyst by a facile pyrolysis strategy. • The catalyst exhibits superior ORR activity with a E 1/2 of 0.83 V, comparable to that of commercial 20 wt% Pt/C. • Its C-2p orbit has higher interaction strength with the intermediates, thus reducing the overall reaction energy barrier. • High power density primary liquid and solid ZABs are achieved using N,P-C-1000 as cathodic catalysts. Developing sustainable metal-free carbon-based electrocatalysts is essential for the deployment of metal-air batteries such as zinc-air batteries (ZABs), among which doping of heteroatoms has attracted tremendous interest over the past decade. However, the effect of the heteroatom covalent bonds in carbon matrix on catalysis was neglected in most studies. Here, an efficient metal-free oxygen reduction reaction (ORR) catalyst is demonstrated by the N-P bonds anchored carbon (termed N,P-C-1000). The N,P-C-1000 catalyst exhibits superior specific surface area of 1362 m2 g−1 and ORR activity with a half-wave potential of 0.83 V, close to that of 20 wt% Pt/C. Theoretical computations reveal that the p-band center for C-2p orbit in N,P-C-1000 has higher interaction strength with the intermediates, thus reducing the overall reaction energy barrier. The N,P-C-1000 assembled primary ZAB can attain a large peak power density of 121.9 mW cm−2 and a steady discharge platform of ∼1.20 V throughout 120 h. Besides, when served as the cathodic catalyst in a solid-state ZAB, the battery shows flexibility, conspicuous open circuit potential (1.423 V), and high peak power density (85.8 mW cm−2). Our findings offer a strategy to tune the intrinsic structure of carbon-based catalysts for improved electrocatalytic performance and shed light on future catalysts design for energy storage technologies beyond batteries. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT)-1/2 is an efficient bandgap rectification method for DFT under local density approximation (LDA) or generalized gradient approximation. It was suggested that non-self-consistent DFT-1/2 should be used for highly ionic insulators like LiF, whereas self-consistent DFT-1/2 should still be used for other compounds. Nevertheless, there is no quantitative criterion prescribed for which implementation should work for an arbitrary insulator, which leads to severe ambiguity in this method. In this work, we analyze the impact of self-consistency in DFT-1/2 and shell DFT-1/2 calculations in insulators or semiconductors with ionic bonds, covalent bonds, and intermediate cases and show that self-consistency is required even for highly ionic insulators for globally better electronic structure details. The self-energy correction renders electrons more localized around the anions in self-consistent LDA-1/2. The well-known delocalization error of LDA is rectified, but with strong overcorrection, due to the presence of additional self-energy potential. However, in non-self-consistent LDA-1/2 calculations, the electron wave functions indicate that such localization is much more severe and beyond a reasonable range because the strong Coulomb repulsion is not counted in the Hamiltonian. Another common drawback of non-self-consistent LDA-1/2 is that the ionicity of the bonding gets substantially enhanced, and the bandgap can be enormously high in mixed ionic-covalent compounds like TiO2. [ABSTRACT FROM AUTHOR]

Oligosaccharides derived from agar, that is, agarooligosaccharides and neoagarooligosaccharides, have demonstrated various kinds of bioactivities which have been utilized in a variety of fields. Enzymatic hydrolysis is a feasible approach that principally allows for obtaining specific agar oligosaccharides in a sustainable way at an industrial scale. This review summarizes recent technologies employed to improve the properties of agarase. Additionally, the relationship between the degree of polymerization, bioactivities, and potential applications of agar-derived oligosaccharides for pharmaceutical, food, cosmetic, and agricultural industries are discussed. Engineered agarase exhibited general improvement of enzymatic performance, which is mostly achieved by truncation. Rational and semi-rational design assisted by computational methods present the latest strategy for agarase improvement with greatest potential to satisfy future industrial needs. Agarase immobilized on magnetic Fe3O4 nanoparticles via covalent bond formation showed characteristics well suited for industry. Additionally, albeit with the relationship between the degree of polymerization and versatile bioactivities like anti-oxidants, anti-inflammatory, anti-microbial agents, prebiotics and in skin care of agar-derived oligosaccharides are discussed here, further researches are still needed to unravel the complicated relationship between bioactivity and structure of the different oligosaccharides. [ABSTRACT FROM AUTHOR]

Potato starch can improve the 3D printability of surimi, but the molecular mechanism was not clear. The surimi from golden pompano was the research object and extracted myofibrillar protein from the surimi. The blend system was prepared with myofibrillar protein and potato starch and determined the rheological properties, microstructure, and intermolecular force. The 3D printing effect of surimi was evaluated. The fundamental reason why potato starch improved the 3D printability of surimi was analyzed. Results showed that the content of ionic bonds and hydrophobic interaction between protein molecules decreased, while the content of hydrogen bonds and disulfide covalent bonds increased, which promoted the conformational changes of amino acids in the side chain of protein molecules. When the mass ratio of myofibrillar protein to potato starch was 6:4, the link strength between rheological units of the blend system was 8 877. 2 Pa·s1 / z and the apparent viscosity was 2 818 Pa·s. At this time, the 3D printing effect of surimi was the best, and the printing accuracy and stability were 99. 6% and 98. 12% respectively. This study provided theoretical support for the formulation design and development of 3D-printed surimi products and had far-reaching practical significance for the wide application of 3D printing in the food industry. [ABSTRACT FROM AUTHOR]

Random and block polyarylates were synthesized using bisphenol A (BPA), bisphenol fluorene (BHPF), terephthaloyl chloride (TPC), and isophthaloyl chloride (IPC) as raw materials. The synthesis strategies of one-step and stepwise interfacial polymerization methods were adopted. Both types of polyarylates exhibited similar solubility, with block polyarylates showing slightly broader solvent selectivity. The presence of large sterically hindered fluorene groups in BHPF monomers rendered both block and random polyarylates amorphous by restricting the movement of macromolecular segments. The polyarylates demonstrated excellent thermal stability (T5% = around 490 °C) and a high glass transition temperature (Tg > 210 °C). As the covalent bonds of the monomer linkage showed no significant difference, the thermal stability of both types of products was similar. The glass transition temperature increased with an increase in TPC and diefluorene monomer content. The tensile strengths of the random and block polyarylate films ranged from 45.77–69.89 MPa and 49.49–55.29 MPa, respectively, indicating the high tensile strength of the resulting polyarylates. While the block polyarylates did not show significant differences from the conventional properties of random polyarylates, the synthesis of block polyarylates in this study represents a novel attempt, further highlighting the significant influence of the large pendant group of the main chain on the ordered arrangement of molecular segments. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION Recent studies have shown that the wettability of protein‐based emulsifiers is critical for emulsion stability. However, few studies have been conducted to investigate the effects of varying epigallocatechin gallate (EGCG) concentrations on the wettability of protein‐based emulsifiers. Additionally, limited studies have examined the effectiveness of soy protein–EGCG covalent complex nanoparticles with improved wettability as emulsifiers for stabilizing high‐oil‐phase (≥ 30%) curcumin emulsions.Soy protein isolate (SPI)–EGCG complex nanoparticles (SPIEn) with improved wettability were fabricated to stabilize high‐oil‐phase curcumin emulsions. The results showed that EGCG forms covalent bonds with SPI, which changes its secondary structure, enhances its surface charge, and improves its wettability. Moreover, SPIEn with 2.0 g L −1 EGCG (SPIEn‐2.0) exhibited a better three‐phase contact angle (56.8 ± 0.3o) and zeta potential (−27 mV) than SPI. SPIEn‐2.0 also facilitated the development of curcumin emulsion gels at an oil volume fraction of 0.5. Specifically, the enhanced network between droplets as a result of the packing effects and SPIEn‐2.0 with inherent antioxidant function was more effective at inhibiting curcumin degradation during long‐term storage and ultraviolet light exposure.The results of the present study indicate that SPIEn with 2.0 g L −1 EGCG (SPIEn‐2.0) comprises the optimum conditions for fabricating emulsifiers with improved wettability. Additionally, SPIEn‐0.2 can improve the physicochemical stability of high‐oil‐phase curcumin emulsions, suggesting a novel strategy to design and fabricate high‐oil‐phase emulsion for encapsulating bioactive compounds. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Quantum chemical calculations using ab initio methods at the MRCI+Q(8,9)/def2‐QZVPPD and CCSD(T)/def2‐QZVPPD levels as well as using density functional theory are reported for the diatomic molecules AeN− (Ae=Ca, Sr, Ba). The anions CaN− and SrN− have electronic triplet (3Π) ground states with nearly identical bond dissociation energies De ~57 kcal/mol calculated at the MRCI+Q(8,9)/def2‐QZVPPD level. In contrast, the heavier homologue BaN− has a singlet (1Σ+) ground state, which is only 1.1 kcal/mol below the triplet (3Σ−) state. The computed bond dissociation energy of (1Σ+) BaN− is 68.4 kcal/mol. The calculations at the CCSD(T)‐full/def2‐QZVPPD and BP86‐D3(BJ)/def2‐QZVPPD levels are in reasonable agreement with the MRCI+Q(8,9)/def2‐QZVPPD data, except for the singlet (1Σ+) state, which has a large multireference character. The calculated atomic partial charges given by the CM5, Voronoi and Hirshfeld methods suggest small to medium‐sized Ae←N− charge donation for most electronic states. In contrast, the NBO method predicts for all species medium to large Ae→N− electronic charge donation, which is due to the neglect of the (n)p AOs of Ae atoms as genuine valence orbitals. Neither the bond orders nor the bond lengths correlate with the bond dissociation energies. The EDA−NOCV calculations show that the heavier alkaline earth atoms Ca, Sr, Ba use their (n)s and (n‐1)d orbitals for covalent bonding. [ABSTRACT FROM AUTHOR]

Infrared transmitting materials (IRTMs) are prone to mechanical and corrosion damage during long‐time exposure to harsh outside environments. However, conventional IRTMs frequently lack self‐repairability that limit their lifespan. To address the limitation, thioctic acid‐based epoxy resins (TAEs) are developed from natural thioctic acid and commercial epoxy monomers. The double ring‐opening polymerization (ROP) reactions of thioctic acid and epoxy groups result in dual dynamic covalent bonds with varying bond energies containing relatively weak disulfide bonds and strong ester bonds. As compared with conventional covalent adaptable networks (CANs) that present rapid creep properties when heated, TAEs maintain their geometric stability during rapid self‐repairing at a mild temperature of 80 °C by enhancing network integrity through stable ester crosslinking points. The feature renders TAEs self‐repairing capability while maintaining precise geometrical dimensions, which is suitable for infrared transmitting devices. On the other hand, TAEs exhibit high near‐infrared transmittance (>80%). Therefore, TAEs with self‐repairability and high infrared transmittance demonstrate they can be used as superior polymeric IRTM. [ABSTRACT FROM AUTHOR]

In this work, an innovative dual cross‐linking strategy for carboxylated nitrile butadiene rubber (XNBR) latex using epoxy‐modified calcium silicate particles is presented. In their role as dual cross‐linker, the particles are able to form covalent bonds (nucleophilic ring opening of epoxy moieties) as well as ionic cross‐links (calcium ions of the inorganic core) across the carboxylic acid groups of the rubber. To characterize the curing efficiency, thin elastomer films are prepared by using a conventional coagulant dipping process and their cross‐link densities, curing kinetics, and tensile properties are investigated as a function of the concentration of the cross‐linker and curing time. The results show that latex films containing 5 phr of epoxy‐functional particles give the highest tensile strength, which is further improved by pre‐vulcanizing the liquid latex compound at 60°C for 30 min. The latex formulations are stable over 3 days and the pre‐cured films exhibit a high resistance against gamma sterilization and subsequent accelerated aging. Moreover, sterile films do not cause any skin irritation or skin sensitization reactions, showing the high potential of epoxy‐functional particles in the production of accelerator‐free hypoallergenic gloves. [ABSTRACT FROM AUTHOR]

Boron-doped polycyclic aromatic hydrocarbons exhibit excellent optical properties, and regulating their photophysical processes is a powerful strategy to understand the luminescence mechanism and develop new materials and applications. Herein, an electrochemically responsive B–O dynamic coordination bond is proposed, and used to regulate the photophysical processes of boron-nitrogen-doped polyaromatic hydrocarbons. The formation of the B–O coordination bond under a suitable voltage is confirmed by experiments and theoretical calculations, and B–O coordination bond can be broken back to the initial state under opposite voltage. The whole process is accompanied by reversible changes in photophysical properties. Further, electrofluorochromic devices are successfully prepared based on the above electrochemically responsive coordination bond. The success and harvest of this exploration are beneficial to understand the luminescence mechanism of boron-nitrogen-doped polyaromatic hydrocarbons, and provide ideas for design of dynamic covalent bonds and broaden material types and applications. Boron-doped polycyclic aromatic hydrocarbons with dynamic covalent bonds have interesting optical properties, but electricity-responsive bonds are less studied. Here, the authors report an electrochemically responsive B-O coordination bond with short switching time. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have emerged as promising renewable electrode materials for LIBs and gained significant attention, but their capacity has been limited by the densely packed 2D layer structures, low active site availability, and poor electronic conductivity. Combining COFs with high-conductivity MXenes is an effective strategy to enhance their electrochemical performance. Nevertheless, simply gluing them without conformal growth and covalent linkage restricts the number of redox-active sites and the structural stability of the composite. Therefore, in this study, a covalently assembled 3D COF on Ti3C2 MXenes (Ti3C2@COF) is synthesized and serves as an ultralong cycling electrode material for LIBs. Due to the covalent bonding between the COF and Ti3C2, the Ti3C2@COF composite exhibits excellent stability, good conductivity, and a unique 3D cavity structure that enables stable Li+ storage and rapid ion transport. As a result, the Ti3C2-supported 3D COF nanosheets deliver a high specific capacity of 490 mAh g−1 at 0.1 A g−1, along with an ultralong cyclability of 10,000 cycles at 1 A g−1. This work may inspire a wide range of 3D COF designs for high-performance electrode materials. [ABSTRACT FROM AUTHOR]

In this study, 3,4-ethylenedioxythiophene derivative conjugated monomer 4-(dihexylamino)-9,12-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-7H-benzo [de]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (EDOTBN) was synthesized and electropolymerized on pencil graphite electrode (PGE) to fabricate a highly stable and sensitive sensor for glucose detection for the first time. The structurally high conjugation of the monomer and the effect of increasing the conductivity of the gold nanoparticles increased the covalent bonding ability of the enzyme to the modified electrode surface and provided an excellent immobilization. PGE/p(EDOTBN)/AuNPs/GOx designed biosensor was characterized by a wide linear glucose determination range between 1.169 × 10–2 and 10 mM with a limit of detection of 0.008461 mM and a sensitivity of 38.365 µA/mMcm2. Furthermore, the prepared bioelectrode showed storage stability for 4 weeks. Recovery studies were also carried out to check the accuracy of the developed bioelectrode and the glucose concentration in commercial samples was determined accurately. [ABSTRACT FROM AUTHOR]

We develop a new type of heterostructure nanocomposite made of reduced graphene oxide-boron carbon nitride nanosheets (rGOBCN) by B–C covalent bonds. The rGO-BCN nanocomposite delivers a large specific surface and excellent electrochemical properties, and is then constructed into flexible fabric-based high-performance supercapacitor electrodes based on the microfluidic electrospinning technology. [ABSTRACT FROM AUTHOR]

Environmentally friendly crosslinked polymer networks feature degradable covalent or non‐covalent bonds, with many of them manifesting dynamic characteristics. These attributes enable convenient degradation, facile reprocessibility, and self‐healing capabilities. However, the inherent instability of these crosslinking bonds often compromises the mechanical properties of polymer networks, limiting their practical applications. In this context, environmentally friendly dual‐crosslinking polymer networks (denoted EF‐DCPNs) have emerged as promising alternatives to address this challenge. These materials effectively balance the need for high mechanical properties with the ability to degrade, recycle, and/or self‐heal. Despite their promising potential, investigations into EF‐DCPNs remain in their nascent stages, and several gaps and limitations persist. This Review provides a comprehensive overview of the synthesis, properties, and applications of recent progress in EF‐DCPNs. Firstly, synthetic routes to a rich variety of EF‐DCPNs possessing two distinct types of dynamic bonds (i.e. imine, disulfide, ester, hydrogen bond, coordination bond, and other bonds) are introduced. Subsequently, complex structure‐ and dynamic nature‐dependent mechanical, thermal, and electrical properties of EF‐DCPNs are discussed, followed by their exemplary applications in electronics and biotechnology. Finally, future research directions in this rapidly evolving field are outlined. [ABSTRACT FROM AUTHOR]

Incorporation of boron nitride (BN) into polymers is a promising method to obtain composites with high thermal conductivity, low dielectric constant (Dk), and dielectric loss (Df), while the practical applications are limited by the poor interface between BN and polymer because of surface energy mismatch and absence of covalent bond connection between them. Herein, polydopamine (PDA) with good adhesion is deposited onto the BN. Then, a different amount of silane coupling agent containing vinyl reactive groups is grafted onto PDA‐coated BN. In this way, the surface energy of modified BN (m‐BN) can be adjusted to ensure BN contacts well with polymers. Moreover, reactive groups were introduced on BN for further reaction. Subsequently, covalent bonds between the m‐BN and the polyphenylene oxide (PPO) were established in situ during the curing process. The effects of the m‐BN surface energy on interface quality and thermal conductivity of composites are investigated. The m‐BN/PPO composite achieves a through‐plane thermal conductivity of 5.87 W/m·K and a low Df value of 1.53 × 10−3, as well as a low coefficient of thermal expansion (CTE) value (7.8 ppm/K) when the m‐BN loading is 32.6 vol%. This research provides a simple and efficient strategy for fabricating high‐performance composites for high‐frequency applications. Highlights: Hexagonal boron nitride was modified successfully by combining non‐covalent and covalent modifications.Regulating surface energy and establishing covalent bonds enhances interface interaction between BN and polyphenylene oxide.Modified BN/polyphenylene oxide composites display improvements in thermal conductivity and dimensional stability as well as dielectric loss.Provides a feasible strategy for designing polymer composites with high thermal conductivity, dimensional stability, and low dielectric loss for 5G applications. [ABSTRACT FROM AUTHOR]

Scalable methods for improving the performance and stability of a field-effect transistor (FET) based on two-dimensional materials are crucial for its real applications. A scalable method of encapsulating the exfoliated MoS2 on the SiO2/Si substrate by hexamethyldisilazane (HMDS) is explored here for reducing the influence of interface traps and ambient contaminants. This leads to 25 times reduction in trap density, three times decrease in subthreshold swing, three times increase in the peak field-effect mobility, and a drastic reduction in hysteresis. This performance remains nearly the same after several weeks of ambient exposure of the device. This is attributed to the superhydrophobic nature of HMDS and the SiO2 surface hydrophobization by the formation of covalent bonds between the methyl groups of HMDS and silanol groups of SiO2. [ABSTRACT FROM AUTHOR]

The discovery of polar metals challenges long‐standing assumptions about the incompatibility between polar order and metallicity. However, despite recent progress, the mechanism allowing the coexistence of these supposedly forbidden properties remains unclear. Herein, carriers are introduced by constructing a symmetric polar/nonpolar interface in the KNbO3/BaTiO3 (KNO/BTO) superlattice (SL), enabling the coexistence of ferroelectric and metallic properties. A first‐principles analysis of the evolution of polar distortion and metallicity in the KNO/BTO SL under biaxial strain in the face to explore the dependence of the two at the microscopic level is performed. It is found that compressive strain enhances polarization distortion while reducing conductivity from three dimensions to two dimensions, indicating a weak coupling mechanism between carriers and polarization. Furthermore, it is shown that the presence of holes strengthens the TiO (NbO) covalent bonds, resulting in an unexpected enhancement of the polarization properties of the KNO/BTO SL. Therefore, it is proposed using the carrier screening effect and covalent bonding synergies as a framework for understanding the interaction between ferroelectricity and free carriers, rather than just a single factor therein. These results provide new theoretical insights for designing robust polar metals in perovskite ferroelectrics. [ABSTRACT FROM AUTHOR]

Nature owns the ability to construct structurally different polymers from the same monomers. While polymers can be classified as covalent polymers (CPs) and supramolecular polymers (SPs), it is still difficult to synthesize CPs and SPs using same monomers like nature do. Herein, M1 with two diazo salts on both the ends was designed. Additionally, hydroquinone was chosen to be M2 for the existence of two hydroxyl groups. When mixing at room temperature, M1 and M2 self‐assembled to SPs via N...H hydrogen bonds. In another way, upon the exposure to ultraviolet irradiation when blending M1 with M2, CPs were fabricated in the presence of covalent bonds. The excellent thermal stability of CPs was determined by TGA and DSC, while the great corrosion resistance of covalent polymers was detected by acid or alkali immersion. In this way, constructing two kinds of polymers using the same monomers was successfully achieved. This shows tremendous potential in fields of polymer science, supramolecular chemistry, which would boom the development of polymers. [ABSTRACT FROM AUTHOR]

The salt metathesis of a boryl-ethynyl lithium salt {[(HCDipN)2]B-CC-Li} with a monochlorosilylene [LSi(:)Cl; L = PhC(NtBu)2] produced an isolable boryl-ethynyl silylene {1; [(HCDipN)2]B–C≡C–Si(L)}. The Si(II) center in 1 possesses a nonbonding lone pair and forms a covalent bond with the ethynyl group. The characterization of 1 was carried out by multinuclear NMR spectroscopy, single-crystal X-ray structure analysis and DFT calculations. Additionally, a reactivity study of 1 was conducted towards oxygen-containing and aryl C–F substrates. [ABSTRACT FROM AUTHOR]

The regulation of topological structure of covalent adaptable networks (CANs) remains a challenge for epoxy CANs. Here, we report a strategy to develop strong and tough epoxy supramolecular thermosets with rapid reprocessability and room-temperature closed-loop recyclability. These thermosets were constructed from vanillin-based hyperbranched epoxy resin (VanEHBP) through the introduction of intermolecular hydrogen bonds and dual dynamic covalent bonds, as well as the formation of intramolecular and intermolecular cavities. The supramolecular structures confer remarkable energy dissipation capability of thermosets, leading to high toughness and strength. Due to the dynamic imine exchange and reversible noncovalent crosslinks, the thermosets can be rapidly and effectively reprocessed at 120 °C within 30 s. Importantly, the thermosets can be efficiently depolymerized at room temperature, and the recovered materials retain the structural integrity and mechanical properties of the original samples. This strategy may be employed to design tough, closed-loop recyclable epoxy thermosets for practical applications. The covalent crosslinked structure of epoxy thermosets difficult their reprocessability and recyclability. Here, the authors report a method for developing closed loop recycling of strong and tough epoxy supramolecular thermosets constructed with hyperbranched topological structure in an energy-saving and easy-to-conduct way. [ABSTRACT FROM AUTHOR]

Vitrimers offer a unique combination of mechanical performance, reprocessability, and recyclability that makes them highly promising for a wide range of applications. However, achieving dynamic behavior in vitrimeric materials at their intended usage temperatures, thus combining reprocessability with adaptivity through associative dynamic covalent bonds, represents an attractive but formidable objective. Herein, we couple boron‐nitrogen (B−N) dative bonds and B−O covalent bonds to generate a new class of vitrimers, boron‐nitrogen vitrimers (BNVs), to endow them with dynamic features at usage temperatures. Compared with boron‐ester vitrimers (BEVs) without B−N dative bonds, the BNVs with B−N dative bonds showcase enhanced mechanical performance. The excellent mechanical properties come from the synergistic effect of the dative B−N supramolecular polymer and covalent boron‐ester networks. Moreover, benefiting from the associative exchange of B−O dynamic covalent bonds above their topological freezing temperature (Tv), the resultant BNVs also possess the processability. This study leveraged the structural characteristics of a boron‐based vitrimer to achieve material reinforcement and toughness enhancement, simultaneously providing novel design concepts for the construction of new vitrimeric materials. [ABSTRACT FROM AUTHOR]

Bimetallic compounds containing direct metal‐group 13 element bonds have been shown to display unprecedented patterns of cooperative reactivity towards small molecules, which can be influenced by the identity of the group 13 element. In this context, we present here a systematic appraisal of group 13 metallo‐ligands of the type [(NON)E]− (NON=4,5‐bis(2,6‐diisopropylanilido)‐2,7‐di‐tert‐butyl‐9,9‐dimethylxanthene) for E=Al, Ga and In, through a comparison of structural and spectroscopic parameters associated with the trans L or X ligands in linear d10 complexes of the types LM{E(NON)} and XM′{E(NON)}. These studies are facilitated by convenient syntheses (from the In(I) precursor, InCp) of the potassium indyl species [{K(NON)In}⋅KCp]n (1) and [(18‐crown‐6)2K2Cp] [(NON)In] (1′), and lead to the first structural characterisation of Ag−In and Hg−E (E=Al, In) covalent bonds. The resulting structural, spectroscopic and quantum chemical probes of Ag/Hg complexes are consistent with markedly stronger σ‐donor capabilities of the aluminyl ligand, [(NON)Al]−, over its gallium and indium counterparts. [ABSTRACT FROM AUTHOR]

The surface of SBA‐15 mesoporous silica was modified by N‐hydroxyphthalimide (NHPI) moieties acting as immobilized active species for aerobic oxidation of alkylaromatic hydrocarbons. The incorporation was carried out by four original approaches: the grafting‐from and grafting‐onto techniques, using the presence of surface silanols enabling the formation of particularly stable O−Si−C bonds between the silica support and the organic modifier. The strategies involving the Heck coupling led to the formation of NHPI groups separated from the SiO2 surface by a vinyl linker, while one of the developed modification paths based on the grafting of an appropriate organosilane coupling agent resulted in the active phase devoid of this structural element. The successful course of the synthesis was verified by FTIR and 1H NMR measurements. Furthermore, the formed materials were examined in terms of their chemical composition (elemental analysis, thermal analysis), structure of surface groups (13C NMR, XPS), porosity (low‐temperature N2 adsorption), and tested as catalysts in the aerobic oxidation of p‐xylene at atmospheric pressure. The highest conversion and selectivity to p‐toluic acid were achieved using the catalyst with enhanced availability of non‐hydrolyzed NHPI groups in the pore system. The catalytic stability of the material was additionally confirmed in several subsequent reaction cycles. [ABSTRACT FROM AUTHOR]