Coordination Bonds Research Articles

An efficient PCN-224/graphene aerogel-based extraction method for monitoring the degradation of organophosphorus pesticides in juice

An efficient PCN-224/graphene aerogel modified silica (PCN-224/GA@Sil)-based extraction method was established for monitoring the degradation process of two organophosphorus pesticides (OPPs) in juice. PCN-224/GA@Sil exhibited higher surface area (307.35 m2 g-1) than graphene oxide modified silica (254.09 m2 g-1). The introduction of PCN-224 endowed the sorbent with excellent adsorption specificity towards OPPs due to the ZrˑˑˑS/O coordination bond. PCN-224 exhibited relatively higher theoretical adsorption energies of PCN-224 towards fenitrothion and fenthion were 0.68 eV and -0.31 eV. The established PCN-224/GA@Sil-HPLC method showed the linearity of 0.2-500 μg L-1 for analytes. The matrix effects in juice were 9.68 % and 3.61 % for fenitrothion and fenthion. Finally, it was used for the sample pretreatment of juice preventing interference from food matrices to monitor the degradation of two OPPs. A combination method of ultrasound and xenon lamp was adopted to degrade fenitrothion and fenthion displaying the synergistic effect (SE=2.12, 1.39).

Rational design of a zinc-dependence secondary alcohol dehydrogenase to boost its oxidation activity for α-hydroxyketones biosynthesis

α-Hydroxyketones, which have significant industrial applications, can be sustainably synthesized through the oxidation of secondary alcohols using secondary alcohol dehydrogenase (SADH). However, the activity of the SADH oxidation reaction is generally low, making it unsuitable for large-scale production. In this study, a rational design approach was employed to computationally engineer SADH derived from Ogataea parapolymorpha (OpSADH), significantly enhancing its oxidation activity towards (R)-1,2-propanediol (PDO). The mutant M2 (S222T/S316A) exhibited a 14.2-fold increase in specific enzyme activity compared to the wild type (WT) and was employed as a catalyst for high-concentration hydroxyacetone production, facilitated by an NAD+ regeneration system. By applying an appropriate Zn2+ ion force field in molecular dynamics (MD) simulations, it was found that two mutation sites could stabilize the conformations of NAD+ and PDO, thereby revealing the molecular mechanism behind the enhanced activity of this metalloenzyme mutant. Notably, we first uncovered the dynamic mechanism by which four key residues (Cys39, His75, Glu76, and Glu175) and PDO within the active pocket contribute to the formation of coordination bonds with Zn2+. The findings of this study provide robust support for researching the catalytic mechanisms and dynamics processes of metalloenzymes.

Nanoengineering of Phosphate/Phosphonate Drugs via Competitive Replacement with Metal‐Phenolic Networks to Overcome Breast Tumor with Lung and Bone Metastasis

AbstractPhosphate and phosphonate drugs are vital in building organisms, regulating physiological processes, and exhibiting diverse biological activities, including antiviral, antibacterial, antineoplastic, and enzyme‐inhibitory effects. However, their therapeutic potential is limited by the lack of advanced nanoengineering technologies. Herein, a competitive coordination strategy for nanoengineering phosphate/phosphonate drugs is introduced. By leveraging the difference in coordination capabilities between polyphenols and phosphates/phosphonates with metal ions, various phosphate/phosphonate‐based nanodrugs using metal‐phenolic networks (MPNs) as templates and phosphate/phosphonate drugs as competitive agents are constructed. The dynamic nature of these coordination bonds imparts stimuli‐responsiveness to the nanodrugs, allowing for targeted release and therapy. As a proof of concept, Fe3+ and galangin are used to form the MPN template, zoledronic acid and cGAMP as competitive agents, and DOX as the loaded drug to construct DOX@Fe‐galangin@Fe‐zoledronic acid‐cGAMP nanodrugs. The results demonstrate that, by triggering pyroptosis and activating the cGAS‐STING pathway, the nanodrugs exhibit potent cytotoxicity and accurate selectivity in eradicating orthotopic breast tumors, and activate an antitumor immune response against lung and bone metastases. Because the competitive coordination strategy is applicable to a variety of phosphate/phosphonate agents, it holds significant potential for enhancing the clinical efficacy of phosphate/phosphonate drugs and advancing nanodrug development for complex therapeutic applications.

Vertically Expanded Crystalline Porous Covalent Organic Frameworks.

Covalent organic frameworks (COFs) can be developed for molecular confinement and separation. However, their proximate π stacks limit the interlayer distance to be only 3-6 Å, which is too small for guests to enter. As a result, COFs block access to the x-y space and limit guest entry/exit strictly to only the pores along the z direction. Therefore, the extended faces of each layer are hidden between layers, precluding any interactions with guest molecules. Here, we report a strategy for opening interlayer spaces of COFs to attain newly accessible nanospaces between layers. This becomes possible using coordination bonds to replace the conventional π-π stacks between layers. We demonstrate this concept by synthesizing two-dimensional covalent cobalt(II) porphyrin layers through topology-guided polymerization, which were piled up by bidentate axial pillars through coordination bonds with cobalt(II) porphyrin along the z direction, assembling vertically expanded COFs via a one-pot reaction. The resultant frameworks separate the layers with axial pillars and create discrete apertures between layers defined by the molecular length of the pillars. Consequently, the originally inaccessible interlayers are open for guest access, while the polygonal π planes are exposed to trigger various supramolecular interactions. Vapor sorption, breakthrough experiments, and computational studies mutually revealed that the vertically expanded frameworks with optimal interlayer slits induce additional interactions to discriminate benzene and cyclohexane and separate their mixtures efficiently under ambient conditions.

Palladium catalyzed ortho-C(sp2)-H activation/cyclization of aryl amines assisted by imine and vinylacetic acid.

Palladium-catalyzed directed C - H functionalization/cyclization is an effective approach for synthesizing nitrogen heterocycles. Imine, known for its ease of installation/removal, has been extensively used in the C-H activation of aldehydes, ketones, and alkylamines. Nevertheless, it has been rarely explored in the C(sp2)-H activation of aryl amines because of the generation of a strained four-membered palladacycle. Herein, an imine directed palladium catalyzed C(sp2)-H functionalization of aryl amines assisted by vinylacetic acid is established, providing access to a variety of γ-lactone fused tetrahydroquinolines under mild reaction conditions. The methodology demonstrates broad substrate scope and good functional group tolerance, representing notable advancement in organic synthesis. Mechanistic experiments are performed to clarify how the C(sp2)-H activation occurs, indicating the crucial role of vinylacetic acid. DFT calculations supports the observations, elucidating the strained four-membered ring C-H activation barrier is overcome via coordination and hydrogen bond interaction of vinylacetic acid.

Alginate/Chitosan Complex Fibers Reinforcement and Their Mechanical Transition Continuum With Water Uptake Increasing.

Living tissues span a remarkable spectrum of modulus ranging from the level of Pa to GPa in a water-rich environment. Constructing soft and hard materials that match the mechanics of tissues and researching mechanical transition in water, are beneficial for their biological applications. Here, using polyelectrolyte complex fiber as a model system and reinforcing the fiber by stepwisely introducing additional coordination and covalent bonds, this investigated that the water effect on mechanical transition behaviors. Alginate/chitosan fiber (AC fiber) has a single electrostatic bond and shows continuous mechanical transition containing a glassy state, rubbery state, and terminal relaxation (initial modulus lower than 10MPa) in aqueous solution. Alginate/chitosan/calcium fiber (ACC fiber) has both electrostatic and coordination bonds, which shows the behavior of hard rubber (initial modulus 100MPa) when water reaches equilibrium. Alginate/chitosan/calcium/polydopamine fiber (ACCP fiber) with triple bonds, including electrostatic, coordination, and covalent bonds, exhibits the behavior like ductile plastics in aqueous solution (initial modulus 1000MPa). This work not only provides important insight into the toughening mechanism of polyelectrolyte complexes in water but also contributes to the preparation of tissue adaptive implantations.

Deep-Eutectic-Solvent-Decorated Metal–Organic Framework for Food and Environmental Sample Preparation

Deep eutectic solvent (DES) is distinguished by its unique solvent properties, chemical stability, and eco-friendly nature, which are pivotal in a spectrum of chemical processes. It enhances the sample preparation process by increasing efficiency and minimizing the environmental impact. Metal–organic frameworks (MOFs), which are porous structures formed through coordination bonds between metal ions and organic ligands, are defined by their adjustable pore dimensions, extensive surface areas, and customizable architectures. The integration of DES within MOF to create DES@MOF capitalizes on the beneficial attributes of both materials, augmenting MOFs’ stability and versatility while providing a multifunctional carrier for DES. This composite material is both highly stable and readily tunable, establishing it as a leading contender for applications in sample preparation for food and environmental samples. This comprehensive review explores the application of DES-decorated MOF in food and environmental sample preparation and highlights the expansive potential of DES@MOF in diverse fields. We provide a detailed analysis of the characteristics of DES@MOF and its individual components, methods for decorating MOFs with DES, the advantages of these composite materials in sample pretreatment, and their specific applications in food safety and environmental monitoring. DESs are employed to modify MOFs, offering a multitude of benefits that can substantially improve the overall performance and applicability of MOFs. The review also discusses current challenges and future directions in this field, offering valuable insights for further research and development. The synergistic effects of DES and MOFs offer new opportunities for applications in food safety and other areas, leading to the development of more efficient, sensitive, and environmentally friendly analytical methods. This collaboration paves the way for sustainable technologies and innovative solutions to complex challenges.

Zipper‐Like Dynamic Switching of Coordination Bonds Gives a Polar Bimetallic Halide Toward Self‐Driven X‐Ray Detection

AbstractPolar molecular crystals hold a promise for controlling bulk physical properties originated in their unique switchable polarity via structural transformation. However, the mechanisms for switching polarization are mainly limited to displacive and disorder‐order phase transitions, which rarely involve the reconstruction of chemical bonds. Here, we have switched and tuned electric polarization in a bimetallic halide, (Neopentylammonium)4AgBiBr8 (1), as verified by light‐excited pyroelectric effect. Most notably, its Ag−Br coordination bonds show a zipper‐like dynamic switching behavior from the ‘locked’ to ‘unlocked’ state, namely, reconstruction of chemical bonds. Coupling with the dynamic ordering of organic cations, this bond‐switching transition makes a contribution to switchable polarization of 1. As expected, its polarity creates pyroelectric effect for self‐driven X‐ray detection with high sensitivity (3.8×103 μC Gy−1 cm−2) and low limit of detection (4.8 nGy s−1). This work on the bond‐switching mechanism provides an avenue to design polar molecular candidate for smart optoelectronic devices.

Zipper-Like Dynamic Switching of Coordination Bonds Gives a Polar Bimetallic Halide Toward Self-Driven X-Ray Detection.

Polar molecular crystals hold a promise for controlling bulk physical properties originated in their unique switchable polarity via structural transformation. However, the mechanisms for switching polarization are mainly limited to displacive and disorder-order phase transitions, which rarely involve the reconstruction of chemical bonds. Here, we have switched and tuned electric polarization in a bimetallic halide, (Neopentylammonium)4AgBiBr8 (1), as verified by light-excited pyroelectric effect. Most notably, its Ag-Br coordination bonds show a zipper-like dynamic switching behavior from the 'locked' to 'unlocked' state, namely, reconstruction of chemical bonds. Coupling with the dynamic ordering of organic cations, this bond-switching transition makes a contribution to switchable polarization of 1. As expected, its polarity creates pyroelectric effect for self-driven X-ray detection with high sensitivity (3.8×103 μC Gy-1 cm-2) and low limit of detection (4.8 nGy s-1). This work on the bond-switching mechanism provides an avenue to design polar molecular candidate for smart optoelectronic devices.

Spatiotemporal Proximity-Enhanced Biocatalytic Cascades Within Metal-Organic Frameworks for Wearable and Theranostic Applications.

Enzymatic catalysis, particularly multi-enzyme cascade catalytic, is often limited by the spatial and temporal separation of enzymes and their signal substrates. Herein, a facile method for producing a spatiotemporal proximity-enhanced biocatalytic cascade system is introduced by encasing enzymes within metal-organic frameworks (MOFs) that are modulated with sulfonic acid-functionalized signal substrates. The modulated behavior relies on the sulfonic acid groups coordinated with Zn2+. As a proof of concept, by utilizing 2,2'-Azinobis (3-ethylbenzothiazoline-6-sulfonic acid ammonium salt) (ABTS), a widely-used signal substrate for horseradish peroxidase, two-enzyme/substrate, and three-enzyme/substrate MOFs, which demonstrated a 7.4- and 10.2-fold increase in biocatalytic efficiency over free systems are successfully synthesized. Incorporating the synthesized MOFs into homemade wearable patches and in vivo settings, noninvasive sweat glucose colorimetric detection and photoacoustic imaging-guided photothermal tumor therapy are enabled, respectively. This advancement stems from the newly established coordinative bonds between Zn2+ centers and substrates' sulfonic acid groups, which negates the need for additional signal substrates, thereby not only enhancing but also streamlining bioapplication processes.

High-Strength, Self-Healing Copolymers of Acrylamide and Acrylic Acid with Co(II), Ni(II), and Cu(II) Complexes of 4′-Phenyl-2,2′:6′,2″-terpyridine: Preparation, Structure, Properties, and Autonomous and pH-Triggered Healing

The utilization of self-healing polymers is a promising way of solving problems associated with the wear and tear of polymer products, such as those caused by mechanical stress or environmental factors. In this study, a series of novel self-healing, high-strength copolymers of acrylamide, acrylic acid, and novel acrylic complexes of 4′-phenyl-2,2′:6′,2″-terpyridine [Co(II), Ni(II), and Cu(II)] was prepared. A systematic study of the composition and properties of the obtained polymers was carried out using a variety of physicochemical techniques (elemental analysis, gel permeation chromatography (GPC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR), ultraviolet-visible spectroscopy (UV-vis), small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), confocal laser scanning microscopy (CLSM), and tensile testing). All metallopolymer samples exhibit autonomous intrinsic healing along with maintaining high tensile strength values (for some samples, the initial tensile strength exceeded 100 MPa). The best values of healing efficiency are possessed by metallopolymers with a nickel complex (up to 83%), which is most likely due to the highest lability of the metal–heteroatom coordination bonds. The example of this system shows the ability to re-heal with negligible deterioration of the mechanical properties. The possibility of tuning the mechanical properties of self-healing films through the use of different metal ions has been demonstrated.

Pd3 Sandwich Complexes with π-Cyclic Ligands: Theoretical Insight into Stability, Face-Capping Coordination Bond, Trans-Influence, and Backside-Ligand Effect.

Triangle Pd3 sandwich complexes with two face-capping π-cyclic ligands, [Pd3(Cm)(Cn)L3]2+ [L = acetonitrile; Cm, Cn = benzene, cycloheptatriene (CHT), cyclooctatetraene (COT), and [2.2]paracyclophane (PCP)], are theoretically investigated. The stability increases in the order [Pd3(C6H6)2L3]2+ ∼ [Pd3(C6H4Me2P)2L3]2+ (C6H4Me2P = p-xylene) < [Pd3(COT)2L3]2+ < [Pd3(CHT)2L3]2+ < [Pd3(PCP)2L3]2+ and [Pd3(C6H6)2L3]2+ ∼ [Pd3(C6H6)(C6H4Me2P)L3]2+ < [Pd3(C6H6)(PCP)L3]2+ < [Pd3(C6H6)(CHT)L3]2+ < [Pd3(C6H6)(COT)L3]2+ < [Pd3(CHT)(PCP)L3]2+ < [Pd3(COT)(PCP)L3]2+, where "bold" represents an experimentally isolated complex. Based on these results, we succeeded in synthesizing a new complex [Pd3(CHT)(PCP)L3]2+. Geometrical features suggest that benzene and PCP interact with one Pd atom using one C═C double bond and with two other Pd atoms using the other C═C double bond in the bridging manner. CHT interacts with three Pd atoms using three C═C double bonds. COT interacts with three Pd atoms using three C═C double bonds in [Pd3(COT)2L3]2+ and using π-allyl type MOs with additional participation of two C═C π bonds in [Pd3(C6H6)(COT)L3]2+. CHT and PCP weaken the benzene coordination bond in [Pd3(C6H6)(CHT)L3]2+ and [Pd3(C6H6)(PCP)L3]2+ like trans-influence. Unprecedentedly, COT strengthens the benzene coordination bond in [Pd3(C6H6)(COT)L3]2+. This "backside-ligand effect" arises from the characteristic coordination bond of the COT, which is elucidated based on the orbital interaction between the COT and Pd3 triangle.

Vertically Expanded Covalent Organic Frameworks for Photocatalytic Water Oxidation into Oxygen

Covalent organic frameworks with unique π architectures and pores could be developed as photocatalysts for transformations. However, they usually form π‐stacking layers, so that only surface layers function in photocatalysis. Here we report a strategy for developing vertically expanded frameworks to expose originally inaccessible active sites hidden in layers to catalysis. We designed covalently linked two‐dimensional cobalt(II) porphyrin layers and explored coordination bonds to connect the cobalt(II) porphyrin layers with bidentate ligands via a three‐component one‐pot polymerization. The frameworks expand the interlayer space greatly, where both the up and down faces of each cobalt(II) porphyrin layer are exposed to reactants. Unexpectedly, the vertically expanded frameworks increase skeleton oxidation potentials, decrease exciton dissociation energy, improve pore hydrophilicity and affinity to water, and facilitate water delivery. Remarkably, these positive effects work collectively in the photocatalysis of water oxidation into oxygen, with an oxygen production rate of 1155 µmol g−1 h−1, a quantum efficiency of 1.24% at 450 nm, and a turnover frequency of 1.39 h−1, which is even 5.1‐fold as high as that of the π‐stacked frameworks and ranks them the most effective photocatalysts. This strategy offers a new platform for designing layer frameworks to build various catalytic systems for chemical transformations.

Vertically Expanded Covalent Organic Frameworks for Photocatalytic Water Oxidation into Oxygen.

Covalent organic frameworks with unique π architectures and pores could be developed as photocatalysts for transformations. However, they usually form π-stacking layers, so that only surface layers function in photocatalysis. Here we report a strategy for developing vertically expanded frameworks to expose originally inaccessible active sites hidden in layers to catalysis. We designed covalently linked two-dimensional cobalt(II) porphyrin layers and explored coordination bonds to connect the cobalt(II) porphyrin layers with bidentate ligands via a three-component one-pot polymerization. The frameworks expand the interlayer space greatly, where both the up and down faces of each cobalt(II) porphyrin layer are exposed to reactants. Unexpectedly, the vertically expanded frameworks increase skeleton oxidation potentials, decrease exciton dissociation energy, improve pore hydrophilicity and affinity to water, and facilitate water delivery. Remarkably, these positive effects work collectively in the photocatalysis of water oxidation into oxygen, with an oxygen production rate of 1155 µmol g-1 h-1, a quantum efficiency of 1.24% at 450 nm, and a turnover frequency of 1.39 h-1, which is even 5.1-fold as high as that of the π-stacked frameworks and ranks them the most effective photocatalysts. This strategy offers a new platform for designing layer frameworks to build various catalytic systems for chemical transformations.

Exploring Interatomic Electron Transfer and Metal-Ligand Binding Mechanism in Trimethylenemethane Iron Tricarbonyl: Insights from Potentials per Electron and Corresponding Force Density Fields.

This study employs an analysis of the per-electron potentials and the superposition of the electrostatic and kinetic force fields, Fes(r) and Fk(r), and the gradients of the potential energy and one-electron densities to investigate the binding mechanism in trimethylenemethane iron tricarbonyl complex (TMM)Fe(CO)3. Our approach permits the delineation of the "ligand-binding" force field generated by the metal nucleus but partially operating within the ligand atoms. A mechanical rationale for metal-ligand interactions is thus presented: In the corresponding area, the attractive force Fes(r) provides the backdrop against which the homotropic static force (r) and the heterotropic kinetic force Fk(r) exert attractive and repulsive influences, respectively, toward the metal nucleus on a portion of the electrons belonging to the ligand atoms. This area thus represents electron sharing, which emerges as a quantum chemical response against the metal-to-ligand electron transfer. It has been demonstrated that the response is facilitated by the decreased potential energy density in the vicinity of the interatomic surface. Our findings indicate that the polar coordination bonds in (TMM)Fe(CO)3 exhibit notable quantum chemical responses. However, the previously described nonbonded contact also features an unexpectedly pronounced response, despite the absence of a bond path. It can be proposed that the unforeseen response is a consequence of the formation of the 18-electron, closed valence shell, rather than an indication of the establishment of an organometallic chemical bond.

Double-Bridging Increases the Stability of Zinc(II) Metal-Organic Cages.

A key feature of coordination cages is the dynamic nature of their coordinative bonds, which facilitates the synthesis of complex polyhedral structures and their post-assembly modification. However, this dynamic nature can limit cage stability. Increasing cage robustness is important for real-world use cases. Here we introduce a double-bridging strategy to increase cage stability, where designed pairs of bifunctional subcomponents combine to generate rectangular tetratopic ligands within pseudo-cubic Zn8L6 cages. These cages withstand transmetalation, the addition of competing ligands, and nucleophilic imines, under conditions where their single-bridged congeners decompose. Our approach not only increases the stability and robustness of the cages while maintaining their polyhedral structure, but also enables the incorporation of additional functional units in proximity to the cavity. The double-bridging strategy also facilitates the synthesis of larger cages, which are inaccessible as single-bridged congeners.

Coordination-Induced Magnetism Strategy for Highly Selective and Efficient Uranium Separation.

Highly efficient separation of dispersed uranium is important for the sustainable development of nuclear industry, and adsorption is the most recognized approach. However, there are many coexisting interfering metal ions that compete with uranyl ion for the chelating ligands in the adsorbents and lead to low separation selectivity and efficiency. Herein, a coordination-induced magnetism strategy is presented for the separation of uranium based on the conversion of diamagnetic cyanoferrocene (Fc-CN) nanocrystals to uranium-containing magnetic recoverable ferromagnetic aggregates. Different from previous adsorption strategies, this strategy combines the mechanisms of photocatalytic uranium enrichment and chemical uranium adsorption. Under light irradiation, electron of Fe(II) in Fc-CN is excited and transfers to uranyl ion via the cyano group to form tight coordination bond between N atom in cyano group and uranium. This phenomenon is unique for uranyl ion, and thus, a high uranium removal rate of 97.98% is achieved in simulated nuclear wastewater with the presence of tremendous interfering ions, proving its highly selective and efficient uranium separation performance. The ability to form highly stable magnetic aggregates via photoinduced interaction between Fc-CN and uranium enriches the understanding on the chemical properties of Fc-CN and uranium.

Beating the Odds with Binuclear N‐Heterocyclic Carbene Metallacycles: A Practical and Efficient Full‐Color Tunable Fluorescence System

AbstractAchieving full‐color emission with just two emitters presents a significant challenge. Two N‐heterocyclic carbene metallacycles (NHC‐M; M ═ Ag, Au) featuring a tetraphenylethene core, combining covalent and coordination bonds are synthesized to restrict rotation within the NHC‐M‐BC (BC = bicyclic) metallacycles and greatly enhanced their quantum yields. The enhancement is accomplished by adjusting the CH3CN/H2O solvent mixture, allowing emission tuning from blue to green for NHC‐Ag‐BC. Further diversification of the emission spectrum, including access to high‐quality white light (CIE coordinates 0.33, 0.34), is facilitated through the addition of sulforhodamine B via fluorescence resonance energy transfer (FRET). The compatibility of NHC‐Ag‐BC with agarose gel extends its applicability to UV‐LEDs chromic coatings, as well as information encryption and anti‐counterfeiting materials. The results underscore the viability of dual‐fluorophore systems for achieving full‐color emission and highlight the potential for developing versatile, multi‐colored functional materials.

A multiple physical crosslinked cellulose-based bioplastics with robust mechanical and thermal stability.

The widespread use of traditional petroleum-based plastics has created an environmental crisis and health hazard, so there is an urgent need for bioplastics with excellent performance. However, fabricating of robust mechanical properties and heat resistance bioplastics in an efficient way has remained an enormous challenge. Herein, we proposed a strategy for the synergistic preparation of high-performance bioplastics with multiple physical crosslinking network structures via noncovalent and coordination bonds. In this strategy, carboxylated cellulose nanofibers (CNFs) and the polyphenol structures of tannic acid (TA) interacted noncovalently to create network structures; the bioplastic immersed in Ca2+ solution formed ionic crosslinked networks and TA-Ca coordination bonds. The synergistic effect of multiple network structures composed of hydrogen and coordination bonds made cellulose-based bioplastics have dense structures and robust tensile strength (114.2 MPa), while bioplastics had the characteristics of high transparency and superior thermal stability. Furthermore, the laminated composites formed by the bioplastic and PVA could support 1000 g easily, which allowed it to be used as weighing application. Thus, the proposed multiple physical crosslinking strategy provides a method for developing cellulose-based bioplastics with excellent performance, which offers a new approach for the subsequent development of sustainable green materials.

Redox active metallene anchored amino-functionalized cellulose composite for electrochemical capture and conversion of chromium

Considering the ubiquity and high toxicity of Cr(VI) species for destroying a sustainable environment, developing energy-efficient method for capturing and detoxifying chromium [Cr(VI) → Cr(III)] is imperative. Herein, ferrocene (Fc) was combined with carboxymethyl cellulose (CMC) and polyethyleneimine (PEI) for Cr(VI) remediation. Fc species possessed reversible redox behavior and low ionization potential, yet it faced challenges with conductivity and stability. Results revealed that, PEI facilitated the binding of Fc within the CMC through electrostatic interactions or coordination bonds, ensuring the good dispersion and stability of Fc. When applied in the electrochemical adsorption of Cr(VI), the combination created a synergistic effect. The presence of Fc and PEI boosted the electrochemical performance by providing faster electronic and ionic transportation, higher specific capacitance coupled with improved electrode-electrolyte interactions, leading to a higher Cr(VI) adsorption capacity over CMC/PEI/Fc (280.5 mg/g) compared to those over CMC and CMC/PEI. The interactions between the Cr(VI) and electrode included the electrosorption, electrostatic interaction of protonated PEI and oxidized Fc species. When the electric field was reversed, the Cr(VI) was electrostatic repulsed and electrocatalytic reduced to Cr(III) with a reduction rate of 85.4 %. This work promoted the development of effective electrosorption materials suitable for complete Cr(VI) removal and detoxification.