Strong Coordination Bonds Research Articles

Roles of ESIPT and TICT in the Photophysical Process of a Ratiometric Fluorescence Sensor for Al3.

Precise detection of Al3+ with the aid of a fluorescence sensor is of fundamental importance in the fields of water pollution control and food safety. A comprehensive understanding of the photophysical process of the sensor as well as its underlying detection mechanism is a precondition for the design of highly efficient sensors. This contribution performs a thorough investigation of the ratiometric fluorescence sensing mechanism of an Al3+ sensor with the aid of density functional theory and time-dependent density functional theory. Two excited-state intramolecular proton transfer (ESIPT) processes are observed on the S1 state potential energy surface, which leads to emission around 565 nm. A twisted intramolecular charge transfer state is observed after one of the ESIPT processes via cis-trans isomerization of the C═N bond. However, the large energy barrier hinders its occurrence, which is quite unusual. Al3+ is found to form three strong coordination bonds with the sensor, which eliminates ESIPT processes and induces a significant blue shift of the emission spectrum to 480 nm. The origination of the sensor's selectivity is also uncovered by investigating the interaction between the sensor and interfering metal ions.

A bidirectional-modification strategy for enhancing the reliability of thermoplastic-metal hybrid joint from atomic-scale

In this study, a strategy towards thermoplastic-metal hybrid joint via bidirectional modification for high reliability was designed. The chemical bond behavior and conditions at the interface were explored from atomic scale using density functional theory (DFT) calculation. Based on the bonding mechanism, the AZ31B alloy was oxidized and the carboxyl groups (COOH) were introduced in the resin chain to improve the strength of chemical bond. The mechanical property of the designed joint was significantly improved and the tensile-shear strength achieved 22.7 MPa after bidirectional modification, reaching 4.5 times that of untreated joints. It was mainly attributed to the generation of metal-carboxylate bridging complex—a typical strong coordination bond formed between two O atoms in COOH and two diagonal magnesium atoms in MgO. Experimental evidence also suggested the generation of new chemical bond at the CFRTP/AZ31B interface. Finally, the bidirectional modification was proved to be an efficient and reliable method with high industrial adaptability. The current work opened up a novel direction for reliability promotion of thermoplastic-metal hybrid structures.

Preparation of transparent and flexible regenerated kenaf CNF composite films with curcumin-metal complex for food packaging applications

Cellulose nanofibers (CNF) derived from kenaf plant were combined with curcumin (Cur)-metal complexes to produce regenerated composite films. Cur was used to synthesize homoleptic Cur-metal complexes with diamagnetic Zn(II) and paramagnetic Cu(II) metal ions. Cur-Zn(II) complex and Cur-Cu(II) complex were synthesized under the same reaction conditions to check the synergistic effect of engaging the diketone electrons of Cur with strong coordination bonds with two different metal ions. The synthesized Cur-metal complexes were used as fillers to produce CNF composite films for biodegradable food packaging film. Results showed that the Cur-Zn(II) complex-loaded CNF composite films exhibit higher antioxidant activity than other films whereas Cur-Cu(II) complex-loaded CNF composite films showed prominent antibacterial activity against foodborne pathogenic bacteria such as Listera monocytogenes and Escherichia coli. It is due to the coordination of the diketone electron of Cur with diamagnetic and paramagnetic metal ions that influenced the antioxidant and antibacterial properties of Cur. Overall, this study proved that it was possible to use Cur in the form of Cur-Zn(II) complex as an antioxidant filler and Cur-Cu(II) complex as an antibacterial filler for active food packaging applications.

Ag–thiolate interactions to enable an ultrasensitive and stretchable MXene strain sensor with high temporospatial resolution

High-sensitivity strain sensing elements with a wide strain range, fast response, high stability, and small sensing areas are desirable for constructing strain sensor arrays with high temporospatial resolution. However, current strain sensors rely on crack-based conductive materials having an inherent tradeoff between their sensing area and performance. Here, we present a molecular-level crack modulation strategy in which we use layer-by-layer assembly to introduce strong, dynamic, and reversible coordination bonds in an MXene and silver nanowire-matrixed conductive film. We use this approach to fabricate a crack-based stretchable strain sensor with a very small sensing area (0.25 mm2). It also exhibits an ultrawide working strain range (0.001–37%), high sensitivity (gauge factor ~500 at 0.001% and >150,000 at 35%), fast response time, low hysteresis, and excellent long-term stability. Based on this high-performance sensing element and facile assembly process, a stretchable strain sensor array with a device density of 100 sensors per cm2 is realized. We demonstrate the practical use of the high-density strain sensor array as a multichannel pulse sensing system for monitoring pulses in terms of their spatiotemporal resolution.

Supramolecular Complexation Reinforced Polymer Frustrated Packing: Controllable Dual Porosity for Improved Permselectivity of Coordination Nanocage Mixed Matrix Membranes.

The developments of mixed matrix membranes (MMMs) are severely hindered by the complex inter-phase interaction and the resulting poor utilization of inorganics' microporosity. Herein, a dual porosity framework is constructed in MMMs to enhance the accessibility of inorganics' microporosity to external gas molecules for the effective application of microporosity for gas separation. Nanocomposite organogels are first prepared from the supramolecular complexation of rigid polymers and 2nm microporous coordination nanocages (CNCs). The network structures can be maintained with microporous features after solvent removal originated from the rigid nature of polymers, and the strong coordination and hydrogen bond between the two components. Moreover, the strong supramolecular attraction reinforces the frustrated packing of the rigid polymers on CNC surface, leading to polymer networks' extrinsic pores and the interconnection of CNCs' micro-cavities for the fast gas transportation. The gas permeabilities of the MMMs are 869 times for H2 and 1099 times for CO2 higher than those of pure polymers. The open metal sites from nanocage also contribute to the enhanced gas selectivity and the overall performance surpasses 2008 H2/CO2 Robeson upper bound. The supramolecular complexation reinforced packing frustration strategy offers a simple and practical solution to achieve improved gas permselectivity in MMMs.

Functionalized-MXene-based imprinted MOFs composite membranes for the selective separation of ribavirin

The evident decrease for membrane-treated performance in response to multi-component mixture greatly limited its application. Here, we prepared blended nanomolecularly imprinted composite fiber membranes (CXPM-MIMs) with in situ growth of imprinted MOFs on carboxyl functionalized MXene. Through the carboxylate-assisted coordination pathway, a chelation site is provided by the carboxylate-modified MXene to coordinate with NH2-UiO-66, creating a tightly linked NH2-UiO-66/carboxylate-functionalized MXene heterostructure. The key role of the modified carboxyl group can be identified so that it can help to create a strong coordination bond between the two materials. Conventional MOFs typically lack selectivity and specificity. Here, we present a molecularly imprinted nanocomposite MOFs membrane material that exhibits selective adsorption and molecular separation capabilities. Imprinted UiO-66 (Ce) based on diamino-terephthalic acid was synthesized with water as the only solvent without adding any regulator or additive. By adding ribavirin molecules to multicomponent MOFs using a molecular imprinting technique and carrying out adsorption tests (isothermal and kinetic) as well as selectivity testing, we were able to demonstrate this adsorption-separation mechanism. The valuable testing outcomes shown that the as-prepared CXPM-MIMs performed excellently in terms of pemselectivity for ribavirin (RBV) (permselectivity factor β = 4.89, 10.14, 9.23) in addition to exhibiting perfect specific adsorption ability (58.3 mg g−1). The strong permselectivity and particular identification capacity of CXPM-MIMs demonstrated their tremendous potential in the treatment of RBV contamination.

Engineering of uniform dispersed Ni nanoparticles supported on carbon nanosheets for reduction of Nitroarenes to Aminoarenes

Facile synthesis of uniform supported metal catalysts is of great significance yet remains challenging for sustainable catalysis. Herein, a nanopore confinement strategy is developed to efficiently anchor metal ions in suitably sized polymer nanopores via strong coordinate bonds and ensure successful fabrication of uniform carbon-supported metal nanoparticles. Specifically, Ni2+-coordinated polydopamine (PDA) mesoporous layer was coated on GO nanosheets for the confinement of the nickel atoms (GO@PDA-Ni-x, x means pore size of PDA layer), resulting Ni@C-x nanosheets catalysts with uniformly dispersed Ni nanoparticles after pyrolysis in H2/Ar atmosphere. Characterization methods including SEM, TEM, and XPS reveal the intrinsic formation mechanism and physicochemical details. In the catalytic reaction of NaBH4-mediated hydrogenation of 4-nitrophenol (4-NP), the obtained Ni/C-10 exhibits exceptional catalytic performance with a rapid rate constant (0.686 min−1), outperforming many previously reported metal catalysts. Moreover, the catalytic activity remains almost unchanged after being recycled five times, proving the prominent stability. This work opens up an innovative avenue for rational design and synthesis of supported catalysts with controllable size for broad catalytic applications.

Metal Complexes of Adenine Azo Ligand: Synthesis, Identification and Study some of their Applications

This scientific paper presents two novel lanthanide metal complexes [Sm (III) and Ce (IV)] synthesized through a series of reactions involving organic ligand 8-[3-(pyrazoyl)azo]adenine (PAA). Ligand (PAA) and their complexes were characterized using various analytical techniques, including C.H.N.S elemental analysis, magnetic measurement, X-ray diffraction, thermal analysis, SEM, (TGA) UV-Vis spectroscopy, FT-IR spectroscopy, and HNMR analysis. These techniques were employed to support the mode of binding and geometrical structure for ligand (PAA) and its Lanthanide (Ln) complexes. The FTIR and HNMR spectral results showed that (PAA) acts as neutral N,N-bidentate with [Sm (III) and Ce (IV)]. The geometric shape of the synthesized Ln-complexes is octahedral. Also, TGA was used to investigate the thermal behavior of ligand and its complex. The results showed that the ligand dissociated in three steps, while the complex dissociated in five steps. This indicates that the complex is more thermally stable than the ligand, likely due to the formation of strong coordination bonds between the ligand and the metal ions. These findings can contribute to the understanding of the thermal stability of metal complexes and inform the design of new metal-based materials with desirable properties. Finally, this paper examined the antibacterial, antifungal and anticancer activities of PAA and its complexes. The results indicated that all of these compounds exhibited significant activity against bacterial and fungal pathogens, as well as cancer cells.

The tightest self-assembled ruthenium metal-organic framework combined with proximity hybridization for ultrasensitive electrochemiluminescence analysis of paraquat.

Metal-organic frameworks (MOFs), as porous materials, have great potential for exploring high-performance electrochemiluminescence (ECL) probes. However, the constrained applicability of MOFs in the realm of ECL biosensing is primarily attributed to their inadequate water stability, which consequently impairs the overall ECL efficiency. Herein, we developed a competitive ECL biosensor based on a novel tightest structural ruthenium-based organic framework emitter combining the proximity hybridization-induced catalytic hairpin assembly (CHA) strategy and the quenching effect between the Ru-MOF and ferrocene for detecting paraquat (PQ). Through a simple hydrothermal synthesis strategy, ruthenium and 2,2'-bipyrimidine (bpm) are head-to-head self-assembled to obtain a novel tightest structural Ru-MOF. Due to the metal-ligand charge-transfer (MLCT) effect between ruthenium and the bpm ligand and the connectivity between the internal chromophore units, the Ru-MOF exhibits strong ECL emissions. Meanwhile, the coordination-driven Ru-MOF utilizes strong metal-organic coordination bonds as building blocks, which effectively solves the problem of serious leakage of chromophores caused by water solubility. The sensitive analysis of PQ is realized in the range of 1 pg/mL to 1 ng/mL with a detection limit of 0.352 pg/mL. The tightest structural Ru-MOF driven by the coordination of ruthenium and bridging ligands (2,2'-bipyrimidine, bpm) provides new horizons for exploring high-performance MOF-based ECL probes for quantitative analysis of biomarkers.

Fine optimized cation immobilization strategy for enhancing stability and efficiency of perovskite solar cells

The migration and volatilization of cations within organic–inorganic hybrid perovskite (OIPs) materials has been identified as a major issue for irreversibly degrading perovskite solar cells (PSCs), severely limiting their performance and impeding progress toward large-scale applications. To mitigate these problems, an adjustable cation immobilization strategy was proposed for the first time, in which a series of fluorobenzenesulfonamide (FBSA) molecules was introduced into perovskite precursor, a strong coordination bond was formed between the sulfonamide group with the octahedral imperfection caused by iodine vacancy, along with a hydrogen bond formed between the cation and F atom. As a result, the A-site cations were tightly immobilized in the octahedral of perovskite crystal lattice and the uncoordinated Pb2+ defects were effectively eliminated. Besides, the immobilization distance of cation was finely optimized by changing the substitution position of F atoms. Based on the cation-immobilized perovskite film, the efficiency of PSCs was significantly increased from 19.88 % to 22.30 %. Moreover, the unencapsulated PSCs exhibited impressive light and thermal stability, retaining 82 % of the initial efficiency after 720 h illumination at 1-sun, and maintaining nearly 80 % of the initial PCE after heating at 85 °C for 240 h. Thus, the present study offers a promising approach for advancing the commercialization of stable and high-efficiency perovskite solar cells.

3-(2-pyridyl)-5-(4-chlorophenyl)-1,2,4-triazine as a ligand: Synthesis of three lead(II) complexes, a spectroscopic and structural study using experimental and theoretical methods

Three new Pb(II) complexes of the ligand 3-(2-pyridyl)-5-(4-chlorophenyl)-1,2,4-triazine (pcpt) and different anionic co-ligands (1: bromide, 2: iodide and 3: isothiocyanate) were synthesized and characterized by elemental (CHN) analysis, FT-IR and 1H NMR spectroscopy and single crystal X-ray diffraction (SC-XRD). Considering only strong primary coordination bonds, the Pb(II) centres in complexes 1 and 2 are holodirectionally and in 3 hemidirectionally coordinated by the organic pcpt ligands due to stereochemical inactivity (1, 2) and activity (3) of the lone electron pair. The primary coordination sphere in 3 is sterically suitable for establishing interactions at longer distances, where the Pb centre acts as Lewis acid. Thus, all the Pb centers participate in Pb⋅⋅⋅Cl tetrel interactions, which together with secondary interactions of the ligands extend the structures into 1D supramolecular assemblies. A Hirshfeld surface inspection, along with the natural bond analysis (NBO), quantum theory of atoms in molecules (ATAIM), molecular electrostatistic potential (MEP) surface, and theoretical vibrational analysis at B3LYP/Def2-TZVP level of theory were conducted for the sake of further investigation of the non-covalent interactions in complexes 1–3. An enrichment ratio is also calculated for the chemical species to determine the tendency of their interactions in the crystal packing. The theoretical values obtained from the DFT at B3LYP/Def2-TZVP level of theory ensure that the expected consequences match the experimental findings. The QTAIM calculations allow the estimation of the strength of the primary and secondary/tetrel interactions and to propose the theoretical criteria based on the |VBCP|/GBCP, HBCP/ρBCP, and DI parameters for distinguishing the interactions. The MEP calculations confirmed the presence of a σ-hole in the proximity of the PbII centers.

Melt-quenched carboxylate metal–organic framework glasses

Although carboxylate-based frameworks are commonly used architectures in metal-organic frameworks (MOFs), liquid/glass MOFs have thus far mainly been obtained from azole- or weakly coordinating ligand-based frameworks. This is because strong coordination bonds of carboxylate ligands to metals block the thermal vitrification pathways of carboxylate-based MOFs. In this study, we present the example of carboxylate-based melt-quenched MOF glasses comprising Mg2+ or Mn2+ with an aliphatic carboxylate ligand, adipate. These MOFs have a low melting temperature (Tm) of 284 °C and 238 °C, respectively, compared to zeolitic-imidazolate framework (ZIF) glasses, and superior mechanical properties in terms of hardness and elastic modulus. The low Tm may be attributed to the flexibility and low symmetry of the aliphatic carboxylate ligand, which raises the entropy of fusion (ΔSfus), and the lack of crystal field stabilization energy on metal ions, reducing enthalpy of fusion (ΔHfus). This research will serve as a cornerstone for the integration of numerous carboxylate-based MOFs into MOF glasses.

Effect of chitosan coating on drug carrier capacity of metal organic framework MIL-100(Fe) contained cyclophosphamide.

In recent years, the field of biomedical engineering, particularly drug delivery, has seen significant advancements in the evaluation of various drug carriers. Metal-organic frameworks (MOFs), are porous materials with strong coordination bonds. They have emerged as a promising tool for enhancing the effectiveness of drug delivery. In this investigation, the effect of chitosan coating on cyclophosphamide loading of MIL-100(Fe) was studied in computational and experimental way. The chitosan-coated MIL-100(Fe) containing cyclophosphamide (MIL-100(Fe)/CS/CP) was characterized by SEM, FTIR, BET, DLS, and powder X-ray diffraction analysis. The drug loading and release process were quantified using UV-spectroscopy. In vivo-In vitro study was performed. The result of drug loading in chitosan-coated MIL-100(Fe) with a drug payload of 32% revealed a significant increase compared with the MIL-100(Fe) with a 26.41% payload. According to the DLS analysis the existence of chitosan increase MIL-100(Fe) particle size (381 to 463nm) and change the zeta potential from 18 to -17mV. The toxic effect of MIL-100(Fe)/CS/CP was determined on human breast cancer (MCF-7) cells. In vivo images and H&E analysis shows inhibition properties of MIL-100(Fe)/CS/CP on tumor cells. The amount of drug loading of MIL-100(Fe) particles and MIL-100(Fe)/CS was simulated using molecular dynamic software LAAMPS. MIL-100(Fe) was synthesized biofriendly at room pressure and temperature with an Iron (II) chloride source coated with chitosan (CS) a natural polysaccharide. Incorporating MIL-100(Fe) with this natural polymer enhanced the drug loading capacity of MIL-100(Fe) and controlled drug release.

An Investigation into the Stability Source of Collagen Fiber Modified Using Cr(III): An Adsorption Isotherm Study.

The enhanced hydrothermal stability of leather, imparted by little Cr(III), has traditionally been ascribed to strong coordinate bonds. However, this explanation falls short when considering that the heat-induced shrinking of collagen fiber is predominantly driven by rupturing weak H-bonds. This study explored the stability source via adsorption thermodynamics using collagen fiber as an adsorbent. Eleven isotherm models were fitted with the equilibrium dataset. Nine of these models aptly described Cr(III) adsorption based on the physical interpretations of model parameters and error functions. The adsorption equilibrium constants from six models could be transformed into dimensionless thermodynamic equilibrium constants. Based on the higher R2 of the van't Hoff equation, thermodynamic parameters (∆G°, ∆H°, ∆S°) from the Fritz-Shluender isotherm model revealed that the adsorption process typifies endothermic and spontaneous chemisorption, emphasizing entropy increase as the primary driver of Cr(III) bonding with collagen. Thus, the release of bound H2O from collagen is identified as the stability source of collagen fiber modified by Cr(III). This research not only clarifies the selection and applicability of the isotherm model in a specific aqueous system but also identifies entropy, rather than enthalpy, as the principal stability source of Cr-leather. These insights facilitate the development of novel methods to obtain stable collagen-based material.

Low thermal quenching of metal halide-based metal-organic framework phosphor for light-emitting diodes.

Phosphor-converted white light-emitting diodes (PC-WLEDs) have attracted considerable attention in solid-state lighting and display. However, urgent issues of thermal quenching and high cost remain formidable challenges. Herein, a novel metal-organic framework (MOF) phosphor [CdCl2(AD)] was facilely prepared using a mixture of CdCl2 and acridine (AD) under solvothermal conditions. It shows intensive green emission with a long lifetime of 31.88 ns and quantum yield of 65% while maintaining 95% and 84% of its initial emission intensity after remaining immersed in water for 60 days and being heated to 150 °C, respectively. The low thermal quenching of this MOF material is comparable to or can even exceed that of commercial inorganic phosphors. The combination of experiments and theoretical calculations reveals that the alternating arrangement of delocalized AD π-conjugated systems and CdCl2 inorganic chains through strong coordination bonds and π⋯π stacking interactions imparts the MOF phosphor with high thermal stability and optoelectronic performance. The successful fabrication of green and white LED devices by coating [CdCl2(AD)] and/or N630 red phosphor on a 365/460 nm commercial diode chip suggests a promising and potential alternative to commercial phosphors.

Surface co-modification enabling efficient and spectrally stable mixed-halide blue light-emitting diodes

Collaborative optimization of strong coordination and hydrogen bonds is employed to impede phase separation and enhance photoluminescence for mixed-halide QDs.

Cu(II) inhibited the transport of tetracycline in porous media: role of complexation.

Tetracycline (TC) and Cu(II) coexist commonly in various waters, which may infiltrate into the subterranean environment through runoff and leaching, resulting in substantial ecological risks. However, the underlying mechanisms why Cu(II) affects the transport of TC in porous media remain to be further explored and supported by more evidence, especially the role of complexation. In this study, the transport of TC with coexisting Cu(II) was comprehensively explored with column experiments and density functional theory (DFT) calculation. At natural environmental concentrations, Cu(II) significantly inhibited the transport of TC in the quartz sand column. Cu(II) augmented the retention of TC in the column mainly via electrostatic force and complexation. The interaction between TC and TC-Cu complexes on the surface of SiO2 was investigated with first-principles calculations for the first time. There were strong van der Waals forces and coordination bonds on the surface of complexes and SiO2, leading to higher adsorption energy than that of TC and inhibiting its penetration. This study offers novel insights and theoretical framework for the transport of antibiotics in the presence of metal ions to better understand the fate of antibiotics in nature.

Adsorption and Kinetic Studies of Nickel(II) Ions onto Vermiculite based Ionite

Using vermiculite based ionite, the absorption efficiencies of Ni2+ ions from synthetic solutions were investigated. The effects of pH and initial concentration of Ni2+ ions their absorption capacity were investigated to optimize process conditions using pseudo-first and pseudo-second-order. The results obtained from the sorption of Ni2+ ions on vermiculite based ionite show the kinetic characteristics close to the pseudo-second order. The high Ni2+ ions sorption is attributed due to the the complexation of metal ions with −NH2 groups present in the absorbent, which results in the strong coordination bonds.

In Ukrainian

Thermal destruction of composites of ureaformaldehyde (UPR) and polyester resins (PER) with silicon dioxide nanoparticles having a specific surface area of 280 m2/g, titanium dioxide and titanosilicate with a specific surface area of 40 and 48 m2/g, respectively, when a filler content is no more than 5.0 wt% have been studied. The investigations were performed using The thermally programmed mass spectrometry method with registration of the masses of desorbed atomic fragments in the 10 ‒ 200 m/z range. It was established that during the main polymer mass destruction at 150 ‒ 350 oC, along with low temperature decomposition products, anomalously high thermal resistance of a number of atomic fragments of polymer chains and cross-links are recorded. The atomic composition of destruction fragments and their desorption temperature in the range 400 ‒ 700 oС were determined. It was established that in composites of ureaformaldehyde resin with SiO2 and TiO2 nanoparticles the high temperature resistance of fragments with m/z 27 exhibits due to the formation of strong bonds among the Si and Ti surface sites and the nitrogen atoms of the polymer. Such thermal stability is not realized in resin loading with (Si/Ti)O2 nanoparticles. In composites of polyester resin with silica a high-temperature destruction of oxygen atoms from polyester chains realizes at temperatures of 290 ‒ 400 oC and a low-intensity wide destruction band takes place in the temperature range 400 ‒ 700 oC. In addition, in the temperature range of 400-700 oC cross-links are destroyed with the release of benzene rings and styrene molecules. It was established that anomalously high-temperature desorption is typical for atomic fragments of the polymer structure attached to surface Si and Ti sites through nitrogen or carbon atoms from the polymer structure. Thus, in UPR composites with silicon and titanium oxides, strong chemical nitride bonds of the form Si-N≡C-H and Ti-N≡C-H are formed, which demonstrate anomalously high heat resistance. It is shown that in composites of polyester resin with silicon dioxide nanoparticles, the high-temperature destruction of fragments is due to their desorption from the surface of silicon dioxide particles when breaking their bonds with silicon atoms. Thus, polymer matrices have been determined, in which atomic fragments of the macromolecule, binding to the surface centers of fillers, significantly weaken the thermal destruction of composites due to the formation of strong chemical and coordination bonds.

Enhanced Mechanical Strength of Metal Ion-Doped MXene-Based Double-Network Hydrogels for Highly Sensitive and Durable Flexible Sensors.

Development of conductive hydrogels with high sensitivity and excellent mechanical properties remains a challenge for constructing flexible sensor devices. Herein, a universal strategy is presented for enhancing the mechanical strength of Mxene-based double-network hydrogels through metal ion coordination effects. Polyacrylamide (PAM)/sodium alginate (SA)/Mxene double-network (PSM-DN) hydrogels were prepared by metal ion impregnation of PAM/SA/Mxene (PSM) hydrogels. High electrical conductivity is achieved due to MXene nanosheets, while the strong coordination bond between metal ions and SA constructs a second network that increases the mechanical strength of the hydrogel by an order of magnitude. Mechanical tests demonstrated that the elastic modulus of hydrogels matches that of human tissues. Hence, they can be used as a highly sensitive electronic skin sensor to recognize the movement of different joints in humans and also as a pressure sensing interface to recognize characters for anticounterfeiting and information transfer. This work can promote the practical application of conductive hydrogels in high-tech fields, such as flexible electronic skin and interface interaction.