Thiol-ene Click Reaction Research Articles

Click dechlorination of halogen-containing hazardous plastics towards recyclable vitrimers.

Amid the ongoing Global Plastics Treaty, high-quality circulation of halogen-containing plastics in an environmentally sound manner is a globally pressing issue. Current chemical dechlorination methods are limited by their inability to recycle PVC at the long-chain carbon level and the persistence of eco-toxic organochlorine byproducts. Herein, we propose a click dechlorination strategy for transforming waste PVC into valuable vitrimers via a one-step cascade thiol-ene click reaction and dynamic polymerization. Thermal activation of C-Cl bonds initiates β-elimination dechlorination, while disulfide bonds synchronously undergo homolytic cleavage, generating sulfur-centered radicals that drive precise sulfur-chlorine substitution and the formation of disulfide dynamic networks. This strategy achieves nearly complete chlorine extraction (93.88%) and produces vitrimers with tailorable mechanical and reprocessing properties, spanning from soft elastomers with 784% elongation to rigid plastics with a yield strength of 34 MPa. The significant advantage of this strategy is backbone protective precise dechlorination, enabling ecosystem toxicity reduced by 99.51% compared with widely adopted pyrolysis methods. This work introduces a sustainable pathway for upcycling PVC into valuable materials, marking significant progress in chlorinated plastic recycling.

Solar light driven photochromic membranes with viologen additives in PVDF/PVP matrix

This study explores the synthesis and characterization of photochromic Polyvinylidenefluoride/Polyvinylpyrrolidone (PVDF/PVP)-based membranes, prepared through an in situ thiol-ene click reaction by incorporating viologen derivatives with different counter ions. Viologens are well-known for their light-sensitive properties and ability to change color, making them useful in various optoelectronic applications. The membranes developed in this study exhibit significant improvements in their interactions with light as a result of improved morphology and enhanced ionic conductivity (≈4 × 10−4 S cm–1) with higher porosity (Ra: 11.26–33.76 nm) compared to conventionally prepared membranes. These membranes show the ability to block almost all ultraviolet (UV) and a 90% of visible light after irradiation. Thanks to these properties, the membranes undergo visible color changes when exposed to sunlight, making them suitable for photochromic and thermochromic applications. The findings of this study could contribute to the development of innovative coating materials that enhance energy efficiency, potentially being applied to buildings, automotive windows, and other surfaces.

Preparation and Application of Weak Cation Exchange Resin Based on Thiol Click Reaction.

Using poly(styrene-divinylbenzene) microspheres as stationary phase matrix and mercaptosuccinic acid as a modifier, a new weak cation exchange resin was synthesized by thiol click reaction. The conditions for thiol-chlorine click reaction and thiol-alkene click reaction were optimized. The surface morphology and chemical composition of the modified microspheres were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and an elemental analyzer. The stationary phase can achieve the separation of six common cations within 25min. A homemade weak cation chromatographic column was used to determine the impurities of Na+ and K+ and the content of tetramethylammonium ions in tetramethylammonium hydroxide samples. The method showed a good linear correlation in the range of 0.1-500.0mg/L with correlation coefficients of 0.9998-0.9999, and the limits of detection (signal-to-noise ratio ≥ 3) were 0.01-0.20mg/L. The intra-day relative standard deviations (RSDs) were in the range of 1.1%-4.4%, and the inter-day RSDs were in the range of 0.8%-14.8%. The spiked recoveries were in the range of 91.92%-119.86%. The results showed that the prepared stationary phase exhibited effective separation ability and good reproducibility, which was suitable for the analysis of the impurities of Na+, K+, and the content of tetramethylammonium in the tetramethylammonium reagents.

Designing High-Performance Green Tire Treads by Reinforcing the Styrene-Butadiene Rubber/Silica Interface with Chain Difunctionalization

For green tires, monofunctionalization of rubber has been extensively studied to enhance the interface between rubber and silica. However, the effect of chain difunctionalization has not been reported. In this work, the difunctionalized styrene-butadiene rubber (SBR-DF) was first prepared by grafting small molecules with different functional groups (3-mercaptopropionic acid, 3-mercaptoethanol, and mercaptosilane) to end-group functionalized SBR through thiol-ene click reaction. Then, the molecular dynamics simulation was adopted to calculate the interaction energy between SBR-DF and silica. The results showed that the chain difunctionalization can significantly increase the interfacial interaction energy between them, which was further validated by using RPA and SEM. Moreover, the introduced siloxane groups in the rubber chain can greatly improve the interfacial interaction energy by more than 20%, which can achieve the uniform dispersion of silica. As a result, the SBR-DF/Silica composites showed the excellent dynamic mechanical properties, such as high wet slip resistance (21% increase), low rolling resistance (23% reduction) and high wear resistance (20% reduction). As a result, the energy consumption of SBR-DF/Silica composites was reduced, which endowed green tires with excellent safety. In summary, this work provides a new and effective strategy for manufacturing the energy-saving, green and safe design of “green tires”.

Proportionally controlled dual-chiral covalent organic frameworks via thiol-ene click reaction for efficient enantioseparation

Developing a universally applicable and commercially hopeful chiral material is a significant challenge for the separation and analysis field. In this study, innovative dual-chiral CCOFs ([SH-β-CD-NALC]x-COFs) modified with 6-deoxy-6-mercapto-β-cyclodextrin (SH-β-CD) and N-acetyl-l-cysteine (NALC) are presented. These CCOFs were synthesized using a single, one-step bottom-up approach at room temperature, specifically designed for enantiomer recognition and separation. We investigated the effect of varying ratios of multiple chiral selectors in CCOFs on chiral recognition abilities through adsorption experiments for the first time. The precisely engineered [SH-β-CD-NALC]1/6-COF, with excellent stability, crystallinity, abundant chiral sites, and a greater specific surface area, was well suited as a chiral stationary phase (CSP) in various racemates separation. The results showed satisfactory resolution, column efficiency, stability, and reproducibility. In addition, mechanism studies have revealed that the dual-chiral COF can offer triple selectivity and achieve the effect where 1 + 1 is greater than 2. This work emphasized the advantages of dual-chiral COF in achieving racemic drug separation, providing a new approach for the development of high-performance chiral separation platforms in the future.

Gradient Functionalization of Poly(lactic acid)-Based Materials with Polylysine for Spatially Controlled Cell Adhesion.

The development of biomaterials with gradient surface modification capable of spatially controlled cell adhesion and migration is of great importance for tissue engineering and regeneration. In this study, we proposed a method for the covalent modification of PLA-based materials with a cationic polypeptide (polylysine, PLys) via a thiol-ene click reaction carried out under a light gradient. With this aim, PLA-based films were fabricated and modified with 2-aminoethyl methacrylate (AEMA) as a double bond source. The latter was introduced by reacting pre-formed and activated surface carboxyl groups with the amino group of AEMA. The success of the modification was confirmed by 1H NMR, Raman and X-ray photoelectron spectroscopy data. A further photoinduced thiol-ene click reaction in the presence of a photosensitive initiator as a radical source was further optimized using cysteine. For grafting of PLys via the thiol-ene click reaction, PLys with a terminal thiol group was synthesized by ring-opening polymerization using Cys(Acm) as an amine initiator. Deprotection of the polypeptide resulted in the formation of free thiol groups of Cys-PLys. Successful gradient grafting of Cys-PLys was evidenced by covalent staining with the fluorescent dye Cy3-NHS. In addition, PLys gradient-dependent adhesion and migration of HEK 293 cells on PLys-PLA-based surfaces was confirmed.

Multifunctional Polymer Synthesis via Sequential Postpolymerization Modification Using a Single Aldehyde Repeat Unit: Allylation and Orthogonal Esterification and Thiol-ene Reaction.

Herein, we present a highly efficient method for synthesizing multifunctional polymers. This method involves the sequential postpolymerization modification (PPM) of a highly reactive aldehyde polymer. We introduce an allylic alcohol functionality into the polymer backbone via Barbier-type allylation, a process facilitated by easy-to-handle indium(0) powder. This step enables the formation of orthogonal pendants, secondary alcohol, and terminal alkene, which can be further functionalized through esterification and thiol-ene click reactions. All of these processes are carried out under mild conditions, ensuring high efficiency and a wide range of functional groups. Our study underscores PPM's operational simplicity and versatility in developing advanced polymer materials and expanding the scope of multifunctional polymer design.

Sustainable synthesis and dual adsorption of methyl orange and cadmium ions using biogenic silica-based fibrous silica functionalized with crown ether ionic liquid

In pursuit of sustainable nanomaterial production, this study presents a novel biogenic fibrous silica sphere functionalized with a crown ether ionic liquid for advanced dual-adsorption of methyl orange and Cd(II) from aqueous solutions. Sorghum waste serves as the silica source in the adsorbent preparation process, ensuring an eco-friendly approach. The benzo-15-crown-5 ionic liquid is coupled to thiol-functionalized fibrous silica spheres through an efficient thiol-ene click reaction. Under constant conditions (temperature: 298 K, solution volume = 50 mL, adsorbent dosage = 5 mg, pH = 7, shaking speed = 200 rpm), the synthesized material demonstrates maximum adsorption capacities of 507.1 mg/g and 306.3 mg/g for methyl orange and Cd(II), respectively, according to the Langmuir model. Thermodynamic investigations reveal endothermic adsorption for methyl orange with an enthalpy change of −77.49 KJ mol−1, while exothermic adsorption is observed for Cd(II) with an enthalpy of +24.10 KJ mol−1. The entropy change of adsorption is −0.153 KJ mol−1 K−1 for methyl orange, indicating a more ordered state, and + 0.192 KJ mol−1 K−1 for Cd(II), suggesting increased disorder. The change in Gibbs free energy ranges from −32.66 to −29.60 KJ mol−1 for methyl orange and −32.29 to −35.99 KJ mol−1 for Cd(II), demonstrating that both adsorption processes are spontaneous. These results indicate that the adsorbent has potential as a dual-adsorption material for water remediation applications.

Polyacrylonitrile nanofibrous mat modified with cysteamine and ionic liquid as a recyclable and efficient adsorbent for selective removal of sulfonamides and Cu(II) from aqueous solution: Roles of multi-function adsorption

The combined contamination of heavy metals and antibiotics is a prevalent occurrence, yet the distinct chemical characteristics of these substances pose a significant obstacle to their simultaneous elimination. In this work, novel polyacrylonitrile nanofibrous mat (NFsM) modified with cysteamine and ionic liquid (IL@Cys@PAN NFsM) was developed using a cascade thiol-ene click reaction. The IL@Cys@PAN NFsM exhibits a rich array of functional groups and demonstrates strong binding affinity, fast mass transfer, and exceptional selectivity for sulfonamides (SAs) and Cu(II). The maximum adsorption capacities for SAs and Cu(II) in single-component systems were 122.3 and 97.4 mg/g respectively, according to the Langmuir isotherm model. The time dependent adsorption capacities followed a pseudo-second-order kinetic model, demonstrating a chemisorption-dominant process for each analyte. In binary pollutant systems, the co-occurrence of SAs and Cu(II) in water produced a competitive effect; however, the decrease in adsorption capacity was minimal. Through experimental analysis, FTIR characterization and density functional theory (DFT) studies, reasonable interactions of hydrogen-bond, electrostatic interactions, π-π stacking for SAs, and chelation effect for Cu(II) were proposed. Additionally, the reusability and recyclability of IL@Cys@PAN NFsM enhance its practicality for real-world applications. This paper presents the first systematic study on the simultaneous adsorption of heavy metals and antibiotics using NFsM, offering a novel perspective on the design of custom adsorbents capable of efficiently removing multiple contaminants with diverse characteristics while balancing eco-friendliness, excellent adsorption performance, and impressive recyclability for wastewater remediation.

A Scalable Method to Fabricate 2D Hydrogel Substrates for Mechanobiology Studies with Independent Tuning of Adhesiveness and Stiffness.

Mechanical signals from the extracellular matrix are crucial in guiding cellular behavior. Two-dimensional hydrogel substrates for cell cultures serve as exceptional tools for mechanobiology studies because they mimic the biomechanical and adhesive characteristics of natural environments. However, the interdisciplinary knowledge required to synthetize and manipulate these biomaterials typically restricts their widespread use in biological laboratories, which may not have the material science expertise or specialized instrumentation. To address this, we propose a scalable method that requires minimal setup to produce 2D hydrogel substrates with independent modulation of the rigidity and adhesiveness within the range typical of natural tissues. In this method, norbornene-terminated 8-arm polyethylene glycol is stoichiometrically functionalized with RGD peptides and crosslinked with a di-cysteine terminated peptide via a thiol-ene click reaction. Since the synthesis process significantly influences the final properties of the hydrogels, we provide a detailed description of the chemical procedure to ensure reproducibility and high throughput results. We demonstrate examples of cell mechanosignaling by monitoring the activation state of the mechanoeffector proteins YAP/TAZ. This method effectively dissects the influence of biophysical and adhesive cues on cell behavior. We believe that our procedure will be easily adopted by other cell biology laboratories, improving its accessibility and practical application.

Fabrication of clickable bamboo-sourced cellulose nanofibrils for diverse surface modifications: Hydrophobicity and fluorescence functionalities

Surface functionalization of cellulose nanofibrils (CNF) is crucial for expanding their practical application. However, most functionalization processes are complicated and laborious. Herein, this work presents a facile surface engineering strategy to create a range of functionalized CNF via thiol-ene click reaction. Initially, clickable CNF was produced by grafting a compound with both carboxylate- and norbornene groups onto bamboo cellulose via norbornene-dicarboxylic anhydride esterification followed by homogenization. The introduction of negatively charged carboxylates facilitated nanofibrillation, resulting in CNF with a diameter of 3 nm and an aspect ratio of up to 600. The introduction of norbornenes enabled diverse functionalization of CNF through click reaction. Subsequently, hexadecanethiol successfully clicked with norbornene-grafting CNF, enhancing its hydrophobicity and dispersion in organic solvents. 7-mercapto-4-methyl coumarin was also able to click with norbornene-grafting CNF, yielding fluorescence-labeled CNF while maintaining excellent aqueous dispersibility. The fluorescence-labeled CNF was demonstrated to be utilized as an eco-friendly sensor for the detection of Fe3+ ions. Additionally, it could be converted into fluorescent films or intelligent inks suitable for anti-counterfeiting purposes. This study demonstrates that the proposed surface engineering strategy provides an effective approach for producing clickable CNF and fabricating cellulosic materials with diverse functionalities that meet the demands of various applications.

Preparation of chitosan-based macromolecular antioxidant with high-efficiency free radical scavenging ability to improve the antioxidative properties of styrene-butadiene rubber/silica composites

To address the disadvantages of traditional rubber antioxidants with low molecular weight such as easy migration, poor extraction resistance, low thermal stability and antioxidant efficiency, in this work, we first prepared an antioxidant containing primary and secondary antioxidant groups (MC-MPA) through thiol-ene click reaction between N-(4-aminophenyl)maleimide (MC) and 3-mercaptopropionic acid (MPA). Then, we synthesized a chitosan-based macromolecular antioxidant with long-chain alkene, aromatic secondary amine, and thioether groups (COS-UC-MC-MPA) by sequentially grafting functional compounds 10-undecanonyl chloride (UC) and antioxidant MC-MPA onto natural macromolecular polymer chitosan (COS). The free radical scavenging ability of COS-UC-MC-MPA was assessed by using 2,2-Diphenyl-1-picrylhydrazyl (DPPH), and the results demonstrated that COS-OC-MC-MPA has high scavenging rate of 76.5 % for DPPH free radicals after 1 min of contact with DPPH dimethyl sulfoxide solution, showing excellent free radical scavenging ability. In addition, the results of accelerated thermo-oxidative aging test, thermogravimetric (TG) test, kinetic analysis of thermal-oxidative degradation, extraction resistance test, and volatilization resistance test indicated that COS-UC-MC-MPA with superior migration resistance and volatilization resistance could effectively enhance the antioxidative properties, thermal stability and thermal-oxidative stability of rubber composites. Moreover, the results of rubber processibility analysis (RPA) test and scanning electron microscopy (SEM) implied that the addition of COS-UC-MC-MPA is also conductive to improving the dispersibility of silica in rubber matrix. This study supplies a new perspective for the preparation of environmentally friendly and highly efficient macromolecular antioxidants for rubber composites.

Rational design of a room‐temperature curing method, based on the epoxy–thiol click reaction, for UV‐curable hard coatings with ultrahigh strength and adhesion

AbstractIn recent years, there has been a growing demand for UV‐curable hard coatings because they offer several advantages, for example, lower energy consumption and the absence of volatile organic compound emissions. Anionic UV curing with photobase generators (PBGs), such as epoxy–thiol cross‐linking, enables curing under ambient conditions. However, designing a room‐temperature photoanionic curing system for epoxy–thiols remains challenging due to the complex effects of resin combinations on the cured products, thus making it difficult to prepare films with high hardness. Herein, we present a controlled reaction design for an anionic UV‐curing system by combining the chemical structures of epoxy resins and multifunctional thiols. The anionic UV‐curing system using PBGs that generate organic superbases demonstrated UV‐delayed curability, as evidenced by FT‐IR and photorheological analyses. To achieve high hardness, it was necessary to create the thiols with ultrarigid structures; epoxy resins with a bisphenol F structure were optimal for reacting with thiols for ultrarigid structures. This combination afforded an indentation hardness of 262 MPa with an epoxy conversion rate of 77% even at room temperature.

Surface Passivation of Norland Optical Adhesive Improves the Guiding Efficiency of Gliding Microtubules in Microfluidic Devices.

The microtubule-kinesin biomolecular motor system, which is vital for cellular function, holds significant promise for nanotechnological applications. In vitro gliding assays have demonstrated the ability to transport microcargo by propelling microtubules across kinesin-coated surfaces. However, the uncontrolled directional motion of microtubules has posed significant challenges, limiting the system's application for precise cargo delivery. Microfluidic devices provide a means to direct microtubule movement through their geometric features. Norland Optical Adhesive (NOA) is valued for its mold-free application in microfluidic device fabrication; however, microtubules often climb up channel walls, limiting controlled movement. In this study, a surface passivation method for NOA is introduced, using polyethylene glycol via a thiol-ene click reaction. This technique significantly improved the directional control and concentration of microtubules within NOA microchannels. This approach presents new possibilities for the precise application of biomolecular motors in nanotechnology, enabling advancements in the design of microfluidic systems for complex biomolecular manipulations.

Synthesis of vinyl functionalized polyurethane acrylate oligomers and their photopolymerization via thiol-ene click reaction

Functional polyvinylethylene glycols (PVEGs) with different central structures were synthesized by Pd/B synergistic catalysts and reacted with isophorone diisocyanate (IPDI) and 2-hydroxyethyl methacrylate(HEMA) to prepared pendent vinyl-functional polyurethane acrylates (VFPUAs). The photopolymerization of the obtained VFPUAs with pentaerythritol tetra(3-mercaptopropionate) (PETMP) in the presence of a photoinitiator proceeded smoothly via thiol-ene photo-click reaction to give a series of crosslinked materials by the variation of the chemical structure of VFPUAs and a ratio of thiols and enes. The curing behavior was studied by FT-IR and the properties of crosslinked materials were characterized by the test of gel content, swelling ratio and water absorption. The dynamic mechanical properties, mechanical properties, thermogravimetry and surface properties of the crosslinked materials were investigated and the performance of coating for the crosslinked film materials was also characterized. The crosslinked film materials can be further functionalized by post-crosslinking modification through thiol-ene photo-click reaction.

Synthesis of phosphorus, sulfur and silicon-containing flame retardant via thiol-ene click reaction and its use for durable finishing of cotton fabric

The article presents a very simple method of synthesis and application of a halogen and formaldehyde free, P, S and Si-containing flame retardant for the durable finishing of cotton fabric. The compound was obtained as a result of the thiol-ene click reaction. The compound was designed to have two functional groups: an alkoxysilyl group for cross-linking and binding to the cotton fabric, and a phosphate group to provide flame retardant properties. The flame retardant was applied to cotton fabric using the sol–gel method. According to the pyrolysis-combustion flow calorimetry (PCFC) technique, the use of the obtained silane for cotton treatment can reduce heat release rate (HRR) to almost 75% compared to the raw fabric. FT-IR analyses and SEM images indicate that impregnated cotton samples were covered with a layer of silanes. The SEM–EDS analysis confirmed successful modification of cotton fabrics. After 10 cycles of washing it was found that the created coatings are resistant to washing and retain their flame retardant properties.

Rapid preparation of injectable dual-network hydrogels for biomedical applications using UV-triggered sulfhydryl click reactions

The use of hydrogels to mimic natural cartilage implantation can effectively solve the current problems of insufficient cartilage donors and low rate of injury healing. In particular, injectable hydrogels are less invasive in clinical applications and better able to fill uneven injury surfaces. Here, we prepared NorCS and CS-SH by modifying chitosan with 5-norbornene-2-carboxylic acid and N-Acetyl-L-cysteine, respectively. Dual-network hydrogels were prepared by using UV-triggered thiol-ene click reaction between NorCS and CS-SH and the metal coordination between SA and Ca2+. The prepared hydrogels can be cross-linked quickly and exhibit excellent degradability, self-healing and injectable properties. At the same time, the hydrogel also showed good cytocompatibility and could significantly restore the motor function of mice. This study provides an effective strategy for preparing injectable hydrogels capable of rapid cross-linking.

Facile synthesis of a new chiral polyimine macrocycle and its application for enantioseparation in high-performance liquid chromatography

Macrocyclic compounds such as crown ethers and cyclodextrins play an important role in the field of chromatography and show excellent separation performance. The design of simple and convenient methods for the efficient synthesis of novel chiral macrocycles for chromatographic separation is of great significance. In this work, a novel chiral polyimine macrocycle (PIMC) was designed and synthesized by the simply one-step reaction of 2,6-diformyl-4-tert-butylphenol with (S)-(-)-1,2-propanediamine. Then, it was bonded onto silica by the thiol-ene click reaction to construct a new chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC). The chiral separation performance of the proposed CSP was examined by separating various racemates in the normal-phase (NP) and reversed-phase (RP) HPLC. In total, twelve and nine racemates, including ethers, esters, amines, alcohols, organic acids, ketones, and epoxides, were separated to varying degrees via NP-HPLC and RP-HPLC, respectively, Moreover, the CSP offered good chiral separation complementarity to Chiralcel OD-H and Chiralpak AD-H columns for resolution of these test racemates, and it can separate several racemic compounds that either cannot be separated or cannot be separated well be separated by the two commercially available columns. After the column was used for hundreds of injections, the relative standard deviations of the retention time and resolution were below 0.56 % and 0.45 %, respectively, showing the good reproducibility and stability of the CSP. This study provides a simple and convenient approach to synthesize a novel chiral macrocycle and CSP and also indicates the broad application prospects of such chiral PIMCs in HPLC chiral separation.

A fluorescent turn-on nanosensor for selective detection of L-morphine using D-cysteine-functionalized graphene quantum dots

Here, L- and D-cysteine-functionalized graphene quantum dots (L-/D-cys-GQDs) were designed with the aim of obtaining a selective fluorescent nanosensor to detect L-morphine. Citric acid was pyrolyzed to synthesize the GQDs, which were then functionalized with chiral L- and D-cys species using a thiol-ene click reaction between sulfur group of cysteine species and CC double bonds of GQDs. Energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopies (XPS) provides elemental analysis data which approved the presence of sulfur and nitrogen elements of L- and D-cysteine species on the surface of GQDs. Transmission electron microscopy (TEM) showed that the particle size of the modified GQDs ranges from 2 to 4.2 nm. The results of fluorescence spectroscopy showed that upon functionalization of GQDs with L-/D-cys the fluorescence intensity decreases as a result of Forster resonance energy transfer (FRET) mechanism. Interestingly, in the presence of L-morphine, the fluorescence intensity of D-cys-GQDs was selectively turned on as the FRET mechanism is ceased between the cysteine species and GQDs. Additional tests demonstrated that this nanosensor cannot interact with other drugs like methamphetamine or ibuprofen. As a result, it can serve as a cheap and precise nanosensor for identifying low quantities of L-morphine.

Efficient Synthesis of Metastable Cyclodextrin-Based Polyrotaxanes with Tunable Threading Ratios.

Cyclodextrin-based polyrotaxanes (CD-PRs) are gaining attention for their dynamic sliding rings along the polymer axis, enabling various applications in molecular shuttles, drug delivery, and durable polymers with slidable cross-links. However, the conventional synthesis of CD-PRs with tunable threading ratios is typically laborious, time-consuming, and complicated, which limits their scalability and cost-effectiveness. Herein, we highlight the great potential of planetary centrifugal mixing, a process that significantly accelerates and simplifies the initial synthesis of polypseudorotaxanes (PPRs), followed by a thiol-ene click reaction as an efficient end-capping reaction for the synthesis of PRs. Notably, PRs synthesized with glutathione (GSH) as the end-capping reagent are in a metastable state, where GSH act as a molecular bumper that significantly prevent de-threading of α-CD rings at room temperature. Moreover, the rate of ring de-threading can be precisely controlled by heating, enabling the preparation of metastable PRs with tunable threading ratios over a wide range. The developed strategy is of great significance to the efficient synthesis of CD-PRs, thus marking a significant step towards their practical application in advanced functional materials and devices.