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This paper describes the syntheses of four types of nitrile N-oxides (NOs) and studies on the thermal isomerization of NOs to isocyanates (Isocs). It is found that a bulky electron-withdrawing subs...

Polymeric quaterthiophenes containing optically active

The first synthesis of polyrotaxanes consisting of polyester axles and α-cyclodextrin (α-CD) wheels was achieved by the catalyst-free click end-capping reaction of polypseudorotaxanes using nitrile N-oxide. The polypseudorotaxanes contain acrylate-functionalized polyesters that are obtained by the living ring-opening polymerization of lactones. The yield and coverage ratio of polyrotaxanes are highly dependent on the reaction time, molecular weight of the polyester, polyester structure, and solvent used. From the thermal properties of the resulting polyrotaxanes, it was found that coverage with α-CDs efficiently suppresses the crystallization of the polyester main chain.

A bolaamphiphile contains a hydrophobic skeleton and two water-soluble groups on the both ends. Bolaamphiphile forms thermally stable associates in water under lower concentration than those of typical mono-headed amphiphiles, indicating the potential usefulness of bolaamphiphile as the component of nano-materials. However, the structural diversity of bolaamphiphiles is limited at this moment. Herein, we show the bolaamphiphilic properties of naturally occurring quercetin glycosides. In addition to natural flavonoids, quercetin (Que) and isoquercitrin (IQ), we have prepared quercetin polyglycoside (QP) via one-pot grafting polymerization using sugar-based cyclic sulfite as a monomer, which plays a crucial role to elucidate the effects of sugar chain length on the micellization. The micellization behaviors of QP are systematically investigated through the comparison with those of Que and IQ. The polyphenolic structures of quercetin derivatives exhibit unique pH-dependency of critical micelle concentration (CMC). While Que hardly forms micelles in pH 10.0 aqueous medium, the solutions of IQ and QP form micelles in the same medium, indicating that the sugar chain would endow the micelles with pH-tolerance. The effects of sugar chain length on the micellization behaviors are discussed through the time-course of UV-vis spectra and the profiles of dynamic light scattering (DLS) analyses. The morphology of the micelles bearing QP is observed by transmission electron microscopy (TEM), suggesting the formation of bolaamphiphile-specific helical ribbon-like micelles. It is indicated that the polysaccharide chains integrated on the surface of micelle would serve as a steric protecting group to afford kinetically stable micelles.

Polysaccharide is a naturally abundant material, which is regarded as an indispensable scaffold for a structural material. The properties of polysaccharides are dependent not only on the structure of repeating sugar unit but also the glycosidic position between the repeating units. Herein, we report the development of polysaccharide-based self-standing film consisting of naturally occurring (1 → 2)-glucopyranan skeleton. The self-standing film of (1 → 2)-glucopyranan derivative with hexyl carbamate groups

A series of alternating peptides with glycine-N-substituted valine dipeptide repeating units were synthesised. The N-substitution included methyl, ethyl, n-propyl, and hydroxyl groups. The performa...

α-Galactosyl ceramide (GalCer) is an anticancer glycolipid consisting of d-galactose and phytosphingosine-based ceramide. Although the amphiphilic structure of GalCer is expected to form self-associates in water, the self-assembly behaviors of GalCer and its derivatives have not been systematically investigated at this moment in spite of its great importance. The evaluation of morphologies and properties of the associates should open new insights into glycolipid chemistry such as the application of GalCer derivatives to a nanocarrier and the elucidation of the detailed pharmacological mechanism of GalCer. Herein, we show the synthesis of the aglycon fragment (Aglycon) of GalCer and the self-assembly behaviors of both GalCer and Aglycon in water. The critical aggregation concentrations of Aglycon and GalCer were determined using UV-vis spectral measurements at various concentrations. The transmission electron microscopy observations of the aqueous sample solutions indicated that the solution of GalCer includes vesicles, while that of Aglycon comprises giant micelles in the absence of vesicles. The vesicle formation in the solution of GalCer was also confirmed by Triton X-100-triggered dye-release experiments. To reveal the effects of glycon on the self-assembly behaviors in detail, we performed the measurements of dynamic light scattering, temperature-dependence of turbidity, differential scanning calorimetry, and wide-angle X-ray diffraction. The results clarify that the glycon moiety of GalCer has a significant role in the formation inhibition of second associates and the plasticization of the hydrophobe. This work will shed light on the other natural glycosides to evaluate the self-assembly behaviors for supramolecular and pharmacological applications in the near future.

In this study, we prepared silkworm silk films with fluorinated polypeptide coatings on their surface to achieve water-repellent silk materials. The silk films were smoothly and uniformly coated with the fluorinated polypeptides to give a transparent film. The contact angles of water droplets on the polypeptide-coated silk films were measured to investigate the ability of the films to resist water. The silk films coated with the fluorinated polypeptides exhibited higher contact angles compared to those of the uncoated silk film, indicating that the fluorinated polypeptides formed a hydrophobic surface on the silk film. The structure of the fluorinated polypeptides influenced the water-repellent ability, and the polypeptide containing both perfluoroalkyl chains and biphenyl groups imparted the highest water repellency. A biochemical oxygen demand (BOD) assay for the polypeptide-coated silk films in seawater revealed that the silk films showed high biodegradability in seawater even with the fluorinated polypeptide coating. The polypeptide-coated silk films provide not only high water repellency for practical use but also high biodegradability in marine environments.

We have prepared benzylated glucopyranans and evaluated the structural effects on the adhesion capacity. It was found that 97%-benzylated (1→2)-glucopyranan exhibited a unique shear-induced adhesion. The effects of structural factors on the adhesion behaviors are discussed through systematic adhesion tests, differential scanning calorimetry, theoretical models, and IR spectroscopy.

Quercetin polyglycoside as a new bolaamphiphile is prepared via a one-pot grafting polymerization technique using sugar-based cyclic sulfite. Micelles comprising quercetin polyglycoside exhibit special pH-effects, in which the polyglycoside moieties on the surface of the micelle serve as a steric protecting group to endow chemical stabilization.

This paper describes the experimental elucidation for the impact of polypeptide sequence on the solution structure and the thermo-responsivity, having considered the corresponding theoretical prediction using a binary pattern of hydrophobic and hydrophilic units. We prepare diblock, random, and alternating copolymers consisting of a stoichiometric amount of valine as a hydrophobic unit and glycine as a hydrophilic unit. Through the thermo-responsivity measurements of aqueous polymer solutions, it is found that the UV spectra of diblock copolypeptide exhibit a cloud point upon heating, which indicate that the polymer adopts a random coil structure at low temperature. On the other hand, the alternating peptide shows an upper critical solution temperature (UCST) behavior indicating a globule-to-coil transition upon heating. The opposite behavior of alternating peptide to that of diblock copolypeptide is found to be dependent on not the chirality of repeating units but the alternating binary pattern of hydrophobic and hydrophilic units. The random copolypeptide exhibits not only coil-to-globule transition at low temperature but also globule-to-coil transition at high temperature owing to the presence of both segregated and alternating polymer sequences in the polymer. The thermo-responsive structures of the polymers in an aqueous media are also discussed by determining the thermodynamic parameters for the transitions.

The synthesis of biocompatible nanomaterials from synthetic organic molecules, as well as the spin state switching of spin crossover complexes, are presently of interest. However, in the case of la...

The development of new peptide-based glues has been strongly urged from the viewpoints of industrial applications and biomedical engineering. However, the large-scale synthesis of polypeptides with an ordered sequence is highly challenging, which strictly restricts materials resources for the research and development of polypeptides. In this work, the framework of adhesive alternating peptides has been designed to be glycine (Gly)-N-substituted valine (Val) as the dipeptide repeating sequence, considering the peptapeptide repeating sequence of viscoelastic natural elastin as a motif. The alternating peptides are prepared via three-component polymerization exploiting Ugi four-center three-component reaction as the elemental polymerization reaction. The adhesive strength (SAdh ) values of the polymers are evaluated by a shear adhesive test method using two glass plates. Alternating peptides with Gly-N-benzylated Val dipeptide repeating units exhibit the optimal adhesive properties such as much higher SAdh than that of conventional fibrin glue and a unique readhesion capability. It is indicated that the remarkably high SAdh would be attributed to the shear-induced structural change of single polymer chain, the slow relaxation of extended structure, and the weak interchain interactions. Due to the favorable adhesive properties of alternating peptides, these adhesives may be highly suitable for real-world applications.

A bolaamphiphile is a special member of amphiphilic molecules, which contains a hydrophobic skeleton and two water-soluble groups on both ends. Bolaamphiphiles form thermally stable associates in water under lower concentration than those of typical monoheaded amphiphiles, indicating the potential usefulness of bolaamphiphiles as the component of nanomaterials. However, the structural diversity of bolaamphiphiles is limited at this moment. We recently developed the synthesis of quercetin-3-O-polyglycoside (QP) as a new entry of bolaamphiphiles via a one-pot polymerization using sugar-based cyclic sulfite initiated by quercetin skeleton. Herein, we show the bolaamphiphilic properties of QP in detail. The micellization behaviors of QP are systematically investigated through comparison with those of quercetin (Que) and isoquercitrin (IQ) to evaluate the roles of glycone on the micellization of quercetin derivatives. The morphology of the micelles bearing QP is observed by cryo-transmission electron microscopy (cryo-TEM), suggesting the formation of bolaamphiphile-specific giant ribbon-like micelles in addition to spherical micelles. The thermoresponsive micellization behaviors are also discussed through the critical micelle concentration (CMC) values, the dynamic light scattering analyses at various temperatures, and thermal hysteresis of the micellizations. It is indicated that the polysaccharide chains integrated on the surface of micelles would serve as a steric protecting group to endow the micelles with kinetic stability. These results will shed light on natural glycoside skeletons to design a new class of micelles for advanced health applications in near future.

Saccharification of a glass surface has been performed using two grafting methods: grafting-from and grafting-onto, using a sugar-based cyclic sulfite as monomer. Central to the technique is a cati...

We developed 2,5-furanylene sulfide-containing polymers bearing different spacers as repeating units and evaluated the interactions between the furanylene sulfide units in the polymers. The treatment of 2,5-dichlorofuran derivatives with dithiolates at 200 °C promotes polycondensation via nucleophilic aromatic substitution to give the corresponding furanylene sulfide-containing polymers. Tensile measurements and spectral analyses demonstrate that the furanylene sulfide moieties form remarkably stable π–π stacking structures based on the enhanced dipole moment induced by sulfur linkages. When the polymer has a long spacer between repeating furanylene sulfide units, the polymer behaves as a chemically stable network polymer comprised of π–π stacking structures as cross-linking units. We developed 2,5-furanylene sulfide-containing polymers bearing different spacers as repeating units and evaluated the interactions between the furanylene sulfide units in the polymer. Treatment of a 2,5-dichlorofuran derivative with dithiolates at 200 °C promotes polycondensation via nucleophilic aromatic substitution to give the corresponding furanylene sulfide-containing polymers. Through tensile measurements and spectral analyses, it was found that the furanylene sulfide moieties form remarkably stable π–π stacking structures based on the enhanced dipole moment induced by sulfur linkages. When the polymer has a long spacer between repeating furanylene sulfide units, the polymer behaves as a chemically stable network polymer comprised of π–π stacking structures as cross-linking units.

A new species of fluorinated polymer surfactant was developed by three component polycondensation analogous to Ugi four-component condensation. The surfactant exhibited unique surface properties, which made cellulose-based materials hydrophobic and decreased the surface tension of CHCl3. It turned out that the polymer forms micelles in CHCl3.

Effective induction of preferred-handed helicity of polyacetylenes by the pendant mechanically chiral rotaxanes is discussed. Polyacetylenes possessing optically active mechanically chiral rotaxanes in the side chains were synthesized by the polymerization of the corresponding enantiopure [2]rotaxane-type ethynyl monomers prepared via the threading and end-capping protocol followed by the chiral HPLC separation. The CD Cotton effects revealed that the polyacetylenes took preferred-handed helical conformations depending on the rotaxane's chirality. The preferred-handed helix was not disturbed by the additional chiral substituent on the rotaxane side chain. These results for the first time demonstrate the significance and utility of mechanically chiral rotaxanes for the effective construction of asymmetric fields.

A vinylic supramolecular cross-linker (VSC) was prepared from γ- cyclodextrin ( γ- CD) and a macromonomer for the purpose of simple and easy introduction of rotaxane cross-links into polymers via the radical polymerization of vinyl monomers. The synthesis of VSC as a pseudocross-linked cross-linker was performed by the simple mixing of γ- CD and a poly(ethylene glycol)-based terminal-bulky macromonomer in water. The radical polymerization of typical vinyl monomers such as N,N -dimethyl acrylamide in the presence of the VSC afforded the corresponding rotaxane cross-linked polymers (RCPs) under both photoinitiated and redox polymerization conditions. In particular, RCPs exhibited mechanical properties endowed by the rotaxane cross-links that were superior to those of chemically cross-linked polymers, demonstrating the significant usefulness of the VSCs.

We developed a one-pot synthetic technique for alternating peptides. Central to this technique is a new, catalyst-free polymerization based on Ugi's 4CC reaction. The treatment of imines with the ambident molecules bearing both an isocyanide and a carboxylic acid afforded alternating peptides.

A series of N-substituted poly(Gly&ndash, alter&ndash, Val) peptides were successfully synthesized for the systematic evaluation of the micellization behavior of alternating peptides. Three-component polymerization employing an aldehyde, a primary ammonium chloride, and potassium isocyanoacetate afforded four alternating peptides in excellent yields. We investigated the dependence of the hydrophilic&ndash, lipophilic balance of alternating peptides on the micellization behavior. All the aqueous solutions of alternating peptides exhibited upper critical solution temperature (UCST) behaviors, strongly indicating that the alternating binary pattern would mainly contribute to the UCST behaviors. The cloud points of alternating peptides shifted to higher temperatures as the side chains became more hydrophilic, which is opposite to the trend of typical surfactants. Such unusual micellization behaviors appeared to be dependent on the quasi-stable structure of single polymer chains formed in water.

Graphical abstract, Highlights • One-pot synthetic pathway for glycyrrhetic acid polyglycosides was established. • The compounds were prepared via grafting reaction of cyclic sulfite 4 from the aglycon. • Cationic ring-opening polymerization of 4 gave (1 → 2)-linked polysaccharide skeletons. • Polymerization degree of the polymer was moderately controllable. • Thermodynamic parameters for degradation of 4 and glycal epoxide 3 were evaluated., Glycyrrhetic acid polyglycosides were synthesized in one-pot via cationic ring-opening condensation polymerization of cyclic sulfite (4) initiated by glycyrrhetic acid as an aglycon. Sulfite 4 worked as a practical monomer for the preparation of (1 → 2)-linked polysaccharide skeletons. The chemical stability of 4 was evaluated by the comparison of thermodynamic parameters with those of conventional epoxide (2). The grafting reaction of 4 from glycyrrhetic acid (5) was performed in the presence of TfOH and MS 3A in CH2Cl2 at room temperature. The polymerization degree was moderately controllable by the change of feed ratio of initiator.

13 C-labeled nitrile N -oxides ( 13 CNOs) were prepared to investigate the structural characteristics of nitrile N -oxide in solution. In the 13 C NMR spectra at room temperature, 13 C signals of 13 CNOs appeared at 35–38 ppm. The chemical shift of adjacent aromatic carbon C a to 13 CNO was remarkably upfield-shifted to indicate a positive mesomery effect of CNO. The 13 C NMR signal appeared as a triplet that originated from the scalar coupling of the adjacent 14 N nucleus, while it fused into a singlet as the temperature decreased. The UV spectra of 13 CNOs also indicated the temperature-dependent dynamic character of CNO.

This chapter provides an overview of the recent progress regarding click polymerizations using nitrile N-oxides applicable to various dipolarophiles. The pronounced reactivity of nitrile N-oxides enables metal (or catalyst)-free 1,3-dipolar cycloadditions with unsaturated bond-containing compounds such as alkynes, alkenes, and nitriles, indicating high potential in the synthesis of a variety of macromolecules and supramolecules via “click” molecular integration. For this purpose, kinetically stabilized nitrile N-oxides play a particularly important role. The first part of this chapter deals with the general topics of nitrile N-oxides, i.e. chemistry, synthetic methods, and reactions. The main discussion is divided into two parts: one is devoted to aromatic nitrile N-oxides, and the other is on aliphatic nitrile N-oxides, because these nitrile N-oxides have somewhat different features in terms of synthesis and reactivity. One of the most attractive features of nitrile N-oxides is that they undergo efficient cycloaddition under solvent-free conditions. Considering these features, it is obvious that nitrile N-oxides have very high potential to open a new world of click reactions and polymerizations. The number of publications mainly on polymerization using nitrile N-oxides is cited at the end of this chapter.

An effective method for the synthesis of the rotaxane cross-linked polymers (RCPs) was developed using a metal-containing supramolecular cross-linker (MSC). Radical polymerization of several vinyl monomers and bulky end-capped comonomer afforded RCPs in high yields. The obtained RCPs exhibited thermal properties corresponding to their respective polymer skeletons. Swelling ratio gradually increased with the decreasing amount of the steric comonomer units, indicating that the sliding ability of the movable cross-linker is strongly related to the swelling ability.

Polymeric quaterthiophenes containing optically active C2-chiral spirobifluorene skeletons were synthesized as a new type of helical foldamers, and their higher-order structures were investigated. Oxidization of quaterthiophene moieties caused the spacer units to be in planar structure, leading the conformation of the polymer to be a coil-shaped, rigid helix. This transformation was reversibly performed.

Poly(xanthon-3-ylmethacrylate) (poly(XOMA))and poly(xanthon-3-yl methacrylate-co-methyl methacrylate) (poly(XOMA-co-MMA)) having a pi-stacked conformation were synthesized as host material candidates for phosphorescence-based light emitting diodes. Poly(XOMA) harvested photo excitation energy for blue phosphorescent emission of iridium bis[(4,6-difluorophenyl) pyridinato-N, C-2] picolinate (FIrpic) in a CHCl3 solution and in film.

Two types of one-handed exact helical polymers, coil- and screw-shaped polymers, were synthesized by the two-point-covalent-linking protocol using C2-chiral spirobifluorene (SBF) and C2- or C(s)-symmetric anthraquinone spacers. Central to this protocol is a new aromatic ring-forming reaction based on the stepwise reductive cyclization of bis(aryloxy group)-substituted anthraquinone derivatives. The helical structures of the polymers annulated by aromatic skeletons exhibited high thermal stability attributed to the rigid C2-chiral SBF units and the covalently two-point-connected structure.

2-Methoxycarbonyl-3-(3,4-dimethoxyphenyl)oxirane was synthesized and polymerized using a cationic initiator to afford a polymer having a rather stiff, stretched conformation. The side-chain methoxycarbonyl group and 3,4-dimethoxyphenyl group of neighboring monomeric units may form a hetero π-stacked structure between side-chain carbonyl and aromatic groups which leads to intramolecular charge transfer (ICT) interactions. 2-Ethoxycarbonyl-3-phenyloxirane failed in polymerization, leading only to small molecules including cyclic compounds.

α-Cyclodextrin (CD)-based size-complementary [3]rotaxanes with alkylene axles were prepared in one-pot by end-capping reactions with aryl isocyanates in water. The selective formation of [3]rotaxane with a head-to-head regularity was indicated by the X-ray structural analyses. Thermal degradation of the [3]rotaxanes bearing appropriate end groups proceeded by stepwise dissociation to yield not only the original components but also [2]rotaxanes. From the kinetic profiles of the deslippage, it turned out that the maximum yield of [2]rotaxane was estimated to be 94 %. Thermodynamic studies and NOESY analyses of such rotaxanes revealed that [2]rotaxanes are specially stabilized, and that the dissociation capability of the [3]rotaxanes to the components can be adjusted by controlling the structure of the end groups, direction of the CD groups, and length of the alkylene axle.

1,2-O-Sulfinyl glucopyranose was used as a novel monomer for the synthesis of polysaccharide derivatives. It led to (1→2)-d-glucopyranan through cationic polymerization through the elimination of SO2, while anionic polymerization was rather complicated.

We describe the synthesis and properties of modified amylose containing an aryl spacer at a regular interval in its main chain as a new host polymer. The modified amylose was efficiently synthesized by copper-catalyzed alkyne–azide 1,3-dipolar cycloaddition polymerization of alkyne-containing permethylated maltohexaosyl azide 3. The polymer exhibited greater hydrophobicity than permethylated amylose. A mixture of the polymer with terthiophene formed an inclusion complex in a 10% dimethyl sulfoxide aqueous solution, leading to intermolecular chirality transfer from the polymer to terthiophene.

Fluorescent poly(boron enaminoketonate)s (PBEKs) were synthesized via the polycycloaddition of a homoditopic nitrile N-oxide to diynes followed by other polymer reactions. Click polycycloaddition of the nitrile N-oxide to various diynes effectively produced polyisoxazoles in high yields. The polyisoxazoles were transformed into the corresponding fluorescent PBEKs by forming the poly(β-aminoenone) intermediates and reacting these intermediates with (C6F5)2BF·OEt2. The solution and solid-state optical properties of the PBEKs were evaluated by ultraviolet–visible (UV–vis) and fluorescence spectroscopy. Fluorescent poly(boron enaminoketonate)s (PBEKs) were synthesized via polycycloaddition of homoditopic nitrile N-oxide to diynes and subsequent polymer reactions. Click polycycloaddition of the nitrile N-oxide to various diynes effectively produced polyisoxazoles in high yields. Transformation of the polyisoxazoles afforded the corresponding fluorescent PBEKs via intermediary formation of poly(β-aminoenone) followed by the reaction with (C6F5)2BF·OEt2. The optical properties of PBEKs were evaluated by the UV–vis and fluorescent spectra obtained under solution and solid states.

This review discusses seven synthetic approaches for fabricating topologically crosslinked polymers with rotaxane structures at the crosslinking points (rotaxane-crosslinked polymers, RCPs). RCPs exhibit unique properties such as high swelling capability, high elasticity and stimuli-responsiveness attributed to the rotaxane-crosslinking points. This article primarily focuses on the four most recently developed strategic approaches for synthesizing RCPs in which various rotaxane components, such as crown ethers/ammonium salts, cyclodextrins/hydrophobic guests and metal-coordinated macrocycles/ligands, are employed. Two of these RCP synthetic methods efficiently introduce special structures and functions into the RCP crosslinking points. Using these methods, we inserted well-studied rotaxane systems that exhibit deslipping behavior into the crosslinking points of network polymers. Notably, each of the resulting RCPs exhibited chemostimuli-responsive or photoresponsive degradability due to the deslipping behavior of the rotaxane system incorporated into the RCP. The other two methods are based on the use of rotaxane crosslinkers to fabricate versatile RCPs containing vinyl trunk polymers. The efficiencies and applications of these recently developed methods are compared with those of conventional methods. Topologically crosslinked polymers with rotaxane structures at the crosslinking points (rotaxane-crosslinked polymers, RCPs) have attracted great interest experimentally and theoretically. This focus review describes recent progress concerning the synthesis and applications of RCPs via four strategic approaches. Related research topics and further perspectives on RCPs are also discussed.

A one-pot synthesis of polymer nitrile N-oxides was achieved via the Michael addition of living polymer anions derived from vinyl monomers to commercially available trans-β-nitrostyrene and subsequent dehydration with concd H2SO4. The polymer nitrile N-oxides are effective as grafting agents in catalyst- and solvent-free 1,3-dipolar cycloadditions to unsaturated-bond-containing polymers with high conversion and exhibit higher reactivity compared to that of nitrile N-oxides prepared from 1,1-diphenylnitroethene. Application to the preparation of a functional glass surface was demonstrated using PtBMA nitrile N-oxide as a grafting agent.

An alternating copolymer consisting of achiral and chiral units emits remarkably efficient CPL on photo-excitation. The main-chain twist bias is enhanced by thermal annealing by the factor of 10(4) in the ground state. An anisotropy factor of the polymer in the excited state is greater by approximately an order of magnitude compared with that in the ground sate.

Stimuli-degradable cross-linked polymers were developed by applying both topological linkage and size complementarity of rotaxane to cross-link their structures. A double vinyl group-tethering [3]rotaxane cross-linker was prepared by reacting the axle ends of sec-ammonium/crown ether-type pseudo[3]rotaxane with a suitably bulky end-cap agent that was as large as the cavity of the wheel. Radical polymerization of a common vinyl monomer in the presence of the [3]rotaxane cross-linker afforded the corresponding stable cross-linked polymer under ambient conditions. An anion exchange reaction with tetra(n-butyl)ammonium chloride caused selective and efficient de-cross-linking of the cross-linked polymers to the vinyl polymer and the axle component of the cross-linker. Stimuli-degradable cross-linked polymers were developed by applying both topological linkage and size-complementarity of rotaxane to cross-link structure. Radical polymerization of a common vinyl monomer in the presence of the [3]rotaxane cross-linker gave the corresponding stable cross-linked polymer under ambient conditions. Anion exchange reaction with tetra(n-butyl)ammonium chloride caused the selective and efficient de-cross-linking of the cross-linked polymers to vinyl polymer and axle component of the cross-linker.