Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• ) Chemical structure of polyrotaxane 2; and (b) cartoon representation of the light-triggered degradation of rotaxane polymer 2 [52]. The key colour of the cartoon representation is analogous to that of the chemical structures. a) Chemical structures of rotaxanes (E)-3 and (Z)-3; b) stick representation of

One-pot synthesis of block-copolyrotaxanes through controlled rotaxa-polymerization

• Jessica Hilschmann,
• Gerhard Wenz and
• Gergely Kali

Beilstein J. Org. Chem. 2017, 13, 1310–1315, doi:10.3762/bjoc.13.127

• further effects the CD content and the aqueous solubility of the polyrotaxane. Keywords: block copolymer; cyclodextrin; polyisoprene; polyrotaxane; RAFT polymerization; Introduction Polymer necklaces, i.e., polyrotaxanes and pseudopolyrotaxanes, are supramolecular assemblies comprising polymeric axes

• polymers without chemical modification of the backbone. Through polyrotaxane formation solubility [2][3][4][5], as well as mechanical [1][2][3][6][7][8][9] and electrical properties [10], can be improved. Cross-linking of threaded macrocycles gives rise to so-called slide-ring gels with unique mechanical

• properties [6][11][12][13]. One of the most important class of important macrocycles, applied in polyrotaxane chemistry, are cyclodextrins (CDs) because they are nontoxic, biodegradable and available in industrial scale. Furthermore, CDs can be simply functionalized by modification of the hydroxy groups [14

Interactions between shape-persistent macromolecules as probed by AFM

• Johanna Blass,
• Jessica Brunke,
• Franziska Emmerich,
• Cédric Przybylski,
• Vasil M. Garamus,
• Artem Feoktystov,
• Roland Bennewitz,
• Gerhard Wenz and
• Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

• phenyl moieties and β-CD rings leading to daisy chains [54]. The polymerization of 7 was performed through Glaser coupling in pyridine catalyzed by Cu(I)/Cu(II). After removal of low molecular weight material by ultrafiltration polymer 8 was isolated as a light orange solid in 91% yield. Polyrotaxane

Versatile synthesis of end-reactive polyrotaxanes applicable to fabrication of supramolecular biomaterials

• Atsushi Tamura,
• Asato Tonegawa,
• Yoshinori Arisaka and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2016, 12, 2883–2892, doi:10.3762/bjoc.12.287

• functional PRXs and can be applied to the fabrication of PRX-based supramolecular biomaterials. Keywords: azide group; biomaterials; click chemistry; cyclodextrin; polyrotaxane; Introduction Polyrotaxanes (PRXs) are a class of interlocked polymers that consist of an inclusion complex of cyclodextrins (CDs

Superstructures with cyclodextrins: chemistry and applications III

• Gerhard Wenz and
• Eric Monflier

Beilstein J. Org. Chem. 2016, 12, 937–938, doi:10.3762/bjoc.12.91

• has been achieved in the synthesis of CD polyrotaxanes. The one-pot and one-step polyrotaxane synthesis of β-CDs was performed in aqueous solution by employing a click reaction [7] as well as by radical copolymerization [8]. Slide-ring gels, synthesized by the group of K. Ito through the crosslinking

Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

• Jie Wang,
• Zhiqiang Qiu,
• Yiming Wang,
• Li Li,
• Xuhong Guo,
• Duc-Truc Pham,
• Stephen F. Lincoln and
• Robert K. Prud’homme

Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7

• form hydrogels [84][85]. In particular, hydrogels formed by PEG and cyclodextrins have been investigated intensively because of the biocompatibility of their components. Interestingly, local crystallization of the polyrotaxane threaded cyclodextrins, sometimes called molecular necklaces [86], may form

• conditions, when several α-CD thread onto a single polymer chain to form a polyrotaxane they may aggregate in a localized crystalline state to effectively form cross-links between the polyrotaxanes in a hydrogel network [97][98][99]. A group of pH-responsive hydrogels which comprises four adamantyl

• polymer such that the aggregation of the hydrogel network increases. 5.3 Thermo-responsive materials In 2006, Kataoka et al. showed that an aqueous solution of the poly(ethylene glycol) polyrotaxane with adamantyl end-substituents (Figure 17) changes from a solution of single chains and small clusters of

Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

• Aurica Farcas,
• Giulia Tregnago,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert and
• Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

• evaluated and compared to those of the non-rotaxane counterpart 3. The influence of TM-βCD or TM-γCD encapsulation on the thermal stability, solubility in common organic solvents, film forming ability was also investigated. Polyrotaxane 3·TM-βCD exhibits a hypsochromic shift, while 3·TM-γCD displays a

• lifetime τ = 0.7 ns and 0.8 ns, whereas the 3·TM-γCD polyrotaxane shows a bi-exponential decay consisting of a main component (with a weight of 98% of the total luminescence) with a relatively short decay constant of τ1 = 0.7 ns and a minor component with a longer lifetime of τ2 = 5.4 ns (2%). The

• electrochemical band gap (ΔEg) of 3·TM-βCD polyrotaxane is smaller than that of 3·TM-γCD and 3, respectively. The lower ΔEg value for 3·TM-βCD suggests that the encapsulation has a greater effect on the reduction process, which affects the LUMO energy level value. Based on AFM analysis, 3·TM-βCD and 3·TM-γCD

Self-assemblies of γ-CDs with pentablock copolymers PMA-PPO-PEO-PPO-PMA and endcapping via atom transfer radical polymerization of 2-methacryloyloxyethyl phosphorylcholine

• Jing Lin,
• Tao Kong,
• Lin Ye,
• Ai-ying Zhang and
• Zeng-guo Feng

Beilstein J. Org. Chem. 2015, 11, 2267–2277, doi:10.3762/bjoc.11.247

• -chain-stranded; pentablock copolymer; poly(pseudorotaxane); polyrotaxane; single-chain-stranded; Introduction Cyclodextrins (CDs) are a series of macrocyclic molecules composed of 6, 7, or 8 (α-, β-, and γ-CD, respectively) glucopyranose units. Their hydrophilic surface and hydrophobic inner cavity

Synthesis, structure, and mechanical properties of silica nanocomposite polyrotaxane gels

• Kazuaki Kato,
• Daisuke Matsui,
• Koichi Mayumi and
• Kohzo Ito

Beilstein J. Org. Chem. 2015, 11, 2194–2201, doi:10.3762/bjoc.11.238

• property; nanocomposite; polyrotaxane; Introduction Nanocomposite materials, in which nanoparticles are distributed via a matrix such as resin or rubber, exhibit various functions that the matrix material cannot achieve by itself. For instance, polyurethane/magnetic nanoparticle nanocomposite elastomers

• generating systems, nanocomposites should satisfy both a high dielectric constant that is assured by the nanoparticles and a low elastic modulus [7]. Mechanically interlocked supramolecular polymers, such as polyrotaxane [8][9], can control the interface between the matrix polymer and the nanoparticles

• . Polyrotaxane comprising an end-capped backbone polymer and threaded cyclic molecules such as cyclodextrins (CDs) can form a network structure by intermolecular binding of the cyclic components [10]. Since the polymer chains are topologically connected to each other without chemical bonds, the chains can slide

Synthesis of an organic-soluble π-conjugated [3]rotaxane via rotation of glucopyranose units in permethylated β-cyclodextrin

• Jun Terao,
• Yohei Konoshima,
• Akitoshi Matono,
• Hiroshi Masai,
• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2014, 10, 2800–2808, doi:10.3762/bjoc.10.297

• synthesis of π-conjugated polymer-based IMWs using CD derivatives involve (I) threading π-conjugated polymers through CD [8][9] using a method developed by Harada for the synthesis of a polyrotaxane [10], (II) polymerization of pseudo [2]rotaxane monomer formed by self-inclusion of a π-conjugated guest with

• IMWs with polyrotaxane structures via polymerization of π-conjugated [1]rotaxane monomers bearing PMCDs as macrocycles [14]. Further, we confirmed that such IMWs with poly[1]rotaxane structure are highly soluble in a variety of organic solvents and have good rigidity, photoluminescence efficiency [15

Synthesis of a resin monomer-soluble polyrotaxane crosslinker containing cleavable end groups

• Ji-Hun Seo,
• Shino Nakagawa,
• Koichiro Hirata and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2014, 10, 2623–2629, doi:10.3762/bjoc.10.274

• Ji-Hun Seo Shino Nakagawa Koichiro Hirata Nobuhiko Yui Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, 101-0062, Japan Tokuyama Dental Corp. Research Institute, Tsukuba, 300-4247, Japan 10.3762/bjoc.10.274 Abstract A resin monomer-soluble polyrotaxane

• -soluble PRX crosslinker can be applied to design degradable photosetting plastics potentially used in the industrial or biomedical field. Keywords: α-cyclodextrin; composite resin; disulfide; polyrotaxane; Vickers hardness; Introduction Polyrotaxane (PRX) is a supermolecule containing host molecules

Synthesis of graft polyrotaxane by simultaneous capping of backbone and grafting from rings of pseudo-polyrotaxane

• Kazuaki Kato,
• Katsunari Inoue,
• Masabumi Kudo and
• Kohzo Ito

Beilstein J. Org. Chem. 2014, 10, 2573–2579, doi:10.3762/bjoc.10.269

• reaction yielded graft polyrotaxanes in a good yield, demonstrating a significant simplification of the synthesis of graft polyrotaxanes. Keywords: branch structure; cyclodextrin; end capping; graft polyrotaxane; polyrotaxane; Introduction Polyrotaxanes, interlocked molecules composed of polymer chains

• inclusion complex with CDs, 3) end capping, 4) chemical modification of CDs, and 5) grafting. The first three steps constitute the synthesis of polyrotaxane. The fourth process is necessary to dissociate the columnar crystal of CDs formed by hydrogen bonds and to disperse the CDs within the backbone

• necessary for complexation, it complicates the synthesis of GPRs. Here, we propose a new synthetic scheme for GPRs based on simultaneous end-capping and grafting reactions to directly produce a pseudo-polyrotaxane (pPR), as shown in Scheme 2. Since the CDs and the backbone polymer ends have hydroxy groups

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• addition, films characterized by a higher optical quality could be prepared by spin-coating from polyrotaxane solutions. The chemical structure of the synthesized copolymers were proved by FTIR and NMR spectroscopy. The FTIR spectra of 4a and 4b (Figure S3 in Supporting Information File 1) show all the

• , respectively. Figure 3 displays the 1H NMR spectrum of the 4a polyrotaxane copolymer with the assignments of the resonance peaks. The 1H NMR spectra of 4b and non-rotaxane 4 are shown in Figures S4 and S5 in Supporting Information File 1. The resonance peaks of l, m and n protons from monomer 1 are shifted

• upfield by more than 0.29 and 0.09 ppm in the polyrotaxane 4a compared to those of the non-rotaxane 4 counterpart (Figure 3 and Figure S4 in the Supporting Information File 1). A comparison of the integrals of (l + m + n) protons from monomer 1 to those corresponding to H1 protons of TMS-β-CD and TMS-γ-CD

Polysiloxane ionic liquids as good solvents for β-cyclodextrin-polydimethylsiloxane polyrotaxane structures

• Narcisa Marangoci,
• Rodinel Ardeleanu,
• Laura Ursu,
• Constanta Ibanescu,
• Maricel Danu,
• Mariana Pinteala and
• Bogdan C. Simionescu

Beilstein J. Org. Chem. 2012, 8, 1610–1618, doi:10.3762/bjoc.8.184

• complexes [10], etc. Polyrotaxane structures based on cyclodextrins and different linear (co)polymers are well known as supramolecular ensembles. They consist of cyclodextrin molecules whose hydrophobic cavities are penetrated by a linear polymer chain terminating with bulky stoppers, which prevent the

• , even if each component of their structure is soluble in a large number of solvents [8]. Research for new solvents has led to the discovery of ionic liquids as a good option for pseudo- or polyrotaxane structures [7][8][17][18]. It should be also mentioned that the mobility of the carrier ions of ILs

• polyrotaxane structures. Also, in the present study, we report how the rheological properties are influenced when CD-polydimethylsiloxane rotaxane is dissolved in PDMS-Im/S ionic liquid. Results and Discussion A class of polymers that possesses a unique combination of properties, such as very low Tg values

Supramolecular hydrogels formed from poly(viologen) cross-linked with cyclodextrin dimers and their physical properties

• Yoshinori Takashima,
• Yang Yuting,
• Miyuki Otsubo,
• Hiroyasu Yamaguchi and
• Akira Harada

Beilstein J. Org. Chem. 2012, 8, 1594–1600, doi:10.3762/bjoc.8.182

• adding selenium or platinum complexes yields supramolecular assemblies of bis(molecular tube)s cross-linked with the β-CD dimer, which form nanofibers [12][13][14][15]. Moreover, mechanically linked polyrotaxane with the α-CD and poly(ethylene glycol) (PEG) produces a hydrogel material, which exhibits

• unique physical properties [10]. Previously, we have prepared a polyrotaxane using α-CD and PEG [16][17]. The α-CD/PEG polyrotaxane forms a hydrogel material in high concentrations [18]. Using polyelectrolytes as threading molecules results in complexation between the polyelectrolyte and α-CD within the

• range of the 1H NMR time scale due to the slow equilibrium [19][20]. Cationic groups, such as pyridinium and pyridylpyridinium terminal groups, inhibit the decomposition of polyrotaxane and stabilize the complexes between α-CD and cationic alkanediyl compounds [21][22][23]. Herein, to study the

Synthesis and characterization of low-molecular-weight π-conjugated polymers covered by persilylated β-cyclodextrin

• Aurica Farcas,
• Ana-Maria Resmerita,
• Andreea Stefanache,
• Mihaela Balan and
• Valeria Harabagiu

Beilstein J. Org. Chem. 2012, 8, 1505–1514, doi:10.3762/bjoc.8.170

• -dioctylfluorene)-alt-5,5'-bithiophene/PS-βCD] (PDOF-BTc) polyrotaxane copolymer, through a Suzuki coupling reaction between the 5,5'-dibromo-2,2'-bithiophene (BT) inclusion complex with persilylated β-cyclodextrin (PS-βCD), and 9,9-dioctylfluorene-2,7-bis(trimethylene borate) (DOF) as the blocking group. The

• chemical structure and the thermal and morphological properties of the resulting polyrotaxane were investigated by using NMR and FT-IR spectroscopy, TGA, DSC and AFM analysis. The encapsulation of BT inside the PS-βCD cavity results in improvements in the solubility, as well as in different surface

• thermal as well as photophysical stability, and the ability to form good films [12][34]. Herein, we report the preparation and characterization of a main-chain polyrotaxane with alternating fluorene–bithiophene moieties covered by persilylated β-cyclodextrin (PS-βCD). Thus, poly[2,7-(9,9-dioctylfluorene