Radically Polymerizable Pseudorotaxane Monomers: Versatile Building Units for Side Chain Polyrotaxane Synthesis

Takata, Toshikazu; Kawasaki, Hiroaki; Asai, Satoko; Kihara, Nobuhiro; Furusho, Yoshio

doi:10.1246/cl.1999.111

Cited by 29 publications

(17 citation statements)

References 25 publications

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“…Ritter and coworkers 5 first reported side chain-type polyrotaxanes possessing bcyclodextrin wheels (first synthesis of side chain-type polyrotaxane), whereas crown ether-containing polyrotaxanes were synthesized by a few groups (cyclodextrine type; except for crown ether type). [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] However, some issues remain to be addressed in the construction of functionalized side chain-type polyrotaxanes, such as high polymerization degree, controlled rotaxane content, regular arrangement of rotaxane moietes and so on. These matters depend mainly on the low polymerizability of the rotaxane-containing monomer due to the wheel component working as a sterically hindered group toward the growing end; competitive occurrence of the dethreading of the wheel component during polymerization when a pseudorotaxane monomer is used; and a nonstereoregular main chain polymer being formed by the polymerization of vinylic monomer.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of acetylene-functionalized [2]rotaxane monomers directed toward side chain-type polyrotaxanes

Nakazono

Fukasawa

Sato

et al. 2010

Polym J

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A crown ether-ammonium salt-type rotaxane monomer was synthesized in a high yield using dibenzo-24-crown-8-ether and sec-ammonium salt having a hydroxy terminal by means of an end-capping reaction with an ethynyl benzoic acid. Its N-acetylated derivative was also synthesized in a quantitative yield using excess acetic anhydride and triethylamine. Novel side chain-type polyrotaxanes, that is, ammonium-type and neutral polyphenylacetylenes tethering rotaxane moieties in side chains with high molecular weights, were obtained in high yields by polymerizations with an Rh catalyst. The structures of the polymers were characterized by infrared, ultraviolet-visible (UV-vis) spectra and size exclusion chromatography. N-acetylation of the rotaxane moieties of the ammonium salt-type polymer resulted in the formation of a reddish-colored neutral polymer showing red-shifted UV-vis absorptions around 500 nm based on the conjugated main chain, according to the structural change of rotaxane side chains, that is, the change of the distance of the wheel component to the polyacetylene main chain. The solubility of the polymers was evaluated.

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Section: Introductionmentioning

confidence: 99%

Synthesis of acetylene-functionalized [2]rotaxane monomers directed toward side chain-type polyrotaxanes

Nakazono

Fukasawa

Sato

et al. 2010

Polym J

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“…[1][2][3][4][5][6][7][8][9] A large number of main-chain polyrotaxanes have been synthesized to date, along with several side-chain ones (Scheme 1). [1][2][3][4][5][6][7][8][9][10][11][12] Meanwhile, there are few reports on polyrotaxanes with backbones consisting of mechanical bonds as well as poly [2]catenanes. [13][14][15][16][17][18][19][20] Several groups have recently reported attempts to synthesize poly- [2]rotaxanes (daisy chains), obtaining cyclic dimers or trimers instead of the polymers.…”

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confidence: 99%

First poly[3]rotaxane synthesized through the noncovalent step‐growth polymerization of a homoditopic dumbbell compound and a macrocycle with a reversible thiol–disulfide interchange reaction

Oku

Furusho

Takata

2002

J. Polym. Sci. A Polym. Chem.

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Recent advances in synthetic supramolecular chemistry have led to an outburst of reports on interlocked macromolecules, such as polyrotaxanes. [1][2][3][4][5][6][7][8][9] A large number of main-chain polyrotaxanes have been synthesized to date, along with several side-chain ones (Scheme 1). [1][2][3][4][5][6][7][8][9][10][11][12] Meanwhile, there are few reports on polyrotaxanes with backbones consisting of mechanical bonds as well as poly[2]catenanes. [13][14][15][16][17][18][19][20] Several groups have recently reported attempts to synthesize poly-[2]rotaxanes (daisy chains), obtaining cyclic dimers or trimers instead of the polymers. [21][22][23][24][25] Therefore, the synthesis of this type of polyrotaxane is not only challenging but also promising for creating new polymer materials with unique physical properties. Recently, we reported a new synthetic method for [2]rotaxane (6) and [3]rotaxane (5) under thermodynamic control, which uses the reversible cleavage-recombination process of the disulfide bond in the presence of a catalytic amount of thiol. 26 -30 The yields of the rotaxanes can be well controlled by the solvent, concentration, and temperature because the whole process is reversible. Important features of this method are the efficient thioldisulfide interchange reaction under mild conditions and the tolerance of disulfide for many functional groups. [31][32][33][34] Therefore, this method is promising for the synthesis of more complex molecules such as polyrotaxanes. We report here the first synthesis of poly-[3]rotaxane (3) by the application of this method to homoditopic molecules. 35 Biscrown ether (2) was synthesized from dibenzo-24-crown-8 ether in four steps, 36 whereas bisammonium salt, with a disulfide bond at the center (1), was prepared according to our method (Scheme 2). 26 A CDCl 3 / CD 3 CN mixed solvent system was chosen to study the polymerization of 1 and 2: CD 3 CN confers solubility on 1, whereas CDCl 3 ensures the high stability constants of the complexation and improves the solubility of 2. We carried out the polymerization by allowing a mixture of 1 (0.10 M), 2 (0.10 M), and a catalytic amount of benzenethiol (0.004 M) in CDCl 3 /CD 3 CN (7/3) to stand at 50°C for 7 weeks. The resulting mixture was cooled and kept at room temperature until the system reached equilibrium (2 weeks). The progress of the polymerization was monitored by 1 H NMR, from which the degree of polymerization (DP) was estimated to be 7 (calculated from the rotaxanated ratio of 86%) at the equilibrium state. 37 The evaporation of the solvent gave 3 as a colorless solid. A gel permeation chromatography (GPC) analysis of 3 (with CHCl 3 as a solvent) showed a bimodal distribution, as shown in Figure 1. The number-average molecular weight (M n ) of the mixture was estimated to be 1.6 kg mol Ϫ1 , which was much smaller than 6.8 kg mol Ϫ1 , the value expected from the 1 H NMR spectrum. The retention time of the lower molecular weight part (LMW) was a little shorter than that

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“…Polymerization of [2]pseudorotaxane, which has a polymerizable monomer unit as an axle molecule, gives polyrotaxane. The obtained polyrotaxane can have a side chain without a rotaxane structure because the [2] pseudorotaxane monomer is in equilibrium with the free macrocyclic and axle molecule which is also incorporated in the polymer chain (Scheme 14.13a) [40,41]. [2]Rotaxane is also an attractive monomer for the side-chain polyrotaxane because of the interlocked structure.…”

Section: Strategies and Synthesis Of [3]rotaxanesmentioning

confidence: 99%

Structure and Dynamic Behavior of Organometallic Rotaxanes

Suzaki¹,

Abe²,

Chihara³

et al. 2011

Supramolecular Polymer Chemistry

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Radically Polymerizable Pseudorotaxane Monomers: Versatile Building Units for Side Chain Polyrotaxane Synthesis

Cited by 29 publications

References 25 publications

Synthesis of acetylene-functionalized [2]rotaxane monomers directed toward side chain-type polyrotaxanes

Synthesis of acetylene-functionalized [2]rotaxane monomers directed toward side chain-type polyrotaxanes

First poly[3]rotaxane synthesized through the noncovalent step‐growth polymerization of a homoditopic dumbbell compound and a macrocycle with a reversible thiol–disulfide interchange reaction

Structure and Dynamic Behavior of Organometallic Rotaxanes

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