A study has been conducted on the synthesis and characterization of a kind of novel polyrotaxanes comprisingα- cyclodextrins (α-CDs) threaded on triblock eopolymers with poly(ethylene glycol) (PEG) as a central axle...A study has been conducted on the synthesis and characterization of a kind of novel polyrotaxanes comprisingα- cyclodextrins (α-CDs) threaded on triblock eopolymers with poly(ethylene glycol) (PEG) as a central axle and flanked by two low molecular weight polystyrenes as outer stoppers.Styrene was allowed to telomerize with polypseudorotaxanes as chain transfer agents made from the self-assembly of a distal thiol-capped PEG with a varying amount ofα-CDs in the presence of a redox initiation system at 40~C i...展开更多
α-Cyclodextrin/poly(ethylene glycol)(α-CD/PEG) polyrotaxane nanoparticles were prepared via a self-assembly method. Anticancer drug methotrexate(MTX) was loaded in the nanoparticles. The interaction between MTX and ...α-Cyclodextrin/poly(ethylene glycol)(α-CD/PEG) polyrotaxane nanoparticles were prepared via a self-assembly method. Anticancer drug methotrexate(MTX) was loaded in the nanoparticles. The interaction between MTX and polyrotaxane was investigated. The formation, morphology, drug release and in vitro anticancer activity of the MTX loaded polyrotaxane nanoparticles were studied. The results show that the MTX could be efficiently absorbed on the nanoparticles, and hydrogen bonds were formed between MTX andα-CDs. The typical channel-type stacking assembly style of polyrotaxane nanoparticles was changed after MTX was loaded. The mean diameter of drug loaded polyrotaxane nanoparticles were around 200 nm and the drug loading content was as high as about 20%. Drug release profiles show that most of the loaded MTX was released within 8 hours and the cumulated release rate was as high as 98%. The blank polyrotaxane nanoparticles were nontoxicity to cells. The in vitro anticancer activity of the MTX loaded polyrotaxane nanoparticles was higher than that of free MTX.展开更多
A new double betaine 1,1′-（propane-1,3-diyl）dipyridinium-4-carboxylate L has been synthesized. Reaction of 1, 1′-（propane-1,3-diyl）dipyridinium-4-carboxylate tetrahydrate 1 with Co（ClO4）2-6H2O leads to the for...A new double betaine 1,1′-（propane-1,3-diyl）dipyridinium-4-carboxylate L has been synthesized. Reaction of 1, 1′-（propane-1,3-diyl）dipyridinium-4-carboxylate tetrahydrate 1 with Co（ClO4）2-6H2O leads to the formation of a new Co（Ⅱ） coordination compound, namely [Co（H2O）6]-2H2O-2L-2ClO4 2. The crystal structures of 1 and 2 have been determined by single-crystal X-ray diffraction method. Crystal data for 1. monoclinic, space group C2/c, a = 18.945（4）, b = 7.700（2）, c = l 1.888（2）A,β = 101.67（3）°, V = 1698.3（6） A^3, Z = 4, F（000） = 760.0, Dc = 1.402 g/cm^3, the final R = 0.0607 and wR = 0.1607 for 950 observed reflections （1 〉 2σ（I））; and those for 2： monoclinic, space group P21/c, a = 17.982（1）, b = 15.879 （1）, c = 7.0716（5）/A,β= 100.675（1）°, V= 1984.3（3） ,A^3 Z= 4, F（000） = 1010.0, Dc = 1.631 g/cm^3, the final R = 0.0316 and wR = 0.0896 for 3784 observed reflections （1 〉20（I））. Crystal structure analysis indicates that in 1, molecules of L in a ＂V-shaped＂ conformation are linked to chains sustained by O-H…O hydrogen bonds between carboxylate groups and solvent water molecules. The chains are joined by O-H…O and C-H…O hydrogen bonds to further expand into a three-dimensional structure. For 2, molecules of L in a ＂Z-shaped＂ conformation are linked by hydrogen bonds between carboxylate groups and aqua ligands to form a chain of loops running down the b axis. The （2D→2D） polythreading in compound 2 represents the mode of parallel interpenetration of 2D sheets, having polyrotaxane character.展开更多
Slide-ring structured polyrotaxanes with high molecular mobility and reversible conformational transition ability can achieve high performance and multifunctionality of the material in various applications.There have ...Slide-ring structured polyrotaxanes with high molecular mobility and reversible conformational transition ability can achieve high performance and multifunctionality of the material in various applications.There have been many reviews describing advances in the research of rotaxanes and polyrotaxanes.However,most of them typically focus on the precise synthesis of mechanically interlocked molecules and the control of microscopic molecular shuttles.In this review,we examine the effects of motion activity and conformational transition due to molecular slide on the performance of polyrotaxanes and the latest functional applications.Different designs of polyrotaxane-based functional materials are presented to improve the potential for applications including self-healing stretchable elastomers/gels,stimuli-responsive smart devices,battery electrode binders,and biomedical drug delivery.It is anticipated that this review will provide insights and guidance for future developments in the design,synthesis and application of polyrotaxane-based functional materials.展开更多
A facile one-pot synthesis of α-cyclodextrin-based polyrotaxane （PR） in aqueous solution is reported, where the peptide glutathione was used as the end-capping agent and the thiol-ene Michael addition was used as t...A facile one-pot synthesis of α-cyclodextrin-based polyrotaxane （PR） in aqueous solution is reported, where the peptide glutathione was used as the end-capping agent and the thiol-ene Michael addition was used as the end-capping reaction. Both polyrotaxanes with low threading ratio and high threading ratio were successfully obtained. In contrast to the conventionally used multiple-step synthesis methods and hydrophobic end cappers, this one-pot aqueous synthesis as well as the biocompatibility of the end-capping agent could result in a much more biocompatible PR to be used as biomaterials.展开更多
A new supramolecular self-assembly approach to construct micelles and reverse micelles was reported.Double-hydrophilic block copolymers poly(ethylene oxide)-b-poly(N-isopropylacrylamide) (PEO-b-PNIPAAm) was synthesize...A new supramolecular self-assembly approach to construct micelles and reverse micelles was reported.Double-hydrophilic block copolymers poly(ethylene oxide)-b-poly(N-isopropylacrylamide) (PEO-b-PNIPAAm) was synthesized via atom transfer radical polymerization (ATRP) using PEO macroinitiator.Because of the lower critical solution temperature (LCST) phase behavior of PNIPAAm,PEO-b-PNIPAAm block copolymers self-assembled to form PNIPAAm-core micelles at 40 ℃.The PNIPAAm-core micelles were disassembled to unimers when the temperature was decreased to 25 ℃.But the addition of α-cyclodextrins (α-CDs) could induce the formation of PNIPAAm-shell micelles because of the 'channel-type' crystallities induced by PEO/α-CDs polyrotaxanes.The assembly and disassembly procedure of micelles and reverse micelles were investigated by dynamic light scattering (DLS),X-ray diffraction (XRD),1H NMR and transmission electron microscopy (TEM).展开更多
Combining with XRD analysis, Fourier transform infrared （FTIR） spectroscopy is employed to discern the self-assembled structures of β-cyclodextrins （β-CDs） threaded onto the polymer backbone in the polyrotaxanes...Combining with XRD analysis, Fourier transform infrared （FTIR） spectroscopy is employed to discern the self-assembled structures of β-cyclodextrins （β-CDs） threaded onto the polymer backbone in the polyrotaxanes （PRs） by means of the relative changes of absorption intensity of the characteristic peaks of β-CDs at 1153 and 1025 cm^-1. For quantitative analysis, six parameters are proposed to describe the relative absorption intensity variations of these peaks associated with a channel-type crystal structure or a dispersed structure of β-CDs entrapped. Among them, absorbance ratio （AR）, relative absorbance difference （RAD） and transmittance difference （TD） values are suitable. When the AR, RAD and TD data get below 1.04, 4.8 and 1.27, respectively, the PRs obtained would possess a dispersed structure. If these values go beyond 1.32, 34,5 and 9.47, respectively, they would hold a channel-type crystal structure. This finding provides a useful judgment to distinguish the self-assembled structures of β-CDs residing along the polymer backbone in the PRs.展开更多
In this study polyrotaxane （PR）-based triblock copolymers were first synthesized via the atom transfer radical polymerization （ATRP） of N-isopropylacrylamide initiated with the self-assembly of a distal 2-bromoiso...In this study polyrotaxane （PR）-based triblock copolymers were first synthesized via the atom transfer radical polymerization （ATRP） of N-isopropylacrylamide initiated with the self-assembly of a distal 2-bromoisobutyryl end-capped Pluronie 17R4 with a varying amount of a-cyclodextrins （a-CDs） in the presence of CuCI/PMDETA at 25 ℃ in aqueous solution. The a-CDs entrapped on the copolymer chain were then linked with hexamethylene diisocyanate to give rise to novel slightly cross-linked polyrotaxanes （SCPRs） in DMF at 45 ℃. The structures of the PR-based triblock copolymers and SCPRs were characterized by 1H NMR, 13C CP/MAS, GPC and TGA analy- ses. The number-average molecular weight of the resulting SCPRs was nearly three and five times of their precursor after linking with a low polydispersity index range of 1.08--1.28. The thermo-responsive transition of both PR-based supramolecular polymers in aqueous solution was demonstrated by turbidity measurements and the self-aggregated morphologies were also evidenced by TEM observations.展开更多
Two novel [3]pseudorotaxanes can be selectively synthesized from four components through self-sorting processes, which provides a new strategy for the construction of a well-organized heteropolyrotaxane.
Thermo-responsive polyrotaxane (PR)-based triblock copolymers were synthesized via the atom transfer radical polymerization (ATRP) of N-isopropylacrylamide initiated with self-assemblies made from a distal 2-bromoisob...Thermo-responsive polyrotaxane (PR)-based triblock copolymers were synthesized via the atom transfer radical polymerization (ATRP) of N-isopropylacrylamide initiated with self-assemblies made from a distal 2-bromoisobutyryl end-capped Pluronic 17R4 (PPO14-PEG24-PPO14) with a varying amount of β-cyclodextrins (β-CDs) in the presence of Cu(I)Cl/PMDETA at 25 °C in aqueous solution. The molecular structure was characterized by means of H NMR, FTIR, WXRD, GPC, TGA and 1 DSC analyses. About half of β-CDs are still entrapped on the Pluronic 17R4 chain while the number of incorporated NIPAAm monomers is nearly a double feed value in the resulting copolymers. The aggregate morphologies in aqueous solution were evidenced by TEM observations. A two-step thermo-responsive transition arising from a combination of a polypseudorotaxane middle block with poly(N-isopropylacrylamide) flanking blocks was also demonstrated by turbidity measurements. Given their thermo-responsive behavior in aqueous solution, these PR-based triblock copolymers show the potential to be used as smart materials for the controlled drug delivery systems, biosensors, and the like.展开更多
基金supported by the National Natural Science Foundation of China (Nos.20374008 and 20674006).
文摘A study has been conducted on the synthesis and characterization of a kind of novel polyrotaxanes comprisingα- cyclodextrins (α-CDs) threaded on triblock eopolymers with poly(ethylene glycol) (PEG) as a central axle and flanked by two low molecular weight polystyrenes as outer stoppers.Styrene was allowed to telomerize with polypseudorotaxanes as chain transfer agents made from the self-assembly of a distal thiol-capped PEG with a varying amount ofα-CDs in the presence of a redox initiation system at 40~C i...
基金supported by National Science Foundation for Excellent Young Scholars (No. 51222304)National Science Foundation of China (NSFC, No.31170921,51133004)+1 种基金National Basic Research Program of China (National 973 program, No. 2011CB606206)program for Changjiang Scholars and Innovative Research Team in University (IRT1163)
文摘α-Cyclodextrin/poly(ethylene glycol)(α-CD/PEG) polyrotaxane nanoparticles were prepared via a self-assembly method. Anticancer drug methotrexate(MTX) was loaded in the nanoparticles. The interaction between MTX and polyrotaxane was investigated. The formation, morphology, drug release and in vitro anticancer activity of the MTX loaded polyrotaxane nanoparticles were studied. The results show that the MTX could be efficiently absorbed on the nanoparticles, and hydrogen bonds were formed between MTX andα-CDs. The typical channel-type stacking assembly style of polyrotaxane nanoparticles was changed after MTX was loaded. The mean diameter of drug loaded polyrotaxane nanoparticles were around 200 nm and the drug loading content was as high as about 20%. Drug release profiles show that most of the loaded MTX was released within 8 hours and the cumulated release rate was as high as 98%. The blank polyrotaxane nanoparticles were nontoxicity to cells. The in vitro anticancer activity of the MTX loaded polyrotaxane nanoparticles was higher than that of free MTX.
基金This work was financially supported by Liuhui Center for Applied Mathematics, Nankai University and Tianjin University (No. H10114)
文摘A new double betaine 1,1′-（propane-1,3-diyl）dipyridinium-4-carboxylate L has been synthesized. Reaction of 1, 1′-（propane-1,3-diyl）dipyridinium-4-carboxylate tetrahydrate 1 with Co（ClO4）2-6H2O leads to the formation of a new Co（Ⅱ） coordination compound, namely [Co（H2O）6]-2H2O-2L-2ClO4 2. The crystal structures of 1 and 2 have been determined by single-crystal X-ray diffraction method. Crystal data for 1. monoclinic, space group C2/c, a = 18.945（4）, b = 7.700（2）, c = l 1.888（2）A,β = 101.67（3）°, V = 1698.3（6） A^3, Z = 4, F（000） = 760.0, Dc = 1.402 g/cm^3, the final R = 0.0607 and wR = 0.1607 for 950 observed reflections （1 〉 2σ（I））; and those for 2： monoclinic, space group P21/c, a = 17.982（1）, b = 15.879 （1）, c = 7.0716（5）/A,β= 100.675（1）°, V= 1984.3（3） ,A^3 Z= 4, F（000） = 1010.0, Dc = 1.631 g/cm^3, the final R = 0.0316 and wR = 0.0896 for 3784 observed reflections （1 〉20（I））. Crystal structure analysis indicates that in 1, molecules of L in a ＂V-shaped＂ conformation are linked to chains sustained by O-H…O hydrogen bonds between carboxylate groups and solvent water molecules. The chains are joined by O-H…O and C-H…O hydrogen bonds to further expand into a three-dimensional structure. For 2, molecules of L in a ＂Z-shaped＂ conformation are linked by hydrogen bonds between carboxylate groups and aqua ligands to form a chain of loops running down the b axis. The （2D→2D） polythreading in compound 2 represents the mode of parallel interpenetration of 2D sheets, having polyrotaxane character.
基金The authors thank the National Natural Science Foundation of China(52173112 and 51873123)the Sichuan Provincial Natural Science Fund for Distinguished Young Scholars(2021JDJQ0017)for financial support.
文摘Slide-ring structured polyrotaxanes with high molecular mobility and reversible conformational transition ability can achieve high performance and multifunctionality of the material in various applications.There have been many reviews describing advances in the research of rotaxanes and polyrotaxanes.However,most of them typically focus on the precise synthesis of mechanically interlocked molecules and the control of microscopic molecular shuttles.In this review,we examine the effects of motion activity and conformational transition due to molecular slide on the performance of polyrotaxanes and the latest functional applications.Different designs of polyrotaxane-based functional materials are presented to improve the potential for applications including self-healing stretchable elastomers/gels,stimuli-responsive smart devices,battery electrode binders,and biomedical drug delivery.It is anticipated that this review will provide insights and guidance for future developments in the design,synthesis and application of polyrotaxane-based functional materials.
基金financially supported by the National Natural Science Foundation of China(No.21004038)
文摘A facile one-pot synthesis of α-cyclodextrin-based polyrotaxane （PR） in aqueous solution is reported, where the peptide glutathione was used as the end-capping agent and the thiol-ene Michael addition was used as the end-capping reaction. Both polyrotaxanes with low threading ratio and high threading ratio were successfully obtained. In contrast to the conventionally used multiple-step synthesis methods and hydrophobic end cappers, this one-pot aqueous synthesis as well as the biocompatibility of the end-capping agent could result in a much more biocompatible PR to be used as biomaterials.
基金Financial support from the National Natural Science Foundation of China (Nos.51333005,51103126,21374095,51303154) and the Fundamental Research Funds for the Central Universities (No.2013QNA4047)is gratefully acknowledged.
文摘A new supramolecular self-assembly approach to construct micelles and reverse micelles was reported.Double-hydrophilic block copolymers poly(ethylene oxide)-b-poly(N-isopropylacrylamide) (PEO-b-PNIPAAm) was synthesized via atom transfer radical polymerization (ATRP) using PEO macroinitiator.Because of the lower critical solution temperature (LCST) phase behavior of PNIPAAm,PEO-b-PNIPAAm block copolymers self-assembled to form PNIPAAm-core micelles at 40 ℃.The PNIPAAm-core micelles were disassembled to unimers when the temperature was decreased to 25 ℃.But the addition of α-cyclodextrins (α-CDs) could induce the formation of PNIPAAm-shell micelles because of the 'channel-type' crystallities induced by PEO/α-CDs polyrotaxanes.The assembly and disassembly procedure of micelles and reverse micelles were investigated by dynamic light scattering (DLS),X-ray diffraction (XRD),1H NMR and transmission electron microscopy (TEM).
基金Acknowledgements We acknowledge the support from the National Natural Science Foundation of China （Grant No. 209740150） and the Doctoral Program Foundation of Ministry of Education of China （Grant No. 20091101110029）.
文摘Combining with XRD analysis, Fourier transform infrared （FTIR） spectroscopy is employed to discern the self-assembled structures of β-cyclodextrins （β-CDs） threaded onto the polymer backbone in the polyrotaxanes （PRs） by means of the relative changes of absorption intensity of the characteristic peaks of β-CDs at 1153 and 1025 cm^-1. For quantitative analysis, six parameters are proposed to describe the relative absorption intensity variations of these peaks associated with a channel-type crystal structure or a dispersed structure of β-CDs entrapped. Among them, absorbance ratio （AR）, relative absorbance difference （RAD） and transmittance difference （TD） values are suitable. When the AR, RAD and TD data get below 1.04, 4.8 and 1.27, respectively, the PRs obtained would possess a dispersed structure. If these values go beyond 1.32, 34,5 and 9.47, respectively, they would hold a channel-type crystal structure. This finding provides a useful judgment to distinguish the self-assembled structures of β-CDs residing along the polymer backbone in the PRs.
基金This work was supported by the Natural Science Foundation of China （No. 20974015） and the Doctoral Program Foundation of Ministry of Education of China （No. 20091101110029）. Wang Jin also thanks the sup- port from YUMIAO foundation of Beijing Institute of Technology.
文摘In this study polyrotaxane （PR）-based triblock copolymers were first synthesized via the atom transfer radical polymerization （ATRP） of N-isopropylacrylamide initiated with the self-assembly of a distal 2-bromoisobutyryl end-capped Pluronie 17R4 with a varying amount of a-cyclodextrins （a-CDs） in the presence of CuCI/PMDETA at 25 ℃ in aqueous solution. The a-CDs entrapped on the copolymer chain were then linked with hexamethylene diisocyanate to give rise to novel slightly cross-linked polyrotaxanes （SCPRs） in DMF at 45 ℃. The structures of the PR-based triblock copolymers and SCPRs were characterized by 1H NMR, 13C CP/MAS, GPC and TGA analy- ses. The number-average molecular weight of the resulting SCPRs was nearly three and five times of their precursor after linking with a low polydispersity index range of 1.08--1.28. The thermo-responsive transition of both PR-based supramolecular polymers in aqueous solution was demonstrated by turbidity measurements and the self-aggregated morphologies were also evidenced by TEM observations.
基金National Natural Science Foundation of China(No.21602055)Sci-Tech Innovation Teams in Universities of Hunan Province for financial support
文摘Two novel [3]pseudorotaxanes can be selectively synthesized from four components through self-sorting processes, which provides a new strategy for the construction of a well-organized heteropolyrotaxane.
基金supported by the National Natural Science Foundation of China (20974015)the Doctoral Program Foundation of Ministry of Education of China (20091101110029)
文摘Thermo-responsive polyrotaxane (PR)-based triblock copolymers were synthesized via the atom transfer radical polymerization (ATRP) of N-isopropylacrylamide initiated with self-assemblies made from a distal 2-bromoisobutyryl end-capped Pluronic 17R4 (PPO14-PEG24-PPO14) with a varying amount of β-cyclodextrins (β-CDs) in the presence of Cu(I)Cl/PMDETA at 25 °C in aqueous solution. The molecular structure was characterized by means of H NMR, FTIR, WXRD, GPC, TGA and 1 DSC analyses. About half of β-CDs are still entrapped on the Pluronic 17R4 chain while the number of incorporated NIPAAm monomers is nearly a double feed value in the resulting copolymers. The aggregate morphologies in aqueous solution were evidenced by TEM observations. A two-step thermo-responsive transition arising from a combination of a polypseudorotaxane middle block with poly(N-isopropylacrylamide) flanking blocks was also demonstrated by turbidity measurements. Given their thermo-responsive behavior in aqueous solution, these PR-based triblock copolymers show the potential to be used as smart materials for the controlled drug delivery systems, biosensors, and the like.
