A convenient real-time monitoring of monomer concentration during living cationic ring-opening polymerizations of tetrahydrofuran（THF） initiated with methyl triflate（Me OTf） has been developed for kinetic investig...A convenient real-time monitoring of monomer concentration during living cationic ring-opening polymerizations of tetrahydrofuran（THF） initiated with methyl triflate（Me OTf） has been developed for kinetic investigation and determination of equilibrium monomer concentration（[M]e） via in situ FTIR spectroscopy in combination with a diamond tipped attenuated total reflectance（ATR） immersion probe. The polymerization rate was first order with respect to monomer concentration and initiator concentration from the linear slope of ln（[M]0-[M]e）/（[M]-[M]e） versus polymerization time at different temperatures in various solvents. [M]e decreased linearly with initial monomer concentration while increased exponentially with increasing polymerization temperature. The equilibrium also strongly depends on solvent polarity and its interaction with monomer. The equilibrium polymerization time（te） decreased with increasing solvent polarity and decreased linearly with increasing [M]0 in three solvents with different slopes to the same point of bulk polymerization in the absence of solvent. Equation of Mn,e = 72.1/（0.14–0.04[M]e） has been established to provide a simple and effective approach for the prediction for the number-average molecular weight of poly THFs at equilibrium state（Mn,e） in the equilibrium living cationic ring-opening polymerization of THF at 0 °C.展开更多
Cationic ring-opening polymerization of 3,3-bis（chloromethyl）oxacyclobutane catalyzed by BF3.OEt2 was carded out in ionic liquids [bmim]BF4 and [bmim]PF6. The influences of BCMO concentration and molar ratio of BCMO...Cationic ring-opening polymerization of 3,3-bis（chloromethyl）oxacyclobutane catalyzed by BF3.OEt2 was carded out in ionic liquids [bmim]BF4 and [bmim]PF6. The influences of BCMO concentration and molar ratio of BCMO/BF3.OEt2 on the molecular weights and yield of PBCMO were investigated. The polymerization in ionic liquids proceed to high conversions, although molecular weights are limited, similar to polymerization in organic solvent such as CH2Cl2. Follow a viewpoint of green chemistry, we feel ionic liquid [bmim]BF4 is superior to [bmim]PF6. Extracting [bmim]PF6 from the product using organic solvent as extractant limits its advantage as a green reaction media.展开更多
New highly stereoregular 2, 3 -di- O-(p-azidobenzyl )-(1 →5 ) - α-D -ribofuranan was synthesized byselective ring-opening polymerization of 1, 4-anhydro-2, 3 - di-O -(p-azidobenzyl )-α-D -ribopyranose(ADABR) using ...New highly stereoregular 2, 3 -di- O-(p-azidobenzyl )-(1 →5 ) - α-D -ribofuranan was synthesized byselective ring-opening polymerization of 1, 4-anhydro-2, 3 - di-O -(p-azidobenzyl )-α-D -ribopyranose(ADABR) using phosphorus pentafluoride or tin tetrachloride as catalyst at low temperature indichloromethane. The monomer was obtained by the reaction of p - bromomethyl -phenyleneazide with 1, 4 -anhydro-α-D-ribose in DMF. The structure of poly(ADANR) was identified by specific rotation and ^(13)C-NMR spectroscopy. Acid chloride-AgCl_4 complex catalyst such as CH_2=C(CH_3)C^+OClO_4^- used in thepolymerization resulted in polymers with mixed structures, i.e. (1→5)-α-D-ribofuranosidic and (1→4)-β-D-ribopyranosidic units. However, with C_6H_5C^+OClO_4^- as catalyst, pure (1→5)-α-D-ribofuranan was obtained.The effects of catalyst, polymerization temperature and time on polymer stereoregularity were examined, andthe mechanism of the ring-opening polymerization was discussed.展开更多
Living/controlled cationic ring-opening polymerization(ROP)of L-lactide is a promising approach to isotactic-rich and crystalline poly(L-lactide).In contrast with the unsubstituted lactones,L-LA can not be polymerized...Living/controlled cationic ring-opening polymerization(ROP)of L-lactide is a promising approach to isotactic-rich and crystalline poly(L-lactide).In contrast with the unsubstituted lactones,L-LA can not be polymerized by organic Lewis acids or carbenium ions,and the state of the art in this field is the cationic ROP of L-LA catalyzed by BrФnsted acid/alcohol system via activated monomer mechanism.Herein,we reported the first example of controlled cationic ROP of L-LA by using Meerweintype ion pair[Me_(3)O]^(+)[B(C_(6)F_(5))_(4)]^(-)as the catalyst.[Me_(3)O]^(+)[B(C_(6)F_(5))_(4)]^(-)promoted rapid L-LA cationic polymerization in the absence of alcohol,producing isotactic-rich and crystalline PLLA without transesterification and epimerization side reactions.An activated chain end mechanism,involving twice S_(N)2 substitution and configuration-inversion(S→R→S)with the assistance of released Me_(2)O,was proposed and further verified by density functional theory and control experiments.This work expands the catalytic toolbox of isotactic-rich and crystalline polylactide synthesis.It represents a unique example of cationic-controlled polymerization of L-LA catalyzed by an organic ion pair.展开更多
Cationic ring-opening copolymerization of 1, 4-anhydro-2, 3-O-isopropylidene-α-D-ribo-pyranose (AIRP) with 1,4-anhydro-2,3-di-O-benzyl-α-D-ribopyranose (ADBR) preparedfrom D-ribose was studied. Copolymerization usin...Cationic ring-opening copolymerization of 1, 4-anhydro-2, 3-O-isopropylidene-α-D-ribo-pyranose (AIRP) with 1,4-anhydro-2,3-di-O-benzyl-α-D-ribopyranose (ADBR) preparedfrom D-ribose was studied. Copolymerization using SbCl_5 or BF_3 OEt_2 as catalyst atlow temperature gave stereoregular (1→4)β-D-ribofuranan (C-1 and C-4 ring cleavagesee Scheme 1) or (1→5) α-D-ribofuranan (C-1 and C-5 ring cleavage) respectively. Theeffects of catalysts, reaction time and temperatures on yield and stereoregularity of the ob-tained polymers were studied. Polymers were characterized by molecular weight, ~1HNMR,^(13)CNMR and optical rotation.展开更多
As a powerful synthetic tool,ruthenium-catalyzed ring-opening metathesis polymerization(ROMP)has been widely utilized to prepare diverse heteroatom-containing polymers.In this contribution,we report the synthesis of t...As a powerful synthetic tool,ruthenium-catalyzed ring-opening metathesis polymerization(ROMP)has been widely utilized to prepare diverse heteroatom-containing polymers.In this contribution,we report the synthesis of the novel imine-based polymer through the copolymerization of cyclooctene with cyclic imine comonomer via ROMP.Because of the efficient hydrolysis reactions of the imine group,the generated copolymer can be easily degraded under mild condition.Moreover,the generated degradable product was the telechelic polymer bearing amine group,which was highly challenged for its direct synthesis.And this telechelic polymer could also be used for the further synthesis of new polymer through post-transformation.The introduction of imine unit in this work provides a new example of the degradable polymer synthesis.展开更多
Although solid-state polymer electrolytes(SPEs)are expected to solve the safety hazards and limited energy density in the energy storage systems,they still encounter an inferior electrode/electrolyte interface when pr...Although solid-state polymer electrolytes(SPEs)are expected to solve the safety hazards and limited energy density in the energy storage systems,they still encounter an inferior electrode/electrolyte interface when prepared in an ex situ manner.Recently,in situ polymerization of SPEs favor high interfacial infiltrability,improved interface contact,and reduced interface resistance,owing to the formation of a"superconformal"interface between electrode and electrolyte.Especially,in situ strategies employing ring-opening polymerization(ROP)are emerging as dazzling stars,further enabling moderate polymerization conditions,controllable molecular structure,and reduced interfacial side reaction.As the main monomers that can be in situ polymerized via the ROP strategy,cyclic ethers have been used to construct the CE-SPEs with many merits,including good battery electrochemical performances and a simple assembly process.Here,as a systematic summarization of the existing reports,this review focuses on the polymerization mechanism of ROP,the design principles of CE-SPEs electrolytes,and the recent application of in situ CE-SPEs.In particular,this review thoroughly discusses the selection of different cyclic monomers,initiators and various modification approaches in in situ fabricating CE-SPEs.Ending with offering future challenges and perspectives,this review envisions shedding light on the profound understanding and scientific guidance for further development of high-performance in situ CE-SPEs.展开更多
Living cationic polymerization of 4-acetoxystyrene(STO)was conducted in CH_(2)Cl_(2) at-15℃ using a dicumyl chloride(DCC)/SnCl_(4)/nBu_(4)NBr initiating system.Impurity moisture initiation was inhibited by adding pro...Living cationic polymerization of 4-acetoxystyrene(STO)was conducted in CH_(2)Cl_(2) at-15℃ using a dicumyl chloride(DCC)/SnCl_(4)/nBu_(4)NBr initiating system.Impurity moisture initiation was inhibited by adding proton trap 2,6-di-tert-butylpyridine(DTBP),and the controlled initiation of DCC was confirmed by ^(1)H nuclear magnetic resonance(^(1)H-NMR)spectroscopy and matrix-assisted laser desorption ionization time-offlight mass(MALDI-TOF-MS)spectrometry.The polymerization kinetics were analyzed to for optimizing the polymerization rate.Allyl-telechelic PSTOs(allyl-PSTO-allyl)with molecular weight(Mn)range of 3540–7800 g/mol and narrow molecular weight dispersity(Mw/Mn)about 1.25 were prepared through nucleophilic substitution with allyltrimethylsilane(ATMS)at approximately 40%monomer conversion.The experimental results indicate that the substitution efficiency of ATMS increased with higher ATMS concentration,temperature,and extended reaction time.Nearly unity ally-functionality for allyl-PSTO-allyl was achieved by adding sufficient SnCl_(4) prior to the substitution.展开更多
Chemically recyclable polythioesters are of particular interest owing to their unique properties and desired sustainability.By the exploit of a benzo-fusion strategy toε-thiocaprolactone,we successfully improved the ...Chemically recyclable polythioesters are of particular interest owing to their unique properties and desired sustainability.By the exploit of a benzo-fusion strategy toε-thiocaprolactone,we successfully improved the chemical recyclability and regulated the thermal and mechanical properties of the resulting polythioesters.The efficient ring-opening polymerization(ROP)of benzo-fused thiolactone monomers(M)containing different substituents gave rise to high-molecular-weight semi-aromatic polythioesters P(M)s.The resulting P(M)s showcased tunable physical and mechanical properties.The debenzylation of P(M3)was able to generate P(M3-OH)with free hydroxyl sidechains.Notably,chemical recycling of the resulting P(M)s back to their corresponding monomers via bulk thermal depolymerization achieved high efficiency(>95%yield,99%purity),establishing a closed-loop lifecycle.展开更多
Mechanochromic polyolefins represent a novel class of functionalized polyolefins,which still remains significant challenges.Pd(II)-catalyzed coordination-insertion copolymerization is a feasible method for achieving t...Mechanochromic polyolefins represent a novel class of functionalized polyolefins,which still remains significant challenges.Pd(II)-catalyzed coordination-insertion copolymerization is a feasible method for achieving this kind of polymers,yet with linear microstructures.Ringopening metathesis polymerization(ROMP)offers another promising avenue for affording functionalized polyolefins.This method exhibits high polar group tolerance and the ability to precisely regulate polymer branches.In this study,we report the method for producing mechanochromic branched polyethylenes via ROMP.By employing the terpolymerization of a well-designed monomer containing the mechanochromic group,NB-ABF,with cyclooctene(COE)and long-chain 5-hexylcyclooctene(COE-C6),following by hydrogenation process,we synthesized a range of functionalized branched polyethylenes characterized by varied branching density and polar monomer incorporation.These polymers bear a structural resemblance to functionalized ethylene-octene copolymers.After crosslinking,mechanochromophores are generated,and mechanochromism is achieved in uniaxial tensile testing.A comprehensive assessment reveals that both the incorporation of polar monomers and variations in branching density significantly influence their mechanical properties.Notably,upon stretching,these materials display pronounced visible color change,confirming the successful development of mechanochromic branched polyethylenes.展开更多
Practical Zn metal batteries have been hindered by several challenges,including Zn dendrite growth,undesirable side reactions,and unstable electrode/electrolyte interface.These issues are particularly more serious in ...Practical Zn metal batteries have been hindered by several challenges,including Zn dendrite growth,undesirable side reactions,and unstable electrode/electrolyte interface.These issues are particularly more serious in low-concentration electrolytes.Herein,we design a Zn salt-mediated electrolyte with in situ ring-opening polymerization of the small molecule organic solvent.The Zn(TFSI)_(2)salt catalyzes the ring-opening polymerization of(1,3-dioxolane(DOL)),generating oxidation-resistant and non-combustible long-chain polymer(poly(1,3-dioxolane)(pDOL)).The pDOL reduces the active H_(2)O molecules in electrolyte and assists in forming stable organic–inorganic gradient solid electrolyte interphase with rich organic constituents,ZnO and ZnF_(2).The introduction of pDOL endows the electrolyte with several advantages:excellent Zn dendrite inhibition,improved corrosion resistance,widened electrochemical window(2.6 V),and enhanced low-temperature performance(freezing point=-34.9°C).Zn plating/stripping in pDOL-enhanced electrolyte lasts for 4200 cycles at 99.02%Coulomb efficiency and maintains a lifetime of 8200 h.Moreover,Zn metal anodes deliver stable cycling for 2500 h with a high Zn utilization of 60%.A Zn//VO_(2)pouch cell assembled with lean electrolyte(electrolyte/capacity(E/C=41 mL(Ah)^(-1))also demonstrates a capacity retention ratio of 92%after 600 cycles.These results highlight the promising application prospects of practical Zn metal batteries enabled by the Zn(TFSI)2-mediated electrolyte engineering.展开更多
Aliphatic polyesters and polycarbonates are among the promising sustainable polymers,which exhibit unique degradability and chain-chain interactions owing to their heterofunctionality.However,monocomponent aliphatic p...Aliphatic polyesters and polycarbonates are among the promising sustainable polymers,which exhibit unique degradability and chain-chain interactions owing to their heterofunctionality.However,monocomponent aliphatic polyesters and polycarbonates usually suffer from inferior properties and functionalities.By contrast,precisely modulated block copolymers composed of polyesters and polycarbonates give rise to sustainable materials with tailored performance.An efficient approach to synthesize the block copolymers is the ring-opening(co)polymerization of the heterocycle monomers.Herein,this review presents the heterocycle monomer ring-opening(co)polymerization for the formation of sequence-controlled block polyesters and polycarbonates.Available synthetic strategies,different monomers,monomer combinations and the catalyst systems for the formation of different block polyesters and polycarbonates are summarized.展开更多
A series of bis-ligated zinc complexes supported by Schitt base ligands were successfully synthesized and characterized by 1 H, 13C NMR, elemental analysis, and X-ray crystallography. These zinc complexes can be used ...A series of bis-ligated zinc complexes supported by Schitt base ligands were successfully synthesized and characterized by 1 H, 13C NMR, elemental analysis, and X-ray crystallography. These zinc complexes can be used as catalysts for the polymerization of rac-lactide in solution as well as in molten lactide. The results show that all catalysts exhibited high catalytic activity and obtained moderate heterotactic PLAs with the expected molecular weight. Complex 1 can catalyze the polymerization of rac-lactide under controllable conditions with living and immortal character in toluene solution. In addition, the steric hindrance and electronic effects has a great influence on the catalytic activity and selectivity of catalysts.展开更多
Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford prod...Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.展开更多
Despite the growing interest in fast-cha rging solid-state lithium(Li)-metal batteries(SSLMBs),their practical implementation has yet to be achieved,primarily due to an incomplete understanding of the disparate and of...Despite the growing interest in fast-cha rging solid-state lithium(Li)-metal batteries(SSLMBs),their practical implementation has yet to be achieved,primarily due to an incomplete understanding of the disparate and often conflicting requirements of the bulk electrolyte and the electrode-electrolyte interphase.Here,we present a weakly coordinating cationic polymer electrolyte(WCPE)specifically designed to regulate the Li^(+)coordination structure,thereby enabling fast-charging SSLMBs.The WCPE comprises an imidazolium-based polycationic matrix combined with a succinonitrile(SN)-based highconcentration electrolyte.Unlike conventional neutral polymer matrices,the polycationic matrix in the WCPE competes with Li^(+)for interactions with SN,weakening the original coordination between SN and Li^(+).This modulation of SN-Li^(+)interaction improves both Li^(+)conductivity of the WCPE(σ_(Li^(+))=1.29mS cm^(-1))and redox kinetics at the electrode-electrolyte interphase.Consequently,SSLMB cells(comprising LiFePO_(4)cathodes and Li-metal anodes)with the WCPE achieve fast-charging capability(reaching over 80%state of charge within 10 min),outperforming those of previously reported polymer electrolytebased SSLMBs.展开更多
A novel simple but effective initiating system of H2O/AlCl3/veratrole （VE） has been developed to synthesize high molecular weight polyisobutylene （PIB） at elevated temperatures via cationic polymerization of isobu...A novel simple but effective initiating system of H2O/AlCl3/veratrole （VE） has been developed to synthesize high molecular weight polyisobutylene （PIB） at elevated temperatures via cationic polymerization of isobutylene （IB） in solvent mixture of hexane/methylene dichloride （n-Hex/CH2Cl2 = 2/1, V/V）. VE played very important roles in decreasing cationicity of the growing chain ends, suppressing side reactions of chain transfer and termination during polymerization, leading to production of high molecular weight PIBs. PIBs with high yields, having very high weight-average molecular weight （Mw） of 1117000 and 370000 g/tool could be synthesized with H2O/AICl3/VE initiating system at VE concentration of 5.4 mmol/L at -80 and -60 ℃ respectively. Molecular weight of PIB increased remarkably with increasing VE concentration. The reaction order with respect to VE concentration was determined to be -3.52 via FTIR spectroscopy in combination with a diamond tipped attenuated total reflectance （ATR） immersion probe. The negative reaction order of VE was consistent with its retarding effect on IB polymerization by interacting with the propagating species. Molecular weight of PIB decreased with increasing polymerization temperature. The activation energy for polymerization degree （Eop） could be determined to be around -23 kJ/mol when VE concentration was 5.4 mmol/L or 6.4 mmol/L.展开更多
The cationic polymerizations of isobutylene （IB） coinitiated by AlCl3 were carried out in solvent mixture of nhexane/methylene dichloride （n-hex/CH2Cl2） of 60/40 V/V in the presence of ethyl benzoate （EB） at var...The cationic polymerizations of isobutylene （IB） coinitiated by AlCl3 were carried out in solvent mixture of nhexane/methylene dichloride （n-hex/CH2Cl2） of 60/40 V/V in the presence of ethyl benzoate （EB） at various temperatures range from -80℃ to -30℃. The effects of EB concentration （[EB]） and polymerization temperature on monomer conversion, weight-average molecular weight （Mw） and molecular weight distribution （MWD, Mw/Mn） of polyisobutylene （PIB） products were investigated. The rate of polymerization decreased while Mw of PIB products increased with increasing [EB]. The polymers with high molecular weight could be prepared in the presence of a suitable amount of EB. Significantly, the polymers with high Mw of 80.2 × 10^4 and 65.4 × 10^4 could be produced at -80℃ and -70℃ at [EB] = 0.24 × 10^3 mol/L respectively, which were much higher than that （Mw = 57.9 × 10^4） of PIB prepared at -100℃ in the absence ofEB. A simple but effective method for preparing the high molecular weight polyisobutylenes was developed in this work. It has been also found that the activation energy for propagation （Ep） depended on the polymerization temperature range in the presence of EB. An obvious inflection of the linear plots of lnXn versus 1/Tp occurred at the temperature range from -60℃ to -50℃ at four different concentrations of EB from 0.19 × 10^3 mol/L to 0.33× 10^3 tool/L, and thus the inflection temperature （Tinf） was in the range of -60℃ to -50℃. When [EB] was in the range of 0.24 × 10^3 mol/L to 0.33× 10^3 mol/L, Ep was determined to be around -12 kJ/mol when the polymerization was carried out at temperatures from -80℃ to Tinf and to be around -28 kJ/mol at temperatures from Tinf to -15℃ respectively.展开更多
Cationic ring opening polymerization of octamethylcyclotetrasiloxane （Da） initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary experiments.Higher ...Cationic ring opening polymerization of octamethylcyclotetrasiloxane （Da） initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary experiments.Higher temperature was found beneficial for the reaction process while stirring intensity beyond a certain level showed no obvious effect on the reaction rate. Polymers were characterized by Fourier transform infrared, proton nuclear magnetic resonance （IH-NMR） and gel perneation chromotography. The width of molecular mass distribution was found ranging between 1.2 and 1.4, which is extraordinarlly narrow compared with that of cationic polymerizations reported elsewhere （〉 1.9）. The results were believed due to the absence of free proton and counter ion which simplifies the polymerization process and the huge steric hindrance provided by bentonite particles which keeps the propagation of polysiloxane onto the surface of bentonite particles in a much more regular way. A feasible mechanism is proposed and seems to be supported well by experiments. Additionally, from the results of α, ω-dihydrogen terminated polysiloxanes prepared, the possibility of applying this potential environmentally friendly heterogeneous catalyst in industrial polymerization of cyclosiloxanes is anticipated.展开更多
Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxid...Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxide, three stages are identified by kinetic study including(1) fast cationic polymerization with slow anionic one,(2) fast anionic polymerization with dormant cationic one, and(3)reactivation of cationic polymerization with coupling of anionic and cationic chain ends. In this work, density functional theory(DFT)calculation is employed to investigate the reaction details of ionic polymerization and dormancy. A “tripedal crow” configuration is proposed to illustrate the unique high-coordinated ligand exchange configuration in anionic polymerization in different stages. The trigger of dormancy is determined as chain structures rather than concentration of triflate anion according to both calculation and experimental results.展开更多
Highly potent ionic organocatalyst is developed for room-temperature controlled ring-opening polymerization(ROP)of lactones,includingδ-valerolactone,ε-caprolactone,andδ-hexalactone.The catalysts are prepared by sim...Highly potent ionic organocatalyst is developed for room-temperature controlled ring-opening polymerization(ROP)of lactones,includingδ-valerolactone,ε-caprolactone,andδ-hexalactone.The catalysts are prepared by simply mixing tetra-n-butyl ammonium hydroxide and a(thio)urea at elevated temperature under vacuum,and used in cooperation with an alcoholic initiator.The performance of the catalyst is readily adjusted and optimized through variation of the(thio)urea precursor,catalyst composition,and reaction condition.Urea-derived catalysts are generally superior to thiourea-derived ones.Provided with proper N-substituents,the catalyst affords both high polymerization efficiency and high selectivity for monomer enchainment over macromolecular transesterification,even at high monomer conversion and/or substantially extended reaction time.In addition to acidity,structural symmetry of the urea also proves decisive for the catalytic activity,which enables a catalyst-assisted proton transfer process for the ring-opening of lactone and thus provides a novel mechanistic insight for ROP catalyzed by hydrogen-bonding type bifunctional ionic organocatalysts.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51173008 and 51221002)
文摘A convenient real-time monitoring of monomer concentration during living cationic ring-opening polymerizations of tetrahydrofuran（THF） initiated with methyl triflate（Me OTf） has been developed for kinetic investigation and determination of equilibrium monomer concentration（[M]e） via in situ FTIR spectroscopy in combination with a diamond tipped attenuated total reflectance（ATR） immersion probe. The polymerization rate was first order with respect to monomer concentration and initiator concentration from the linear slope of ln（[M]0-[M]e）/（[M]-[M]e） versus polymerization time at different temperatures in various solvents. [M]e decreased linearly with initial monomer concentration while increased exponentially with increasing polymerization temperature. The equilibrium also strongly depends on solvent polarity and its interaction with monomer. The equilibrium polymerization time（te） decreased with increasing solvent polarity and decreased linearly with increasing [M]0 in three solvents with different slopes to the same point of bulk polymerization in the absence of solvent. Equation of Mn,e = 72.1/（0.14–0.04[M]e） has been established to provide a simple and effective approach for the prediction for the number-average molecular weight of poly THFs at equilibrium state（Mn,e） in the equilibrium living cationic ring-opening polymerization of THF at 0 °C.
基金financially supported by the Key Project of Chinese Ministry of Education(No.105075)the National Natural Science Foundation of China(No.20503016).
文摘Cationic ring-opening polymerization of 3,3-bis（chloromethyl）oxacyclobutane catalyzed by BF3.OEt2 was carded out in ionic liquids [bmim]BF4 and [bmim]PF6. The influences of BCMO concentration and molar ratio of BCMO/BF3.OEt2 on the molecular weights and yield of PBCMO were investigated. The polymerization in ionic liquids proceed to high conversions, although molecular weights are limited, similar to polymerization in organic solvent such as CH2Cl2. Follow a viewpoint of green chemistry, we feel ionic liquid [bmim]BF4 is superior to [bmim]PF6. Extracting [bmim]PF6 from the product using organic solvent as extractant limits its advantage as a green reaction media.
文摘New highly stereoregular 2, 3 -di- O-(p-azidobenzyl )-(1 →5 ) - α-D -ribofuranan was synthesized byselective ring-opening polymerization of 1, 4-anhydro-2, 3 - di-O -(p-azidobenzyl )-α-D -ribopyranose(ADABR) using phosphorus pentafluoride or tin tetrachloride as catalyst at low temperature indichloromethane. The monomer was obtained by the reaction of p - bromomethyl -phenyleneazide with 1, 4 -anhydro-α-D-ribose in DMF. The structure of poly(ADANR) was identified by specific rotation and ^(13)C-NMR spectroscopy. Acid chloride-AgCl_4 complex catalyst such as CH_2=C(CH_3)C^+OClO_4^- used in thepolymerization resulted in polymers with mixed structures, i.e. (1→5)-α-D-ribofuranosidic and (1→4)-β-D-ribopyranosidic units. However, with C_6H_5C^+OClO_4^- as catalyst, pure (1→5)-α-D-ribofuranan was obtained.The effects of catalyst, polymerization temperature and time on polymer stereoregularity were examined, andthe mechanism of the ring-opening polymerization was discussed.
基金supported by the National Natural Science Foundation of China(52222302)。
文摘Living/controlled cationic ring-opening polymerization(ROP)of L-lactide is a promising approach to isotactic-rich and crystalline poly(L-lactide).In contrast with the unsubstituted lactones,L-LA can not be polymerized by organic Lewis acids or carbenium ions,and the state of the art in this field is the cationic ROP of L-LA catalyzed by BrФnsted acid/alcohol system via activated monomer mechanism.Herein,we reported the first example of controlled cationic ROP of L-LA by using Meerweintype ion pair[Me_(3)O]^(+)[B(C_(6)F_(5))_(4)]^(-)as the catalyst.[Me_(3)O]^(+)[B(C_(6)F_(5))_(4)]^(-)promoted rapid L-LA cationic polymerization in the absence of alcohol,producing isotactic-rich and crystalline PLLA without transesterification and epimerization side reactions.An activated chain end mechanism,involving twice S_(N)2 substitution and configuration-inversion(S→R→S)with the assistance of released Me_(2)O,was proposed and further verified by density functional theory and control experiments.This work expands the catalytic toolbox of isotactic-rich and crystalline polylactide synthesis.It represents a unique example of cationic-controlled polymerization of L-LA catalyzed by an organic ion pair.
文摘Cationic ring-opening copolymerization of 1, 4-anhydro-2, 3-O-isopropylidene-α-D-ribo-pyranose (AIRP) with 1,4-anhydro-2,3-di-O-benzyl-α-D-ribopyranose (ADBR) preparedfrom D-ribose was studied. Copolymerization using SbCl_5 or BF_3 OEt_2 as catalyst atlow temperature gave stereoregular (1→4)β-D-ribofuranan (C-1 and C-4 ring cleavagesee Scheme 1) or (1→5) α-D-ribofuranan (C-1 and C-5 ring cleavage) respectively. Theeffects of catalysts, reaction time and temperatures on yield and stereoregularity of the ob-tained polymers were studied. Polymers were characterized by molecular weight, ~1HNMR,^(13)CNMR and optical rotation.
基金financially supported by National Key R&D Program of China(No.2021YFA1501700)CAS Project for Young Scientists in Basic Research(No.YSBR-094)+1 种基金Natural Science Foundation of Anhui Province(Nos.2308085Y35 and 2023AH030002)Hefei Natural Science Foundation(No.202304)。
文摘As a powerful synthetic tool,ruthenium-catalyzed ring-opening metathesis polymerization(ROMP)has been widely utilized to prepare diverse heteroatom-containing polymers.In this contribution,we report the synthesis of the novel imine-based polymer through the copolymerization of cyclooctene with cyclic imine comonomer via ROMP.Because of the efficient hydrolysis reactions of the imine group,the generated copolymer can be easily degraded under mild condition.Moreover,the generated degradable product was the telechelic polymer bearing amine group,which was highly challenged for its direct synthesis.And this telechelic polymer could also be used for the further synthesis of new polymer through post-transformation.The introduction of imine unit in this work provides a new example of the degradable polymer synthesis.
基金supported by the National Natural Science Foundation of China(22022813)the Zhejiang Provincial Natural Science Foundation of China(LQ24B030002)the China Postdoctoral Science Foundation(2022M722729,2023T160571).
文摘Although solid-state polymer electrolytes(SPEs)are expected to solve the safety hazards and limited energy density in the energy storage systems,they still encounter an inferior electrode/electrolyte interface when prepared in an ex situ manner.Recently,in situ polymerization of SPEs favor high interfacial infiltrability,improved interface contact,and reduced interface resistance,owing to the formation of a"superconformal"interface between electrode and electrolyte.Especially,in situ strategies employing ring-opening polymerization(ROP)are emerging as dazzling stars,further enabling moderate polymerization conditions,controllable molecular structure,and reduced interfacial side reaction.As the main monomers that can be in situ polymerized via the ROP strategy,cyclic ethers have been used to construct the CE-SPEs with many merits,including good battery electrochemical performances and a simple assembly process.Here,as a systematic summarization of the existing reports,this review focuses on the polymerization mechanism of ROP,the design principles of CE-SPEs electrolytes,and the recent application of in situ CE-SPEs.In particular,this review thoroughly discusses the selection of different cyclic monomers,initiators and various modification approaches in in situ fabricating CE-SPEs.Ending with offering future challenges and perspectives,this review envisions shedding light on the profound understanding and scientific guidance for further development of high-performance in situ CE-SPEs.
基金financially supported by the National Natural Science Foundation of China(No.52373011)。
文摘Living cationic polymerization of 4-acetoxystyrene(STO)was conducted in CH_(2)Cl_(2) at-15℃ using a dicumyl chloride(DCC)/SnCl_(4)/nBu_(4)NBr initiating system.Impurity moisture initiation was inhibited by adding proton trap 2,6-di-tert-butylpyridine(DTBP),and the controlled initiation of DCC was confirmed by ^(1)H nuclear magnetic resonance(^(1)H-NMR)spectroscopy and matrix-assisted laser desorption ionization time-offlight mass(MALDI-TOF-MS)spectrometry.The polymerization kinetics were analyzed to for optimizing the polymerization rate.Allyl-telechelic PSTOs(allyl-PSTO-allyl)with molecular weight(Mn)range of 3540–7800 g/mol and narrow molecular weight dispersity(Mw/Mn)about 1.25 were prepared through nucleophilic substitution with allyltrimethylsilane(ATMS)at approximately 40%monomer conversion.The experimental results indicate that the substitution efficiency of ATMS increased with higher ATMS concentration,temperature,and extended reaction time.Nearly unity ally-functionality for allyl-PSTO-allyl was achieved by adding sufficient SnCl_(4) prior to the substitution.
基金financially supported by the National Key R&D Program of China(No.2021YFA1501700)the National Natural Science Foundation of China(Nos.22371194 and 22301197)Fundamental Research Funds from Sichuan University(Nos.2023SCUNL103 and 2024SCUQJTX005)。
文摘Chemically recyclable polythioesters are of particular interest owing to their unique properties and desired sustainability.By the exploit of a benzo-fusion strategy toε-thiocaprolactone,we successfully improved the chemical recyclability and regulated the thermal and mechanical properties of the resulting polythioesters.The efficient ring-opening polymerization(ROP)of benzo-fused thiolactone monomers(M)containing different substituents gave rise to high-molecular-weight semi-aromatic polythioesters P(M)s.The resulting P(M)s showcased tunable physical and mechanical properties.The debenzylation of P(M3)was able to generate P(M3-OH)with free hydroxyl sidechains.Notably,chemical recycling of the resulting P(M)s back to their corresponding monomers via bulk thermal depolymerization achieved high efficiency(>95%yield,99%purity),establishing a closed-loop lifecycle.
基金supported by the National Natural Science Foundation of China(No.U23B6011)the Jilin Provincial Science and Technology Department Program(No.20230101347JC)。
文摘Mechanochromic polyolefins represent a novel class of functionalized polyolefins,which still remains significant challenges.Pd(II)-catalyzed coordination-insertion copolymerization is a feasible method for achieving this kind of polymers,yet with linear microstructures.Ringopening metathesis polymerization(ROMP)offers another promising avenue for affording functionalized polyolefins.This method exhibits high polar group tolerance and the ability to precisely regulate polymer branches.In this study,we report the method for producing mechanochromic branched polyethylenes via ROMP.By employing the terpolymerization of a well-designed monomer containing the mechanochromic group,NB-ABF,with cyclooctene(COE)and long-chain 5-hexylcyclooctene(COE-C6),following by hydrogenation process,we synthesized a range of functionalized branched polyethylenes characterized by varied branching density and polar monomer incorporation.These polymers bear a structural resemblance to functionalized ethylene-octene copolymers.After crosslinking,mechanochromophores are generated,and mechanochromism is achieved in uniaxial tensile testing.A comprehensive assessment reveals that both the incorporation of polar monomers and variations in branching density significantly influence their mechanical properties.Notably,upon stretching,these materials display pronounced visible color change,confirming the successful development of mechanochromic branched polyethylenes.
基金financially supported by the National Natural Science Foundation of China(52162036 and 22378342)Key Project of Nature Science Foundation of Xinjiang(2021D01D08)+2 种基金Major Projects of Xinjiang(2022A01005-4 and 2021A01001-1)Key Research and Development Project of Xinjiang(2023B01025-1)the support from the Doctoral Student Special Program of the Young Talents Support Project of the China Association for Science and Technology in 2024。
文摘Practical Zn metal batteries have been hindered by several challenges,including Zn dendrite growth,undesirable side reactions,and unstable electrode/electrolyte interface.These issues are particularly more serious in low-concentration electrolytes.Herein,we design a Zn salt-mediated electrolyte with in situ ring-opening polymerization of the small molecule organic solvent.The Zn(TFSI)_(2)salt catalyzes the ring-opening polymerization of(1,3-dioxolane(DOL)),generating oxidation-resistant and non-combustible long-chain polymer(poly(1,3-dioxolane)(pDOL)).The pDOL reduces the active H_(2)O molecules in electrolyte and assists in forming stable organic–inorganic gradient solid electrolyte interphase with rich organic constituents,ZnO and ZnF_(2).The introduction of pDOL endows the electrolyte with several advantages:excellent Zn dendrite inhibition,improved corrosion resistance,widened electrochemical window(2.6 V),and enhanced low-temperature performance(freezing point=-34.9°C).Zn plating/stripping in pDOL-enhanced electrolyte lasts for 4200 cycles at 99.02%Coulomb efficiency and maintains a lifetime of 8200 h.Moreover,Zn metal anodes deliver stable cycling for 2500 h with a high Zn utilization of 60%.A Zn//VO_(2)pouch cell assembled with lean electrolyte(electrolyte/capacity(E/C=41 mL(Ah)^(-1))also demonstrates a capacity retention ratio of 92%after 600 cycles.These results highlight the promising application prospects of practical Zn metal batteries enabled by the Zn(TFSI)2-mediated electrolyte engineering.
基金supported by the National Natural Science Foundation of China,Fund for Distinguished Young Scholars(No.52325301)CAS Project for Young Scientists in Basic Research(YSBR-094)the National Natural Science Foundation of China,Basic Science Center Program(No.51988102).
文摘Aliphatic polyesters and polycarbonates are among the promising sustainable polymers,which exhibit unique degradability and chain-chain interactions owing to their heterofunctionality.However,monocomponent aliphatic polyesters and polycarbonates usually suffer from inferior properties and functionalities.By contrast,precisely modulated block copolymers composed of polyesters and polycarbonates give rise to sustainable materials with tailored performance.An efficient approach to synthesize the block copolymers is the ring-opening(co)polymerization of the heterocycle monomers.Herein,this review presents the heterocycle monomer ring-opening(co)polymerization for the formation of sequence-controlled block polyesters and polycarbonates.Available synthetic strategies,different monomers,monomer combinations and the catalyst systems for the formation of different block polyesters and polycarbonates are summarized.
基金supported by National Natural Science Foundation of China(Nos.21271092,21171078,and 21401161)the Science Foundation of Gansu Province of China(No.1308RJ2A121)
文摘A series of bis-ligated zinc complexes supported by Schitt base ligands were successfully synthesized and characterized by 1 H, 13C NMR, elemental analysis, and X-ray crystallography. These zinc complexes can be used as catalysts for the polymerization of rac-lactide in solution as well as in molten lactide. The results show that all catalysts exhibited high catalytic activity and obtained moderate heterotactic PLAs with the expected molecular weight. Complex 1 can catalyze the polymerization of rac-lactide under controllable conditions with living and immortal character in toluene solution. In addition, the steric hindrance and electronic effects has a great influence on the catalytic activity and selectivity of catalysts.
基金financially supported by National Key R&D Program Young Scientists Project(No.2023YFC3903100)the National Natural Science Foundation of China(No.22322503)analytical and testing assistance from the Analysis and Testing Center of HUST。
文摘Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.
基金supported by the Basic Science Research Program(RS-2024-00344021,RS-2023-00261543,and RS-202300257666)through the National Research Foundation of Korea(NRF),the National Research Council of Science(000)Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(RS-2024-00420590,HRD Program for Industrial Innovation)The computational resources were provided by KITSI(KSC-2024-CRE-0143)。
文摘Despite the growing interest in fast-cha rging solid-state lithium(Li)-metal batteries(SSLMBs),their practical implementation has yet to be achieved,primarily due to an incomplete understanding of the disparate and often conflicting requirements of the bulk electrolyte and the electrode-electrolyte interphase.Here,we present a weakly coordinating cationic polymer electrolyte(WCPE)specifically designed to regulate the Li^(+)coordination structure,thereby enabling fast-charging SSLMBs.The WCPE comprises an imidazolium-based polycationic matrix combined with a succinonitrile(SN)-based highconcentration electrolyte.Unlike conventional neutral polymer matrices,the polycationic matrix in the WCPE competes with Li^(+)for interactions with SN,weakening the original coordination between SN and Li^(+).This modulation of SN-Li^(+)interaction improves both Li^(+)conductivity of the WCPE(σ_(Li^(+))=1.29mS cm^(-1))and redox kinetics at the electrode-electrolyte interphase.Consequently,SSLMB cells(comprising LiFePO_(4)cathodes and Li-metal anodes)with the WCPE achieve fast-charging capability(reaching over 80%state of charge within 10 min),outperforming those of previously reported polymer electrolytebased SSLMBs.
基金financially supported by the National Natural Science Foundation of China(No.20934001)
文摘A novel simple but effective initiating system of H2O/AlCl3/veratrole （VE） has been developed to synthesize high molecular weight polyisobutylene （PIB） at elevated temperatures via cationic polymerization of isobutylene （IB） in solvent mixture of hexane/methylene dichloride （n-Hex/CH2Cl2 = 2/1, V/V）. VE played very important roles in decreasing cationicity of the growing chain ends, suppressing side reactions of chain transfer and termination during polymerization, leading to production of high molecular weight PIBs. PIBs with high yields, having very high weight-average molecular weight （Mw） of 1117000 and 370000 g/tool could be synthesized with H2O/AICl3/VE initiating system at VE concentration of 5.4 mmol/L at -80 and -60 ℃ respectively. Molecular weight of PIB increased remarkably with increasing VE concentration. The reaction order with respect to VE concentration was determined to be -3.52 via FTIR spectroscopy in combination with a diamond tipped attenuated total reflectance （ATR） immersion probe. The negative reaction order of VE was consistent with its retarding effect on IB polymerization by interacting with the propagating species. Molecular weight of PIB decreased with increasing polymerization temperature. The activation energy for polymerization degree （Eop） could be determined to be around -23 kJ/mol when VE concentration was 5.4 mmol/L or 6.4 mmol/L.
基金supported by the National Natural Science Foundation of China(Nos.20774008,20934001) and SINOPEC
文摘The cationic polymerizations of isobutylene （IB） coinitiated by AlCl3 were carried out in solvent mixture of nhexane/methylene dichloride （n-hex/CH2Cl2） of 60/40 V/V in the presence of ethyl benzoate （EB） at various temperatures range from -80℃ to -30℃. The effects of EB concentration （[EB]） and polymerization temperature on monomer conversion, weight-average molecular weight （Mw） and molecular weight distribution （MWD, Mw/Mn） of polyisobutylene （PIB） products were investigated. The rate of polymerization decreased while Mw of PIB products increased with increasing [EB]. The polymers with high molecular weight could be prepared in the presence of a suitable amount of EB. Significantly, the polymers with high Mw of 80.2 × 10^4 and 65.4 × 10^4 could be produced at -80℃ and -70℃ at [EB] = 0.24 × 10^3 mol/L respectively, which were much higher than that （Mw = 57.9 × 10^4） of PIB prepared at -100℃ in the absence ofEB. A simple but effective method for preparing the high molecular weight polyisobutylenes was developed in this work. It has been also found that the activation energy for propagation （Ep） depended on the polymerization temperature range in the presence of EB. An obvious inflection of the linear plots of lnXn versus 1/Tp occurred at the temperature range from -60℃ to -50℃ at four different concentrations of EB from 0.19 × 10^3 mol/L to 0.33× 10^3 tool/L, and thus the inflection temperature （Tinf） was in the range of -60℃ to -50℃. When [EB] was in the range of 0.24 × 10^3 mol/L to 0.33× 10^3 mol/L, Ep was determined to be around -12 kJ/mol when the polymerization was carried out at temperatures from -80℃ to Tinf and to be around -28 kJ/mol at temperatures from Tinf to -15℃ respectively.
基金Supported by the National Natural Science Foundation of China （No.20576117）
文摘Cationic ring opening polymerization of octamethylcyclotetrasiloxane （Da） initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary experiments.Higher temperature was found beneficial for the reaction process while stirring intensity beyond a certain level showed no obvious effect on the reaction rate. Polymers were characterized by Fourier transform infrared, proton nuclear magnetic resonance （IH-NMR） and gel perneation chromotography. The width of molecular mass distribution was found ranging between 1.2 and 1.4, which is extraordinarlly narrow compared with that of cationic polymerizations reported elsewhere （〉 1.9）. The results were believed due to the absence of free proton and counter ion which simplifies the polymerization process and the huge steric hindrance provided by bentonite particles which keeps the propagation of polysiloxane onto the surface of bentonite particles in a much more regular way. A feasible mechanism is proposed and seems to be supported well by experiments. Additionally, from the results of α, ω-dihydrogen terminated polysiloxanes prepared, the possibility of applying this potential environmentally friendly heterogeneous catalyst in industrial polymerization of cyclosiloxanes is anticipated.
基金financially supported by the National Natural Science Foundation of China (No. 21871232)the Zhejiang Provincial Natural Science Foundation of China (No. LR15B040001)
文摘Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxide, three stages are identified by kinetic study including(1) fast cationic polymerization with slow anionic one,(2) fast anionic polymerization with dormant cationic one, and(3)reactivation of cationic polymerization with coupling of anionic and cationic chain ends. In this work, density functional theory(DFT)calculation is employed to investigate the reaction details of ionic polymerization and dormancy. A “tripedal crow” configuration is proposed to illustrate the unique high-coordinated ligand exchange configuration in anionic polymerization in different stages. The trigger of dormancy is determined as chain structures rather than concentration of triflate anion according to both calculation and experimental results.
基金financially supported by the National Natural Science Foundation of China (Nos. 21734004 and 21674038)
文摘Highly potent ionic organocatalyst is developed for room-temperature controlled ring-opening polymerization(ROP)of lactones,includingδ-valerolactone,ε-caprolactone,andδ-hexalactone.The catalysts are prepared by simply mixing tetra-n-butyl ammonium hydroxide and a(thio)urea at elevated temperature under vacuum,and used in cooperation with an alcoholic initiator.The performance of the catalyst is readily adjusted and optimized through variation of the(thio)urea precursor,catalyst composition,and reaction condition.Urea-derived catalysts are generally superior to thiourea-derived ones.Provided with proper N-substituents,the catalyst affords both high polymerization efficiency and high selectivity for monomer enchainment over macromolecular transesterification,even at high monomer conversion and/or substantially extended reaction time.In addition to acidity,structural symmetry of the urea also proves decisive for the catalytic activity,which enables a catalyst-assisted proton transfer process for the ring-opening of lactone and thus provides a novel mechanistic insight for ROP catalyzed by hydrogen-bonding type bifunctional ionic organocatalysts.
