光诱导电子转移可逆加成-断裂链转移聚合(Photoinduced Electron Transfer-Reversible Addition Fragmentation Chain Transfer Polymerization,PET-RAFT聚合,凭借能耗低、反应条件温和、时空可控、反应正交性和耐氧性等特性在聚合领域...光诱导电子转移可逆加成-断裂链转移聚合(Photoinduced Electron Transfer-Reversible Addition Fragmentation Chain Transfer Polymerization,PET-RAFT聚合,凭借能耗低、反应条件温和、时空可控、反应正交性和耐氧性等特性在聚合领域得到广泛关注与应用,在表面改性方面,PET-RAFT聚合被用于改善材料的表面特性,如生物相容性和抗黏附性。在生物医药领域,PET-RAFT聚合技术用于药物递送系统,如球形胶束和囊泡。此外,PET-RAFT聚合在3D打印和激光写入中的应用展示了其在精确控制材料结构和功能化方面的巨大潜力。PET-RAFT聚合的关键在于寻找合适的光催化剂,目前催化剂包括均相和非均相催化剂体系,均相催化体系如过渡金属络合物、卟啉及酞菁类催化剂、有机染料和半导体材料等,非均相催化剂体系如宏观材料负载型、纳米材料负载型、金属有机框架型、共价有机框架型和共轭微孔聚合物等,其中非均相催化剂可以通过离心和过滤分离对光催化剂进行有效回收利用。未来研究者将开发新型低成本、高效率、易回收、无毒的光催化剂以提高低能光子的使用效率和改善光聚合与环境的相容性。展开更多
To achieve the target of carbon neutrality,it is crucial to develop an efficient and green synthesis methodology with good atomic economy to achieve sufficient utilization of energy and sustainable development.Photoin...To achieve the target of carbon neutrality,it is crucial to develop an efficient and green synthesis methodology with good atomic economy to achieve sufficient utilization of energy and sustainable development.Photoinduced electron transfer reversible addition-fragmentation chain-transfer(PET-RAFT)polymerization is a precise methodology for constructing polymers with well-defined structures.However,conventional semiconductor-mediated PET-RAFT polymerization still has considerable limitations in terms of efficiency as well as the polymerization environment.Herein,sulfur-doped carbonized polymer dots(CPDs)were hydrothermally synthesized for catalysis of aqueous PET-RAFT polymerization at unprecedented efficiency with a highest propagation rate of 5.05 h-1.The resulting polymers have well-controlled molecular weight and narrow molecular weight dispersion(Ð<1.10).Based on the optoelectronic characterizations,we obtained insights into the photoinduced electron transfer process and proposed the mechanism for CPD-mediated PET-RAFT polymerization.In addition,as-synthesized CPDs for PET-RAFT polymerization were also demonstrated to be suitable for a wide range of light sources(blue/green/solar irradiation),numerous monomers,low catalyst loading(low as 0.01 mg mL^(-1)),and multiple polar solvent environments,all of which allowed to achieve efficiencies much higher than those of existing semiconductor-mediated methods.Finally,the CPDs were confirmed to be non-cytotoxic and catalyzed PET-RAFT polymerization successfully in cell culture media,indicating broad prospects in biomedical fields.展开更多
Phenanthroline is an excellent and stableπ-electron acceptor with a large conjugated chromophore.Phenanthroline derivatives are widely used in adsorption,photodegradation,solar cells,biology,and so on.At present,ther...Phenanthroline is an excellent and stableπ-electron acceptor with a large conjugated chromophore.Phenanthroline derivatives are widely used in adsorption,photodegradation,solar cells,biology,and so on.At present,there are still limited organic molecules utilized to efficiently photocatalyze reversible-deactivation radical polymerization(RDRP).Therefore,the design of organic photocatalysts(OPCs)for RDRP remains a challenge.Herein,according to the strategy of combining the donor groups and weak acceptor groups,donor-acceptor(D-A)type OPCs based on phenanthroline were utilized for the first time in photoinduced electron transfer-reversible addition-fragmentation chain transfer(PET-RAFT)polymerization.1,10-Phenanthroline-5-amine(Aphen)with a donor group-amino was screened out for efficacious photo-controlled radical polymerization under blue light for various monomers with conjugated and unconjugated structures with high monomer conversion and well-defined narrow dispersity polymers(Đ<1.20).Controllable homo-polymers and block copolymers were successfully realized by chain extension reaction and block copolymerization of structurally diverse monomers.展开更多
Bottle-brush polymers possessing densely grafted side chains have special properties that are distinct from linear macromolecules.Herein,an efficient method for preparing bottle-brush polymers based on a selective pho...Bottle-brush polymers possessing densely grafted side chains have special properties that are distinct from linear macromolecules.Herein,an efficient method for preparing bottle-brush polymers based on a selective photoactivation strategy in the photoinduced electron/energy transfer reversible addition-fragmentation chain transfer(PET-RAFT)polymerization was developed.A methacrylate monomer 2-(2-(dodecylthiocarbonothioylthio)propionate)ethyl methacrylate(DTPEMA)containing a 2-(dodecylthiocarbonothioylthio)propionate(DTP)unit with a secondary R group was designed.Utilizing the unique selectivity of metal naphthalocyanine photocatalyst zinc 2,11,20,29-tetra-tert-butyl-2,3-naphthalocyanine(ZnTtBNc)toward trithiocarbonate with tertiary R group,the PET-RAFT polymerization of DTPEMA catalyzed by ZnTtBNc was performed under near infrared(NIR)light(λ_(max)=760 nm)irradiation at room temperature,using 4-cyano-4-[(dodecylsulfanylthiocarbonyl)-sulfanyl]pentanoic acid(CDTPA)with a tertiary R group as a chain transfer agent(CTA).Proton nuclear magnetic resonance(1H NMR)and gel permeation chromatography(GPC)results demonstrated that the DTP units in the side chains were inert during the polymerization.By grafting poly(methyl acrylate)(PMA)from PDTPEMA via thermal-initiated RAFT polymerization,welldefined P(DTPEMA-g-PMA)bottle-brush polymers could be afforded.Furthermore,the film prepared from the bottle-brush polymer exhibited excellent scratch self-healing property due to the interlocking of side chains.展开更多
Polymerization-induced self-assembly(PISA)combines synthesis and self-assembly of artificial polymers in one-pot,which brings us one step closer to emulating biosynthesis.However,the reported PISA formulations primari...Polymerization-induced self-assembly(PISA)combines synthesis and self-assembly of artificial polymers in one-pot,which brings us one step closer to emulating biosynthesis.However,the reported PISA formulations primarily focus on developing nano-objects with new chemical compositions and rarely on structural regulation of polymers with specific components.Herein,sequence structure controllable polymerization-induced self-assembly(SCPISA)is reported by using 7-(2-methacryloyloxyethoxy)-4-methylcoumarin(CMA)as a monomer.During the copolymerization of 2-hydroxyethyl methacrylate(HEMA)and CMA,controlled incorporation of CMA units into the polymer chains can be realized by programmable light/heat changes.SCPISA-based P(HEMA-co-CMA)copolymers with the same composition but different sequence structures generate a range of assemblies.Moreover,the morphologies of the resultant nano-objects can also be controlled by regulating the feed molar ratio of CMA and HEMA,which is similar to the conventional PISA,but the synthesis procedure is obviously simplified in SCPISA.The versatility of the methodology is further demonstrated by the fabrication of different functional nano-objects with sequence structure-dependent morphologies in SCPISA systems with different functional monomers.展开更多
Despite the challenges that remain,the synergistic adjustment of various microstructures and photochemical parameters of graphitic carbon nitride(g-C_(3)N_(4))in photocatalytic reactions holds promises for improving c...Despite the challenges that remain,the synergistic adjustment of various microstructures and photochemical parameters of graphitic carbon nitride(g-C_(3)N_(4))in photocatalytic reactions holds promises for improving catalytic efficiency and reducing energy consumption.Herein,sulfur-doped and nitrogen-defective g-C_(3)N_(4)(n-SC_(3)N_(x))nanosheets were designed and elaborately synthesized.The resultant n-SC_(3)N_(x)possessed a precisely defined 2D layer structure with extensive porosity and incremental specific surface area.Enhanced photoinduced electron transfer-reversible addition-fragmentation chain transfer(PET-RAFT)polymerization of vinyl monomers with low dispersity,excellent temporal control and high chain-end fidelity was achieved under mild blue light irradiation in a nondegassed system.Owing to their ultrathin nanostructures with nitrogen defects and sulfur dopants,n-SC_(3)N_(x)was capable of catalyzing RAFT polymerization in aqueous solutions at significantly accelerated rates,which were nearly 8 times faster compared to bulk g-C_(3)N_(4).The ease of separation and efficient reusability in subsequent polymerizations was enabled by the heterogeneous nature of n-SC_(3)N_(x).The appeal of this approach was illustrated by the fact that utilizing a reusable and metal-free photocatalyst in aqueous environments allowed for the synthesis of polymers with molecular weight up to 300 kg mol^(-1) and a dispersity of 1.32.展开更多
Developing a new type of photocatalyst(PC) and catalytic mechanism for near-infrared(NIR) photocontrolled reversibledeactivation radical polymerization(RDRP) system is charming but challenging.Herein,a novel PC of the...Developing a new type of photocatalyst(PC) and catalytic mechanism for near-infrared(NIR) photocontrolled reversibledeactivation radical polymerization(RDRP) system is charming but challenging.Herein,a novel PC of the persistent radical anion(PRA)(possessing the properties of both radical and anion) was developed for NIR photocontrolled reversible additionfragmentation chain transfer(RAFT) polymerization,enabling successful polymerization while gaining a deep insight into the mechanism of photo-induced electron transfer RAFT(PET-RAFT) polymerization.Different from the conventional and wellaccepted reductive quenching(RQ) pathway,in which the radical anion intermediates of PCs(PCs^(·-)) must be generated in an excited state(ES),here,the PRA(3,4,9,10-perylenetetracarboxylic dianhydride radical anion(PTCDA^(·-))) could generate conveniently in situ in the ground state(GS) and subsequently serve as highly efficient PC in the NIR region(740–850 nm).The successful implementation of this strategy elucidates the peculiar role played by light and the real way of electron transfer behaviors.In fact,the transfer of a single electron from PRA to chain transfer agent(CTA) and cleavage of the C–S bonds is a process from ES to GS,rather than always from GS(PCs^(·-)) to GS(CTA) in the RQ pathway as is well known to all.In addition,the excellent spatial-temporal control and powerful penetration ability of the NIR light were also confirmed by this PRAcatalyzed polymerization system.展开更多
Auto-tandem catalysis that uses a single catalyst to bridge and discriminate different catalytic cycles in a one-pot process is highly desirable for obtaining a high degree of structural complexity;however,it is a gre...Auto-tandem catalysis that uses a single catalyst to bridge and discriminate different catalytic cycles in a one-pot process is highly desirable for obtaining a high degree of structural complexity;however,it is a great challenge to develop auto-tandem catalytic systems in polymer chemistry.Herein,we report the auto-tandem catalysis by rationally designed aluminum porphyrin complexes,wherein well-controlled photoinduced electron/energy transfer–reversible addition-fragmentation chain transfer(PET-RAFT)polymerization of vinyl monomers and completely alternating ring-opening copolymerization(ROCOP)of epoxides/anhydrides can occur in a concurrent or sequential manner.With a carboxylic group incorporated trithiocarbonate compound bearing a carboxylic acid group(TTC-COOH)as the bifunctional chain transfer agent(CTA),the auto-tandem catalysis provides one-pot access to diblock copolymers with predictable molecular weights and narrow distributions.Notably,the efficient electron/energy transfer from 5,10,15,20-tetrakis(2-chlorophenyl)porphyrin aluminum(III)chloride[(TPP^(2-Cl))Al^(III)-Cl]to TTC-COOH and their axial group exchange reactions completely circumvent the formations of undesirable homopolymers.展开更多
文摘光诱导电子转移可逆加成-断裂链转移聚合(Photoinduced Electron Transfer-Reversible Addition Fragmentation Chain Transfer Polymerization,PET-RAFT聚合,凭借能耗低、反应条件温和、时空可控、反应正交性和耐氧性等特性在聚合领域得到广泛关注与应用,在表面改性方面,PET-RAFT聚合被用于改善材料的表面特性,如生物相容性和抗黏附性。在生物医药领域,PET-RAFT聚合技术用于药物递送系统,如球形胶束和囊泡。此外,PET-RAFT聚合在3D打印和激光写入中的应用展示了其在精确控制材料结构和功能化方面的巨大潜力。PET-RAFT聚合的关键在于寻找合适的光催化剂,目前催化剂包括均相和非均相催化剂体系,均相催化体系如过渡金属络合物、卟啉及酞菁类催化剂、有机染料和半导体材料等,非均相催化剂体系如宏观材料负载型、纳米材料负载型、金属有机框架型、共价有机框架型和共轭微孔聚合物等,其中非均相催化剂可以通过离心和过滤分离对光催化剂进行有效回收利用。未来研究者将开发新型低成本、高效率、易回收、无毒的光催化剂以提高低能光子的使用效率和改善光聚合与环境的相容性。
基金supported by the National Natural Science Foundation of China(NSFC)under Grant No.22035001 and No.52233005.
文摘To achieve the target of carbon neutrality,it is crucial to develop an efficient and green synthesis methodology with good atomic economy to achieve sufficient utilization of energy and sustainable development.Photoinduced electron transfer reversible addition-fragmentation chain-transfer(PET-RAFT)polymerization is a precise methodology for constructing polymers with well-defined structures.However,conventional semiconductor-mediated PET-RAFT polymerization still has considerable limitations in terms of efficiency as well as the polymerization environment.Herein,sulfur-doped carbonized polymer dots(CPDs)were hydrothermally synthesized for catalysis of aqueous PET-RAFT polymerization at unprecedented efficiency with a highest propagation rate of 5.05 h-1.The resulting polymers have well-controlled molecular weight and narrow molecular weight dispersion(Ð<1.10).Based on the optoelectronic characterizations,we obtained insights into the photoinduced electron transfer process and proposed the mechanism for CPD-mediated PET-RAFT polymerization.In addition,as-synthesized CPDs for PET-RAFT polymerization were also demonstrated to be suitable for a wide range of light sources(blue/green/solar irradiation),numerous monomers,low catalyst loading(low as 0.01 mg mL^(-1)),and multiple polar solvent environments,all of which allowed to achieve efficiencies much higher than those of existing semiconductor-mediated methods.Finally,the CPDs were confirmed to be non-cytotoxic and catalyzed PET-RAFT polymerization successfully in cell culture media,indicating broad prospects in biomedical fields.
基金We would like to appreciate the financial support of the National Natural Science Foundation of China(No.22271044)Jilin Provincial Science and Technology Development Foundation(No.20210101404JC).
文摘Phenanthroline is an excellent and stableπ-electron acceptor with a large conjugated chromophore.Phenanthroline derivatives are widely used in adsorption,photodegradation,solar cells,biology,and so on.At present,there are still limited organic molecules utilized to efficiently photocatalyze reversible-deactivation radical polymerization(RDRP).Therefore,the design of organic photocatalysts(OPCs)for RDRP remains a challenge.Herein,according to the strategy of combining the donor groups and weak acceptor groups,donor-acceptor(D-A)type OPCs based on phenanthroline were utilized for the first time in photoinduced electron transfer-reversible addition-fragmentation chain transfer(PET-RAFT)polymerization.1,10-Phenanthroline-5-amine(Aphen)with a donor group-amino was screened out for efficacious photo-controlled radical polymerization under blue light for various monomers with conjugated and unconjugated structures with high monomer conversion and well-defined narrow dispersity polymers(Đ<1.20).Controllable homo-polymers and block copolymers were successfully realized by chain extension reaction and block copolymerization of structurally diverse monomers.
基金supported by the National Natural Science Foundation of China(22201276,22131010,52021002)。
文摘Bottle-brush polymers possessing densely grafted side chains have special properties that are distinct from linear macromolecules.Herein,an efficient method for preparing bottle-brush polymers based on a selective photoactivation strategy in the photoinduced electron/energy transfer reversible addition-fragmentation chain transfer(PET-RAFT)polymerization was developed.A methacrylate monomer 2-(2-(dodecylthiocarbonothioylthio)propionate)ethyl methacrylate(DTPEMA)containing a 2-(dodecylthiocarbonothioylthio)propionate(DTP)unit with a secondary R group was designed.Utilizing the unique selectivity of metal naphthalocyanine photocatalyst zinc 2,11,20,29-tetra-tert-butyl-2,3-naphthalocyanine(ZnTtBNc)toward trithiocarbonate with tertiary R group,the PET-RAFT polymerization of DTPEMA catalyzed by ZnTtBNc was performed under near infrared(NIR)light(λ_(max)=760 nm)irradiation at room temperature,using 4-cyano-4-[(dodecylsulfanylthiocarbonyl)-sulfanyl]pentanoic acid(CDTPA)with a tertiary R group as a chain transfer agent(CTA).Proton nuclear magnetic resonance(1H NMR)and gel permeation chromatography(GPC)results demonstrated that the DTP units in the side chains were inert during the polymerization.By grafting poly(methyl acrylate)(PMA)from PDTPEMA via thermal-initiated RAFT polymerization,welldefined P(DTPEMA-g-PMA)bottle-brush polymers could be afforded.Furthermore,the film prepared from the bottle-brush polymer exhibited excellent scratch self-healing property due to the interlocking of side chains.
基金supported by the National Natural Science Foundation of China(22171255,22131010,52021002)。
文摘Polymerization-induced self-assembly(PISA)combines synthesis and self-assembly of artificial polymers in one-pot,which brings us one step closer to emulating biosynthesis.However,the reported PISA formulations primarily focus on developing nano-objects with new chemical compositions and rarely on structural regulation of polymers with specific components.Herein,sequence structure controllable polymerization-induced self-assembly(SCPISA)is reported by using 7-(2-methacryloyloxyethoxy)-4-methylcoumarin(CMA)as a monomer.During the copolymerization of 2-hydroxyethyl methacrylate(HEMA)and CMA,controlled incorporation of CMA units into the polymer chains can be realized by programmable light/heat changes.SCPISA-based P(HEMA-co-CMA)copolymers with the same composition but different sequence structures generate a range of assemblies.Moreover,the morphologies of the resultant nano-objects can also be controlled by regulating the feed molar ratio of CMA and HEMA,which is similar to the conventional PISA,but the synthesis procedure is obviously simplified in SCPISA.The versatility of the methodology is further demonstrated by the fabrication of different functional nano-objects with sequence structure-dependent morphologies in SCPISA systems with different functional monomers.
基金supported by the National Natural Science Foundation of China(51773156)the Shenzhen Science and Technology Program(JCYJ20220530140607016)。
文摘Despite the challenges that remain,the synergistic adjustment of various microstructures and photochemical parameters of graphitic carbon nitride(g-C_(3)N_(4))in photocatalytic reactions holds promises for improving catalytic efficiency and reducing energy consumption.Herein,sulfur-doped and nitrogen-defective g-C_(3)N_(4)(n-SC_(3)N_(x))nanosheets were designed and elaborately synthesized.The resultant n-SC_(3)N_(x)possessed a precisely defined 2D layer structure with extensive porosity and incremental specific surface area.Enhanced photoinduced electron transfer-reversible addition-fragmentation chain transfer(PET-RAFT)polymerization of vinyl monomers with low dispersity,excellent temporal control and high chain-end fidelity was achieved under mild blue light irradiation in a nondegassed system.Owing to their ultrathin nanostructures with nitrogen defects and sulfur dopants,n-SC_(3)N_(x)was capable of catalyzing RAFT polymerization in aqueous solutions at significantly accelerated rates,which were nearly 8 times faster compared to bulk g-C_(3)N_(4).The ease of separation and efficient reusability in subsequent polymerizations was enabled by the heterogeneous nature of n-SC_(3)N_(x).The appeal of this approach was illustrated by the fact that utilizing a reusable and metal-free photocatalyst in aqueous environments allowed for the synthesis of polymers with molecular weight up to 300 kg mol^(-1) and a dispersity of 1.32.
基金supported by the National Natural Science Foundation of China (21871201)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)。
文摘Developing a new type of photocatalyst(PC) and catalytic mechanism for near-infrared(NIR) photocontrolled reversibledeactivation radical polymerization(RDRP) system is charming but challenging.Herein,a novel PC of the persistent radical anion(PRA)(possessing the properties of both radical and anion) was developed for NIR photocontrolled reversible additionfragmentation chain transfer(RAFT) polymerization,enabling successful polymerization while gaining a deep insight into the mechanism of photo-induced electron transfer RAFT(PET-RAFT) polymerization.Different from the conventional and wellaccepted reductive quenching(RQ) pathway,in which the radical anion intermediates of PCs(PCs^(·-)) must be generated in an excited state(ES),here,the PRA(3,4,9,10-perylenetetracarboxylic dianhydride radical anion(PTCDA^(·-))) could generate conveniently in situ in the ground state(GS) and subsequently serve as highly efficient PC in the NIR region(740–850 nm).The successful implementation of this strategy elucidates the peculiar role played by light and the real way of electron transfer behaviors.In fact,the transfer of a single electron from PRA to chain transfer agent(CTA) and cleavage of the C–S bonds is a process from ES to GS,rather than always from GS(PCs^(·-)) to GS(CTA) in the RQ pathway as is well known to all.In addition,the excellent spatial-temporal control and powerful penetration ability of the NIR light were also confirmed by this PRAcatalyzed polymerization system.
基金Financial support from National Key R&D Plan(no.2016YFB0302400)NSFC(no.21604027)of Chinathe Fundamental Research Funds for the Central Universities(HUST:2019JYCXJJ015).
文摘Auto-tandem catalysis that uses a single catalyst to bridge and discriminate different catalytic cycles in a one-pot process is highly desirable for obtaining a high degree of structural complexity;however,it is a great challenge to develop auto-tandem catalytic systems in polymer chemistry.Herein,we report the auto-tandem catalysis by rationally designed aluminum porphyrin complexes,wherein well-controlled photoinduced electron/energy transfer–reversible addition-fragmentation chain transfer(PET-RAFT)polymerization of vinyl monomers and completely alternating ring-opening copolymerization(ROCOP)of epoxides/anhydrides can occur in a concurrent or sequential manner.With a carboxylic group incorporated trithiocarbonate compound bearing a carboxylic acid group(TTC-COOH)as the bifunctional chain transfer agent(CTA),the auto-tandem catalysis provides one-pot access to diblock copolymers with predictable molecular weights and narrow distributions.Notably,the efficient electron/energy transfer from 5,10,15,20-tetrakis(2-chlorophenyl)porphyrin aluminum(III)chloride[(TPP^(2-Cl))Al^(III)-Cl]to TTC-COOH and their axial group exchange reactions completely circumvent the formations of undesirable homopolymers.
