阅读说明：本技术 一种基于氧杂芳环类光催化剂的高活性自由基聚合体系 (High-activity free radical polymerization system based on oxygen-heterocyclic photocatalyst ) 是由 廖赛虎 马强 于 2020-05-25 设计创作，主要内容包括：本发明公开了一种活性自由基聚合体系,该体系包含氧杂芳环类化合物光催化剂或光敏剂,有机卤化物或硫化物引发试剂。该体系简单,高效,易操作,重复性好,可选用光源波长范围宽,适用于多种类型烯烃类单体的可控自由基聚合。在温和条件下,可以实现了甲基丙烯酸甲酯,甲基丙烯酸苄基酯,甲基丙烯酸丁酯,丙烯酸丁酯,N,N-二甲基丙烯酰胺,醋酸乙烯酯,N-(2-羟丙基)甲基丙烯酰胺,N-乙烯基吡咯烷酮,2,2,2-甲基丙烯酸三氟乙基酯和苯乙烯等单体的活性自由基聚合,并得到良好的控制。该类氧杂芳环类光催化剂与传统含氮杂环类光催化剂相比,具有超高催化活性,并且是目前已知的最高活性。(The invention discloses a living radical polymerization system, which comprises an oxygen-heterocyclic aromatic compound photocatalyst or photosensitizer and an organic halide or sulfide initiating reagent. The system is simple, efficient, easy to operate, good in repeatability, wide in wavelength range of the selectable light source and suitable for controllable free radical polymerization of various olefin monomers. Under mild conditions, the living radical polymerization of monomers such as methyl methacrylate, benzyl methacrylate, butyl acrylate, N, N-dimethylacrylamide, vinyl acetate, N- (2-hydroxypropyl) methacrylamide, N-vinyl pyrrolidone, trifluoroethyl 2,2, 2-methacrylate and styrene can be realized and well controlled. Compared with the traditional nitrogen heterocyclic ring photocatalyst, the oxygen heterocyclic ring photocatalyst has ultrahigh catalytic activity and is the highest activity known at present.)

1. A high activity free radical polymerization system based on an oxaaromatic ring photocatalyst is characterized in that: the polymerization system comprises a monomer, a photocatalyst and an initiator; the photocatalyst is a dioxaanthanthanthrene compound, and the initiator is an organic halide or sulfide; the structure of the photocatalyst is shown as formula I:

in the formula I, the compound is shown in the specification,

R₁、R₂、R₃、R₄、R₅、R₁’、R₂’、R₃’、R₄', and R₅' is independently selected from hydrogen, halogen, cyano, C₁～C₂₄Alkyl, C substituted by one or more halogens₁～C₂₄Alkyl radical, C₁～C₂₄Alkoxy radical, C₁～C₂₄Alkyl O (C ═ O) -, C₁～C₂₄Alkyl (C ═ O) O-, C₁～C₂₄Alkyl (C ═ O) -, C₁～C₂₄Alkyl (C ═ O) NH —, [ C ═ O)₁～C₂₄Alkyl (C ═ O)]₂N-、R^1-1R^1-2R^1-3Si-, by one or more R^1-4Substituted C₆～C₂₀Aryl, or one or more heteroatoms selected from N, O and S, the number of heteroatoms being 1-3^1-5Substituted radicals containing C₂～C₂₀The heteroaryl group of (a); when the substituent is plural, it may be the same or different;

R^1-1、R^1-2and R^1-3Independently is C₁～C₁₈Alkyl radical, C₁～C₁₈Alkoxy, phenyl, or substituted by one or more R^1-1-1Substituted phenyl; when the substituent is plural, it may be the same or different;

R^1-4、R^1-5and R^1-1-1Independently of one another, halogen, C₁～C₁₈Alkyl, C substituted by one or more halogens₁～C₁₈Alkyl radical, C₁～C₁₈Alkoxy radical, C₁～C₁₈Alkyl O (C ═ O) -, C₁～C₁₈Alkyl (C ═ O) O-, C₁～C₁₈Alkyl (C ═ O) -, C₁～C₁₈Alkyl (C ═ O) NH —, [ C ═ O)₁～C₁₈Alkyl (C ═ O)]₂N-、R^1-4-1R^1-4-2R^1-4-3Si-、C₆～C₁₀An aryl group; when the substituent is plural, it may be the same or different;

R^1-4-1、R^1-4-2and R^1-4-3Independently is C₁～C₈Alkyl radical, C₁～C₈Alkoxy, phenyl, or substituted by one or more R^1-1-1Substituted phenyl; when the substituent is plural, it may be the same or different.

2. An oxaaromatic ring photocatalyst-based high activity radical polymerization system as claimed in claim 1, wherein: r₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅' independently is hydrogen, halogen, C₁～C₁₈Alkyl, C substituted by one or more halogens₁～C₁₈Alkyl, by one or more R^1-4Substituted C₆～C₂₀Aryl, one or more heteroatoms selected from N, O and S, the number of the heteroatoms being 1-3, and one or more R^1-5Substituted radicals containing C₂～C₁₂The heteroaryl group of (a); when the substituent is plural, it may be the same or different;

and/or, R^1-4And R^1-5Is halogen, C₁～C₁₈Alkyl, C substituted by one or more halogens₁～C₈Alkyl radical, C₁～C₁₈Alkoxy, C substituted by one or more halogens₁～C₈Alkoxy, by one or more R^1-1-1Substituted C₆～C₁₀An aryl group; when the substituent is plural, it may be the same or different;

and/or, R^1-1-1Independently is C₁～C₈Alkyl, C substituted by one or more halogens₁～C₈Alkyl radical, C₁～C₈Alkoxy radical, C₆～C₁₀An aryl group;

and/or, R₂And R₂' independently is hydrogen, halogen, C₁～C₁₈An alkyl group.

3. An oxaaromatic ring photocatalyst-based high activity radical polymerization system as claimed in claim 2, wherein:

when R is₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅' independently is C₁～C₁₈When alkyl, said C₁～C₁₈The alkyl group is selected from methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, cyclopentyl, cyclohexyl, octyl, dodecyl, tetradecyl, octadecyl;

when R is₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅' independently is C substituted by one or more halogen₁～C₁₈When the alkyl is selected from trifluoromethyl, perfluorobutyl and perfluorooctyl;

and/or when R₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅Independently is substituted by one or more R^1-4Substituted C₆～C₂₀When aryl, is selected from the group consisting of^1-4Substituted phenyl;

and/or, R^1-4Is C₁～C₁₈Alkyl, selected from methyl, ethyl, isopropyl, tert-butyl, cyclopentyl and cyclohexyl;

and/or, R^1-4Is C substituted by one or more halogens₁～C₈When alkyl, it is selected from trifluoromethyl;

and/or, R^1-4Is represented by one or more R^1-1-1Substituted C₆～C₁₀When aryl, is selected from the group consisting of^1-1-1Substituted phenyl and naphthyl;

when R is₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅' independently is ' one or more heteroatoms selected from N, O and S, the number of heteroatoms being 1-3 ', is substituted with one or more R^1-5Substituted C₂～C₁₂When the heteroaryl group of (A) is selected from furan, thiophene, pyrrole, thiazole, imidazole, pyridine, pyrazine, pyrimidine, pyridazine, or

And/or, R^1-5Is C₁～C₁₈Alkyl, selected from methyl, ethyl, isopropyl, tert-butyl, cyclopentyl and cyclohexyl;

and/or, R^1-5Is C substituted by one or more halogens₁～C₈When alkyl, it is selected from trifluoromethyl;

and/or, R^1-5Is represented by one or more R^1-1-1Substituted C₆～C₁₀When aryl, is selected from the group consisting of^1-1-1Substituted phenyl and naphthyl;

and/or, R^1-1-1Independently is C₁～C₈When the alkyl is selected from methyl, ethyl, isopropyl and tert-butyl; is C substituted by one or more halogens₁～C₈When the alkyl is trifluoromethyl; is C₆～C₁₀When aryl, it is phenyl.

4. An oxaaromatic ring photocatalyst-based high activity radical polymerization system as claimed in claim 3, wherein:

R₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅' is independently hydrogen, fluorine, chlorine, bromine, iodine, cyano, methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, cyclohexyl, trifluoromethyl, methoxy, ethoxy, methyl, ethyl, isopropyl, tert-butyl, cyclohexyl, trifluoromethyl, or mixtures thereof, and the like,

And/or, R₂And R₂Independently is hydrogen, fluorine, bromine.

5. An oxaaromatic ring photocatalyst based highly active radical polymerization system as claimed in claims 2-4 wherein said compound of formula I includes but is not limited to the following structures:

6. an oxaaromatic ring photocatalyst-based high activity radical polymerization system as claimed in claim 1, wherein: the initiator is a compound containing at least one C-X bond, N-X bond, S-X bond, O-X bond (X is a halogen element F/Cl/Br/I), thiocyanate group (-SCN), xanthate group (-S (C ═ S) OR), trithiocarbonate group (-S (C ═ S) SR), thiocarbamate group (-S (C ═ O) NRR'), including but not limited to the following: alkyl α -bromophenylacetate, alkyl 2-bromopropionate, alkyl 2-bromoisobutyrate, dialkyl bromomalonate, dialkyl 2-bromo-2-methylmalonate, 4-cyano-4- [ (alkylsulfonylthiocarbonyl) sulfonyl]-valeric acid and the like; the alkyl, R and R' are C₁-C₂₄Alkyl groups, including but not limited to: methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl, cyclohexyl.

7. An oxaaromatic ring photocatalyst-based high activity radical polymerization system as claimed in claim 6, wherein: the organic initiator exhibits a redox potential in the range of about-0.2V to about-2.0V in aqueous or organic solvents or mixtures thereof.

8. An oxaaromatic ring photocatalyst-based high activity radical polymerization system as claimed in claim 1, wherein: the monomers comprise unsaturated carbon-carbon or carbon-nitrogen bonds, including but not limited to the following: acrylates comprising optionally substituted alpha-olefins, dienes, internal olefins, cyclic olefins, acrylates, methacrylates, acrylonitrile, vinyl acetate, vinyl pivalate, vinyl ketones, vinyl aldehydes, dimethylvinylphosphonate, vinyl ethers, vinylamines, N-vinylpyrrolidone, acrylamide, methacrylamide, N, N-dimethylacrylamide, N- (2-hydroxypropyl) methacrylamide, N-isopropylacrylamide, oligoethylene glycols, methacrylates of oligoethylene glycols; the alpha-olefins include, but are not limited to, ethylene, propylene, butene, pentene, hexene, tetrafluoroethylene, vinyl chloride, or styrene; the diolefins include, but are not limited to, butadiene, isoprene or chloroprene; the internal olefins include, but are not limited to, 2-butene, 2-hexene or 3-hexene; the cyclic olefin includes, but is not limited to, norbornene, cyclopentene, cyclohexene, cyclooctene or cyclooctadiene.

9. An oxaaromatic ring photocatalyst-based high activity radical polymerization system as claimed in claim 1, wherein: the dioxaanthanthanthrene derivative is used as a photocatalyst or a photosensitizer, and the light source is a light source containing any waveband or a mixture of a plurality of wavebands of 300nm to 1000 nm; light sources include, but are not limited to, ultraviolet light, mercury lamps, incandescent lamps, fluorescent lamps, sunlight, LED light sources.

10. An oxaaromatic ring photocatalyst-based high activity radical polymerization system as claimed in claim 1, wherein: the concentration or amount of the photocatalyst or photosensitizer is from 0.001ppm to 1000 ppm.

Technical Field

The invention relates to the field of organic photocatalytic free radical polymerization, in particular to a living free radical polymerization system taking a xanthene compound (PXX) as an organic photocatalyst (or called photosensitizer). Under mild conditions, organic halide or sulfide is used as an initiating reagent, and controllable active free radical polymerization of various monomers such as methacrylate, acrylate monomers, styrene and the like under visible light can be realized.

Background

After an anionic polymerization method was reported by Szwarc et al in 1956, living polymerization became the most effective means in a polymer synthesis method, and thus the precise design of polymers and the regulation and control of specific structures and properties were realized. The Living controlled radical polymerization (Living controlled polymerization/controlled polymerization) has led to great research enthusiasm and interest of many researchers due to its relatively mild reaction conditions, wider applicable monomers, simple operation, low industrial cost, and other features and advantages. "living" controlled radical polymerization, including Atom Transfer Radical Polymerization (ATRP), organometallic radical polymerization (OMRP), nitroxide-mediated polymerization (NMP), and reversible addition-fragmentation chain transfer polymerization (RAFT), all provide the possibility for the precise construction of polymers with well-defined structures.

The introduction of external stimulation can realize the regulation and control of polymerization behaviors, such as photocatalytic polymerization, electrocatalytic polymerization, mechanical force control polymerization, redox agent control polymerization and the like. Light is widely used as an energy source in polymerization, and compared with conventional thermal polymerization, photopolymerization can be performed at normal temperature, is simple to operate, has a smooth reaction, and can be rapidly started and stopped by turning on/off. In addition, the photopolymerization reaction has low activation energy, and is suitable for polymerization of a temperature-sensitive monomer.

In conventional free radical polymerization, the equilibrium between dormant species and actively propagating radicals is mediated mostly by transition metal catalysts [ i.e., cu (i), ru (ii), fe (ii) ], to maintain low active radical species concentrations. It is important to minimize bimolecular termination and establish controlled/active chain growth. However, the use of transition metal catalysts will cause metal contamination and residue in the final polymerization product, which will accelerate the aging of the polymer, and this also severely limits its application in biomedical and electronic semiconductor industries. Therefore, since the initial discovery of photocatalytic free-radical polymerization, much research has been devoted to reducing the amount of catalyst used and the purification of the polymerization product in an effort to minimize the effects of metal residues on the product and application. Despite the great progress that has been made, the development of new catalytic systems for non-metal catalyzed free radical polymerization is undoubtedly an ideal solution to this problem.

Disclosure of Invention

The invention aims to highlight the high-efficiency catalytic capability of dioxaanthanthanthrene (PXX) compounds as organic photocatalysts in free radical polymerization, can realize the active free radical polymerization of monomers such as methacrylates, acrylates, styrenes, vinyl ethers and vinyl amines under the control of visible light, and has the advantages of high catalytic efficiency, wide applicable monomers, easiness in operation, repeatability and the like.

The invention adopts the following specific technical scheme:

a high activity free radical polymerization system based on oxygen heterocyclic photocatalyst comprises a monomer, a photocatalyst and an initiator; the photocatalyst is a dioxaanthanthanthrene compound, and the initiator is an organic halide or sulfide;

the structure of the photocatalyst is shown as formula I:

in the formula I, the compound is shown in the specification,

r1, R2, R3, R4, R5, R1 ', R2 ', R3 ', R4 ', and R5 ' are independently selected from hydrogen, halogen, cyano, C1 to C24 alkyl, C1 to C24 alkyl substituted with one or more halogens, C1 to C24 alkoxy, C1 to C24 alkyl O (C ═ O) -, C1 to C24 alkyl (C ═ O) O-, C1 to C24 alkyl (C ═ O) -, C1 to C24 alkyl (C ═ O) NH-, [ C1 to C24 alkyl (C ═ O) ]2N-, R1-1R1-2R1-3Si-, C1 to C1 aryl substituted with one or more R1-4, or "one or more heteroatoms selected from the group consisting of R1 and S" are selected from one or more of R1-1 and S ", and one or more of the group consisting of R1-1 and S1 and 365 and 1 is substituted with one or more C365-365 atoms; when the substituent is plural, it may be the same or different;

r1-1, R1-2, and R1-3 are independently C1-C18 alkyl, C1-C18 alkoxy, phenyl, or phenyl substituted with one or more R1-1-1; when the substituent is plural, it may be the same or different;

r1-4, R1-5 and R1-1-1 are independently halogen, C1-C18 alkyl, C1-C18 alkyl substituted with one or more halogens, C1-C18 alkoxy, C1-C18 alkyl O (C ═ O) -, C1-C18 alkyl (C ═ O) O-, C1-C18 alkyl (C ═ O) -, C1-C18 alkyl (C ═ O) NH-, [ C1-C18 alkyl (C ═ O) ]2N-, R1-4-1R1-4-2R1-4-3Si-, C6-C10 aryl; when the substituent is plural, it may be the same or different; r1-4-1, R1-4-2, and R1-4-3 are independently C1-C8 alkyl, C1-C8 alkoxy, phenyl, or phenyl substituted with one or more R1-1-1; when the substituent is plural, it may be the same or different.

The development of systems for non-metal catalyzed free radical polymerization is critical to the development of efficient organic catalysts. In view of this, based on the basic principle of "living" controllable free radical polymerization, we developed a dioxaanthanthrene (PXX) -based oxa-aromatic ring organic photocatalyst or photosensitizer, which can realize "living" controllable free radical polymerization of a series of alkenyl monomers under the irradiation of visible light. The oxa-aromatic ring photocatalyst is easy to prepare, low in air sensitivity, high in chemical stability, good in environmental tolerance and long in storage life, greatly reduces the cost of polymerization reaction and the later-stage treatment process compared with metal photocatalysis, and even can directly avoid the later-stage purification step of a polymerization product. Not only expands the range of the photocatalyst, but also has very wide application prospect in the field of controllable free radical polymerization, even in the field of photocatalytic small molecule synthesis.

At a certain temperature (which can be at room temperature), organic halide or sulfide is used as an initiator, PXX compounds are used as an organic photocatalyst or photosensitizer, and a series of vinyl monomers such as Methyl Methacrylate (MMA), benzyl methacrylate (BnMA), Butyl Methacrylate (BMA), Butyl Acrylate (BA), 2,2, 2-trifluoroethyl methacrylate (TFEMA), styrene (St) and the like are polymerized respectively to obtain a polymer with controllable molecular weight and narrow molecular weight distribution. Under the irradiation of a light source with the wavelength of 300-1000nm and under the loading of a photocatalyst in a wide temperature range (100 ℃ below zero to 100 ℃ above zero) in various solvents (polar, nonpolar or protic solvents) and different initiators (halogen or sulfur containing initiators), controllable free radical polymerization can be realized, the molecular weight of the polymer shows excellent linear growth along with the increase of the conversion rate, and the polymer with controllable molecular weight can be obtained. In addition, the obtained polymer has higher fidelity of terminal groups, and can be used as a macroinitiator to carry out chain extension reaction or be copolymerized with other olefin monomers to prepare a block polymer.

Preferably, R₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅' independently is hydrogen, halogen, C₁～C₁₈Alkyl, C substituted by one or more halogens₁～C₁₈Alkyl, by one or more R^1-4Substituted C₆～C₂₀Aryl, one or more heteroatoms selected from N, O and S, the number of the heteroatoms being 1-3, and one or more R^1-5Substituted radicals containing C₂～C₁₂The heteroaryl group of (a); when the substituent is plural, it may be the same or different;

and/or, R^1-4And R^1-5Is halogen, C₁～C₁₈Alkyl, C substituted by one or more halogens₁～C₈Alkyl radical, C₁～C₁₈Alkoxy, C substituted by one or more halogens₁～C₈Alkoxy, by one or more R^1-1-1Substituted C₆～C₁₀An aryl group; when the substituent is plural, it may be the same or different;

and/or, R^1-1-1Independently is C₁～C₈Alkyl, C substituted by one or more halogens₁～C₈Alkyl radical, C₁～C₈Alkoxy radical, C₆～C₁₀An aryl group;

and/or, R₂And R₂' independently is hydrogen, halogen, C₁～C₁₈An alkyl group.

Preferably, when R is₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅' independently is C₁～C₁₈When alkyl, said C₁～C₁₈The alkyl group is selected from methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, cyclopentyl, cyclohexyl, octyl, dodecyl, tetradecyl, octadecyl;

when R is₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅' independently is C substituted by one or more halogen₁～C₁₈When the alkyl is selected from trifluoromethyl, perfluorobutyl and perfluorooctyl;

and/or when R₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅Independently is substituted by one or more R^1-4Substituted C₆～C₂₀When aryl, is selected from the group consisting of^1-4Substituted phenyl;

and/or, R^1-4Is C₁～C₁₈Alkyl, selected from methyl, ethyl, isopropyl, tert-butyl, cyclopentyl and cyclohexyl;

and/or, R^1-4Is C substituted by one or more halogens₁～C₈When alkyl, it is selected from trifluoromethyl;

and/or, R^1-4Is represented by one or more R^1-1-1Substituted C₆～C₁₀When aryl, is selected from the group consisting of^1-1-1Substituted phenyl and naphthyl;

when R is₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅' independently is ' one or more heteroatoms selected from N, O and S, the number of heteroatoms being 1-3 ', is substituted with one or more R^1-5Substituted C₂～C₁₂When the heteroaryl group is selected from furan, thiophene and pyridinePyrrole, thiazole, imidazole, pyridine, pyrazine, pyrimidine, pyridazine, or

And/or, R^1-5Is C₁～C₁₈Alkyl, selected from methyl, ethyl, isopropyl, tert-butyl, cyclopentyl and cyclohexyl;

and/or, R^1-5Is C substituted by one or more halogens₁～C₈When alkyl, it is selected from trifluoromethyl;

and/or, R^1-5Is represented by one or more R^1-1-1Substituted C₆～C₁₀When aryl, is selected from the group consisting of^1-1-1Substituted phenyl and naphthyl;

and/or, R^1-1-1Independently is C₁～C₈When the alkyl is selected from methyl, ethyl, isopropyl and tert-butyl; is C substituted by one or more halogens₁～C₈When the alkyl is trifluoromethyl; is C₆～C₁₀When aryl, it is phenyl.

Preferably, R₁、R₃、R₄、R₅、R₁’、R₃’、R₄' and R₅' is independently hydrogen, fluorine, chlorine, bromine, iodine, cyano, methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, cyclohexyl, trifluoromethyl, methoxy, ethoxy, methyl, ethyl, isopropyl, tert-butyl, cyclohexyl, trifluoromethyl, or mixtures thereof, and the like,

And/or, R₂And R₂Independently is hydrogen, fluorine, bromine.

Preferably, the compound of formula I includes, but is not limited to, the following structures:

preferably, the initiator is a compound containing at least one C — X bond, N — X bond, S — X bond, O — X bond (X is a halogen element F/Cl/Br/I), thiocyanate group (-SCN), xanthate group (-S (C ═ S) OR), trithiocarbonate group (-S (C ═ S) SR), thiocarbamate group (-S (C ═ O) NRR'), including but not limited to the following: alkyl α -bromophenylacetate, alkyl 2-bromopropionate, alkyl 2-bromoisobutyrate, dialkyl bromomalonate, dialkyl 2-bromo-2-methylmalonate, 4-cyano-4-[ (alkylsulfonylthiocarbonyl) sulfonyl]-valeric acid and the like; the alkyl, R and R' are C₁-C₂₄Alkyl groups, including but not limited to: methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl, cyclohexyl.

Preferably, the organic initiator exhibits a redox potential in the range of about-0.2V to about-2.0V in aqueous or organic solvents or mixtures thereof.

Preferably, the monomer contains an unsaturated carbon-carbon or carbon-nitrogen bond, including but not limited to the following: acrylates comprising optionally substituted alpha-olefins, dienes, internal olefins, cyclic olefins, acrylates, methacrylates, acrylonitrile, vinyl acetate, vinyl pivalate, vinyl ketones, vinyl aldehydes, dimethylvinylphosphonate, vinyl ethers, vinylamines, N-vinylpyrrolidone, acrylamide, methacrylamide, N, N-dimethylacrylamide, N- (2-hydroxypropyl) methacrylamide, N-isopropylacrylamide, oligoethylene glycols, methacrylates of oligoethylene glycols; the alpha-olefins include, but are not limited to, ethylene, propylene, butene, pentene, hexene, tetrafluoroethylene, vinyl chloride, or styrene; the diolefins include, but are not limited to, butadiene, isoprene or chloroprene; the internal olefins include, but are not limited to, 2-butene, 2-hexene or 3-hexene; the cyclic olefin includes, but is not limited to, norbornene, cyclopentene, cyclohexene, cyclooctene or cyclooctadiene.

Preferably, the dioxaanthanthanthrene derivative is used as a photocatalyst or photosensitizer, and the light source is a light source containing any wavelength band or a mixture of multiple wavelength bands of 300nm to 1000 nm; light sources include, but are not limited to, ultraviolet light, mercury lamps, incandescent lamps, fluorescent lamps, sunlight, LED light sources.

Preferably, the concentration or amount of photocatalyst or photosensitizer is from 0.001ppm to 1000 ppm.

Further, the molar ratio of the monomer to the initiating reagent is 1:1-10000:1, the amount of the catalyst can be 0.001ppm to 1000ppm, the reaction temperature is-100 ℃ to-100 ℃, the reaction is generally carried out at room temperature, and the light source comprises light with the wavelength of 300nm to 1000 nm; the polymerization system has mild condition, and the dioxaanthanthrene compound (PXX) is firstly used as a photocatalyst or a photosensitizer to be applied to free radical polymerization.

The substituted dioxaanthanthanthrene (PXX) oxaaromatic ring photocatalyst can be prepared by the following method.

The first method is to prepare dioxaanthanthrene (PXX) compounds through oxidative cyclization of substituted binaphthol.

Typical synthetic procedures: adding monovalent cuprous halide (cuprous iodide, cuprous chloride and the like) and a ligand into a solution of the substituted binaphthol compound, and carrying out ring closure oxidation under an acidic condition at a high temperature by using DMSO as a solvent and oxygen as an oxidant, pivalic acid and the like or under an alkaline condition at a high temperature by using polysubstituted benzene as a solvent and oxygen as an oxidant, and potassium carbonate and the like to generate the substituted PXX compound.

Method II for preparing substituted PXX compounds by derivatization of unsubstituted dioxaanthanthrene

Typical synthetic procedures: adding more than 2 equivalents of n-butyllithium into an unsubstituted PXX solution, removing hydrogen on carbon near an oxygen atom, halogenating (iodinating or brominating) at low temperature or directly halogenating without adding n-butyllithium to generate a dihalogenated product, and introducing a substituent by Suzuki coupling or Kumada coupling with corresponding borate, Grignard reagent and the like to synthesize the PXX compound substituted at the corresponding position.

The polymerization is carried out in a manner similar to other living radical polymerization, requiring the prior exclusion of the reactants and oxygen from the reaction tube. The monomer, the initiator, the photocatalyst and the solvent are sequentially put into a reaction vessel with stirring, the oxygen can be removed by circularly degassing through a freezing and thawing pump according to needs, and finally the reaction system is filled with inert atmosphere for protection. At a certain temperature, a proper artificial light source is selected or sunlight is directly adopted to initiate polymerization. The reaction was monitored and a small amount of the reaction mixture was added to deuterated chloroform containing BHT (250ppm) to terminate the polymerization and the conversion was monitored by nuclear magnetism. After reaching the predetermined conversion, the polymer itself may be settled or the reaction solution may be poured into a poor solvent (usually methanol) for settling separation, and then washed and dried to obtain the polymer product. For polymer analysis, the dried polymer was taken to prepare a tetrahydrofuran solution (concentration 1-1.5mg/mL) and passed through a syringe filter, and the molecular weight and polydispersity of the polymer were measured by GPC as the filtered solution. The maximum emission of the purple LED light source used in the implementation example is 400nm, the wavelength range is 375nm-425 nm, the maximum emission of the blue LED light source is 460nm, and the wavelength range is 435-485 nm.

The above monomers are monomers containing a carbon-carbon double bond or a carbon-nitrogen double bond, including but not limited to the following: comprising an optionally substituted alpha-olefin (including but not limited to ethylene, propylene, butene, pentene, hexene, tetrafluoroethylene, vinyl chloride, or styrene), a diene (including but not limited to butadiene, isoprene, or chloroprene), an internal olefin (including but not limited to 2-butene, 2-hexene, or 3-hexene), a cyclic olefin (including but not limited to norbornene, cyclopentene, cyclohexene, cyclooctene, or cyclooctadiene), an acrylate, a methacrylate, acrylonitrile, vinyl acetate, vinyl pivalate, a vinyl ketone, a vinyl aldehyde, dimethylvinylphosphonate, a vinyl ether, a vinylamine, N-vinylpyrrolidone, acrylamide, methacrylamide, N, N-dimethylacrylamide, N- (2-hydroxypropyl) methacrylamide, n-isopropylacrylamide, oligoethylene glycol acrylates, oligoethylene glycol methacrylates, and the like. Examples of monomers used include Methyl Methacrylate (MMA), benzyl methacrylate (BnMA), Butyl Methacrylate (BMA), Butyl Acrylate (BA), trifluoroethyl 2,2, 2-methacrylate (TFEMA), styrene (St), and the like.

Chain extension experiments: before polymerization, a macromolecule initiator prepared in advance is fully dried, stored in a dark place, accurately weighed, and added with a monomer, a PXX photocatalyst and a solvent according to an optimized proportion condition, mixed, placed in a reaction container, sealed, and subjected to degassing by circulation of a freezing and thawing pump, so that polymerization is carried out in an inert atmosphere.

The macroinitiator is prepared by homopolymerization, and examples include polymethyl methacrylate (PMMA-Br), poly benzyl methacrylate (PBnMA-Br) and polybutyl acrylate (PBA-Br).

The substituted PXX derivative used in the invention is used as a photocatalyst, has strong reducibility after excitation, and the organic catalyst PC is changed into excited PC under the irradiation of a light source^*PC in an excited state^*The method is used for reducing bromide or sulfide to generate free radicals and bromine or sulfur-containing negative ions, the free radicals are used for initiating polymerization of monomers to form chain propagation, then the anions and active chain free radicals (active propagation chains) react, electrons are transferred out, the organic photocatalyst returns to a ground state PC, and meanwhile, the active free radical chains form macromolecule dormant species after deactivation. The circulation is carried out, and the reversible balance between the dormant species and the active chain-lengthening species is kept through activation and deactivation, so that a polymerization reaction system has certain controllability, and the homopolymer or the block copolymer with controllable molecular weight and narrow molecular weight distribution is obtained. The preparation method provided by the invention is simple and easy to implement, easy to operate and repeat and high in practicability.

Description of the drawings:

FIG. 1 is a diagram of a 6W violet light reactor and a 6W blue light reactor and a reaction apparatus for photoreactive polymerization under irradiation of sunlight;

FIG. 2 is a nuclear magnetic hydrogen spectrum of the polymer PMMA in the example;

FIG. 3 is a GPC chart of a chain extension and copolymerization experiment of a macroinitiator at 500ppm catalyst loading in the examples;

FIG. 4 is a first order kinetic plot of homopolymer preparation at low catalyst usage in the examples;

FIG. 5 is a GPC chart of a chain extension and copolymerization experiment at 10ppm catalyst loading in the examples;

FIG. 6 is a nuclear magnetic hydrogen spectrum of a benzyl methacrylate polymer isolated in an example;

FIG. 7 is a nuclear magnetic hydrogen spectrum of a trifluoroethyl 2,2, 2-methacrylate polymer isolated in the example.

Detailed Description

The present invention is specifically described below by way of some examples, but the present invention is not limited to only these examples.

Example one

Photopolymerization experiment of MMA catalyzed by PXX 1

The concentration fraction of monomeric MMA in Dichloromethane (DCM) solvent was 9.4M. The above raw materials were charged into 10mL Schlenk tubes, respectively, in a molar ratio of [ MMA ]: [ EBP ]: [ PXX 1 ]: 100:1:0.05, sealed, and the reaction mixture was degassed by a freeze thaw pump cycle so that the polymerization was carried out in an inert atmosphere. The reaction mixture was stirred well with a magnetic stirrer at room temperature and was irradiated by a purple LED (6W) (control distance from the center of the reaction tube to the light source of 2cm) and irradiated in parallel by a blue LED (6W) (control distance from the center of the reaction tube to the light source of 2 cm). (reaction apparatus shown in FIG. 1) at regular intervals, a small amount of the reaction mixture was added to deuterated chloroform containing BHT (250ppm) to terminate the polymerization, the conversion was monitored by nuclear magnetism, the remaining reaction solution was settled in rapidly stirred methanol, and the resulting precipitate was dried under reduced pressure to constant weight to obtain a white powder. The dried polymer was taken to prepare a tetrahydrofuran solution (concentration 1-1.5mg/mL) and passed through a syringe filter, and the molecular weight and polydispersity of the polymer were measured by GPC as the filtered solution.

Under the proportioning condition, the molecular weight of the polymer increases linearly with the increase of the conversion rate.

When the ultraviolet LED irradiates for 8 hours, the monomer conversion rate reaches 73.3 percent, and the M of a polymerization product_n12.8kDa, PDI 1.25; after the blue LED irradiates for 8 hours, the monomer conversion rate reaches 78.2 percent, and the M of the polymerization product_n＝14.0kDa,PDI＝1.24.

Under the proportioning condition, the light switch experiment shows that the polymerization is dependent on light, can be converted only in the light and is not converted in the dark.

Comparative example 1

The concentration fraction of monomer MMA in the solvent (N, N-dimethylacetamide, toluene, tetrahydrofuran) was 9.4M. The above raw materials were added to 10mL Schlenk tubes, respectively, in a molar ratio of [ MMA ]: [ EBP ]: [ PXX 1 ]: 100:1:0.5, sealed, and the reaction mixture was degassed by a freeze thaw pump cycle so that the polymerization was carried out under violet light in an inert atmosphere. Other operations refer to embodiment one.

When the system solvent was changed to N, N-Dimethylacetamide (DMA), the reaction was carried out for 8h with 88.5% conversion to obtain M_nPolymer of 20.1kDa (PDI 1.34) in toluene for 8h with 87.5% conversion to M_n17.4kDa polymer (PDI 1.32); reaction for 8h with 91.2% conversion in tetrahydrofuran solvent gave M_nThe Polymer (PDI) of 21.4kDa is 1.37, which shows that the control of dichloromethane as a solvent is obviously better than that of other solvents such as N, N-dimethylacetamide, and the selection of the solvent is very important for the control capability of the polymerization reaction.

Comparative example II

The concentration fraction of monomeric MMA in Dichloromethane (DCM) was 9.4M. The above raw materials were charged into 10mL Schlenk tubes, respectively, in molar ratios [ MMA ]: [ initiator ]: [ PXX 1 ]: 100:1:0.5[ initiators were ethyl 2-bromopropionate, ethyl 2-bromoisobutyrate, diethyl bromomalonate, and diethyl 2-bromo-2-methylmalonate ], respectively, sealed, and the reaction mixture was degassed by a freeze thaw pump cycle so that polymerization was carried out under violet light in an inert atmosphere. Other operations refer to embodiment one.

When the initiator was changed to ethyl 2-bromopropionate, the reaction was 8h with 72.7% conversion to give M_n13.3 kDa polymer (PDI 1.27); reaction for 8h with 78.2% conversion of the initiator ethyl 2-bromoisobutyrate gave M_n14.7kDa polymer (PDI 1.24); when the initiator is diethyl bromomalonate, the reaction is carried out for 8h, and the conversion is 80.8 percent to obtain M_n13.7kDa polymer (PDI 1.22); reaction for 8h with 81.2% conversion to give M when the initiator is diethyl 2-bromo-2-methylmalonate_nA 12.1kDa polymer (PDI 1.19); the initiation of the 2-bromo-2-methyl diethyl malonate is obviously better than that of other initiators, and the selection of the initiators is very important for controlling the polymerization reaction.

Example two

Photopolymerization experiment of MMA initiated by PXX 42/2-bromine-2-diethyl methylmalonate (DBMM)

The concentration fraction of monomeric MMA in Dichloromethane (DCM) solvent was 9.4M. The above raw materials were charged into a 10mL Schlenk tube in molar ratios [ MMA ]: [ DBMM ]: [ PXX 42] ═ 100:2:0.05, 100:1:0.05 and 200:1:0.05, respectively, sealed, and the reaction mixture was degassed by a freeze thaw pump cycle so that polymerization was carried out under violet light in an inert atmosphere. Other operations refer to embodiment one.

In [ MMA ]]:[DBMM]:[PC]The reaction is carried out for 8 hours under the condition of the mixture ratio of 100:2:0.05, the monomer conversion rate reaches 62.5 percent, and the M of a polymerization product_n＝6.40kDa,PDI＝1.13。

In [ MMA ]]:[DBMM]:[PC]100: the mixture ratio of 1:0.05 is reacted for 8 hours, the monomer conversion rate reaches 81.9 percent, and M of a polymerization product_n＝12.7kDa,PDI＝1.12。

In [ MMA ]]:[DBMM]:[PC]The reaction is carried out for 8 hours under the condition of the mixture ratio of 200:1:0.05, the monomer conversion rate reaches 62.9 percent, and the M of a polymerization product_n＝17.8kDa,PDI＝1.27。

It is shown that as the ratio of monomer to initiator increases, the control of the overall polymerization is somewhat reduced, and that as the ratio of monomer to initiator decreases, the polydispersity of the polymer decreases and more excellent control is obtained.

EXAMPLE III

Preparation of PMMA-Br macroinitiator

MMA (5.00mL,47mmol,1000eq.), dbm (180 μ L,940 μmol,20eq.) and photocatalyst PXX 42(23.5 μmol,0.5eq.) were dissolved in 7.50mL DCM, the above raw materials were added to a 10mL Schlenk tube, sealed, and the reaction mixture was degassed by a freeze thaw pump cycle so that polymerization was carried out under violet light in an inert atmosphere. Other operations refer to embodiment one. After 6h of reaction, the reaction was removed, poured into 400mL of methanol and stirred for 5 h. The resulting precipitate was then isolated by vacuum filtration and washed with excess methanol. The polymer was then redissolved in a minimum amount of DCM, poured again into 200mL of methanol and stirred for 3 h. The product was collected again by vacuum filtration and dried under reduced pressure to give a white powder (polymer nuclear magnetism as in FIG. 2) (M)_n4.10kDa, PDI 1.19, schemeGPC trace in 3).

Example four

Chain extension experiment of PMMA-b-PMMA

MMA (310 μ L,2.90mmol,240eq.), PMMA macroinitiator (see above) (50 mg,12 μmol,1eq.), and photocatalyst PXX 42(0.05eq.) were dissolved in 1.00mL DCM, the above raw materials were added to a 10mL Schlenk tube, sealed, and the reaction mixture was degassed by a freeze thaw pump cycle such that the polymerization was carried out under violet light in an inert atmosphere. Other operations refer to embodiment one. After 10h of reaction, the reaction was removed, poured into 100mL of methanol and stirred for 3 h. The resulting precipitate was then isolated by vacuum filtration and washed with excess methanol. The polymer was then redissolved in a minimum amount of DCM, poured again into 50mL of methanol and stirred for 2 h. The resulting polymer was isolated and analyzed according to the general polymerization procedure described above (M)_n32.5 kDa, PDI 1.45) (GPC traces in FIG. 3)

EXAMPLE five

PMMA-b-PBnMA Block experiment

PMMA macroinitiator (see above) (41mg,10 μmol,1eq.), BnMA (610 μ L, 3.6mmol,360eq.) and PXX 42(0.05eq.) were dissolved in 1.50mL DCM and the above raw materials were added to a 10mL Schlenk tube, sealed and the reaction mixture was degassed by a freeze thaw pump cycle so that the polymerization was carried out under violet light in an inert atmosphere. Other operations refer to embodiment one. After 10h of reaction, the reaction was removed, poured into 150mL of methanol and stirred for 5 h. The resulting precipitate was then isolated by vacuum filtration and washed with excess methanol. The resulting polymer was isolated and analyzed according to the general polymerization procedure described above (M)_n98.2kDa, PDI 1.58) (GPC traces in FIG. 3)

EXAMPLE six

PMMA-b-PBA Block experiment

PMMA macroinitiator (see above) (41mg,10 μmol,1eq.), BA (518 μ L, 3.6mmol,400eq.), and PXX 42(0.05eq.) were dissolved in 1.50mL DCM and the above raw materials were added to a 10mL Schlenk tube, sealed, and the reaction mixture was degassed by a freeze thaw pump cycle so that the polymerization was carried out under violet light in an inert atmosphere. Other operations refer to embodiment one. After 7h of reaction, the reactants were removed,poured into 150mL of methanol and stirred for 5 h. The resulting precipitate was then isolated by vacuum filtration and washed with excess methanol. The resulting polymer was isolated and analyzed according to the general polymerization procedure described above (M)_n215kDa and PDI 1.66) (GPC trace in fig. 3)

EXAMPLE seven

Polymerization investigation at Low catalyst loadings

Catalyst PXX 42 was first prepared as a dilute solution (4.7 μmol,1eq. dissolved in 5mL of DCM) at a concentration, i.e. a pre-made solution, and added in molar volume, with secondary dilution if necessary. MMA (1.00mL,9.4mmol,1000eq.), DBMM (18. mu.L, 94. mu. mol,10eq.) and photocatalyst PXX 42 (0.47. mu. mol,0.05eq., 50ppm relative to the monomer) were dissolved in 1.20mL of DCM, the above raw materials were added in succession to a 10mL Schlenk tube, the entire operation was carried out in a glove box, and before the start of the polymerization, the operation was carried out in the dark, and immediately after the glove box was taken out, the polymerization was started under blue light. Other operations refer to embodiment one. After 12h of reaction, the reaction was removed, poured into 150mL of methanol and stirred for 5 h. The resulting precipitate was then isolated by vacuum filtration and washed with excess methanol. The polymer was then redissolved in a minimum amount of DCM, poured again into 50mL of methanol and stirred for 2 h. The product was collected again by vacuum filtration and dried under reduced pressure to give a white powder (M)_n＝13.7kDa,PDI＝1.18)

Comparative example III

MMA (1.00mL,9.4mmol,1000eq.), DBMM (18. mu.L, 94. mu. mol,10eq.) and photocatalyst PXX 42 (0.094. mu. mol,0.01eq., 10ppm relative to the monomer) were dissolved in 1.20mL DCM, the above raw materials were charged into a 10mL Schlenk tube, the entire operation was carried out in a glove box, and before the start of the polymerization, the operation was carried out in the dark, and immediately after the glove box was taken out, the polymerization was started under blue light. Other operations refer to embodiment one.

When the catalyst level was reduced to 10ppm, the reaction was carried out for 14h with a conversion of 90.4% to give M_nA polymer of 14.5 kDa (PDI 1.17) indicates that there is still good control of 10ppm catalyst level, which can be reduced from 500ppm to 50ppm, and further to 10ppm still maintains good control of end group fidelity and chain growth.

Comparative example four

MMA (1.00mL,9.4mmol,1000eq.), DBMM (18. mu.L, 94. mu. mol,10eq.) and photocatalyst PXX 42 (0.047. mu. mol,0.005eq., 5ppm relative to the monomer) were dissolved in 1.20mL DCM, the above starting materials were charged to a 10mL Schlenk tube, the entire operation was carried out in a glove box, and before the start of the polymerization, the operation was carried out in the dark, and immediately after the glove box was taken out, the polymerization was started under blue light. Other operations refer to embodiment one.

When the catalyst level was reduced to 5ppm, the reaction was carried out for 14h with 83.2% conversion to give M_nA polymer of 14.3 kDa (PDI 1.25) indicates that 5ppm catalyst level is still effective, with a slight decrease in initiation efficiency, but still maintaining good polydispersity control.

Comparative example five

MMA (1.00mL,9.4mmol,1000eq.), DBMM (18. mu.L, 94. mu. mol,10eq.) and photocatalyst PXX 42 (0.0094. mu. mol,0.001eq., 1ppm relative to the monomer) were dissolved in 1.20mL DCM, the above-mentioned raw materials were charged into a 10mL Schlenk tube and the whole operation was carried out in a glove box, and before the start of the polymerization, operation was kept out of the light, immediately after the glove box was taken out, the polymerization was started under blue light. Other operations refer to embodiment one.

The catalyst dosage was reduced to 1ppm, the reaction was 14h with 85.5% conversion to give M_n17.8kDa polymer (PDI 1.30), indicating that 1ppm catalyst level still maintains good control of chain ends and chain growth and that the polydispersity of the resulting polymer product is < 1.30.

Comparative example six

MMA (1.00mL,9.4mmol,1000eq.), DBMM (18. mu.L, 94. mu. mol,10eq.) and photocatalyst PXX 42 (0.0047. mu. mol,0.0005eq., 0.5ppm relative to the monomer) were dissolved in 1.20mL DCM, the above starting materials were charged to a 10mL Schlenk tube, the entire operation was carried out in a glove box, and before the polymerization started, the operation was kept out of the light, immediately after the glove box was taken out, the polymerization was started under blue light. Other operations refer to embodiment one.

When the catalyst level was reduced to 0.5ppm, the reaction was carried out for 14h with 77.4% conversion to give M_n19.2 kDa polymer (PDI 1.34), may be usedThe deviation between the experimental molecular weight and the theoretical molecular weight is obviously seen, the polydispersity is larger, but still less than or equal to 1.35, and the catalyst shows extremely high catalytic efficiency. .

Comparative example seven

MMA (1.00mL,9.4mmol,1000eq.), DBMM (18. mu.L, 94. mu. mol,10eq.) and photocatalyst PXX 42 (0.00047. mu. mol,0.00005eq., 0.05ppm relative to the monomer) were dissolved in 1.50mL DCM, the above starting materials were charged to a 10mL Schlenk tube, the entire operation was carried out in a glove box, and before the start of the polymerization, the operation was carried out protected from light, and immediately after the glove box was taken out, the polymerization was started under blue light. Other operations refer to embodiment one.

When the catalyst level was reduced to 0.05ppm, the reaction was 15h with a conversion of 62.5% to give M_n30.8 kDa polymer (PDI 1.51), which is impressive, robust catalytic capability, and is also a real example of a non-metallic catalyst at very low catalyst loadings.

Example eight

Kinetic investigation at Low catalyst loadings (10ppm)

MMA (2.00mL,18.8mmol,2000eq.), DBMM (18. mu.L, 94. mu. mol,10eq.) and photocatalyst PXX 42 (0.188. mu. mol,0.01eq.) were dissolved in 2.50mL DCM and the above raw materials were added sequentially to a 10mL Schlenk tube, the entire operation was conducted in a glove box and before the polymerization started, the operation was kept out of the light, and immediately after the glove box was taken out, the polymerization was started under blue light. Other operations refer to embodiment one. The polymerization was stopped by adding a small amount of the reaction mixture to deuterated chloroform containing BHT (250ppm) at intervals, monitoring the conversion by nuclear magnetism, settling the remaining reaction solution in rapidly stirred methanol, drying the resulting precipitate under reduced pressure to constant weight to give a white powder, redissolving the polymer in a minimum amount of DCM, pouring again into 200mL of methanol and stirring for 1 h. The resulting precipitate was dried under reduced pressure to constant weight to give a white powder. The dried polymer was taken to prepare a tetrahydrofuran solution (concentration 1-1.5mg/mL) and passed through a syringe filter, and the molecular weight and polydispersity of the polymer were measured by GPC as the filtered solution. (see fig. 4).

Example nine

Preparation of macroinitiator PMMA-Br under 10ppm catalyst dosage

MMA (5.00mL,47mmol,1000eq.), DBMM (180. mu.L, 940. mu. mol,20eq.) and photocatalyst PXX 42 (0.47. mu. mol,0.01eq., 10ppm relative to the monomer) were dissolved in 7.50mL DCM, and the above raw materials were charged into a 10mL Schlenk tube, the entire operation was conducted in a glove box, and before the polymerization started, the operation was kept out of the light, and immediately after the glove box was taken out, the polymerization was started under blue light. Other operations refer to embodiment one. After 8h of reaction, the reaction was removed, poured into 400mL of methanol and stirred for 5 h. The resulting precipitate was then isolated by vacuum filtration and washed with excess methanol. The polymer was then redissolved in a minimum amount of DCM, poured again into 200mL of methanol and stirred for 3 h. The product was collected again by vacuum filtration and dried under reduced pressure to give a white powder (M)_n8.40kDa, PDI 1.20, GPC traces in FIG. 5)

Example ten

Chain extension experiment of PMMA-b-PMMA

165mg of the above-mentioned PMMA macroinitiator (M)_n8.40kDa,1.0eq) was dissolved in 0.90 mL of DCM, 0.46mL of MMA (4.33X 10)^-3mol,220eq.),PXX 42(1.97×10^-8mol,0.001eq.) (which had been prepared as a dilute solution for accurate addition, the same applies below) were added in succession to 10mL Schlenk tubes, respectively, and reacted for 10h under blue light according to the general polymerization procedure described above, with the other operations being referred to example one. Then added dropwise to 100mL of methanol and stirred for 3h, the resulting precipitate was isolated by vacuum filtration and washed with excess methanol. The polymer was then redissolved in a minimum amount of DCM, poured again into 50mL of methanol and stirred for 2h, and dried in a vacuum oven until constant weight at 30 ℃ to yield 0.341g of polymer (57% conversion by gravimetric method) the resulting chain-extended PMMA-b-PMMA was isolated and analyzed according to the general polymerization method described above (M)_n22.8kDa, PDI 1.46, GPC traces in FIG. 5)

EXAMPLE eleven

PMMA-b-PBnMA Block experiment

142mg of the above PMMA macroinitiator (M)_n8.40kDa,1.0eq.) in 1.20mL DCM, 0.58mL bmma (3.4 × 10)^-3mol,202eq.),PXX 42(1.69×10^-8mol,0.001eq.) were added in succession to 10mL Schlenk tubes and reacted for 10h under blue light according to the general polymerization procedure described above, the other operations referring to example one. After 10h of reaction, added dropwise to 100mL of methanol and stirred for 5h, the resulting precipitate was isolated by vacuum filtration and washed with excess methanol. The polymer was then redissolved in a minimal amount of DCM, poured again into 50mL of methanol and stirred for 2h, and dried in a vacuum oven until constant weight at 30 ℃ to yield 0.350g of polymer (47% yield). M of the resulting PMMA-b-BnMA copolymer was found_n34.2kDa and PDI 1.60. (GPC traces in FIG. 5).

Example twelve

PMMA-b-PBA Block experiment

172mg of the above-mentioned PMMA macroinitiator (M)_n8.40kDa,1.0eq.) in 1.2mL DCM, 0.58mL BA (4.01 × 10)^-3mol,196eq.),PXX 42(2.04×10^-8mol,0.001eq.) were added in succession to 10mL Schlenk tubes and reacted for 7h under blue light according to the general polymerization procedure described above, the other operations referring to example one. After 7h of reaction, it was added dropwise to 100mL of methanol and stirred for 2h to give a yellow oil, and the solution was placed in a refrigerator (ca. -20 ℃ C.) for 1 h. The methanol was then decanted off and the residual solvent was removed under reduced pressure. This procedure was repeated once to obtain 0.358g of a yellow oil (yield 52%), M of the resulting PMMA-b-BA copolymer_n125kDa, PDI 1.65 (GPC curve in FIG. 5)

EXAMPLE thirteen

Polymerization investigation of 50ppm catalyst dosage under solar irradiation

Catalyst PXX 42 was first prepared as a dilute solution (4.7 μmol,1eq. dissolved in 5mL of DCM) at a concentration, i.e. a pre-made solution, and added in molar amount based on volume. MMA (1.00mL,9.4mmol,1000eq.), DBMM (18. mu.L, 94. mu. mol,10eq.) and photocatalyst PXX 42 (0.47. mu. mol,0.05eq., 50ppm relative to the monomer) were dissolved in 1.20mL DCM, and the above raw materials were added sequentially to 10mL Schlenk tubes, the entire operation was carried out in a glove box, and before the polymerization started, the operation was carried out in the dark, and immediately after taking out the glove box, the apparatus was set up and started under daylight. Co-reacting from 9 am to 4 pmAfter 7h, 49.2% conversion was determined by sampling nuclear magnetism, poured into 150mL methanol and stirred for 3h, and the resulting precipitate was isolated by vacuum filtration and washed with excess methanol. The polymer was then redissolved in a minimum amount of DCM, poured again into 50mL of methanol and stirred for 1 h. The product was collected again by vacuum filtration and dried under reduced pressure to give a white powder (M)_n＝9.40kDa，PDI＝1.22)。

Example fourteen

Homopolymerization of benzyl methacrylate at 50ppm catalyst level

Catalyst PXX 42 was first prepared as a dilute solution (4.7 μmol,1eq. dissolved in 5mL of DCM) at a concentration, i.e. a pre-made solution, and added in molar amount based on volume. BnMA (1.72mL, 9.4mmol,1000eq.), DBMM (18 μ L,94 μmol,10eq.) and photocatalyst PXX 42(0.47 μmol,0.05eq., 50ppm relative to monomer) were dissolved in 1.80mL DCM, the above raw materials were added sequentially to 10mL Schlenk tubes, the entire operation was conducted in a glove box, and before the polymerization started, the operation was conducted away from light, and immediately after the glove box was taken out, the polymerization was started under blue light. Other operations refer to embodiment one. After 10h of reaction, the reaction was removed, poured into 200mL of methanol and stirred for 5h, and the resulting precipitate was isolated by vacuum filtration and washed with excess methanol. The polymer was then redissolved in a minimum amount of DCM, poured again into 100mL of methanol and stirred for 3 h. The sample was taken under nuclear magnetic resonance to determine a conversion of 93.5%, and the product was collected again by vacuum filtration and dried under reduced pressure to give a white powder (M)_n＝11.5kDa，PDI＝1.29)。

Example fifteen

Homopolymerization study of butyl acrylate at 10ppm catalyst

Catalyst PXX 42 was first prepared as a dilute solution (4.7 μmol,1eq. dissolved in 5ml DCM) at a concentration, i.e. a pre-made solution, and added in molar amount, based on volume. BA (1.35mL,9.4mmol,1000eq.), DBMM (18. mu.L, 94. mu. mol,10eq.) and photocatalyst PXX 42 (0.094. mu. mol,0.01eq., 10ppm relative to the monomer) were dissolved in 1.50mL of DCM, the above raw materials were added sequentially to 10mL of Schlenk tubes, the entire operation was conducted in a glove box, and before the polymerization started, the operation was conducted away from light, after taking out the glove box,the polymerization was immediately allowed to proceed under blue light. Other operations refer to embodiment one. After 7h of reaction, the reaction was removed, poured into 150mL of methanol and stirred for 3h, and the resulting precipitate was isolated by vacuum filtration and washed with excess methanol. The polymer was then redissolved in a minimum amount of DCM, poured again into 100mL of methanol and stirred for 1 h. Sample NMR gave a 81.3% conversion, and the product was collected again by vacuum filtration and dried under reduced pressure to give a white powder (M)_n＝34.2kDa，PDI＝1.51)。

Example sixteen

Homopolymerization study of trifluoroethyl 2,2, 2-methacrylate at 10ppm catalyst level

Catalyst PXX 42 was first prepared as a dilute solution (4.7 μmol,1eq. dissolved in 5mL of DCM) at a concentration, i.e. a pre-made solution, and added in molar amount based on volume. TFEMA (1.33mL,9.4mmol, 1000eq.), DBMM (18 μ L,94 μmol,10eq.) and photocatalyst PXX 42(0.094 μmol,0.01eq., 10ppm relative to the monomer) were dissolved in 1.20mL DCM, the above raw materials were added sequentially to a 10mL Schlenk tube, the entire operation was conducted in a glove box, and before the start of the polymerization, the operation was conducted away from light, and immediately after the glove box was taken out, the polymerization was started under blue light. Other operations refer to embodiment one. After 12h of reaction, the reaction was removed, poured into 150mL of methanol and stirred for 5h, and the resulting precipitate was isolated by vacuum filtration and washed with excess methanol. The polymer was then redissolved in a minimum amount of DCM, poured again into 100mL of methanol and stirred for 2 h. The sample was taken at nuclear magnetic resonance to determine a conversion of 88.1%, and the product was collected again by vacuum filtration and dried under reduced pressure to give a white powder (M)_n＝19.8kDa，PDI＝1.16)。

Nuclear magnetic data for partial PXX catalyst

PXX 1:

¹H NMR(400MHz,CDCl₃)δ7.30(d,J＝9.2Hz,2H),7.09-7.08(m,4H),6.91(d,J＝ 9.2Hz,2H),6.64(t,J＝4.4Hz,2H).

PXX 2:

¹H NMR(400MHz,CDCl₃)δ7.30(d,J＝9.2Hz,2H),7.09-7.08(m,4H),6.91(d,J＝ 9.2Hz,2H),6.64(t,J＝4.4Hz,2H)

PXX 5:

¹H NMR(400MHz,CDCl₃)δ7.11(br,2H),7.06(t,2H,J＝7.8Hz),7.02(br,2H),6.61 (br,2H),2.70(t,4H,J＝7.4Hz),1.70-1.62(m,4H),1.47-1.38(m,4H),0.97(t,6H,J＝ 7.4Hz)

PXX 7:

¹H NMR(400MHz,C₆D₆)δ6.93(s,2H),6.90-6.83(m,4H),6.58(dd,J＝6.3,2.2Hz, 2H),2.69-2.61(m,4H),1.72-1.65(m,4H),1.40-1.20(m,20H),0.89(t,J＝9.2,4.5 Hz,6H).

PXX 12:

¹H NMR(400MHz,C₆D₆)δ7.02(d,J＝9.0Hz,2H),6.82(m,4H),6.70(d,J＝9.0Hz, 2H),2.53(t,J＝7.5Hz,4H),1.62-1.47(m,4H),1.28-1.07(m,20H),0.75(t,J＝6.8 Hz,6H).

PXX 14:

¹H NMR(400MHz,C₆D₆)δ7.02(d,J＝9.0Hz,2H),6.73(d,J＝9.0Hz,2H),6.70(s,2H), 6.39(s,2H),2.42(t,J＝7.7Hz,4H),1.55-1.40(m,4H),1.24-0.99(m,20H),0.74(t,J ＝6.8Hz,6H).

PXX 17:

¹H NMR(400MHz,CDCl₃)δ7.63(d,J＝7.6Hz,4H),7.47(t,J＝7.4Hz,4H),7.41(d,J＝ 7.2Hz,2H),7.35(s,2H),7.10-7.08(m,4H),6.57(d,J＝7.2Hz,2H)

PXX 22:

¹H NMR(400MHz,C₄D₈O)：δ6.93-6.95(d,J＝7.8Hz,2H),7.13-7.14(d,J＝9.3Hz, 2H),7.26-7.28(d,J＝8.3Hz,2H),7.54-7.56(d,J＝6.3Hz,2H),7.62-7.64(m,10H).

PXX 25:

¹H NMR(400MHz,C₄D₈O)δ1.15-1.18(t,J＝14.6Hz,6H),1.84-1.87(m,4H),2.81- 2.85(m,4H),6.90-6.92(d,J＝8.3Hz,2H),7.10-7.12(d,J＝9.8Hz,2H),7.23-7.25 (d,J＝8.3Hz,2H),7.45-7.47(d,J＝8.3Hz,4H),7.51-7.53(d,J＝8.3Hz,4H),7.62- 7.65(d,J＝10.0Hz,2H)。