A visible light-induced RAFT polymerization method using organic diselenide as initiator

Abstract

The present invention discloses a visible light induced RAFT polymerization method using an organic diselenide as an initiator, wherein an organic phase or aqueous phase homogeneous polymerization reaction system including a vinyl monomer, a diselenide initiator, and a chain transfer agent is configured, and a polymerization reaction is carried out under visible light irradiation to prepare a polymer. The present invention uses different types of organic diselenides as initiators, and successfully realizes visible light RAFT polymerization under room temperature and nitrogen conditions. The method has the advantages of being green, efficient, precise and controllable.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer synthesis and relates to a visible light induced RAFT polymerization method using organic diselenide as an initiator. Background Art

[0002] RAFT polymerization can be carried out under mild conditions and has a high tolerance for the functional groups of the reactants, so it is possible to synthesize polymers of various structures and molecular weights. This allows researchers to precisely control the properties of the polymer as needed and achieve customized polymer synthesis. The development of green and controllable RAFT polymerization is a challenging and promising research direction. Since selenium often exhibits high stability in compounds, this makes selenium-containing initiators have good stability during storage and use. Selenium-containing initiators start polymerization reactions by providing active sites or reducing the activation energy of the reaction, and are increasingly widely used in polymerization reactions. Traditional selenium free radical-initiated polymerization has poor controllability and low conversion rate, so it is very important to develop an efficient and controllable visible light-induced polymerization of diselenide. Summary of the invention

[0003] The technical problem to be solved by the present invention is to solve the deficiencies of the prior art, and to disclose a RAFT polymerization method with visible light control, room temperature and non-metal initiation by taking different types of diselenides as initiators.

[0004] Idea of ​​the invention: Free radical reaction has mild conditions and simple operation in organic synthesis and polymerization reactions, and has a wide range of applications. Most non-metal atoms can produce free radicals under certain conditions, especially oxygen-based elements including oxygen, sulfur, selenium, and tellurium. The bond energy of the diselenide bond Se-Se is only 172KJ / mol. It is a dynamic covalent bond, and its dynamic chemistry can be achieved under mild conditions of visible light. Selenium free radicals can be generated under visible light to initiate polymerization reactions. The introduction of RAFT chain transfer agents makes selenium free radicals more stable and the polymerization is effectively controlled. The combination of diselenide and polymers can be used for drug delivery and dynamic drug release, and also has the advantages of low production cost and simplified post-processing.

[0005] In order to solve the above technical problems, the present invention provides a visible light induced RAFT polymerization method using an organic diselenide as an initiator, comprising the following steps:

[0006] An organic phase or aqueous phase homogeneous polymerization reaction system including a vinyl monomer, a diselenide initiator, and a chain transfer agent is configured, and a polymerization reaction is carried out under visible light irradiation to prepare a polymer; wherein the diselenide initiator is (PhSe) 2 、(Gal-Se) 2 or (Gal-C 5 -Se) 2Any one of the above, wherein the diselenide initiator has the structural formula as shown below:

[0007]

[0008] Preferably, the vinyl monomer is any one of N,N-dimethylacrylamide, methacrylic acid, methyl methacrylate and dimethylaminopropyl methacrylamide.

[0009] The chain transfer agent is 2-(dodecyl trithiocarbonate)-2-methylpropionic acid or 2,2'-[methylthiobis(thio)]bis[2-methylpropionic acid].

[0010] The vinyl monomer is any one of N,N-dimethylacrylamide, methacrylic acid, methyl methacrylate and dimethylaminopropyl methacrylamide; the chain transfer agent is 2-(dodecyl trithiocarbonate)-2-methylpropionic acid or 2,2'-[methylthiobis(thio)]bis[2-methylpropionic acid].

[0011] The molar ratio of the vinyl monomer to the chain transfer agent and the diselenide initiator is 100-200:0.5-1:0.05-0.1, preferably 200:1:0.1.

[0012] Preferably, the organic phase is any one of tetrahydrofuran, dimethyl sulfoxide, dichloromethane, cyclohexane and ethyl acetate.

[0013] The wavelength of the visible light is 380-500nm, and the light intensity is 100-1000mW·cm -2 ; The polymerization reaction has a reaction temperature of room temperature and a reaction time of 1h-5h.

[0014] The polymerization reaction is carried out under an inert gas atmosphere. Preferably, the polymerization reaction is carried out under a nitrogen or helium atmosphere.

[0015] The molecular weight distribution of the polymer is 1.01 to 2.7.

[0016] Furthermore, the polymer prepared by the polymerization reaction of the present application is further used as a chain transfer agent of the system to carry out a chain extension reaction.

[0017] In some specific embodiments, when the vinyl monomer is N,N-dimethylacrylamide, the initiator is diphenyl diselenide, and the chain transfer agent is 2-(dodecyl trithiocarbonate)-2-methylpropionic acid, the polymer is recorded as PDMAA-I, and the structural formula of PDMAA-I is as follows:

[0018] Among them, n>80.

[0019] In some embodiments, when the vinyl monomer is N,N-dimethylacrylamide, the initiator is diphenyl diselenide, and the chain transfer agent is 2,2'-[methylthiobis(thio)]bis[2-methylpropionic acid], the polymer is recorded as PDMAA-II, and the structural formula of PDMAA-II is as follows:

[0020] Among them, n 1 +n 2 >103

[0021] In some embodiments, when the vinyl monomer is methacrylic acid, the initiator is diphenyl diselenide, and the chain transfer agent is 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, the polymer is recorded as PMAA-I, and the structural formula of PMAA-I is as follows:

[0022] Where n>148

[0023] In some embodiments, when the vinyl monomer is methacrylic acid, the initiator is diphenyl diselenide, and the chain transfer agent is 2,2'-[methylthiobis(thio)]bis[2-methylpropionic acid], the polymer is recorded as PMAA-Ⅱ, and the structural formula of PMAA-Ⅱ is as follows:

[0024] Among them, n 1 +n 2 >156.

[0025] In some examples, when the vinyl monomer is methyl methacrylate, the initiator is diphenyl diselenide, and the chain transfer agent is 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, the polymer is recorded as PMMA, and the structural formula of PMMA is as follows:

[0026] Where n>80

[0027] In some embodiments, when the vinyl monomer is dimethylaminopropyl methacrylamide, the initiator is diphenyl diselenide, and the chain transfer agent is 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, the polymer is recorded as PDMAPMA, and the structural formula of PDMAPMA is as follows:

[0028] Among them, n>119

[0029] In some embodiments, when the vinyl monomer is N,N-dimethylacrylamide, the initiator is diphenyl diselenide, the chain transfer agent is PMAA-I, the polymer is PMAA-b-PDMA, and the structure of PMAA-b-PDMA is as follows:

[0030] Where n>122, m>104

[0031] In some embodiments, when the vinyl monomer is methacrylic acid and the initiator is (Gal-Se) 2 When the chain transfer agent is 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, the polymer is recorded as PMAA-Ⅲ, and the structural formula of PMAA-Ⅲ is as follows:

[0032] Where n>120

[0033] In some embodiments, when the vinyl monomer is methacrylic acid and the initiator is (Gal-C 5 -Se) 2 When the chain transfer agent is 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropionic acid, the polymer is recorded as PMAA-IV, and the structural formula of PMAA-IV is as follows:

[0034] Among them, n>96

[0035] In some embodiments, the wavelength of the visible light is 380-500 nm, and the light intensity is 100-1000 mW·cm -2 .

[0036] In some embodiments, the polymerization reaction has a reaction temperature of room temperature and a reaction time of 1 h to 5 h.

[0037] In some embodiments, the polymerization reaction is performed under a nitrogen atmosphere.

[0038] In some embodiments, the molecular weight distribution of the polymer is 1.01 to 2.7, that is, M n / M w =1.01~2.7, the actual molecular weight of the obtained polymer is consistent with the theoretical molecular weight.

[0039] Beneficial effects: Compared with the prior art, this application has the following advantages:

[0040] (1) The present invention uses diselenide as an initiator to carry out RAFT polymerization, which can not only effectively control the polymerization reaction and synthesize a polymer with a precise molecular weight, but also diselenide can respond to hydrogen peroxide and glutathione in the biological environment, thereby changing the morphology and releasing the drug. Therefore, diselenide in the polymer plays an important role in macromolecular assembly and drug carrier.

[0041] (2) The present invention uses diselenide as an initiator and is applicable to a wide range of monomers, including water-soluble monomers and oil-soluble monomers, and a wide range of applicable solvents. It can not only successfully polymerize in organic solvents, but also achieve RAFT polymerization at room temperature and in aqueous phase. It has the advantages of room temperature oxygen resistance, green and efficient, and precise controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0043] Figure 1 Gal-C 5 -Se) 2 of 1 H NMR spectra;

[0044] Figure 2 Gal-C 5 -Se) 2 of 13 C NMR spectra;

[0045] Figure 3 Gal-C 5 -Se) 2 of 77 Se NMR spectra;

[0046] Figure 4 is the PDMAA-I in Example 1 of the present invention 1 H NMR spectra;

[0047] Figure 5 is a gel permeation chromatography (GPC) elution curve of PDMAA-I in Example 1 of the present invention;

[0048] Figure 6 is the MALDI-TOF-MS spectrum of PDMAA-I in Example 1 of the present invention;

[0049] Figure 7 This is a kinetic study diagram of PDMAA-I in Example 1 of the present invention;

[0050] Figure 8 is the PDMAA-II in Example 3 of the present invention 1 H NMR spectra;

[0051] Fig. 9 is the MALDI-TOF-MS spectrum of PDMAA-Ⅱ in Example 3 of the present invention;

[0052] Fig.10 is PMAA-Ib-PDMAA in Example 4 of the present invention 1H NMR spectra;

[0053] Fig.11 is a gel permeation chromatography (GPC) elution curve of PMAA-Ib-PDMAA in Example 4 of the present invention;

[0054] Fig.12 is PMAA-II in Example 5 of the present invention 1 H NMR spectra;

[0055] Fig.13 is a gel permeation chromatography (GPC) elution curve of PMAA-II in Example 5 of the present invention;

[0056] Fig.14 is PMMA in Example 6 of the present invention 1 H NMR spectra;

[0057] Fig.15 is the PDMAPMA in Example 7 of the present invention 1 H NMR spectra;

[0058] Fig.16 is PMAA-III in Example 8 of the present invention 1 H NMR spectra;

[0059] Fig.17 is a gel permeation chromatography (GPC) elution curve of PMAA-III in Example 8 of the present invention;

[0060] Fig.18 is PMAA-IV in Example 9 of the present invention 1 H NMR spectra;

[0061] Fig.19 This is a gel permeation chromatography (GPC) elution curve of PMAA-Ⅳ in Example 9 of the present invention. DETAILED DESCRIPTION

[0062] The following will describe the technical solutions in the embodiments of the present invention in detail in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] The monomer raw material N,N-dimethylacrylamide (DMAA) used in the embodiment of the present invention needs to be passed through a neutral alumina column to remove the inhibitor therein before use; wherein, the (Gal-Se) used in the embodiment 2Prepared by referring to the steps of Example 1 in Patent Publication No. ZL202310056891.1, (Gal-C 5 -Se) 2 It is composed of compound I in the patent and Na 2 Se 2 The reaction was prepared, and the steps were referred to Angew.Chem.Int.Ed.2019,58,9791–9796. Other reagents can be obtained from commercial channels and used directly. The specific preparation steps are as follows:

[0064]

[0065] Under nitrogen and ice bath conditions (0°C), selenium powder (0.19 g, 2.46 mmol), water (8.0 mL), sodium borohydride (NaBH 4 )(0.1672mg, 4.92mmol), react until the solution becomes clear and transparent, then remove the ice bath. Add selenium powder (0.19g, 2.46mmol) again, react at 50°C for 40min to generate a wine-red sodium diselenide solution. Add anhydrous tetrahydrofuran solution (10mL) of compound I (2,3,4,6-tetra-O-acetyl-α-D-brominated pyranose glucose) (1.63g, 3.28mmol) to the reaction solution and react at 50°C for 8h. After the reaction is completed, extract the reaction solution with ethyl acetate and water, and take the organic phase to obtain a yellow oil by rotary evaporation. Dissolve the yellow oil in methanol (2.0mL) and dichloromethane (4mL), then add sodium methoxide (0.04g, 0.7mmol), react at room temperature for 4h, adjust the reaction solution to neutral, and remove the solvent by rotary evaporation to obtain a yellow (Gal-C 5 -Se) 2 (0.162 g, 80.25% yield).

[0066] 1 H NMR(400MHz, Deuterium Oxide)δ4.83(d,J=3.6Hz,1H),3.89(dd,J=3.1,1.1Hz,1H),3.82(q,J=5.3,4.5Hz,1H),3.73(qd,J=10.3, 3.3Hz,2H),3.64(t,J=5.0Hz,3H),3.44(dt,J=9.8,6.2Hz,1H),2.91(t,J=7.3Hz,2H),1.77–1.35(m,6H); 13C NMR (110MHz, Deuterium Oxide) δ175.20,96.41,68.77,67.65,67.26,66.36,66.16,59.08,46.87,28.39,27.98,26.43,23.67,18.72; 77 Se NMR (76MHz, Deuterium Oxide) δ294.14; (see attached Figure 1-3 )

[0067] Other reagents were obtained from commercial sources and used directly.

[0068] The abbreviation of N,N-dimethylacrylamide used in the examples of the present invention is DMAA.

[0069] The abbreviation of methacrylic acid used in the examples of the present invention is MAA.

[0070] The abbreviation of methyl methacrylate used in the examples of the present invention is MMA.

[0071] The abbreviation of dimethylaminopropyl methacrylamide used in the examples of the present invention is DMAPMA.

[0072] The abbreviation of galactose diselenide-1 used in the embodiments of the present invention is (Gal-Se) 2

[0073] Galactose diselenide-2 used in the present invention is abbreviated as (Gal- 5 -Se) 2 .

[0074] The abbreviation of diphenyl diselenide used in the embodiments of the present invention is (PhSe) 2 .

[0075] The abbreviation of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropanoic acid used in the examples of the present invention is DDMAT.

[0076] The abbreviation of 2,2'-[methylthiobis(thio)]bis[2-methylpropionic acid] used in the examples of the present invention is bis-TTC.

[0077] The abbreviation of tetrahydrofuran used in the examples of the present invention is THF.

[0078] The sodium dodecyl sulfate used in the examples of the present invention is abbreviated as SDS.

[0079] The abbreviation of 2-(dodecyltrithiocarbonate)-2-methylpropanoic acid used in the examples of the present invention is DDMAT.

[0080] The abbreviation of 2,2'-[methylthiobis(thio)]bis[2-methylpropionic acid] used in the examples of the present invention is bis-TTC.

[0081] In the following embodiments of the present invention, the testing instruments and methods are as follows:

[0082] 1. NMR spectrum: Bruker 400MHz NMR spectrometer, with D 2 O or d 6 -DMSO was tested as a deuterated reagent.

[0083] 2. Monomer conversion rate: by testing the polymerization stock solution 1 H NMR spectra were determined using D 2 O or d 6 -DMSO as solvent.

[0084] 3. Number average molecular weight of polymer (M n , GPC) and molecular weight distribution (M w / M n ) value: determined by gel permeation chromatography (GPC), using a Waters Ultrahydrogel (300 x 7.8 mm) column, at 40 °C, 0.1 mol / L NaNO 3 Aqueous solution or DMSO or THF was used as the mobile phase with a flow rate of 1 mL / min. During data analysis, polyethylene glycol / polystyrene standards were used for calibration.

[0085] The structural formula of the polymer PDMAA-I described in the embodiment of the present invention is as follows:

[0086] Among them, n>80.

[0087] The structural formula of the polymer PDMAA-II described in the embodiment of the present invention is as follows:

[0088] Among them, n 1 +n 2 >103.

[0089] The structural formula of the polymer PMAA-Ⅰ described in the embodiment of the present invention is as follows:

[0090] Among them, n>80.

[0091] The structural formula of the polymer PMAA-II described in the embodiment of the present invention is as follows:

[0092] Among them, n 1 +n2 >156.

[0093] The structural formula of the polymer PMMA described in the embodiment of the present invention is as follows:

[0094] Among them, n>80.

[0095] The structural formula of the polymer PDMAPMA described in the embodiment of the present invention is as follows:

[0096] Among them, n>119.

[0097] The structural formula of the polymer PMAA-b-PDMA described in the embodiment of the present invention is as follows:

[0098] Among them, n>122,m>104.

[0099] The structural formula of the polymer PMAA-III described in the embodiment of the present invention is as follows:

[0100] Where n>120

[0101] The structural formula of the polymer PMAA-IV described in the embodiment of the present invention is as follows:

[0102] Among them, n>96.

[0103] Example 1: Preparation of PDMAA-I in THF.

[0104] (1) Preparation of PDMAA-I in THF

[0105] In molar ratio DMA:DDMAT:(PhSe) 2 =200:1:0.1, DMA (10 mmol, 1 mL), DDMAT (0.05 mmol, 18.23 mg), (PhSe) 2 (0.005 mmol, 1.56 mg), 0.5 mL THF was added to a 10 mL photoreaction tube with a dry magnet and heated at room temperature under nitrogen and 420 nm (184 mW·cm -2 ) was subjected to RAFT polymerization under light. After 5 h of reaction, the final reaction solution was dialyzed with water for 72 h (the water was changed every 8 h), and the product was recorded as PDMA-I. The product PDMA-I was placed in d 6 -Made in DMSO 1 H NMR test, GPC test of PDMA-I dissolved in THF, and MALDI-TOF-MS test of PDMA-I sample preparation.

[0106] (2) Characterization of PDMAA-I

[0107] (i) The obtained product PDMAA-I 1 H NMR images Figure 4 As shown, 1 H NMR results showed that in addition to the signals at 1.2–1.7 and 2.3–3.0 ppm attributed to the polymerization peaks of PDMAA-I, the weak signals at 0.8–1.0 ppm attributed to the methyl hydrogen of the terminal group could still be resolved, which confirmed the existence of active RAFT terminal groups on PDMAA-I. The conversion rate was 82.0%.

[0108] (ii) The GPC curve of PDMAA-I is as follows Figure 5 As shown, the GPC curve shows that the number average molecular weight of PDMAA-I is 10277 and the dispersity is 1.37.

[0109] (iii) The MALDI-TOF-MS spectrum of PDMAA-I is shown in Figure 6 As shown, MALDI-TOF-MS showed that the mass difference between the main peaks was about 99.13, which is the molecular weight of DMA.

[0110] In summary, the above characterization results confirmed that the RAFT polymerization of DMA was initiated by the cleavage of diselenide under visible light.

[0111] (3) Kinetic studies

[0112] At the 1st, 2nd, 3rd, 4th and 5th hour of the PDMA polymerization reaction (the RAFT polymerization reaction in "(1) Preparation of PDMA-I in THF" of this Example), samples were taken in DMSO and 1 The DMA monomer conversion rate was tested by H NMR, and the molecular weight and molecular weight distribution of PDMA-I were tested by GPC. The experimental results are as follows: Figure 7 shown.

[0113] Depend on Figure 7 (a) It can be seen that the conversion rate of the obtained polymer PDMA-I increases with the increase of polymerization time.

[0114] Depend on Figure 7 (b) It can be seen that at high conversion rates, ln([M] 0 / [M] t ) and polymerization time were fitted with a very satisfactory linear fit, indicating that the system follows pseudo-first-order kinetics, indicating that the polymerization is controllable.

[0115] (4) Change the molar ratio of DMA:DDMAT:(PhSe) 2 =50:1:0.1

[0116] Molar ratio Molar ratio DMA:DDMAT:(PhSe) 2 =50:1:0.1, DMA (2.5mmol, 250μL), DDMAT (0.05mmol, 18.23mg), (PhSe) 2 (0.005 mmol, 1.56 mg), 0.5 mL THF was added to a 10 mL photoreaction tube with a dry magnet and heated at room temperature under nitrogen and 420 nm (184 mW·cm -2 ) was subjected to RAFT polymerization under light, and the product obtained after 1 hour of reaction was PDMA-I. The product PDMA-I was placed in d 6 -Made in DMSO 1 H NMR test showed that the conversion rate was 13.7%.

[0117] (5) Change the molar ratio of DMA:DDMAT:(PhSe) 2 =200:1:0.3

[0118] Molar ratio Molar ratio DMA:DDMAT:(PhSe) 2 =200:1:0.3, DMA (10 mmol, 1 mL), DDMAT (0.05 mmol, 18.23 mg), (PhSe) 2 (0.015 mmol, 4.68 mg), 0.5 mL THF was added to a 10 mL photoreaction tube with a dry magnet and heated at room temperature under nitrogen and 420 nm (184 mW·cm -2 ) was subjected to RAFT polymerization under light. After 1 h of reaction, the product obtained was recorded as PDMA-I. The product PDMA-I was placed in d 6 -Made in DMSO 1 H NMR test showed that the conversion rate was 17.2%.

[0119] After changing the molar ratio of monomer, CTA and initiator, the conversion rate of the obtained product was low. Therefore, in the DMA:DDMAT:(PhSe) 2 =200:1:0.1, the conversion rate of the obtained product is optimal.

[0120] Example 2: Preparation of PDMAA-I in water.

[0121] Molar ratio Molar ratio DMA:DDMAT:(PhSe) 2 =200:1:0.1, DMA (10 mmol, 1 mL), DDMAT (0.05 mmol, 18.23 mg), (PhSe) 2(0.005mmol, 1.56mg), 2.3mg SDS was dissolved in 1mL water, added into a 10mL photoreaction tube with a dry magnet, and heated at room temperature, nitrogen, 420nm (184mW·cm -2 ) was subjected to RAFT polymerization under light. After 1 h of reaction, the product obtained was recorded as PDMA-I. The product PDMA-I was placed in d 6 -Made in DMSO 1 H NMR test showed that the conversion rate was 47.8%.

[0122] Example 3: Preparation of PDMAA-II in THF.

[0123] In molar ratio DMAA:bis-TTC:(PhSe) 2 =200:1:0.1, DMA (10 mmol, 1 mL), bis-TTC (0.05 mmol, 14.12 mg), (PhSe) 2 (0.005 mmol, 1.56 mg), 0.5 mL THF was added to a 10 mL photoreaction tube with a dry magnet and heated at room temperature under nitrogen and 420 nm (184 mW·cm -2 ) was subjected to RAFT polymerization under light. After 1 h of reaction, the product obtained was recorded as PDMA-II. The product PDMA-II was placed in DMSO for 1 H NMR test, GPC test of PDMA-II dissolved in THF, and MALDI-TOF-MS test of PDMA-II sample preparation.

[0124] PDMAA-II 1 H NMR results are as follows Figure 8 As shown, the conversion rate was 51.8%.

[0125] The MALDI-TOF-MS spectrum of PDMAA-II is shown in Fig. 9 As shown, MALDI-TOF-MS showed that the mass difference between the adjacent main peaks was about 99.13, which is the molecular weight of DMA.

[0126] Example 4: In-situ chain extension experiment.

[0127] (1) Preparation of PMAA-Ⅰ in THF

[0128] In molar ratio MAA:DDMAT:(PhSe) 2 =200:1:0.1, MAA (10 mmol, 0.848 mL), DDMAT (0.05 mmol, 18.23 mg), (PhSe) 2(0.005 mmol, 1.56 mg), 0.5 mL THF was added to a 10 mL photoreaction tube with a dry magnet and heated at room temperature under nitrogen and 420 nm (184 mW·cm -2 ) was subjected to RAFT polymerization under light. After 1 h of reaction, the product was recorded as PMAA-Ⅰ. The product PMAA-Ⅰ was placed in DMSO for 1 H NMR test (conversion rate 61.0%), GPC test of PMAA-I dissolved in THF, and MALDI-TOF-MS test of PMAA-I sample preparation.

[0129] (2) Chain extension of PMAA-Ⅰ

[0130] The same amounts of all reagents as in the original reaction in Example "(1) Preparation of PMAA-I in THF" (excluding DDMAT), namely DMA (10 mmol, 1 mL), (PhSe) 2 (0.005 mmol, 1.56 mg), 0.5 mL THF and PMAA-I prepared under “(1) Preparation of PMAA-I in THF” were mixed for chain extension and heated at room temperature under nitrogen and 380-500 nm (100-1000 mW·cm -2 ) was used for RAFT polymerization under light. After 2 h of reaction, the reaction solution was sampled and placed in DMSO for 1 H NMR analysis, GPC analysis was performed by diluting in THF.

[0131] 1 H NMR Fig.10 As shown in Figure 1, there are polymerization peaks of PMAA and PDMA, indicating that the chain extension is successful and the conversion rate is 52.3%. Fig.11 As shown, the black peak is the GPC curve of PMAA-I before chain extension, with a number average molecular weight of 89488 and a dispersity of 1.98; the red peak is the GPC curve of PMAA-I after chain extension, with a number average molecular weight of 176612 and a dispersity of 2.64 (Note: the product after chain extension is recorded as PMAA-b-PDMA, and no additional chain transfer agent is required after the chain extension experiment. PMAA-I acts as a chain transfer agent in the chain extension experiment). The experimental results show that PMAA-I has achieved successful chain extension, and the GPC curve before and after chain extension has obvious displacement and the peak shape has almost no change, indicating the active characteristics of the polymerization system.

[0132] Example 5: Preparation of PMAA-II in THF.

[0133] In molar ratio MAA:bis-TTC:(PhSe) 2=200:1:0.1, MAA (10 mmol, 0.848 mL), bis-TTC (0.05 mmol, 14.12 mg), (PhSe) 2 (0.005 mmol, 1.56 mg), 0.5 mL THF was added to a 10 mL photoreaction tube with a dry magnet and heated at room temperature under nitrogen and 420 nm (184 mW·cm -2 ) was subjected to RAFT polymerization under light, and the product obtained after 2 h was recorded as PMAA-II. The product PMAA-II was placed in DMSO for 1 H NMR test, PMAA-II was dissolved in THF for GPC test.

[0134] PMAA-II 1 H NMR results are as follows Fig.12 As shown, the conversion rate was 78.0%.

[0135] The GPC curve of PMAA-II is as follows Fig.13 As shown, the number average molecular weight of PMAA-II is 111122 and the dispersity is 2.05.

[0136] Example 6: Preparation of PMMA in THF

[0137] MMA in molar ratio: bis-TTC: (PhSe) 2 =200:1:0.1, respectively, MMA (10 mmol, 1 mL), DDMAT (0.05 mmol, 18.23 mg), (PhSe) 2 (0.005 mmol, 1.56 mg), 0.5 mL THF was added to a 10 mL photoreaction tube with a dry magnet and heated at room temperature under nitrogen and 420 nm (184 mW·cm -2 ) was subjected to RAFT polymerization under light. After 3 h of reaction, the product was recorded as PMMA. The product PMMA was placed in DMSO for 1 H NMR test.

[0138] PMMA 1 H NMR results are as follows Fig.14 As shown, the conversion rate was 40.0%.

[0139] Example 7: Preparation of PDMAPMA in THF.

[0140] In molar ratio DMAPMA:DDMAT:(PhSe) 2 =200:1:0.1, DMAPMA (10 mmol, 1 mL), DDMAT (0.05 mmol, 18.23 mg), (PhSe)2 (0.005 mmol, 1.56 mg), 0.5 mL THF was added to a 10 mL photoreaction tube with a dry magnet and heated at room temperature under nitrogen and 420 nm (184 mW·cm -2 ) was subjected to RAFT polymerization under light. After 3 h of reaction, the final reaction solution was precipitated in ether to obtain a product named PDMAPMA. The product PDMAPMA was placed in DMSO for 1 HNMR test.

[0141] PDMAPMA 1 H NMR results are as follows Fig.15 As shown, the conversion rate was 59.8%.

[0142] Example 8: Preparation of PMAA-III in THF.

[0143] Molar ratio MAA:DDMAT:(Gal-Se) 2 =200:1:0.1, MAA (10 mmol, 0.848 mL), DDMAT (0.05 mmol, 18.23 mg), (Gal-Se) 2 (0.005 mmol, 4.1 mg), 0.5 mL THF was added to a 10 mL photoreaction tube with a dry magnet and heated at room temperature under nitrogen and 420 nm (184 mW·cm -2 ) was subjected to RAFT polymerization reaction under light. After 2 h of reaction, the product was recorded as PMAA-Ⅲ. The product PMAA-Ⅲ was placed in d 6 --Performed in DMSO 1 H NMR test, GPC test of PMAA-Ⅲ dissolved in THF, and MALDI-TOF-MS test of PMAA-Ⅲ sample preparation.

[0144] PMAA-III 1 H NMR results are as follows Fig.16 As shown, the conversion rate was 60.0%.

[0145] The GPC curve of PMAA-Ⅲ is as follows Fig.17 As shown, the number average molecular weight of PMAA-III is 111271 and the dispersity is 2.32.

[0146] Example 9: Preparation of PMAA-IV in THF.

[0147] In molar ratio MAA:DDMAT:(Gal-C 5 -Se) 2=200:1:0.1, MAA (10 mmol, 0.848 mL), DDMAT (0.05 mmol, 18.23 mg), (Gal-C 5 -Se) 2 (0.005 mmol, 4.97 mg), 0.5 mL THF was added to a 10 mL photoreaction tube with a dry magnet and heated at room temperature under nitrogen and 420 nm (184 mW·cm -2 ) was subjected to RAFT polymerization under light. After 2 h of reaction, the product was recorded as PMMA-Ⅳ. The product PMMA-Ⅳ was placed in DMSO for 1 H NMR test, PMMA-IV was dissolved in THF for GPC test.

[0148] PMMA-Ⅳ 1 H NMR results are as follows Fig.18 As shown, the conversion rate was 48.0%.

[0149] The GPC curve of PMMA-Ⅳ is as follows Fig.19 As shown, the number average molecular weight of PDMA-II is 122613 and the dispersity is 1.91.

[0150] The present invention provides a method and idea for visible light-induced RAFT polymerization of diselenide. There are many methods and approaches to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A visible light induced RAFT polymerization method using an organic diselenide as an initiator, characterized in that: The steps include: An organic phase or aqueous phase homogeneous polymerization reaction system including a vinyl monomer, a diselenide initiator, and a chain transfer agent is configured, and a polymerization reaction is carried out under visible light irradiation to prepare a polymer; wherein the diselenide initiator is any one of (PhSe)2, (Gal-Se)2 or (Gal-C5-Se)2, and the structural formula of the diselenide initiator is as follows: The vinyl monomer is any one of N,N-dimethylacrylamide, methacrylic acid, methyl methacrylate and dimethylaminopropyl methacrylamide; the chain transfer agent is 2-(dodecyl trithiocarbonate)-2-methylpropionic acid or 2,2'-[methylthiobis(thio)]bis[2-methylpropionic acid]; the molar ratio of the vinyl monomer to the chain transfer agent and the diselenide initiator is 100-200:0.5-1:0.05-0.

1.

2. The method according to claim 1, characterized in that The organic phase is any one of tetrahydrofuran, dimethyl sulfoxide, dichloromethane, cyclohexane and ethyl acetate.

3. The method according to claim 1, characterized in that The wavelength of the visible light is 380-500 nm, and the light intensity is 100-1000 mW•cm -2 ; The reaction temperature of the polymerization reaction is room temperature, and the reaction time is 1h-5h.

4. The method according to claim 1, characterized in that: The polymerization reaction is carried out under an inert gas atmosphere.

5. The method according to claim 1, characterized in that The molecular weight distribution of the polymer is 1.01-2.

7.

6. The method according to any one of claims 1 to 5, characterized in that: The polymer prepared by the polymerization reaction is further used as a chain transfer agent in the system to carry out a chain extension reaction.

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