Anionic-cationic pair type amino bisphenol oxy alkali metal complex, and preparation method and application thereof

Abstract

The application discloses a kind of cation-anion pair type amino bisphenol oxy alkali metal complex (I) and its preparation method and application in high activity, high selectivity catalytic lactone ring-opening polymerization.Therein, the preparation method includes the following steps: neutral ligand is reacted with metal hydride, quaternary ammonium salt in organic medium, is filtered, concentrated, recrystallized to obtain target compound.Cation-anion pair type amino bisphenol oxy alkali metal complex of the application is a kind of high-efficiency lactone ring-opening polymerization catalyst, especially for racemic lactide can obtain high stereoregularity polylactide.Cation-anion pair type amino bisphenol oxy alkali metal complex of the application, obvious advantage: raw material is easy to obtain, synthesis route is simple, product yield is high;It has high catalytic activity and stereoselectivity to lactone polymerization, obtains high stereoregularity, high molecular weight polyester material, can satisfy the needs of industrial department.A has the structure shown in the following, is coordinated with metal center M by nitrogen atom:

Description

Technical Field

[0001] This invention relates to a class of anionic and cationic para-aminobisphenol oxyalkali metal complexes, their preparation methods, and the application of such complexes in lactone polymerization. Background Technology

[0002] Polyolefin materials are stable in performance, but they are difficult to degrade and easily cause environmental pollution. Furthermore, their raw materials are small-molecule olefins produced by non-renewable petroleum cracking. Therefore, finding biodegradable polymers to replace polyolefin materials is of great significance. Polylactide (PLA) has advantages such as biocompatibility and biodegradability, and also possesses semi-crystalline properties similar to polyethylene and polypropylene. It has promising applications in fields such as biology, medicine, and food packaging, and has become one of the research hotspots in green materials development in recent years.

[0003] Lactose contains two chiral centers and exists in three isomers: meso-LA, L-LA, and D-LA; a mixture of equal proportions of L- and D-LA is called racemic-LA. Catalytic polymerization of lactose with different configurations can yield polylactide with various microstructures, and these different microstructures result in different physical properties and applications. Ring-opening polymerization of single-configuration L-lactide or D-lactide yields isotactic polylactide (PLLA, PDLA), which exhibits good heat resistance and thermal stability, a high melting point (170-180℃), and good mechanical strength, and is commonly used as a bone fixation material. Atactic polylactide (PCL) can be obtained by catalyzing the polymerization of meso or racemic lactide using non-stereoselective catalysts, and is commonly used as a drug delivery system. Conversely, syndiotactic, heterotactic, and isotactic PCL can be obtained by catalyzing the polymerization of meso or racemic lactide using stereoselective catalysts. Isotactic PCL, obtained from the isotactic selective polymerization of racemic lactide, often possesses a stereoblock structure, a high melting point, and superior physical and mechanical properties compared to conventional PCL. Furthermore, alkali metals are biocompatible, inexpensive, and readily available, making them suitable as metal centers for catalysts, which aligns with the application requirements of PCL in biomedicine and other fields. Therefore, developing highly active, highly isotactic stereoselective alkali metal complexes for the controlled synthesis of high-performance PCL is of great significance.

[0004] In 2011, Davidson's group discovered that aryloxy sodium complexes with tris(2-dimethylaminoethyl)amine as ligands exhibited high catalytic activity for the polymerization of racemic lactide, with relatively controllable polymerization, but yielded random polymers (Inorg. Chem. 2011, 50, 3589–3595). In 2015, Cano's group synthesized imine phenoxy alkali metal complexes, among which the potassium complex showed very high catalytic activity for the ring-opening polymerization of racemic lactide but lacked stereoselectivity, while the lithium complex exhibited lower activity but showed partial heteroractic selectivity.r =0.62-0.75 (Organometallics 2015, 34, 477–487). In 2014, Wu's group synthesized a purine monophenoloxy potassium complex containing a crown ether structure. This complex exhibits high catalytic activity for the polymerization of racemic lactide, achieving isotactic selectivity of P at -60°C. m =0.86, marking the first instance of an alkali metal complex exhibiting high isotactic selectivity for rac-LA polymerization (Macromolecules 2014, 47, 7789–7796). In 2015, Wu's group synthesized a potassium phenoxy complex with a crown ether structure as an auxiliary ligand and triphenylmethyl substitution. This complex exhibited low activity for the ring-opening polymerization of racemic lactide, but high isotactic selectivity, reaching P0.86. m =0.89; and it has strong tolerance to impurities, capable of catalyzing 1000 equivalent rac-LA polymerization at room temperature (Catal. Sci. Technol., 2016, 6, 515-520). In the same year, Wu's group synthesized a potassium phenoxy complex with anthracene ring substitution and crown ether structure as an auxiliary ligand. This complex exhibited lower polymerization activity but very high isotactic selectivity, reaching P... m =0.94 (Inorg. Chem. 2016, 55, 136–143). As shown above, crown ether ligands play a crucial role in the catalytic isotactic selective polymerization of sodium and potassium complexes in rac-LA, but crown ethers are toxic and unsuitable for industrial production. To overcome the limitations of using crown ethers, in 2019, Wu's group synthesized for the first time a sodium complex with a phenylenediamine-bridging backbone, Salen ligand. However, this series of complexes exhibits low activity in the polymerization of racemic lactide and only shows meso-isotactic selectivity. m =0.82 (Inorg. Chem. 2019, 58, 218–227). Subsequently, Wu's group synthesized tetradentate aminobisphenoloxy sodium complexes, a series of complexes that can catalyze 1000 equivalents of rac-LA polymerization with isotactic selectivity up to P. m =0.82, the polymer molecular weight can reach 50.9 kg / mol, and the molecular weight distribution is narrow (Chem. Asian J. 2019, 14, 662–669). In 2022, Wu's group synthesized a chelating effect of biphenyl bisphenoloxy potassium complex for the ring-opening polymerization of racemic lactide. It has low catalytic activity and isotactic selectivity. m =0.84 (J. Polym. Sci., 2022, 60, 2847).

[0005] Currently, most alkali metal complex catalysts exhibiting high isotactic selectivity for the ring-opening polymerization of racemic lactide contain crown ethers as auxiliary ligands. While they achieve the highest isotactic selectivity at low temperatures, their polymerization activity is low at these conditions, and the crown ethers are toxic, making them unsuitable for industrial production. Alkali metal complexes without crown ethers as auxiliary ligands exhibit only moderate to isotactic selectivity for the polymerization of racemic lactide at low temperatures. Therefore, there is a need to further develop high isotactic selectivity alkali metal complex catalysts without crown ether coordination to promote their industrial application. The cationic and anionic para-aminobisphenol oxyalkali metal complexes disclosed in this invention, without crown ethers as auxiliary ligands, exhibit high isotactic selectivity and high catalytic activity at low temperatures. Summary of the Invention

[0006] One of the objectives of this invention is to disclose a class of anionic and cationic para-aminobisphenol alkali metal complexes.

[0007] The second objective of this invention is to disclose a method for preparing a class of anionic and cationic para-aminobisphenol alkali metal complexes.

[0008] The third objective of this invention is to disclose the application of a class of anionic and cationic para-aminobisphenol oxyalkali metal complexes in lactone polymerization.

[0009] The technical concept of this invention is as follows: Aminobisphenol ligands are characterized by readily available raw materials, simple synthesis, and tunable structure. By changing the substituents, electronic and steric effects can be adjusted, effectively controlling the catalytic activity and stereoselectivity of metal complexes. However, when used in the synthesis of alkali metal complexes, they are easily dianionized after deprotonation, resulting in binuclear complexes. If additional cations are used to stabilize excess ligand anions, it is hoped that mononuclear alkali metal complexes can be obtained using aminobisphenol ligands. Currently, ionic aminobisphenol oxy-containing complexes have not been studied in the stereoselective polymerization of racemic lactide. This invention will provide a class of anionic and cationic para-type aminobisphenol oxy-containing alkali metal complexes. By changing the structure of the nitrogen-containing heterocyclic rings substituted in the ligands and the ortho- and para-substituents of the phenoloxy groups, the Lewis acidity of the metal center and the steric hindrance around the metal center can be adjusted, aiming to achieve highly active and highly isotactic stereoselective catalytic ring-opening polymerization of racemic lactide using alkali metal complexes.

[0010] The anionic and cationic para-aminobisphenol alkali metal complex (I) provided by the present invention is characterized by having the following general formula:

[0011]

[0012] In formula (I):

[0013] R 1 ~R 2 Representing C1 to C respectively20 Alkyl groups with straight, branched, or cyclic structures, C7–C6 30 Mono- or polyaryl substituted alkyl groups, C6–C 18 aryl, or halogen; R 3 Representing C1 to C 10 Alkyl groups with straight, branched, or cyclic structures;

[0014] A is a group having a structure as shown in formula (II), (III), (IV), (V) or (VI):

[0015]

[0016] A coordinates with the metal center M through its nitrogen atom; M represents Na and K.

[0017] In formula (I):

[0018] R 1 ~R 2 Preferably C1 to C 12 Alkyl groups with straight, branched, or cyclic structures, C7–C6 20 Mono- or polyaryl substituted alkyl groups, C6–C 12 aryl, or halogen; R 3 Preferably, it is an alkyl group with a C1-C6 straight chain, branched chain, or cyclic structure;

[0019] Option A is preferred:

[0020]

[0021] More characteristically, in equation (I),

[0022] R 1 ~R 2 Preferably, it contains methyl, isopropyl, tert-butyl, cumyl, triphenylmethyl, phenyl, or halogen; R 3 The preferred compounds are methyl, ethyl, isopropyl, and n-butyl.

[0023] The preferred structure of the anionic and cationic para-aminobisphenol alkali metal complex is as follows:

[0024]

[0025]

[0026] Preferred anionic and cationic para-aminobisphenol alkali metal complexes typically have the following structures for their aminobisphenol ligands:

[0027]

[0028] The preparation method of the anionic and cation-type aminobisphenol alkali metal complex (I) of the present invention includes the following steps:

[0029]

[0030]

[0031] Ethylenediamine is reacted with an aldehyde-substituted nitrogen-containing heterocyclic compound of formula (VIII), and reduced with a reducing agent to generate the corresponding di-secondary amine. Then, 2-bromomethyl-4,6-disubstituted phenol (IX) is added and reacted at a temperature of 0–90 °C for 2–72 hours. The aminobisphenol ligand compound (VII) is then collected from the reaction product. Alternatively, diethyl oxalate is reductively amination reaction with a primary amine of formula (X) to generate the corresponding di-secondary amine. Then, 2-bromomethyl-4,6-disubstituted phenol (IX) is added and reacted at a temperature of 0–90 °C for 2–72 hours. The aminobisphenol ligand compound (VII) is then collected from the reaction product.

[0032] In the above preparation method, the reducing agent is a common reducing agent in organic reactions, such as sodium borohydride or lithium aluminum hydride.

[0033] Optionally, the aminobisphenol ligand compound shown in formula (VII) is reacted with a metal hydride in an organic medium, followed by the addition of a quaternary ammonium salt [NR]. 3 4]X continued to react at a temperature of 0–100 °C for 2–24 hours, and then the anionic and cation-type aminobisphenol alkali metal target complex (I) was collected from the reaction product.

[0034] In the above preparation method, the substituent R 1 ~R 2 A and the corresponding groups of the anionic and cation-type aminobisphenol alkali metal complex (I) satisfying the present invention are consistent; the metal hydride MH is NaH, KH; the quaternary ammonium salt [NR 3 In X, R 3 Consistent with the respective groups of the anionic and cation-type aminobisphenol alkali metal complex (I) satisfying the present invention, X is Cl, Br, I or OH.

[0035] Aminobisphenol ligand compounds (VII) with metal hydrides and quaternary ammonium salts [NR] 3 4] The molar ratio of X is 1:2.0~3.0:0.8~1.5, preferably 1:2.2~2.5:0.9~1.2.

[0036] The organic medium is selected from one or two of tetrahydrofuran, diethyl ether, toluene, benzene, petroleum ether, and n-hexane.

[0037] The anionic and cationic para-aminobisphenol alkali metal complexes described in this invention are highly efficient lactone polymerization catalysts that can be used for the polymerization of L-lactide, D-lactide, rac-lactide, and meso-lactide, in the form of solution polymerization and melt polymerization.

[0038] Using the cationic and anionic para-aminobisphenol alkali metal complexes of the present invention as catalysts, lactide is polymerized at -70 to 180°C, preferably -70 to 140°C, and most preferably -70 to 50°C; the molar ratio of catalyst to monomer during polymerization is 1:1 to 10000, preferably 1:20 to 5000, and most preferably 1:100 to 3000.

[0039] Using the cationic and anionic para-aminobisphenol alkali metal complexes of the present invention as catalysts, a certain amount of alcohol can be added as a chain transfer agent to regulate the molecular weight of the resulting polymer during the catalytic polymerization of lactones. The molar ratio of catalyst to alcohol and lactide monomer during polymerization is 1:1–50:1–10000, preferably 1:1–20:20–5000, and most preferably 1:1–10:100–3000; the alcohol is C1–C6. 10 Alkyl alcohols with straight-chain, branched, or cyclic structures, C7–C6 20 Mono- or polyaryl substituted alkyl alcohols, preferably isopropanol or benzyl alcohol.

[0040] Using the cationic and anionic para-aminobisphenol alkali metal complexes of the present invention as catalysts, solvents may also be included in the catalytic polymerization of lactones. The solvents are preferably one or more of toluene, tetrahydrofuran, dichloromethane, n-hexane, petroleum ether, m-xylene, o-xylene, mesitylene, and trichlorobenzene. Specifically, there may be one, two, three, four, or five solvents.

[0041] The catalyst provided by this invention is easy to prepare and has stable properties. Furthermore, the catalyst exhibits high catalytic activity and stereoselectivity in the ring-opening polymerization of lactide, and highly isotactic selective polymerization can be achieved by controlling the ligand structure and polymerization conditions. The invention is further illustrated below with specific embodiments, but is not limited thereto. Detailed Implementation

[0042] Example 1

[0043] Synthesis of ligand L1:

[0044] (1) Synthesis of N,N'-di[(pyridin-2-yl)-methyl]ethylenediamine

[0045]

[0046] 25 mL of methanol, 10 mmol (0.60 g) of ethylenediamine, and 20.0 mmol (2.14 g) of pyridine-2-carboxaldehyde were added to a 50 mL three-necked flask. The mixture was reacted in an oil bath at 70 °C for 10 h. After cooling to room temperature, sodium borohydride (30.0 mmol (1.13 g) was added in a water bath, and the reaction was continued in an oil bath at 70 °C for 12 h. The reaction was quenched with saturated potassium carbonate solution, extracted with dichloromethane, dried over anhydrous Na₂SO₄, and the solvent was removed under reduced pressure to give a brown oily substance (2.32 g, yield approximately 96%).

[0047] (2) Synthesis of ligand L1

[0048]

[0049] To a 50 mL flask containing N,N'-di[(pyridin-2-yl)-methyl]ethylenediamine (approximately 9.21 mmol, 2.24 g), 20 mL of dichloromethane, triethylamine (57.4 mmol, 5.81 g), and 2-bromomethyl-4,6-di-tert-butylphenol (18.4 mmol, 5.51 g) were added. The reaction was allowed to proceed at room temperature for 12 h, quenched with water, extracted with dichloromethane, dried over anhydrous Na₂SO₄, and the solvent was removed under reduced pressure. 30 mL of methanol was added, and the mixture was stirred for 12 h. The mother liquor was then decanted, and the solution was dried under vacuum to obtain a milky white powder (5.66 g, 90.4%). 1 H NMR (400MHz, CDCl3, 298K) δ10.47 (s, 2H, OH), 8.50 (d, 3 J = 4.8 Hz, 2H, ArH), 7.58 (td, 3 J = 7.7, 1.7 Hz, 2H, ArH), 7.23 (d, 3 J = 7.8 Hz, 2H, ArH), 7.18 (d, 4 J = 2.2 Hz, 2H, ArH), 7.13 (dd, 3 J = 6.7, 5.0 Hz, 2H, ArH), 6.79 (d, 4 J=2.2Hz,2H,ArH),3.70(s,8H,NCH2Ar,),2.81(s,4H NCH2CH2N),1.39(s,18H,C(CH3)3),1.25(s,18H),C(CH3)3.Anal.Calcd.for C 44 H 62 N4O2: C, 77.83; H, 9.20; N, 8.25. Found: C, 77.85; H, 9.25; N, 8.24%.

[0050] Example 2

[0051] Synthesis of ligand L2

[0052]

[0053] Except for the use of N,N'-di[(pyridin-2-yl)-methyl]ethylenediamine (approximately 10 mmol, 2.42 g), triethylamine (60 mmol, 6.07 g), and 2-bromomethyl-4-chloro-6-tert-butylphenol (20.0 mmol, 5.55 g) as raw materials, the other operations were the same as in Example 1, yielding a pale yellow solid (2.57 g, 40.5%). 1 H NMR(400MHz,CDCl3)δ10.82(br s,2H,OH),8.54(d, 3 J = 4.8 Hz, 2H, ArH), 7.61 (td, 3 J=7.7,1.8Hz,2H,ArH),7.21–7.13(m,4H,ArH),7.12(d, 4 J = 2.6 Hz, 2H, ArH), 6.75 (d, 4 J=2.6Hz,2H,ArH),3.69(s,4H,NCH2Ar),3.64(s,4H,NCH2Ar),2.73(s,4H,NCH2CH2N),1.36(s,18H,C(CH3)3). 13 C NMR (101MHz, CDCl3) δ157.10,155.22,149.25,138.68,136.85,126.88,126.39,12 3.79,123.61,123.01,122.60,59.16,58.04,50.13,35.03,29.34.Anal.Calcd.for C 36 H 44 Cl2N4O2: C, 68.02; H, 6.98; N, 8.81. Found: C, 68.01; H, 6.87; N, 8.74%.

[0054] Example 3

[0055] Synthesis of ligand L3

[0056]

[0057] Except for the use of N,N'-di[(pyridin-2-yl)-methyl]ethylenediamine (approximately 10 mmol, 2.42 g), triethylamine (60 mmol, 6.07 g), and 2-bromomethyl-4-tert-butyl-6-phenylphenol (20.0 mmol, 6.38 g) as raw materials, the other operations were the same as in Example 1, yielding a pale yellow solid (4.26 g, 59.34%). 1H NMR (400MHz, CDCl3) δ 8.48 (d, 3 J = 4.8, 2H, ArH), 7.55(dt, 3 J=7.8,1.5Hz,4H,ArH),7.50(td, 3 J=7.7,1.7Hz,2H,ArH),7.42–7.34(m,4H,ArH),7.29(td, 3 J = 7.4, 1.4 Hz, 2H, ArH), 7.23 (t, 4 J=2.1Hz,2H,ArH),7.17–7.07(m,4H,ArH),6.94(t, 4 J=2.1Hz,2H,ArH),3.80(s,4H,NCH2Ar),3.77(s,4H,NCH2Ar),2.84(s,4H,NCH2CH2N),1.28(s,18H,C(CH3)3). 13 C NMR (101MHz, CDCl3) δ156.99,155.11,149.15,138.58,136.74,126.78,126.28,123.6 9,123.51,122.90,122.49,59.06,57.94,50.03,38.56,34.92,29.23.Anal.Calcd.for C 48 H 54 N4O2:C,80.19;H,7.57;N,7.79.Found:C,80.11;H,7.77;N,7.77%.

[0058] Example 4

[0059] Synthesis of ligand L4

[0060] (1) Synthesis of N,N'-di[(quinolin-2-yl)-methyl]ethylenediamine

[0061]

[0062] Except for the use of ethylenediamine (10 mmol, 0.60 g), quinoline-2-carboxaldehyde (20.0 mmol, 3.14 g), and sodium borohydride (31.0 mmol, 1.18 g) as raw materials, the other operating steps were the same as in Example 1. A red oily substance (3.44 g, yield approximately 100%) was obtained.

[0063] (2) Synthesis of ligand L4

[0064]

[0065] Except for the use of N,N'-di[(quinolin-2-yl)-methyl]ethylenediamine (approximately 10 mmol, 3.44 g), triethylamine (60 mmol, 6.07 g), and 2-bromomethyl-4,6-di-tert-butylphenol (20.0 mmol, 5.98 g) as raw materials, the other operations were the same as in Example 1, yielding a pale yellow solid (6.42 g, 82.4%). 1 H NMR(400MHz,CDCl3)δ10.70(br s,2H,OH),8.09(d, 3 J = 8.4 Hz, 2H, ArH), 7.94 (d, 3 J = 8.5 Hz, 2H, ArH), 7.72 (d, 3 J = 8.1 Hz, 2H, ArH), 7.67 (t, 3 J = 7.1 Hz, 2H, ArH), 7.49 (t, 3 J = 7.5 Hz, 2H, ArH), 7.25 (d, 3 J = 8.4 Hz, 2H, ArH), 7.19 (d, 4 J = 2.3 Hz, 2H, ArH), 6.80 (d, 4 J=2.2Hz,2H,ArH),3.91(s,4H,NCH2Ar),3.75(s,4H,NCH2Ar),2.87(s,4H,NCH2CH2N),1.41(s,18H,C(CH3)3),1.23(s,18H,C(CH3)3). 13 C NMR (101MHz, CDCl3): δ158.33,154.02,147.58,140.50,136.65,135.67,129.64,129.08,127.58,127.29,1 26.41,124.44,123.19,121.72,121.05,60.04,59.10,50.66,35.04,34.21,31.84,29.79.Anal.Calcd.for C 52 H 66 N4O2: C, 80.16; H, 8.54; N, 7.19. Found: C, 79.81; H, 8.36; N, 6.94%.

[0066] Example 5

[0067] Synthesis of ligand L5

[0068] (1) Synthesis of N,N'-di[(N-methylbenzimidazol-2-yl)-methyl]ethylenediamine

[0069]

[0070] Except for the use of ethylenediamine (10 mmol, 0.60 g), N-methylbenzimidazole-2-carboxaldehyde (20.0 mmol, 3.20 g), and sodium borohydride (31.0 mmol, 1.18 g) as raw materials, the other operating steps were the same as in Example 1. A red oily substance (3.76 g, yield approximately 100%) was obtained.

[0071] (2) Synthesis of ligand L5

[0072]

[0073] Except for the use of N,N'-di[(N-methylbenzimidazol-2-yl)-methyl]ethylenediamine (approximately 10 mmol, 3.76 g), triethylamine (60 mmol, 6.07 g), and 2-bromomethyl-4,6-di-tert-butylphenol (20.0 mmol, 5.98 g) as raw materials, the other operations were the same as in Example 1, yielding a pale yellow solid (6.17 g, 78.3%). 1 H NMR(400MHz, CDCl3)δ10.70(br s,2H,OH),7.82(d, 3 J = 8.1 Hz, 2H, ArH), 7.53 (t, 3 J = 7.1 Hz, 2H, ArH), 7.36 (t, 3 J = 7.5 Hz, 2H, ArH), 7.25 (d, 3 J = 8.4 Hz, 2H, ArH), 7.22 (d, 4 J = 2.3 Hz, 2H, ArH), 6.87 (d, 4 J=2.2Hz,2H,ArH),3.81(s,4H,NCH2Ar),3.69(s,4H,NCH2Ar),2.76(s,4H,NCH2CH2N),1.77(s,6H,CH3),1.41(s,18H,C(CH3)3),1.23(s,18H,C(CH3)3). 13 C NMR (101MHz, CDCl3): δ158.33,154.02,140.50,136.65,129.64,129.08,127.58,127.29,126.41,1 24.44,123.19,121.72,121.05,60.04,59.10,50.66,35.04,34.21,31.84,29.79.Anal.Calcd.for C 50 H 68N6O2: C, 76.49; H, 8.73; N, 10.70. Found: C, 76.61; H, 8.48; N, 10.83%.

[0074] Example 6

[0075] Synthesis of ligand L6

[0076] (1)N 1 N 1 '-(ethane-1,2-diyl)bis(N 2 N 2 Synthesis of 1,2-dimethylethane-1,2-amine

[0077]

[0078] Diethyl oxalate (60 mmol, 5.30 g), anhydrous ethanol (50 mL), and N,N-dimethylethylenediamine (30 mmol, 4.40 g) were added to a 100 mL round-bottom flask. The mixture was stirred and heated under reflux for 2 hours. The resulting mixture was cooled to 0 °C, and the solid was separated by filtration. The solid was washed with diethyl ether and dried to give intermediate N. 1 N 1 '-(ethylenediamide-1,2-diyl)bis(N 2 N 2 (-Dimethylethane-1,2-amine)(4.14 g, 95%).

[0079] Under an argon atmosphere, the aforementioned substituted amide (15 mmol, 3.46 g) and dry tetrahydrofuran (50 mL) were added to a 100 °C three-necked flask. LiAlH4 (90 mmol, 3.42 g) was then added at 0 °C. The resulting suspension was heated under reflux for 2 h. Dichloromethane (5 mL) was added, followed by dropwise addition of a saturated aqueous solution of Na2SO4 until gas precipitation ceased and a white salt appeared. The solid was removed by filtration, and the filter cake was washed with a mixture of dichloromethane and methanol (9:1). The filtrate was dried over MgSO4, filtered, and evaporated under reduced pressure to give pure product N. 1 N 1 '-(ethane-1,2-diyl)bis(N 2 N 2 (-Dimethylethane-1,2-amine)(2.56 g, 84.3%).

[0080] (2) Synthesis of ligand L6

[0081]

[0082] To the N 1 N 1'-(ethane-1,2-diyl)bis(N 2 N 2 In a 50 mL round-bottom flask, 20 mL of dichloromethane, 60 mmol (6.07 g) of triethylamine (approximately 10 mmol, 2.02 g) and 2-bromomethyl-4-tert-butyl-6-phenylphenol (20 mmol, 6.38 g) were added to dimethylethane-1,2-amine (approximately 10 mmol, 2.02 g). The reaction was carried out at room temperature for 12 h. The reaction was quenched with water, extracted with dichloromethane, dried over anhydrous Na₂SO₄, and the solvent was removed under reduced pressure. The pH was adjusted to <2 with hydrochloric acid solution, and then extracted with dichloromethane. The aqueous phase was adjusted to >12 with sodium hydroxide solution, extracted with dichloromethane, dried over anhydrous Na₂SO₄, and the solvent was removed under reduced pressure. The resulting powder was dried under vacuum to obtain a yellow bubbly powder (4.77 g, 70.23%). 1 HNMR(400MHz, CDCl3)δ7.61–7.56(m,4H,ArH),7.41(t, 3 J=7.7Hz,4H,ArH),7.34–7.28(m,2H,ArH),7.24(d, 4 J = 2.5 Hz, 2H, ArH), 6.95 (d, 4 J=2.5Hz,2H,ArH),3.76(s,4H,NCH2Ar),2.73(s,4H,NCH2CH2N),2.58(t, 3 J = 7.8, 4H, NCH2CH2N), 2.38(t, 3 J=7.8,4H,NCH2CH2N),2.11(s,12H,N(CH3)2),1.29(s,18H,C(CH3)3). 13 C{ 1 H}NMR (101MHz, CDCl3, 298K): δ152.44,141.67,139.37,129.52,128.29,128.06,127.12,1 26.64,125.26,121.87,58.75,56.76,51.69,51.44,45.58,34.09,31.71.Anal.Calcd.for C 44 H 62 N4O2:C,77.83;H,9.20;N,8.25.Found:C,77.74;H,9.38;N,8.31.

[0083] Example 7

[0084] Synthesis of alkali metal complex Na1

[0085]

[0086] Under argon protection, ligand L1 (0.500 mmol, 340 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.500 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Tetra-n-butylammonium chloride (0.500 mmol, 139 mg) was then added, and the reaction was carried out at room temperature for another 12 h. Excess sodium hydride, sodium chloride, and trace impurities were removed by filtration. The filtrate was dried under reduced pressure to obtain a yellow, foamy solid. Recrystallization from tetrahydrofuran and n-hexane yielded a pale yellow solid (316 mg, 67.2%).

[0087] 1 H NMR(400MHz,C6D6)δ8.32(s,2H,ArH),7.44(s,2H,ArH),6.86(t, 3 J = 7.3 Hz, 2H, ArH), 6.73 (d, 4 J = 6.9 Hz, 2H, ArH), 6.38 (d, 3 J=60Hz,2H,ArH),3.98(br s,4H,NCH2Ar),3.52(s,4H,NCH2Ar),3.06(s,4H,NCH2CH2N),2.78(s,8H,N(CH2CH2CH2CH3)4 ),1.91(s,18H,C(CH3)3),1.52(s,18H,C(CH3)3),1.10(m,16H,N(CH2CH2CH2CH3)4),0.76(t, 3 J=6.5Hz,8H,N(CH2CH2CH2CH3)4).Anal.Calcd.for C 60 H 96 N5O2Na·0.5C4H8O: C, 76.47; H, 10.27; N, 7.43. Found: C, 76.03; H, 10.29; N, 7.52%.

[0088] Example 8

[0089] Synthesis of alkali metal complex Na2

[0090]

[0091] Under argon protection, ligand L2 (0.500 mmol, 318 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.500 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Tetra-n-butylammonium chloride (0.500 mmol, 139 mg) was then added, and the reaction was carried out at room temperature for another 12 h. Excess sodium hydride, sodium chloride, and trace impurities were removed by filtration. The filtrate was dried under vacuum to obtain a yellow, foamy solid. Recrystallization from tetrahydrofuran and n-hexane yielded a white solid (228 mg, 50.80%).

[0092] 1 H NMR (400MHz, C6D6) δ8.36(s,2H,ArH),7.37(d,J=3.0Hz,2H,ArH),7.12(d,J=3.1Hz,2H,ArH),6.96( t,J=6.3Hz,2H,ArH),6.86(s,2H,ArH),6.47(t,J=6.3Hz,2H,ArH),3.60-3.53(m,2H,THF),3.41(br s,4H,NCH2Ar),2.78(s,4H,NCH2Ar),2.44(t, 3 J=8.3Hz,8H,N(CH2CH2CH2CH3)4),1.78(s,18H,C(CH3)3),1.46-1.33(m,2H,THF)1.13-1.01(m,8H,N(CH2CH2C H2CH3)4),1.02–0.94(m,8H,N(CH2CH2CH2CH3)4),0.80(t,J=7.2Hz,12H,N(CH2CH2CH2CH3)4).Anal.Calcd.for C 54 H 78 N5O2Cl2Na·0.5C4H8O: C, 69.46; H, 8.74; N, 7.79. Found: C, 69.17; H, 8.72; N, 7.52%.

[0093] Example 9

[0094] Synthesis of alkali metal complex Na3

[0095]

[0096] Under argon protection, ligand L3 (0.500 mmol, 359 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.500 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Tetra-n-butylammonium chloride (0.500 mmol, 139 mg) was then added, and the reaction was carried out at room temperature for another 12 h. Excess sodium hydride, sodium chloride, and trace impurities were removed by filtration. The filtrate was dried under vacuum to obtain a yellow, foamy solid. Recrystallization from tetrahydrofuran and n-hexane yielded a pale yellow solid (297 mg, 60.55%).

[0097] 1 H NMR (400MHz, C6D6, 298K): δ8.57(s,2H,ArH),8.24(d, 3 J = 7.6 Hz, 4H, ArH), 7.51 (d, 3 J = 2.9 Hz, 2H, ArH), 7.34 (t, 3 J = 7.5 Hz, 4H, ArH), 7.21 (d, 3 J = 2.9 Hz, 2H, ArH), 7.09 (t, 3 J=7.3Hz,2H,ArH),6.99–6.83(m,4H,ArH),6.45(s,2H,ArH),3.86–3.57(m,4H,NCH2Ar),3.46–3.60(m,10.8H,THF),2.88(s,4H,NCH2CH2N),2.52(t, 3 J=8.3Hz,8H,N(CH2CH2CH2CH3)4),1.25–1.16(m,2H,Hex)1.49(s,18H,C(CH3)3),1.46–1.35(m,10.8H ,THF),0.98–0.89(m,9.5H,N(CH2CH2CH2CH3)4,Hex),0.89–0.77(m,8H,N(CH2CH2CH2CH3)4),0.69(t, 3 J=7.1Hz,12H,N(CH2CH2CH2CH3)4).Anal.Calcd.for C 64 H 88 N5O2Na·2.7C4H8O·0.19C6H 14 :C,76.42;H,9.48;N,5.87.Found:C,76.90;H,9.18;N,6.37%.

[0098] Example 10

[0099] Synthesis of alkali metal complex Na4

[0100]

[0101] Under argon protection, ligand L4 (0.500 mmol, 390 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.500 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Tetra-n-butylammonium chloride (0.500 mmol, 139 mg) was then added, and the reaction was carried out at room temperature for another 12 h. Excess sodium hydride, sodium chloride, and trace impurities were removed by filtration. The filtrate was dried under vacuum to obtain a yellow, foamy solid. Recrystallization from tetrahydrofuran and n-hexane yielded a pale yellow solid (342 mg, 65.66%).

[0102] 1 H NMR (400MHz, C6D6, 298K): δ8.45(d, 3 J = 8.5 Hz, 2H, ArH), 7.42 (ddd, 3 J=8.4,6.4,1.8Hz,2H,ArH),7.35(d, 4 J=2.8Hz,2H,ArH),7.22–7.17(m,2H,ArH),7.11(d, 4 J=2.8Hz,2H,ArH),7.09–6.98(m,4H,ArH),6.94(d, 3 J=9.2Hz,2H,ArH),3.82–3.60(m,6H,NCH2Ar),3.60-3.48(m,6.4H,THF),3.10(s,4H,NCH2Ar),2.69(t, 3 J=8.1Hz,8H,N(CH2CH2CH2CH3)4),1.77(s,18H,C(CH3)3),1.50(s,18H,C(CH3)3),1.43–1.38(m,6.4H,T HF),1.29–1.21(m,2H,Hex),1.11–1.00(m,18H,N(CH2CH2CH2CH3)4),0.94–0.80(m,1.5H,Hex),0.73(t, 3 J=6.9Hz,12H,N(CH2CH2CH2CH3)4). 13C NMR (101MHz, C6D6) δ169.60,161.57,148.51,136.15,135.41,129.01,127.33,127.19,126.70,125.61,123.84,123.07,122.37(All Ar-C),67.82(THF),57.84(pyridyl-CH2),35.81(N-CH2-Ar),33.95(NCH2CH2N),32.86(Hex) ,30.44(C(CH3)3),25.82(THF),23.87(Hex),19.75(C(CH3)3),13.89(Hex).Anal.Calcd.for C 64 H 88 N5O2Na·1.6C4H8O·0.25C6H 14 :C,76.42;H,9.48;N,5.87.Found:C,76.72;H,9.97;N,6.25%.

[0103] Example 11

[0104] Synthesis of alkali metal complex Na5

[0105]

[0106] Under argon protection, ligand L5 (0.500 mmol, 394 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.500 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Next, tetrabutylammonium chloride (0.500 mmol, 139 mg) was added, and the reaction was carried out at room temperature for another 12 h. Excess sodium hydride, sodium chloride, and trace impurities were removed by filtration. The filtrate was dried under vacuum to obtain a yellow, foamy solid. Recrystallization from tetrahydrofuran and n-hexane yielded a pale yellow solid (333 mg, 63.55%).

[0107] 1 H NMR (400MHz, C6D6, 298K): δ7.42 (dd, 3 J=8.4,6.4Hz,2H,ArH),7.35–7.22(m,4H,ArH),7.09–6.98(m,4H,ArH),6.94(d, 3 J=9.2Hz,2H,ArH),3.85–3.62(m,6H,NCH2Ar),3.60-3.48(m,2H,THF),3.10(s,4H,NCH2Ar),2.69(t, 3J=8.1Hz,8H,N(CH2CH2CH2CH3)4),1.77(s,18H,C(CH3)3),1.64(s,6H,CH3)1.50(s,18 H,C(CH3)3),1.43–1.38(m,2H,THF),1.11–1.00(m,18H,N(CH2CH2CH2CH3)4),0.73(t, 3 J=6.9Hz,12H,N(CH2CH2CH2CH3)4). 13 C NMR (101MHz, C6D6) δ161.57,148.51,136.15,129.01,127.33,127.19,126.70,125.61,123.84,123.07,122.37(All Ar-C),67.82(THF),57.84(benzimidazolyl-CH2),35.81(N-CH2-Ar),33.95(NCH2CH2N),30.44(C(CH3)3),25.82(THF),19.75(C(CH3)3).Anal.Calcd.forC 66 H 102 N7O2Na·0.5C4H8O: C, 75.30; H, 9.85; N, 9.40. Found: C, 75.75; H, 9.63; N, 9.07%.

[0108] Example 12

[0109] Synthesis of alkali metal complex Na6

[0110]

[0111] Under argon protection, ligand L6 (0.500 mmol, 339 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.500 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Next, tetrabutylammonium chloride (0.500 mmol, 139 mg) was added, and the reaction was carried out at room temperature for another 12 h. Excess sodium hydride, sodium chloride, and trace impurities were removed by filtration. The filtrate was dried under vacuum to obtain a yellow, foamy solid. Recrystallization from tetrahydrofuran and n-hexane yielded a pale yellow solid (300 mg, 63.72%).

[0112] 1H NMR (400MHz, C6D6): δ8.23(d,J=7.6Hz,2H,ArH),7.57(d,J=2.9Hz,2H,ArH),7.32(t,J=7.6Hz,4H,ArH),7.25(d,J=2 .9Hz,2H,ArH)),7.09(t,J=7.4Hz,2H,ArH),3.61–3.49(m,10H,THF),2.72(s,4H,NCH2Ar),2.55(t,J=8.4Hz,8H,N(C H2CH2CH2CH3)4),2.21(s,4H,NCH2CH2N(CH3)2),2.05(s,12H,N(CH3)2),1.51(s,18H,C(CH3)3),1.46–1.35(m,10H, THF),0.91(m,8H,N(CH2CH2CH2CH3)4),0.78(m,8H,N(CH2CH2CH2CH3)4),0.72(t,J=7.2Hz,12H,N(CH2CH2CH2CH3)4). 13 C NMR(101MHz,C6D6)δCalcd.for C 54 H 78 N5O2Cl2Na·2C4H8O: C, 74.16; H, 10.39; N, 6.44. Found: C, 74.66; H, 10.05; N, 6.80%.

[0113] Example 13

[0114] Synthesis of alkali metal complex Na7

[0115]

[0116] Under argon protection, ligand L1 (0.500 mmol, 340 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.500 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Tetramethylammonium bromide (0.500 mmol, 77.0 mg) was then added, and the reaction was carried out at room temperature for another 12 h. Excess sodium hydride, sodium chloride, and trace impurities were removed by filtration. The filtrate was dried under reduced pressure to obtain a yellow, foamy solid. Recrystallization from tetrahydrofuran and n-hexane yielded a pale yellow solid (206 mg, 53.3%).

[0117] 1 H NMR(400MHz,C6D6)δ8.34(s,2H,ArH),7.47(s,2H,ArH),6.83(t, 3 J = 7.3 Hz, 2H, ArH), 6.78 (d,4 J = 6.9 Hz, 2H, ArH), 6.43 (d, 3 J=60Hz,2H,ArH),3.90(br s,4H,NCH2Ar),3.54(s,4H,NCH2Ar),3.12(s,4H,NCH2CH2N),2.58(s,12H,N(CH3)4),1.93(s,18H,C(CH3)3),1.54(s,18H,C(CH3)3). 13 C NMR (101MHz, C6D6) δ168.60,163.67,147.41,129.01,127.33,127.21,126.14,125.61,123.77,123.07,122.37(All Ar-C),57.84(pyridyl-CH2),35.81(N-CH2-Ar),33.95(NCH2CH2N),30.44(C(CH3)3),19.75(C(CH3)3).Anal.Calcd.forC 64 H 88 N5O2Na: C, 74.47; H, 9.38; N, 9.05. Found: C, 74.83; H, 9.04; N, 9.22%.

[0118] Example 14

[0119] Synthesis of alkali metal complex K1

[0120]

[0121] Under argon protection, ligand L1 (0.500 mmol, 340 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. KH (1.500 mmol, 60 mg) was then slowly added, and the reaction was carried out at room temperature for 12 h. Tetra-n-butylammonium chloride (0.500 mmol, 139 mg) was then added, and the reaction was carried out at room temperature for another 12 h. Excess potassium hydride, potassium chloride, and trace impurities were removed by filtration. The filtrate was dried under vacuum to obtain a yellow, foamy solid. Recrystallization from tetrahydrofuran and n-hexane yielded a pale yellow solid (321 mg, 33.6%).

[0122] 1 H NMR(400MHz,THF)δ8.29(s,2H,ArH),7.32(t, 3J=1.6Hz,2H,ArH),7.00-6.80(m,6H,ArH),6.72(s,2H,ArH),3.55(br s,4H,NCH2Ar),3.43–3.28(m,12H,NCH2Ar and N(CH2CH2CH2CH3)4),2.66(br s,4H,NCH2CH2N),1.58(m,8H,N(CH2CH2CH2CH3)4),1.42(s,18H,C(CH3)3),1.34(m,8H,N(CH2CH2CH2CH3)4),1.18(s,18H,C(CH3)3),0.86(t, 3 J=7.3Hz,12H,N(CH2CH2CH2CH3)4). 13 C NMR(101MHz,THF)δ169.80,161.86,149.76,149.61,136.29,136.20,135.81,124.42,121.85,121.60(All Ar-C),36.17,34.29,33.10,32.91,30.72,30.52,20.72,14.30(C(CH3)3),14.16(C(CH3)3).Anal.Calcd.for C 60 H 96 NO2K: C, 75.10; H, 10.04; N, 7.22. Found: C, 75.18; H, 10.09; N, 7.31%.

[0123] Example 15

[0124] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to a polymerization flask and dissolved in 0.4 mL of toluene, followed by 0.1 mL of benzyl alcohol in toluene solution. 0.5 mL of catalyst Na1 in toluene solution was added to the polymerization flask. [rac-LA]0 = 1.0 M, [Na]0 = 0.002 M, [BnOH]0 = 0.002 M, [rac-LA]0:[Na]0:[BnOH]0 = 500:1:1. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was carried out for 900 seconds. Petroleum ether was added to terminate the reaction. The solvent was removed, and the residue was dissolved in dichloromethane. Methanol was added to precipitate the polymer. The mixture was vacuum dried for 24 h. The conversion rate was 88%, M n =4.40×10 4 g / mol, molecular weight distribution PDI = 1.64, isotacticity P m =0.54.

[0125] Example 16

[0126] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to a polymerization flask and dissolved in 0.3 mL of toluene, followed by 0.2 mL of benzyl alcohol in toluene solution. 0.5 mL of catalyst Na1 in toluene solution was added to the polymerization flask. [rac-LA]0 = 1.0 M, [Na]0 = 0.002 M, [BnOH]0 = 0.004 M, [rac-LA]0:[Na]0:[BnOH]0 = 500:1:2. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was carried out for 95 seconds. Petroleum ether was added to terminate the reaction. The solvent was removed, and the residue was dissolved in dichloromethane. Methanol was added to precipitate the polymer. The mixture was vacuum dried for 24 h. The conversion rate was 90%, M n =4.05×10 4 g / mol, molecular weight distribution PDI = 1.72, isotacticity P m =0.60.

[0127] Example 17

[0128] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to a polymerization flask and dissolved in 0.2 mL of toluene, followed by 0.3 mL of benzyl alcohol in toluene solution. 0.5 mL of catalyst Na1 in toluene solution was added to the polymerization flask. [rac-LA]0 = 1.0 M, [Na]0 = 0.002 M, [BnOH]0 = 0.006 M, [rac-LA]0:[Na]0:[BnOH]0 = 500:1:3. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was carried out for 97 seconds. Petroleum ether was added to terminate the reaction. The solvent was removed, and the residue was dissolved in dichloromethane. Methanol was added to precipitate the polymer. The mixture was then vacuum dried for 24 h. The conversion rate was 92%, M n =3.03×10 4 g / mol, molecular weight distribution PDI = 1.68, isotacticity P m =0.62.

[0129] Example 18

[0130] Except for the temperature being changed to -50±1℃, the other operations were the same as in Example 16. After 620 seconds of reaction, the conversion rate was 66%, M n =3.10×10 4 g / mol, molecular weight distribution PDI = 1.70, isotacticity P m =0.87.

[0131] Example 19

[0132] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to a polymerization flask and dissolved in 0.3 mL of tetrahydrofuran, followed by 0.2 mL of benzyl alcohol in tetrahydrofuran solution. 0.5 mL of catalyst Na1 in tetrahydrofuran solution was added to the polymerization flask. [rac-LA]0 = 1.0 M, [Na]0 = 0.002 M, [BnOH]0 = 0.004 M, [rac-LA]0:[Na]0:[BnOH]0 = 500:1:2. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was carried out for 600 seconds. Petroleum ether was added to terminate the reaction. The solvent was removed, and the residue was dissolved in dichloromethane. Methanol was added to precipitate the polymer. The mixture was vacuum dried for 24 h. The conversion rate was 85%, M n =3.12×10 4 g / mol, molecular weight distribution PDI = 1.68, isotacticity P m =0.76.

[0133] Example 20

[0134] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to a polymerization flask and dissolved in 0.3 mL of toluene, followed by 0.2 mL of benzyl alcohol in toluene solution. 0.5 mL of catalyst Na1 in toluene solution was added to the polymerization flask. [rac-LA]0 = 1.0 M, [Na]0 = 0.0004 M, [BnOH]0 = 0.0008 M, [rac-LA]0:[Na]0:[BnOH]0 = 2500:1:2. The reaction was carried out at -50 ± 1 °C for 38 minutes, then petroleum ether was added to terminate the reaction. The solvent was removed, and the residue was dissolved in dichloromethane. Methanol was added to precipitate the polymer. The mixture was then vacuum dried for 24 h. The conversion rate was 63%. n =1.34×10 5 g / mol, molecular weight distribution PDI = 1.18, isotacticity P m =0.89.

[0135] Example 21

[0136] Except for the temperature being changed to -70±1℃, the other operations were the same as in Example 16. After 92 minutes of reaction, the conversion rate was 75%, M n =2.78×10 4 g / mol, molecular weight distribution PDI = 1.04, isotacticity P m =0.93.

[0137] Example 22

[0138] Except for replacing the catalyst with Na2, the other operations were the same as in Example 16. After reacting for 340 seconds, the conversion rate was 88%, M n =2.52×10 4g / mol, molecular weight distribution PDI = 1.30, isotacticity P m =0.57.

[0139] Example 23

[0140] Except for replacing the catalyst with Na2, the other operations were the same as in Example 17. After reacting for 250 seconds, the conversion rate was 90%, M n =2.21×10 4 g / mol, molecular weight distribution PDI = 1.29, isotacticity P m =0.58.

[0141] Example 24

[0142] Except for replacing the catalyst with Na2 and changing the temperature to -50±1℃, the other operations were the same as in Example 16. After 4 hours of reaction, the conversion rate was 68%, M n =2.52×10 4 g / mol, molecular weight distribution PDI = 1.13, isotacticity P m =0.86.

[0143] Example 25

[0144] Except for replacing the catalyst with Na2 and changing the temperature to -50±1℃, the other operations were the same as in Example 17. After reacting for 150 minutes, the conversion rate was 65%, M n =1.59×10 4 g / mol, molecular weight distribution PDI = 1.10, isotacticity P m =0.86.

[0145] Example 26

[0146] Except for replacing the catalyst with Na3, the other operations were the same as in Example 16. After 540 seconds of reaction, the conversion rate was 97%, M n =3.34×10 4 g / mol, molecular weight distribution PDI = 1.32, isotacticity P m =0.63.

[0147] Example 27

[0148] Except for replacing the catalyst with Na3, the other operations were the same as in Example 17. After 3 minutes of reaction, the conversion rate was 91%, M n =2.76×10 4 g / mol, molecular weight distribution PDI = 1.23, isotacticity P m =0.53.

[0149] Example 28

[0150] Except for replacing the catalyst with Na3 and changing the temperature to -50±1℃, the other operations were the same as in Example 16. After reacting for 100 minutes, the conversion rate was 93%, M n =3.51×10 4 g / mol, molecular weight distribution PDI = 1.21, isotacticity P m =0.86.

[0151] Example 29

[0152] Except for replacing the catalyst with Na3 and changing the temperature to -50±1℃, the other operations were the same as in Example 17. After reacting for 52 minutes, the conversion rate was 95%, M n =2.58×10 4 g / mol, molecular weight distribution PDI = 1.19, isotacticity P m =0.84.

[0153] Example 30

[0154] Except for replacing the catalyst with Na4, the other operations were the same as in Example 16. After reacting for 140 seconds, the conversion rate was 95%, M n =3.53×10 4 g / mol, molecular weight distribution PDI = 1.88, isotacticity P m =0.62.

[0155] Example 31

[0156] Except for replacing the catalyst with Na4, the other operations were the same as in Example 17. After 90 seconds of reaction, the conversion rate was 95%, M n =2.57×10 4 g / mol, molecular weight distribution PDI = 1.69, isotacticity P m =0.65.

[0157] Example 32

[0158] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to a polymerization flask and dissolved in 0.3 mL of toluene, followed by 0.2 mL of benzyl alcohol in toluene solution. 0.5 mL of Na₄ catalyst in toluene solution was added to the polymerization flask. [rac-LA]₀ = 1.0 M, [Na]₀ = 0.002 M, [BnOH]₀ = 0.01 M, [rac-LA]₀:[Na]₀:[BnOH]₀ = 500:1:5. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was stopped after 50 seconds by adding petroleum ether. The solvent was removed, and the residue was dissolved in dichloromethane. Methanol was added to precipitate the polymer. The mixture was then vacuum dried for 24 h. The conversion rate was 90%, M n =1.34×10 4 g / mol, molecular weight distribution PDI = 1.58, isotacticity Pm =0.62.

[0159] Example 33

[0160] Except for [BnOH]0 = 0.02M and [rac-LA]0:[Na]0:[BnOH]0 = 500:1:10, the other operations were the same as in Example 32. After reacting for 10 seconds, the conversion rate was 92%. n =7.2×10 3 g / mol, molecular weight distribution PDI = 1.23, isotacticity P m =0.61.

[0161] Example 34

[0162] Except for replacing the catalyst with Na4 and changing the temperature to -50±1℃, the other operations were the same as in Example 16. After reacting for 48 minutes, the conversion rate was 85%, M n =4.10×10 4 g / mol, molecular weight distribution PDI = 1.85, isotacticity P m =0.85.

[0163] Example 35

[0164] Except for replacing the catalyst with Na4 and changing the temperature to -50±1℃, the other operations were the same as in Example 17. After reacting for 30 minutes, the conversion rate was 89%, M n =2.70×10 4 g / mol, molecular weight distribution PDI = 1.68, isotacticity P m =0.82.

[0165] Example 36

[0166] Except for replacing the catalyst with Na5, the other operations were the same as in Example 16. After 240 seconds of reaction, the conversion rate was 90%, M n =3.24×10 4 g / mol, molecular weight distribution PDI = 1.52, isotacticity P m =0.60.

[0167] Example 37

[0168] Except for replacing the catalyst with Na5, the other operations were the same as in Example 17. After 100 seconds of reaction, the conversion rate was 91%, M n =2.66×10 4 g / mol, molecular weight distribution PDI = 1.53, isotacticity P m =0.53.

[0169] Example 38

[0170] Except for replacing the catalyst with Na5 and changing the temperature to -50±1℃, the other operations were the same as in Example 16. After reacting for 108 minutes, the conversion rate was 93%, M n =3.61×10 4 g / mol, molecular weight distribution PDI = 1.29, isotacticity P m =0.82.

[0171] Example 39

[0172] Except for replacing the catalyst with Na5 and changing the temperature to -50±1℃, the other operations were the same as in Example 17. After reacting for 70 minutes, the conversion rate was 95%, M n =2.50×10 4 g / mol, molecular weight distribution PDI = 1.29, isotacticity P m =0.83.

[0173] Example 40

[0174] Except for replacing the catalyst with Na6 and benzyl alcohol with isopropanol, the other operations were the same as in Example 16. After reacting for 330 seconds, the conversion rate was 92%, M n =3.21×10 4 g / mol, molecular weight distribution PDI = 1.45, isotacticity P m =0.57.

[0175] Example 41

[0176] Except for replacing the catalyst with Na6, the other operations were the same as in Example 17. After reacting for 130 seconds, the conversion rate was 92%, M n =2.81×10 4 g / mol, molecular weight distribution PDI = 1.32, isotacticity P m =0.56.

[0177] Example 42

[0178] Except for replacing the catalyst with Na6 and changing the temperature to -50±1℃, the other operations were the same as in Example 17. After 96 minutes of reaction, the conversion rate was 88%, M n =2.41×10 4 g / mol, molecular weight distribution PDI = 1.09, isotacticity P m =0.86.

[0179] Example 43

[0180] Except for replacing the catalyst with Na7, the other operations were the same as in Example 16. After reacting for 230 seconds, the conversion rate was 90%, M n =3.11×10 4 g / mol, molecular weight distribution PDI = 1.55, isotacticity Pm =0.55.

[0181] Example 44

[0182] Except for replacing the catalyst with Na7, the other operations were the same as in Example 17. After reacting for 100 seconds, the conversion rate was 92%, M n =2.85×10 4 g / mol, molecular weight distribution PDI = 1.35, isotacticity P m =0.58.

[0183] Example 45

[0184] Except for replacing the catalyst with Na7 and changing the temperature to -50±1℃, the other operations were the same as in Example 17. After reacting for 45 minutes, the conversion rate was 88%, M n =2.52×10 4 g / mol, molecular weight distribution PDI = 1.21, isotacticity P m =0.83.

[0185] Example 46

[0186] Except for replacing the catalyst with K1, the other operations were the same as in Example 16. After reacting for 220 seconds, the conversion rate was 87%, M n =3.83×10 4 g / mol, molecular weight distribution PDI = 1.67, isotacticity P m =0.58.

[0187] Example 47

[0188] Except for replacing the catalyst with K1, the other operations were the same as in Example 17. After reacting for 149 seconds, the conversion rate was 94%, M n =2.60×10 4 g / mol, molecular weight distribution PDI = 1.52, isotacticity P m =0.56.

[0189] Example 48

[0190] Except for replacing the catalyst with K1, and setting the monomers [K]0 = 0.002M, [BnOH]0 = 0.01M, and [rac-LA]0:[K]0:[BnOH]0 = 500:1:5, the other operations were the same as in Example 15. After reacting for 130 seconds, the conversion rate was 92%. n =2.15×10 4 g / mol, molecular weight distribution PDI = 1.50, isotacticity P m =0.53.

[0191] Example 49

[0192] Except for replacing the monomer with L-lactide, the other operations were the same as in Example 34. After reacting for 31 minutes, the conversion rate was 90%, M n =3.65×10 4 g / mol, molecular weight distribution PDI = 1.31, isotacticity P m =1.

[0193] Example 50

[0194] Under argon protection, racemic lactide (0.288 g, 1.0 mmol) was added to a polymerization flask, followed by 0.1 mL of a toluene solution of benzyl alcohol. 0.1 mL of a toluene solution of catalyst Na1 was added to the polymerization flask. The reaction ratio was [rac-LA]0:[Na]0:[BnOH]0 = 1000:1:2. The reaction temperature was controlled at 140 ± 1 °C, and the reaction was carried out for 120 seconds. Petroleum ether was added to terminate the reaction. The residue was dissolved in dichloromethane, and methanol was added to precipitate the polymer. The mixture was then vacuum dried for 24 h. The conversion rate was 88%, M... n =7.40×10 4 g / mol, molecular weight distribution PDI = 1.64, isotacticity P m =0.54.

[0195] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cationic-anionic para-aminobisphenol alkali metal complex (I), characterized in that, It has the following general formula: In formula (I): R 1 ~R 2 Representing C1 to C respectively 10 Straight-chain and branched alkyl groups, cumyl, triphenylmethyl, C6-C6 12 aryl, or halogen; R 3 Representing C1 to C 10 Alkyl groups with straight-chain or branched structures; A is a group having a structure as shown in formula (II), (III), (IV), (V) or (VI): A coordinates with the metal center M through its nitrogen atom; M represents Na and K.

2. The anionic and cation-type aminobisphenol alkali metal complex (I) according to claim 1, characterized in that, R 1 ~R 2 It is a C1-C6 straight-chain or branched alkyl group, cumyl group, triphenylmethyl group, C6-C8 aryl group, or halogen; R 3 It is an alkyl group with a C1-C6 straight-chain or branched structure; A is a group having a structure as shown in formula (II), (III), (V) or (VI):

3. The anionic and cationic para-aminobisphenol alkali metal complex (I) according to claim 1, characterized in that, R 1 ~R 2 Methyl, isopropyl, tert-butyl, cumyl, triphenylmethyl, phenyl, halogen; R 3 The derivatives are methyl, ethyl, isopropyl, and n-butyl.

4. A method for preparing the anionic and cation-type aminobisphenol alkali metal complex (I) according to any one of claims 1 to 3, comprising the following steps: Ethylenediamine is reacted with an aldehyde-substituted nitrogen-containing heterocyclic compound of formula (VIII) and reduced by a reducing agent to generate the corresponding di-secondary amine; then 2-bromomethyl-4,6-disubstituted phenol (IX) is added and reacted at a temperature of 0–90 °C for 2–72 hours, and the aminobisphenol ligand compound (VII) is collected from the reaction product; or diethyl oxalate is reductively amination reaction with a primary amine of formula (X) to generate the corresponding di-secondary amine, then 2-bromomethyl-4,6-disubstituted phenol (IX) is added and reacted at a temperature of 0–90 °C for 2–72 hours, and the aminobisphenol ligand compound (VII) is collected from the reaction product. Optionally, the aminobisphenol ligand compound shown in formula (VII) is reacted with a metal hydride in an organic medium, followed by the addition of a quaternary ammonium salt [NR]. 3 4]X continued to react at a temperature of 0–100 °C for 2–24 hours, and then the anionic and cation-type aminobisphenol alkali metal target complex (I) was collected from the reaction product; Substituent R in the reaction formula 1 ~R 2 A is consistent with the corresponding groups of the anionic and cation-type aminobisphenol alkali metal complex (I) according to any one of claims 1 to 3; The metal hydride MH is NaH or KH; The quaternary ammonium salt [NR] 3 In X, R 3 It is consistent with the corresponding groups of the anionic and cation-type aminobisphenol alkali metal complex (I) according to any one of claims 1 to 3; X is Cl, Br, I or OH.

5. The method according to claim 4, characterized in that, Aminobisphenol ligand compounds (VII) with metal hydrides and quaternary ammonium salts [NR] 3 4] The molar ratio of X is 1:2.0-3.0:0.8-1.5; the reducing agent is sodium borohydride or lithium aluminum hydride; the organic medium is selected from one or two of tetrahydrofuran, diethyl ether, toluene, benzene, petroleum ether and n-hexane.

6. The application of the anionic and cation-type aminobisphenol alkali metal complex according to any one of claims 1 to 3, characterized in that, Used for the ring-opening polymerization of lactones.

7. The application according to claim 6, characterized in that, The lactone is selected from L-lactide, D-lactide, rac-lactide, and meso-lactide.

8. The application according to claim 6, characterized in that, Using the anionic and p-type aminobisphenol alkali metal complexes according to any one of claims 1 to 3 as catalysts, lactide is polymerized, wherein the molar ratio of catalyst to monomer during polymerization is 1:1 to 10000.

9. The application according to claim 6, characterized in that, Using the anionic and cationic para-aminobisphenol alkali metal complexes according to any one of claims 1 to 3 as catalysts, lactide is polymerized at -70 to 180°C in the presence of an alcohol, wherein the molar ratio of catalyst to alcohol and lactide during polymerization is 1:1 to 50:1 to 10000; wherein the alcohol is C1 to C2. 10 Alkyl alcohols with straight-chain, branched, or cyclic structures, C7–C6 20 Mono- or polyaryl-substituted alkyl alcohols.

10. The application according to claim 6, characterized in that, Using the anionic and p-type aminobisphenol alkali metal complexes of any one of claims 1 to 3 as catalysts, lactide is polymerized at -70 to 140°C in the presence of an alcohol, wherein the molar ratio of catalyst to alcohol and lactide during polymerization is 1:1 to 20:20 to 5000; wherein the alcohol is isopropanol or benzyl alcohol.

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