An ethylene-bridged aminobisphenolate alkali metal complex, its preparation method and use

Abstract

The application discloses a kind of ethylene bridging aminobisphenol oxy alkali metal complex and its preparation method and application in high activity catalytic lactone ring-opening polymerization.The preparation method includes the following steps: neutral ethylene bridging aminobisphenol ligand is reacted with metal hydride in organic medium, then is filtered, concentrated, and the target compound is obtained through recrystallization step.The ethylene bridging aminobisphenol oxy alkali metal complex of the application is a kind of high-efficiency lactone ring-opening polymerization catalyst, and can be used for the polymerization reaction of high activity catalytic lactide etc.The ethylene bridging aminobisphenol oxy alkali metal complex of the application has very obvious advantages: raw material is easy to obtain, synthesis route is simple, has high catalytic activity, can obtain high molecular weight polyester material, meets the needs of industrial department.The structural formula is as shown below:

Description

Technical Field

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

[0002] Polylactide (PLA), as a novel environmentally friendly material, exhibits superior biocompatibility and biodegradability compared to traditional polyolefin materials, making it a highly valuable alternative to petroleum-based plastics such as polyethylene. Polylactide (also known as polylactic acid) is produced by the microbial fermentation of renewable resources such as corn, wheat, and sorghum to generate lactic acid, which is then polymerized through a specific process. Due to its excellent biocompatibility, complete biodegradability, low cytotoxicity, and good barrier and mechanical processing properties, it has become one of the most promising biodegradable polymer materials on the market.

[0003] Lactose (LA) is a dimer of lactic acid, containing two chiral centers and existing in three isomers: L-LA, D-LA, and meso-LA. Mixing L-LA and D-LA in equimolar amounts yields rac-LA. Catalyzing the polymerization of lactose with different configurations can produce polylactide with various microstructures. The applications of polylactide with different microstructures vary due to their different physical properties. Currently, the industrial production of polylactide mainly relies on stannous octoate catalysts. Stannous octoate exhibits moderate catalytic activity for lactose polymerization, but due to the toxicity of metallic tin, its residues in the polymer negatively impact its use in the biopharmaceutical field. Therefore, developing highly active catalysts with biocompatible metals is of great significance for the industrial production of lactose. Alkali metals are biocompatible, and even if they remain in the polymer, the harm is minimal. Therefore, alkali metal-based catalysts have attracted much attention; however, reports on highly active alkali metal complexes for catalyzing lactose polymerization are still limited.

[0004] In 2011, the Mountford group synthesized a [OOO]-type tridentate bisphenol O potassium complex, which exhibited high activity and controllability for the ring-opening polymerization of rac-LA. Under conditions of room temperature, dichloromethane, and the addition of 1 equivalent of benzyl alcohol, the monomer was completely converted within 5 minutes of catalyzing the polymerization of 300 equivalents of rac-LA (Inorg. Chem., 2011, 50, 3589–3595). In 2015, the Francesca group synthesized a tetranuclear alkali metal complex. Under conditions of room temperature, tetrahydrofuran, and the addition of 1 equivalent of benzyl alcohol, the monomer was completely converted within 3 minutes of catalyzing the polymerization of 250 equivalents of rac-LA, demonstrating good polymerization controllability (Dalton Trans., 2015, 44, 20216-20231). In 2015, Cano's group synthesized iminophenoxy alkali metal complexes. The potassium complex exhibited high catalytic activity for the ring-opening polymerization of rac-LA. At room temperature, with the addition of 1 equivalent of benzyl alcohol as an initiator, the monomer conversion of 100 equivalents of rac-LA reached 99% in 30 seconds. Under the same conditions, the lithium complex showed lower activity, requiring 45 minutes to completely convert 100 equivalents of monomer (Organometallics, 2015, 34, 477–487). In 2014, Wu's group synthesized sodium and potassium complexes containing crown ether structures of purine monophenoloxy groups. These complexes exhibited high catalytic activity for the polymerization of racemic lactide. At room temperature, with the addition of 10 equivalents of benzyl alcohol, the polymerization of 500 equivalents of rac-LA was completely converted in only 2 minutes (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 substituted with triphenylmethyl groups. This complex exhibited very high catalytic activity for rac-LA polymerization. In toluene at room temperature, the addition of 10 equivalents of benzyl alcohol catalyzed the complete polymerization of 1000 equivalents of rac-LA in just 1 minute, with good polymerization controllability (Catal. Sci. Technol., 2016, 6, 515–520). In 2017, Wang's group synthesized an iminophenoxy crown ether potassium complex. This type of complex exhibits high catalytic activity at room temperature. In toluene at room temperature, the addition of 1 equivalent of benzyl alcohol catalyzed the complete polymerization of 100 equivalents of rac-LA in just 1 minute; even at 0°C, the monomer was completely converted in only 20 minutes. The presence of sterically hindered substituents on the ligands is beneficial for improving the activity of the corresponding complexes (RSC Adv., 2017, 7, 24055–24063).In 2017, Ma's group reported that the aminophenoxy potassium complex could be completely converted by adding 1 equivalent of isopropanol to toluene at room temperature and catalyzing the polymerization of 500 equivalents of rac-LA for 3 minutes. The molecular weight of the obtained polymer was close to the theoretical molecular weight (Dalton Trans., 2017, 46, 6087–6097).

[0005] As shown above, the number of alkali metal complexes with high catalytic activity for the ring-opening polymerization of racemic lactide remains limited, and they often require the addition of a large proportion of alcohol, resulting in low molecular weight polymers. Furthermore, these complexes have low tolerance to impurities and cannot catalyze the polymerization of large proportions of monomers. Therefore, developing highly active alkali metal complexes with strong tolerance to impurities is of great significance for the industrial application of racemic lactide ring-opening polymerization. Summary of the Invention

[0006] One of the objectives of this invention is to disclose a class of ethylidene-bridged aminobisphenol oxyalkali metal complexes.

[0007] The second objective of this invention is to disclose a method for preparing a class of ethylidene-bridged aminobisphenol alkali metal complexes.

[0008] The third objective of this invention is to disclose the application of a class of ethylidene-bridged aminobisphenol alkali metal complexes in lactone polymerization.

[0009] The technical concept of this invention: The steric and electronic effects of Salan-type aminobisphenol ligands can be easily adjusted by changing the substituents at various sites, and the overall synthetic route is relatively simple. They typically have four chelating coordination sites, which is advantageous for stabilizing mononuclear metal centers, but the number of coordination sites is insufficient when synthesizing complexes with polynuclear metal centers. This invention proposes introducing two additional pendant coordination groups into the bridging portion of the Salan ligand, utilizing its characteristic of having six chelating coordination sites to stabilize the binuclear metal center, synthesizing the corresponding binuclear aminobisphenoloxy alkali metal complex, and applying it to lactide polymerization. By changing the types of the two pendant coordination groups in the ligand and the ortho- and para-substituents of the phenoloxy group, the Lewis acidity of the metal center and the steric hindrance around the metal center can be adjusted. Utilizing the synergistic effect of the bimetallic center, the aim is to achieve highly active catalytic ring-opening polymerization of racemic lactide using alkali metal complexes.

[0010] The ethylene-bridged aminobisphenol oxyalkali 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 2Representing C1 to C respectively 20 Alkyl groups with straight, branched, or cyclic structures, C7–C6 30 Mono- or polyaryl substituted alkyl groups, C6–C 18 Aryl groups, or halogens;

[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 or K; n is 0 or 1.

[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 18 Aryl groups, or halogens;

[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.

[0023] The preferred structure of the ethylene-bridged aminobisphenol alkali metal complex is as follows:

[0024]

[0025]

[0026]

[0027] Preferred ethylidene-bridged aminobisphenol alkali metal complexes typically have the following structures for their ethylidene-bridged aminobisphenol ligand compounds:

[0028]

[0029]

[0030] The preparation method of the ethylene-bridged aminobisphenol oxyalkali metal complex (I) of the present invention includes the following steps:

[0031]

[0032] 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 ethylidene-bridged 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 ethylidene-bridged aminobisphenol ligand compound (VII) is then collected from the reaction product.

[0033] In the above preparation method, the reducing agent is a common reducing agent in organic reactions, such as sodium borohydride or lithium aluminum hydride;

[0034] Optionally, the ethylidene-bridged aminobisphenol ligand compound shown in formula (VII) is reacted with a metal hydride in an organic medium at a temperature of 0–100 °C for 2–24 hours, and then the ethylidene-bridged aminobisphenol alkali metal complex (I) is collected from the reaction product.

[0035] In the above preparation method, the substituent R 1 ~R 2 A and the corresponding groups of the ethylidene-bridged aminobisphenol oxyalkali metal complex (I) satisfying the present invention are consistent; the metal hydride MH is NaH or KH.

[0036] The molar ratio of the ethylidene-bridged aminobisphenol ligand compound (VII) to the metal hydride is 1:2.0 to 3.0, preferably 1:2.2 to 2.5.

[0037] The organic medium is selected from one or two of tetrahydrofuran, diethyl ether, toluene, benzene, petroleum ether, and n-hexane.

[0038] The ethylene-bridged aminobisphenol alkali metal complex of the present invention is a highly efficient lactone polymerization catalyst that can be used for the polymerization of L-lactide, D-lactide, rac-lactide, and meso-lactide, and the polymerization methods are solution polymerization and melt polymerization.

[0039] Using the ethylene-bridged aminobisphenol alkali metal complex of the present invention as a catalyst, 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.

[0040] Using the ethylene-bridged aminobisphenol alkali metal complex described in this invention as a catalyst, a certain amount of alcohol can be added as a chain transfer agent to control 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.

[0041] Using the ethylene-bridged aminobisphenol alkali metal complex of the present invention as a catalyst, a certain amount of nitrogen-containing aromatic rings or phosphine oxides can be added as additional neutral ligands to regulate the catalytic activity of the complex during the polymerization of lactones. The molar ratio of catalyst to alcohol, neutral ligand, and lactide monomer during polymerization is 1:1–50:1–50:1–10000, preferably 1:1–20:1–20:20–5000, and most preferably 1:1–10:1–10:100–3000; the nitrogen-containing aromatic rings are C5–C64. 18 The substituted nitrogen-containing aromatic ring is preferably pyridine, 4-(N,N-dimethylamino)pyridine, or bipyridine, and the oxyphosphine compound is C 18 ~C 30 The aryl phosphine oxide, preferably triphenylphosphine oxide.

[0042] Using the ethylene-bridged aminobisphenol alkali metal complex of the present invention as a catalyst, a solvent may also be included when catalyzing lactone polymerization. The solvent is preferably one or more of toluene, tetrahydrofuran, dichloromethane, n-hexane, petroleum ether, m-xylene, o-xylene, mesitylene, and trichlorobenzene. Specifically, it may be one, two, three, four, or five kinds of solvents.

[0043] The catalyst provided by this invention is easy to prepare and has stable properties. Furthermore, the catalyst provided by this invention exhibits high catalytic activity in the ring-opening polymerization of lactide, and high-activity polymerization can be achieved by controlling the ligand structure and polymerization conditions. The invention is further illustrated below with specific embodiments, but the invention is not limited thereto. Detailed Implementation

[0044] Example 1

[0045] Synthesis of ligand L1:

[0046] (1) Synthesis of N,N'-di[(pyridin-2-yl)-methyl]ethylenediamine

[0047]

[0048] 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%).

[0049] (2) Synthesis of ligand L1

[0050]

[0051] 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 C44 H 62 N4O2: C, 77.83; H, 9.20; N, 8.25. Found: C, 77.85; H, 9.25; N, 8.24%.

[0052] Example 2

[0053] Synthesis of ligand L2:

[0054]

[0055] 20 mL of dichloromethane was added to a 50 mL flask containing N,N'-di[(pyridin-2-yl)-methyl]ethylenediamine (approximately 9.57 mmol, 2.32 g) to dissolve it. Then, triethylamine (57.4 mmol, 5.81 g) and 2-bromomethyl-4,6-dicumylphenol (19.1 mmol, 8.08 g) were added sequentially. The reaction was carried out 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 poured off and dried under vacuum to obtain a yellow bubbly powder (4.67 g, 52.6%). 1 H NMR (400MHz, CDCl3, 298K): δ10.00 (br s, 2H, OH), 8.33 (d, 3 J = 4.8 Hz, 2H, ArH), 7.34 (td, 3 J=7.7,1.6Hz,2H,ArH),7.19–7.26(m,7H,ArH),7.01–7.08(m,12H,ArH),7.09–7.01(m,5H,ArH),6.67(s,2H,ArH),6.56(d, 3 J=7.8Hz,2H,ArH),3.48(s,4H,NCH2Ar),3.38(s,4H,NCH2Ar),2.45(s,4H,NCH2CH2N),1.66(s,12H,C(CH3)2Ph),1.63(s,12H,C(CH3)2Ph). 13 C{1H}NMR(101MHz,CDCl3)δ157.28,153.40,151.60,151.40,148.75,140.22,136.79,135.33,128.00,127.75,126.82,126.15 ,125.78,125.52,125.06,124.79,123.97,122.26,121.39,58.99,58.87,49.87,42.55,42.09,31.18,29.55.Anal.Calcd.for C 64 H70 N4O2: C, 82.90; H, 7.61; N, 6.04. Found: C, 82.87; H, 7.38; N, 5.70%.

[0056] Example 3

[0057] Synthesis of ligand L3

[0058]

[0059] 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%.

[0060] Example 4

[0061] Synthesis of ligand L4

[0062]

[0063] 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%). 1 H 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%.

[0064] Example 5

[0065] Synthesis of ligand L5

[0066] (1) Synthesis of N,N'-di[(quinolin-2-yl)-methyl]ethylenediamine

[0067]

[0068] 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.

[0069] (2) Synthesis of ligand L5

[0070]

[0071] 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 66N4O2: C, 80.16; H, 8.54; N, 7.19. Found: C, 79.81; H, 8.36; N, 6.94%.

[0072] Example 6

[0073] Synthesis of ligand L6

[0074] (1) Synthesis of N,N'-di[(N-methylbenzimidazol-2-yl)-methyl]ethylenediamine

[0075]

[0076] 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.

[0077] (2) Synthesis of ligand L6

[0078]

[0079] 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). 13C 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 68 N6O2: C, 76.49; H, 8.73; N, 10.70. Found: C, 76.61; H, 8.48; N, 10.83%.

[0080] Example 7

[0081] Synthesis of ligand L7

[0082] (1)N 1 N 1 '-(ethane-1,2-diyl)bis(N 2 N 2 Synthesis of 1,2-dimethylethane-1,2-amine

[0083]

[0084] Diethyl oxalate (60 mmol, 2.65 g), anhydrous ethanol (50 mL), and N,N-dimethylethylenediamine (30 mmol, 2.20 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 product N. 1 N 1 '-(ethylenediamide-1,2-diyl)bis(N 2 N 2 (-Dimethylethane-1,2-amine)(4.14 g, 95%).

[0085] Under an argon atmosphere, oxalamide (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(N2 N 2 (-Dimethylethane-1,2-amine)(2.56 g, 84.3%).

[0086] (2) Synthesis of ligand L7

[0087]

[0088] 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 62N4O2:C,77.83;H,9.20;N,8.25.Found:C,77.74;H,9.38;N,8.31.

[0089] Example 8

[0090] Synthesis of alkali metal complex Na1

[0091]

[0092] 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 (1.5 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Excess sodium hydride and a small amount of impurities were removed by filtration, and the filtrate was dried under vacuum to obtain a yellow foamy solid. Tetrahydrofuran and n-hexane were added for recrystallization to give a pale yellow solid (214 mg, 59.4%).

[0093] 1 H NMR(400MHz,C6D6)δ7.56–7.67(m,4H,ArH),7.05(d, 3 J = 2.6 Hz, 2H, ArH), 6.79 (t, 3 J=7.6Hz,2H,ArH),6.50–6.37(m,2H,ArH),6.30–6.16(m,2H,ArH),4.29–4.06(m,4H,ArCH2N),3.63–3.39(m,8H,THF),2.90(d, 2 J = 8.8 Hz, 2H, ArCH2N), 2.45 (d, 2 J = 13.8 Hz, 2H, ArCH2N), 2.22 (d, 2 J=10.5Hz,2H,NCH2CH2N),2.02(s,18H,C(CH3)3),1.50(s,18H,C(CH3)3),1.39(m,8H,THF). 13C NMR(101MHz,C6D6)δ167.87,159.34,150.00,137.47(toluene),136.55,130.57( toluene),127.37,125.68(toluene),123.88,123.75,122.95,121.97(AllAr-C), 67.79(THF),61.50(ArCH2),58.52(ArCH2),53.60(NCH2CH2N),36.04(C(CH3)3),3 4.11(C(CH3)3),32.68(C(CH3)3),30.28(C(CH3)3),25.72(THF).Anal.Calcd.for C 52 H 76 N4O4Na2·0.4C7H8: C, 72.81; H, 8.83; N, 6.20. Found: C, 73.20; H, 8.70; N, 6.18%.

[0094] Example 9

[0095] Synthesis of alkali metal complex Na2

[0096]

[0097] Under argon protection, ligand L2 (0.500 mmol, 464 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.5 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Excess sodium hydride and a small amount of impurities were removed by filtration, and the filtrate was dried under vacuum to obtain a yellow foamy solid. Tetrahydrofuran and n-hexane were added for recrystallization to give a pale yellow solid (253 mg, 52.3%).

[0098] 1 H NMR (400MHz, C6D6) δ 7.61 (d, 4 J=2.7Hz,2H,ArH),7.58–7.51(m,4H,ArH),7.48(dd, 3 J = 7.7, 1.6 Hz, 4H, ArH), 7.06 (t, 3 J = 7.2 Hz, 6H, ArH), 6.98 (d, 3 J = 7.6 Hz, 2H, ArH), 6.82 (d, 4 J = 2.7 Hz, 2H, ArH), 6.79 (td, 3 J = 7.8, 2.0 Hz, 2H, ArH), 6.39 (d, 3J = 7.7 Hz, 2H, ArH), 6.28 (dd, 3 J = 7.6, 4.9 Hz, 2H, ArH), 3.82 (d, 2 J = 10.6 Hz, 2H, NCH2Ar), 3.55 (d, 2 J = 13.5 Hz, 2H, NCH2Ar), 2.54 (d, 2 J=8.3Hz,2H,NCH2CH2N),2.38(s,6H,(CPh(CH3)2),2.15(d, 2 J=13.5Hz,2H,NCH2Ar),1.83(s,18H,C(CH3)3),1.73(s,6H,CPh(CH3)),1.21(d, 2 J = 8.3 Hz, 2H, NCH2CH2N). 13 C NMR (101MHz, C6D6) δ166.26,160.10,156.79,153.62,149.99,137.43,136.42,129.96,125.83,125.26,124.55,124.09,123.28,122.00 (All Ar-C),60.64(ArC),58.73(ArCH2),53.17(ArCH2),42.99(NCH2CH2N),42.58(CPh(C H3)2),33.67(CPh(CH3)2),32.14(CPh(CH3)2),32.01(CPh(CH3)2).Anal.Calcd.for C 64 H 68 N4O2Na2:C,79.15;H,7.06;N,5.77.Found:C,79.20;H,7.40;N,6.08%.

[0099] Example 10

[0100] Synthesis of alkali metal complex Na3

[0101]

[0102] Under argon protection, ligand L3 (0.500 mmol, 318 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.5 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Excess sodium hydride and a small amount of impurities were removed by filtration, and the filtrate was dried under vacuum to obtain a yellow foamy solid. Tetrahydrofuran and n-hexane were added for recrystallization to give a white solid (167 mg, 49.24%).

[0103] 1 H NMR (400MHz, C6D6, 298K): δ7.64 (dd, 3 J = 5.2, 1.8 Hz, 2H, ArH), 7.58 (d, 4 J = 2.9 Hz, 2H, ArH), 7.03 (d, 4 J = 2.9 Hz, 2H, ArH), 6.84 (td, 3 J = 7.4, 1.9 Hz, 2H, ArH), 6.45 (d, 3 J = 7.7 Hz, 2H, ArH), 6.32 (dd, 3 J=7.6,4.9Hz,2H,ArH),3.63–3.39(m,4H,THF),3.96(d, 2 J = 10.9 Hz, 2H, NCH2Ar), 3.85 (d, 2 J = 13.9 Hz, 2H, NCH2Ar), 2.70 (d, 2 J=9.0Hz,2H,NCH2CH2N),2.24(d, 2 J = 13.9 Hz, 2H, NCH2Ar), 1.96 (d, 2 J=10.9Hz,2H,NCH2Ar),1.39(m,4H,THF),1.36(d, 2 J=9.0Hz,2H,NCH2CH2N),1.79(s,18H,C(CH3)3).Anal.Calcd.for C 36 H 42 Cl2N4O2Na2C4H8O: C, 63.91; H, 6.70; N, 7.45. Found: C, 63.36; H, 6.90; N, 6.96%.

[0104] Example 11

[0105] Synthesis of alkali metal complex Na4

[0106]

[0107] Under argon protection, ligand L4 (0.500 mmol, 359 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.5 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Excess sodium hydride and a small amount of impurities were removed by filtration, and the filtrate was dried under vacuum to obtain a yellow foamy solid. Tetrahydrofuran and n-hexane were added and recrystallized to give a pale yellow solid (191 mg, 50.16%).

[0108] 1 H NMR (400MHz, C6D6, 298K): δ7.97(d, 3 J = 4.5 Hz, 2H, ArH), 7.60 (d, 3 J = 7.5 Hz, 4H, ArH), 7.22(t, 3 J=7.5Hz,4H,ArH),7.10–7.05(m,4H,ArH),6.90(s,2H,ArH),6.76(td, 3 J = 7.6, 2Hz, 2H, ArH), 6.31(d, 3 J=7.8Hz,2H,ArH),6.24–6.16(m,2H,ArH),4.01(d, 2 J=11.6Hz,2H,NCH2Ar),3.59–3.52(m,5H,THF),3.20(s,4H,NCH2Ar),2.52(d, 2 J=11.6Hz,4H,NCH2Ar,NCH2CH2N),2.37(s,2H,NCH2CH2N),1.46(s,18H,C(CH3)3),1.45–1.33(m,5H,THF). 13 CNMR(101MHz,C6D6)δ165.02,160.12,148.38,144.59,135.23,131.41,129.28,128.91,126.72,126.23,124.93,122.34,120.74(All Ar-C),67.81(THF),62.30(ArC),61.53(ArC),56.92(ArC),33.71(NCH2CH2N),32.53(C(CH3)3),25.79(THF),1.42.Anal.Calcd.forC 48 H 52 N4O2Na2·1.25C4H8O:C,74.62;H,7.33;N,6.57.Found:C,74.59;H,6.98;N,6.97%.

[0109] Example 12

[0110] Synthesis of alkali metal complex Na5

[0111]

[0112] Under argon protection, ligand L5 (0.500 mmol, 390 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.5 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Excess sodium hydride and a small amount of impurities were removed by filtration, and the filtrate was dried under vacuum to obtain a yellow foamy solid. Tetrahydrofuran and n-hexane were added for recrystallization to give a white solid (225 mg, 54.71%).

[0113] 1 H NMR (400MHz, C6D6): δ 7.92 (d, 3 J = 8.4 Hz, 2H, ArH), 7.71 (d, 4 J = 2.8 Hz, 2H, ArH), 7.33 (d, 3 J = 8.5 Hz, 2H, ArH), 7.19 (dd, 3 J = 8.4, 1.4 Hz, 2H, ArH), 7.06 (d, 4 J = 2.7 Hz, 2H, ArH), 7.02 (ddd, 3 J=8.5,6.9,1.5Hz,2H,ArH),6.96–6.87(ddd, 3 J=8.0,6.9,1.2Hz,2H,ArH),6.52(d, 3 J = 8.4 Hz, 2H, ArH), 4.63 (d, 2 J = 10.7 Hz, 2H, NCH2Ar), 4.40 (d, 2 J=15.2Hz,2H,NCH2Ar),3.59-3.45(m,8H,THF),3.14(d, 2 J=8.9Hz,2H,NCH2CH2N),2.69(d, 2 J = 15.2 Hz, 2H, NCH2Ar), 2.20 (d, 2 J=10.7Hz,2H,NCH2Ar)2.13(s,18H,C(CH3)3),1.53(s,18H,C(CH3)3),1.42-1.31(m,8H,THF).Anal.Calcd.for C 52 H 64 Cl2N4Na2O2·2C4H8O: C, 74.50; H, 8.50; N, 5.79. Found: C, 74.90; H, 8.50; N, 5.79%.

[0114] Example 13

[0115] Synthesis of alkali metal complex Na6

[0116]

[0117] Under argon protection, ligand L6 (0.500 mmol, 394 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.5 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Excess sodium hydride and a small amount of impurities were removed by filtration, and the filtrate was dried under vacuum to obtain a yellow foamy solid. Tetrahydrofuran and n-hexane were added for recrystallization to give a white solid (195 mg, 45.36%).

[0118] 1 H NMR (400MHz, C6D6): δ 7.71 (d, 4 J = 2.8 Hz, 2H, ArH), 7.33 (d, 3 J = 8.5 Hz, 2H, ArH), 7.19 (dd, 3 J = 8.4, 1.4 Hz, 2H, ArH), 7.06 (d, 4 J = 2.7 Hz, 2H, ArH), 7.02 (ddd, 3 J=8.5,6.9,1.5Hz,2H,ArH),6.52(d, 3 J = 8.4 Hz, 2H, ArH), 4.63 (d, 2 J = 10.7 Hz, 2H, NCH2Ar), 4.40 (d, 2 J=15.2Hz,2H,NCH2Ar),3.59-3.45(m,8H,THF),3.14(d, 2 J=8.9Hz,2H,NCH2CH2N),2.69(d, 2 J=15.2Hz,2H,NCH2Ar),2.53(s,6H,NCH3),2.20(d, 2 J=10.7Hz,2H,NCH2Ar),2.13(s,18H,C(CH3)3),1.53(s,18H,C(CH3)3),1.42-1.31(m,8H,THF).Anal.Calcd.for C 52 H 64 Cl2N4Na2O2·2C4H8O: C, 74.50; H, 8.50; N, 5.79. Found: C, 74.90; H, 8.50; N, 5.79%.

[0119] Example 14

[0120] Synthesis of alkali metal complex Na7

[0121] Under argon protection, ligand L7 (0.500 mmol, 339 mg) was added to a 50 mL Schlenk flask and dissolved in 15 mL of anhydrous tetrahydrofuran. Then, NaH (1.5 mmol, 36 mg) was slowly added, and the reaction was carried out at room temperature for 12 h. Excess sodium hydride and a small amount of impurities were removed by filtration, and the filtrate was dried under vacuum to obtain a yellow foamy solid. Tetrahydrofuran and n-hexane were added and recrystallized to give a white solid (153 mg, 42.36%).

[0122]

[0123] 1 H NMR (400MHz, C6D6): δ7.62-7.56(d,J=7.2Hz,4H,ArH),7.38(s,2H,ArH),7.13–6.99(m,6H,ArH),3.59–3.49(m,3H,THF),3.62(s,2H,NCH2Ar) ,2.85–2.45(m,6H,NCH2CH2N),2.42-2.12(m,4H,NCH2Ar,NCH2CH2N),1.76(s,12H,N(CH3)2),1.50(s,18H,C(CH3)3),1.44–1.36(m,3H,THF). 13 C NMR (101MHz, C6D6) δ164.84,145.09,132.76,130.25,129.64,129.42,127.13,126.27,125.59(All Ar-C),67.82(THF),59.16(N-CH2-Ar),53.32(NCH2CH2N),45.51(N(CH3)2),33.87(C(CH3)3),32.46(C(CH3)3),25.79(THF).Calcd.for C 48 H 52 N4O2Na2·0.64C4H8O:C,72.71;H,8.53;N,7.28.Found:C,72.21;H,8.38;N,7.79%.

[0124] Example 15

[0125] Synthesis of alkali metal complex K1

[0126]

[0127] 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, 36 mg) was then slowly added, and the reaction was carried out at room temperature for 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 (283 mg, 75.0%).

[0128] 1 H NMR (400MHz, THF) δ 8.27 (d, 2 J=3.9Hz,4H,ArH),7.39(td,J=7.6,1.7Hz,4H,ArH),6.98(d, 3 J=7.7Hz,4H,ArH),6.93–6.87(m,8H,ArH),6.75(d, 2 J=2.7Hz,4H,ArH),1.40(s,36H,C(CH3)3),1.31(m,1.2H,0.2pentane),1.14(s,36H,C(CH3)3),0.85(m,1.2H,0.2pentane). 13 C NMR(101MHz,THF)δ168.35,161.01,149.81,136.29,136.07,127.80,127.33,124.75,124.27,122.63,121.82(All Ar-C),60.45(ArCH2),59.05(ArCH2),54.88(NCH2CH2N),35.67(C(CH3)3),33.96(C(CH3)3),32.56(C(CH3)3),30.21(C(CH3)3).Anal.Calcd.for C 88 H 120 N8O4K4·0.4C5H 12 :C,70.23;H,8.17;N,7.28. Found:C,69.74;H,8.04;N,7.44%.

[0129] Example 16

[0130] 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 a benzyl alcohol toluene solution. 0.5 mL of a Na1 catalyst toluene solution was added to the polymerization flask. The concentrations were: [rac-LA]0 = 1.0 M, [Na]0 = 0.002 M, [BnOH]0 = 0.002 M, and [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 74 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 product was then vacuum dried for 24 h. The conversion rate was 96%. n =7.69×10 4 g / mol, molecular weight distribution PDI = 1.67, isotacticity P m =0.58.

[0131] Example 17

[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 toluene, followed by 0.2 mL of a benzyl alcohol toluene solution. 0.5 mL of a Na1 catalyst toluene solution was added to the polymerization flask. The concentrations were: [rac-LA]0 = 1.0 M, [Na]0 = 0.002 M, [BnOH]0 = 0.004 M, and [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 59 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 product was then vacuum dried for 24 h. The conversion rate was 95%. n =3.54×10 4 g / mol, molecular weight distribution PDI = 1.57, isotacticity P m =0.62.

[0133] Example 18

[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. Then, 0.2 mL of a toluene solution of benzyl alcohol and 0.2 mL of a toluene solution of 4-(N,N-dimethylamino)pyridine (DMAP) were added. 0.5 mL of a toluene solution of catalyst Na1 was added to the polymerization flask. The reaction mixture was: [rac-LA]0 = 1.0 M, [Na]0 = 0.002 M, [BnOH]0 = 0.004 M, [DMAP]0 = 0.004 M, and [rac-LA]0:[Na]0:[BnOH]0:[DMAP] = 500:1:2:2. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was carried out for 90 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 99%. n =3.57×10 4 g / mol, molecular weight distribution PDI = 1.62, isotacticity P m =0.59.

[0135] Example 19

[0136] Except for replacing the monomer with L-LA, the other operations were the same as in Example 17. After reacting for 59 seconds, the conversion rate was 99%. n =4.87×10 4 g / mol, molecular weight distribution PDI = 1.61, isotacticity P m =1.

[0137] Example 20

[0138] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to a polymerization flask, followed by 0.2 mL of a benzyl alcohol toluene solution and 0.3 mL of a DMAP toluene solution. 0.5 mL of a Na1 catalyst toluene solution was added to the polymerization flask. The concentrations were: [rac-LA]0 = 1.0 M, [Na]0 = 0.002 M, [BnOH]0 = 0.004 M, [DMAP]0 = 0.008 M, and [rac-LA]0:[Na]0:[BnOH]0:[DMAP] = 500:1:2:4. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was carried out for 105 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 95%. n =4.90×10 4 g / mol, molecular weight distribution PDI = 1.36, isotacticity P m =0.56.

[0139] Example 21

[0140] Except for replacing DMAP with dipyridine (DiPy), the other operations were the same as in Example 18. After reacting for 128 seconds, the conversion rate was 96%, M n =7.50×10 4 g / mol, molecular weight distribution PDI = 1.39, isotacticity P m =0.57.

[0141] Example 22

[0142] Except for replacing DMAP with triphenylphosphine oxide (TPPO), the other operations were the same as in Example 18. After reacting for 67 seconds, the conversion rate was 96%, M n =5.07×10 4 g / mol, molecular weight distribution PDI = 1.53, isotacticity P m =0.57.

[0143] Example 23

[0144] 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 a toluene solution of DMAP. 0.5 mL of a toluene solution of catalyst Na1 was added to the polymerization flask. [rac-LA]0 = 1.0 M, [Na]0 = 0.002 M, [DMAP]0 = 0.004 M, [rac-LA]0:[Na]0:[DMAP] = 500:1:2. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was carried out for 405 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 =10.27×10 4 g / mol, molecular weight distribution PDI = 1.35, isotacticity P m =0.57.

[0145] Example 24

[0146] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to a polymerization flask, followed by 0.5 mL of a benzyl alcohol toluene solution, then 0.2 mL of a DMAP toluene solution, and finally 0.05 mL of toluene. 0.25 mL of a Na1 catalyst toluene solution was added to the polymerization flask. The reaction mixture was: [rac-LA]0 = 1.0 M, [Na]0 = 0.001 M, [BnOH]0 = 0.01 M, [DMAP]0 = 0.002 M, and [rac-LA]0:[Na]0:[BnOH]0:[DMAP]0 = 1000:1:10:2. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was allowed to proceed for 72 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 94%. n =2.71×10 4 g / mol, molecular weight distribution PDI = 1.55, isotacticity P m =0.62.

[0147] Example 25

[0148] Except for the temperature being changed to -40±1℃, the other operations were the same as in Example 18. After reacting for 31 minutes, the conversion rate was 70%, M n =6.80×10 4 g / mol, molecular weight distribution PDI = 1.44, isotacticity P m =0.68.

[0149] Example 26

[0150] Except for replacing the catalyst with Na2, the other operations were the same as in Example 17. After reacting for 501 seconds, the conversion rate was 84%, M n =3.21×10 4 g / mol, molecular weight distribution PDI = 1.61, isotacticity P m =0.59.

[0151] Example 27

[0152] Except for replacing the catalyst with Na2, the other operations were the same as in Example 18. After reacting for 840 seconds, the conversion rate was 86%, M n =3.17×10 4 g / mol, molecular weight distribution PDI = 1.87, isotacticity P m =0.61.

[0153] Example 28

[0154] Except for replacing the catalyst with Na3, the other operations were the same as in Example 17. After reacting for 480 seconds, the conversion rate was 93%, M n =4.52×104 g / mol, molecular weight distribution PDI = 1.93, isotacticity P m =0.57.

[0155] Example 29

[0156] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to a polymerization flask and dissolved in 0.1 mL of toluene, followed by 0.4 mL of a benzyl alcohol toluene solution. 0.5 mL of a Na3 catalyst toluene solution was added to the polymerization flask. The concentrations were: [rac-LA]0 = 1.0 M, [Na]0 = 0.002 M, [BnOH]0 = 0.008 M, and [rac-LA]0:[Na]0:[BnOH]0 = 500:1:4. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was carried out for 210 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 94%, M n =3.54×10 4 g / mol, molecular weight distribution PDI = 1.67, isotacticity P m =0.64.

[0157] Example 30

[0158] Except for replacing the catalyst with Na4, the other operations were the same as in Example 17. After reacting for 530 seconds, the conversion rate was 87%, M n =4.20×10 4 g / mol, molecular weight distribution PDI = 1.71, isotacticity P m =0.56.

[0159] Example 31

[0160] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to the polymerization flask, dissolved in 0.2 mL of toluene, and then 0.3 mL of a toluene solution of isopropanol was added. 0.5 mL of a toluene solution of catalyst Na₄⁻ was added to the polymerization flask. [rac-LA]₀ = 1.0 M, [Na]₀ = 0.002 M, [ i PrOH]0=0.006M,[rac-LA]0:[Na]0:[ i PrOH]0 = 500:1:3. The reaction temperature was controlled at 25±1℃, and the reaction time was 210 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 product was then vacuum dried for 24 hours. The conversion rate was 90%, M n =3.45×10 4 g / mol, molecular weight distribution PDI = 1.68, isotacticity P m =0.60.

[0161] Example 32

[0162] Except for replacing the catalyst with Na4, the other operations were the same as in Example 29. After reacting for 255 seconds, the conversion rate was 93%, M n =2.56×10 4 g / mol, molecular weight distribution PDI = 1.71, isotacticity P m =0.59.

[0163] Example 33

[0164] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to a polymerization flask and dissolved in 0.5 mL of toluene. 0.5 mL of a toluene solution of catalyst Na5 was added to the polymerization flask. [rac-LA]0 = 1.0 M, [Na]0 = 0.002 M, [rac-LA]0:[Na]0 = 500:1. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was carried out for 550 seconds. The reaction was terminated by adding petroleum ether. The solvent was removed, and the residue was dissolved in dichloromethane. Methanol was added to precipitate the polymer. The product was dried under vacuum for 24 h. The conversion rate was 92%. n =1.20×10 5 g / mol, molecular weight distribution PDI = 1.67, isotacticity P m =0.54.

[0165] Example 34

[0166] Except for replacing the catalyst with Na5, the other operations were the same as in Example 17. After reacting for 125 seconds, the conversion rate was 92%, M n =4.73×10 4 g / mol, molecular weight distribution PDI = 1.68, isotacticity P m =0.56.

[0167] Example 35

[0168] Except for replacing the catalyst with Na5, the other operations were the same as in Example 29. After 70 seconds of reaction, the conversion rate was 90%, M n =2.75×10 4 g / mol, molecular weight distribution PDI = 1.60, isotacticity P m =0.60.

[0169] Example 36

[0170] Under argon protection, racemic lactide (0.288 g, 2.0 mmol) was added to a polymerization flask and dissolved in 1.65 mL of toluene, followed by 0.1 mL of a benzyl alcohol toluene solution. 0.25 mL of a Na₂O toluene solution was added to the polymerization flask. The concentrations were: [rac-LA]₀ = 1.0 M, [Na]₀ = 0.0005 M, [BnOH]₀ = 0.001 M, and [rac-LA]₀:[Na]₀:[BnOH]₀ = 2000:1:2. The reaction temperature was controlled at 25 ± 1 °C, and the reaction was carried out for 350 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 97%. n =1.21×10 5 g / mol, molecular weight distribution PDI = 1.66, isotacticity P m =0.58.

[0171] Example 37

[0172] Except for the temperature being changed to -20±1℃, the other operations were the same as in Example 34. After reacting for 40 minutes, the conversion rate was 90%, M n =5.53×10 4 g / mol, molecular weight distribution PDI = 1.78, isotacticity P m =0.66.

[0173] Example 38

[0174] Except for the temperature being changed to -20±1℃, the other operations were the same as in Example 35. After reacting for 28 minutes, the conversion rate was 93%, M n =2.88×10 4 g / mol, molecular weight distribution PDI = 1.66, isotacticity P m =0.65.

[0175] Example 39

[0176] Except for replacing the catalyst with Na6, the other operations were the same as in Example 17. After reacting for 155 seconds, the conversion rate was 90%, M n =4.55×10 4 g / mol, molecular weight distribution PDI = 1.69, isotacticity P m =0.56.

[0177] Example 40

[0178] Except for replacing the catalyst with Na6, the other operations were the same as in Example 29. After 100 seconds of reaction, the conversion rate was 90%, M n =2.67×10 4 g / mol, molecular weight distribution PDI = 1.65, isotacticity Pm =0.60.

[0179] Example 41

[0180] Except for replacing the catalyst with Na7, the other operations were the same as in Example 17. After reacting for 480 seconds, the conversion rate was 95%, M n =4.63×10 4 g / mol, molecular weight distribution PDI = 1.68, isotacticity P m =0.53.

[0181] Example 42

[0182] Except for replacing the catalyst with Na7, the other operations were the same as in Example 29. After reacting for 227 seconds, the conversion rate was 95%, M n =2.70×10 4 g / mol, molecular weight distribution PDI = 1.68, isotacticity P m =0.60.

[0183] Example 43

[0184] Under argon protection, racemic lactide (0.144 g, 1.0 mmol) was added to a polymerization flask and dissolved in 0.65 mL of toluene, followed by 0.1 mL of a benzyl alcohol toluene solution. 0.25 mL of a toluene solution of catalyst K1 was added to the polymerization flask. The reaction mixture was: [rac-LA]0 = 1.0 M, [K]0 = 0.001 M, [BnOH]0 = 0.002 M, [rac-LA]0:[K]0:[BnOH]0 = 1000:1:2. The reaction temperature was controlled at 25 ± 1 °C, and the reaction time was 45 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 89%, M n =8.40×10 4 g / mol, molecular weight distribution PDI = 1.85, isotacticity P m =0.62.

[0185] Example 44

[0186] Except for replacing the monomer with L-lactide, the other operations were the same as in Example 34. After reacting for 135 seconds, the conversion rate was 95%, M n =3.68×10 4 g / mol, molecular weight distribution PDI = 1.92, isotacticity P m =1.

[0187] Example 45

[0188] Under argon protection, racemic lactide (0.288 g, 1.0 mmol) was added to a polymerization flask, followed by 0.1 mL of a benzyl alcohol toluene solution. 0.1 mL of a Na1 toluene solution 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 128 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 =7.28×10 4 g / mol, molecular weight distribution PDI = 1.79, isotacticity P m =0.54.

[0189] 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. An ethylene-bridged aminobisphenol O-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 12 Straight-chain and branched alkyl groups, C7~C 20 Mono- or polyaryl substituted alkyl groups, C6~C 12 Aryl groups, or halogens; 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; n is 0 or 1.

2. The ethylene-bridged aminobisphenol alkali metal complex (I) according to claim 1, characterized in that, R 1 ~R 2 The compounds are methyl, isopropyl, tert-butyl, cumyl, triphenylmethyl, phenyl, and halogen.

3. A method for preparing the ethylene-bridged aminobisphenol oxyalkali metal complex (I) according to any one of claims 1 to 2, comprising the following steps: 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 the reaction is carried out at 0–90 °C for 2–72 hours. The ethylidene-bridged 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, and then 2-bromomethyl-4,6-disubstituted phenol (IX) is added, and the reaction is carried out at 0–90 °C for 2–72 hours. The ethylidene-bridged aminobisphenol ligand compound (VII) is then collected from the reaction product. The ethylidene-bridged aminobisphenol ligand compound shown in formula (VII) is reacted with a metal hydride in an organic medium at a temperature of 0 to 100 ºC for 2 to 24 hours. Then, the ethylidene-bridged aminobisphenol alkali metal complex (I) is collected from the reaction product. Substituent R in the reaction formula 1 ~R 2 A is consistent with the corresponding groups of the ethylene-bridged aminobisphenoloxy alkali metal complex (I) according to any one of claims 1 to 2; A is consistent with the corresponding groups of the ethylene-bridged aminobisphenoloxy alkali metal complex (I) according to claim 1. The metal hydride MH is NaH or KH.

4. The method according to claim 3, characterized in that, The molar ratio of the ethylidene-bridged aminobisphenol ligand compound (VII) to the metal hydride is 1:2.0~3.0; 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.

5. The method according to claim 3, characterized in that, The molar ratio of the ethylidene-bridged aminobisphenol ligand compound (VII) to the metal hydride is 1:2.2~2.

5.

6. The application of the ethylene-bridged aminobisphenol alkali metal complex according to any one of claims 1 to 2, characterized in that, Used for the ring-opening polymerization of lactones, wherein the lactones are selected from L-lactide, D-lactide, rac-lactide, and meso-lactide.

7. The application according to claim 6, characterized in that, Using the ethylene-bridged aminobisphenol alkali metal complex according to any one of claims 1 to 2 as a catalyst, lactide is polymerized, wherein the molar ratio of catalyst to monomer during polymerization is 1:1 to 10000.

8. The application according to claim 6, characterized in that, Using the ethylene-bridged aminobisphenol alkali metal complex according to any one of claims 1-2 as a catalyst, lactide is polymerized at 70-180 °C in the presence of an alcohol, wherein the molar ratio of catalyst to alcohol and lactide during polymerization is 1:1-50:1-10000; wherein the alcohol is C1-C6. 10 Alkyl alcohols with straight-chain, branched, or cyclic structures, C7~C 20 Mono- or polyaryl-substituted alkyl alcohols.

9. The application according to claim 6, characterized in that, Using the ethylene-bridged aminobisphenol alkali metal complex according to any one of claims 1-2 as a catalyst, and adding a nitrogen-containing aromatic ring compound or an oxophosphorus compound as an additional neutral ligand, lactide is polymerized at 70-180 °C. During polymerization, the molar ratio of catalyst to neutral ligand and lactide is 1:1-50:1-10000; the nitrogen-containing aromatic ring compound is C5-C6. 18 The substituted nitrogen-containing aromatic ring; the phosphine oxide compound is C 18 ~C 30 arylphosphine oxide.

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