CN114507246A - A class of benzimidazole substituted aminophenoloxyzinc halide and its preparation method and application - Google Patents

Abstract

The invention discloses benzimidazole substituted aminophenol oxy zinc halide, a preparation method thereof and application thereof in catalyzing lactone ring-opening polymerization. The preparation method comprises the following steps: the neutral ligand firstly reacts with a hydrogen-withdrawing reagent to generate metal salt of the ligand, then the metal salt reacts with a metal raw material compound in an organic medium, and a target compound is obtained through recrystallization. The complex is a high-efficiency lactone ring-opening polymerization catalyst, and can be used for catalyzing the polymerization reaction of lactones such as lactide and the like to obtain a cyclic polymer; particularly has good catalytic effect on rac-lactide polymerization. The benzimidazole substituted aminophenol oxygen radical zinc halide has obvious advantages: easily available raw materials, simple synthetic route, high product yield, high catalytic activity and stereoselectivity, and high regularityAnd a cyclic polyester material of high molecular weight, and the catalyst has good tolerance to impurities and can meet the needs of the industrial sector. The structural formula is shown as follows.

Description

A class of benzimidazole substituted aminophenoloxyzinc halide and its preparation method and application

technical field

The present invention relates to a class of benzimidazole substituted aminophenoxyzinc halides and the use of such complexes in the polymerization of lactones.

Background technique

In recent years, with the rapid economic development of various countries, the global demand for oil resources has greatly increased, resulting in serious resource crisis and environmental problems. Among them, the main consumption of petroleum resources is the use of downstream olefin products, such as the synthesis of polymer materials such as polyethylene and polypropylene. As a new type of green material, polyester has gradually attracted people's attention. For example, polylactide with good biocompatibility can be used as raw material from waste straws of corn, wheat and other plants, and has good degradability. It is degraded into water and carbon dioxide by microorganisms in nature and participates in the photosynthesis of plants. It is an environmentally friendly material. In addition, polylactide has excellent physical and mechanical properties, and can be used in various plastic products, fast food lunch boxes, and civilian cloth from industry to civilian use.

At present, polylactide is mainly synthesized by indirect method, that is, polylactide with high molecular weight can be obtained by controlled polymerization of lactide dimer-lactide under the catalysis of a specific catalyst. Equivalent amounts of L-lactide (L-LA) and D-lactide (D-LA) were mixed to obtain rac-lactide (rac-LA). Polylactides with different stereoconfigurations can be polymerized to form random, heterotactic, syndiotactic or isotactic polylactides, while polylactides with different regularities exhibit different physical and mechanical properties. Among them, the hightactic block polylactide obtained by isotactic selective polymerization of rac-lactide can form a three-dimensional composite structure, the melting point can reach 230 °C, and it has good mechanical properties. The chain structure of polylactide can be a linear structure or a cyclic structure, wherein the cyclic polymer exhibits different physical and chemical properties from the linear polymer because it has no end groups. Specifically, cyclic polymers have high glass transition temperature, small hydrodynamic radius, special self-assembly ability, and other performance advantages, so they have unique potential applications in materials science and biomedicine. Although there have been some reports on cyclic polymers, the catalysts used in the polymerization are generally sensitive, and the controlled synthesis of higher molecular weight, hypertactic block cyclic polylactides has not yet been achieved. Metal complex catalysts have become the most important catalysts for catalyzing the polymerization of lactide monomers to obtain polylactide due to their higher activity and better selectivity. Among them, zinc element is an essential element of human body, and its corresponding complexes show high activity and isotactic selectivity in lactide ring-opening polymerization, so it has gradually become the focus of people's attention. But so far, there is no report on the single use of metal zinc catalyst to realize the polymerization of lactide to obtain cyclic polymer.

In 2006, the Waymouth group used N-heterocyclic carbene organic catalysts to achieve the synthesis of cyclic polylactide through the ring expansion mechanism of zwitterions, but because the catalyst was too sensitive, it could only catalyze 200 equivalents of purified rac- Lactide to give random polylactide with a molecular weight of 2.6×10 ⁴ g/mol (Angew. Chem. Int. Ed., 2007, 46, 2627-2630). In 2008, the Kricheldorf group reported an N-methylimidazole catalyst system that produces cyclic polylactide at high temperature via zwitterion end-to-end cyclization, but only as oligomers (Macromolecules., 2008, 41, 7812–7816 ). In 2013, the Getzler group used (tBu- ^SalAmEE )Al as a catalyst to obtain cyclic polylactide through ring expansion and intramolecular transesterification, but only a molecular weight of 2.0×10 ⁴ g/mol was obtained. Random polymers (Macromolecules, 2013, 46, 3273-3279). In the same year, Bourissou's group used a catalytic system combining Zn(C ₆ F ₅ ) ₂ and an organic base to catalyze the ring-opening polymerization of rac-lactide to obtain a random cyclic polylactide with a molecular weight of 4.5×10 ⁴ g/mol (J . Am. Chem. Soc., 2013, 135, 13306-13309). Subsequently, Otero's group reported a series of metal-aluminum complex catalysts, which catalyzed the ring-opening polymerization of ε-caprolactone and showed good controllability (PDI<1.30) to obtain cyclic polymers (Macromolecules, 2013, 46, 6388–6394). In 2014, Du's group used ortho-substituted oxazole-derived zinc complexes of chiral β-diimine-like ligands as catalysts to catalyze the ring-opening polymerization of rac-lactide to obtain isotactic polylactide, The highest isotacticity is 0.91, but the activity is unsatisfactory (ACS Macro Lett., 2014, 3, 689–692). In 2015, the Phomphrai group developed a series of tin catalysts with various alkoxy side chains to obtain high molecular weight cyclic polyesters (M _n < 5.4×10 ⁴ g/mol through the intramolecular intramolecular cross-linking of alkoxy side chains. ) (Dalton Trans., 2015, 44, 12357–12364). In 2017, Wu's group reported a series of complexes of sodium and potassium sulfamate, which can catalyze the ring-opening polymerization of rac-lactide to obtain cyclic polymers without adding alcohol, but the molecular weight is only 1.4 × 10. ⁴ g/mol, and the isotacticity is only 0.63 (Macromolecules, 2017, 50, 83-96). In 2019, the Scheliga group used tributyltin chloride, dibutyltin dichloride and butyltin trichloride as catalysts for the ring-opening polymerization of L-lactide, but only the least reactive catalyst, _Bu3SnCl , produced molecular weights in the range of (1.4 to 5.4). )×10 ⁴ g/mol range of random cyclic polymers (Polym. Chem., 2019, 57, 952-960). In 2019, Ma's group synthesized benzimidazole-substituted aminophenoloxyzinc complexes, which can catalyze the ring-opening polymerization of rac-lactide with high tactical selectivity to obtain linear polylactide (Chem. Commun., 2019, 55, 10112 -10115).

At present, researchers have synthesized a variety of catalysts in the field of cyclic polyester synthesis, but these catalysts generally have shortcomings such as being sensitive to impurities, so they can only catalyze monomers that have undergone multi-step purification, which makes it difficult to popularize in industry. Moreover, when catalyzing lactones to synthesize cyclic polyesters, only low molecular weight and approximately random cyclic polyesters can be obtained, which limits the application of cyclic polyester materials in practical production. In view of the excellent properties of cyclic polyesters, a metal zinc catalyst with high activity, high tactical selectivity and insensitivity to impurities was designed and synthesized to catalyze the polymerization of unpurified rac-LA under industrial conditions to obtain high tactical and high molecular weight cyclic polymers. Esters have very important research significance and industrial application prospects.

SUMMARY OF THE INVENTION

One of the objectives of the present invention is to disclose a class of benzimidazole substituted aminophenoxyzinc halides.

The second purpose of the present invention is to disclose the preparation method of a class of benzimidazole substituted aminophenoloxyzinc halides.

The third purpose of the present invention is to disclose the application of a class of benzimidazole substituted aminophenoloxyzinc halides in the polymerization of lactones.

Technical concept of the present invention:

Studies have shown that the synthesis of catalysts with high activity and high tactical selectivity is the key to obtain cyclic polylactide with excellent performance. Compounds containing imidazole rings have an extremely wide range of applications in the field of chemistry. The imine N atom of the imidazole ring is coordinated with the metal center, and another N atom can adjust the steric hindrance effect and electronic effect of the entire catalyst by introducing different groups. On the basis of the central ligand skeleton, changing the relevant substituents on it can adjust the steric hindrance and Lewis acidity of the metal center, thereby regulating the catalytic performance of metal complexes. In the structure of metal complex catalysts, in addition to the steric and electronic factors of the multidentate ligands that affect the catalytic performance of metal complexes, the types of initiating groups connected to the metal center also affect the metal complex catalysts. stability and activity. Compared with metal-silylamine bonds, metal-halogen bonds are relatively inert. Therefore, combined with the regulation of various substituents of multidentate ligands and the introduction of metal-halogen bonds as initiating groups, it is expected to screen out a combination of high activity, high selectivity and A highly efficient catalyst that combines insensitive properties such as water and oxygen. In order to effectively realize the initiation of metal-halogen bonds, epoxycyclohexane is used as a solvent, and thus the cyclization of the polymer chain during the polymerization process is promoted, and finally a high molecular weight cyclic polyester is obtained, which improves its commercial application value.

The benzimidazole substituted aminophenoxyzinc halide (I) provided by the invention is characterized in that, has the following general formula:

In formula (I):

R ¹ -R ² represent hydrogen, C ₁ -C ₂₀ linear, branched or cyclic alkyl, C ₇ -C ₃₀ mono- or polyaryl substituted alkyl, halogen;

R ³ represents C ₁ -C ₂₀ linear, branched or cyclic alkyl group, C ₇ -C ₃₀ mono- or polyaryl substituted alkyl group, C ₆ -C ₁₈ aryl group;

R ⁴ represents a C ₁ -C ₂₀ linear, branched or cyclic alkyl group, a C ₇ -C ₃₀ mono- or polyaryl-substituted alkyl group;

X represents halogen.

More characteristically, in formula (I), R ¹ -R ² are hydrogen, C ₁ -C ₈ linear, branched or cyclic alkyl groups, C ₇ -C ₂₀ mono- or polyaryl-substituted alkanes base, halogen;

R ³ is a C ₁ -C ₈ linear, branched or cyclic alkyl group, a C ₇ -C ₂₀ mono- or polyaryl substituted alkyl group, a C ₆ -C ₁₂ aryl group;

R ⁴ is a C ₁ -C ₈ linear, branched or cyclic alkyl group, a C ₇ -C ₂₀ mono- or polyaryl-substituted alkyl group;

X represents chlorine, bromine or iodine.

In formula (I), R ¹ to R ² are preferably hydrogen, methyl, tert-butyl, cumyl, and trityl; R ³ is preferably methyl, ethyl, isopropyl, n-butyl, tert-butyl base, cyclohexyl, n-hexyl, n-octyl, benzyl, phenethyl; R ⁴ is preferably methyl, ethyl, isopropyl, n-butyl, cyclohexyl, benzyl, phenethyl; X represents chlorine .

Preferred benzimidazole substituted aminophenoxyzinc halides (I) have the following structures:

The above-mentioned preferred benzimidazole-substituted aminophenoloxyzinc halide, its corresponding benzimidazole-substituted aminophenol ligand compound structure is as follows:

Benzimidazole-substituted aminophenoloxyzinc halide (I) of the present invention, preparation method is as follows:

The benzimidazole substituted aminophenol ligand compound represented by the formula (II) is reacted with a hydrogen extraction reagent to obtain the metal salt of the corresponding ligand, and then reacted with the metal raw material compound in an organic medium to generate the benzimidazole substituted aminophenol oxide. base zinc halide, the reaction temperature is -70～80℃, preferably -20～40℃, the reaction time is 8～72 hours, preferably 16-48 hours, and then the benzimidazole of the present invention is collected from the reaction product Substituted aminophenoxyzinc halide (I).

In the above preparation method, the substituents R ¹ to R ⁴ are consistent with the corresponding groups of the benzimidazole-substituted aminophenoxyzinc halide (I) of the present invention;

The hydrogen extraction reagent is a C ₁ -C ₄ alkyl alkali metal compound, sodium hydride, or potassium hydride;

The metal raw material compound has the general formula ZnX ₂ , and X is consistent with the corresponding group of the benzimidazole-substituted aminophenoxyzinc halide (I) of the present invention;

The substance ratio of benzimidazole substituted aminophenol ligand compound (II) to hydrogen extraction reagent is 1:1.5～2.5;

The material ratio of the metal salt of the benzimidazole substituted aminophenol ligand compound to the metal raw material compound is 1:1.0-1.5;

The organic medium is selected from one or both of tetrahydrofuran, ether, toluene, benzene, petroleum ether and n-hexane.

In the above preparation method, it is more characteristic that the hydrogen extraction reagent is sodium hydride, and the metal raw material compound is zinc chloride;

The substance ratio of benzimidazole substituted aminophenol ligand compound (II) to hydrogen extraction reagent is 1:2.0～2.3;

The material ratio of the metal salt of the benzimidazole substituted aminophenol ligand compound to the metal raw material compound is 1:1.0-1.2.

In the above preparation method, the benzimidazole substituted aminophenol ligand compound represented by formula (II) can be synthesized by referring to the method disclosed in patent CN109879810A.

The benzimidazole-substituted aminophenoloxyzinc halide of the present invention is an efficient lactone polymerization catalyst, has high catalytic activity, and can be used for L-lactide, D-lactide, rac-propane Ring-opening polymerization of lactide, meso-lactide, ε-caprolactone, β-butyrolactone, and α-methyltrimethylene cyclocarbonate yields a cyclic polyester.

The benzimidazole substituted aminophenoxyzinc halide of the present invention has extremely strong stability, and can be used for unpurified L-lactide, D-lactide, rac-lactide, meso-propane Ring-opening polymerization of lactide, ε-caprolactone, β-butyrolactone and α-methyl trimethylene cyclocarbonate to obtain high molecular weight cyclic polyester.

When the benzimidazole-substituted aminophenoloxyzinc halide of the present invention is used to catalyze the polymerization of rac-lactide, a cyclic polylactide with high molecular weight and high regularity block structure can be obtained.

Using the benzimidazole-substituted aminophenoloxyzinc halide of the present invention as a catalyst and epoxy cyclohexane as a solvent, the lactide is polymerized to obtain a cyclic polylactide; the material of the catalyst and the monomer during polymerization The ratio of the amount is 1:1～50000, preferably 1:100～20000.

Using the benzimidazole-substituted aminophenoloxyzinc halide of the present invention as a catalyst and epoxy cyclohexane as a solvent, the unpurified lactide is polymerized to obtain a cyclic polylactide; The ratio to the amount of the monomer is 1:1 to 50,000, preferably 1:100 to 20,000.

Using the benzimidazole-substituted aminophenoloxyzinc halide of the present invention as a catalyst, and epoxy cyclohexane as a solvent, ε-caprolactone is polymerized to obtain a cyclic polymer; The ratio of the amount of substances is 1:1 to 50,000, preferably 1:100 to 20,000.

Taking lactide as an example to illustrate the structure of the cyclic polyester synthesized by the present invention, it is shown in formula (III):

Wherein, n is an integer greater than 2.

Taking the benzimidazole-substituted aminophenoloxyzinc halide of the present invention as a catalyst, and taking the polymerization of lactide as an example, the formation of the cyclic polyester is illustrated:

In the polymerization as shown in Examples 8-33, when a high monomer conversion rate is achieved, the molecular weight of the obtained polylactide product is determined by gel permeation chromatography, and the measured number-average molecular weight is far smaller than the theoretical linear structure. The number average molecular weight of the polymer product, and the molecular weight distribution is narrow. For the polymerization shown in Example 34, samples were taken at a low monomer conversion rate of 33%, and the structures of the resulting oligomers were separated by ¹ H NMR and MALDI-TOF mass spectrometry analysis, and no linear polymerization was observed in ¹ H NMR. In the MALDI-TOF mass spectrum, the molecular weight sequence conforms to the cyclic polylactide structure, that is, conforms to the structure shown in formula (III). Further, for the polymerization shown in Example 35, the high monomer conversion rate is 89%. When sampling, the MALDI-TOF mass spectrum was measured on the separated polymer, and its molecular weight sequence still conformed to the cyclic polylactide structure, that is, it had the structure represented by formula (III). As described above, using the benzimidazole substituted aminophenoloxyzinc halide of the present invention as a catalyst, catalyzing the polymerization of lactide to obtain a high molecular weight cyclic polylactide.

Using the benzimidazole substituted aminophenoloxyzinc halide of the present invention as a catalyst to catalyze the polymerization of ε-caprolactone, a polymer with a cyclic structure was also obtained. By analyzing the polymer obtained in Example 23, Its cyclic structure was also confirmed by ¹ H NMR and MALDI-TOF mass spectrometry. It is indicated that the benzimidazole-substituted aminophenoloxyzinc halide of the present invention has universal applicability to different lactone monomers when catalyzing the polymerization of lactones to synthesize cyclic polylactones.

The catalyst provided by the invention is simple and convenient to prepare, has strong tolerance to impurities in the monomer, can catalyze the ring-opening polymerization of a large equivalent of unpurified lactone monomer, and synthesize high molecular weight (M _n =20.2～ 71.7kg/mol) and the cyclic polylactone with high regular structure (P _m =0.84～0.93), which has a wide range of commercial and industrial application prospects. The present invention is further illustrated by examples below, but the present invention is not limited thereto.

Detailed ways

The benzimidazole substituted aminophenol ligand compounds represented by the formula (II) involved in the present invention, such as L ³ H, L ⁴ H, L ¹⁰ H, etc., can be synthesized with reference to the method disclosed in patent CN 109879810 A.

Example 1

Synthesis of Complex Zn3

Under argon protection, NaH (41 mg, 1.68 mmol) was added in portions to a solution of ligand L ³ H (574 mg, 0.85 mmol) in 15 mL of tetrahydrofuran, and the reaction was carried out for 12 hours. Excess NaH was removed by filtration, then anhydrous ZnCl ₂ (120 mg, 0.85 mmol) was added to the reaction solution, and the reaction was continued for 12 h. After subsequent filtration, the solid was sucked dry to give a pale yellow solid, which was recrystallized from dichloromethane and petroleum ether to give Zn3 (311 mg, 47.1%) as a white solid.

¹ H NMR (400 MHz, CDCl ₃ ): δ 7.69-7.61 (m, 1H), 7.48-7.37 (m, 3H), 7.32 (d, J=6.6 Hz, 3H), 7.13 (d, J=7.8 Hz) ,6H),6.96(q,J＝9.3,7.6Hz,9H),6.84(t,J＝7.2Hz,3H),6.66(d,J＝2.3Hz,1H),5.36(d,J＝16.5Hz ,1H),5.12(d,J＝16.9Hz,1H),4.32(d,J＝11.9Hz,1H),4.01(d,J＝16.5Hz,1H),3.76(m,4H×0.5),3.56 (d, J=16.9Hz, 1H), 3.41 (d, J=11.9Hz, 1H), 2.66 (m, 1H), 2.12 (s, 3H), 1.96 (d, J=11.9Hz, 1H), 1.85 (m, 4H×0.5), 1.61 (m, 3H), 1.45 (d, J=13.0Hz, 1H), 1.10–0.79 (m, 5H). Anal.Calcd.for C ₄₈ H ₄₆ ClN ₃ OZn 1.3 _{CH2Cl2 :} C, 66.39; H, 5.92; N, 4.36. Found: C, 66.14; H, 5.72; N, 4.59%.

Example 2

Synthesis of Complex Zn4

Except that the raw material adopts ligand L ⁴ H (522 mg, 0.76 mmol), NaH (36 mg, 1.51 mmol) and ZnCl ₂ (103 mg, 0.76 mmol), the rest of the operation steps are the same as in Example 1, after recrystallization with dichloromethane and petroleum ether White crystals of Zn4 (320 mg, 53.3%) were obtained.

¹ H NMR (400 MHz, CDCl ₃ ): δ 7.67 (d, J=8.0 Hz, 1H), 7.49-7.35 (m, 5H), 7.35-7.29 (m, 1H), 7.24-7.19 (m, 1H) ,7.18–7.08(m,8H),7.03–6.89(m,9H),6.88–6.76(m,5H),6.57(d,J=2.3Hz,1H),5.22(d,J=16.7Hz,1H ),5.03(d,J＝16.7Hz,1H),4.34(d,J＝12.3Hz,1H),4.10(d,J＝14.1Hz,1H),3.83(d,J＝14.1Hz,1H), 3.63(d, J=2.4Hz, 2H), 3.42(d, J=12.3Hz, 1H), 2.07(s, 3H). ¹³ C{ ¹ H} NMR (100MHz, CDCl ₃ ): δ 163.9, 153.2 146.9, 137.7,135.2,134.0,132.7,131.6,131.2,130.9,129.7,129.0,128.7,126.7,126.5,126.3,125.0,124.9,124.8,124.3,121.4,120.9,619,5.6,110.1 47.3, 44.0, 25.7, 20.8. Anal. Calcd. for C ₄₉ H ₄₂ ClN ₃ OZn·0.8CH ₂ Cl ₂ : C, 69.50; H, 5.59; N, 4.52. Found: C, 69.56; H, 6.05; N ,4.36%.

Example 3

Synthesis of Complex Zn7

(1) Synthesis of N-[(1-benzyl-1H-benzimidazol-2-yl)-methyl]isoamylamine

Under the protection of inert gas, isoamylamine (10.7g, 123.0mmol) and anhydrous K ₂ CO ₃ (4.1g, 29.5mmol) were added in a 100mL there-necked flask, and after stirring for 10 minutes, slowly added dropwise from a constant pressure dropping funnel A solution of 1-benzyl-2-chloromethylbenzimidazole (6.3 g, 24.6 mmol) in 25 mL of N,N-dimethylformamide was reacted for 8-9 h. Quench by adding water, extract with ethyl acetate, dry with anhydrous MgSO ₄ , filter, evaporate the solvent under reduced pressure to obtain a yellow viscous liquid, and evaporate the unreacted isoamylamine at 90°C/1mmHg. It is the main product point by TLC analysis, which is directly used in the next reaction, and the purity is about 82% according to the NMR spectrum.

(2) Synthesis of ligand L ⁷ H

N-[(1-benzyl-1H-benzimidazol-2-yl)-methyl]isoamylamine (5.3g, purity 82%, about 17.3mmol), K ₂ CO ₃ ( 2.9 g, 20.8 mmol) and 30 mL of N,N-dimethylformamide, and after stirring for 10 minutes, 2-bromomethyl-4,6-di-tert-butylphenol (7.7 g, 17.3 mmol) was added in portions at room temperature. The reaction was carried out for 12 h, quenched by adding water, extracted with ethyl acetate, washed with saturated aqueous NaCl solution, dried over anhydrous sodium sulfate, evaporated to remove the solvent under reduced pressure, and passed through column chromatography (PE:EA=20:1) to obtain a white solid L ⁷ H (4.3 g, 37.6%).

¹ H NMR (400MHz, CDCl ₃ ): δ9.81(s,1H), 7.78-7.70(m,1H), 7.31-7.26(m,1H), 7.25-7.10(m,20H), 6.95(s, 1H), 6.73(s, 1H), 6.68(d, J=7.7Hz, 2H), 4.83(s, 2H), 3.75(s, 2H), 3.67(s, 2H), 2.58–2.43(m, 2H) ), 2.16(s, 3H), 1.40–1.26(m, J=6.4Hz, 1H), 1.21–1.07(m, 2H), 0.75(d, J=6.5Hz, 6H). ¹³ C{ ¹ H} NMR (100MHz, CDCl ₃ ): δ153.8, 150.3, 146.1, 142.3, 136.0, 135.8, 133.6, 131.2, 130.8, 129.1, 128.9, 127.8, 127.1, 126.1, 125.4, 123.0, 122.3, 122.1, 639. _{58.0,52.2,50.1,46.7,34.8,26.7,22.7,21.0.Anal.Calcd.for C47H47N3O} :C,84.27;H,7.07;N, _6.27.Found :C,84.08;H,7.04 ;N,5.99%.

(3) Synthesis of complex Zn7

Except that the raw material adopts ligand L ⁷ H (533 mg, 0.80 mmol), NaH (38.4 mg, 1.6 mmol) and ZnCl ₂ (109 mg, 0.80 mmol), the rest of the operation steps are the same as in Example 1. Crystallization gave Zn7 (321 mg, 52.2%) as white crystals.

¹ H NMR (400 MHz, CDCl ₃ ): δ 7.64 (d, J=7.6 Hz, 1H), 7.49-7.29 (m, 6H), 7.16 (m, J=16.4, 7.6 Hz, 9H), 7.03-6.88 (m, 8H), 6.82 (t, J=7.3Hz, 3H), 6.68 (s, 1H), 5.32 (d, J=16.6Hz, 1H), 5.14 (d, J=16.6Hz, 1H), 4.27 (d,J＝12.2Hz,1H),4.02(d,J＝16.6Hz,1H),3.76(m,4H×0.7),3.46(d,J＝16.6Hz,1H),3.47(d,J＝ 12.2Hz, 1H), 2.85–2.73(m, 1H), 2.62(d, J=12.7Hz, 1H), 2.12(s, 3H), 1.85(m, 4H×0.7), 1.29(d, J=11.4 Hz, 2H), 1.02(s, 1H), 0.78–0.54(m, 6H). ¹³ C{ ¹ H} NMR (100 MHz, CDCl ₃ ): δ 153.5, 146.9, 138.0, 137.6, 135.1, 133.9, 131.2, 129.6 ,129.1,128.4,126.7,125.4,124.9,124.8,124.3,121.1,120.2,113.8,113.4,110.0,108.3,63.8,47.4,36.5,26.8,25.9,22.4,21.6,20.9,2 Cald.for Cald. _{47H46ClN3OZn · 1.6CH2Cl2 :} C, _64.46 ; H, 5.48; N, 4.64. Found: C, 64.54; H, 5.78; N, 4.60%.

Example 4

Synthesis of Complex Zn10

Except that ligand L ¹⁰ H (384 mg, 0.66 mmol), NaH (32 mg, 1.32 mmol) and ZnCl ₂ (90 mg, 0.66 mmol) were used as raw materials, other operation steps were the same as those in Example 1. Recrystallization from dichloromethane and petroleum ether gave Zn10 as white crystals (203 mg, 42.9%).

¹ H NMR (400 MHz, CDCl ₃ ): δ 7.59 (d, J=7.4 Hz, 1H), 7.39 (m, 2H), 7.28 (m, 2H), 7.23 (m, 1H, ArH), 7.15 (m ,J=7.6Hz,9H),6.96(t,J=7.6Hz,7H),6.82(t,J=7.3Hz,3H),6.70(d,J=2.3Hz,1H),4.52(d,J ＝12.2Hz, 1H), 4.21(d, J＝13.3Hz, 1H), 3.89(d, J＝13.3Hz, 17H), 3.78(d, J＝16.2Hz, 1H), 3.76(m, 4H×0.6 ),3.60(d,J＝16.2Hz,1H),3.53(d,J＝12.3Hz,1H),3.43(s,3H),2.11(s,3H),1.85(m,4H×0.6).Anal _{.Calcd.for C43H38ClN3OZn · 0.8CH2Cl2 :} C, 69.50; H, 5.59; N, 4.52. Found: C, 69.56; H, 6.05; N, 4.36%.

Example 5

Synthesis of Complex Zn12

(1) Synthesis of N-[(1-methyl-1H-benzimidazol-2-yl)-methyl]n-octylamine

Under the protection of inert gas, n-octylamine (23.8g, 184.6mmol) and anhydrous K ₂ CO ₃ (6.1g, 44.3mmol) were added in a 100mL there-necked flask, and after stirring for 10 minutes, slowly added dropwise from a constant pressure dropping funnel A solution of 1-methyl-2-chloromethylbenzimidazole (6.7g, 36.9mmol) in 25mL of N,N-dimethylformamide was reacted for 8-9h. Quench by adding water, extract with ethyl acetate, dry with anhydrous MgSO ₄ , filter, evaporate the solvent under reduced pressure to obtain a yellow viscous liquid, and evaporate unreacted n-octylamine at 90°C/1mmHg. It is the main product point by TLC analysis, which is directly used in the next reaction, and the purity is about 82% according to the NMR spectrum.

(2) Synthesis of ligand L ¹² H

N-[(1-methyl-1H-benzimidazol-2-yl)-methyl] n-octylamine (10.2g, purity 82%, about 39.4mmol), K ₂ CO ₃ ( 6.5g, 47.2mmol) and 30mL N,N-dimethylformamide, after stirring for 10 minutes, 2-bromomethyl-4,6-di-tert-butylphenol (17.4g, 39.4mmol) was added in batches, room temperature The reaction was carried out for 12 h, quenched by adding water, extracted with ethyl acetate, washed with saturated aqueous NaCl solution, dried over anhydrous sodium sulfate, evaporated to remove the solvent under reduced pressure, and subjected to column chromatography (PE:EA=10:1) to obtain a white solid L ¹² H (10.27 g, 48.9%).

¹ H NMR (400 MHz, CDCl ₃ ): δ 9.82 (s, 1H), 7.70 (d, J=7.7 Hz, 1H), 7.29 (d, J=7.0 Hz, 1H), 7.24 (d, J=4.4 Hz, 1H), 7.21(m, 13H), 7.17–7.11(m, 3H), 6.92(s, 1H), 6.76(s, 1H), 3.76(s, 2H), 3.75(s, 2H), 3.14 (s, 3H), 2.48–2.36 (m, 2H), 2.15 (s, 3H), 1.45–1.31 (m, 2H), 1.26 (m, 2H), 1.22–1.12 (m, 6H), 1.08 (m , 2H), 0.87 (t, J=7.0Hz, 3H). ¹³ C{ ¹ H} NMR (100 MHz, CDCl ₃ ): δ153.7, 150.2, 146.1, 142.2, 136.1, 133.6, 131.2, 129.0, 127.2, 127.1, 125.4,122.8,122.2,121.9,119.7,109.4,63.2,58.5,54.0,50.5,31.9,29.9,29.4,29.3,27.4,26.0,22.7,21.0,14.2.Anal.Calcd.for C ₄₄ H ₄₉ N ₃ O : C, 83.11; H, 7.77; N, 6.61. Found: C, 83.14; H, 7.80; N, 6.50%.

(3) Synthesis of complex Zn12

Except that the raw material adopts ligand L ¹² H (602 mg, 0.95 mmol), NaH (46 mg, 1.9 mmol) and ZnCl ₂ (129 mg, 0.95 mmol), the rest of the operation steps are the same as in Example 1, and recrystallized from toluene and petroleum ether to obtain white Crystalline Zn12 (310 mg, 44.4%).

¹ H NMR (400 MHz, CDCl ₃ ): δ 7.59 (dt, J=7.2, 3.5 Hz, 1H), 7.41 (dt, J=7.1, 3.6 Hz, 2H), 7.37 (m, 1H), 7.16-7.09 (m, 6H), 6.99–6.88 (m, 7H), 6.81 (t, J=7.3Hz, 3H), 6.75 (d, J=2.4Hz, 1H), 4.36 (d, J=12.1Hz, 1H) ,4.10(d,J＝16.6Hz,1H),3.70(d,J＝16.6Hz,1H),3.65(s,3H),3.45(d,J＝12.1Hz,1H),2.92(td,J＝ 12.4, 4.4Hz, 1H), 2.73(td, J=12.4, 4.5Hz, 1H), 2.10(s, 3H), 1.62(m, 1H), 1.36(m, 1H), 1.17(m, 10H), 0.82 (t, J=6.9Hz, 3H). ¹³ C{ ¹ H} NMR (100 MHz, CDCl ₃ ): δ 164.0, 153.5, 146.9, 137.5, 137.5, 135.3, 133.0, 131.3, 126.6, 124.8, 124.5, 124.0, 121.6,121.3,119.8,109.9,63.7,61.3,59.5,51.7,47.7,31.8,30.3,29.3,27.5,25.6,22.7,20.8,14.2.Anal.Calcd.for C ₄₄ H ₄₈ ClN ₃ OZn 0.4C ₇ H ₈ : C, 73.19; H, 6.73; N, 5.31. Found: C, 73.48; H, 6.36; N, 4.90%.

Example 6

Synthesis of Complex Zn13

(1) Synthesis of N-[(1-methyl-1H-benzimidazol-2-yl)-methyl]isoamylamine

Under the protection of inert gas, isoamylamine (18.0g, 206.5mmol) and anhydrous K ₂ CO ₃ (6.85g, 49.6mmol) were added in a 100mL there-necked flask, and after stirring for 10 minutes, slowly added dropwise from a constant pressure dropping funnel A solution of 1-methyl-2-chloromethylbenzimidazole (7.5g, 41.3mmol) in 25mL of N,N-dimethylformamide was reacted for 8-9h. Quench by adding water, extract with ethyl acetate, dry with anhydrous MgSO ₄ , filter, evaporate the solvent under reduced pressure to obtain a yellow viscous liquid, and evaporate the unreacted isoamylamine at 90°C/1mmHg. It is the main product point by TLC analysis, which is directly used in the next reaction, and the purity is about 82% according to the NMR spectrum.

(2) Synthesis of ligand L ¹³ H

N-[(1-methyl-1H-benzimidazol-2-yl)-methyl]isoamylamine (2.3g, purity 82%, about 10.0mmol), K ₂ CO ₃ ( 1.65g, 12.0mmol) and 30mL N,N-dimethylformamide, after stirring for 10 minutes, 2-bromomethyl-4,6-di-tert-butylphenol (4.43g, 10.0mmol) was added in portions, The reaction was carried out at room temperature for 12 h, quenched with water, extracted with ethyl acetate, washed with saturated aqueous NaCl solution, dried over anhydrous sodium sulfate, evaporated to remove the solvent under reduced pressure, and subjected to column chromatography (PE:EA=10:1) to obtain a white solid ^L13 H (10.27 g, 48.9%).

¹ H NMR (400 MHz, CDCl ₃ ): δ 9.82 (s, 1H), 7.69 (d, J=7.8 Hz, 1H), 7.29 (d, J=7.2 Hz, 1H), 7.25-7.10 (m, 17H ),6.92(d,J=2.4Hz,1H),6.76(d,J=2.4Hz,1H),3.75(s,2H),3.74(s,2H),3.12(s,3H),2.54–2.37 (m, 2H), 2.15(s, 3H), 1.42–1.34 (m, 1H), 1.34–1.25 (m, 2H), 0.77 (d, J=6.4Hz, 6H). ¹³ C{ ¹ H}NMR (100MHz,CDCl ₃ ):δ153.7,150.1,146.0,142.1,136.1,133.5,131.21,130.93,128.94,127.15,127.08,125.44,122.75,122.13,121.84,119.66,109.41,63.2,58.4,52.3,50.4,34.5 , 30.0, 26.6, 22.7, 21.0. Anal.Calcd. for C ₄₁ H ₄₃ N ₃ O: C, 82.93; H, 7.30; N, 7.08. Found: C, 82.92; H, 7.41; N, 6.93%.

(3) Synthesis of complex Zn13

Except that the raw material adopts ligand L ¹³ H (441 mg, 0.74 mmol), NaH (35.5 mg, 1.48 mmol) and ZnCl ₂ (101 mg, 0.74 mmol), the rest of the operation steps are the same as those in Example 1, after heavy mixing of dichloromethane and petroleum ether Crystallization gave Zn13 as white crystals (215 mg, 45.8%).

¹ H NMR (400 MHz, CDCl ₃ ): δ 7.59 (m, 1H), 7.42 (m, 2H), 7.37 (m, 1H), 7.14 (m, 6H), 7.00-6.89 (m, 7H), 6.82 (t,J=7.3Hz,3H),6.75(d,J=2.3Hz,1H),4.35(d,J=12.0Hz,1H),4.09(d,J=16.6Hz,1H),3.76(m ,4H×0.5),3.64(d,J=16.6Hz,2H),3.61(s,3H),3.46(d,J=12.0Hz,1H),3.02–2.88(m,1H),2.78(m 1H) ), 2.10(s, 3H), 1.85(m, 4H×0.5), 1.48(td, J=12.7, 5.7Hz, 2H), 1.35–1.20(m, 1H), 0.90–0.71(m, 6H). ¹³ C{ ¹ H} NMR (100 MHz, CDCl ₃ ): δ 163.9, 153.2, 146.9, 137.6, 135.3, 131.2, 129.1, 128.3, 126.7, 126.6, 124.8, 124.2, 121.3, 121.1, 119.9, 109.8, 68.3, 63 62.8, 33.8, 30.3, 27.0, 25.8, 22.7, 20.8. Anal.Calcd.for C ₄₃ H ₃₈ ClN ₃ OZn·1.6CH ₂ Cl ₂ : C, 67.31; H, 5.11; N, 5.38. Found: C, 67.29 ; H, 5.17; N, 5.48%.

Example 7

Synthesis of Complex Zn15

(1) Synthesis of N-[(1-isopropyl-1H-benzimidazol-2-yl)-methyl]cyclohexylamine

Under the protection of inert gas, cyclohexylamine (19.9g, 200.5mmol) and anhydrous K ₂ CO ₃ (6.7g, 48.1mmol) were added in a 100mL there-necked flask, and after stirring for 10 minutes, slowly added dropwise from a constant pressure dropping funnel 1-Isopropyl-2-chloromethylbenzimidazole (8.4g, 40.1mmol) in 25mL N,N-dimethylformamide solution, react for 8-9h. Add water to quench, extract with ethyl acetate, dry with anhydrous MgSO ₄ , filter, evaporate the solvent under reduced pressure to obtain a yellow viscous liquid, and evaporate unreacted cyclohexylamine at 90°C/1mmHg. It is the main product point by TLC analysis, which is directly used in the next reaction, and the purity is about 82% according to the NMR spectrum.

(2) Synthesis of ligand L ¹⁵ H

N-[(1-isopropyl-1H-benzimidazol-2-yl)-methyl]cyclohexylamine (3.7g, purity 82%, about 13.7mmol), K ₂ CO ₃ was added to a 100 mL single-necked bottle (2.3g, 16.5mmol) and 30mL N,N-dimethylformamide, after stirring for 10 minutes, 2-bromomethyl-4,6-di-tert-butylphenol (6.1g, 13.7mmol) was added in portions, The reaction was carried out at room temperature for 12 h, quenched by adding water, extracted with ethyl acetate, washed with saturated aqueous NaCl solution, dried over anhydrous sodium sulfate, evaporated to remove the solvent under reduced pressure, and recrystallized from dichloromethane and petroleum ether to obtain a white solid L ¹⁵ H (3.6 g , 42.9%).

¹ H NMR (400 MHz, CDCl ₃ ): δ 9.82 (s, 1H), 7.70 (d, J=7.7 Hz, 1H), 7.29 (d, J=7.0 Hz, 1H), 7.24 (d, J=4.4 Hz, 1H), 7.21(m, 13H), 7.17–7.11(m, 3H), 6.92(s, 1H), 6.76(s, 1H), 3.76(s, 2H), 3.75(s, 2H), 3.14 (s, 3H), 2.48–2.36 (m, 2H), 2.15 (s, 3H), 1.45–1.31 (m, 2H), 1.26 (m, 2H), 1.22–1.12 (m, 6H), 1.08 (m , 2H), 0.87 (t, J=7.0Hz, 3H). ¹³ C{ ¹ H}NMR (100MHz, CDCl ₃ ): δ153.9, 149.9, 146.1, 143.0, 133.9, 133.5, 131.2, 130.4, 128.6, 126.8, _{H _ _} , 7.77; N, 6.61. Found: C, 83.14; H, 7.80; N, 6.50%.

(3) Synthesis of complex Zn15

Except that the raw material adopts ligand L ¹⁵ H (531 mg, 0.84 mmol), NaH (40 mg, 1.68 mmol) and ZnCl ₂ (115 mg, 0.84 mmol), the rest of the operation steps are the same as in Example 1, after recrystallization with dichloromethane and petroleum ether White crystals of Zn15 were obtained (284 mg, 45.9%).

¹ H NMR (400 MHz, CDCl ₃ ): δ 7.57-7.49 (m, 1H), 7.48-7.39 (m, 1H), 7.33-7.25 (m, 2H), 7.11-7.03 (m, 6H), 6.96- 6.83 (m, 7H), 6.81–6.72 (m, 3H), 6.64 (d, J=2.3Hz, 1H), 4.49 (hept, J=6.9Hz, 1H), 4.26 (d, J=12.1Hz, 1H) ),3.95(d,J＝10.8Hz,1H),3.70(d,J＝10.8Hz,1H),3.45(d,J＝12.1Hz,1H),2.72(m,1H),2.10(m,1H ),2.05(s,3H),1.68(q,J＝11.5,9.4Hz,3H),1.59(d,J＝6.9Hz,3H),1.53(d,J＝6.9Hz,3H),1.32–0.88 (m, 6H). ¹³ C{ ¹ H} NMR (100 MHz, CDCl ₃ ): δ 163.8, 152.78, 146.9, 138.3, 137.5, 133.2, 132.7, 131.3, 126.6, 124.7, 124.2, 123.8, 121.1, 121.0, 120.3, 112.0, 68.1, 66.3, 63.8, 58.3, 49.0, 46.3, 30.3, 27.7, 25.7, 21.6, 20.9. Anal.Calcd.for C ₄₄ H ₄₆ ClN ₃ OZn 0.4CH ₂ Cl ₂ : C, 69.55; H, 6.36 ;N,5.52.Found:C,69.47;H,6.15;N,5.47%.

Example 8

Under argon protection, unpurified racemic lactide (0.144 g, 1.00 mmol) was added to the polymerization flask, and 0.5 mL of the epoxy cyclohexane solution of catalyst Zn3 was measured and added to the polymerization flask. [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200. The reaction temperature was controlled at 80±1°C, and after 84 minutes of reaction, petroleum ether was added to terminate the reaction. The solvent was removed by suction, the residue was dissolved in dichloromethane, methanol was added to precipitate the polymer, and then the polymer was washed with methanol and dried in vacuo for 24 h. Conversion: 90%, _Mn = 2.0×10 ⁴ g/mol, molecular weight distribution PDI = 1.22, isotacticity P _m =0.68.

Example 9

Except that the reaction temperature was lowered to 25±1°C, other operations were the same as in Example 8, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1: 200, after 4 days of reaction, conversion rate: 92%, _Mn = 2.2×10 ⁴ g/mol, molecular weight distribution PDI = 1.10, isotacticity P _m = 0.83.

Example 10

Except that the catalyst was replaced with Zn4, other operations were the same as in Example 8, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, in the reaction At a temperature of 80±1° C., after 30 minutes of reaction, conversion rate: 90%, _Mn = 2.1×10 ⁴ g/mol, molecular weight distribution PDI = 1.22, isotacticity P _m = 0.65.

Example 11

Except that the catalyst was replaced with Zn4, other operations were the same as in Example 9, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, reaction 3 After one day, conversion: 93%, _Mn = 2.3 x ¹⁰⁴ g/mol, molecular weight distribution PDI = 1.15, isotacticity _Pm = 0.79.

Example 12

Except that the catalyst was changed to Zn7, other operations were the same as in Example 8, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, and the reaction At a temperature of 80±1° C., after 35 minutes of reaction, conversion rate: 93%, _Mn = 2.3×10 ⁴ g/mol, molecular weight distribution PDI = 1.24, isotacticity P _m = 0.69.

Example 13

Except that the catalyst was changed to Zn7, other operations were the same as in Example 9, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, and the reaction At a temperature of 25±1° C., after 3 days of reaction, conversion rate: 84%, _Mn = 2.0×10 ⁴ g/mol, molecular weight distribution PDI = 1.12, isotacticity P _m = 0.84.

Example 14

Except that the catalyst was replaced with Zn10, other operations were the same as in Example 8, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, in the reaction At a temperature of 80±1° C., after 32 minutes of reaction, conversion rate: 93%, _Mn = 2.1×10 ⁴ g/mol, molecular weight distribution PDI = 1.24, isotacticity P _m = 0.65.

Example 15

Except that the catalyst is replaced with Zn10, other operations are the same as in Example 9, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, and the reaction At a temperature of 25±1° C., after 3 days of reaction, conversion rate: 91%, _Mn = 2.0×10 ⁴ g/mol, molecular weight distribution PDI = 1.12, isotacticity P _m = 0.79.

Example 16

Except that the catalyst was replaced with Zn12, other operations were the same as in Example 8, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200. At a reaction temperature of 80±1° C., after 40 minutes of reaction, conversion: 89%, _Mn = 2.2×10 ⁴ g/mol, molecular weight distribution PDI = 1.18, isotacticity P _m = 0.72.

Example 17

Except that the catalyst was replaced with Zn12, other operations were the same as in Example 9, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, in the reaction At a temperature of 25±1° C., after 3 days of reaction, conversion rate: 93%, _Mn = 2.4×10 ⁴ g/mol, molecular weight distribution PDI = 1.10, isotacticity P _m = 0.87.

Example 18

Under argon protection, unpurified racemic lactide (0.144 g, 1.00 mmol) was added to the polymerization flask, and 0.5 mL of the epoxy cyclohexane solution of catalyst Zn12 was measured and added to the polymerization flask. [rac-LA] ₀ =2.0M, [Zn] ₀ =0.03M, [Zn] ₀ :[rac-LA] ₀ =1:60. The reaction temperature was controlled to -45±1°C, and after 14 days of reaction, petroleum ether was added to terminate the reaction. The solvent was removed by suction, the residue was dissolved in dichloromethane, methanol was added to precipitate the polymer, and then the polymer was washed with methanol and dried in vacuo for 24 h. Conversion: 96%, _Mn = 7.6 x 10 ³ g/mol, molecular weight distribution PDI = 1.16, isotacticity P _m =0.93.

Example 19

Except that the catalyst was replaced with Zn13, other operations were the same as in Example 8, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200. At a reaction temperature of 80±1° C., after 38 minutes of reaction, conversion: 94%, _Mn = 2.5×10 ⁴ g/mol, molecular weight distribution PDI = 1.23, isotacticity P _m = 0.69.

Example 20

Except that the catalyst was replaced with Zn13, other operations were the same as in Example 9, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, in the reaction At a temperature of 25±1° C., after 3 days of reaction, conversion rate: 90%, _Mn = 2.1×10 ⁴ g/mol, molecular weight distribution PDI = 1.13, isotacticity P _m = 0.83.

Example 21

Except that the catalyst was replaced with Zn15, other operations were the same as in Example 8, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200. At a reaction temperature of 80±1°C, after 107 minutes of reaction, conversion: 93%, _Mn =2.4×10 ⁴ g/mol, molecular weight distribution PDI=1.22, isotacticity _Pm =0.68.

Example 22

Except that the catalyst was replaced with Zn15, other operations were the same as in Example 9, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, in the reaction At a temperature of 25±1° C., after 4 days of reaction, conversion rate: 91%, _Mn = 2.4×10 ⁴ g/mol, molecular weight distribution PDI = 1.14, isotacticity P _m = 0.82.

Example 23

Except that the catalyst was replaced by Zn4 and the monomer was replaced by unpurified ε-caprolactone, other operations were the same as in Example 8, [ε-CL] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[ ε-CL] ₀ = 1:200. At a reaction temperature of 80±1° C., after 3.1 hours of reaction, conversion rate: 72%, _Mn = 1.5×10 ⁴ g/mol, molecular weight distribution PDI = 1.41.

Example 24

Except that the catalyst was changed to Zn4, [Zn] ₀ =0.004M, [Zn] ₀ :[rac-LA] ₀ =1:500, other operations were the same as in Example 8. LA] ₀ =2.0M, after 42 minutes of reaction, conversion: 84%, M _n =2.0×10 ⁴ g/mol, molecular weight distribution PDI=1.23.

Example 25

Except that the catalyst was changed to Zn4, [Zn] ₀ =0.002M, [Zn] ₀ :[rac-LA] ₀ =1:1000, other operations were the same as in Example 8. LA] ₀ =2.0M, after 100 minutes of reaction, conversion rate: 87%, M _n =2.1×10 ⁴ g/mol, molecular weight distribution PDI=1.22.

Example 26

Except that the catalyst was changed to Zn4, [Zn] ₀ =0.0005M, [Zn] ₀ :[rac-LA] ₀ =1:4000, other operations were the same as in Example 8. LA] ₀ =2.0M, after 8 hours of reaction, conversion rate: 87%, _Mn =2.1×10 ⁴ g/mol, molecular weight distribution PDI=1.21.

Example 27

Except that the catalyst was changed to Zn4, [Zn] ₀ =0.0002M, [Zn] ₀ :[rac-LA] ₀ =1:10000, other operations were the same as in Example 8. LA] ₀ =2.0M, after 22 hours of reaction, conversion rate: 89%, M _n =2.0×10 ⁴ g/mol, molecular weight distribution PDI=1.22.

Example 28

Except that the catalyst was replaced with Zn4, [Zn] ₀ =0.0001M, [Zn] ₀ :[rac-LA] ₀ =1:20000, other operations were the same as in Example 8. LA] ₀ =2.0M, after 50 hours of reaction, conversion rate: 88%, _Mn =2.1×10 ⁴ g/mol, molecular weight distribution PDI=1.25.

Example 29

Except the catalyst is replaced with Zn4, the lactide dosage is increased to 0.36g, [rac-LA] ₀ =5.0M, [Zn] ₀ =0.01M, other operations are the same as in Example 8, [Zn] ₀ : [rac-LA ] ₀ =1:1000, at a reaction temperature of 80±1° C., after 50 minutes of reaction, conversion rate: 97%, _Mn = 3.74×10 ⁴ g/mol, molecular weight distribution PDI = 1.52.

Example 30

Except that the catalyst is replaced with Zn4, the lactide dosage is increased to 0.54g, [rac-LA] ₀ =7.5M, [Zn] ₀ =0.015M, other operations are the same as in Example 8, [Zn] ₀ : [rac-LA ] ₀ =1:1000, at a reaction temperature of 80±1° C., after 37 minutes of reaction, conversion rate: 95%, M _n =4.19×10 ⁴ g/mol, molecular weight distribution PDI=1.42.

Example 31

Except that the catalyst is replaced with Zn4, the lactide dosage is increased to 0.72g, [rac-LA] ₀ =10.0M, [Zn] ₀ =0.02M, other operations are the same as in Example 8, [Zn] ₀ : [rac-LA ] ₀ =1:1000, at a reaction temperature of 80±1° C., after 23 minutes of reaction, conversion rate: 87%, M _n =4.71×10 ⁴ g/mol, molecular weight distribution PDI=1.38.

Example 32

Except that the catalyst is replaced with Zn4, the lactide dosage is increased to 1.008g, [rac-LA] ₀ =14.0M, [Zn] ₀ =0.028M, other operations are the same as in Example 8, [Zn] ₀ : [rac-LA ] ₀ =1:1000, at a reaction temperature of 80±1° C., after 20 minutes of reaction, conversion rate: 97%, M _n =5.8×10 ⁴ g/mol, molecular weight distribution PDI=1.60.

Example 33

Except that the catalyst was changed to Zn4, the monomer was changed to L-lactide, and the amount was increased to 1.008g, [L-LA] ₀ =14.0M, [Zn] ₀ =0.028M, other operations were the same as in Example 8, [ Zn] ₀ : [L-LA] ₀ =1:1000, at a reaction temperature of 80±1° C., after 14 minutes of reaction, conversion rate: 92%, _Mn = 7.17×10 ⁴ g/mol, molecular weight distribution PDI= 1.58.

Example 34

Under argon protection, unpurified racemic lactide (0.144 g, 1.00 mmol) was added to the polymerization bottle, and 0.5 mL of the epoxy cyclohexane solution of catalyst Zn4 was measured and added to the polymerization bottle. [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200. The reaction temperature was controlled at 80±1°C, and after 8 minutes of reaction, petroleum ether was added to terminate the reaction. The solvent was removed by suction, the residue was dissolved in dichloromethane, methanol was added to precipitate the polymer, and then the polymer was washed with methanol and dried in vacuo for 24 h. Conversion: 33%, _Mn =7.3×10 ³ g/mol, molecular weight distribution PDI=1.14.

Example 35

Under argon protection, unpurified racemic lactide (0.144 g, 1.00 mmol) was added to the polymerization bottle, and 0.5 mL of the epoxy cyclohexane solution of catalyst Zn4 was measured and added to the polymerization bottle. [rac-LA] ₀ =2.0M, [Zn] ₀ =0.1M, [Zn] ₀ :[rac-LA] ₀ =1:20. The reaction temperature was controlled at 80±1°C, and after 7 minutes of reaction, petroleum ether was added to terminate the reaction. The solvent was removed by suction, the residue was dissolved in dichloromethane, methanol was added to precipitate the polymer, and then the polymer was washed with methanol and dried in vacuo for 24 h. Conversion: 89%, _Mn =2.2×10 ³ g/mol, molecular weight distribution PDI=1.19.

Example 36

Under argon protection, the purified racemic lactide (0.144 g, 1.00 mmol) was added to the polymerization bottle, and 0.5 mL of the epoxy cyclohexane solution of the catalyst Zn3 was measured and added to the polymerization bottle. [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200. The reaction temperature was controlled at 80±1°C, and after 80 minutes of reaction, petroleum ether was added to terminate the reaction. The solvent was removed by suction, the residue was dissolved in dichloromethane, methanol was added to precipitate the polymer, and then the polymer was washed with methanol and dried in vacuo for 24 h. Conversion: 85%, _Mn =2.0×10 ⁴ g/mol, molecular weight distribution PDI=1.16.

Example 37

Except that the catalyst was changed to Zn4, other operations were the same as in Example 36, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, in the reaction At a temperature of 80±1° C., after 27 minutes of reaction, conversion rate: 91%, _Mn = 2.3×10 ⁴ g/mol, molecular weight distribution PDI = 1.17.

Example 38

Except that the catalyst is replaced with Zn7, other operations are the same as in Example 36, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, and the reaction At a temperature of 80±1° C., after 33 minutes of reaction, conversion rate: 90%, _Mn = 2.4×10 ⁴ g/mol, molecular weight distribution PDI = 1.17.

Example 39

Except that the catalyst was replaced with Zn10, other operations were the same as in Example 36, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, in the reaction At a temperature of 80±1° C., after 27 minutes of reaction, conversion rate: 93%, M _n =2.5×10 ⁴ g/mol, molecular weight distribution PDI=1.16.

Example 40

Except that the catalyst was replaced with Zn12, other operations were the same as in Example 36, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, in the reaction At a temperature of 80±1° C., after 35 minutes of reaction, conversion rate: 85%, _Mn = 2.2×10 ⁴ g/mol, molecular weight distribution PDI = 1.15.

Example 41

Except that the catalyst was replaced with Zn13, other operations were the same as in Example 36, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, and the reaction was carried out as in Example 36. At a temperature of 80±1° C., after 34 minutes of reaction, conversion rate: 89%, M _n =2.3×10 ⁴ g/mol, molecular weight distribution PDI=1.15.

Example 42

Except that the catalyst was replaced with Zn15, other operations were the same as in Example 36, [rac-LA] ₀ =2.0M, [Zn] ₀ =0.01M, [Zn] ₀ :[rac-LA] ₀ =1:200, in the reaction At a temperature of 80±1° C., after 105 minutes of reaction, conversion rate: 95%, _Mn = 2.6×10 ⁴ g/mol, molecular weight distribution PDI = 1.18.

Example 43

Under argon protection, the purified racemic lactide (0.144 g, 1.00 mmol) was added to the polymerization flask, and 0.5 mL of the epoxy cyclohexane solution of catalyst Zn4 was measured and added to the polymerization flask. [rac-LA] ₀ =2.0M, [Zn] ₀ =0.002M, [Zn] ₀ :[rac-LA] ₀ =1:1000. The reaction temperature was controlled at 80±1°C, and after 80 minutes of reaction, petroleum ether was added to terminate the reaction. The solvent was removed by suction, the residue was dissolved in dichloromethane, methanol was added to precipitate the polymer, and then the polymer was washed with methanol and dried in vacuo for 24 h. Conversion: 83%, _Mn =2.5×10 ⁴ g/mol, molecular weight distribution PDI=1.21.

Claims (10)

1. a benzimidazole substituted aminophenoxy zinc halide (I), is characterized in that, has following general formula:

In formula (I): R ¹ -R ² represent hydrogen, C ₁ -C ₂₀ linear, branched or cyclic alkyl, C ₇ -C ₃₀ mono- or polyaryl substituted alkyl, halogen; R ³ represents C ₁ -C ₂₀ linear, branched or cyclic alkyl group, C ₇ -C ₃₀ mono- or polyaryl substituted alkyl group, C ₆ -C ₁₈ aryl group; R ⁴ represents a C ₁ -C ₂₀ linear, branched or cyclic alkyl group, a C ₇ -C ₃₀ mono- or polyaryl-substituted alkyl group; X represents halogen. 2. The benzimidazole-substituted aminophenoloxyzinc halide (I) according to claim 1, wherein R ¹ to R ² are hydrogen, and C ₁ to C ₈ have a linear, branched or cyclic structure Alkyl, C ₇ -C ₂₀ mono- or polyaryl-substituted alkyl, halogen; R ³ is C ₁ -C ₈ straight-chain, branched or cyclic alkyl, C ₇ -C ₂₀ mono- or Polyaryl-substituted alkyl group, C ₆ -C ₁₂ aryl group; R ⁴ is C ₁ -C ₈ straight-chain, branched-chain or cyclic alkyl group, C ₇ -C ₂₀ mono- or polyaryl-substituted alkane group; X is chlorine, bromine or iodine. 3. The benzimidazole-substituted aminophenoloxyzinc halide (I) according to claim 1, wherein R ¹ to R ² are hydrogen, methyl, tert-butyl, cumyl, trityl ; R ³ is methyl, ethyl, isopropyl, n-butyl, tert-butyl, cyclohexyl, n-hexyl, n-octyl, benzyl, phenethyl; R ⁴ is methyl, ethyl, isopropyl base, n-butyl, cyclohexyl, benzyl, phenethyl; X is chlorine. 4. the preparation method of the benzimidazole substituted aminophenoxyzinc halide (I) described in any one of claim 1～3, comprises the steps:

The benzimidazole substituted aminophenol ligand compound represented by the formula (II) is reacted with a hydrogen extraction reagent to obtain the metal salt of the corresponding ligand, and then reacted with the metal raw material compound in an organic medium to generate the benzimidazole substituted aminophenol oxide. base zinc halide, the reaction temperature is -70～80 ℃, preferably -20～40 ℃, the reaction time is 8～72 hours, preferably 16-48 hours, then collect the benzimidazole substituted aminophenoloxyzinc from the reaction product Halide (I); In the above preparation method, the substituents R ¹ to R ⁴ are consistent with the corresponding groups satisfying the benzimidazole-substituted aminophenoxyzinc halide (I) according to any one of claims 1 to 3; The hydrogen extraction reagent is a C ₁ -C ₄ alkyl alkali metal compound, sodium hydride, or potassium hydride; The metal raw material compound has the general formula ZnX ₂ , and X is consistent with the corresponding group satisfying the benzimidazole-substituted aminophenoxyzinc halide (I) according to any one of claims 1 to 3; The ratio of the amount of the benzimidazole substituted aminophenol ligand compound (II) to the substance of the hydrogen extraction reagent is 1:1.5 to 2.5; the ratio of the metal salt of the benzimidazole substituted aminophenol ligand compound to the substance of the metal raw material compound The ratio of quantity is 1:1.0～1.5; The organic medium is selected from one or both of tetrahydrofuran, ether, toluene, benzene, petroleum ether and n-hexane. 5. method according to claim 4, is characterized in that, hydrogen extraction reagent is sodium hydride; Metal raw material compound is zinc chloride; The ratio of the amount of substance of benzimidazole substituted aminophenols ligand compound and hydrogen extraction reagent It is 1:2.0～2.3; the material ratio of the metal salt of the benzimidazole substituted aminophenol ligand compound to the metal raw material compound is 1:1.0～1.2. 6 . The application of the benzimidazole substituted aminophenoloxyzinc halide according to any one of claims 1 to 3 , characterized in that it is used for ring-opening polymerization of lactones to obtain cyclic polyesters. 7 . 7. application according to claim 6 is characterized in that, lactone is selected from L-lactide, D-lactide, rac-lactide, meso-lactide, ε-caprolactone, β-lactide -Butyrolactone, α-methyltrimethylene cyclocarbonate, and can be processed without purification. 8. The application according to claim 6, wherein the benzimidazole-substituted aminophenoloxyzinc halide according to any one of claims 1 to 3 is used as a catalyst, and epoxy cyclohexane is used as a solvent, For ring-opening polymerization of lactide, the substance ratio of the catalyst to the monomer is 1:1 to 50,000, preferably 1:100 to 20,000. 9. The application according to claim 6, characterized in that, using the benzimidazole-substituted aminophenoloxyzinc halide according to any one of claims 1 to 3 as a catalyst, and using epoxycyclohexane as a solvent, The ratio of the amount of the catalyst to the monomer is 1:1 to 50,000, and preferably 1:100 to 20,000 for ring-opening polymerization of lactide that has not been purified. 10. The application according to claim 6, wherein the benzimidazole-substituted aminophenoloxyzinc halide according to any one of claims 1 to 3 is used as a catalyst, and epoxycyclohexane is used as a solvent, For ring-opening polymerization of ε-caprolactone, the ratio of the amount of the catalyst to the monomer is 1:1 to 50,000, preferably 1:100 to 20,000.