Bridged double-center carbene catalyst ligand as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of organic synthesis and carbene catalysts, and particularly relates to a bridged double-center carbene catalyst ligand as well as a preparation method and application thereof. The structure of the bridged double-center carbene catalyst ligand is as shown in a formula I: # imgabs0 #, in the formula I, R1, R3, R4, R5, R6, R7, R8, R9 and R10 are respectively and independently selected from any one of H, i-Pr, CH3, Cl, F and NC; n is equal to 1-9; n is selected from any one of Cl and Br. Compared with a carbene catalyst ligand used in the past, the bridged double-center carbene catalyst ligand provided by the invention has double active centers, so that the double-center carbene catalyst ligand can be used for preparing the double-active-center carbene catalyst ligand, and the double-active-center carbene catalyst ligand can be used for preparing the double-active-center carbene catalyst ligand; and by carrying out ligand exchange with a carbene catalyst precursor with a single active center, the active center can be aggregated, so that the high-activity carbene catalyst with double centers is obtained, and higher reaction activity and atom economy are achieved.

Description

Technical Field

[0001] This application belongs to the technical field of organic synthesis and carbene catalysts, and particularly relates to a bridged bimetallic carbene catalyst ligand, a preparation method thereof, and an application thereof. Background Art

[0002] Olefin metathesis reaction is a reaction in which, under the action of metal carbene compounds, the unsaturated carbon-carbon bonds rearrange to reconstruct the carbon chain skeleton. Therefore, the emergence of olefin metathesis reaction provides a new idea for the design and synthesis of unsaturated molecules, and has now been widely used as a powerful and effective synthesis method in various organic synthesis reactions for constructing carbon-carbon bonds. In addition, since the olefin metathesis reaction only requires a catalytic amount of metal carbene and usually the only by-product of the reaction is a volatile hydrocarbon such as ethylene, it fully conforms to the concept of "green chemistry". With the development of olefin metathesis reaction, several important reaction types have gradually become well-known to people, such as Figure 1 shown, mainly including ring-closing metathesis (RCM), ring-opening metathesis polymerization (ROMP), and cross metathesis (CM) reactions.

[0003] In the early exploration of the olefin metathesis mechanism, many hypotheses were proposed, and the mechanism proposed by Chauvin and his student Herisson in 1971, which is still recognized and consistent with experimental observations, is as Figure 2 shown. This mechanism believes that all types of olefin metathesis reactions proceed through the [2+2] cycloaddition of olefins and metal carbenes to form a metal heterocyclobutane intermediate, and then continue to proceed through ring cleavage. The most obvious feature of this mechanism is that all the elementary reactions in the catalytic cycle are reversible reactions. Therefore, generally, a mixture of many olefins is obtained. To make the metathesis reaction proceed completely, a method must be found to shift the equilibrium in one direction, such as removing the generated ethylene and other gases, generating polymers, or increasing the amount of one raw material, etc. The Chauvin mechanism provides an important theoretical basis for the development and design of catalysts and the understanding of catalyst activity.

[0004] Early metathesis catalysts with unclear structures were all prepared by mixing transition metal salts with supported or main group alkylating reagents. In 1990, the first molybdenum-based catalyst with a clear structure was reported by Schrock et al. Since such catalysts generally have higher initiation rates and catalytic performance compared to catalysts with unclear structures, they became relatively practical catalysts at that time. However, the activity of this type of catalyst is too sensitive to specific functional groups, and it is also very sensitive to air and moisture, and will decompose quickly when placed in humid air at room temperature. In 1995, Grubbs et al. developed a complex 1a ( Figure 3 ) that can stably exist in air but has lower activity than the Schrock type, which is called the first-generation Grubbs catalyst. In 1999, Grubbs et al. introduced an N-heterocyclic carbene (NHC) ligand, which is a stronger σ-electron-donating ligand compared to phosphine ligands. Compounds 2 and 3 ( Figure 3 ) obtained by replacing one of the PCy3 ligands in the first-generation Grubbs catalyst 1b with an NHC ligand are called the second-generation Grubbs catalysts, and the catalytic activity and thermal stability of this type of catalyst have been greatly improved.

[0005] For N-heterocyclic carbene (NHC) ligands, they are generally obtained by deprotonating carbene precursor salts, so the efficient synthesis of N-heterocyclic carbene precursor quaternary salts is crucial. Correspondingly, their synthesis methods are divided into three categories: 1) Closing the ring by introducing a carbene carbon atom to obtain an N-heterocyclic carbene precursor salt; 2) Closing the ring by introducing a part of the N atom to obtain an N-heterocyclic carbene precursor salt; 3) Closing the ring by connecting the ring skeleton with a nitrogen atom and a carbene carbon atom to obtain an N-heterocyclic carbene precursor salt. For example: In 2000, Nolan et al. used mesitylamine and 2,6-diisopropylaniline as raw materials, methanol as a solvent, and condensed with glyoxal under the catalysis of a small amount of acid to obtain a diimine compound; the diimine compound was then reacted with paraformaldehyde in the presence of hydrochloric acid to form a white precipitate, and after simple separation, an N,N'-bis(mesityl)imidazolium salt with a 70% yield could be obtained. In addition, in 1999, Arduengo et al. proposed using an organic amine and glyoxal as raw materials, condensing at room temperature to obtain a diimine compound; then refluxing in toluene in the presence of hydrochloric acid and triethyl orthoformate to obtain an N,N'-disubstituted imidazolium salt. Using this method, imidazolium salt compounds substituted with various groups can be obtained, especially suitable for the synthesis of imidazolium salts substituted with large steric hindrance aryl groups on N, and it is currently the most widely used method for the synthesis of symmetric imidazolium salts. However, since the condensation of an amine and glyoxal is an equilibrium reaction, if glyoxal condenses with two different amines, a mixed diimine compound will be obtained, so this method is not suitable for the synthesis of asymmetric imidazolium salts.

[0006] Transition metal carbene complexes have attracted great research interest due to their unique structures, reaction characteristics, and applications in organic synthesis and catalytic reactions. Through research on previous literature, we found that the synthesis of ruthenium carbene catalysts is basically achieved by changing ligands and the atoms coordinated with the central atom ruthenium to improve properties such as the catalytic efficiency, wide range of use, stability, and recyclability of the catalysts.

[0007] Based on this, the present application aims to provide a bridged bimetallic carbene catalyst ligand, its preparation method, and applications. Summary of the Invention

[0008] The object of the present application is to provide a bridged bimetallic carbene catalyst ligand, its preparation method, and applications.

[0009] According to the first aspect of the present application, the present application provides a bridged bimetallic carbene catalyst ligand, and the structure of the bridged bimetallic carbene catalyst ligand is shown in Formula I:

[0010]

[0011] Wherein, in Formula I, R1, R3, R4, R5, R6, R7, R8, R9, and R10 are each independently selected from any one of H, i-Pr, CH3, Cl, F, and NC; n = 1 - 9; N is selected from any one of Cl and Br.

[0012] In some embodiments of the present invention, the structure of the bridged bimetallic carbene catalyst ligand is shown in Formula II:

[0013]

[0014] Wherein, R1, R3, R4, and R5 are each independently selected from any one of H, i-Pr, and CH 3 selected from any one of them; R2 and R6 are each independently selected from any one of H, Cl, F, NC, and CH 3 selected from any one of them; n = 1 - 9; N is selected from any one of Cl and Br.

[0015] Compared with the carbene catalyst ligands used in the past, the bridged carbene catalyst ligand provided by the present application has dual active centers. Ligand exchange with a carbene catalyst precursor with a single active center can cause the active centers to aggregate, thereby obtaining a highly active carbene catalyst with dual centers, having higher reaction activity and atom economy. At the same time, the present invention uses a flexible aliphatic chain for bridging and a flexible molecular chain for bridging. The flexible molecular chain has smaller intermolecular forces and has greater expansion and contraction capabilities. By adjusting the length of the molecular chain, the type and position of substituents, and the intermolecular interactions, the ligand structure provided by the present invention has a wider molecular design space.

[0016] In some embodiments of the present invention, the structure of the bridged bimetallic carbene catalyst ligand includes any one of those shown in Formula I-1 to Formula I-6:

[0017]

[0018]

[0019] wherein, n = 1 to 9; N is selected from any one of Cl and Br.

[0020] The bridged carbene catalyst ligand having the above structure has two active centers. Compared with the traditional single-active-center carbene catalyst, the bridged carbene catalyst ligand provided in the present application has two active centers. Ligand exchange with the single-active-center carbene catalyst precursor can cause the active centers to aggregate, thereby obtaining a highly active bimetallic carbene catalyst with higher reaction activity and atom economy.

[0021] According to the second aspect of the present invention, the present invention also provides a preparation method of the bridged bimetallic carbene catalyst ligand as described in any one of the first aspect of the present invention. The preparation method includes the following steps:

[0022] (1) Synthesize aromatic ethylenediamine from 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride and aromatic amine;

[0023] (2) Cyclize the aromatic ethylenediamine and triethyl orthoformate under high temperature to form aromatic imidazolium;

[0024] (3) Bridge the aromatic imidazolium with a dihaloalkane to obtain the bridged bimetallic carbene catalyst ligand.

[0025] The preparation method of the bridged bimetallic carbene catalyst ligand provided by the present application. In this preparation method, aromatic ethylenediamine is synthesized from simple raw materials 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride and aromatic amine, and then cyclized with triethyl orthoformate under high temperature to form aromatic imidazolium, and finally the key ligand bridged imidazolium is obtained through bridging with a dihaloalkane at both ends. Through the above method, the bridged bimetallic carbene catalyst ligand can be directly synthesized by the "one-pot method". The preparation process is simple, and the bridged N-heterocyclic carbene ligand can be synthesized from simple and readily available basic chemical raw materials, and then ligand exchange is carried out with a single active center catalyst precursor to aggregate the active centers, thereby obtaining a bimetallic highly active ruthenium carbene catalyst. Compared with the prior art, the preparation method provided by the present application has the characteristics of short preparation period, simple operation, stable process, environmental friendliness, good atom economy, etc., and has great application prospects in industrial scale-up. At the same time, the prior art also involves methods for preparing hypercrosslinked N-heterocyclic carbene imidazolium salts ligands, but most of them use paraformaldehyde as the ring-closing reagent and need to additionally introduce p-toluenesulfonyl chloride - TMSCl to assist in ring closing, while the present application uses triethyl orthoformate for ring closing without the need to additionally introduce auxiliary reagents; and in terms of the bridging method, the prior art uses rigid aromatic compounds for bridging, while the present application uses a flexible aliphatic chain for bridging. By using this method for bridging, the intermolecular force of the flexible molecular chain is smaller, and it has greater expansion and contraction ability. By adjusting the length of the molecular chain, the type and position of substituents, and the intermolecular interaction, there is a wider molecular design space.

[0026] In some embodiments of the present invention, in step (1), the synthesis of aromatic ethylenediamine from 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride and aromatic amine includes: reacting 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride with aromatic amine in a reaction solvent under reflux conditions at 60 - 200 °C to synthesize the aromatic ethylenediamine. Specifically, the reaction temperature can be 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, 200 °C or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0027] In some embodiments of the present invention, the addition molar ratio of 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride to aromatic amine is 1:1 - 3; specifically, the addition molar ratio of 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride to aromatic amine can be: 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9 or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this value range are equally applicable. Preferably, the addition molar ratio of 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride to aromatic amine is 1:1 - 1.2.

[0028] In some embodiments of the present invention, in mol / L, the addition amount of 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride to the reaction solvent is 0.5 - 2:1. Specifically, in mol / L, the addition amount of 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride to the reaction solvent can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1 or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this value range are equally applicable. Preferably, in mol / L, the addition amount of 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride to the reaction solvent is 0.5 - 1:1.

[0029] In some embodiments of the present invention, the reaction solvent includes but is not limited to at least one of tetrahydrofuran, methyltetrahydrofuran, dioxane, toluene, xylene, ethylene glycol dimethyl ether, N,N-dimethylformamide, methyl isobutyl ketone, and butyl acetate.

[0030] In some embodiments of the present invention, the aromatic amine is selected from at least one of N,N,N-2,4,6-trimethylaniline, N,N,N-2,4,6-trimethoxyaniline, N,N,N-2,4,6-trifluoroaniline, 2,6-diisopropylaniline, and 2,6-dimethoxyaniline.

[0031] In some embodiments of the present invention, the synthesis of aromatic ethylenediamine from 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride and aromatic amine further includes: adding an aqueous sodium hydroxide solution to the reaction solution obtained after reacting with the aromatic amine, washing with saturated brine, drying with anhydrous sodium sulfate, and concentrating to obtain the aromatic ethylenediamine.

[0032] In some embodiments of the present invention, in step (2), the cyclization reaction of the aromatic ethylenediamine and triethyl orthoformate under high temperature to form an aromatic imidazolium includes: adding triethyl orthoformate and formic acid to the aromatic ethylenediamine, and carrying out a cyclization reaction under reflux at 60 - 200 °C for 1 - 10 h to obtain an aromatic imidazolium. Specifically, the reaction temperature can be 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, 200 °C or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this numerical range are equally applicable. Specifically, the reaction time can be 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0033] In some embodiments of the present invention, in terms of mol / L, the addition ratio of the ethylenediamine to the aromatic triethyl orthoformate is 0.5 - 4:1. Specifically, in terms of mol / L, the addition ratio of the ethylenediamine to the aromatic triethyl orthoformate can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4.0:1 or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this numerical range are equally applicable. Preferably, in terms of mol / L, the addition ratio of the ethylenediamine to the aromatic triethyl orthoformate is 0.5 - 2:1.

[0034] In some embodiments of the present invention, the addition amount of the formic acid is 0.01 - 0.1 mmol%. Specifically, the addition amount of the formic acid can be 0.01 mmol%, 0.02 mmol%, 0.03 mmol%, 0.04 mmol%, 0.05 mmol%, 0.06 mmol%, 0.07 mmol%, 0.08 mmol%, 0.09 mmol%, 0.1% or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0035] In some embodiments of the present invention, in step (3), the bridging of the aromatic imidazolium by the dihaloalkane to obtain the bridged bimetallic carbene catalyst ligand includes: mixing the aromatic imidazolium with a reaction solvent and the dihaloalkane, and reacting for 1 - 10 h under heating and reflux conditions to obtain the bridged bimetallic carbene catalyst ligand.

[0036] In some embodiments of the present invention, the temperature of the heating reflux is 60 - 300 °C. Specifically, the temperature of the heating reflux can be 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, 200 °C, 210 °C, 220 °C, 230 °C, 240 °C, 250 °C, 260 °C, 270 °C, 280 °C, 290 °C, 300 °C or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this value range are equally applicable. Specifically, the reaction time can be 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0037] In some embodiments of the present invention, based on mol / L, the addition ratio of the aromatic imidazolium to the reaction solvent is 0.5 - 4:1. Specifically, based on mol / L, the addition ratio of the aromatic imidazolium to the reaction solvent can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4.0:1 or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this value range are equally applicable. Preferably, based on mol / L, the addition ratio of the aromatic imidazolium to the reaction solvent is 0.5 - 2:1.

[0038] In some embodiments of the present invention, the addition molar ratio of the aromatic imidazolium to the dihaloalkane is 2.1 - 4:1. Specifically, the addition molar ratio of the aromatic imidazolium to the dihaloalkane can be 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4.0:1 or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this numerical range are equally applicable. Preferably, the addition molar ratio of the aromatic imidazolium to the dihaloalkane is 2.1 - 2:1.

[0039] In some embodiments of the present invention, the reaction solvent includes but is not limited to at least one of toluene, tetrahydrofuran, methyltetrahydrofuran, dioxane, xylene, ethylene glycol dimethyl ether, N,N - dimethylformamide, methyl isobutyl ketone, and butyl acetate.

[0040] In some embodiments of the present invention, the dihaloalkane is selected from at least one of 1,2 - dibromoethane, 1,3 - dibromopropane, 1,4 - dibromobutane, 1,5 - dibromopentane, 1,6 - dibromohexane, 1,2 - dichloroethane, 1,3 - dichloropropane, 1,4 - dichlorobutane, 1,5 - dichloropentane, and 1,6 - dichlorohexane.

[0041] According to the third aspect of the present invention, the present invention also provides a bridged bidentate carbene catalyst, the structure of which is shown in Formula II:

[0042]

[0043] Wherein, in Formula II, Ar is selected from any one of.

[0044] According to the fourth aspect of the present invention, the present invention also provides a preparation method of a bridged bidentate carbene catalyst as described in any one of the third aspects of the present invention, and the preparation method includes: obtaining by ligand substitution reaction of a bridged bidentate carbene catalyst ligand as described in any one of the first aspects of the present invention with a carbene catalyst precursor.

[0045] In some embodiments of the present invention, the preparation method includes: mixing the bridged bidentate carbene catalyst ligand with the carbene catalyst precursor and the reaction solvent, and stirring and reacting to obtain the bridged bidentate carbene catalyst.

[0046] In some embodiments of the present invention, the temperature of the stirring reaction is 60-100°C, and the time of the stirring reaction is 5-15 h. Specifically, the temperature of the stirring reaction can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this value range are equally applicable. Specifically, the time of the stirring reaction can be 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0047] In some embodiments of the present invention, the added molar ratio of the bridged bidentate carbene catalyst ligand to the carbene catalyst precursor is: 2.5-4:1. Specifically, the added molar ratio of the bridged bidentate carbene catalyst ligand to the carbene catalyst precursor can be: 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4.0:1 or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this value range are equally applicable. Preferably, the added molar ratio of the bridged bidentate carbene catalyst ligand to the carbene catalyst precursor is: 2.5-2:1.

[0048] In some embodiments of the present invention, based on mol / L, the added amount ratio of the bidentate carbene catalyst ligand to the bridging reaction solvent is: 0.1-0.5:1. Specifically, based on mol / L, the added amount ratio of the bidentate carbene catalyst ligand to the bridging reaction solvent is: 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1 or a range composed of any two of the above values, not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0049] In some embodiments of the present invention, the preparation method further includes: adding a base to the reaction system for reaction. In the solution provided in this application, the bridged bidentate carbene catalyst ligand can directly complex with the carbene catalyst precursor under the promotion of the base to obtain the target compound, and the added base serves as an acid-binding agent.

[0050] In some embodiments of the present invention, the base includes but is not limited to at least one of sodium hydride, potassium hydride, sodium carbonate, silver carbonate, cesium carbonate, sodium carbonate, potassium tert-butoxide, lithium hexamethyldisilazide, and lithium diisopropylamide.

[0051] In some embodiments of the present invention, the addition weight ratio of the base to the carbene catalyst precursor is 10:1 - 1:1. Specifically, the addition weight ratio of the base to the carbene catalyst precursor can be 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1 or a range composed of any two of the above values. It is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0052] In some embodiments of the present invention, the preparation method further includes: adding a reaction activator to the reaction system for reaction. In the solution provided by the present application, the bridged bidentate carbene catalyst ligand can directly complex with the carbene catalyst precursor under the promotion of a base to obtain the target compound. Adding a certain amount of reaction activator during the reaction process can increase the reaction yield of the bidentate carbene catalyst, especially increase the reaction yield of the bidentate ruthenium carbene catalyst.

[0053] In some embodiments of the present invention, the reaction activator includes but is not limited to at least one of iron(III) oxide, iron(III) chloride, cuprous oxide, aluminum chloride, iron(III) chloride, boron trifluoride, niobium pentachloride, and trifluoromethanesulfonates of lanthanide elements, etc.

[0054] In some embodiments of the present invention, the addition weight ratio of the reaction activator to the bridged bidentate carbene catalyst ligand is 50:1 - 1:1. Specifically, the addition weight ratio of the reaction activator to the bridged bidentate carbene catalyst ligand can be 50:1, 45:1, 40:1, 35:1, 30:1, 25:1, 20:1, 15:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1 or a range composed of any two of the above values. It is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0055] In some embodiments of the present invention, the preparation method further includes: after the reaction is completed, filtering, concentrating, and recrystallizing the reaction solution at least once to obtain the bridged bidentate carbene catalyst.

[0056] In some embodiments of the present invention, the purification reagent used for recrystallization is selected from any one of toluene / methanol, toluene / n-hexane, anhydrous ether / n-pentane, anhydrous ether / petroleum ether, ethyl acetate / petroleum ether, and dichloromethane / methanol.

[0057] In some embodiments of the present invention, in the purification reagent used for recrystallization, the volume ratio of the good solvent to the poor solvent is 1:5 - 1:100. Specifically, the volume ratio of the good solvent to the poor solvent can be 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, 1:100 or a range composed of any two of the above values. It is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0058] In some embodiments of the present invention, the carbene catalyst precursor includes a ruthenium carbene catalyst precursor.

[0059] In some embodiments of the present invention, the carbene catalyst precursor includes but is not limited to at least one of Grubbs first-generation catalyst, indenyl bis(tricyclohexylphosphine) ruthenium dichloride, and 2-isopropoxybenzylidene-tricyclohexylphosphine ruthenium dichloride.

[0060] According to the fifth aspect of the present application, the present application also provides a functional bridged bimetallic ruthenium carbene catalyst, and the structure of the functional bridged bimetallic ruthenium carbene catalyst includes any one of those shown in Formulas 1 to 18:

[0061]

[0062]

[0063] In some embodiments of the present invention, the functional bridged bimetallic ruthenium carbene catalyst is obtained by complex substitution of the bridged bimetallic carbene catalyst ligand described in any one of the first aspects of the present application with a ruthenium carbene catalyst.

[0064] In some embodiments of the present invention, the functional bridged bimetallic ruthenium carbene catalyst is a functional carbene adduct. The functional bridged bimetallic ruthenium carbene catalyst can be used to increase or enrich the catalytic polymerization activity of the ruthenium carbene catalyst, and even change the catalytic polymerization initiation mode of the catalyst to form a temperature-sensitive, light-sensitive, or chemically sensitive catalyst.

[0065] According to the sixth aspect of the present application, the present application also provides an application of the bridged bimetallic carbene catalyst described in any one of the fourth aspects of the present application in the field of cyclic olefin catalytic reactions.

[0066] In some embodiments of the present invention, the cyclic olefin catalytic reaction includes but is not limited to the ring-opening metathesis polymerization reaction of cyclic olefins.

[0067] In some embodiments of the present invention, the cyclic olefin includes but is not limited to at least one of dicyclopentadiene, tricyclopentadiene, norbornene, norbornadiene, cyclooctadiene.

[0068] According to the seventh aspect of the present application, the present application further provides a method for catalytic ring-opening metathesis polymerization of cyclic olefins, the method comprising: using the bridged bis-carbene catalyst described in the third aspect of the present application as a catalyst, and using the cyclic olefin as a substrate to carry out ring-opening metathesis polymerization reaction.

[0069] In some embodiments of the present invention, the method comprises: first dissolving the bridged bis-carbene catalyst in a solvent, stirring and heating, then mixing with the cyclic olefin and benzophenone to carry out ring-opening metathesis polymerization reaction.

[0070] In some embodiments of the present invention, the added weight ratio of the bridged bis-carbene catalyst to the cyclic olefin is 1:10000 - 1:100000. Specifically, the added weight ratio of the bridged bis-carbene catalyst to the cyclic olefin can be 1:10000, 1:11000, 1:12000, 1:13000, 1:14000, 1:15000, 1:16000, 1:17000, 1:18000, 1:19000, 1:20000, 1:25000, 1:30000, 1:35000, 1:40000, 1:45000, 1:50000, 1:55000, 1:60000, 1:65000, 1:70000, 1:75000, 1:80000, 1:85000, 1:90000, 1:95000, 1:100000 or a range composed of any two of the above values. It is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] (1) The present application provides a new bridged bis-carbene catalyst ligand. Compared with the carbene catalyst ligands used in the past, the bridged carbene catalyst ligand provided by the present application has dual active centers. Ligand exchange with the carbene catalyst precursor with a single active center can cause the active centers to aggregate, thereby obtaining a highly active carbene catalyst with dual centers, having higher reaction activity and atom economy.

[0073] (2) The present application provides a preparation method for the bridged bis-carbene catalyst ligand. Compared with the prior art, the preparation method provided by the present application has the characteristics of short preparation cycle, simple operation, stable process, environmental friendliness, good atom economy, etc., and has great application prospects in industrial scale-up. Description of the Drawings

[0074] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other embodiments can also be obtained based on these drawings.

[0075] Figure 1 It is a diagram showing the types of olefin metathesis reactions mentioned in the background art section of the present application;

[0076] Figure 2 It is a diagram showing the Chauvin mechanism of olefin metathesis reactions mentioned in the background art section of the present application;

[0077] Figure 3 It is a process flow diagram for the preparation of the bridged 1,2-diimidazolium ethane ligand 1 in Example 1;

[0078] Figure 4 It is the structural formula of the bridged 1,3-diimidazolium propane ligand 2 prepared in Example 2;

[0079] Figure 5 It is the structural formula of the bridged 1,2-diimidazolium ethane ligand 3 prepared in Example 3;

[0080] Figure 6 It is the structural formula of the bridged 1,2-diimidazolium ethane ligand 4 prepared in Example 4;

[0081] Figure 7 It is the structural formula of the bridged 1,2-diimidazolium ethane bis(benzylidene-tricyclohexylphosphine dichlororuthenium) (Ru-1) prepared in Example 5;

[0082] Figure 8 It is the structural formula of the bridged 1,2-diimidazolium ethane bis(indenyl-tricyclohexylphosphine dichlororuthenium) (Ru-2) prepared in Example 6;

[0083] Figure 9 It is the structural formula of the bridged 1,3-diimidazolium propane bis(benzylidene-tricyclohexylphosphine dichlororuthenium) (Ru-3) prepared in Example 7;

[0084] Figure 10 It is the structural formula of the bridged 1,3-diimidazolium propane bis(2-isopropoxybenzylidene-tricyclohexylphosphine dichlororuthenium) (Ru-4) prepared in Example 8. Detailed implementation manners

[0085] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art based on the present application belong to the scope of protection of the present application.

[0086] Example 1

[0087] This example provides a preparation method of a bridged bis-carbene catalyst ligand, including the following steps:

[0088] (1) Synthesize aromatic ethylenediamine: Add 20 g of 2-bromoethylamine hydrobromide (204.89 g / mol, 97.6 mmol) and 100 mL of toluene to a 250 mL three-necked flask. Under reflux at 110 °C, gradually add 14.8 mL of mesitylamine (135.21 g / mol, 105.8 mmol) to the above reaction solution dropwise using a constant-pressure dropping funnel. After reacting overnight, cool to room temperature, add 200 mL of sodium hydroxide aqueous solution (1 M) thereto, and wash with saturated brine three times (150 mL * 3). Dry with anhydrous sodium sulfate and concentrate to obtain a pale yellow oily liquid (N-2,4,6-mesityl-1,2-diaminoethane), with a crude yield of 96.7%;

[0089] (2) Form aromatic imidazolium: Transfer the pale yellow oily liquid (N-2,4,6-mesityl-1,2-diaminoethane) prepared in step (1) to a 100 mL three-necked flask, and add 40 mL of triethyl orthoformate and 2 drops of formic acid thereto. Stop the reaction after refluxing at 100 °C for 4 hours. After cooling to room temperature, add 50 mL of anhydrous ether to obtain a pale yellow crystalline powder, and then wash it three times with anhydrous ether (10 mL * 3). After drying, 25.6 g of 2-mesityl bromoimidazolium is obtained, with a yield of 98.1%; wherein, 1 H NMR (400 MHz, CDCl 3 ): 1.98 (s, 6H, CH3), 2.03 (s, 3H, CH3), 3.28 (t, J = 10.3 Hz, 2H, NCH2), 3.79 (t, J = 10.3 Hz, 2H, NCH2), 6.52 (s, 1H, N2CH), 6.64 (m, 2H, ArH);

[0090] (3) Formation of bridged imidazolium: Take another 100 ml three-necked flask, add 14.3 g of 2-mesityl bromoimidazolium (270.2 g / mol, 53.1 mmol) prepared in step (2), 2.1 mL of 1,2-dibromoethane (187.8 g / mol, 24.1 mmol) and 30 ml of toluene into the 100 ml three-necked flask, heat under reflux for 2 hours to stop the reaction, cool to room temperature and add 20 ml of cold anhydrous ether thereto. At this time, a large amount of solid precipitates. Wash it three times with anhydrous ether (10 mL * 3) to obtain 8.5 g of white solid powder, namely bridged 1,2-diimidazolium ethane ligand 1, with a yield of 87.2%; among them, 1 H NMR (400 MHz, CDCl3): 10.29 (s, 2H, NCHN), 7.21 (t, 4H, NCH2), 7.02 (s, 4H, ArH), 5.52 (m, 4H, NCH2), 4.60 (t, 4H, NCH2), 2.36 (s, 6H, CH3), 2.05 (s, 12H, CH3).

[0091] Among them, the process flow chart of the preparation of the bridged bimetallic carbene catalyst ligand in this example is as Figure 3 shown.

[0092] Example 2

[0093] Based on Example 1, this example provides a method for preparing a bridged bimetallic carbene catalyst ligand, which includes the following steps:

[0094] (1) Synthesis of aromatic ethylenediamine: The same as in Example 1;

[0095] (2) Formation of aromatic imidazolium: The same as in Example 1;

[0096] (3) Formation of bridged imidazolium: Take another 100 ml three-necked flask, add 14.3 g of 2-mesityl bromoimidazolium (270.2 g / mol, 53.1 mmol) prepared in step (2), 3.4 mL of 1,3-dibromopropane (278.3 g / mol, 24.1 mmol) and 30 ml of toluene into the 100 ml three-necked flask, heat under reflux for 2 hours to stop the reaction, cool to room temperature and add 20 ml of cold anhydrous ether thereto. At this time, a large amount of solid precipitates. Wash it three times with anhydrous ether (10 mL * 3) to obtain 12.8 g of white solid powder, namely bridged 1,3-diimidazolium propane ligand 2 (the structure is as Figure 4 shown), with a yield of 91.4%; among them, 1 H NMR (400 MHz, CDCl 3): 10.15 (s, 2H, NCHN), 8.67 (s, 2H, NCH), 7.08 (s, 2H, NCH), 7.00 (s, 4H, ArH), 4.96 (t, J = 4.0 Hz, 4H, CH2), 3.18 (m, 2H, CH2), 2.35 (s, 6H, CH3), 1.92 (s, 12H, CH3).

[0097] Example 3

[0098] Based on Example 1, this example provides a method for preparing a bridged bis-carbene catalyst ligand, which includes the following steps:

[0099] (1) Synthesis of aromatic ethylenediamine: Add 10 g of 2-bromoethylamine hydrobromide (204.89 g / mol, 48.8 mmol) and 50 mL of toluene to a 250 mL three-necked flask. Under reflux at 110 °C, gradually add 10 g of 2,6-diisopropylaniline (177.3 g / mol, 52.9 mmol) to the above reaction solution dropwise using a constant pressure dropping funnel. After reacting overnight, cool to room temperature, add 100 ml of sodium hydroxide aqueous solution (1 M) thereto, and wash with saturated brine three times (75 mL * 3). Dry with anhydrous sodium sulfate and concentrate to obtain a pale yellow oily liquid (2,6-diisopropylphenyl-1,2-diaminoethane), with a crude yield of 92.1%;

[0100] (2) Formation of aromatic imidazolium: Transfer the pale yellow oily liquid (2,6-diisopropylphenyl-1,2-diaminoethane) prepared in step (1) to a 100 mL three-necked flask, add 20 ml of triethyl orthoformate and 2 drops of formic acid thereto. Stop the reaction after refluxing at 100 °C for 4 hours. After cooling to room temperature, add 25 ml of anhydrous ether to obtain a pale yellow crystalline powder, and then wash it three times with anhydrous ether (10 mL * 3). Dry to obtain 14.9 g of 2,6-diisopropylphenyl bromoimidazolium, with a yield of 90.5%; among them, 1 H NMR (400 MHz, CDCl3): 1.18 (dd, J = 6.8, 5.3 Hz, 12H, CH3), 3.08 (sept, J = 6.8 Hz, 2H, CH3), 3.61 (t, J = 10.2 Hz, 2H, NCH2), 4.05 (t, J = 10.2 Hz, 2H, NCH2), 6.82 (s, 1H, NCH), 7.17 (d, J = 8.0 Hz, 2H, ArH), 7.29 (1H, t, J = 8.3 Hz, ArH);

[0101] (3) Formation of bridged imidazolium: Take another 100 ml three-necked flask, add 14.9 g of 2,6-diisopropylphenylimidazolium bromide (311.1 g / mol, 47.9 mmol) prepared in step (2), 2.2 mL of 1,2-dibromoethane (187.8 g / mol, 21.8 mmol), and 30 ml of toluene into the 100 ml three-necked flask. Heat under reflux for 2 hours to stop the reaction. Cool to room temperature and add 20 ml of cold anhydrous ether thereto. At this time, a large amount of solid precipitates. Wash it three times with anhydrous ether (10 mL * 3) to obtain 10.8 g of white solid powder, namely bridged 1,2-diimidazolium ethane ligand 3 (the structure is as Figure 5 shown), and the yield is 76.3%; among them, 1 1H NMR (400 MHz, CDCl3,): 10.21 (s, 2H, NCHN), 8.90 (s, 2H, NCH), 7.54 (t, J = 7.6 Hz, 2H, ArH), 7.30 (d, J = 7.6 Hz, 4H, ArH), 7.12 (s, 2H, NCH), 5.00 (t, J = 7.6 Hz, 4H, NCH2), 3.22 (m, 2H, CH2), 2.29 (m, 4H, CH), 1.22 (d, J = 6.8 Hz, 12H, CH3), 1.16 (d, J = 6.8 Hz, 12H, CH3).

[0102] Example 4

[0103] Based on Example 1, this example provides a preparation method of a bridged bimetallic carbene catalyst ligand, which includes the following steps:

[0104] (1) Synthesis of aromatic ethylenediamine: Add 20 g of 2-chloroethylamine hydrochloride (115.99 g / mol, 172.4 mmol) and 100 mL of toluene into a 250 ml three-necked flask. Under the reflux condition of 110 °C, gradually add 29.7 ml of mesitylaniline (135.21 g / mol, 189.6 mmol, 0.864 g / cm 3 ) dropwise to the above reaction solution with a constant pressure dropping funnel. After reacting overnight, cool to room temperature, add 200 ml of sodium hydroxide aqueous solution (1 M), and wash it 3 times with saturated brine (150 mL * 3), dry with anhydrous sodium sulfate, and concentrate to obtain a light yellow oily liquid (N-2,4,6-mesityl-1,2-diaminoethane), and the crude yield is 85.3%;

[0105] (2) Formation of aromatic imidazolium: Transfer the pale yellow oily liquid (N-2,4,6-trimethylphenyl-1,2-diaminoethane) prepared in step (1) to a 100 mL three-necked flask, add 40 mL of triethyl orthoformate and 2 drops of formic acid thereto, reflux at 100 °C for 6 hours and then stop the reaction. After cooling to room temperature, add 50 mL of anhydrous ether to obtain a pale yellow crystal powder, and then wash it three times with anhydrous ether (10 mL * 3), dry it to obtain 28.3 g of 2-trimethylphenylchloroimidazolium, with a yield of 73.6%; among them, 1 H NMR (400 MHz, CDCl 3 ): 1.96 (s, 6H, CH 3 ), 2.02 (s, 3H, CH 3 ), 3.27 (t, J = 10.3 Hz, 2H, NCH 2 ), 3.80 (t, J = 10.3 Hz, 2H, NCH 2 ), 6.50 (s, 1H, N 2 CH), 6.63 (m, 2H, ArH);

[0106] (3) Formation of bridged imidazolium: Take another 500 mL three-necked flask, add 28.0 g of 2-trimethylphenylchloroimidazolium (223.1 g / mol, 125.5 mmol) prepared in step (2), 4.6 mL of 1,2-dichloroethane (1.24 g / mL, 98.96 g / mol, 57.0 mmol) and 100 mL of toluene to the 100 mL three-necked flask, heat and reflux for 2 hours and then stop the reaction. After cooling to room temperature, add 80 mL of cold anhydrous ether thereto, and a large amount of solid will precipitate at this time. Wash it three times with anhydrous ether (100 mL * 3) to obtain 14.2 g of white solid powder, that is, bridged 1,2-diimidazolium ethane ligand 4 (the structure is as shown in Figure 6 ), with a yield of 67.2%; among them, 1 H NMR (400 MHz, CDCl 3 ): 10.26 (s, 2H, NCHN), 7.20 (t, 4H, NCH 2 ), 7.03 (s, 4H, ArH), 5.49 (m, 4H, NCH 2 ), 4.60 (t, 4H, NCH 2 ), 2.35 (s, 6H, CH 3 ), 2.05 (s, 12H, CH 3 ).

[0107] Example 5

[0108] This example provides a method for preparing a bridged bimetallic ruthenium carbene catalyst. In this example, the bridged 1,2-diimidazolium ethane ligand 1 prepared in Example 1 is used as the ligand for the preparation of the corresponding bridged bimetallic ruthenium carbene catalyst, which includes the following steps:

[0109] Take a 100 ml three-necked flask, add 5.7 g of bridged 1,2-diimidazolium ethane ligand 1 (566.4 g / mol, 10 mmol), 16.5 g of Grubbs first-generation catalyst (822.9 g / mol, 20 mmol), and 50 ml of toluene thereto. Stir and react at 80 °C for 8 hours. Monitor by TLC until the reaction is complete. Cool, filter, and wash to obtain 12.3 g of the target product, namely, bridged 1,2-diimidazolium ethane bis(benzylidene-tricyclohexylphosphine ruthenium dichloride) (Ru-1) (the structure is as Figure 7 shown), and the yield is 82.2%; 1 1H NMR (400 MHz, CDCl3): δ 19.62 (s, 2H), 8.73 (d, 4H), 7.30 (br, 6H), 7.21 (t, 4H, NCH2), 7.02 (s, 4H, ArH), 5.52 (m, 4H, NCH2), 4.60 (t, 4H, NCH2), 2.93 - 2.80, 1.98 - 1.17 (all m, 84H).

[0110] Example 6

[0111] Based on Example 5, this example provides a method for preparing a bridged bimetallic ruthenium carbene catalyst. The difference from Example 5 is that the Grubbs first-generation catalyst used in Example 5 is replaced with indenylbis(tricyclohexylphosphine) ruthenium dichloride, and the rest are the same. The method includes the following steps:

[0112] Take a 100 ml three-necked flask, add 5.7 g of bridged 1,2-diimidazolium ethane ligand 1 (566.4 g / mol, 10 mmol), 16.5 g of indenylbis(tricyclohexylphosphine) ruthenium dichloride (822.9 g / mol, 20 mmol), and 50 ml of toluene thereto. Stir and react at 80 °C for 8 hours. Monitor by TLC until the reaction is complete. Cool, filter, and wash to obtain 10.6 g of the target product, namely, bridged 1,2-diimidazolium ethane bis(indenyl-tricyclohexylphosphine ruthenium dichloride) (Ru-2) (the structure is as Figure 8 shown), and the yield is 62.3%; among them, 1 1H NMR (400 MHz, CDCl 3): 9.13 - 7.23 (m, 10H, phenyl), 7.21 (t, 4H, NCH2), 7.16 - 7.1 (m, 10H, H5) 7.02 (s, 4H, ArH), 5.52 (m, 4H, NCH2), 4.60 (t, 4H, NCH2), 2.36 (s, 6H, CH3), 2.05 (s, 12H, CH3). 1.71 (m, 6H, PCy3), 1.57 - 1.09 (m, 90H, PCy3).

[0113] Example 7

[0114] This example is based on Example 5 and provides a method for preparing a bridged bimetallic ruthenium carbene catalyst. The difference between this example and Example 5 is that the bridged 1,3 - diimidazolium propane ligand 2 prepared in Example 2 is used as the ligand for the preparation of the corresponding bridged bimetallic ruthenium carbene catalyst, and the steps are as follows:

[0115] Take a 100 ml three - necked flask, add 5.7 g of bridged 1,3 - diimidazolium propane ligand 2 (566.4 g / mol, 10 mmol), 16.5 g of Grubbs first - generation catalyst (822.9 g / mol, 20 mmol) and 50 ml of toluene into it. Stir and react at 80 °C for 8 hours. Monitor the reaction by TLC until it ends. Cool, filter, and wash to obtain 13.1 g of the target product, namely, bridged 1,3 - diimidazolium propane bis(benzylidene - tricyclohexylphosphine ruthenium dichloride) (Ru - 3) (the structure is as Figure 9 shown), and the yield is 87.1%; 1 HNMR (400 MHz, CDCl3): δ 19.75 (s, 2H), 8.68 (d, 4H), 7.52 (br, 6H), 7.23 (t, 2H, NCH2), 4.63 (t, 2H, NCH2), 7.00 (s, 4H, ArH), 4.96 (t, J = 4.0 Hz, 4H, CH2), 3.18 (m, 2H, CH2), 2.93 - 2.80, 1.98 - 1.17 (all m, 84H).

[0116] Example 8

[0117] This example is based on Example 5 and provides a method for preparing a bridged bimetallic ruthenium carbene catalyst. The difference from Example 5 is that the Grubbs first - generation catalyst used in Example 5 is replaced by 2 - isopropoxybenzylidene - tricyclohexylphosphine ruthenium dichloride, and the rest are the same. The steps are as follows:

[0118] Take a 100 ml three-necked flask, add 5.7 g of bridged 1,2-diimidazolium ethane ligand 1 (566.4 g / mol, 10 mmol), 16.5 g of 2-isopropoxybenzylidene-tricyclohexylphosphine ruthenium dichloride (822.9 g / mol, 20 mmol) and 50 ml of toluene thereto, stir and react at 80 °C for 8 hours, monitor by TLC until the reaction is complete, cool, filter, and wash to obtain 13.8 g of the target product, namely, bridged 1,3-diimidazolium propane bis(2-isopropoxybenzylidene-tricyclohexylphosphine ruthenium dichloride) (Ru-4) (the structure is as shown in Figure 10 shown), and the yield is 85.1%; among them, 1 H NMR (400 MHz, CDCl3): δ 19.73 (s, 2H), 8.82 (s, 2H), 7.53 (br, 6H), 7.33 (t, 2H, NCH2), 4.63 (t, 2H, NCH2), 7.00 (s, 4H, ArH), 4.96 (t, J = 4.0 Hz, 4H, NCH2), 3.18 (m, 2H, CH2), 2.35 (s, 6H, CH3), CH3). 2.83 - 1.27 (all m, 78H).

[0119] Example 9

[0120] This example provides a specific application of a bridged bimetallic ruthenium carbene catalyst. Specifically, the carbene catalyst prepared in Example 5: bridged 1,2-diimidazolium ethane bis(benzylidene-tricyclohexylphosphine ruthenium dichloride) (Ru-1) is subjected to a polymerization reaction. The specific steps are as follows:

[0121] Add 50 g of dicyclopentadiene and 0.25 g of benzophenone to a 100 ml beaker. Separately, dissolve 2 mg of the bridged bimetallic ruthenium carbene catalyst (Ru-1) prepared in Example 5 in 1 ml of toluene, stir and heat at 40 °C, and add the stirred and heated catalyst to the dicyclopentadiene base material. The base material rapidly polymerizes and solidifies within 10 min, and the polymerization yield is 99.8%.

[0122] Example 10

[0123] Based on Example 9, this example provides a specific application of a bridged bimetallic ruthenium carbene catalyst. Specifically, the carbene catalyst used in Example 9, which is bridged 1,2-diimidazolium ethane bis(benzylidene-tricyclohexylphosphine ruthenium dichloride) (Ru-1) prepared in Example 5, is replaced with bridged 1,2-diimidazolium ethane bis(indenyl-tricyclohexylphosphine ruthenium dichloride) (Ru-2) prepared in Example 6 for the polymerization reaction. The specific steps are as follows:

[0124] Add 50 g of dicyclopentadiene and 0.25 g of benzophenone into a 100 ml beaker. Separately, dissolve 2 mg of bridged 1,2-diimidazolium ethane bis(indenyl-tricyclohexylphosphine ruthenium dichloride) (Ru-2) prepared in Example 6 in 1 ml of toluene, stir and heat at 40 °C, and add the stirred and heated catalyst into the dicyclopentadiene base material. The base material rapidly polymerizes and solidifies into a shape within 10 min, and the polymerization yield is 99.2%.

[0125] Example 11

[0126] This example provides a specific application of a bridged bimetallic ruthenium carbene catalyst based on Example 9. Specifically, the carbene catalyst used in Example 9, which is bridged 1,2-diimidazolium ethane bis(benzylidene-tricyclohexylphosphine ruthenium dichloride) (Ru-1) prepared in Example 5, is replaced with bridged 1,3-diimidazolium propane bis(benzylidene-tricyclohexylphosphine ruthenium dichloride) (Ru-3) prepared in Example 7 for the polymerization reaction. The specific steps are as follows:

[0127] Add 50 g of dicyclopentadiene and 0.25 g of benzophenone into a 100 ml beaker. Separately, dissolve 2 mg of bridged 1,3-diimidazolium propane bis(benzylidene-tricyclohexylphosphine ruthenium dichloride) (Ru-3) prepared in Example 7 in 1 ml of toluene, stir and heat at 40 °C, and add the stirred and heated catalyst into the dicyclopentadiene base material. The base material rapidly polymerizes and solidifies into a shape within 10 min, and the polymerization yield is 99.6%.

[0128] Example 12

[0129] This example provides a specific application of a bridged bimetallic ruthenium carbene catalyst based on Example 9. Specifically, the carbene catalyst used in Example 9, which is bridged 1,2-diimidazolium ethane bis(benzylidene-tricyclohexylphosphine ruthenium dichloride) (Ru-1) prepared in Example 5, is replaced with bridged 1,3-diimidazolium propane bis(2-isopropoxybenzylidene-tricyclohexylphosphine ruthenium dichloride) (Ru-4) prepared in Example 8 for the polymerization reaction. The specific steps are as follows:

[0130] Add 50 g of dicyclopentadiene and 0.25 g of benzophenone into a 100 ml beaker. Separately, dissolve 2 mg of bridged 1,3-diimidazolium propane bis(2-isopropoxybenzylidene-tricyclohexylphosphine ruthenium dichloride) (Ru-4) prepared in Example 8 in 1 ml of toluene, stir and heat at 40 °C, and add the stirred and heated catalyst into the dicyclopentadiene base material. The base material rapidly polymerizes and solidifies into a shape within 10 min, and the polymerization yield is 99.9%.

[0131] Comparative Example 1

[0132] This comparative example provides an application of a carbene catalyst based on Example 9. The difference from Example 9 is that the bridged bimetallic ruthenium carbene catalyst (Ru-1) is replaced with a Grubbs 2nd generation catalyst, and the rest are the same. The polymerization yield is 99.2%.

[0133] Effect Example

[0134] This effect example further tests the mechanical properties of the polymers obtained in Examples 9, 10, 11, 12 and Comparative Example 1. The conventional property tests of polycyclopentadiene reaction injection products include: tensile test, static bending test, impact test. The above tests are used as general test methods for some conventional mechanical properties of polymer materials. These methods are simple to operate, have strict unified regulations on technical conditions, and are relatively fast in testing. The results can be used as a basis for comparing the quality of different materials, quality control in production and quality acceptance. Some can also be used as performance indicators in applications and data for engineering design. In order to compare test data, it is required that the technical conditions and operation methods of the test methods be unified, standardized, and the equipment and instruments be standardized. According to the perfection degree of these methods, they are respectively divided into internal standard methods, enterprise standard methods, department (or bureau) standard methods, national standard methods, and even international standard methods at home and abroad. As shown in the following table:

[0135] Table 1 Conventional Property Test Standards for Polycyclopentadiene Reaction Injection Products (Tested by National Standards)

[0136]

[0137] In this example, the specific test methods adopted are as follows:

[0138] (1) For the test instruments and standards of tensile modulus, yield elongation, tensile strength, bending strength, and bending modulus: CMT6104 microcomputer-controlled electronic universal testing machine. Specimen preparation: thickness 4mm; use type 1A or other types of specimens; there are no visible cracks, scratches or other defects on the specimen surface. Test operation steps: (1) Install the fixture: Prepare the fixture according to the specimen situation and install it on the fixture seat; (2) Set the limit device; (3) Select the test plan and input user parameters; (4) Start the test; (5) When the test is over, record the generated data and charts;

[0139] (2) For impact strength testing instruments and standards: The test reference standard is (GB / T 1843); the test instrument is a cantilever beam impact tester. Specimen: 4 mm thick; should not warp, opposite surfaces should be parallel to each other, and adjacent surfaces should be perpendicular to each other; there should be no scratches, pitting, depressions, and flash on the specimen surface and edges. Test operation steps: (1) Select the test scheme and input user parameters; (2) Select the pendulum and place it at the highest position of the instrument; (3) Conduct a blank impact test; (4) Input data such as spline size, notch type, pendulum type, etc. in the test data list; (5) Rotate the handwheel to loosen the jaws, place the sample in the jaws, align the specimen with the center using the cantilever beam specimen alignment template, and then rotate the handwheel to clamp the specimen; (6) Start the cantilever beam impact; (7) The test ends.

[0140] The results obtained based on the above test method are shown in Table 2 as follows:

[0141] Table 2

[0142]

[0143]

[0144] According to the results shown in Table 2, compared with Grubbs II, the mechanical properties such as tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength, and yield elongation of the polymer obtained by polymerizing with the catalyst provided in this application have been significantly improved.

[0145] It can be understood that this application is described through some embodiments. Those skilled in the art know that without departing from the spirit and scope of this application, various changes or equivalent replacements can be made to these features and embodiments. Additionally, under the teaching of this application, these features and embodiments can be modified to adapt to specific situations and materials without departing from the scope of this application. Therefore, this application is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by this application.

Claims

1. A bridged dual-center carbene catalyst ligand, characterized in that: The structure of the bridged dual-center carbene catalyst ligand is shown in Formula I: Wherein, in Formula I, R1, R3, R4, R5, R6, R7, R8, R9, and R10 are independently selected from any one of H, i-Pr, CH3, Cl, F, and NC; n=1 to 9; and N is selected from any one of Cl and Br.

2. The bridged dual-center carbene catalyst ligand according to claim 1, characterized in that: The structure of the bridged dual-center carbene catalyst ligand includes any one of Formula I-1 to Formula I-6: Wherein, n=1-9; N is selected from any one of Cl and Br.

3. A method for preparing a bridged dual-center carbene catalyst ligand as claimed in any one of claims 1 to 2, characterized in that: The preparation method comprises the following steps: (1) synthesizing aromatic ethylenediamine by reacting 2-bromoethylamine hydrobromide or 2-chloroethylamine hydrochloride with aromatic amine; (2) subjecting the aromatic ethylenediamine and triethyl orthoformate to a cyclization reaction at high temperature to form an aromatic imidazolium; (3) Bridging the aromatic imidazolium through a double-terminal halogenated hydrocarbon to obtain the bridged double-center carbene catalyst ligand.

4. The preparation method according to claim 3, characterized in that: In step (1), the synthesis of aromatic ethylenediamine by reacting 2-bromoethylamine hydrobromide or 2-chloroethylamine hydrochloride with aromatic amine comprises: placing 2-bromoethylamine hydrobromide or 2-chloroethylamine hydrochloride in a reaction solvent, reacting with aromatic amine under reflux conditions of 60-200° C., to synthesize the aromatic ethylenediamine; Preferably, the molar ratio of the 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride to the aromatic amine is 1:1-3; in terms of mol / L, the amount of the 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride to the reaction solvent is 0.5-2:1; Preferably, the reaction solvent in the step of synthesizing aromatic ethylenediamine includes but is not limited to at least one of tetrahydrofuran, methyltetrahydrofuran, dioxane, toluene, xylene, ethylene glycol dimethyl ether, N,N-dimethylformamide, methyl isobutyl ketone and butyl acetate; Preferably, the aromatic amine is selected from at least one of N,N,N-2,4,6-trimethylolamine, N,N,N-2,4,6-trimethoxyphenylamine, N,N,N-2,4,6-trifluorophenylamine, 2,6-diisopropylaniline and 2,6-dimethoxyaniline; Preferably, the synthesis of aromatic ethylenediamine by 2-bromoethylamine hydrobromide / or 2-chloroethylamine hydrochloride and aromatic amine further comprises: adding aqueous sodium hydroxide solution to the reaction solution obtained after the reaction with the aromatic amine, washing with saturated brine, drying with anhydrous sodium sulfate, and concentrating to obtain the aromatic ethylenediamine.

5. The preparation method according to claim 3, characterized in that: In step (3), the step of bridging the aromatic imidazolium with a double-terminal halogenated hydrocarbon to obtain the bridged dual-center carbene catalyst ligand comprises: mixing the aromatic imidazolium with a reaction solvent and a double-terminal halogenated hydrocarbon, and reacting the mixture under heating reflux for 1-4 hours to obtain the bridged dual-center carbene catalyst ligand; Preferably, in mol / L, the addition ratio of the aromatic imidazolium to the reaction solvent is 0.5-4:1; the addition molar ratio of the aromatic imidazolium to the dihydrogen halide is 2.1-4:

1. Preferably, the reaction solvent includes but is not limited to at least one of toluene, tetrahydrofuran, methyltetrahydrofuran, dioxane, xylene, ethylene glycol dimethyl ether, N,N-dimethylformamide, methyl isobutyl ketone and butyl acetate; Preferably, the double-terminal halogenated hydrocarbon is selected from at least one of 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane, 1,6-dibromohexane, 1,2-dichloroethane, 1,3-dichloropropane, 1,4-dichlorobutane, 1,5-dichloropentane and 1,6-dichlorohexane.

6. A bridged dual-center ruthenium carbene catalyst, characterized in that: Its structure is shown in Formula II: Wherein, in formula II, Ar is selected from Any one of .

7. A method for preparing a bridged dual-center ruthenium carbene catalyst as claimed in claim 6, characterized in that: The preparation method comprises: obtaining the ligand by performing a ligand replacement reaction between the bridged dual-center carbene catalyst ligand according to any one of claims 1 to 2 and a ruthenium carbene catalyst precursor; Preferably, the preparation method comprises: mixing the bridged dual-center carbene catalyst ligand with a ruthenium carbene catalyst precursor and a reaction solvent, and stirring the mixture to react to obtain the bridged dual-center ruthenium carbene catalyst; Preferably, the molar ratio of the bridged dual-center carbene catalyst ligand to the carbene catalyst precursor is: 2.5-4:1; In terms of mol / L, the ratio of the added amount of the dual-center carbene catalyst ligand to the bridging reaction solvent is: 0.1-0.5:1; Preferably, the preparation method further comprises: adding a base to the reaction system for reaction; the base includes but is not limited to at least one of sodium hydride, potassium hydride, sodium carbonate, silver carbonate, cesium carbonate, sodium carbonate, potassium tert-butoxide, lithium hexamethyldisilazide, and lithium diisopropylamide; the weight ratio of the base to the carbene catalyst precursor is 10:1-1:1; Preferably, the preparation method further comprises: adding a reaction activator to the reaction system for reaction; the reaction activator includes but is not limited to at least one of ferric oxide, ferric chloride, cuprous oxide, aluminum chloride, ferric chloride, boron trifluoride, niobium pentachloride and trifluoromethanesulfonate of lanthanide elements; preferably, the weight ratio of the reaction activator to the bridged dual-center carbene catalyst ligand is 50:1-1:1; Preferably, the preparation method further comprises: after the reaction is completed, filtering, concentrating, and recrystallizing the reaction solution at least once to obtain the bridged dual-center carbene catalyst; Preferably, the ruthenium carbene catalyst precursor includes but is not limited to at least one of Grubbs first generation catalyst, indenyl bistricyclohexylphosphine ruthenium dichloride, and 2-isopropoxybenzylidene-tricyclohexylphosphine ruthenium dichloride.

8. A functional bridged dual-center ruthenium carbene catalyst, characterized in that: The structure of the functional bridged dual-center ruthenium carbene catalyst includes any one of Formula 1 to Formula 18: Preferably, the functional bridged dual-center ruthenium carbene catalyst is obtained by complexing and replacing the bridged dual-center carbene catalyst ligand described in any one of claims 1 to 2 with a ruthenium carbene catalyst.

9. Use of the bridged dual-center carbene catalyst as claimed in claim 6 in the field of cyclic olefin catalytic reaction; Preferably, the cyclic olefin catalytic reaction includes but is not limited to the ring-opening metathesis polymerization reaction of cyclic olefins; Preferably, the cyclic olefin includes but is not limited to at least one of dicyclopentadiene, tricyclopentadiene, norbornene, norbornadiene and cyclooctadiene.

10. A method for catalyzing the ring-opening metathesis polymerization of cyclic olefins, characterized in that: The method comprises: using the bridged dual-center carbene catalyst of claim 6 as a catalyst and the cyclic olefin as a substrate to carry out a ring-opening metathesis polymerization reaction; Preferably, the method comprises: first dissolving the bridged dual-center carbene catalyst in a solvent, stirring and heating the mixture, and then mixing the mixture with a cyclic olefin and benzophenone to perform a ring-opening metathesis polymerization reaction; Preferably, the weight ratio of the bridged dual-site carbene catalyst to the cyclic olefin is 1:10000-1:100000.

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