A magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex, its preparation method and application

Abstract

This invention discloses a magnetically supported thioether-chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd, its preparation method, and its applications. Using an amino alcohol as a starting material, an imidazole derivative containing a hydroxyl group on the N-substituent is obtained through a condensation and ring-closing reaction. This derivative is then subjected to substitution reactions with thionyl chloride and cyclohexanethiol sequentially to obtain an imidazole derivative containing a thioether on the N-substituent. This derivative is then reacted with 1,3-dibromopropane to obtain an N-bromopropyl-N'-cyclohexane thioether-substituted imidazole bromium salt. This salt is then reacted with Pd(OAc)₂ or PdCl₂ via a direct metallization reaction to obtain the N-bromopropyl-substituted thioether-chelated nitrogen heterocyclic carbene palladium complex NHC-Pd. The NHC-Pd complex is then reacted with amino-functionalized magnetic nanoparticles (MNPs-NH₂) to prepare the magnetically supported thioether-chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd. It not only possesses the activity of homogeneous nitrogen heterocyclic carbene palladium catalysts, but also has a simple synthesis method, high yield, and is easy to separate and reuse in catalytic C-C bonding reactions, showing good application prospects in the field of catalysis.

Description

Technical Field

[0001] This invention belongs to the field of organic compound synthesis and application technology, and relates to a magnetically supported thioether chelate nitrogen heterocyclic carbene palladium complex, its preparation method and application. Background Technology

[0002] In various types of organic synthesis, the Suzuki-Miyaura cross-coupling reaction has attracted much attention due to its general applicability in industrial production and its great potential to synthesize a wide range of intermediates and compounds [(a) N. Miyaura, K. Yamada]. Tetrahedron Lett . 1979, 20, 3437–3440; (b) N. Miyaura. Chem. Rev . 1995,95, 2457–2483; (c) TE Barder, SD Walker, JR Martinelli, SLBuchwald. ACS. [2005, 127, 4685–4696.]. To achieve operability and efficiency in reactions, many transition metal catalysts and their complexes have been applied in various systems [FS Han]. Chem. Soc. Rev. 2013, 42, 5270–5298.]. Nitrogen heterocyclic carbene palladium complexes (NHC-Pd) combine the catalytic activity of noble metals with the advantages of NHC's low toxicity, strong σ-donor, high dissociation energy, and environmental stability, and have numerous successful application examples and broad application prospects [(a)PG Gildner, TJ Colacot. Organometallics. 2015, 34, 5497–5508. (b) RDJFroese, C. Lombardi, M. Pompeo, RP Rucker, MG Acc. Chem. Res. 2017, 50, 2244–2253.

[0003] When an N-substituent is attached to a coordinating heteroatom group, this heteroatom and the carbene carbon in the nitrogen heterocyclic carbene coordinate with the same metal center, forming a chelated nitrogen heterocyclic carbene metal complex, as shown in the structural formula. Structural formula of the chelated nitrogen heterocyclic carbene palladium complex: Due to its stable structure and excellent catalytic performance, it exhibits good catalytic effects in CC coupling reactions such as the Heck reaction, Suzuki-Miyaura reaction, and Sonogashira reaction, and is widely used as a homogeneous catalyst [(a) Wang Z, Zheng T, Sun H, et al. New Journal of Chemistry, 2018, 42, 11465-11470. (b) Sharma KN, Satrawala N, Srivastava AK, et al. Organic & Biomolecular Chemistry, 2019, 17, 8969-8976. (c) Ouyang JS, Zhang X, Pan B, et al. Organic Letters [2023, 25, 7491–7496.]. Homogeneous catalysts are difficult to separate and recover, have high operating costs, and pollute the products, which greatly hinders the further application of nitrogen heterocyclic carbene palladium complexes in the field of catalysis. By immobilizing the nitrogen heterocyclic carbene precursor onium salt onto a magnetic matrix and then reacting it with a palladium precursor (palladium chloride or palladium acetate), a magnetically supported heterogeneous nitrogen heterocyclic carbene palladium catalyst can be obtained. During use, it can be separated, recovered, and reused by an external magnet [(a)Martínez-Olid F, Andrés R, de Jesus E, et al.]. Dalton Transactions ,2016, 45, 11633-11638. (b)Esmaeilpour M, Sardarian AR, Firouzabadi. Journal of Organometallic Chemistry , 2018, 873, 22-34. (c)Gou G, Niu Z, HanW. Materials Chemistry and Physics [2019, 230, 145-150.] The structural spectroscopic characterization of nitrogen heterocyclic carbene metal complexes in the supported catalysts synthesized by this method is not comprehensive enough. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a magnetically supported sulfide-chelated nitrogen heterocyclic carbene palladium complex and its preparation method. This supported catalyst not only possesses the activity of a homogeneous nitrogen heterocyclic carbene palladium catalyst, but also features a simple synthesis method, high yield, and easy separation and reuse in catalytic C / C bonding reactions, significantly reducing costs and demonstrating promising application prospects in the field of catalysis. Furthermore, it provides a new approach for the comprehensive spectroscopic characterization of the metal complex structure in magnetically supported nitrogen heterocyclic carbene complexes.

[0005] The technical solution of this invention is implemented as follows:

[0006] A magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex has the following structural formula:

[0007] .

[0008] The method for preparing the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex of the present invention comprises three steps:

[0009] I. Synthesis of the thioether chelate NHC-Pd nitrogen heterocyclic carbene palladium complex, the synthetic route is as follows:

[0010] ;

[0011] II. Synthesis of amino-functionalized magnetic nanoparticles (MNPs-NH2) (refer to literature) N -heterocycliccarbene-Pd(II) complex based on theophylline supported on Fe3O4@SiO2nanoparticles: Highly active, durable and magnetically separable catalystforgreen Suzuki-Miyaura and Sonogashira-Hagihara coupling reactions (prepared), the synthesis route is as follows:

[0012] ;

[0013] III. Synthesis of the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd, the synthetic route is as follows:

[0014] .

[0015] The specific experimental steps are as follows:

[0016] (1) L-phenylpropanol and ammonium chloride were dissolved in methanol, cooled, and then formaldehyde and glyoxal were added dropwise to react. After drying, the mixture was dissolved in NaOH solution, extracted, the organic phases were combined, dried, filtered, the solvent was removed under reduced pressure, and the product was purified by column chromatography to obtain (S)-2-(1-imidazolyl)-3-phenylpropanol.

[0017] (2) Mix (S)-2-(1-imidazolyl)-3-phenylpropanol from step (1) with anhydrous sodium carbonate, add SOCl2 dropwise to react, evaporate the reaction solution to dryness, adjust the pH to alkaline, extract, combine the organic phases, dry, filter, remove the solvent under reduced pressure to obtain (S)-1-(1-chloro-3-phenyl-2-propyl)-imidazolium;

[0018] (3) Add cyclohexylthiol to NaOH ethanol solution, then add (S)-1-(1-chloro3-phenyl-2-propyl)-imidazol ethanol solution from step (2), heat to react, evaporate the reaction solution to dryness, add water, extract, combine organic phases, dry, filter, remove solvent under reduced pressure, and purify by column chromatography to obtain (S)-1-(1-cyclohexylthio-3-phenyl-2-propyl)-imidazol;

[0019] (4) The (S)-1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium from step (3) and 1,3-dibromopropane were mixed and reacted. After cooling, the product was separated and purified by column chromatography to obtain N-(1-cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide salt;

[0020] (5) The N-(1-cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide salt, palladium acetate or palladium chloride, alkaline substances, sodium bromide and organic solvent from step (4) are stirred and reacted under nitrogen conditions. The organic solvent is removed under reduced pressure, and the N-bromopropyl-substituted thioether chelated nitrogen heterocyclic carbene palladium complex NHC-Pd is obtained by column chromatography.

[0021] (6) FeCl3 . 6H2O and FeCl2 . 4H2O was dissolved in water, heated and stirred to obtain an orange-yellow suspension, and then ammonia was added dropwise to obtain a black suspension. After the reaction was cooled, the product was collected, washed with water and ethanol and dried to obtain hydroxyl-functionalized magnetic nanoparticles MNPs-OH.

[0022] (7) Disperse the hydroxyl-functionalized magnetic nanoparticles MNPs-OH from step (6) in an aqueous ethanol solution, add 3-aminopropyltriethoxysilane dropwise to react, cool, wash with water and ethanol in sequence and dry to obtain amino-functionalized magnetic nanoparticles MNPs-NH2.

[0023] (8) The N-bromopropyl-substituted thioether chelated nitrogen heterocyclic carbene palladium complex NHC-Pd from step (5) and the amino-functionalized magnetic nanoparticles MNPs-NH2 from step (7) were added to an organic solvent for reaction, cooled, and washed and dried with water and ethanol in sequence to obtain the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd.

[0024] In step (1) above, L-phenylalanine, ammonium chloride, formaldehyde and glyoxal are in equimolar ratio, with formaldehyde concentration of 36%, glyoxal concentration of 40%, L-phenylalanine concentration in methanol of 0.5 mol / L, reaction conditions of 60℃, 5h, sodium hydroxide solution concentration of 2 mol / L, and volume of 150 mL.

[0025] In step (2) above (S )-2-(1-imidazolyl)-3-phenylpropanol and anhydrous sodium carbonate are in an equimolar ratio, S The concentration of 2-(1-imidazolyl)-3-phenylpropanol in SOCl2 was 2 mol / L.

[0026] In step (3) above, the concentration of the NaOH ethanol solution is 1 mol / L. S The concentration of the ethanol solution of (S)-1-(1-chloro3-phenyl-2-propyl)-imidazolium was 1 mol / L, the volume ratio of NaOH ethanol solution to (S)-1-(1-chloro3-phenyl-2-propyl)-imidazolium ethanol solution was 3:1, the concentration of cyclohexanethiol in NaOH ethanol solution was 1 mol / L, the reaction conditions were 70℃ and 6h, the solvent used for extraction in steps (1)-(3) was dichloromethane, and the drying agent used for drying was anhydrous Na2SO4.

[0027] In step (4) above, the concentration of (S)-1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium in 1,3-dibromopropane is 1.17 mol / L, and the reaction conditions are a temperature of 90℃ and a time of 8h.

[0028] In step (5) above, the organic solvent is one of tetrahydrofuran, dichloromethane, toluene, 1,4-dioxane, acetonitrile, dimethylformamide, dimethylacetamide, and dimethyl sulfoxide; the alkaline substance is one of sodium acetate, potassium acetate, sodium tert-butoxide, potassium tert-butoxide, sodium tert-pentoxide, and potassium tert-pentoxide; the molar ratio of N-(1-cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide, palladium acetate or palladium chloride, the alkaline substance, and sodium bromide is 1:1:2:4; the concentration of imidazolium bromide in the organic solvent is 0.2125 mol / L; and the reaction time is 12 h.

[0029] In step (6) above, FeCl3 . 6H2O and FeCl2 . The molar ratio of FeCl2 to 4H2O is 2:1. . The concentration of 4H2O in water is 0.087 mol / L. The heating conditions are 85℃ for 30 min, the reaction conditions are 30 min, and the drying temperature is 70℃.

[0030] In step (7) above, the volume concentration of the ethanol aqueous solution is 50%, the volume ratio of the ethanol aqueous solution to 3-aminopropyltriethoxysilane is 6:1, and the concentration of the hydroxyl-functionalized magnetic nanoparticles MNPs-OH in the ethanol aqueous solution is 50 g / L.

[0031] In step (8) above, the organic solvent is one of methanol, tetrahydrofuran, toluene, 1,4-dioxane, acetonitrile, and ethylene glycol dimethyl ether. The mass ratio of N-bromopropyl-substituted thioether chelated nitrogen heterocyclic carbene palladium complex NHC-Pd to amino-functionalized magnetic nanoparticles MNPs-NH2 is 3:40. The concentration of amino-functionalized magnetic nanoparticles MNPs-NH2 in the organic solvent is 50 g / L. The reaction conditions are temperature 20-100℃, time 24 h, and drying temperature 70℃.

[0032] The magnetically supported thioether-chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd synthesized in this invention possesses unique structural characteristics and exhibits highly efficient catalytic performance in the Suzuki-Miyaura coupling reaction and the reduction of p-nitrophenol. It plays a crucial role in the efficient synthesis of Suzuki-Miyaura coupling products and the harmless treatment of environmentally harmful p-nitrophenol. This invention provides a novel magnetically supported thioether-chelated nitrogen heterocyclic carbene palladium complex catalyst, MNPs-NHC-Pd, for the Suzuki-Miyaura coupling reaction and the reduction of p-nitrophenol. When used in catalytic reactions, it requires a small amount of catalyst, is reusable, uses a green and harmless reaction solvent, achieves high catalytic yields, is simple to operate, and is easy to separate.

[0033] The catalytic Suzuki-Miyaura coupling reaction is carried out using the following steps: the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd of the present invention, base, phenylboronic acid, and aryl halide are added to water and ethanol (1:1), reacted at 60°C for 10-300 minutes, cooled to room temperature, the catalyst is separated by an external magnet, extracted with ethyl acetate, the organic phases are combined, dried, concentrated, and separated by column chromatography to obtain the pure product.

[0034] The recycling experiment of the MNPs-NHC-Pd catalyzed Suzuki-Miyaura coupling reaction adopted the following steps: The magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd of the present invention, Cs2CO3, phenylboronic acid and p-bromoanisole were reacted in water and ethanol (1:1) at 60°C for 30 minutes. The reaction solution was cooled to room temperature, the catalyst was separated by an external magnet, and the catalyst was washed with water (10 mL × 2) and ethanol (10 mL × 2) in turn before being used to catalyze the next reaction.

[0035] The catalytic reduction of 4-nitrophenol (4-NP) was carried out using the following steps: 4-NP (2.5 mmol / L, 10 mL) and NaBH4 (0.25 mol / L, 10 mL) were mixed evenly, and then the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd of the present invention was added. The reaction was stirred at room temperature, and every 30 seconds, 30 μL of the reaction solution was taken and diluted with distilled water to 3.0 mL. The progress of the catalytic reduction reaction was monitored by detecting the ultraviolet absorption intensity.

[0036] The present invention has the following beneficial effects:

[0037] 1. This invention prepares a thioether-chelated nitrogen heterocyclic carbene palladium complex catalyst (MNPs-NHC-Pd) supported on magnetic nanoparticles. Using amino alcohols as raw materials, an imidazole derivative containing a hydroxyl group on the N-substituent is obtained through a condensation and ring-closing reaction. This derivative undergoes subsequent substitution reactions with thionyl chloride and cyclohexanethiol to obtain an imidazole derivative containing a thioether group on the N-substituent. Further reaction with 1,3-dibromopropane yields an N-bromopropyl-N'-cyclohexane thioether-substituted imidazole bromium salt, which then undergoes a direct metallization reaction with Pd(OAc)₂ or PdCl₂ to obtain the N-bromopropyl-substituted thioether-chelated nitrogen heterocyclic carbene palladium complex NHC-Pd. The structure of the obtained complex is confirmed by HR-MS, NMR, and X-ray single-crystal diffraction. The NHC-Pd complex reacts with amino-functionalized magnetic nanoparticles (MNPs-NH2) to obtain a thioether-chelated nitrogen heterocyclic carbene palladium complex catalyst (MNPs-NHC-Pd) supported on magnetic nanoparticles. This catalyst exhibits the structural stability and excellent catalytic performance of chelated nitrogen heterocyclic carbene palladium complexes, avoiding the disadvantages of difficult separation and recovery, high operating costs, and product contamination associated with chelated nitrogen heterocyclic carbene palladium complexes. Furthermore, the prepared magnetically supported heterogeneous nitrogen heterocyclic carbene palladium catalyst can be separated, recovered, and reused during use using an external magnet.

[0038] 2. The magnetic nanoparticle-supported thioether chelated nitrogen heterocyclic carbene palladium complex catalyst (MNPs-NHC-Pd) prepared in this invention exhibits excellent catalytic performance for the reduction reaction of 4-nitrophenol, playing a crucial role in environmental remediation. The magnetic nanoparticle-supported thioether chelated nitrogen heterocyclic carbene palladium complex catalyst (MNPs-NHC-Pd) prepared in this invention is easily separated in the catalytic C / C bonding reaction, maintains a catalytic yield of 87% even after 10 reactions, and exhibits virtually no morphological change, significantly reducing costs and demonstrating promising application prospects in the field of catalysis. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 The graph shows the cyclic performance of the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd prepared in Example 1 for catalyzing the Suzuki-Miyaura coupling reaction. The reaction conditions were: p-bromoanisole (1 mmol), phenylboronic acid (1.5 mmol), Cs2CO3 (2 mmol), solvent (EtOH:H2O = 1:1, v:v, 3 mL), MNPs-NHC-Pd (8.00 mg, 0.076 mmol% Pd), and temperature 60 °C.

[0041] Figure 2 Scanning electron microscope (SEM) images of the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd prepared in Example 1, wherein (a) is the newly prepared magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd; and (b) is the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd after 10 cycles of use.

[0042] Figure 3 The image shows the effect of the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd catalytic reduction of 4-NP prepared in Example 1. Detailed Implementation

[0043] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0044] Example 1

[0045] The preparation method of a magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex according to this embodiment includes the following steps:

[0046] (1) In a 250 mL three-necked flask, L-phenylalanine (60 mmol, 9.07 g) and ammonium chloride (60 mmol, 3.21 g) were dissolved in 120 mL of methanol. Under ice bath cooling, 36% formaldehyde solution (60 mmol, 4.60 mL) and 40% glyoxal solution (60 mmol, 7.60 mL) were added dropwise using a constant pressure funnel. After the addition was complete, the temperature was raised to 60 °C and the reaction was carried out for 5 h. The reaction solution was then evaporated to dryness to obtain a reddish-brown viscous liquid. The above reddish-brown oily viscous substance was dissolved in 150 mL of NaOH solution (2 M), extracted with dichloromethane (20 mL × 3), the organic phases were combined, dried over anhydrous Na2SO4, filtered, the solvent was removed under reduced pressure, and purified by column chromatography to obtain ( S )-2-(1-imidazolyl)-3-phenylpropanol (9.71 g, 80% yield).

[0047] (2) Add ( ) to a 50 mL round-bottom flask S 2-(1-imidazolyl)-3-phenylpropanol (10 mmol, 2.02 g) and anhydrous sodium carbonate (10 mmol, 1.06 g) were added dropwise, followed by the slow addition of SOCl2 (5.00 mL). After the addition was complete, the mixture was heated to 50 °C and reacted for 4 h. The reaction solution was then evaporated to dryness to obtain a brown viscous liquid. NaOH solution (2.0 M) was added to the above viscous liquid until the pH of the mixture was alkaline. The mixture was extracted with CH2Cl2 (20 mL × 3), the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure to obtain ( S )-1-(1-chloro-3-phenyl-2-propyl)-imidazolium (2.21 g, 99% yield). Yellow oily substance. 1 H NMR (CDCl3, 400 MHz): δ 7.46 (s, 1H), 7.28-7.26 (m, 3H), 7.09-7.00 (m, 4H), 4.49-4.46 (m, 1H), 3.83-3.72 (m, 2H), 3.27 (dd, J 1 = 5.8 Hz J 2 = 13.6 Hz, 1H), 3.11(dd, J 1 = 8 Hz J 2 = 13.6 Hz, 1H) ppm. 13 C NMR (100 MHz, CDCl3): δ 136.5, 135.7,129.5, 128.8, 127.3, 116.8, 60.5, 46.4, 39.3 ppm.

[0048] (3) Add NaOH (30 mmol, 1.20 g) and ethanol (30 mL) to a 100 mL round-bottom flask, heat to 50 °C and stir until the NaOH is completely dissolved. Add cyclohexanethiol (30 mmol, 3.56 mL) to the above NaOH-ethanol solution, and then add ( S 1-(1-chloro-3-phenyl-2-propyl)-imidazolium (10 mmol, 2.21 g) was dissolved in ethanol (10 mL) and slowly added dropwise to the reaction flask. After the addition was complete, the temperature was raised to 70 °C and the reaction was carried out for 6 h. After the reaction was completed, the reaction solution was evaporated to dryness to obtain an orange-yellow viscous substance. Water (30 mL) was added to the above viscous substance, and the mixture was extracted with CH2Cl2 (20 mL × 3). The organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure. The solution was purified by column chromatography to obtain ( S )-1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium (2.91 g, 97% yield). Yellow oily substance. 1 H NMR (CDCl3, 400 MHz): δ 7.34 (s, 1H), 7.25-7.19 (m,3H), 7.05 (s, 1H), 6.98-6.96 (m, 2H), 6.93 (s, 1H), 4.31-4.24 (m,1H), 3.23(dd, J 1 = 5.60 Hz J 2 = 14 Hz, 1H), 3.02 (dd, J 1 = 8.8 Hz J 2= ​​14 Hz, 1H), 2.95-2.85(m, 2H), 2.34-2.28 (m, 1H), 1.89-1.81 (m, 2H), 1.71 (t, J = 3.6 Hz, 2H) 1.58(s, 1H), 1.25-1.18 (m, 5H) ppm. 13 C NMR (100 MHz, CDCl3): δ 136.6, 136.4,129.4, 128.7, 128.5, 126.9, 116.5, 60.6, 44.1, 41.3, 35.1, 33.5, 25.8,25.5ppm. HR-MS (ESI) m / z calcd for C 18 H 25 N2S + (M+H) + 301.1733, found 301.1726.

[0049] (4) Add ( ) to a 50 mL round-bottom flask S 1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium (3.5 mmol, 1.0 g) and 1,3-dibromopropane (3 mL) were heated to 90 °C and reacted for 8 hours. After cooling to room temperature, the resulting brownish-brown viscous solid was collected and purified by column chromatography. N -(1-Cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide (1.40 g, 79% yield). 1 H NMR (CDCl3, 400 MHz): δ 10.62 (s, 1H), 7.49-7.45(d, J = 4Hz, 2H), 7.41-7.21(m, 5H), 4.96-4.86(m, 1H), 4.59-4.49(t, J = 1Hz,2H), 3.50-3.40(m, 2H), 3.34-3.26(t, J = 1Hz, 2H),3.26-3.13(m, 2H), 3.77-3.67(m, 1H), 2.59-2.49(m, 2H), 1.95-1.85(m,2H), 1.79-1.68(m,2H), 1.68-1.57(m,1H),1.42-1.16 (m, 5H) ppm. 13 C NMR (CDCl3, 400MHz): δ 136.9, 135.9, 129.1, 129.0,127.5, 122.3, 121.4, 63.4, 58.2, 48.2, 44.3, 40.4, 34.4, 33.6,33.5, 32.6,29.7, 29.0, 25.6, 18.5. HRMS (ESI) m / z calcd for C 21 H 30 Br2N2S + (M-Br) + 421.13076, found 421.13095.

[0050] (5) In a 50 mL round-bottom flask, N-(1-cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide (1.7 mmol, 0.85 g), palladium acetate (1.7 mmol, 0.40 g), sodium acetate (3.4 mmol, 0.28 g), sodium bromide (6.8 mmol, 0.70 g), and 8 mL of dichloromethane were added and stirred at room temperature for 12 hours under nitrogen protection. After the reaction was completed, the dichloromethane was removed under reduced pressure, and the residue was purified by column chromatography to obtain the N-bromopropyl-substituted thioether chelate nitrogen heterocyclic carbene palladium complex NHC-Pd. 1 H NMR (DMSO, 400 MHz): δ 7.50-7.11(m,7H), 5.14(s, 1H), 4.92-4.68(m, 1H), 4.48-4.03(m, 2H), 4.03(s, 3H), 3.62-3.44(m, 3H), 3.28-3.12(m, 1H),2.87-2.72(m, 1H), 2.03(s, 1H), 1.86(s, 1H), 1.79-1.59(m,2H), 1.59-1.30(m,3H), 1.18(s, 3H). 13 C NMR (DMSO, 400MHz): δ 151.6, 136.9, 129.3, 128.5, 127.9,124.1, 122.2, 61.5, 57.9, 52.2, 51.8, 50.2, 49.1, 34.2, 33.9, 33.4, 31.9,30.8, 25.6, 25.2, 24.7.HR-MS (ESI) m / z calcd for C 21 H 29 Br2N2PdS + (M-Br) + 606.94271, found 606.9379.

[0051] (6) FeCl3 . 6H₂O (4.70 g, 17.38 mmol) and FeCl₂ .1.73 g (8.70 mmol) of 4H₂O was dissolved in 100 mL of distilled water and mechanically stirred at 85 °C for 30 minutes to obtain an orange-yellow suspension. Then, 20 mL of ammonia (25% ammonium hydroxide) was added dropwise until the pH of the system reached 10, resulting in a black suspension. The reaction was continued for another 30 minutes. After the reaction was complete, the suspension was cooled to room temperature, and the product was collected using an external magnet. The product was washed with water until neutral, then washed with ethanol (20 mL × 2), and finally dried under vacuum at 70 °C. The resulting black powder was the hydroxyl-functionalized magnetic nanoparticles MNPs-OH.

[0052] (7) Disperse 3 g of hydroxyl-functionalized magnetic nanoparticles MNPs-OH in a mixed solution of 60 mL of water and ethanol (volume ratio: 1:1), and add 10 mL of 3-aminopropyltriethoxysilane dropwise. Stir the reaction at 70 °C for 24 hours. After the reaction is complete, cool the reaction system to room temperature, collect the product using an external magnet, wash it successively with water (10 mL × 2) and ethanol (10 mL × 2), and then vacuum dry it overnight at 70 °C. The resulting brown powder is the amino-functionalized magnetic nanoparticles MNPs-NH2.

[0053] (8) N-bromopropyl-substituted thioether chelated nitrogen heterocyclic carbene palladium complex NHC-Pd (0.043 mmol, 30 mg) and amino-functionalized magnetic nanoparticles MNPs-NH2 (0.40 g) were heated to 60 °C and stirred for 24 hours in 8 mL of acetonitrile. After the reaction was completed, the reactants were cooled to room temperature, and the product was collected by an external magnet. After washing with water (10 mL × 2) and ethanol (10 mL × 2) successively, the product was dried under vacuum at 70 °C overnight to obtain a brown solid powder, which is the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd.

[0054] Example 2

[0055] This embodiment provides a method for preparing a magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex, the steps of which are as follows:

[0056] (1) In a 250 mL three-necked flask, L-phenylalanine (60 mmol, 9.07 g) and ammonium chloride (60 mmol, 3.21 g) were dissolved in 120 mL of methanol. Under ice bath cooling, 36% formaldehyde solution (60 mmol, 4.60 mL) and 40% glyoxal solution (60 mmol, 7.60 mL) were added dropwise using a constant pressure funnel. After the addition was complete, the temperature was raised to 50 °C and the reaction was carried out for 8 h. The reaction solution was then evaporated to dryness to obtain a reddish-brown viscous liquid. The above reddish-brown oily viscous substance was dissolved in 150 mL of NaOH solution (2 M), extracted with dichloromethane (20 mL × 3), the organic phases were combined, dried over anhydrous Na2SO4, filtered, the solvent was removed under reduced pressure, and purified by column chromatography to obtain ( S )-2-(1-imidazolyl)-3-phenylpropanol (9.22 g, yield 76%).

[0057] (2) Add ( ) to a 50 mL round-bottom flask S 2-(1-imidazolyl)-3-phenylpropanol (10 mmol, 2.02 g) and anhydrous sodium carbonate (10 mmol, 1.06 g) were added dropwise, followed by the slow addition of SOCl2 (5.00 mL). After the addition was complete, the mixture was heated to 70 °C and reacted for 3 h. The reaction solution was then evaporated to dryness to obtain a brown viscous liquid. NaOH solution (2.0 M) was added to the above viscous liquid until the pH of the mixture was alkaline. The mixture was extracted with CH2Cl2 (20 mL × 3), the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure to obtain ( S )-1-(1-chloro-3-phenyl-2-propyl)-imidazolium (2.21 g, 99% yield). Yellow oily substance. 1 H NMR (CDCl3, 400 MHz): δ 7.46 (s, 1H), 7.28-7.26 (m, 3H), 7.09-7.00 (m, 4H), 4.49-4.46 (m, 1H), 3.83-3.72 (m, 2H), 3.27 (dd, J 1 = 5.8 Hz J 2 = 13.6 Hz, 1H), 3.11(dd, J 1 = 8 Hz J 2 = 13.6 Hz, 1H) ppm. 13 C NMR (100 MHz, CDCl3): δ 136.5, 135.7,129.5, 128.8, 127.3, 116.8, 60.5, 46.4, 39.3 ppm.

[0058] (3) Add NaOH (30 mmol, 1.20 g) and ethanol (30 mL) to a 100 mL round-bottom flask, heat to 50 °C and stir until the NaOH is completely dissolved. Add cyclohexanethiol (20 mmol, 2.37 mL) to the above NaOH-ethanol solution, and then add ( S 1-(1-chloro-3-phenyl-2-propyl)-imidazolium (10 mmol, 2.21 g) was dissolved in ethanol (10 mL) and slowly added dropwise to the reaction flask. After the addition was complete, the temperature was raised to 70 °C and the reaction was carried out for 6 h. After the reaction was completed, the reaction solution was evaporated to dryness to obtain an orange-yellow viscous substance. Water (30 mL) was added to the above viscous substance, and the mixture was extracted with CH2Cl2 (20 mL × 3). The organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure. The solution was purified by column chromatography to obtain ( S )-1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium (2.70 g, 90% yield). Yellow oily substance. 1 H NMR (CDCl3, 400 MHz): δ 7.34 (s, 1H), 7.25-7.19 (m, 3H), 7.05 (s, 1H), 6.98-6.96 (m, 2H), 6.93 (s, 1H), 4.31-4.24 (m,1H), 3.23 (dd, J 1 = 5.60 Hz J 2 = 14 Hz, 1H), 3.02 (dd, J 1 = 8.8 Hz J 2= ​​14 Hz, 1H), 2.95-2.85 (m, 2H), 2.34-2.28 (m, 1H), 1.89-1.81 (m, 2H), 1.71 (t, J = 3.6 Hz, 2H) 1.58 (s, 1H),1.25-1.18 (m, 5H) ppm. 13 C NMR (100 MHz, CDCl3): δ 136.6, 136.4, 129.4, 128.7,128.5, 126.9, 116.5, 60.6, 44.1, 41.3, 35.1, 33.5, 25.8, 25.5ppm. HR-MS (ESI)m / z calcd for C 18 H 25 N2S + (M+H) + 301.1733, found 301.1726.

[0059] (4) Add ( ) to a 50 mL round-bottom flask S 1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium (3.5 mmol, 1.05 g) and 1,3-dibromopropane 3.5 mL were added. The mixture was heated to 80 °C and reacted for 12 hours. After cooling to room temperature, the resulting brownish-red viscous solid was collected and purified by column chromatography. N -(1-Cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide (1.29 g, 73% yield). 1 H NMR (CDCl3, 400 MHz): δ 10.62 (s, 1H), 7.49-7.45(d, J = 4Hz, 2H), 7.41-7.21(m, 5H), 4.96-4.86(m, 1H), 4.59-4.49(t, J = 1Hz,2H), 3.50-3.40(m, 2H), 3.34-3.26(t, J = 1Hz, 2H),3.26-3.13(m, 2H), 3.77-3.67(m, 1H), 2.59-2.49(m, 2H), 1.95-1.85(m,2H), 1.79-1.68(m,2H), 1.68-1.57(m,1H),1.42-1.16 (m, 5H) ppm. 13 C NMR (CDCl3, 400MHz): δ 136.9, 135.9, 129.1, 129.0,127.5, 122.3, 121.4, 63.4, 58.2, 48.2, 44.3, 40.4, 34.4, 33.6,33.5, 32.6,29.7, 29.0, 25.6, 18.5. HRMS (ESI) m / z calcd for C 21 H 30 Br2N2S + (M-Br) + 421.13076, found 421.13095.

[0060] (5) In a 50 mL round-bottom flask, add N-(1-cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide (1.7 mmol, 0.85 g), palladium chloride (1.7 mmol, 0.30 g), sodium tert-butoxide (3.4 mmol, 0.33 g), sodium bromide (6.8 mmol, 0.70 g), and 8 mL of toluene. Stir at room temperature for 8 hours under nitrogen protection. After the reaction is complete, remove toluene under reduced pressure, and purify the residue by column chromatography to obtain the N-bromopropyl-substituted thioether chelate nitrogen heterocyclic carbene palladium complex NHC-Pd. 1 H NMR (DMSO, 400 MHz): δ 7.50-7.11(m,7H), 5.14(s, 1H), 4.92-4.68(m,1H), 4.48-4.03(m, 2H), 4.03(s, 3H), 3.62-3.44(m, 3H), 3.28-3.12(m, 1H), 2.87-2.72(m, 1H), 2.03(s, 1H), 1.86(s, 1H), 1.79-1.59(m,2H), 1.59-1.30(m, 3H),1.18(s, 3H). 13 C NMR (DMSO, 400MHz): δ 151.6, 136.9, 129.3, 128.5, 127.9,124.1, 122.2, 61.5, 57.9, 52.2, 51.8, 50.2, 49.1, 34.2, 33.9, 33.4, 31.9,30.8, 25.6, 25.2, 24.7.HR-MS (ESI) m / z calcd for C 21 H 29 Br2N2PdS + (M-Br) + 606.94271, found 606.9379.

[0061] (6) FeCl3 . 6H₂O (4.70 g, 17.38 mmol) and FeCl₂ .1.73 g (8.70 mmol) of 4H₂O was dissolved in 100 mL of distilled water and mechanically stirred at 85 °C for 30 minutes to obtain an orange-yellow suspension. Then, 20 mL of ammonia (25% ammonium hydroxide) was added dropwise until the pH of the system reached 10, resulting in a black suspension. The reaction was continued for another 30 minutes. After the reaction was complete, the suspension was cooled to room temperature, and the product was collected using an external magnet. The product was washed with water until neutral, then washed with ethanol (20 mL * 2), and finally dried under vacuum at 70 °C. The resulting black powder was the hydroxyl-functionalized magnetic nanoparticles MNPs-OH.

[0062] (7) Disperse 3g of hydroxyl-functionalized magnetic nanoparticles MNPs-OH in a mixed solution of 60mL water and ethanol (volume ratio: 1:1), and add 10mL of 3-aminopropyltriethoxysilane dropwise. Stir the reaction at 70℃ for 24 hours. After the reaction is complete, cool the reaction system to room temperature, collect the product using an external magnet, wash it with water (10mL*2) and ethanol (10mL*2) in sequence, and then vacuum dry it overnight at 70℃. The resulting brown powder is the amino-functionalized magnetic nanoparticles MNPs-NH2.

[0063] (8) N-bromopropyl-substituted thioether chelated nitrogen heterocyclic carbene palladium complex NHC-Pd (0.043 mmol, 30 mg) and amino-functionalized magnetic nanoparticles MNPs-NH2 (0.40 g) were heated to 100 °C and stirred for 18 hours in 8 mL of tetrahydrofuran. After the reaction was completed, the reactants were cooled to room temperature, and the product was collected by an external magnet. After washing with water (10 mL × 2) and ethanol (10 mL × 2) successively, the product was dried under vacuum at 70 °C overnight to obtain a brown solid powder, which is the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd.

[0064] Example 3

[0065] This embodiment provides a method for preparing a magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex, the steps of which are as follows:

[0066] (1) In a 250 mL three-necked flask, L-phenylalanine (60 mmol, 9.07 g) and ammonium chloride (60 mmol, 3.21 g) were dissolved in 120 mL of methanol. Under ice bath cooling, 36% formaldehyde solution (60 mmol, 4.60 mL) and 40% glyoxal solution (60 mmol, 7.60 mL) were added dropwise using a constant pressure funnel. After the addition was complete, the temperature was raised to 70 °C and the reaction was carried out for 4 h. The reaction solution was then evaporated to dryness to obtain a reddish-brown viscous liquid. The above reddish-brown oily viscous substance was dissolved in 150 mL of NaOH solution (2 M), extracted with dichloromethane (20 mL × 3), the organic phases were combined, dried over anhydrous Na2SO4, filtered, the solvent was removed under reduced pressure, and purified by column chromatography to obtain ( S )-2-(1-imidazolyl)-3-phenylpropanol (9.10 g, yield 75%).

[0067] (2) Add ( ) to a 50 mL round-bottom flask S 2-(1-imidazolyl)-3-phenylpropanol (10 mmol, 2.02 g) and anhydrous sodium carbonate (10 mmol, 1.06 g) were added dropwise, followed by the slow addition of SOCl2 (10.00 mL). After the addition was complete, the mixture was heated to 60 °C and reacted for 6 h. The reaction solution was then evaporated to dryness to obtain a brown viscous liquid. NaOH solution (2.0 M) was added to the above viscous liquid until the pH of the mixture was alkaline. The mixture was extracted with CH2Cl2 (20 mL × 3), the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure to obtain ( S )-1-(1-chloro-3-phenyl-2-propyl)-imidazolium (2.21 g, 99% yield). Yellow oily substance. 1 H NMR (CDCl3, 400 MHz): δ 7.46 (s, 1H), 7.28-7.26 (m, 3H), 7.09-7.00 (m, 4H), 4.49-4.46 (m, 1H), 3.83-3.72 (m, 2H), 3.27 (dd, J 1 = 5.8 Hz J 2 = 13.6 Hz, 1H), 3.11(dd, J 1 = 8 Hz J 2 = 13.6 Hz, 1H) ppm. 13 C NMR (100 MHz, CDCl3): δ 136.5, 135.7,129.5, 128.8, 127.3, 116.8, 60.5, 46.4, 39.3 ppm.

[0068] (3) Add NaOH (30 mmol, 1.20 g) and ethanol (30 mL) to a 100 mL round-bottom flask, heat to 50 °C and stir until the NaOH is completely dissolved. Add cyclohexanethiol (30 mmol, 3.56 mL) to the above NaOH-ethanol solution, and then add ( S 1-(1-chloro-3-phenyl-2-propyl)-imidazolium (10 mmol, 2.21 g) was dissolved in ethanol (10 mL) and slowly added dropwise to the reaction flask. After the addition was complete, the temperature was raised to 70 °C and the reaction was carried out for 6 h. After the reaction was completed, the reaction solution was evaporated to dryness to obtain an orange-yellow viscous substance. Water (30 mL) was added to the above viscous substance, and the mixture was extracted with CH2Cl2 (20 mL × 3). The organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure. The solution was purified by column chromatography to obtain ( S )-1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium (2.91 g, 97% yield). Yellow oily substance. 1 H NMR (CDCl3, 400 MHz): δ 7.34 (s, 1H), 7.25-7.19 (m,3H), 7.05 (s, 1H), 6.98-6.96 (m, 2H), 6.93 (s, 1H), 4.31-4.24 (m,1H), 3.23(dd, J 1 = 5.60 Hz J 2 = 14 Hz, 1H), 3.02 (dd, J 1 = 8.8 Hz J 2= ​​14 Hz, 1H), 2.95-2.85(m, 2H), 2.34-2.28 (m, 1H), 1.89-1.81 (m, 2H), 1.71 (t, J = 3.6 Hz, 2H) 1.58(s, 1H), 1.25-1.18 (m, 5H) ppm. 13 C NMR (100 MHz, CDCl3): δ 136.6, 136.4,129.4, 128.7, 128.5, 126.9, 116.5, 60.6, 44.1, 41.3, 35.1, 33.5, 25.8,25.5ppm. HR-MS (ESI) m / z calcd for C 18 H 25 N2S + (M+H) + 301.1733, found 301.1726.

[0069] (4) Add ( ) to a 50 mL round-bottom flask S 1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium (4.5 mmol, 1.35 g) and 1,3-dibromopropane (3 mL) were heated to 120 °C and reacted for 6 hours. After cooling to room temperature, the resulting brownish-brown viscous solid was collected and purified by column chromatography. N -(1-Cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide (1.58 g, 70% yield). 1 H NMR (CDCl3, 400 MHz): δ 10.62 (s, 1H), 7.49-7.45(d, J = 4Hz, 2H), 7.41-7.21(m, 5H), 4.96-4.86(m, 1H), 4.59-4.49(t, J = 1Hz,2H), 3.50-3.40(m, 2H), 3.34-3.26(t, J = 1Hz, 2H),3.26-3.13(m, 2H), 3.77-3.67(m, 1H), 2.59-2.49(m, 2H), 1.95-1.85(m,2H), 1.79-1.68(m,2H), 1.68-1.57(m,1H),1.42-1.16 (m, 5H) ppm. 13 C NMR (CDCl3, 400MHz): δ 136.9, 135.9, 129.1, 129.0,127.5, 122.3, 121.4, 63.4, 58.2, 48.2, 44.3, 40.4, 34.4, 33.6,33.5, 32.6,29.7, 29.0, 25.6, 18.5. HRMS (ESI) m / z calcd for C 21 H 30 Br2N2S + (M-Br) + 421.13076, found 421.13095.

[0070] (5) In a 50 mL round-bottom flask, add N-(1-cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide (1.7 mmol, 0.85 g), palladium acetate (1.7 mmol, 0.40 g), sodium tert-amyl alcohol (3.4 mmol, 0.37 g), sodium bromide (6.8 mmol, 0.70 g), and 8 mL of 1,4-dioxane. Stir at room temperature for 12 hours under nitrogen protection. After the reaction is complete, remove 1,4-dioxane under reduced pressure. The residue is purified by column chromatography to obtain the N-bromopropyl-substituted thioether chelate nitrogen heterocyclic carbene palladium complex NHC-Pd.

[0071] (6) FeCl3 . 6H₂O (4.70 g, 17.38 mmol) and FeCl₂ . 1.73 g (8.70 mmol) of 4H₂O was dissolved in 100 mL of distilled water and mechanically stirred at 85 °C for 30 minutes to obtain an orange-yellow suspension. Then, 20 mL of ammonia (25% ammonium hydroxide) was added dropwise until the pH of the system reached 10, resulting in a black suspension. The reaction was continued for another 30 minutes. After the reaction was complete, the suspension was cooled to room temperature, and the product was collected using an external magnet. The product was washed with water until neutral, then washed with ethanol (20 mL * 2), and finally dried under vacuum at 70 °C. The resulting black powder was the hydroxyl-functionalized magnetic nanoparticles MNPs-OH.

[0072] (7) 3 g of hydroxyl-functionalized magnetic nanoparticles MNPs-OH were dispersed in a mixed solution of 60 mL of water and ethanol (volume ratio: 1:1). 10 mL of 3-aminopropyltriethoxysilane was added dropwise and the mixture was stirred at 70 °C for 24 hours. After the reaction was completed, the reaction system was cooled to room temperature, and the product was collected by an external magnet. After washing with water (10 mL*2) and ethanol (10 mL*2) in sequence, the product was dried under vacuum at 70 °C overnight. The resulting brown powder was the amino-functionalized magnetic nanoparticles MNPs-NH2. (8) N-bromopropyl-substituted thioether chelate nitrogen heterocyclic carbene palladium complex NHC-Pd (0.043 mmol, 30 mg) and amino-functionalized magnetic nanoparticles MNPs-NH2 (0.40 g) were heated to 20 °C and stirred in 8 mL of tetrahydrofuran for 20 hours. After the reaction was completed, the reactants were cooled to room temperature, and the product was collected by an external magnet. After washing with water (10 mL × 2) and ethanol (10 mL × 2) in sequence, the product was dried under vacuum at 70 °C overnight to obtain a brown solid powder, which is the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd.

[0073] Example 4

[0074] This embodiment provides a method for preparing a magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex, the steps of which are as follows:

[0075] (1) In a 250 mL three-necked flask, L-phenylalanine (60 mmol, 9.07 g) and ammonium chloride (60 mmol, 3.21 g) were dissolved in 120 mL of methanol. Under ice bath cooling, 36% formaldehyde solution (60 mmol, 4.60 mL) and 40% glyoxal solution (60 mmol, 7.60 mL) were added dropwise using a constant pressure funnel. After the addition was complete, the temperature was raised to 55 °C and the reaction was carried out for 7 h. The reaction solution was then evaporated to dryness to obtain a reddish-brown viscous liquid. The above reddish-brown oily viscous substance was dissolved in 150 mL of NaOH solution (2 M), extracted with dichloromethane (20 mL × 3), the organic phases were combined, dried over anhydrous Na2SO4, filtered, the solvent was removed under reduced pressure, and purified by column chromatography to obtain ( S )-2-(1-imidazolyl)-3-phenylpropanol (9.95 g, yield 82%).

[0076] (2) Add ( ) to a 50 mL round-bottom flask S 2-(1-imidazolyl)-3-phenylpropanol (10 mmol, 2.02 g) and anhydrous sodium carbonate (10 mmol, 1.06 g) were added dropwise, followed by the slow addition of SOCl2 (5.00 mL). After the addition was complete, the mixture was heated to 50 °C and reacted for 4 h. The reaction solution was then evaporated to dryness to obtain a brown viscous liquid. NaOH solution (2.0 M) was added to the above viscous liquid until the pH of the mixture was alkaline. The mixture was extracted with CH2Cl2 (20 mL × 3), the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure to obtain ( S )-1-(1-chloro-3-phenyl-2-propyl)-imidazolium (2.21 g, 99% yield). Yellow oily substance. 1 H NMR (CDCl3, 400 MHz): δ 7.46 (s, 1H), 7.28-7.26 (m, 3H), 7.09-7.00 (m, 4H), 4.49-4.46 (m, 1H), 3.83-3.72 (m, 2H), 3.27 (dd, J 1 = 5.8 Hz J 2 = 13.6 Hz, 1H), 3.11(dd, J 1 = 8 Hz J 2 = 13.6 Hz, 1H) ppm. 13C NMR (100 MHz, CDCl3): δ 136.5, 135.7,129.5, 128.8, 127.3, 116.8, 60.5, 46.4, 39.3 ppm.

[0077] (3) Add NaOH (30 mmol, 1.20 g) and ethanol (30 mL) to a 100 mL round-bottom flask, heat to 50 °C and stir until the NaOH is completely dissolved. Add cyclohexanethiol (25 mmol, 2.97 mL) to the above NaOH-ethanol solution, and then add ( S 1-(1-chloro-3-phenyl-2-propyl)-imidazolium (10 mmol, 2.21 g) was dissolved in ethanol (10 mL) and slowly added dropwise to the reaction flask. After the addition was complete, the temperature was raised to 55 °C and the reaction was carried out for 4 h. After the reaction was completed, the reaction solution was evaporated to dryness to obtain an orange-yellow viscous substance. Water (30 mL) was added to the above viscous substance, and the mixture was extracted with CH2Cl2 (20 mL × 3). The organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure. The solution was purified by column chromatography to obtain ( S )-1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium (2.85 g, 95% yield). Yellow oily substance. 1 H NMR (CDCl3, 400 MHz): δ 7.34 (s, 1H), 7.25-7.19 (m,3H), 7.05 (s, 1H), 6.98-6.96 (m, 2H), 6.93 (s, 1H), 4.31-4.24 (m,1H), 3.23(dd, J 1 = 5.60 Hz J 2 = 14 Hz, 1H), 3.02 (dd, J 1 = 8.8 Hz J 2= ​​14 Hz, 1H), 2.95-2.85(m, 2H), 2.34-2.28 (m, 1H), 1.89-1.81 (m, 2H), 1.71 (t, J = 3.6 Hz, 2H) 1.58(s, 1H), 1.25-1.18 (m, 5H) ppm. 13C NMR (100 MHz, CDCl3): δ 136.6, 136.4,129.4, 128.7, 128.5, 126.9, 116.5, 60.6, 44.1, 41.3, 35.1, 33.5, 25.8,25.5ppm. HR-MS (ESI) m / z calcd for C 18 H 25 N2S + (M+H) + 301.1733, found 301.1726.

[0078] (4) Add ( ) to a 50 mL round-bottom flask S 1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium (3.0 mmol, 0.90 g) and 1,3-dibromopropane 3 mL were heated to 100 °C and reacted for 8 hours. After cooling to room temperature, the resulting brownish-brown viscous solid was collected and purified by column chromatography. N -(1-Cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide (1.12 g, 74% yield). 1 H NMR (CDCl3, 400 MHz): δ 10.62 (s, 1H), 7.49-7.45(d, J = 4Hz, 2H), 7.41-7.21(m, 5H), 4.96-4.86(m, 1H), 4.59-4.49(t, J = 1Hz,2H), 3.50-3.40(m, 2H), 3.34-3.26(t, J = 1Hz, 2H),3.26-3.13(m, 2H), 3.77-3.67(m, 1H), 2.59-2.49(m, 2H), 1.95-1.85(m,2H), 1.79-1.68(m,2H), 1.68-1.57(m,1H),1.42-1.16 (m, 5H) ppm. 13 C NMR (CDCl3, 400MHz): δ 136.9, 135.9, 129.1, 129.0,127.5, 122.3, 121.4, 63.4, 58.2, 48.2, 44.3, 40.4, 34.4, 33.6,33.5, 32.6,29.7, 29.0, 25.6, 18.5. HRMS (ESI) m / z calcd for C 21 H 30 Br2N2S+ (M-Br) + 421.13076, found 421.13095.

[0079] (5) In a 50 mL round-bottom flask, add N-(1-cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide (1.7 mmol, 0.85 g), palladium acetate (1.7 mmol, 0.40 g), sodium tert-amyloxide (3.4 mmol, 0.37 g), sodium bromide (6.8 mmol, 0.70 g), and 8 mL of dimethyl sulfoxide. Stir at room temperature for 8 hours under nitrogen protection. After the reaction is complete, remove dimethyl sulfoxide under reduced pressure, and purify the residue by column chromatography to obtain the N-bromopropyl-substituted thioether chelate nitrogen heterocyclic carbene palladium complex NHC-Pd.

[0080] (6) FeCl3 . 6H₂O (4.70 g, 17.38 mmol) and FeCl₂ . 1.73 g (8.70 mmol) of 4H₂O was dissolved in 100 mL of distilled water and mechanically stirred at 85 °C for 30 minutes to obtain an orange-yellow suspension. Then, 20 mL of ammonia (25% ammonium hydroxide) was added dropwise until the pH of the system reached 10, resulting in a black suspension. The reaction was continued for another 30 minutes. After the reaction was complete, the suspension was cooled to room temperature, and the product was collected using an external magnet. The product was washed with water until neutral, then washed with ethanol (20 mL * 2), and finally dried under vacuum at 70 °C. The resulting black powder was the hydroxyl-functionalized magnetic nanoparticles MNPs-OH.

[0081] (7) Disperse 3g of hydroxyl-functionalized magnetic nanoparticles MNPs-OH in a mixed solution of 60mL water and ethanol (volume ratio: 1:1), and add 10mL of 3-aminopropyltriethoxysilane dropwise. Stir the reaction at 70℃ for 24 hours. After the reaction is complete, cool the reaction system to room temperature, collect the product using an external magnet, wash it with water (10mL*2) and ethanol (10mL*2) in sequence, and then vacuum dry it overnight at 70℃. The resulting brown powder is the amino-functionalized magnetic nanoparticles MNPs-NH2.

[0082] (8) N-bromopropyl-substituted thioether chelated nitrogen heterocyclic carbene palladium complex NHC-Pd (0.043 mmol, 30 mg) and amino-functionalized magnetic nanoparticles MNPs-NH2 (0.40 g) were heated to 80 °C and stirred for 20 hours in 8 mL of toluene. After the reaction was completed, the reactants were cooled to room temperature, and the product was collected by an external magnet. After washing with water (10 mL*2) and ethanol (10 mL*2) successively, the product was dried under vacuum at 70 °C overnight to obtain a brown solid powder, which is the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd.

[0083] Example 5

[0084] This embodiment provides a method for preparing a magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex, the steps of which are as follows:

[0085] (1) In a 250 mL three-necked flask, L-phenylalanine (60 mmol, 9.07 g) and ammonium chloride (60 mmol, 3.21 g) were dissolved in 120 mL of methanol. Under ice bath cooling, 36% formaldehyde solution (60 mmol, 4.60 mL) and 40% glyoxal solution (60 mmol, 7.60 mL) were added dropwise using a constant pressure funnel. After the addition was complete, the temperature was raised to 60 °C and the reaction was carried out for 5 h. The reaction solution was then evaporated to dryness to obtain a reddish-brown viscous liquid. The above reddish-brown oily viscous substance was dissolved in 150 mL of NaOH solution (2 M), extracted with dichloromethane (20 mL × 3), the organic phases were combined, dried over anhydrous Na2SO4, filtered, the solvent was removed under reduced pressure, and purified by column chromatography to obtain ( S )-2-(1-imidazolyl)-3-phenylpropanol (9.71 g, 80% yield).

[0086] (2) Add ( ) to a 50 mL round-bottom flask S 2-(1-imidazolyl)-3-phenylpropanol (10 mmol, 2.02 g) and anhydrous sodium carbonate (10 mmol, 1.06 g) were added dropwise, followed by the slow addition of SOCl2 (5.00 mL). After the addition was complete, the mixture was heated to 50 °C and reacted for 4 h. The reaction solution was then evaporated to dryness to obtain a brown viscous liquid. NaOH solution (2.0 M) was added to the above viscous liquid until the pH of the mixture was alkaline. The mixture was extracted with CH2Cl2 (20 mL × 3), the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure to obtain ( S )-1-(1-chloro-3-phenyl-2-propyl)-imidazolium (2.21 g, 99% yield). Yellow oily substance. 1H NMR (CDCl3, 400 MHz): δ 7.46 (s, 1H), 7.28-7.26 (m, 3H), 7.09-7.00 (m, 4H), 4.49-4.46 (m, 1H), 3.83-3.72 (m, 2H), 3.27 (dd, J 1 = 5.8 Hz J 2 = 13.6 Hz, 1H), 3.11(dd, J 1 = 8 Hz J 2 = 13.6 Hz, 1H) ppm. 13 C NMR (100 MHz, CDCl3): δ 136.5, 135.7,129.5, 128.8, 127.3, 116.8, 60.5, 46.4, 39.3 ppm.

[0087] (3) Add NaOH (30 mmol, 1.20 g) and ethanol (30 mL) to a 100 mL round-bottom flask, heat to 50 °C and stir until the NaOH is completely dissolved. Add cyclohexanethiol (30 mmol, 3.56 mL) to the above NaOH-ethanol solution, and then add ( S 1-(1-chloro-3-phenyl-2-propyl)-imidazolium (10 mmol, 2.21 g) was dissolved in ethanol (10 mL) and slowly added dropwise to the reaction flask. After the addition was complete, the temperature was raised to 70 °C and the reaction was carried out for 6 h. After the reaction was completed, the reaction solution was evaporated to dryness to obtain an orange-yellow viscous substance. Water (30 mL) was added to the above viscous substance, and the mixture was extracted with CH2Cl2 (20 mL × 3). The organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure. The solution was purified by column chromatography to obtain ( S )-1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium (2.91 g, 97% yield). Yellow oily substance. 1 H NMR (CDCl3, 400 MHz): δ 7.34 (s, 1H), 7.25-7.19 (m,3H), 7.05 (s, 1H), 6.98-6.96 (m, 2H), 6.93 (s, 1H), 4.31-4.24 (m,1H), 3.23(dd, J 1 = 5.60 Hz J 2 = 14 Hz, 1H), 3.02 (dd, J 1 = 8.8 Hz J2= ​​14 Hz, 1H), 2.95-2.85(m, 2H), 2.34-2.28 (m, 1H), 1.89-1.81 (m, 2H), 1.71 (t, J = 3.6 Hz, 2H) 1.58(s, 1H), 1.25-1.18 (m, 5H) ppm. 13 C NMR (100 MHz, CDCl3): δ 136.6, 136.4,129.4, 128.7, 128.5, 126.9, 116.5, 60.6, 44.1, 41.3, 35.1, 33.5, 25.8,25.5ppm. HR-MS (ESI) m / z calcd for C 18 H 25 N2S + (M+H) + 301.1733, found 301.1726.

[0088] (4) Add ( ) to a 50 mL round-bottom flask S 1-(1-cyclohexylmercapto-3-phenyl-2-propyl)-imidazolium (3.5 mmol, 1.05 g) and 1,3-dibromopropane 3 mL were heated to 90 °C and reacted for 8 hours. After cooling to room temperature, the resulting brownish-brown viscous solid was collected and purified by column chromatography. N -(1-Cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide (1.40 g, 79% yield). 1 H NMR (CDCl3, 400 MHz): δ 10.62 (s, 1H), 7.49-7.45(d, J = 4Hz, 2H), 7.41-7.21(m, 5H), 4.96-4.86(m, 1H), 4.59-4.49(t, J = 1Hz,2H), 3.50-3.40(m, 2H), 3.34-3.26(t, J = 1Hz, 2H),3.26-3.13(m, 2H), 3.77-3.67(m, 1H), 2.59-2.49(m, 2H), 1.95-1.85(m,2H), 1.79-1.68(m,2H), 1.68-1.57(m,1H),1.42-1.16 (m, 5H) ppm. 13C NMR (CDCl3, 400MHz): δ 136.9, 135.9, 129.1, 129.0,127.5, 122.3, 121.4, 63.4, 58.2, 48.2, 44.3, 40.4, 34.4, 33.6,33.5, 32.6,29.7, 29.0, 25.6, 18.5. HRMS (ESI) m / z calcd for C 21 H 30 Br2N2S + (M-Br) + 421.13076, found 421.13095.

[0089] (5) In a 50 mL round-bottom flask, add N-(1-cyclohexylmercapto-3-phenyl-2-propyl)-N'-(3-bromopropyl)-imidazolium bromide (1.7 mmol, 0.85 g), palladium chloride (1.7 mmol, 0.30 g), potassium tert-amyloxide (3.4 mmol, 0.43 g), sodium bromide (6.8 mmol, 0.70 g), and 8 mL of dimethylformamide. Stir at room temperature for 12 hours under nitrogen protection. After the reaction is complete, remove dimethylformamide under reduced pressure, and purify the residue by column chromatography to obtain the N-bromopropyl-substituted thioether chelate nitrogen heterocyclic carbene palladium complex NHC-Pd.

[0090] (6) FeCl3 . 6H₂O (4.70 g, 17.38 mmol) and FeCl₂ . 1.73 g (8.70 mmol) of 4H₂O was dissolved in 100 mL of distilled water and mechanically stirred at 85 °C for 30 minutes to obtain an orange-yellow suspension. Then, 20 mL of ammonia (25% ammonium hydroxide) was added dropwise until the pH of the system reached 10, resulting in a black suspension. The reaction was continued for another 30 minutes. After the reaction was complete, the suspension was cooled to room temperature, and the product was collected using an external magnet. The product was washed with water until neutral, then washed with ethanol (20 mL * 2), and finally dried under vacuum at 70 °C. The resulting black powder was the hydroxyl-functionalized magnetic nanoparticles MNPs-OH.

[0091] (7) Disperse 3g of hydroxyl-functionalized magnetic nanoparticles MNPs-OH in a mixed solution of 60mL water and ethanol (volume ratio: 1:1), and add 10mL of 3-aminopropyltriethoxysilane dropwise. Stir the reaction at 70℃ for 24 hours. After the reaction is complete, cool the reaction system to room temperature, collect the product using an external magnet, wash it with water (10mL*2) and ethanol (10mL*2) in sequence, and then vacuum dry it overnight at 70℃. The resulting brown powder is the amino-functionalized magnetic nanoparticles MNPs-NH2.

[0092] (8) N-bromopropyl-substituted thioether chelated nitrogen heterocyclic carbene palladium complex NHC-Pd (0.043 mmol, 30 mg) and amino-functionalized magnetic nanoparticles MNPs-NH2 (0.40 g) were heated to 60 °C and stirred for 24 hours in 8 mL of 1,4-dioxane. After the reaction was completed, the reactants were cooled to room temperature, and the product was collected by an external magnet. After washing with water (10 mL*2) and ethanol (10 mL*2) successively, the product was dried under vacuum at 70 °C overnight to obtain a brown solid powder, which is the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd.

[0093] Application Example 1

[0094] The magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd prepared in Example 1 was used as a catalyst as follows:

[0095] Examples of some CC Suzuki coupling catalytic reactions:

[0096] Aryl halides (1.0 mmol), phenylboronic acid (1.5 mmol), base (2.0 mmol), and magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd (4.00 mg, 0.038 mmol% Pd) were added to a mixture of 3 mL of water and ethanol (volume ratio 1:1). The mixture was reacted at 60 °C for 10–300 min, cooled to room temperature, and the coupling product was extracted with ethyl acetate (5 mL × 3). The organic phases were combined, dried, concentrated, and separated by column chromatography to obtain the pure product.

[0097] The partial catalytic results are shown in the table below:

[0098]

[0099]

[0100] a. Reaction conditions: aryl bromide (1 mmol), phenylboronic acid (1.5 mmol), Cs2CO3 base (2 mmol), solvent 3 mL (EtOH:H2O, volume ratio = 1:1), MNPs-NHC-Pd (4.00 mg, 0.038 mmol% Pd), temperature 60℃.

[0101] b. Reaction conditions: chlorobenzene (1 mmol), phenylboronic acid (1.5 mmol), Cs2CO3 base (2 mmol), solvent 3 mL (EtOH:H2O, volume ratio = 1:1), MNPs-NHC-Pd (4.00 mg, 0.038 mmol% Pd), temperature 80℃.

[0102] The following is an experiment on the cyclic use of MNPs-NHC-Pd:

[0103] The recyclability of the magnetically supported thioether-chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd was investigated via a Suzuki-Miyaura coupling reaction of phenylboronic acid and p-bromoanisole. After reacting at 60°C for 30 minutes, as shown... Figure 1 As shown, MNPs-NHC-Pd still achieves an 88% catalytic yield even after 10 cycles. Figure 2 As shown, the morphology of MNPs-NHC-Pd remained essentially unchanged before and after 10 reactions.

[0104] An aqueous solution of 4-NP (2.5 mmol / L, 10 mL) is pale yellow, with maximum absorption at 315 nm. When NaBH4 (0.25 mol / L, 10 mL) is added to the 4-NP aqueous solution, the solution turns dark yellow due to the formation of 4-nitrophenol oxide ions, and the absorbance shifts to 399 nm. The reaction begins upon the addition of MNPs-NHC-Pd (6.00 mg, 0.057 mmol% Pd). The reaction process is monitored by detecting the decrease in the absorption peak intensity corresponding to the 4-nitrophenol oxide ion and the increase in the absorption peak intensity at 296 nm corresponding to 4-AP. Figure 3 ).

[0105] The above data demonstrate that the synthesized magnetically supported thioether-chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd exhibits excellent catalytic effects on both the Suzuki-Miyaura coupling reaction and the reduction of 4-nitrophenol. Suzuki-Miyaura coupling plays a crucial role in organic synthesis, drug development, and the development of functional materials, while the reduction of 4-nitrophenol is vital for environmental remediation. Therefore, the magnetically supported thioether-chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd synthesized in this invention shows great promise for future applications.

[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd, with the following structural formula: ； Prepared using the following steps: (1) L-phenylpropanol, ammonium chloride, formaldehyde and glyoxal were dissolved in methanol and heated to obtain an imidazole derivative with hydroxyl groups on the N-substituent. Then, thionyl chloride was heated and refluxed under the catalysis of anhydrous sodium carbonate to obtain an imidazole derivative with chlorine on the N-substituent. (2) The imidazole derivative with chlorine on the N-substituent in step (1) reacts with cyclohexanethiol in ethanol under alkaline catalysis and under heating and reflux to obtain the imidazole derivative with cyclohexanethioether on the N-substituent. (3) The imidazole derivative containing cyclohexyl sulfide on the N-substituent of step (2) is heated and refluxed with 1,3-dibromopropane to obtain N-bromopropyl-N'-cyclohexyl sulfide-substituted imidazole bromide salt. (4) The N-bromopropyl-N'-cyclohexyl sulfide-substituted imidazolium bromide salt and palladium salt from step (3) were reacted in organic solvent I in the presence of alkaline substances and sodium bromide at room temperature, the solvent was removed, and the N-bromopropyl-substituted sulfide chelated nitrogen heterocyclic carbene palladium complex NHC-Pd was obtained by column chromatography. (5) The N-bromopropyl-substituted thioether chelated nitrogen heterocyclic carbene palladium complex NHC-Pd from step (4) and amino-functionalized magnetic nanoparticles were placed in organic solvent II. After stirring and reacting, magnetic separation was performed to obtain the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd. The preparation steps of the amino-functionalized magnetic nanoparticles are as follows: FeCl3 . 6H2O and FeCl2 . 4H2O was dissolved in water, heated and stirred to obtain an orange-yellow suspension, and then ammonia was added dropwise to obtain a black suspension. After the reaction was cooled, the product was collected, washed with water and ethanol and dried to obtain hydroxyl-functionalized magnetic nanoparticles MNPs-OH. The hydroxyl-functionalized magnetic nanoparticles MNPs-OH were dispersed in an ethanol aqueous solution, and 3-aminopropyltriethoxysilane was added dropwise to react. After cooling, the product was washed with water and ethanol and dried to obtain amino-functionalized magnetic nanoparticles MNPs-NH2.

2. The method for preparing the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd according to claim 1, characterized in that, The following steps are required: (1) L-phenylpropanol, ammonium chloride, formaldehyde and glyoxal were dissolved in methanol and heated to obtain an imidazole derivative with hydroxyl groups on the N-substituent. Then, thionyl chloride was heated and refluxed under the catalysis of anhydrous sodium carbonate to obtain an imidazole derivative with chlorine on the N-substituent. (2) The imidazole derivative with chlorine on the N-substituent in step (1) reacts with cyclohexanethiol in ethanol under alkaline catalysis and under heating and reflux to obtain the imidazole derivative with cyclohexanethioether on the N-substituent. (3) The imidazole derivative containing cyclohexyl sulfide on the N-substituent of step (2) is heated and refluxed with 1,3-dibromopropane to obtain N-bromopropyl-N'-cyclohexyl sulfide-substituted imidazole bromide salt. (4) The N-bromopropyl-N'-cyclohexyl sulfide-substituted imidazolium bromide salt and palladium salt from step (3) were reacted in organic solvent I in the presence of alkaline substances and sodium bromide at room temperature, the solvent was removed, and the N-bromopropyl-substituted sulfide chelated nitrogen heterocyclic carbene palladium complex NHC-Pd was obtained by column chromatography. (5) The N-bromopropyl-substituted thioether chelated nitrogen heterocyclic carbene palladium complex NHC-Pd from step (4) was placed in organic solvent II and stirred. After the reaction, the thioether chelated nitrogen heterocyclic carbene palladium compound MNPs-NHC-Pd immobilized on the magnetic nanoparticles was obtained by magnetic separation. The preparation steps of the amino-functionalized magnetic nanoparticles are as follows: FeCl3 . 6H2O and FeCl2 . 4H2O was dissolved in water, heated and stirred to obtain an orange-yellow suspension, and then ammonia was added dropwise to obtain a black suspension. After the reaction was cooled, the product was collected, washed with water and ethanol and dried to obtain hydroxyl-functionalized magnetic nanoparticles MNPs-OH. The hydroxyl-functionalized magnetic nanoparticles MNPs-OH were dispersed in an ethanol aqueous solution, and 3-aminopropyltriethoxysilane was added dropwise to react. After cooling, the product was washed with water and ethanol and dried to obtain amino-functionalized magnetic nanoparticles MNPs-NH2.

3. The method for preparing the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd according to claim 2, characterized in that: In step (1), the molar ratio of L-phenylpropanol, ammonium chloride, formaldehyde, and glyoxal is 1:1:1:1, with the formaldehyde concentration being 36% and the glyoxal concentration being 40%. The heating reaction conditions are a temperature of 50-70℃ and a time of 4-8h. The concentration of the imidazole derivative containing a hydroxyl group on the N-substituent in thionyl chloride is 1-2mol / L, and the heating reflux reaction conditions are a temperature of 50-70℃ and a time of 3-5h.

4. The method for preparing the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd according to claim 3, characterized in that: In step (2), the molar ratio of the chlorinated imidazole derivative on the N-substituent to cyclohexanethiol is 1:2-3, and the reflux reaction conditions are 50-70℃ for 3-6 hours.

5. The method for preparing the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd according to claim 4, characterized in that: In step (3), the concentration of the imidazole derivative containing cyclohexyl sulfide on the N-substituent is 1.0-1.5 mol / L in 1,3-dibromopropane, and the heating reflux conditions are 80-120℃ for 6-12h.

6. The method for preparing the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd according to claim 5, characterized in that: In step (4), the organic solvent I is one of tetrahydrofuran, dichloromethane, toluene, 1,4-dioxane, acetonitrile, dimethylformamide, dimethylacetamide and dimethyl sulfoxide, the palladium salt is palladium acetate or palladium chloride, and the alkaline substance is one of sodium acetate, potassium acetate, sodium tert-butoxide, potassium tert-butoxide, sodium tert-pentoxide and potassium tert-pentoxide.

7. The method for preparing the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd according to claim 6, characterized in that: In step (4), the molar ratio of N-bromopropyl-N'-cyclohexyl sulfide-substituted imidazole bromide salt to palladium salt is 1:1, and the reaction time at room temperature is 8-12 h.

8. The method for preparing the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd according to claim 7, characterized in that: In step (5), organic solvent II is one of methanol, tetrahydrofuran, toluene, 1,4-dioxane, acetonitrile, and ethylene glycol dimethyl ether.

9. The method for preparing the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd according to claim 8, characterized in that: In step (5), the mass ratio of the N-bromopropyl-substituted thioether chelate nitrogen heterocyclic carbene palladium complex NHC-Pd to the amino-functionalized magnetic nanoparticles MNPs-NH2 is 3:40, and the stirring reaction conditions are a temperature of 20-100℃ and a time of 18-24h.

10. The application of the magnetically supported thioether chelated nitrogen heterocyclic carbene palladium complex MNPs-NHC-Pd prepared by the method of any one of claims 2-9 as a catalyst in the Suzuki-Miyaura coupling reaction and the reduction reaction of 4-nitrophenol.

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