Single ion type hetero-dinitrogen heterocyclic carbene palladium complex as well as synthesis method and application thereof

Abstract

The invention belongs to the technical field of chemical synthesis and metal organic catalysis, and particularly relates to a single-ion type hetero-dinitrogen heterocyclic carbene palladium complex as well as a synthesis method and application of the single-ion type hetero-dinitrogen heterocyclic carbene palladium complex. The single ion type hetero-dinitrogen heterocyclic carbene palladium complex contains a neutral N-heterocyclic carbene ligand and an ion type N-heterocyclic carbene ligand. The complex can be prepared from a dimer palladium complex of N-heterocyclic carbene and a precursor salt of another N-heterocyclic carbene ligand through a silver metal carbene transfer method. The obtained single ion type hetero-dinitrogen heterocyclic carbene palladium complex can be subjected to an in-situ rearrangement reaction in a solvent, and an exposed palladium metal center generated in the rearrangement process can better catalyze a Suzuki coupling reaction.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical synthesis and metal organic catalysis, and particularly relates to a monoionic heterodiazaheterocyclic carbene palladium complex and a synthesis method and application thereof. Background Art

[0002] The chemical modifiability of nitrogen heterocyclic carbene (NHC) ligands makes them one of the most widely used ligands in metal organic chemistry, and their metal complexes have been successfully applied in various fields such as metal organic catalysis, optoelectronic materials, and drugs. In the field of metal catalysis, researchers can control the catalytic activity of metal centers by changing the electronic steric effect of NHC ligands; they can improve the water solubility of catalysts by introducing functional groups into NHC, thereby realizing catalytic reactions in green solvents, or realizing the loading of metal catalysts, and conveniently recovering catalysts after catalytic reactions to solve a series of problems such as the increasing cost of catalysts and the impact of heavy metal residues on product performance.

[0003] Introducing anionic and cationic substituents into NHC ligands is an effective way to improve the water solubility of nitrogen heterocyclic carbene metal catalysts [Organometallics, 2014, 33, 5470-5482; Organic & Biomolecular Chemistry, 2015, 13, 8556-8560; Applied Organometallic Chemistry, 2018, 32, 4185-4191] and is also one of the methods for loading nitrogen heterocyclic carbene metal catalysts on solid substrates through ion exchange [Applied Organometallic Chemistry, 2015, 29, 678-682], so it has attracted widespread attention. However, metal complexes with single anionic and cationic nitrogen heterocyclic carbene ligands have not been reported. Summary of the invention

[0004] In order to expand the types of ionic nitrogen heterocyclic carbene complexes and study their potential reaction activity and catalytic performance, the present invention discloses a monoionic heterodiaza heterocyclic carbene palladium complex and its synthesis method and application. This type of monoionic heterodiaza heterocyclic carbene palladium complex contains a neutral nitrogen heterocyclic carbene ligand and an ionic nitrogen heterocyclic carbene ligand, and can be prepared from a dimer palladium complex of a nitrogen heterocyclic carbene and a precursor salt of another nitrogen heterocyclic carbene ligand by a silver metal carbene transfer method. The obtained monoionic heterodiaza heterocyclic carbene palladium complex can undergo an in-situ rearrangement reaction in a solvent, and the exposed palladium metal center generated during the rearrangement process can better catalyze the Suzuki coupling reaction.

[0005] The synthesis method of the monoionic heterodiazaheterocyclic carbene palladium complex of the present invention is as follows:

[0006] 2 equivalents of neutral nitrogen heterocyclic carbene precursor salt and 1 equivalent of silver oxide were placed in a solvent and reacted at room temperature for 3 hours. Then, 1 equivalent of quaternary ammonium cationic nitrogen heterocyclic carbene dimer palladium complex was added and the reaction was continued in the solvent for 20 hours to obtain a monocationic heterodiaza heterocyclic carbene palladium complex 3. The synthesis route is as follows:

[0007]

[0008] Among them, the skeleton of nitrogen heterocyclic carbene is imidazole, benzimidazole, R 1 , R 2 , R 3 It is any one of benzyl, methyl, ethyl, isopropyl, phenyl and 3-bromopropyl.

[0009] Alternatively, 2 equivalents of sulfonate anion type nitrogen heterocyclic carbene precursor salt, 1 equivalent of silver oxide and 2 equivalents of KBr are placed in a solvent, reacted at room temperature for 3 hours, and then 1 equivalent of neutral nitrogen heterocyclic carbene dimer palladium complex is added, and the reaction is continued in the solvent for 20 hours to obtain a monoanionic heterodiaza heterocyclic carbene palladium complex 6. The synthesis route is as follows:

[0010]

[0011] Among them, the skeleton of nitrogen heterocyclic carbene is imidazole, benzimidazole, R 1 , R 2 , R 3 It is any one of benzyl, methyl, ethyl, isopropyl, phenyl and 3-bromopropyl.

[0012] After successfully obtaining and fully characterizing the above-mentioned monoionic heterodiazaheterocyclic carbene palladium complexes, it was found that these complexes would undergo an in-situ rearrangement reaction in a mixture of one or more of water, chloroform, and dichloromethane at 25-80°C for 3-36 hours to generate cationic and anionic homodiazaheterocyclic carbene palladium complexes 8 and 9 and neutral homodiazaheterocyclic carbene palladium complexes 10, 11, 12, and 13; the specific reaction formula of the rearrangement reaction is as follows:

[0013]

[0014] Among them, the R substituent is a cationic Net 3 Br, anionic SO 3 K, the skeleton of nitrogen heterocyclic carbene is imidazole, benzimidazole, R 1 , R 2 , R 3 It is any one of benzyl, methyl, ethyl, isopropyl, phenyl and 3-bromopropyl.

[0015] The above-mentioned monoionic heterodiazacyclic carbene palladium complex is used to catalyze the Suzuki coupling reaction of aryl halides and arylboronic acids.

[0016]

[0017] Advantages and technical effects of the present invention: The present invention discloses for the first time a class of monoionic heterodiazacyclic carbene palladium complexes, which can undergo in situ rearrangement reaction in a solvent, and the exposed palladium metal center generated during the rearrangement process can better catalyze the Suzuki coupling reaction. Experiments have shown that compared with neutral (hetero)diazacyclic carbene complexes, dicationic and dianionic dizacyclic carbene complexes, the monoionic heterodiazacyclic carbene palladium complexes developed by the present technology show higher catalytic activity in the Suzuki coupling reaction of different substrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The mixture of complex 6d and neutral isodiazacyclic carbene complex (ratio 1:0.15) captured during the rearrangement of monoionic heterodiazacyclic carbene palladium complex 6d 1 H NMR spectroscopy. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below with reference to the embodiments, wherein the structural formula of the quaternary ammonium cationic nitrogen heterocyclic carbene dimer palladium complex is The structural formula of the neutral nitrogen heterocyclic carbene dimer palladium complex is The structural formula of the neutral nitrogen heterocyclic carbene precursor salt is The structural formula of the sulfonate anion type nitrogen heterocyclic carbene precursor salt is R 1 Taking benzyl as an example, R 2 , R 3 Benzyl, 3-bromopropyl and isopropyl are taken as examples, but this does not limit the present invention and will not be given one by one in the examples.

[0020] Example 1

[0021]

[0022] The neutral 3-bromopropyl modified imidazole precursor salt (36 mg, 0.10 mmol) was dissolved in CH 2 Cl 2 (2 mL), add Ag under light protection 2O (12 mg, 0.05 mmol), stirred at room temperature for 3 hours, slowly added quaternary ammonium cationic nitrogen heterocyclic carbene dimer palladium complex (65 mg, 0.05 mmol) in acetonitrile (5 mL), stirred at room temperature for 20 hours. The resulting suspension was distilled to remove the solvent by vacuum distillation, the product was dissolved with DCM and centrifuged, the filtrate was collected and the solvent was removed by vacuum distillation to obtain a light yellow solid product 3a (83 mg, 0.09 mmol, yield 90%), syn:anti 0.6:1. 1 H NMR (300 MHz, CDCl 3 ): δ7.75(s,2H,Ar-H),7.44-7.28(m,20H,Ar-H),6.98(s,2H,Ar-H),6.75(br-s,4H,Ar-H); syn,5.61(s,2H,NCH 2 Ph), 5.58(s,2H,NCH 2 Ph), 4.81(br-s,2H,NCH 2 ),4.62(br-s,2H,NCH 2 ),3.55(br-s,4H,CH 2 CH 2 N + and BrCH 2 ),3.27(br-s,6H,N + CH 2 CH 3 ),2.76(br-s,2H,CH 2 ),2.64(br-s,2H,CH 2 ),1.20(br-s,9H,CH 3 );anti,5.82(s,2H,NCH 2 Ph), 5.72(s,2H,NCH 2 Ph), 4.71(br-s,2H,NCH 2 ),4.55(br-s,2H,NCH 2 ),3.41(br-s,4H,CH 2 CH 2 N + and BrCH 2 ),3.16(d,6H, 3 J H-H =7Hz,N + CH 2 CH 3 ),2.64(br-s,2H,CH 2 ),2.46(br-s,2H,CH 2),1.02(br-s,9H,CH 3 ). 13 C{ 1 H}NMR (75MHz, CDCl 3 ):δ170.2,169.6(C carbene ),136.8,136.5,129.5,129.4,129.3,129.0,128.9,128.8,128.6,124.1,123.4,122.3,121.5(Ar-C),55.6,55.1(NCH 2 Ph), 54.9, 54.1, 53.8 (CH 2 CH 2 N + and N + CH 2 CH 3 ),49.4,47.9(NCH 2 ),34.0(BrCH 2 ), 33.6, 31.2 (CH 2 ),8.8,8.5(CH 3 ).MS-ESI(m / z):[M–Br] + Calculate for C 32 H 47 Br 3 N 5 Pd + 846, found 846.

[0023] Example 2

[0024]

[0025] Neutral 3-bromopropyl modified benzimidazole precursor salt (42 mg, 0.10 mmol) was dissolved in CH 2 Cl 2 (2 mL), add Ag under light protection 2 O (12 mg, 0.05 mmol), stirred at room temperature for 3 hours, slowly added quaternary ammonium cationic nitrogen heterocyclic carbene dimer palladium complex (65 mg, 0.05 mmol) in acetonitrile (3 mL), stirred at room temperature for 20 hours. The resulting suspension was distilled to remove the solvent by vacuum distillation, the product was dissolved with DCM and centrifuged, the filtrate was collected and the solvent was removed by vacuum distillation to obtain a light yellow solid product 3b (88 mg, 0.09 mmol, yield 89%), syn:anti 0.4:1. 1 H NMR (300 MHz, CDCl 3):δ7.76(s,1H,Ar-H),7.65(s,1H,Ar-H),7.52-7.44(m,7H,Ar-H),7.40-7.30(m,8H),7.24-7.19(m,3H,Ar-H),7.15-7.09(m,3H,Ar-H),7.15-7.09(m,3H,Ar-H),7.02-7.00(d,1H, 3 J H-H =7Hz,Ar-H),6.74(br-s,2H,Ar-H);syn,5.96(s,2H,NCH 2 Ph),5.55(s,2H,NCH 2 Ph),4.99(m,2H,NCH 2 ),4.80(br-s,2H,NCH 2 ),3.65(m,4H,CH 2 CH 2 N + and BrCH 2 ),3.30(m,6H,N + CH 2 CH 3 ),2.65(t,2H, 3 J H-H =6Hz,CH 2 ),2.48(br-s,2H,CH 2 ),1.23(br-s,9H,CH 3 );anti,6.17(m,2H,NCH 2 Ph),5.77(s,2H,NCH 2 Ph),4.89(t,2H, 3 J H-H =7Hz,NCH 2 ),4.70(br-s,2H,NCH 2 ),3.45(m,4H,CH 2 CH 2 N + and BrCH 2 ),3.12(t,6H, 3 J H-H =7Hz,N + CH 2 CH 3 ),2.74(br-s,2H,CH 2 ),2.48(br-s,2H,CH 2 ),1.00(t,9H, 3 J H-H=6Hz,CH 3 ). 13 C{ 1 H}NMR (75MHz, CDCl 3 ):δ182.8,169.2(C carbene ),136.5, 136.3, 136.1, 135.6, 134.6, 129.5, 129.3, 129.2, 128.9, 128.8, 128.4, 128.0, 123.9, 122.3, 112.1, 111.1(Ar-C),55.6,55.2(NCH 2 Ph), 54.1, 53.7, 53.2 (CH 2 CH 2 N + and N + CH 2 CH 3 ),47.8,47.0(NCH 2 ),42.9(BrCH 2 ),31.4,24.6(CH 2 ),8.7,8.5(CH 3 ).MS-ESI(m / z):[M–Br] + Calculate for C 36 H 49 Br3N 5 Pd + 896, found 896.

[0026] Example 3

[0027]

[0028] Neutral diisopropyl-modified imidazole precursor salt (23 mg, 0.10 mmol) was dissolved in CH 2 Cl 2 (2 mL), add Ag under light protection 2 O (12 mg, 0.05 mmol), stirred at room temperature for 3 hours, slowly added quaternary ammonium cationic nitrogen heterocyclic carbene dimer palladium complex (65 mg, 0.05 mmol) in acetonitrile (3 mL), stirred at room temperature for 20 hours. The resulting suspension was distilled to remove the solvent by vacuum distillation, the product was dissolved with DCM and centrifuged, the filtrate was collected and the solvent was removed by vacuum distillation to obtain a light yellow solid product 3c (65 mg, 0.08 mmol, yield 81%). 1 H NMR (300 MHz, CDCl 3 ):δ7.62(d,1H, 3 J H-H<h2 style=";text-align:left;direction:ltr">(2Hz,Ar-H),7.49(dd,2H,<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> J<h2 style=";text-align:left;direction:ltr"> H-H <h2 style=";text-align:left;direction:ltr"> (2Hz,Ar-H), 7.35(m,3H,Ar-H), 6.92(dd,2H,<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> J<h2 style=";text-align:left;direction:ltr"> H-H <h2 style=";text-align:left;direction:ltr"> (2Hz, Ar-H),6.75(d,1H,<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> J<h2 style=";text-align:left;direction:ltr"> H-H <h2 style=";text-align:left;direction:ltr"> (2Hz, Ar-H), 5.73(s, 2H, NCH<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> Ph), 5.47(m,2H,NCHCH<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> ),4.76(t,2H,<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> J<h2 style=";text-align:left;direction:ltr"> H-H <h2 style=";text-align:left;direction:ltr"> <5Hz, NCH<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> ),3.58(m,2H,NCH<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> ),3.44(d,6H,<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> J<h2 style=";text-align:left;direction:ltr"> H-H <h2 style=";text-align:left;direction:ltr"> <7Hz,N<h2 style=";text-align:left;direction:ltr"> + <h2 style=";text-align:left;direction:ltr"> CH<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> CH<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> ),2.72(br-s,2H,CH<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> ),1.58(d,6H,<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> J<h2 style=";text-align:left;direction:ltr"> H-H <h2 style=";text-align:left;direction:ltr"> <7Hz, NCHCH<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> ),1.42(d,6H,<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> J<h2 style=";text-align:left;direction:ltr"> H-H <h2 style=";text-align:left;direction:ltr"> <7Hz, NCHCH<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> ),1.24(t,9H,<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> J<h2 style=";text-align:left;direction:ltr"> H-H <h2 style=";text-align:left;direction:ltr"> <7Hz, CH<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> ).<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> C{<h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> H}NMR(75MHz,CDCl<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> ):δ171.4,165.9(C<h2 style=";text-align:left;direction:ltr"> carbene <h2 style=";text-align:left;direction:ltr"> ),136.6,129.6,129.3,129.0,123.4,122.3,117.7,117.6(Ar-C),56.1(NCH)<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> (Ph), 55.2, 54.1(CH<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> CH<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> N<h2 style=";text-align:left;direction:ltr"> + <h2 style=";text-align:left;direction:ltr"> and N<h2 style=";text-align:left;direction:ltr"> + <h2 style=";text-align:left;direction:ltr"> CH<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> CH<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> ),53.2,53.1(NCHCH<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> ),47.9(NCH<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> ),24.5(CH<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> ),24.1,23.8(NCHCH<h2 style=";text-align:left;direction:ltr"> 3)8.6(NCH 2 CH 3 ).MS-ESI(m / z):[M–Br] + Calculate for C 28 H 48 Br2N 5 Pd + 720, found 720.

[0029] Example 4

[0030]

[0031] Neutral diisopropyl-modified benzimidazole precursor salt (28 mg, 0.10 mmol) was dissolved in CH 2 Cl 2 (2 mL), add Ag under light protection 2 O (12 mg, 0.05 mmol), after stirring at room temperature for 3 hours, a solution of quaternary ammonium cationic nitrogen heterocyclic carbene dimer palladium complex (65 mg, 0.05 mmol) in acetonitrile (3 mL) was slowly added and stirred at room temperature for 20 hours. The resulting suspension was distilled to remove the solvent by vacuum distillation, the product was dissolved with DCM and centrifuged, the filtrate was collected and the solvent was removed by vacuum distillation to obtain a light yellow solid product 3d (77 mg, 0.09 mmol, yield 80%). 1 H NMR (300 MHz, CDCl 3 ): δ7.78(s,1H,Ar-H),7.54(m,4H,Ar-H),7.35(m,4H,Ar-H),7.19(d,2H, 3 J H-H =9Hz,Ar-H),6.85(s,1H,Ar-H),6.07(m,2H,NCHCH 3 ),5.75(s,2H,NCH 2 Ph), 4.85(br-s,2H,NCH 2 ),3.55(br-s,2H,NCH 2 ),3.43(d,6H, 3 J H-H =7Hz,N + CH 2 CH 3 ),2.75(br-s,2H,CH 2 ),1.81(d,6H, 3 J H-H =7Hz,NCHCH 3 ),1.63(d,6H, 3 J H-H=7Hz,NCHCH 3 ),1.25(t,9H, 3 J H-H =7Hz,CH 3 ). 13 C{ 1 H}NMR (75MHz, CDCl 3 ):δ178.4,170.7(C carbene ),136.7,134.2,129.5,129.1,129.0,128.8,123.7,122.8,122.7,122.6,113.3(Ar-C,1×coincident),55.9,(NCH 2 Ph), 55.1(CH 2 CH 2 N + ),54.6(N + CH 2 CH 3 ),54.1(NCHCH 3 )48.2(NCH 2 ),24.6,(CH 2 ),21.8,21.7,21.5(NCHCH 3 ,)7.8(CH 3 ,).MS-ESI(m / z):[M–Br] + Calculate for C 32 H 50 Br2N 5 Pd + 768, found 768.

[0032] Example 5

[0033]

[0034] Sulfonate anion type nitrogen heterocyclic carbene precursor salt (28 mg, 0.10 mmol) and KBr (12 mg, 0.10 mmol) were dissolved in MeOH (1 mL) and 3 drops of H 2 O mixed solvent, add Ag in dark 2O (12 mg, 0.05 mmol) and stirred at room temperature for 3 hours, then slowly added a solution of neutral bromopropyl-modified nitrogen heterocyclic carbene dimer palladium complex (55 mg, 0.05 mmol) in acetonitrile (5 mL), and stirred at room temperature for 20 hours. The resulting suspension was vacuum distilled to remove the solvent, the product was dissolved with DCM and centrifuged, the filtrate was collected and the solvent was removed by vacuum distillation to give a light yellow solid product 6a (80 mg, 0.09 mmol, yield 92%), syn:anti 1:0.7. 1 H NMR (300 MHz, CDCl 3 ): δ7.44(s,4H,Ar-H),7.34(d,4H, 3 J H-H =4Hz,Ar-H),7.23(d,5H, 3 J H-H =5Hz,Ar-H),7.14(d,4H, 3 J H-H =4Hz,Ar-H),7.05(d,2H, 3 J H-H =6Hz,Ar-H),6.86(s,1H,Ar-H),6.76(s,1H,Ar-H),6.56(s,1H,Ar-H),6.48(s,1H,Ar-H); syn,5.52(s,2H,NCH 2 Ph), 5.46(s,2H,NCH 2 Ph), 4.51(br-s,4H,NCH 2 ),3.41(d,2H, 3 J H-H =6Hz,CH 2 Br),3.19(t,2H, 3 J H-H =6Hz,CH 2 S), 2.70(br-s,2H,CH 2 ),2.53-2.51(d,2H, 3 J H-H =6Hz,CH 2 );anti,5.68(s,2H,NCH 2 Ph), 5.60(s,2H,NCH 2 Ph),4.42(d,4H, 3 J H-H =5Hz,NCH 2 ),3.35(br-s,2H,CH 2 Br), 2.95(br-s,2H,CH 2S), 2.68(br-s,2H,CH 2 ),2.51(br-s,2H,CH 2 ). 13 C{ 1 H}NMR (75MHz, CDCl 3 ):δ169.9,168.8(C carbene ),136.9,136.6,129.6,129.4,129.4,129.3,129.2,129.1,123.1,122.9,121.7,121.3(Ar-C),55.1,54.9(NCH 2 Ph), 49.4, 49.2 (NCH 2 ),33.8(BrCH 2 ),33.7(SCH 2 ),32.3,31.4(CH 2 ).MS-ESI(m / z):[MK] - Calculate for C 26 H 32 Br 3 N 4 O 3 PdS - 825,found825.

[0035] Example 6

[0036]

[0037] Sulfonate anion type nitrogen heterocyclic carbene precursor salt (28 mg, 0.10 mmol) and KBr (12 mg, 0.10 mmol) were dissolved in MeOH (1 mL) and 3 drops of H 2 O mixed solvent, add Ag in dark 2 O (12 mg, 0.05 mmol) and stirred at room temperature for 3 hours, then slowly added a solution of a neutral bromopropyl-modified nitrogen heterocyclic carbene dimer palladium complex (60 mg, 0.05 mmol) in acetonitrile (5 mL), and stirred at room temperature for 20 hours. The resulting suspension was vacuum distilled to remove the solvent, the product was dissolved with DCM and centrifuged, the filtrate was collected and the solvent was removed by vacuum distillation to obtain a light yellow solid product 6b (67 mg, 0.07 mmol, yield 73%), syn:anti 1:0.9. 1 H NMR (300 MHz, CDCl 3 ):δ7.53-7.43(dd,9H, 3 J H-H=6Hz,Ar-H),7.23(s,3H,Ar-H),7.169(m,7H,Ar-H),7.09(m,9H,Ar-H),6.98(s,2H,Ar-H),6.53(s,2H,Ar-H);syn,5.91(s,2H,NCH 2 Ph),5.41(s,2H,NCH 2 Ph),4.84(br-s,4H,NCH 2 ),3.48(br-s,2H,CH 2 Br),3.24(t,2H, 3 J H-H =5Hz,CH 2 S),2.92(br-s,2H,CH 2 ),2.59(br-s,2H,CH 2 );anti,6.03(s,2H,NCH 2 Ph),5.63(s,2H,NCH 2 Ph),4.61(s,2H,NCH 2 ),4.45(br-s,2H,NCH 2 ),3.36(br-s,2H,CH 2 Br),2.92(br-s,2H,CH 2 S),2.69(br-s,2H,CH 2 ),2.40(br-s,2H,CH 2 ). 13 C{ 1 H}NMR(75MHz,CDCl 3 ):δ168.2,168.1(C carbene ),137.2,137.0,136.8,136.1,135.9,135.6,134.8,129.8,129.5,129.4,129.3,129.2,129.0,128.6,123.6(Ar-C,1×coincident),54.9,53.3(NCH 2 Ph),49.1,47.0(NCH 2 ),33.3(BrCH 2 ),32.3(SCH 2 ),31.6,27.1(CH 2 ).MS-ESI(m / z):[M-K] - calcdfor C 30 H 34 Br 3 N4 O 3 PdS - 873, found 873.

[0038] Example 7

[0039]

[0040] Sulfonate anion type nitrogen heterocyclic carbene precursor salt (28 mg, 0.10 mmol) and KBr (12 mg, 0.10 mmol) were dissolved in MeOH (1 mL) and 3 drops of H 2 O mixed solvent, add Ag in dark 2 O (12 mg, 0.05 mmol) and stirred at room temperature for 3 hours, then slowly added a solution of a neutral diisopropyl-modified nitrogen heterocyclic carbene dimer palladium complex (42 mg, 0.05 mmol) in acetonitrile (5 mL), stirred at room temperature for 20 hours, and the resulting suspension was vacuum distilled to remove the solvent, the product was dissolved with DCM and centrifuged, the filtrate was collected and the solvent was removed by vacuum distillation to obtain a light yellow solid product 6c (59 mg, 0.08 mmol, yield 80%), 1 H NMR (300 MHz, CDCl 3 ):δ7.50(d,2H, 3 J H-H =7Hz,Ar-H),7.23(s,1H,Ar-H),7.09(d,1H, 3 J H-H =1Hz,Ar-H),6.91(s,1H, 3 J H-H =1Hz,Ar-H),6.79(s,1H, 3 J H-H =1Hz,Ar-H),6.63(s,1H, 3 J H-H =1Hz,Ar-H),5.59(s,2H,NCH 2 Ph), 5.50(m,1H,NCHCH 3 ),5.38(m,1H,NCHCH 3 ),4.55(br-s,2H,NCH 2 ),2.90(t,2H, 3 J H-H =6Hz,SCH 2 ),2.52(t,2H, 3 J H-H =6Hz,CH 2 ),1.46(d,6H, 3 J H-H=7Hz,NCHCH 3 ),1.36(d,6H, 3 J H-H =7Hz,NCHCH 3 ). 13 C{ 1 H}NMR (75MHz, CDCl 3 ):δ170.0,166.5(C carbene ),137.3,129.9,129.5,129.4,129.3,128.5,123.3,121.5,117.8,117.2(Ar-C),54.8(NCH 2 Ph), 53.2(NCH 2 ),52.8,49.9(NCHCH 3 ),49.1(SCH 2 ),27.1(CH 2 ),23.8,23.7(NCHCH 3 ).MS-ESI(m / z):[M–K] - Calculate for C 22 H 32 Br 2 N 4 O 3 PdS - 697, found 697.

[0041] Example 8

[0042]

[0043] Sulfonate anion type nitrogen heterocyclic carbene precursor salt (28 mg, 0.10 mmol) and KBr (12 mg, 0.10 mmol) were dissolved in MeOH (1 mL) and 3 drops of H 2 O mixed solvent, add Ag in dark 2 O (12 mg, 0.05 mmol) and stirred at room temperature for 3 hours, then slowly added a solution of a neutral diisopropyl-modified nitrogen heterocyclic carbene dimer palladium complex (47 mg, 0.05 mmol) in acetonitrile (5 mL), stirred at room temperature for 20 hours, and the resulting suspension was vacuum distilled to remove the solvent, the product was dissolved with DCM and centrifuged, the filtrate was collected and the solvent was removed by vacuum distillation to obtain a light yellow solid product 6d (78 mg, 0.09 mmol, yield 99%), 1 HNMR (300MHz, CDCl 3): δ7.46(m,5H,Ar-H),7.21(m,3H,Ar-H),7.08(m,3H,Ar-H),6.58(s,1H,Ar-H),6.05(m,1H,NCHCH 3 ),5.95(m,1H,NCHCH 3 ),5.60(s,2H,NCH 2 Ph), 4.58(br-s,2H,NCH 2 ),2.97(br-s,2H,CH 2 S), 2.55(br-s, 2H, CH 2 ),1.70(d,6H, 3 J H-H =7Hz,NCHCH 3 ),1.58(d,6H, 3 J H-H =7Hz,NCHCH 3 ). 13 C{ 1 H}NMR (75MHz, CDCl 3 ):δ179.2,169.7(C carbene ),137.3,134.2,134.0,129.3,129.0,128.5,122.7,121.7,113.6,113.0(Ar-C,2×coincident),54.9(NCH 2 Ph), 54.5(NCHCH 3 ),50.4(NCH 2 ),49.1(CH 2 S),27.2(NCHCH 3 ,3×coincident),21.7,21.5(CH 2 ).MS-ESI(m / z):[M–K] - Calculate for C 26 H 35 Br 2 N 4 O 3 PdS - 747, found 747.

[0044] Comparative Example 1

[0045]

[0046] Neutral diisopropyl-modified benzimidazole precursor salt (28 mg, 0.1 mmol) was dissolved in CH 2 Cl 2(2 mL), add Ag under light protection 2 O (12 mg, 0.05 mmol), stirred at room temperature for 3 hours, slowly added a solution of a neutral bromopropyl-modified azoheterocyclic carbene dimer palladium complex (55 mg, 0.05 mmol) in acetonitrile (3 mL), and stirred at room temperature for 20 hours. The resulting suspension was distilled to remove the solvent by vacuum distillation, the product was dissolved with DCM and centrifuged, the filtrate was collected and the solvent was removed by vacuum distillation to obtain a light yellow solid product 7 (74 mg, 0.09 mmol, yield 99%). 1 H NMR (300 MHz, CDCl 3 ): δ7.54(m,4H,Ar-H),7.40(m,3H,Ar-H),7.19(m,2H,Ar-H),6.97(d,1H, 3 J H-H =7Hz,Ar-H),6.75(d,1H, 3 J H-H =2Hz,Ar-H),6.20(m,1H,NCHCH 3 ),6.03(m,1H,NCHCH 3 ),5.80(s,2H,NCH 2 Ph),4.71(t,2H, 3 J H-H =7Hz,NCH 2 ),3.54(t,2H, 3 J H-H =7Hz,CH 2 Br), 2.82(m,2H,CH 2 ),1.81(d,6H, 3 J H-H =7Hz,NCHCH 3 ),1.66(d,6H, 3 J H-H =7Hz,NCHCH 3 ). 13 C{ 1 H}NMR (75MHz, CDCl 3 ):δ179.1,171.6(C carbene ),136.7,134.2,134.1,129.6,129.2,129.0,128.9,122.8,122.63,121.5,113.3(Ar-C,1×coincident),55.3(NCH 2 Ph), 54.5, 54.4 (NCHCH 3 ),49.7(NCH 2 ),33.9(CH2 Br),31.4(NCHCH 3 ,3×coincident),21.8,21.74(CH 2 ).Anal.Calcd.for C 36 H 47 Br 2 N 5 O 3 Pd:C,48.25;H,5.29;N,7.82.MS-ESI(m / z):[M–Br] + Calculate for C 26 H 35 Br 2 N 4 Pd 667, found 667.

[0047] Comparative Example 2

[0048]

[0049] Neutral 3-bromopropyl modified diazaheterocyclic carbene palladium complex (41 mg, 0.05 mmol), acetonitrile (3 mL) and triethylamine (70 μL, 0.50 mmol) were added to a sealed tube and heated at 80°C for 5 hours. Triethylamine (70 μL, 0.50 mmol) was added for the second time and heated at 80°C for 15 hours. After the reaction was completed, the precipitate was collected by filtration and washed with acetone (5 mL × 3) to obtain a light yellow solid product 8 (31 mg, 0.03 mmol, yield 60%).

[0050] Comparative Example 3

[0051]

[0052] PdBr 2 (13 mg, 0.05 mmol) in CH 3 CN (8 mL) was heated at 80 °C for 1 h to obtain [PdBr 2 (CH 3 CN) 2 ] solution. Meanwhile, sulfonate anion type nitrogen heterocyclic carbene precursor salt (28 mg, 0.10 mmol) and KBr (12 mg, 0.10 mmol) were dissolved in MeOH and 3 drops of H 2 O mixed solvent, add Ag in dark 2 O (12 mg, 0.05 mmol) and stirred at room temperature for 3 hours, then [PdBr 2 (CH 3 CN) 2] solution was slowly added dropwise to Ag-NHC and stirred at room temperature for 20 h. The solid and liquid phases were separated and the solid phase was collected. 2 O (5 mL×3) to dissolve the product, and the aqueous phase was collected and dried to obtain an off-white solid product 9 (36 mg, 0.04 mmol, 80%).

[0053] Comparative Example 4

[0054]

[0055] PdBr 2 (67 mg, 0.25 mmol), CH 3 The mixed solution of CN (8 mL) was stirred under reflux at 80 °C for 1 hour to obtain a solution [PdBr 2 (CH 3 CN) 2 ]. Meanwhile, the neutral 3-bromopropyl modified imidazole precursor salt (180 mg, 0.50 mmol) was dissolved in CH 2 Cl 2 (4 mL), add Ag under light protection 2 O (70 mg, 0.30 mmol), stirred at room temperature for 3 hours, and then the above [PdBr 2 (CH 3 CN) 2 ] solution and stirred at room temperature for 20 hours. The resulting suspension was filtered through a funnel, the filtrate was collected, and the filtrate was concentrated to 5 mL by vacuum rotary evaporation, and recrystallized to obtain a light yellow solid product, which is a neutral 3-bromopropyl-modified diazaheterocyclic carbene palladium complex 10 (108 mg, 0.13 mmol, 52%).

[0056] Rearrangement reaction

[0057] The complex 6d obtained in Example 8 was used as a representative complex for rearrangement reaction detection and dissolved in CDCl 3 Store at room temperature for 4 hours. 1 H NMR spectroscopy detected that the ratio of complex 6d to neutral nitrogen heterocyclic carbene palladium complex 13 in the reaction solution was (1:0.15), indicating that the rearrangement conversion rate was 23%. 1 H NMR spectroscopy analysis showed that the complex had been completely converted and the rearrangement reaction was complete ( Figure 1 ). Because the sulfonic acid anion type nitrogen heterocyclic carbene complex is insoluble in CDCl 3 The reaction solution was a light yellow turbid liquid, and the sulfonic acid anion type nitrogen heterocyclic carbene palladium complex 9 (11 mg, 0.13 mmol, 100%) was obtained by filtration. The specific reaction formula of the rearrangement reaction is as follows:

[0058]

[0059] Similarly, the electrically neutral complex 7 obtained in Comparative Example 1 was dissolved in CDCl 3 The product was stored at room temperature and no rearrangement product was found after 60 days.

[0060] Catalytic activity

[0061] In an air atmosphere, aryl halide (0.20 mmol), palladium catalyst (0.002 mmol), phenylboronic acid (0.24 mmol, 29 mg), K 2 CO 3 (0.30mmol, 42mg), H 2 O (600 μL) and internal standard dodecane (0.20 mmol) were added to the reaction flask. After the reaction was completed, dichloromethane (2 mL) and H 2 The organic phase was dried over anhydrous sodium sulfate, 3 drops of the crude product were diluted to 2 mL with dichloromethane, and quantitative analysis was performed by gas chromatography.

[0062] The results showed that for the Suzuki coupling reaction involving five aromatic substrates with different substituents and different halogen substitutions, the monocationic and anionic dinitrogen heterocyclic carbene complexes 3 and 6 showed higher catalytic activity than the neutral dinitrogen heterocyclic carbene complex 7 (Table 1).

[0063] When the substrate is p-chloroacetophenone, the catalytic activities of complexes 3a and 6a are higher than those of dicationic and anionic diazaheterocyclic carbene palladium complexes 8 and 9 and neutral diazaheterocyclic carbene palladium complex 10, and the catalytic yield is >99%, which to some extent reflects the advantages of the monoionic hetero-diazaheterocyclic carbene complex developed by this technology. The catalytic activity is believed to be derived from the fact that such monoionic hetero-diazaheterocyclic carbene complexes can undergo rearrangement reactions in the system, and the uncoordinated metal intermediates produced in the process can better activate the substrate to participate in the reaction.

[0064] Table 1

[0065]

[0066]

[0067] Reaction conditions: aryl halide (0.20 mmol), phenylboronic acid (0.24 mmol), potassium carbonate (0.30 mmol), catalyst (1 mol% [Pd]), H 2 O(600uL), air atmosphere. b The GC yield, with n-dodecane as the internal standard, is the average of two parallel reactions. c TBAB (0.30 mmol) was added.

Claims

1. A monoionic heterodiazacyclic carbene palladium complex, characterized in that: The monoionic heterodiazacyclic carbene palladium complex contains a neutral nitrogen heterocyclic carbene ligand and an ionic nitrogen heterocyclic carbene ligand; the specific structure of the monoionic heterodiazacyclic carbene palladium complex is shown in the following formula: Among them, the R substituent is a cationic NEt3Br or an anionic SO3K, the skeleton of the nitrogen heterocyclic carbene is imidazole or benzimidazole, and R1, R2, and R3 are any one of benzyl, methyl, ethyl, isopropyl, phenyl, and 3-bromopropyl.

2. A method for synthesizing the monoionic heterodiazacyclic carbene palladium complex according to claim 1, characterized in that: The synthesis method is: A neutral nitrogen heterocyclic carbene precursor salt and silver oxide are placed in a solvent, reacted at room temperature for 3 hours, and then a quaternary ammonium cationic nitrogen heterocyclic carbene dimer palladium complex is added, and the reaction is continued in the solvent for 20 hours to obtain a monocationic heterodinitrogen heterocyclic carbene palladium complex; Alternatively, a sulfonate anion nitrogen heterocyclic carbene precursor salt, silver oxide and KBr are placed in a solvent, reacted at room temperature for 3 hours, and then a neutral nitrogen heterocyclic carbene dimer palladium complex is added, and the reaction is continued in the solvent for 20 hours to obtain a monoanionic heterodiaza heterocyclic carbene palladium complex.

3. The synthetic method of the monoionic heterodiazacyclic carbene palladium complex according to claim 2, characterized in that: The structural formulas of the quaternary ammonium cationic nitrogen heterocyclic carbene dimer palladium complex and the neutral nitrogen heterocyclic carbene dimer palladium complex are: The skeleton of the nitrogen heterocyclic carbene is imidazole or benzimidazole, and R1, R2, and R3 are any one of benzyl, methyl, ethyl, isopropyl, phenyl, and 3-bromopropyl.

4. The method for synthesizing a monoionic heterodiazacyclic carbene palladium complex according to claim 2, wherein: The structural formulas of the sulfonate anion type nitrogen heterocyclic carbene precursor salt and the neutral nitrogen heterocyclic carbene precursor salt are: The skeleton of the nitrogen heterocyclic carbene is imidazole or benzimidazole, and R1, R2, and R3 are any one of benzyl, methyl, ethyl, isopropyl, phenyl, and 3-bromopropyl.

5. The method for synthesizing a monoionic heterodiazacyclic carbene palladium complex according to claim 2, wherein: The equivalent ratio of quaternary ammonium cationic nitrogen heterocyclic carbene dimer palladium complex, neutral nitrogen heterocyclic carbene precursor salt and silver oxide is 1:2:1, and the equivalent ratio of neutral nitrogen heterocyclic carbene dimer palladium complex, sulfonate anionic nitrogen heterocyclic carbene precursor salt, silver oxide and KBr is 1:2:1:2; the solvent is one or a mixture of water, methanol, dichloromethane, dimethyl sulfoxide and acetonitrile.

6. An application of the monoionic heterodiazacyclic carbene palladium complex according to claim 1, characterized in that: The monoionic heterodiazaheterocyclic carbene palladium complex is used for catalyzing Suzuki coupling reaction.

7. The use of the monoionic heterodiazacyclic carbene palladium complex according to claim 6, characterized in that: The catalytic Suzuki coupling reaction is: a monoionic heterodiazacyclic carbene palladium complex undergoes a rearrangement reaction in a solvent, and the exposed palladium metal center generated during the rearrangement process catalyzes the Suzuki coupling reaction. The specific reaction formula of the rearrangement reaction is as follows: Among them, the R substituent is a cationic NEt3Br or an anionic SO3K, the skeleton of the nitrogen heterocyclic carbene is imidazole or benzimidazole, and R1, R2, and R3 are any one of benzyl, methyl, ethyl, isopropyl, phenyl, and 3-bromopropyl.

8. The use of the monoionic heterodiazacyclic carbene palladium complex according to claim 7, characterized in that: The rearrangement reaction solvent is one or a mixture of water, chloroform and dichloromethane.

9. The use of the monoionic heterodiazacyclic carbene palladium complex according to claim 7, characterized in that: The rearrangement reaction temperature is 25-80°C, and the rearrangement reaction time is 3-36h.

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