Aggregation-induced emission ruthenium complex as well as preparation method and application thereof

Abstract

The invention discloses an aggregation-induced emission ruthenium complex as well as a preparation method and application thereof, and belongs to the field of phosphorescent materials. Three ruthenium complexes are prepared by taking 2, 2 '-dipyridyl and derivatives thereof as ligands, and the research on the photophysical properties of the ruthenium complexes shows that the ruthenium complexes prepared by the invention have excellent aggregation-induced emission properties and have important application value in the field of phosphorescent materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the preparation and application of three transition metal ruthenium complexes with aggregation-induced emission properties, which belongs to the field of phosphorescent materials. BACKGROUND

[0002] Traditional fluorescent molecules usually have strong fluorescence in dilute solution, and the fluorescence will weaken or even quench at high concentration. In 2001, Tang Benzhong et al. found that a class of small organic molecules had almost no fluorescence in dilute solution, but showed bright fluorescence emission in the aggregated state (Chem. Commun., 2001, 1740-1741). They named this new phenomenon as aggregation-induced emission (AIE). The discovery of the aggregation-induced emission phenomenon provides an effective way to solve the major scientific problem of aggregation-induced emission quenching, and greatly promotes the application and development of high-efficiency solid-state light-emitting materials. So far, most of the AIE molecules reported in the literature are pure organic small molecules, and there are relatively few new aggregation-induced phosphorescent emission (AIPE) materials based on transition metal complexes. As a kind of phosphorescent material, transition metal ruthenium complexes have been widely used in photocatalysis (Angew. Chem. Int. Ed, 2022, 61, e202203390), photodynamic therapy (JACS Au, 2024, 4, 1081-1096), biological imaging (Chem. Commun., 2024, 60, 6308-6311) and sensors (New J. Chem., 2022, 46, 169-177) and other fields. Therefore, it is of great application value to create ruthenium complexes with excellent aggregation-induced emission properties. SUMMARY

[0003] The purpose of the present application is to provide a preparation method of ruthenium complexes Ru1-Ru3 with aggregation-induced emission properties and their aggregation-induced emission properties.

[0004] The technical solution adopted by the present application is: the preparation method of ruthenium complexes Ru1-Ru3 is to synthesize 2,2'-bipyridine derivative ligand by using 5-bromo-2,2'-bipyridine and aryl boronic acid derivative or diphenylamine as reactants, then coordinating 2,2'-bipyridine derivative ligand and 2,2'-bipyridine with ruthenium metal ion at the same time, and finally synthesizing by replacing anion, and the structure is as follows:

[0005]

[0006] The synthesis steps of the ruthenium complex are as follows:

[0007] (1) Synthesis of ligand 5-phenyl-2,2'-bipyridine and 5-(4-diphenylaminophenyl)-2,2'-bipyridine: Suzuki cross-coupling reaction was carried out under N2 protection with 5-bromo-2,2'-bipyridine and arylboronic acid derivatives as reactants, potassium carbonate as base, tetrakis(triphenylphosphine)palladium as catalyst, and ethanol / water mixed solution as solvent. The reaction progress was tracked by thin layer chromatography. After the reaction was completed, the target product was separated by column chromatography;

[0008] (2) Synthesis of ligand 5-(diphenylamino)-2,2'-bipyridine: Buchwald-Hartwig cross-coupling reaction was carried out under N2 protection with 5-bromo-2,2'-bipyridine and diphenylamine as reactants, sodium tert-butoxide as base, tris(dibenzylideneacetone)dipalladium as catalyst, 1,1'-binaphthalene-2,2'-diphenylphosphine as external ligand, and anhydrous toluene as solvent. The reaction progress was tracked by thin layer chromatography. After the reaction was completed, the target product was separated by column chromatography;

[0009] (3) Synthesis of ruthenium complexes: A round-bottom flask was charged with RuCl3·3H2O, 6.0 equivalents of LiCl, and 2.0 equivalents of 2,2'-bipyridine derivative ligand. The reaction was carried out under N2 protection in N,N-dimethylformamide at 100-150°C with magnetic stirring for 6h. After the reaction was completed, the reaction solution was cooled to room temperature, 5.0 times the volume of N,N-dimethylformamide was added and stirred uniformly, and then allowed to stand. The intermediate was obtained by suction filtration. The intermediate and 1.1 equivalents of 2,2'-bipyridine were reacted in a 7:3 volume ratio of ethanol / water mixed solution under N2 protection. After the reaction was completed, the complex was purified by silica gel column chromatography under reduced pressure. The obtained complex was dissolved in water, 20 equivalents of saturated aqueous ammonium hexafluorophosphate solution was added, and stirred at room temperature for 2h. The solid was collected by suction filtration and washed with water. After drying, the target product was obtained.

[0010] Further, the preparation method of the 2,2'-bipyridine derivative ligand and the ruthenium complexes Ru1-Ru3 is as follows:

[0011] (1) Synthesis of ligand 5-phenyl-2,2'-bipyridine and 5-(4-diphenylaminophenyl)-2,2'-bipyridine: A round bottom flask was charged with 5-bromo-2,2'-bipyridine 2.0 mmol, aryl boronic acid derivative (1.5 equiv.), potassium carbonate (2.0 equiv.) and tetrakis(triphenylphosphine)palladium (3.0% equiv.). Vacuum was applied and N2was introduced. A 3:1 volume ratio of ethanol / water mixture (16 mL) was added under N2protection. The reaction was stirred magnetically at 80 °C for 12 h. After the reaction was completed, the mixture was extracted with dichloromethane, and the organic phases were combined and concentrated under reduced pressure. The target product was isolated by column chromatography;

[0012] (2) Synthesis of ligand 5-(diphenylamino)-2,2'-bipyridine: 5-Bromo-2,2'-bipyridine 2.0 mmol and diphenylamine (1.2 equiv.) were dissolved in 20 mL of pre-deaerated anhydrous toluene under N2protection. Then sodium tert-butoxide (0.9 equiv.), tris(dibenzylideneacetone)dipalladium (1.0% equiv.) and 1,1'-binaphthalene-2,2'-diphenylphosphine (2.5% equiv.) were added. The reaction was stirred magnetically at 130 °C for 24 h. After the reaction was completed, the mixture was extracted with dichloromethane, and the organic phases were combined and concentrated under reduced pressure. The target product was isolated by column chromatography;

[0013] (3) Synthesis of ruthenium complex: A round bottom flask was charged with RuCl3-3H2O (0.6 mmol), LiCl (6.0 equiv.) and 2,2'-bipyridine derivative ligand (2.0 equiv.). Vacuum was applied and N2was introduced. A pre-deaerated N,N-dimethylformamide was added under N2protection. The reaction was stirred magnetically at 100-150 °C for 6 h. After the reaction was completed, the reaction solution was cooled to room temperature, 20 mL of acetone was added and stirred uniformly, and the mixture was left to stand at low temperature for 24 h. The di-coordinated intermediate was obtained by suction filtration. The di-coordinated intermediate and 2,2'-bipyridine (1.1 equiv.) were added to a round bottom flask, vacuum was applied and N2was introduced. A 7:3 volume ratio of ethanol / water mixture (25 mL) was added under N2protection. The reaction was stirred magnetically at 90 °C for 8 h. After the reaction was completed, the mixture was concentrated under reduced pressure, and the complex was purified by silica gel column chromatography. The obtained complex was dissolved in water, and a saturated aqueous solution of ammonium hexafluorophosphate (20.0 equiv.) was added. The mixture was stirred at room temperature for 2 h, and the solid was collected by suction filtration and washed with water. The target product was obtained after drying. The structure of the product was confirmed by 1 H NMR, 13 C NMR and high resolution mass spectrometry.

[0014] The above ruthenium complexes include the following derivatives:

[0015] Compound Ru1: 2,2'-bipyridine derivative ligand is selected from 5-phenyl-2,2'-bipyridine;

[0016] Compound Ru2: 2,2'-bipyridine derivative ligand is selected from 5-(diphenylamino)-2,2'-bipyridine;

[0017] Compound Ru3: 2,2'-bipyridine derivative ligand is selected from 5-(4-diphenylaminophenyl)-2,2'-bipyridine.

[0018] Advantages of the present application: 2,2'-bipyridine derivative ligand is synthesized by Suzuki cross-coupling and Buchwald-Hartwig cross-coupling reaction, and the synthesis method is environmentally friendly and simple and efficient.

[0019] Ruthenium complexes modified by different substituents can be obtained by modular design, and the ruthenium complexes have excellent aggregation-induced emission properties. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the emission spectrum of compound Ru1 under different water contents (solvent is tetrahydrofuran / water, 1 × 10 -5 mol / L).

[0021] Figure 2 is the emission spectrum of compound Ru2 under different water contents (solvent is tetrahydrofuran / water, 1 × 10 -5 mol / L).

[0022] Figure 3 is the emission spectrum of compound Ru3 under different water contents (solvent is tetrahydrofuran / water, 1 × 10 -5 mol / L). DETAILED DESCRIPTION

[0023] Example 1 Synthesis of compound Ru1

[0024] (1) Synthesis of 2,2'-bipyridine derivative ligand:

[0025] A round-bottom flask was added with 5-bromo-2,2'-bipyridine 2.0 mmol, phenylboronic acid (1.5 equiv.), potassium carbonate (2.0 equiv.) and tetrakis(triphenylphosphine)palladium (3.0% equiv.) in sequence. Vacuumize and protect with N2, and then add a pre-oxygen-free volume ratio of 3:1 ethanol / water mixed solution 16 mL under N2 protection. Perform Suzuki cross-coupling reaction at 80°C under magnetic stirring for 12 h. After the reaction is completed, extract with dichloromethane, combine the organic phases, reduce pressure and concentrate, and separate the 2,2'-bipyridine derivative ligand by silica gel column chromatography, with a yield of 78%;

[0026] (2) Synthesis of Ruthenium Complexes:

[0027] Into a round bottom flask was added RuCl3-3H2O (0.6 mmol), LiCl (6.0 equiv.) and 2,2'-bipyridine derivative (2.0 equiv.). Vacuumed and protected by N2, pre-oxygen-removed N,N-dimethylformamide 4 mL was added under N2 protection. The reaction was stirred magnetically at 100-150 °C for 6 h. After the reaction was completed, the reaction solution was cooled to room temperature, and then acetone 20 mL was added and stirred uniformly, and then low-temperature standing was performed for 24 h, and then filtration was performed to obtain an intermediate. The intermediate and 2,2'-bipyridine (1.1 equiv.) were added into a round bottom flask, vacuumed and protected by N2, and a mixed solution of ethanol / water (7:3 by volume) 25 mL was added under N2 protection. The reaction was stirred magnetically at 90 °C for 8 h. After the reaction was completed, concentration was performed under reduced pressure, and then the complex was purified by silica gel column chromatography. The obtained complex was dissolved in water, and then a saturated aqueous solution of ammonium hexafluorophosphate (20.0 equiv.) was added, and then stirring was performed at room temperature for 2 h, and then the solid was collected by filtration and washed with water, and then the target product was obtained after drying, with a yield of 40%, and the structural characterization data were as follows: 1 H NMR (500 MHz, DMSO-d6) δ 8.92(dd, J = 12.7, 8.3 Hz, 4H), 8.82 (d, J = 8.2 Hz, 2H), 8.51 (dd, J = 8.5, 2.1Hz, 2H), 8.20 (q, J = 8.1 Hz, 4H), 7.90 (dd, J = 10.8, 5.9 Hz, 4H), 7.76 (d,J = 2.0 Hz, 2H), 7.57 (dt, J = 22.0, 6.4 Hz, 4H), 7.51 - 7.43 (m, 10H). 13 CNMR (101 MHz, DMSO-d6): δ 156.78, 156.52, 156.23, 155.40, 151.74, 151.63,148.12, 138.72, 137.90, 137.86, 135.63, 134.39, 129.63, 129.39, 127.85,127.74, 126.92, 124.61, 124.48. HRMS (ESI, m / z) C 42 H 32 N6Ru [M - 2PF6] 2+ 361.0861, found: 361.0865, calcd: PF6 ⁻: 144.9647, found: 144.9649.

[0028] Example 2 Synthesis of compound Ru2

[0029] (1) Synthesis of 2,2'-bipyridine derivative ligand:

[0030] Under N2protection, 5-bromo-2,2'-bipyridine 2.0 mmol and diphenylamine (1.2 equiv.) were dissolved in 20 mL of pre-oxygen-free anhydrous toluene. Then sodium tert-butoxide (0.9 equiv.), tris(dibenzylideneacetone)dipalladium (1.0% equiv.) and 1,1'-binaphthalene-2,2'-diphenylphosphine (2.5% equiv.) were added. The Buchwald-Hartwig cross-coupling reaction was magnetically stirred at 130 °C for 24 h. After the reaction was completed, it was extracted with dichloromethane, the organic phases were combined, concentrated under reduced pressure, and the 2,2'-bipyridine derivative ligand was separated by column chromatography with a yield of 85%;

[0031] (2) Synthesis of ruthenium complex:

[0032] The ruthenium complex of Example 2 was prepared in the same way as Example 1, except that the 2,2'-bipyridine derivative ligand used in the synthesis of the ruthenium complex in Example 2 was 5-(diphenylamino)-2,2'-bipyridine.

[0033] Ru2 yield 35%, structural characterization data as follows: 1 H NMR (400 MHz, DMSO-d6) δ 8.79 (d, J =8.2 Hz, 2H), 8.54 (d, J = 9.2 Hz, 2H), 8.32 (d, J = 8.2 Hz, 2H), 8.15 (td, J= 7.8, 1.5 Hz, 2H), 8.02 (d, J = 5.4 Hz, 2H), 7.79 (td, J = 7.8, 1.5 Hz, 2H),7.57 (t, J = 6.6 Hz, 2H), 7.51 - 7.41 (m, 3H), 7.42 - 7.31 (m, 9H), 7.23 (t,J = 7.4 Hz, 4H), 7.09 (d, J = 7.6 Hz, 9H), 6.94 - 6.87 (m, 3H). 13C NMR (151 MHz, DMSO-d6) δ 156.35, 156.13, 151.49, 149.89, 146.41, 143.85, 139.81, 137.64, 137.20, 130.15, 127.69, 126.15, 125.71, 125.50, 124.59, 124.42, 124.19, 122.53. HRMS (ESI, m / z) Calcd for C 54 H 42 N8Ru [M - 2PF6] 2+ 452.1283, found: 452.1291.

[0034] Example 3 Synthesis of compound Ru3

[0035] Example 3 was prepared in the same way as Example 1, except that in the synthesis of the 2,2'-bipyridine derivative ligand in Example 3, the aryl boronic acid derivative used was 4-boronic acid triphenylamine.

[0036] Ru3 yield 37%, structural characterization data as follows: 1 H NMR (400 MHz, DMSO-d6) δ 8.89 - 8.76 (m, 6H), 8.44 (dt, J = 8.6, 2.6 Hz, 2H), 8.22 - 8.13 (m, 4H), 7.93 - 7.79 (m, 4H), 7.75 (dd, J = 4.5, 2.1 Hz, 2H), 7.59 - 7.49 (m, 4H), 7.41 - 7.33 (m, 12H), 7.14 (t, J = 7.5 Hz, 4H), 7.05 (d, J = 8.0 Hz, 8H), 6.97 - 6.87 (m, 4H). 13C NMR (151 MHz, DMSO-d6) δ 157.21, 157.02, 157.00, 156.81, 154.86, 154.77, 152.21, 152.01, 151.96, 151.90, 149.31, 147.62, 147.52, 146.82, 138.49, 138.42, 138.37, 138.29, 138.25, 134.78, 130.30, 128.30, 128.22, 127.95, 127.01, 126.48, 125.56, 125.06, 124.75, 122.07. HRMS (ESI, m / z) Calcd for C 66 H 50 N8Ru [M - 2PF6] 2+ 528.1596, found: 528.1615.

[0037] Example 4 Test of AIE property of compound Ru1

[0038] Ru1 was dissolved in tetrahydrofuran to prepare a solution with a concentration of 2 × 10 -4 mol / L, and the above solution, tetrahydrofuran and water were mixed in different volume ratios to prepare mixed solutions with different water contents (concentration of 1 × 10 -5 mol / L), and the emission spectrum was tested after 24 h. Figure 1 The results show that in the tetrahydrofuran / water mixed solution, the luminescence of the compound gradually increases with the increase of the content of the poor solvent water, and when the water content increases to 70%, the emission intensity reaches the maximum and the maximum emission wavelength has a slight blue shift, and I / I0 is 2.25 (I represents the emission intensity of Ir1 in the tetrahydrofuran / water system, and I0 represents the emission intensity of Ir1 in pure tetrahydrofuran). The results show that the compound Ru1 has excellent aggregation-induced emission properties.

[0039] Example 5 Test of AIE property of compound Ru2

[0040] Ru2 was dissolved in tetrahydrofuran to prepare a solution with a concentration of 2 × 10 -4 mol / L, and the above solution, tetrahydrofuran and water were mixed in different volume ratios to prepare mixed solutions with different water contents (concentration of 1 × 10 -5 mol / L), and the emission spectrum was tested after 24 h. Figure 2The results show that in the tetrahydrofuran / water mixed solution, the luminescence of the compound gradually increases with the increase of the content of the poor solvent water, the emission intensity reaches the maximum when the water content increases to 70%, and the maximum emission wavelength slightly blue shifts, and I / I0 is 2.28. The results show that the compound Ru2 has excellent aggregation-induced emission properties.

[0041] Example 6 Test of AIE properties of compound Ru3

[0042] Ru3 was dissolved in tetrahydrofuran to prepare a solution with a concentration of 2 × 10 -4 mol / L, and then the above solution, tetrahydrofuran and water were mixed in different volume ratios to prepare mixed solutions with different water contents (concentration of 1 × 10 -5 mol / L), and the emission spectrum was tested after 24 h. Figure 3 The results show that in the tetrahydrofuran / water mixed solution, the luminescence of the compound gradually increases with the increase of the content of the poor solvent water, the emission intensity reaches the maximum when the water content increases to 90%, and the maximum emission wavelength slightly blue shifts, and I / I0 is 4.01. The results show that the compound Ru3 has excellent aggregation-induced emission properties.

[0043] The above examples are only used to illustrate the present application, and any equivalent transformation and improvement on the basis of the technical scheme of the present application should not be excluded from the protection scope of the present application.

Claims

1. An aggregation-induced emission ruthenium complex characterized in that: The ruthenium complex is formed by coordination of 2,2'-bipyridine and its derivatives with a ruthenium metal ion, and the structure is as follows: ； The 2,2'-bipyridine and its derivatives are selected from 2,2'-bipyridine, 5-phenyl-2,2'-bipyridine, 5-(diphenylamino)-2,2'-bipyridine or 5-(4-diphenylaminophenyl)-2,2'-bipyridine.

2. The method of claim 1, wherein the method is characterized by: The synthesis steps of the ruthenium complex are as follows: (1) Synthesis of ligands 5-phenyl-2,2'-bipyridine and 5-(4-diphenylaminophenyl)-2,2'-bipyridine: Suzuki cross-coupling reaction occurs under N2 protection, using 5-bromo-2,2'-bipyridine and aryl boronic acid derivatives as reactants, potassium carbonate as base, tetrakis(triphenylphosphine)palladium as catalyst, and ethanol / water mixed solution as solvent, the reaction progress is tracked by thin layer chromatography, and after the reaction is completed, the target product is separated by column chromatography; (2) Synthesis of ligand 5-(diphenylamino)-2,2'-bipyridine: Buchwald-Hartwig cross-coupling reaction occurs under N2 protection, using 5-bromo-2,2'-bipyridine and diphenylamine as reactants, sodium tert-butoxide as base, tris(dibenzylideneacetone)dipalladium as catalyst, 1,1'-binaphthalene-2,2'-biphenylphosphine as external ligand, and anhydrous toluene as solvent, the reaction progress is tracked by thin layer chromatography, and after the reaction is completed, the target product is separated by column chromatography; (3) Synthesis of ruthenium complex: add RuCl3·3H2O, 6.0 equivalents of LiCl and 2.0 equivalents of 2,2'-bipyridine derivative ligand into a round-bottom flask, magnetically stir the reaction under N2 protection at 100-150°C in N,N-dimethylformamide, after the reaction is completed, cool the reaction liquid to room temperature, add 5.0 times the volume of acetone to N,N-dimethylformamide and stir uniformly, stand, and then filter to obtain an intermediate; react the intermediate and 1.1 equivalents of 2,2'-bipyridine in a volume ratio of 7:3 of ethanol / water mixed solution under N2 protection, after the reaction is completed, reduce the pressure to concentrate, purify the complex by silica gel column chromatography; dissolve the obtained complex in water, add 20 equivalents of saturated aqueous ammonium hexafluorophosphate solution, stir at room temperature, collect the solid by filtration and wash with water, and dry to obtain the target product.

3. Use of an aggregation-induced emission ruthenium complex according to claim 1, characterized in that: The ruthenium complex is applied to the field of phosphorescent materials.

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