CN104030974A - Aryl-substituted terpyridyl compound and preparation method and application thereof - Google Patents

Abstract

The invention provides an aryl-substituted terpyridine compound, a preparation method and application. Using 2-bromophenyl-2,2':6'2"-terpyridine (II) and aryl borate as raw materials, in a mixed solvent system of toluene:water=4:1 degassed by ultrasonic, Tetrakis(triphenylphosphine) palladium is used as a catalyst, potassium carbonate is used as a base, and it is obtained by reflux reaction for 18-24 hours. This type of compound is suitable for the development and preparation of organic light-emitting materials and fluorescent materials.

Description

A kind of aryl-substituted terpyridine compound and its preparation method and application

technical field

The invention relates to an aryl-substituted terpyridine compound, a preparation method and its application as a photoelectric material in electroluminescence.

technical background

Terpyridine compounds have σ electron donating ability and π electron accepting ability, and can form stable complexes with various metals. In addition, terpyridine compounds have unique magnetic, photophysical and electrochemical properties compared with other compounds. Modification of the terpyridine structure can easily adjust the photophysical and electrochemical properties of the compound, so many novel functional materials can be designed by using these properties, which are used in optoelectronic devices, information storage, molecular switches, molecular machines and solar cells et al. (Synth. Met., 2004, 146, 11-15; J. Am. Chem. Soc., 2004, 126, 4958-4971; Chem. Mat., 2010, 22, 6384-6492).

Terpyridine was first produced by Reported in Sythesis in 1796. Using 2-acetylpyridine and substituted aromatic aldehydes as raw materials, under the action of alkali, one molecule of 2-acetylpyridine undergoes aldol condensation with aromatic aldehydes to generate α, β-unsaturated ketones, and the other molecule of 2-acetyl Under the action of a base, pyridine produces a carbanion-containing intermediate, which undergoes 1,4-addition of unsaturated carbonyl compounds with α,β-unsaturated ketones, and reacts to produce 1,5-diketones. Under the action of amine, 1,5-diketone forms a 1,4-dihydropyridine ring, and then the 1,4-dihydropyridine ring undergoes oxidative dehydrogenation under heating conditions to form an aromatic pyridine ring, Finally, terpyridine compounds (Synthesis, 1976, 1, 1-24) were obtained. After that, Newkome et al. reported hydrazine salt thermal cracking method to synthesize terpyridine compounds in 1972 (J. Org. Chem., 1972, 37, 1329-1336), but the reaction conditions were harsh, the raw materials were complicated, and the route was cumbersome.

The structure of terpyridine compounds can be mainly modified by Stille coupling reaction, Ulmann coupling reaction and Suzuki coupling reaction (Angew.Chem.Int.Ed.2004,43,4704-4734; Angew.Chem.Int.Ed. 2009, 48, 6954-6971).

The Stille coupling reaction is a cross-coupling reaction between an organotin compound and a halogenated hydrocarbon (or trifluoromethanesulfonate) without β-hydrogen under palladium catalysis. It was first discovered by Stille et al. in the 1970s. The reaction is generally carried out under anhydrous and oxygen-free conditions, but the common organotin compounds in experiments usually have high toxicity, thus limiting its application.

The Ulmann coupling reaction is a reaction in which halogenated aromatic compounds and copper powder are co-heated to form biaryl compounds. This reaction was discovered by German chemist Ulmann in 1901, but most of the reactions require higher reaction temperatures. Due to its mild reaction conditions, its application is limited.

The Suzuki coupling reaction is a cross-coupling reaction of aryl boronic acid or boronic acid ester with halogenated aromatic hydrocarbon or olefin under the catalysis of palladium complex. This reaction was first reported by Japanese chemist Akira Suzuki in 1979. In organic synthesis The use of is very extensive (Chem. Rev., 1995, 95, 2457-2483). In addition, the Suzuki coupling reaction has very good tolerance to functional groups, and the reactants can react with functional groups such as -CHO, -COCH ₃ , -CN, -NO ₂ without being affected. Commonly used catalysts in this reaction include Pd(PPh ₃ ) ₄ and Pd(dppf)Cl ₂ , etc. There are also many choices of bases, such as sodium carbonate, cesium carbonate, potassium carbonate, lithium carbonate, etc. The optimum choice of catalyst and base in the reaction is different due to different reaction substrates.

It has been reported in the literature that terpyridine compounds have excellent performance in electroluminescence (ACS Appl. Mat. Interfaces, 2012, 4, 2877-2880). The object of the present invention is to provide a novel aryl-substituted terpyridine compound, its optimal preparation method and its application in photoelectric materials.

Contents of the invention

The purpose of the present invention is to provide an aryl-substituted terpyridine compound, a preparation method and its application as a photoelectric material in electroluminescence.

The technical scheme adopted in the present invention is:

Aryl-substituted terpyridine compounds as shown in formula I

_R in formula I is selected from:

Wherein R ₂ is H, an alkyl group with 1 to 12 carbon atoms, or an aryl group with 7 to 12 carbon atoms.

The present invention also provides a preparation method of the aryl-substituted terpyridine compound as shown in formula I, the method is:

The compound shown in formula II and the compound shown in formula III carry out Suzuki coupling reaction under the protection of nitrogen, with tetrakis (triphenylphosphine) palladium as catalyst, in the mixed solvent of the toluene of ultrasonic degassing: water=4:1, Under alkaline conditions, reflux reaction for 18-24h, after the reaction, the reaction solution is post-treated to obtain the compound shown in formula I; the ratio of the amount of the compound shown in the formula II to the compound shown in the formula III is 1:1.5;

_R in formula III is selected from:

Wherein R ₂ is H, an alkyl group with 1 to 12 carbon atoms, or an aryl group with 7 to 12 carbon atoms.

The amount of the catalyst tetrakis(triphenylphosphine)palladium is usually 5% of the amount of the compound represented by formula II.

The basic condition is to add commonly used bases such as potassium carbonate, sodium carbonate or sodium hydroxide, etc. to keep the pH of the reaction solution alkaline. The post-treatment method of the reaction solution is as follows: after the reaction is finished, add water to the reaction solution to quench the reaction, add dichloromethane to dilute, filter out the insoluble matter, dry the filtrate with anhydrous magnesium sulfate, remove the solvent, and obtain the crude product of the compound shown in formula I, The crude compound represented by formula I was separated and purified by column chromatography using petroleum ether:dichloromethane=5:1 mixed solution as eluent to obtain the pure compound represented by formula I.

The compound shown in the formula II can usually be prepared by the following method: in the methanol solution of 4-bromobenzaldehyde, add 2-acetylpyridine, sodium hydroxide and concentrated ammonia water successively, heat and reflux for 72-80h, and then cool to At room temperature, a gray precipitate was obtained. Filtrate, wash the filter cake with water and methanol successively, and then dry to obtain the compound shown in formula II. The substance of 4-bromobenzaldehyde, 2-acetylpyridine, sodium hydroxide and NH ₃ H ₂ O in concentrated ammonia water The amount ratio is 1:2:1～2:70～100.

The reaction formula is as follows.

This is a preparation method well known to those skilled in the art.

The compound shown in the described formula III can usually be prepared according to the following method: the compound shown in the formula IV and the biboronic acid pinacol ester are treated with [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride As a catalyst, with potassium acetate as base and dimethyl sulfoxide as solvent, heat and reflux for 8 to 10 hours, then add toluene for extraction, take the organic layer, wash it with water and dry it, and remove the solvent under reduced pressure to obtain the crude product shown in formula V. Product, with sherwood oil: the mixed solution of ethyl acetate=4: 1 is eluent, purifies through column chromatography, obtains the pure product of compound shown in formula V, the compound shown in described formula IV, biboronic acid pinacol ester , [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride and potassium acetate are in a ratio of 1:1 to 1.1:0.005 to 0.01:2 to 4.

Described reaction formula is as follows:

_R in formula IV is selected from:

Wherein R ₂ is H, an alkyl group with 1 to 12 carbon atoms, or an aryl group with 7 to 12 carbon atoms.

This is a preparation method well known to those skilled in the art.

The invention provides the aryl-substituted terpyridine compound represented by the formula I, which has passed the test and has luminescent properties, can be used as a luminescent material, and has the advantages of simple reaction conditions, easy-to-obtain raw materials, high yield, and the like.

Description of drawings

Figure 1 Normalized UV-Vis absorption spectra of compounds VI-XI in dichloromethane solution (1×10 ^-5 M)

Figure 2 Normalized fluorescence emission spectra of compounds VI-XI in dichloromethane solution (1×10 ^-7 M)

Figure 3 Normalized fluorescence emission spectra of compounds VI-XI in different solvents (1×10 ^-7 M)

Detailed ways

The present invention will be further described below in conjunction with specific examples, but the protection scope of the present invention is not limited thereto.

The reagents used in the following preparation examples are commercially available reagents:

Embodiment 1: the preparation of 2-bromophenyl-2,2':6'2"-terpyridine (II)

In a round bottom flask containing 200 mL of methanol, 4-bromobenzaldehyde (2.0 g, 10.80 mmol), 2-acetylpyridine (4.4 g, 21.6 mmol), sodium hydroxide (0.44 g, 10.80 mmol) and 60mL of concentrated ammonia water (28%) was heated to 70°C and refluxed for 72h. After cooling to room temperature, a gray precipitate was obtained, which was filtered, and the filter cake was washed with water and methanol, and dried to obtain 2-bromophenyl-2,2':6'2"-terpyridine (3.8g, 89%). ¹ H NMR (CDCl ₃ , 400MHz): δppm 7.36-7.40(m, 3H), 7.48(t, J=8.0Hz, 2H), 7.67(d, J=8.0Hz, 2H), 7.74(d, J= 8.0Hz, 2H), 7.87-7.91(m, 2H), 8.00(d, J=8.0Hz, 2H), 8.68(d, J=8.0Hz, 2H), 8.73-8.76(m, 2H), 8.80( s, 2H).

Embodiment 2: the synthesis of compound shown in formula VI:

Under nitrogen protection, II (388mg, 1mmol), potassium carbonate (552mg, 4.0mmol), tetrakis(triphenylphosphine) palladium (46mg, 0.04mmol), naphthalene borate (1.75g, 7.0mmol) were all added Into the Shrek tube, vacuum and replace with nitrogen three times. Under the atmosphere of N ₂ protection, take 10 mL of ultrasonic degassed toluene: water = 4: 1 mixed solvent, inject it into a Shrek tube, then heat to reflux, and react for more than 20 h. TLC tracking shows that no raw material remains, and the reaction ends. Turn off the heating device, wait for the reaction system to cool down to room temperature, dilute with 20 mL of dichloromethane, wash with saturated brine three times, filter out insoluble matter, and collect the organic phase. After drying with anhydrous magnesium sulfate, the solvent was removed under reduced pressure to obtain a crude product. Using a mixed solvent of petroleum ether: dichloromethane = 1:1 as an eluent, and using 200-300 mesh alumina for column chromatography, 0.36 g of a white solid was isolated, with a yield of 83.5%, and a melting point of 220-221° C. . ¹ H NMR (CDCl ₃ , 400MHz): δppm 7.36-7.40(m, 3H), 7.48(t, J=8.0Hz, 2H), 7.57(d, J=8.0Hz, 2H), 7.67(d, J =8.0Hz, 2H), 7.74(d, J=8.0Hz, 2H), 7.87-7.94(m, 4H), 8.00(d, J=8.0Hz, 2H), 8.68(d, J=8.0Hz, 2H ), 8.73-8.76 (m, 2H), 8.80 (s, 2H). TOF-MS (ES ⁺ ) calcd. for C ₂₇ H ₁₉ N ₃ [M+1] ⁺ : 453.1, found 453.3.

Take 10 mg of the sample and put it into the sample cavity of Quantaurus-Tau C11367-1 fluorescence lifetime system in Hamamatsu, Japan, and the fluorescence lifetime of the product is measured to be 2.64ns.

Embodiment 3: the synthesis of compound shown in formula VII:

Under nitrogen protection, Compound VII was synthesized according to the method in Example 2. The product was a white solid with a yield of 85.0% and a melting point of 229-231°C. ¹ H NMR (CDCl ₃ , 400MHz): δppm 7.01(d, J=2.0Hz, 2H), 7.34-7.38(m, 2H), 7.62(dd, J=2.0Hz, 2H), 7.7(d, J =8.0Hz, 2H), 7.85-7.90(m, 2H), 7.95-8.03(m, 4H), 8.69(d, J=8.0Hz, 2H), 8.73-8.77(m, 3H), 8.80(s, 2H).TOF-MS(ES ⁺ )calcd.for C ₂₈ H ₂₁ N ₃ O[M+1] ⁺ : 462.2, found 462.1.

The fluorescence lifetime of this product is 2.15ns, and the test method is the same as that in Example 2.

Embodiment 4: the preparation of compound shown in formula III

Wherein, R ₁ is a substituted carbazolyl, the structure is as follows:

Wherein, R ₂ is an alkyl chain with 6 carbon atoms.

N-bromosuccinimide bromination: at room temperature, dissolve carbazole (15.0g, 89.88mmol) in 150mL N,N-dimethylformamide, then add N-bromosuccinyl Imine (15.9 g, 90 mmol) and the reaction was stirred overnight. The reaction solution was extracted three times with ethyl acetate, the combined organic layers were washed three times with saturated brine, and then the organic phase was dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. The obtained crude product was recrystallized from ethanol to obtain 11.5 g of a pale yellow solid. The yield was 66.8%.

Alkyl chain substitution: Add brominated carbazole (4.10g, 16.66mmol) into dimethyl sulfoxide (80mL) at room temperature, stir until all solids are dissolved, then add hexyl bromide (2.49mL , 17.49mmol), potassium hydroxide (7.46g, 133.28mmol) and potassium iodide (0.28g, 1.67mmol), mixed and stirred for more than 24h. Then it was fully washed with saturated brine, extracted with dichloromethane, and the organic phase was separated and dried over anhydrous magnesium sulfate to obtain a crude product. With petroleum ether as eluent, 5.0 g of light yellow oily liquid was obtained by column chromatography with a yield of 90.9%. ¹ H NMR (CDCl ₃ , 400MHz): δppm0.85(s, 3H), 1.24(s, 12H), 1.25-1.52(m, 8H), 4.15(m, 2H), 7.57(m, 2H), 7.67 -7.73(m, 5H).

Embodiment 5: the synthesis of compound shown in formula VIII:

The obtained brominated carbon six-chain substituted carbazole (1.5g, 4.53mmol), [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride (116mg, 0.038mmol), potassium acetate (1.35g, 13.8mmol) and dipivaloyl diboron (1.2g, 4.83mmol) were placed in a 100mL round-bottomed flask, 20mL of dimethyl sulfoxide was added, and after reacting at 95°C for 8h, 100mL of toluene was added for extraction, and The organic layer was washed with water to remove dimethyl sulfoxide, dried, and the solvent was removed to obtain a crude product. The crude product was purified by column chromatography using petroleum ether:dichloromethane=4:1 as the eluent to obtain a pure product with a yield of 75%. ¹ H NMR (CDCl ₃ , 400MHz): δppm 0.85(s, 4H), 1.25-1.52(m, 7H), 1.92-1.95(m, 2H), 4.35(s, 2H), 7.33(s, 1H) , 7.45-7.57(m, 3H), 8.34(d, J=8.0Hz, 1H), 8.45(s, 1H, J=8.0Hz), 9.10(s, 1H).

The fluorescence lifetime of this product is 2.08ns, and the test method is the same as that in Example 2.

Embodiment 6: the synthesis of compound shown in formula IX:

Alkyl chain substitution: the synthesis method is the same as the alkyl chain substitution in Example 4. After post-treatment, a light yellow oily liquid was obtained with a yield of 86.9%.

Bromination of N-bromosuccinimide: the synthesis method is the same as the bromination in Example 4. A yellow oily liquid was obtained after post-treatment with a yield of 84.2%.

The synthetic method of bromocarbon chain fluorene boronic acid is the same as embodiment 4. The obtained crude product was separated and purified by column chromatography, and the eluent was petroleum ether to obtain 6.8 g of a colorless oily liquid with a yield of 50.4%. ¹ H NMR (CDCl ₃ , 400MHz): δppm 0.57(s, 4H), 0.72-0.76(m, 6H), 0.88-1.26(m, 12H), 1.38(s, 12H), 1.98(d, 4H), 7.29(m, 3H), 7.70(m, 1H), 7.79(s, 1H), 7.81(d, 1H).

Under nitrogen protection, Compound IX was synthesized according to the method in Example 2. The product was a white solid with a yield of 80% and a melting point of 110-111°C. ¹ H NMR (CDCl ₃ , 400MHz): δppm 0.76-0.80 (m, 6H, CH ₃ ), 1.07-1.44 (m, 16H, CH ₂ ), 1.95-2.05 (m, 4H, CH ₂ ), 7.34-7.38 (m, 5H), 7.64-7.71(m, 2H), 7.72-7.81(m, 4H), 7.85-7.95(m, 2H), 8.04-8.06(m, 2H), 8.69-8.74(m, 2H) , 8.75-8.80 (dd, 2H), 8.83 (s, 2H). TOF-MS (ES ⁺ ) calcd. for C ₄₆ H ₄₇ N ₃ [M+1] ⁺ : 642.4, found 642.1.

The fluorescence lifetime of this product is 2.45ns, and the test method is the same as that in Example 2.

Embodiment 7: the synthesis of compound shown in formula X:

Under nitrogen protection, Compound X was synthesized according to the method in Example 2. The product was a white solid with a yield of 82% and a melting point of 217-218°C. ¹ H NMR (CDCl ₃ , 400MHz): δppm 7.04-7.08 (m, 2H), 7.15-7.19 (m, 6H), 7.27-7.31 (m, 4H), 7.35-7.38 (m, 2H), 7.56 ( d, J=8.0Hz, 2H), 7.71(d, J=8.0Hz, 2H), 7.87-7.91(m, 2H), 7.98(d, J=8.0Hz, 2H), 8.68(d, J=8.0 Hz, 2H), 8.74-8.76(m, 2H), 8.80(s, 2H). TOF-MS(ES ⁺ ) calcd. for C ₃₉ H ₂₈ N ₄ [M+1] ⁺ : 553.3, found 553.8.

The fluorescence lifetime of this product is 3.15ns, and the test method is the same as that in Example 2.

Embodiment 8: the synthesis of compound shown in formula XI:

Under nitrogen protection, Compound XI was synthesized according to the method in Example 2. The product was a white solid with a yield of 84% and a melting point of 198-199°C. ¹ H NMR (CDCl ₃ , 400MHz): δppm 7.12-7.14(m, 5H), 7.16-7.19(m, 6H), 7.27-7.31(m, 4H), 7.35-7.38(m, 2H), 8.68(d , J=8.0Hz, 2H), 8.74-8.76 (m, 2H), 8.80 (s, 2H). TOF-MS (ES ⁺ ) calcd. for C ₃₉ H ₂₈ N ₄ [M+1] ⁺ : 478.5, found 478.8.

The fluorescence lifetime of this product is 2.45ns, and the test method is the same as that in Example 2.

Although the invention has been described in detail with preferred embodiments, it is not intended to limit the invention. Any person skilled in the art should be able to make various modifications and changes without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be regarded as the scope defined by the appended claims.

Claims (3)

1. A terpyridine compound containing aryl substitution, its general structural formula is: wherein _R is selected from: Wherein R ₂ is H, an alkyl group with 1 to 12 carbon atoms, and an aryl group with 7 to 12 carbon atoms. 2. a synthetic method containing aryl-substituted terpyridine compounds as claimed in claim 1, characterized in that: 2-bromophenyl-2, 2': 6'2 "-terpyridine (II) and The aryl borate was reacted under reflux for 18-24 hours in a mixed solvent system of toluene:water=4:1 degassed by ultrasonic, tetrakis(triphenylphosphine)palladium was used as catalyst, and potassium carbonate was used as base for 18-24h to obtain the target compound. 3. The application of an aryl-substituted terpyridine compound as a light-emitting material, which can be used as a fluorescent material and as a light-emitting layer in an organic light-emitting diode.