Preparation method and application of asymmetric polyarylether cluster luminescent material

Abstract

The invention discloses a method for preparing an asymmetric polyaryl ether cluster luminescent material, wherein the cluster luminescent material has a structure as shown in the following formula 1 or formula 2: wherein R is H, an electron-donating group or an electron-withdrawing group; the electron-donating group is dimethylamino, methoxy or diphenylamino; the electron-withdrawing group is halogen, cyano, trifluoromethyl or nitro; triphenylchloromethane is attacked by DBU to form a trityl carbonium ion, which is then reacted with a polyaryl secondary alcohol or primary alcohol substrate to obtain the cluster luminescent material. The preparation method does not require strict reaction environment control, does not require a metal catalyst, and has the advantages of being green and economical, simple reaction, high selectivity and high yield.

Description

Technical Field

[0001] The invention relates to the field of synthesis of organic fluorescent molecules, and in particular to a method for preparing an asymmetric polyarylether cluster luminescent material and application of the material in a luminescent device. Background Art

[0002] As a new type of organic light-emitting material, non-conjugated cluster luminescent materials have important value in both basic theory and applied research, and are the focus and difficulty of current research in the field. How to design new non-conjugated cluster luminescent materials is of great significance to exploring its theory and expanding its application. However, at present, there are great limitations in the methods of synthesizing various non-conjugated cluster luminescent molecules. Non-conjugated polyaryl ether cluster luminescent materials are one of the important research objects. Therefore, finding a simple and effective preparation method of non-conjugated polyaryl ethers has always been the focus of attention in the field of organic synthesis and optical materials.

[0003] It is difficult to obtain asymmetric polyaryl ether non-conjugated cluster luminescent materials through existing organic synthesis routes. For example, how to combine tertiary carbon such as triphenylmethane and secondary carbon such as diphenylmethane through an oxygen atom is worth studying in terms of organic synthesis methodology. According to investigations, some existing organic synthesis routes have very harsh conditions. For example, it was previously reported that pentaphenyl dimethyl ether was generated by catalysis with zinc chloride (Tetrahedron Letters, 2011, 52, 483–487), but the experimental conditions of the reaction were difficult to achieve the yield reported in the literature after repeated repetitions, and symmetrical tetraphenyl dimethyl ether was generated as a byproduct. In fact, it is not difficult to find that one of the reasons behind the low yield of the product under these conditions is that the ester substrate and zinc chloride catalyst selected in this experiment are extremely sensitive to water, so they must be carried out in a strictly anhydrous and oxygen-free glove box.

[0004]

[0005] Some researchers have reported that pentaphenyl dimethyl ether can be synthesized in ionic liquids (Synthetic Communications, 2009, 39, 21, 3785-3795), but this method still produces a large amount of symmetrical tetraphenyl dimethyl ether as a byproduct.

[0006]

[0007] In addition, many researchers have tried to use primary alcohols or secondary alcohols as substrates, and use some metal catalysts (such as ruthenium catalysts) to react with polyaryl tertiary alcohols to generate asymmetric polyaryl ether products. However, when primary alcohols or secondary alcohols with aromatic groups react with polyaryl tertiary alcohols, the activity of primary alcohols or secondary alcohols is much greater than that of tertiary alcohols, so primary alcohols or secondary alcohols are more likely to react with themselves to generate symmetrical polyaryl ether compounds.

[0008]

[0009] In summary, the number of known asymmetric polyaryl ether synthesis methods is limited, or the reaction conditions require the use of metal catalysts, or the reaction conditions are extremely harsh, or it is easy to generate symmetrical ether byproducts that are difficult to separate, resulting in difficulty in purification, or poor yield. According to the principle of atom economy, the most efficient, ideal, and green synthesis route of asymmetric polyaryl ethers should be that the active trityl carbon cation directly reacts with the oxygen-bearing part at the other end. This eliminates the interference of symmetrical ether byproducts with similar polarity of the compounds and realizes full utilization of the raw materials. However, in the existing synthesis methods, such a metal-free and simple asymmetric polyaryl ether synthesis route has not been found. Summary of the invention

[0010] In view of the problems existing in the prior art, namely, the number of known synthesis methods of asymmetric polyaryl ethers is limited, or the reaction conditions require the use of metal catalysts, or the reaction conditions are extremely harsh, or symmetrical ether by-products that are difficult to separate are easily generated, resulting in difficulty in purification, or the yield is poor, the present invention provides a highly selective, metal catalyst-free, efficient preparation method for asymmetric polyaryl ether cluster luminescent materials.

[0011] The preparation method has the advantages of a simple one-step reaction, no strict anhydrous and oxygen-free environment, and a high reaction yield (greater than 80%). Figure 1 shown.

[0012] The present invention is achieved through the following technical solutions:

[0013] A method for preparing an asymmetric polyarylether cluster luminescent material, wherein the asymmetric polyarylether cluster luminescent material has a structure shown in Formula 1 or Formula 2:

[0014]

[0015] In the formula, R is H, an electron donating group or an electron withdrawing group; the electron donating group is dimethylamino, methoxy or diphenylamino; the electron withdrawing group is halogen, cyano, trifluoromethyl or nitro;

[0016] Using 1,8-diazabicycloundec-7-ene to attack triphenylmethane to form a trityl carbon cation, and the trityl carbon cation reacts with an alcohol substrate to obtain the asymmetric polyaryl ether cluster luminescent material;

[0017] The alcohol substrate has a structure as shown in Formula 3 or Formula 4:

[0018]

[0019] The preparation method provided by the present invention is a method for efficiently synthesizing asymmetric polyaryl ether cluster luminescent materials. The preparation method uses a specific organic strong base (1,8-diazabicycloundec-7-ene) to attack triphenylmethane to form a trityl carbon cation, which then reacts with a polyaryl secondary alcohol or primary alcohol substrate, completely avoiding the polyaryl secondary alcohol or primary alcohol substrate from reacting itself to form a symmetrical polyaryl ether compound. The preparation method does not require the control of a strictly anhydrous and oxygen-free environment, does not require other metal catalysts, and has the advantages of being green, economical, simple to react, high selectivity, and high reaction yield (higher than 80%).

[0020] The present invention also provides a more specific method for preparing the asymmetric polyarylether cluster luminescent material, which comprises four steps: feeding, reaction, post-treatment and purification.

[0021] A method for preparing the asymmetric polyarylether cluster luminescent material, the method comprising the following steps:

[0022] (1) feeding: dissolving 1,8-diazabicycloundec-7-ene in an organic solvent, and then adding an alcohol substrate and triphenylmethane to obtain a reaction solution;

[0023] The organic solvent is one of dichloromethane, ethyl acetate, acetone or acetonitrile;

[0024] (2) Reaction: Heat the resulting reaction solution to 45-60° C. and stir to react for 10-12 hours;

[0025] Reaction formula 1 is:

[0026]

[0027] Reaction formula 2 is:

[0028]

[0029] (3) Post-treatment: quench, collect the organic phase, wash, filter, and concentrate in vacuo to obtain the crude product;

[0030] (4) Purification: Purify the obtained crude product by column chromatography and recrystallize to obtain the asymmetric polyaryl ether cluster luminescent material.

[0031] In step (1) of the preparation method, the added alcohol substrate will not react by itself to form symmetrical polyaryl ether compounds, which greatly reduces the difficulty of purification; in step (1) of the preparation method, the added catalyst is only cheap DBU, and no other metal catalyst is required, so that high-selectivity preparation can be achieved; in step (2) of the preparation method, the reaction conditions are mild and no very strict deoxygenation is required, so that high-yield preparation can be achieved, and the yield can be further improved by deoxygenation in this step; in step (4) of the preparation method, the final product obtained does not contain symmetrical polyaryl ethers, so the purification is simple, and the final yield is higher than 80%.

[0032] Preferably, in step (1) of the preparation method, the ratio of the amount of the organic solvent, the organic strong base, the alcohol substrate and triphenylmethane is 3.0-4.0 mL: 3.35-4.00 mmol: 1.64 mmol: 2.46-3.00 mmol.

[0033] Preferably, in step (2) of the preparation method, the reaction liquid is subjected to a deoxygenation process and then the reaction is carried out under an inert gas atmosphere.

[0034] In a preferred embodiment, in step (2) of the preparation method, the reaction solution is subjected to a simple deoxygenation process of bubbling with a nitrogen balloon for 3 minutes, and then reacted under an inert gas atmosphere, thereby increasing the yield by about 5%.

[0035] Preferably, in step (3) of the preparation method, the quenching is carried out with a saturated sodium bicarbonate solution.

[0036] Preferably, in step (3) of the preparation method, the organic phase is collected by extraction with dichloromethane or ethyl acetate.

[0037] Preferably, in step (3) of the preparation method, the washing is performed with brine.

[0038] Preferably, in step (3) of the preparation method, the drying is carried out using anhydrous sodium sulfate.

[0039] Preferably, in step (4) of the preparation method, the column chromatography purification is specifically: eluting with ethyl acetate / petroleum ether as eluent (1:100→1:30).

[0040] Preferably, in step (4) of the preparation method, the product is purified by recrystallization using a dichloromethane / petroleum ether mixture; further preferably, in the dichloromethane / petroleum ether mixture, the volume ratio of dichloromethane to petroleum ether is 1:3 to 1:5.

[0041] The present invention also provides a type of ether non-conjugated cluster luminescent material with fluorescent properties and novel structure prepared by the preparation method. The asymmetric polyaryl ether cluster luminescent material emits fluorescence under the excitation of 360-470nm excitation light and can be used as a potential organic functional material.

[0042] The benzene rings of the asymmetric polyarylether cluster luminescent material provided by the present invention are isolated from each other, without traditional valence bond conjugation, and the luminescence principle is cluster luminescence.

[0043] The material provided by the present invention can only obtain a short-wave emission peak attributed to n or π electron groups in a monodisperse state; after forming clusters, a cluster luminescence peak belonging to spatial conjugation will be generated at a long-wave position. The material also exhibits the excitation-dependent luminescence behavior of cluster luminescent materials, that is, within a certain range, as the excitation wavelength increases, the emitted light will gradually red-shift.

[0044] In one embodiment, a 5W handheld 365nm ultraviolet lamp is used to excite the prepared pentaphenyl dimethyl ether crystal material, and strong green fluorescence can be observed.

[0045] The present invention also provides the use of the asymmetric polyaryl ether cluster luminescent material prepared by the preparation method in a luminescent device.

[0046] Compared with the prior art, the present invention has at least the following advantages:

[0047] 1. The present invention provides a novel method for synthesizing asymmetric polyaryl ethers. The method uses a specific organic strong base (1,8-diazabicycloundec-7-ene) to attack triphenylmethane to form a trityl carbon ion, which then reacts with a polyaryl secondary alcohol or primary alcohol substrate, completely avoiding the polyaryl secondary alcohol or primary alcohol substrate from reacting itself to form a symmetrical polyaryl ether compound, thereby greatly reducing the difficulty of purification.

[0048] 2. The preparation method provided by the present invention does not require strict control of anhydrous and oxygen-free environment, does not require metal catalysts, and has the advantages of being green, economical, simple to react, highly selective, and having a high reaction yield (greater than 80%).

[0049] 3. A type of material prepared by the preparation method of the present invention has special fluorescent properties and novel structure, emits fluorescence under the excitation of 360-470nm excitation light, and can be used as a potential organic functional material.

[0050] 4. The preparation method of the present invention is suitable for industrial application, and the prepared material has good application prospects in light-emitting devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A preparation route map of the preparation method provided by the present invention;

[0052] Figure 2 The pentaphenyl dimethyl ether prepared in Example 1 1 H NMR spectrum;

[0053] Figure 3 The pentaphenyl dimethyl ether prepared in Example 1 13 C NMR spectrum;

[0054] Figure 4 The XRD diffraction single crystal structure diagram of pentaphenyl dimethyl ether prepared in Example 1;

[0055] Figure 5 The pentaphenylmethylethyl prepared in Example 2 1 H NMR spectrum;

[0056] Figure 6 The pentaphenylmethylethyl prepared in Example 2 13 C NMR spectrum;

[0057] Figure 7 This is a crystal fluorescence photograph of pentaphenyl dimethyl ether measured in Example 3 (365nm excitation);

[0058] Figure 8 This is the steady-state fluorescence spectrum of pentaphenyl dimethyl ether crystal measured in Example 3 under excitation at 360nm and 370nm. DETAILED DESCRIPTION

[0059] The present invention will be further described below in conjunction with the accompanying drawings and specific examples. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention. The operating methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0060] Example 1

[0061] DBU (509 mg, 0.50 mL, 3.35 mmol) was added to a DCM (3.0 mL) solution at 25°C and stirred. Finally, benzhydrol (302 mg, 1.64 mmol) and triphenylmethane (686 mg, 2.46 mmol) were mixed and added and heated to 45°C. After stirring the reaction at this temperature for 10 h, saturated NaHCO 3 The solution was quenched with 1% paraformaldehyde (20 mL), and the organic phase was collected and extracted with DCM (3×20 mL), washed with brine (20 mL) and dried over anhydrous Na 2 SO 4Dry, filter, and vacuum concentrate to obtain a crude product. Use ethyl acetate / petroleum ether (1:100→1:30) as the eluent and purify by column chromatography to obtain pentaphenyl dimethyl ether as a white powder. The product can be further purified by recrystallization from a mixed solution of dichloromethane / petroleum ether to obtain colorless crystals with a yield of 82%.

[0062] The reaction formula of diphenylmethanol and triphenylmethane is:

[0063]

[0064] Figure 2 The pentaphenyl dimethyl ether prepared in this embodiment 1 H NMR spectrum, Figure 3 The pentaphenyl dimethyl ether prepared in this embodiment 13 C NMR spectrum, Figure 4 This is the XRD diffraction single crystal structure diagram of pentaphenyl dimethyl ether prepared in this example.

[0065] The NMR spectrum data of pentaphenyl dimethyl ether is: 1 H NMR (600MHz, DMSO-d6) δ7.38(d,J=7.2Hz,6H),7.28(d,J=7.4Hz,4H),7.20–7.10(m,13H),7.03(t,J=7.2Hz,2H),5.56(s,1H). 13 CNMR(150MHz,DMSO)δ145.10,144.73,129.05,128.32,128.03,127.39,126.62,126.06,88.61,78.20.

[0066] Example 2

[0067] Using diphenylethanol instead of diphenylmethanol, the other steps were the same as in Example 1 to obtain pentaphenylmethyl ethyl ether with a yield of 70%.

[0068] The reaction formula of diphenylethanol and triphenylmethane is:

[0069]

[0070] Figure 5 The pentaphenyl methyl ethyl ether prepared in this example 1 H NMR spectrum, Figure 6 The pentaphenyl methyl ethyl ether prepared in this example 13 C NMR spectrum.

[0071] The NMR spectrum data of pentaphenyl methyl ethyl ether are: 1 H NMR (600 MHz, CDCl 3)δ7.35–7.11(m,25H),4.22(t,J=6.8Hz,1H),3.64(d,J=6.9Hz,2H). 13 CNMR (150MHz, CDCl 3 )δ144.09,142.68,128.77,128.58,128.24,127.72,126.88,126.33,86.69,77.24,77.03,76.82,67.03,51.46.

[0072] Example 3

[0073] The fluorescence performance of the pentaphenyl dimethyl ether crystal material prepared in Example 1 was tested.

[0074] The experimental method includes the following steps:

[0075] (a) When excited by a 5 W handheld 365 nm UV lamp, strong green fluorescence can be observed.

[0076] (b) Subsequently, the sample (in the form of crystal) was placed in a Thermo Fisher brand UV quartz fluorescence cuvette with four sides transparent to light, and the crystal was excited at UV 360nm and 460nm using a Shimadzu RF-6000 fluorescence spectrophotometer to obtain the fluorescence emission spectrum (the excitation and emission slits were both 10nm).

[0077] Figure 7 This is the crystal fluorescence photograph of pentaphenyl dimethyl ether measured in Example 3 (365nm excitation), Figure 8 This is the steady-state fluorescence spectrum of pentaphenyl dimethyl ether crystal measured in Example 3 under excitation at 360nm and 370nm.

[0078] The prepared non-conjugated pentaphenyl dimethyl ether crystal has a maximum emission peak wavelength of 550nm, has certain excitation dependence and strong solid-state fluorescence emission.

[0079] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A method for preparing an asymmetric polyarylether cluster luminescent material, It is characterized in that The asymmetric polyarylether cluster luminescent material has a structure shown in Formula 1 or Formula 2: In the formula, R is H, an electron donating group or an electron withdrawing group; the electron donating group is dimethylamino, methoxy or diphenylamino; the electron withdrawing group is halogen, cyano, trifluoromethyl or nitro; Using 1,8-diazabicycloundec-7-ene to attack triphenylmethane to form a trityl carbon cation, and the trityl carbon cation reacts with an alcohol substrate to obtain the asymmetric polyaryl ether cluster luminescent material; The alcohol substrate has a structure as shown in Formula 3 or Formula 4:

2. The method for preparing the asymmetric polyarylether cluster luminescent material according to claim 1, It is characterized in that The preparation method comprises the following steps: (1) feeding: dissolving 1,8-diazabicycloundec-7-ene in an organic solvent, and then adding an alcohol substrate and triphenylmethane to obtain a reaction solution; The organic solvent is one of dichloromethane, ethyl acetate, acetone or acetonitrile; (2) Reaction: Heat the resulting reaction solution to 45-60° C. and stir to react for 10-12 hours; (3) Post-treatment: quench, collect the organic phase, wash, filter, and concentrate in vacuo to obtain the crude product; (4) Purification: Purify the obtained crude product by column chromatography and recrystallize to obtain the asymmetric polyaryl ether cluster luminescent material.

3. The method for preparing the asymmetric polyarylether cluster luminescent material according to claim 2, It is characterized in that In step (1), the ratio of the amount of the organic solvent, the organic strong base, the alcohol substrate and triphenylmethane is 3.0-4.0 mL: 3.35-4.00 mmol: 1.64 mmol: 2.46-3.00 mmol.

4. The method for preparing the asymmetric polyarylether cluster luminescent material according to claim 2, It is characterized in that In step (2), the reaction solution is subjected to a deoxygenation process and then the reaction is carried out under an inert gas atmosphere.

5. The method for preparing the asymmetric polyarylether cluster luminescent material according to claim 2, It is characterized in that In step (3): The quenching is performed with a saturated sodium bicarbonate solution; The organic phase was collected by extraction with dichloromethane or ethyl acetate; The washing was done with brine.

6. The method for preparing the asymmetric polyarylether cluster luminescent material according to claim 2, It is characterized in that In step (4), the product is purified by recrystallization using a dichloromethane / petroleum ether mixture; in the dichloromethane / petroleum ether mixture, the volume ratio of dichloromethane to petroleum ether is 1:3 to 1:

5.

7. The method for preparing the asymmetric polyarylether cluster luminescent material according to claim 1, It is characterized in that The prepared asymmetric polyarylether cluster luminescent material is pentaphenyl dimethyl ether, which has fluorescent properties; Pentaphenyl dimethyl ether emits fluorescence under the excitation of 360-470nm excitation light.

8. Application of pentaphenyl dimethyl ether in light-emitting devices.

Images