Metal coordination compound and its application

Abstract

Metal coordination compound, wherein it is a compound with the structure of formula (I): where: R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , and R 10 each are independently selected from the group consisting of hydrogen, deuterium, or alkyl with 1-4 carbon atoms; R 1 , R 6 , R 9 , R 11 , R 12 and R 13each is selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl with 1-6 carbon atoms, substituted or unsubstituted cycloalkyl with 3-6 carbon atoms, substituted or unsubstituted alkoxy with 1-6 carbon atoms, substituted or unsubstituted aryl with 6-12 carbon atoms, substituted or unsubstituted heteroaryl with 3-12 carbon atoms and cyano, wherein the substitution is the substitution by deuterium or alkyl with 1-4 carbon atoms; wherein Ar 1 selected from the following aromatic structures: and where Ar 2 and Ar 3 Each is independently an aromatic group with 5-10 carbon atoms.

Description

Technical area

[0001] The present invention relates to the technical field of organic electroluminescent material, in particular to a metal coordination compound and its application in organic electroluminescent devices as a luminescent material. State of the art

[0002] Organic optoelectronic devices include, but are not limited to, the following categories: organic electroluminescent devices (OLEDs), organic thin-film transistors (OTFTs), organic photovoltaic devices (OPVs), light-emitting electrochemical batteries (LCEs), and chemical sensors.

[0003] In recent years, OLEDs have attracted considerable attention from academia and industry as a promising lighting and display technology. OLED devices have the characteristics of self-luminescence, wide viewing angle, short response time, and the ability to fabricate flexible devices, making them strong competitors for next-generation display and lighting technologies. However, OLEDs currently still have problems such as low efficiency and short lifetime, and require further research.

[0004] Early fluorescent OLEDs typically only utilized the singlet state to emit light, and the triplet excitons generated within the device could not be effectively utilized and would return to the ground state without radiative emission. Therefore, the quantum yield of fluorescent OLEDs is low, limiting the widespread use of OLEDs. In 1998, Zhiming Zhi of the University of Hong Kong first reported the phenomenon of electrophosphorescence. In the same year, Thompson et al. fabricated phosphorescent OLEDs using transition metal coordination compounds as light-emitting materials. Phosphorescent OLEDs can simultaneously utilize singlet and triplet excitons to emit light and achieve an internal quantum efficiency of 100%, which greatly promoted the commercialization of OLEDs.The control of the light emission color of OLEDs can be achieved through the structural design of light-emitting materials. OLEDs can comprise one or multiple light-emitting layers to achieve the desired spectrum. Currently, green, yellow, and red phosphorescent materials are already commercialized. Commercial OLED screens typically use blue fluorescence and yellow or green and red phosphorescence to achieve full-color displays. Light-emitting materials with saturated luminescence spectrums, higher efficiency, and longer lifetimes are urgently needed by the industry.

[0005] Metal coordination compound luminescent materials are already used in industry, but their properties such as color saturation, lifetime, etc., cannot yet meet the requirements. The present invention provides a series of metal coordination compounds, and research has shown that such metal coordination compounds can emit deep-red to near-infrared light. Further research has shown that such coordination compounds also exhibit the property of aggregation-induced luminescence enhancement.

[0006] In the prior art, complexes suitable as organic electroluminescent material are disclosed, for example, in WO 2015 / 149 677 A1. Content of the invention

[0007] In view of the above-described problems in the prior art, the present invention provides a metal coordination compound luminescent material applied to an organic electroluminescent device, which exhibits good optoelectronic properties and a good device lifetime. The present invention further provides an electroluminescent device containing the metal coordination compound of the present invention.

[0008] An organic electroluminescent material is a compound according to claim 1 having the structure of formula (I):wherein: R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , and R 10 are each independently selected from the group consisting of hydrogen, deuterium, alkyl having 1-4 carbon atoms; R 1 , R 6 , R 9 , R 11 , R 12 and R 13each from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1-6 carbon atoms, substituted or unsubstituted cycloalkyl with 3-6 carbon atoms, substituted or unsubstituted alkoxy with 1-6 carbon atoms, substituted or unsubstituted aryl having 6-12 carbon atoms, substituted or unsubstituted heteroaryl having 3-12 carbon atoms and cyano; where the substitution is substitution by deuterium or alkyl having 1-4 carbon atoms; where Ar 2 and Ar 3 each independently represents an aromatic group having 5-10 carbon atoms; and where Ar 1 selected from the following aromatic structures:

[0009] In the general formula (I), Ar 1 further preferably selected from the following aromatic structures:

[0010] In the general formula (I), R 1 , R 6 , R 9 , R 11 , R 12 and R 13 each preferably selected from the group consisting of hydrogen, deuterium, substituted or unsubstituted alkyl having 1-4 carbon atoms and substituted or unsubstituted cycloalkyl having 3-6 carbon atoms.

[0011] In the general formula (I), Ar 2 and Ar 3 preferably the same aromatic group. In the general formula (I), Ar 2 and Ar 3 preferably selected from benzene or naphthalene units.

[0012] Preferred are R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 and R 10 Hydrogen.

[0013] Examples of the metal coordination compound according to the present invention are listed below, but are not limited to the listed structures: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92

[0014] The precursor of the above-mentioned coordination compound, namely the ligand, has the following structural formula:

[0015] The metal coordination compound luminescent material of the present invention can obtain deep red to near-infrared colors when applied to the electroluminescent devices, and the emission wavelength is between 620 nm and 1000 nm, preferably between 630 nm and 900 nm, and more preferably between 630 nm and 800 nm.

[0016] The present invention further provides an application of the above metal coordination compound in organic optoelectronic devices, and the organic optoelectronic devices include, but are not limited to, organic electroluminescent devices (OLEDs), organic thin-film transistors (OTFTs), organic photovoltaic devices (OPVs), light-emitting electrochemical batteries (LCEs), and chemical sensors, preferably OLEDs.

[0017] An organic electroluminescent device (OLEDs) containing the above metal coordination compound, wherein the coordination compound is used as a luminescent material in the luminescent device.

[0018] The organic electroluminescent device in the present invention comprises a cathode, an anode, and an organic layer, wherein the organic layer is one or more of a hole injection layer, a hole transfer layer, a light emitting layer, a hole blocking layer, an electron injection layer, and an electron transfer layer, and it is not desirable for any of these organic layers to be present.

[0019] At least one of the hole-injection layer, the hole-transfer layer, the hole-blocking layer, the light-emitting layer, and / or the electron-transfer layer contains the compound of formula (I). Preferably, the layer containing the compound of structural formula (I) is the light-emitting layer or the electron-transfer layer. The total thickness of the organic layer of the device of the present invention is 1-1000 nm, preferably 1-500 nm, more preferably 5-300 nm. The organic layer can be formed into a thin film by vapor deposition or solution methods. The present invention has the following technical effects: (1) The metal coordination compound in the present invention is used in OLED devices and has good device performance, the luminous efficiency is greatly improved, and the lifetime of the device can be significantly improved; (2) When conventional light-emitting molecules are used in the aggregated state, the luminescence quantum yield is reduced due to the strong intermolecular interaction, and the metal coordination compound in the present invention has the property of aggregation-induced luminescence enhancement in the aggregated state, which is conducive to improving the luminous efficiency of the device. Short description of the drawings Fig. 1 shows a structural diagram of the organic electroluminescent device of the present invention.

[0020] Where 10 stands for the glass substrate, 20 for the anode, 30 for the hole injection layer, 40 for the hole transfer layer, 50 for the light emitting layer, 60 for the hole blocking layer, 70 for the electron transfer layer, 80 for the electron injection layer and 90 for the cathode. Detailed embodiments

[0021] The present invention has no requirement regarding the synthesis method of the material. To describe the present invention in more detail, the following examples are given, but are not limited thereto.

[0022] The raw materials of the compounds of the following formulas are all commercially available. Example 1

[0023] Synthesizing coordination compound 4

[0024] Synthesizing intermediate 4c: Dissolve compound 4a (3.5 g, 19.2 mmol), compound 4b (4.6 g, 23.0 mmol), palladium acetate (0.4 g, 0.2 mmol) and CsF (3.0 g, 20.0 mmol) in a mixed solution of trifluoromethanesulfonic acid (10 ml) and water (30 ml), heat to 60°C and React for 8 hours. After cooling to room temperature, the above reaction liquid was added to water and extracted three times with dichloromethane, and the organic phases were combined. After the organic phase was dried with anhydrous sodium sulfate, the solvent was removed by centrifugation, and the residue was separated by column chromatography to obtain a white solid (4.7 g, yield 71%). ESI-MS (m / z): 339.9 (M+1).

[0025] Remarks: when the reaction is scaled up, the reaction yield decreases significantly.

[0026] Synthesizing compound 4e: Under nitrogen protection, compound 4c (17.0 g, 50.0 mmol) is dissolved in tetrahydrofuran (100 ml), the mixture is cooled to -78°C, then n-butyllithium BuLi (1.2 eq.) is added dropwise, after stirring for 30 min, a tetrahydrofuran solution (30 ml) of compound 4d (17.3 g, 50.0 mmol) is added dropwise to the above solution, after stirring for 30 min, the temperature is raised to room temperature, and The solution is further stirred for 1 h. The above reaction liquid is added to water and extracted three times with dichloromethane, and the organic phases are combined. After the organic phase is dried over anhydrous sodium sulfate, the solvent is removed by centrifugation to obtain a pale yellow solid. The above solid is dissolved in acetic acid (50 ml), concentrated sulfuric acid (4 ml) is added, and the solution is refluxed overnight under nitrogen. After cooling to room temperature, the above reaction liquid is added to water and extracted three times with dichloromethane, and the organic phases are combined. After the organic phase is dried over anhydrous sodium sulfate, the solvent is removed by centrifugation, and the residue is precipitated by column chromatography to obtain a pale yellow solid (18.6 g, yield 63%). ESI-MS (m / z): 588.1 (M+1).

[0027] Synthesizing compound 4f: Under nitrogen protection, compound 4e (5.9 g, 10.0 mmol), o-hydroxyphenylboronic acid (1.6 g, 12.0 mmol), Pd(PPh3)4 (0.6 g, 0.5 mmol), K2CO3 (4.0 g, 30.0 mmol), tetrahydrofuran (50 mL), and water (5 mL) were added sequentially to a Schlenk tube. The mixture was heated to 80°C and reacted for 24 hours. After cooling to room temperature, the above reaction liquid was added to water and extracted three times with dichloromethane, and the organic phases were combined. After the organic phase was dried with anhydrous sodium sulfate, the solvent was removed by centrifugation, and the residue was separated by column chromatography to obtain an off-white solid (4.9 g, yield 81%). ESI-MS (m / z): 600.2 (M-1).

[0028] Synthesizing compound 4g: Under nitrogen protection, compound 4f (4.9 g, 8.1 mmol), bis(pinacolato)diboron (37 mmol, 10.0 mmol), potassium acetate (2.5 g, 25.0 mmol), and Pd(dppf)Cl2 (0.3 g, 0.4 mmol) were dissolved in dioxane (50 mL). The mixture was replaced with nitrogen several times and then heated under reflux for a reaction overnight. After cooling to room temperature, the above reaction liquid was added to water and extracted three times with ethyl acetate, and the organic layers were combined. After the organic layer was dried with anhydrous sodium sulfate, the solvent was removed by centrifugation, and the residue was separated by column chromatography to obtain an off-white solid (4.5 g, yield 85%). ESI-MS (m / z): 648.4 (M-1).

[0029] Synthesizing compound 4h: Under nitrogen protection, compound 4 g (4.2 g, 6.5 mmol), chloro-s-triazine (1.0 g, 8.5 mmol), Pd(PPh3)4 (0.3 g, 0.3 mmol), K2CO3 (1.3 g, 10.0 mmol), tetrahydrofuran (30 mL), and water (5 mL) were added successively to a Schlenk tube. The mixture was heated to 80°C and reacted for 24 hours. After cooling to room temperature, the above reaction liquid was added to water and extracted three times with dichloromethane, and the organic phases were combined. After the organic phase was dried with anhydrous sodium sulfate, the solvent was removed by centrifugation, and the residue was separated by column chromatography to obtain a pale yellow solid (2.4 g, yield 62%). ESI-MS (m / z): 601.3 (M-1). Synthesizing coordination compound 4

[0030] Compound 4h (2.0 g, 3.3 mmol), potassium chloroplatinate (1.7 g, 4.0 mmol), and 250 mL of acetic acid were added to the flask, and the mixture was stirred under nitrogen at reflux for 48 h. After cooling to room temperature, the above reaction liquid was added to water, the crude product was obtained by filtration, and recrystallized to obtain a red solid (2.4 g, yield 90%). ESI-MS (m / z): 796.3 (M+1). Example 2

[0031] Synthesizing coordination compound 29

[0032] Synthesizing compound 29b: The intermediate chloro-s-triazine was replaced with intermediate 29a, and compound 29b was prepared following the synthesis procedure of compound 4h to obtain a pale yellow solid (3.2 g, yield 70%). ESI-MS (m / z): 650.3 (M-1). Synthesizing coordination compound 29

[0033] Intermediate 4h was replaced by intermediate 29b, and following the synthesis procedure of coordination compound 4, coordination compound 29 was prepared to obtain a red solid (2.9 g, yield 85%). ESI-MS (m / z): 845.3 (M+1). Example 3

[0034] Synthesizing coordination inhibitor 32 Synthesizing compound 32b

[0035] The intermediate chloro-s-triazine was replaced with intermediate 32a, and compound 32b was prepared following the synthesis procedure of compound 4h to obtain a pale yellow solid (2.1 g, yield 55%). ESI-MS (m / z): 639.3 (M-1). Synthesizing coordination compound 32

[0036] Intermediate 4h was replaced by intermediate 32b, and coordination compound 32 was prepared following the synthesis procedure for coordination compound 4 to obtain a red solid (2.3 g, yield 81%). ESI-MS (m / z): 834.3 (M+1). Example 4

[0037] Synthesizing coordination compound 36 Synthesizing compound 36b

[0038] The intermediate chloro-s-triazine is replaced by intermediate 32a, and compound 32b is prepared following the synthesis procedure of compound 4h to obtain a pale yellow solid (2.1 g, yield 55%). ESI-MS (m / z): 700.3 (M-1). Synthesizing coordination compound 36

[0039] Intermediate 4h was replaced by intermediate 36b, and coordination compound 36 was prepared following the synthesis procedure for coordination compound 4 to obtain a red solid (1.9 g, yield 65%). ESI-MS (m / z): 895.5 (M+1). Example 5

[0040] Synthesizing coordination compound 54 Synthesizing compound 54b

[0041] The intermediate chloro-s-triazine was replaced with intermediate 54a, and compound 54b was prepared following the synthesis procedure of compound 4h to obtain a pale yellow solid (3.5 g, yield 69%). ESI-MS (m / z): 664.4 (M-1). Synthesizing coordination compound 54

[0042] Intermediate 4h is replaced by intermediate 54b, and following the synthesis procedure of coordination compound 4, coordination compound 54 is prepared to obtain a red solid (1.3 g, yield 81%). ESI-MS (m / z): 859.2 (M+1). Examples 6-10

[0043] Using the coordination compound luminescent material of the present invention, the electroluminescent device is manufactured, the device structure is as shown in Fig. 1 shown.

[0044] First, the transparent conductive ITO glass substrate 10 (with the anode 20 thereon) is washed successively with detergent solution, deionized water, ethanol, acetone, and deionized water, and then treated with oxygen plasma for 30 seconds. Then, a 10 nm thick HATCN is evaporated onto the ITO as the hole injection layer 30. Then, the compound NPB is evaporated to form a 40 nm thick hole transfer layer 40.

[0045] Then, a 20 nm thick light-emitting layer 50 is evaporated on the hole transfer layer, and the light-emitting layer is formed by mixing and doping the coordination compound 4 (Embodiment 6) in Embodiments 1 to 5, the coordination compound 29 (Embodiment 7), the coordination compound 32 (Embodiment 8), the coordination compound 36 (Embodiment 9), or the coordination compound 54 (Embodiment 10) with CBP (95%), respectively.

[0046] Then 10 nm thick BAlq is evaporated onto the light-emitting layer as hole blocking layer 60

[0047] Then, 40 nm thick Alq3 is evaporated onto the hole blocking layer as electron transfer layer 70.

[0048] Finally, 1 nm LiF is deposited as electron injection layer 80 and 100 nm Al as device cathode 90. Comparison example

[0049] Using (pq)2 Ir(acac) instead of the compound of the present invention, the organic luminescent device is prepared according to the same method. The structural formulas of HATCN, NPB, CBP, (pq)2 Ir(acac), Alq3, and BAlq in the device are as follows:

[0050] The device properties of the organic electroluminescent devices in Working Examples 6-10 and the Comparative Example at a current density of 10 mA / cm 2 are listed in Table 1: Table 1 Example Connection Drive voltage Luminous efficacy Device lifetime (LT90) Light color 6 4 0.83 1.6 2.1 Deep red light 7 29 0.83 1.3 2.0 Deep red light 8 32 0.91 1.2 1.5 Deep red light 9 36 0.76 1.3 2.1 Near infrared 10 54 0.82 1.4 1.6 Deep red light Comparison example (pq)2Ir(acac ) 1 1 1 Red light Note: For the performance test of the device, reference is made to the comparative example, and the respective indicators in the comparative example are set to 1; LT90 represents the time required for the brightness of the device to decay to 90% of the initial brightness.

[0051] From the data in Table 1, it can be seen that under the same conditions, the efficiency of the organic electroluminescent devices prepared using the compounds according to the present invention is better than that of the comparative example. Compared with the conventional red light material (pq)2Ir(acac), the metal coordination compound material of the present invention applied to the organic electroluminescent device exhibits a lower operating voltage and a greatly improved device lifetime, and emits deep red or near-infrared light, which better meets the requirements of the display industry for luminescent materials and has a good industrialization prospect. Embodiment 11

[0052] The ratios of the luminescence quantum yield (Φ PMMA / Φ Lösung) Metal coordination compounds 4, 29, 32, 36 and 54 in PMMA thin film and in dichloromethane solution are listed in Table 2: Table 2 Coordination connection 4 29 32 36 54 Φ PMMA / ΦSolution 1.2 1.3 1.6 1.8 1.9 Φ PMMA : Luminescence quantum yield of the coordination compound doped in PMMA (20%); Φ Lösung : Luminescence quantum yield of the coordination compound in the dichloromethane solution (1 x 10 -5 M).

[0053] From the data in Table 2, it can be seen that the quantum yield of the metal coordination compound of the present invention in the aggregated state is higher than that in solution. In the aggregated state of platinum coordination compound material, the luminescence quantum yield is usually low due to the concentration quenching effect. The metal coordination compound of the present invention exhibits the property of aggregation-induced luminescence enhancement, and it is evident that the present invention achieves unexpected effects.

Claims

[1] Metal coordination compound, being a compound having the structure of formula (I):wherein: R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , and R 10 are each independently selected from the group consisting of hydrogen, deuterium, or alkyl having 1-4 carbon atoms; R 1 , R 6 , R 9 , R 11 , R 12 and R 13are each selected from the group consisting of hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1-6 carbon atoms, substituted or unsubstituted cycloalkyl having 3-6 carbon atoms, substituted or unsubstituted alkoxy having 1-6 carbon atoms, substituted or unsubstituted aryl having 6-12 carbon atoms, substituted or unsubstituted heteroaryl having 3-12 carbon atoms and cyano, wherein the substitution is substitution by deuterium or alkyl having 1-4 carbon atoms; wherein Ar 1 is selected from the following aromatic structures:and wherein Ar 2 and Ar 3 each independently represents an aromatic group with 5-10 carbon atoms. [2] Metal coordination compound according to claim 1, wherein in the general formula (I) R 1 , R 6 R 9 , R 11 , R 12 and R 13each selected from the group consisting of hydrogen, deuterium, substituted or unsubstituted alkyl having 1-4 carbon atoms and substituted or unsubstituted cycloalkyl having 3-6 carbon atoms. [3] A metal coordination compound according to claim 1 or 2, wherein Ar 1 selected from the following aromatic structures: [4] Metal coordination compound according to any one of claims 1 to 3, wherein Ar 2 and Ar 3 are the same aromatic group. [5] Metal coordination compound according to claim 4, wherein Ar 2 and Ar 3 selected from benzene or naphthalene moiety groups. [6] Metal coordination compound according to claim 5, wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 and R 10 are hydrogen, and where Ar 2 and Ar 3benzene. [7] Metal coordination compound according to claim 1, having one of the following structural formulas: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 ◦ [8] Precursor of the metal coordination compound according to any one of claims 1 to 7, namely ligand, having the following structural formula: [9] Use of the metal coordination compound according to any one of claims 1 to 7 in the organic optoelectronic devices, wherein the organic optoelectronic devices include organic electroluminescent devices, organic thin-film transistors, organic photovoltaic devices, light-emitting electrochemical batteries and chemical sensors. [10] An organic electroluminescent device comprising a cathode, an anode, and an organic layer, wherein the organic layer is one or more of a hole injection layer, a hole transfer layer, a light emitting layer, a hole blocking layer, an electron injection layer, and an electron transfer layer, wherein the organic layer contains a metal coordination compound according to any one of claims 1 to 7. [11] The organic electroluminescent device according to claim 10, wherein the metal coordination compound according to any one of claims 1 to 7 is in the light-emitting layer or the electron transfer layer. [12] The organic electroluminescent device according to claim 10, wherein the total thickness of the organic layer is 1-1000 nm, and wherein the organic layer is formed into a thin film by vapor deposition or solution methods.

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