PREPARATION OF TETRADENTATE PLATINUM(II) COMPLEX AND USE THEREOF

Abstract

The present invention relates to the preparation of a novel tetradentate platinum (II) complex and an application thereof, belonging to the field of OLED organic electroluminescent materials. The complex of the present invention has the following structural formula, and is used for a phosphorescent doping material having a photon emission effect in a light-emitting layer of an OLED luminescent device. The complex of the present invention has a high fluorescence quantum efficiency, a good heat stability and a low quenching constant, and can be used for the manufacture of a green light OLED device with a high luminous efficiency and low roll-off.

##STR00001##

Claims

1. A tetradentate platinum (II) complex, having a structure as shown in the following formula: ##STR00025## wherein R.sub.1—R.sub.21 are independently selected from hydrogen, deuterium, sulfur, halogen, hydroxy, acyl, alkoxy, acyloxy, amino, nitro, acylamino, cyano, carboxyl, styryl, aminocarbonyl, carbamoyl, benzylcarbonyl, aryloxy, diarylamino, saturated alkyl containing 1-30 C atoms, unsaturated alkyl containing 2-20 C atoms, substituted or unsubstituted aryl containing 5-30 C atoms, substituted or unsubstituted heteroaryl containing 5-30 C atoms, or adjacent R.sub.1—R.sub.21 are mutually linked to form a ring via a covalent bond, wherein the substitution refers to a substitution by halogen, deuterium, C1-C20 alkyl, C1-C10 silicyl, and cyano; and heteroatom in the heteroaryl is one or more of N, O and S.

2. The complex according to claim 1, wherein R.sub.1—R.sub.21 are independently selected from hydrogen, halogen, amino, nitro, cyano, diarylamino, saturated alkyl containing 1-10 C atoms, aryl substituted by halogen or one or more C1-C4 alkyl and containing 5-20 C atoms or unsubstituted aryl containing 5-20 C atoms, heteroaryl substituted by halogen or one or more C1-C4 alkyl and containing 5-20 C atoms or unsubstituted heteroaryl containing 5-20 C atoms, or adjacent R.sub.1—R.sub.21 are mutually linked to form a ring via a covalent bond; and the halogen is F, Cl, Br.

3. The complex according to claim 2, wherein in the 21 groups of the R.sub.1-R.sub.21, 0-3 groups independently represent diarylamino, aryl substituted by halogen or one to three C1-C4 alkyl and containing 5-10 C atoms or unsubstituted aryl containing 5-10 C atoms, N-bearing heteroaryl substituted by halogen or one to three C1-C4 alkyl and containing 5-10 C atoms or unsubstituted N-bearing heteroaryl containing 5-10 C atoms; other groups independently represent hydrogen or saturated alkyl containing 1-8 C atoms; and the halogen is F, Cl.

4. The complex according to claim 3, wherein in the 21 groups of the R.sub.1-R.sub.21, 0-3 groups independently represent diphenylamino, phenyl, pyridyl, carbazolyl; and other groups independently represent hydrogen, fluorine or saturated alkyl containing 1-4 C atoms.

5. The complex according to claim 1, having a structure as shown in the following formula: ##STR00026## wherein R.sub.1′-R.sub.6′ are independently selected from hydrogen, halogen, diarylamino, saturated alkyl containing 1-10 C atoms, aryl substituted by halogen or one or more C1-C4 alkyl and containing 5-20 C atoms or unsubstituted aryl containing 5-20 C atoms, heteroaryl substituted by halogen or one or more C1-C4 alkyl and containing 5-20 C atoms or unsubstituted heteroaryl containing 5-20 C atoms, or adjacent R.sub.1′-R.sub.6′ are mutually linked to form a ring via a covalent bond; the halogen is F, Cl, Br; and heteroatom in the heteroaryl is any one of N, O and S.

6. The complex according to claim 5, wherein in the 6 groups of the R.sub.1′-R.sub.6′, 0-3 groups independently represent diarylamino, aryl substituted by halogen or one to three C1-C4 alkyl and containing 5-10 C atoms or unsubstituted aryl containing 5-10 C atoms, heteroaryl substituted by halogen or one to three C1-C4 alkyl and containing 5-10 C atoms or unsubstituted heteroaryl containing 5-10 C atoms; other groups independently represent hydrogen, halogen or saturated alkyl containing 1-8 C atoms; and the halogen is F, Cl.

7. The complex according to claim 1, wherein in the 6 groups of the R.sub.1′-R.sub.6′, 0-3 groups independently represent diphenylamino, C1-C4 alkyl substituted or unsubstituted phenyl, pyridyl, carbazolyl; and other groups independently represent hydrogen, fluorine or saturated alkyl containing 1-4 C atoms.

8. The complex according to claim 1, having a structure below: ##STR00027## ##STR00028## ##STR00029## ##STR00030## ##STR00031## ##STR00032## ##STR00033## ##STR00034## ##STR00035## ##STR00036##

9. A precursor of the complex of any one of claims 1-8, namely, a ligand, having a structural formula below: ##STR00037## wherein R.sub.1—R.sub.21 are independently selected from hydrogen, deuterium, sulfur, halogen, hydroxy, acyl, alkoxy, acyloxy, amino, nitro, acylamino, cyano, carboxyl, styryl, aminocarbonyl, carbamoyl, benzylcarbonyl, aryloxy, diarylamino, saturated alkyl containing 1-30 C atoms, unsaturated alkyl containing 2-20 C atoms, substituted or unsubstituted aryl containing 5-30 C atoms, substituted or unsubstituted heteroaryl containing 5-30 C atoms, or adjacent R.sub.1-R.sub.21 are mutually linked to form a ring via a covalent bond, wherein the substitution refers to a substitution by halogen, deuterium, C1-C20 alkyl, C1-C10 silicyl, and cyano; and heteroatom in the heteroaryl is one or more of N, O and S.

10. A synthesis method for the tetradentate platinum (II) complex according to claim 5, comprising the following steps: subjecting initial substrates S1 and S2 to Suzuki-Miyaura coupling reaction to obtain a substrate S3; subjecting the S3 and S4 to Buchwald-Hartwig coupling reaction to obtain a substrate S5; then subjecting the S5 and S6 to Buchwald-Hartwig coupling reaction to obtain a substrate S7, heating the S7 at a high temperature under the action of a pyridine hydrochloride for demethylation to obtain an S8; performing a chelation reaction on the S8 and K.sub.2PtCl.sub.4 to obtain a target platinum (II) complex TM, ##STR00038##

11. An application of the complex of any one of claims 1-8 in an OLED luminescent device.

12. The application according to claim 9, wherein the complex of any one of claims 1-8 serves as a phosphorescent doping material having a photon emission effect in a light-emitting layer.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0042] FIG. 1 is a structure diagram showing an organic light-emitting device in the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0043] The present invention will be further described specifically in combination with the examples below.

[0044] The preparation of the above complex includes the following steps: [0045] as shown below, subjecting initial substrates S1 and S2 to Suzuki-Miyaura coupling reaction to obtain a substrate S3; subjecting the S3 and S4 to Buchwald-Hartwig coupling reaction to obtain a substrate S5; then subjecting the S5 and S6 to Buchwald-Hartwig coupling reaction to obtain a substrate S7, heating the S7 at a high temperature under the action of a pyridine hydrochloride for demethylation to obtain an S8; performing a chelation reaction on the S8 and K.sub.2PtCl.sub.4 to obtain a target platinum (II) complex TM.

##STR00015##

[0046] Initial substrates, intermediates, solvents and the like related in the compound synthesis of the present invention are purchased from Energy Chemical, J&K Chemicals, aladdin and other suppliers known well by a person skilled in the art.

EXAMPLE 1

[0047] ##STR00016##

[0048] Synthesis of the compound 3: 20.0 g (0.10 mol) compound 1, 19.8 g (0.125 mol) compound 2, 3.46 g (0.03 eq., 3.0 mmol) tetrakis(triphenylphosphine)palladium, and 27.6 g (2.0 eq., 0.20 mol) potassium carbonate were taken and put to a flask, and added with 210 mL dioxane and 60 mL water, and heated for reflux reaction for 8 h under the protection of nitrogen. After stopping the reaction, the system was cooled to room temperature and subjected to rotary evaporation to remove the solvent; a proper amount of water and ethyl acetate were added for extraction, organic phases were collected and dried, after removing the solvent by rotary evaporation, a flash silica gel column (mobile phase n-hexane/ethyl acetate=10:1) was used for separation and recrystallization, thus obtaining 20.0 g of a target product compound 3 with a yield of 85% and a purity of 99.9%.

[0049] Synthesis of the compound 5: 11.7 g (50 mmol) compound 3, 9.3 g (50 mmol) compound 4, 450 mg (0.04 eq., 2 mmol) palladium acetate, 0.40 g (0.08 eq., 4 mmol) tri-tert-butylphosphine and 11.22 g (2.0 eq., 0.10 mol) potassium tert-butoxide were taken and put to a flask, and added with 200 mL toluene, and heated for reflux reaction for 8 h under the protection of nitrogen. After stopping the reaction, the system was cooled to room temperature and subjected to rotary evaporation to remove the solvent; a proper amount of water and ethyl acetate were added for extraction, organic phases were collected and dried, after removing the solvent by rotary evaporation, a flash silica gel column (mobile phase n-hexane/ethyl acetate=15:1) was used for separation and recrystallization, thus obtaining 23.83 g of a target product compound 5 with a yield of 88% and a purity of 99.9%.

[0050] Synthesis of the compound 7: 4.9 g (20 mmol) compound 5, 7.9 g (20 mmol) compound 6, 225 g (0.02 eq., 1 mmol) palladium acetate, 0.20 g (0.04 eq., 2 mmol) tri-tert-butylphosphine, and 4.5 g (2.0 eq., 0.04 mol) potassium tert-butoxide were taken and put to a flask, and added with 100 mL toluene, and heated for reflux reaction for 8 h under the protection of nitrogen. After stopping the reaction, the system was cooled to room temperature and subjected to rotary evaporation to remove the solvent; a proper amount of water and ethyl acetate were added for extraction, organic phases were collected and dried, after removing the solvent by rotary evaporation, a flash silica gel column (mobile phase n-hexane/ethyl acetate=10:1) was used for separation and recrystallization, thus obtaining 8.9 g of a target product compound 7 with a yield of 75% and a purity of 99.9%.

[0051] Synthesis of the compound 8: 5.9 g (10 mmol) compound 7 and 50 g pyridine hydrochloride were taken and heated up to 200° C. for 8 h under the protection of nitrogen.

[0052] After stopping the reaction, a proper amount of water and ethyl acetate were added for extraction, organic phases were collected and dried, after removing the solvent by rotary evaporation, a flash silica gel column (mobile phase n-hexane/ethyl acetate=15:1) was used for separation and methanol was used for recrystallization, thus obtaining 5.0 g of a target product compound 8 with a yield of 86% and a purity of 99.9%. Theoretical values of mass spectrometry (ESI.sup.-) ([M-H].sup.−) C.sub.41H.sub.27N.sub.3O: 576.22; measured value: 576.21.

[0053] Synthesis of the compound Pt-1: 1.15 g (2.0 mmol) compound 8, 160 mg tetrabutylammonium bromide (0.25 eq., 0.5 mmol) and 930 mg (1.2 eq., 2.4 mmol) potassium tetrachloroplatinate were taken and dissolved into 50 mL acetic acid, and vacuumized and fed nitrogen for replacement for several times, stirred and heated up to 130° C. for reaction for 12 h. After stopping the reaction, the system was cooled to remove the solvent by rotary evaporation; a proper amount of water and ethyl acetate were added for extraction, organic phases were collected and dried by anhydrous magnesium sulfate, then subjected to rotary evaporation to remove the solvent, and a flash silica gel column (mobile phase n-hexane/dichloromethane=10:1) was used for separation and methanol was used for recrystallization, and the obtained coarse product was sublimated in vacuum, thus obtaining 616 mg of a red solid with a yield of 40% and a purity of 99.95%. Theoretical values of mass spectrometry (ESI-) ([M-H].sup.−) C.sub.41H.sub.25N.sub.3OP.sub.t: 771.16; measured value: 771.19.

EXAMPLE 2

[0054] ##STR00017##

[0055] The preparation method of Pt-2 is the same as the synthetic route of Pt-1, and the only difference is that the compound 4 is replaced with the compound 9. The compound 9 has the following molecular formula:

##STR00018##

##STR00019##

EXAMPLE 3

[0056] The preparation method of Pt-3 is the same as the synthetic route of Pt-1, and the only difference is that the compound 4 is replaced with the compound 9, and the compound 6 is replaced with the compound 10. The compound 10 has the following molecular formula:

##STR00020##

EXAMPLE 4

[0057] ##STR00021##

[0058] The preparation method of Pt-12 is the same as the synthetic route of Pt-1, and the only difference is that the compound 2 is replaced with the compound 11, and the compound 4 is replaced with the compound 12, and the compound 6 is replaced with the compound 10. The compound 11 has the following molecular formula:

##STR00022##

[0059] The application example of the compound in the present invention is as follows: [0060] ITO/TAPC (70 nm)/TCTA:Pt(II) (40 nm)/TmPyPb (30 nm)/LiF (1 nm)/Al (90 nm)

[0061] Preparation mode of the device:

[0062] A transparent anode, indium tin oxide (ITO) (10 Q/sq) glass substrate was subjected to ultrasonic cleaning with acetone, ethanol and distilled water successively, and then subjected to plasma treatment with oxygen gas for 5 min.

[0063] The ITO substrate was then mounted on a substrate holder of a vacuum gas-phase evaporation equipment. In the evaporation equipment, the system pressure was controlled 10-6 torr.

[0064] Afterwards, a hole transport layer (HTL) material TAPC having a thickness of 70 nm was evaporated on the ITO substrate.

[0065] A light-emitting layer material (EML) TCTA having a thickness of 40 nm was then evaporated, where the platinum (II) complex having a mass fraction of 10% was doped.

[0066] An electron transfer layer (ETL) material TmPyPb having a thickness of 30 nm was then evaporated.

[0067] An electron injection layer (EIL) having a thickness of 1 nm was then evaporated.

[0068] Finally, Al having a thickness of 90 nm was evaporated as a cathode and device packaging was completed. As shown in FIG. 1

##STR00023##

[0069] The devices STD, 1, 2, 3 and 4 are successively prepared; the device structure and manufacture method are basically completely the same; the difference is that the platinum (II) complexes STD, Pt-1, Pt-2, Pt-3 and Pt-12 successively serve as dopants in the light-emitting layer. The reference material STD is a typical green emitting material having an ONCN coordination structure.

##STR00024##

[0070] Comparison results of the devices are shown in Table 1. With the performance of the device STD as standards, - represents holding the standard line; -- represents reduction by 5% above relative to the standard performance; +represents promotion by 5% relative to the standard performance; ++represents promotion by 10% relative to the standard performance.

TABLE-US-00001 Device 1 Device 2 Device 3 Device 4 Maximum external + + ++ ++ quantum efficiency External quantum efficiency + + + ++ below 100 nit Initial voltage — — — — Current efficiency + + + ++ below 100 nit

[0071] It can be seen from the above table that relative to the reference device, the organic light-emitting device prepared on the basis of the platinum (II) complex of the present invention has improved performance at different levels. Such kind of novel Pt (II) complex has strong molecular tridimensional property and weak molecular interaction, thus avoiding molecular stacking of the complex, inhibiting the formation of an excimer to the maximum extent, and improving the efficiency of the OLED device. To sum up, relative to the reference device, the organic light-emitting device prepared by the present invention has better improvement in performance; and the related novel tetradentate platinum (II) complex metal organic material has greater application values.