CN112500394A

CN112500394A - Four-ring metal carbene-palladium deep blue light phosphorescent material and application thereof

Info

Publication number: CN112500394A
Application number: CN202011478915.5A
Authority: CN
Inventors: 李贵杰; 佘远斌; 郑建兵; 周春松
Original assignee: Zhejiang University of Technology ZJUT
Current assignee: Zhejiang University of Technology ZJUT
Priority date: 2020-12-15
Filing date: 2020-12-15
Publication date: 2021-03-16
Anticipated expiration: 2040-12-15
Also published as: CN112500394B

Abstract

The invention discloses a four-ring metal carbene-palladium complex deep blue light luminescent material, which has any one of the following structures (I) to (VIII):

wherein Ph/NHC represents benzocarbene; Ph-NHC represents 4-phenylcarbene; Py/NHC represents pyridocarbene. The organic luminescent material is a deep blue luminescent material with high thermal stability and high color purity, and has great application prospect in the field of OLED materials.

Description

Four-ring metal carbene-palladium deep blue light phosphorescent material and application thereof

Technical Field

The invention belongs to the technical field of organic photoelectric materials, and particularly relates to a four-toothed-ring metal carbene-palladium complex deep blue light luminescent material which can be used in the fields of OLED display and illumination.

Background

The Organic Light Emitting Diode (OLED) has wide application prospect in the fields of illumination and display due to the characteristics of energy conservation, high response speed, high resolution, wide viewing angle, high contrast and the like. Since the OLED can take flexible plastic as a substrate, the OLED can be further developed into a flexible display technology and is used in the military field; in addition, the application temperature range is wide, and the method has a huge application prospect in the field of aerospace. Therefore, it is widely regarded by academic and industrial fields.

The color gamut refers to a range region of colors that can be expressed by a certain color representation mode, and also refers to a range of colors that can be expressed by a specific device, such as a display, a printer, etc., for printing and copying. The larger the gamut space of the device, the more colors it is able to reproduce. The National Television Standards Committee (NTSC) specifies that the chromaticity coordinates of "pure blue light" on CIE1931 are (0.14, 0.08). With the development of the display industry, the color gamut of the display industry is also getting larger, and the first version of the (UHD 4K) high definition television standard, abbreviated as bt.2020, is published on the International Telecommunications Union (ITU) website at 8/23/2012; and aspects of High Dynamic Range (HDR) video, abbreviated bt.2100, were defined in 2016, 7, month, 4. The chromaticity coordinates of the blue light of bt.2020 and bt.2100 on CIE1931 are both (0.131, 0.046), which is a deep blue region (see fig. 1). Higher requirements are put on the light-emitting color of the blue light-emitting material. Phosphorescent light emitting materials are central to the development of the OLED field. The chromaticity coordinate y value of the blue phosphorescent luminescent material which is developed at present is generally between 0.10 and 0.20, and is between blue light and sky blue light. Therefore, how to emit blue light, especially, how to satisfy the requirement of the display field for the continuously expanded color gamut range by using the deep blue light emitting material with the CIE1931 chromaticity coordinate y value less than 0.10 is one of the problems to be solved in the field.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a four-toothed-ring metal carbene palladium complex deep blue light luminescent material which can be used in the fields of OLED display and illumination.

In order to achieve the purpose, the invention adopts the following technical scheme: a four-ring metal carbene-palladium deep blue light phosphorescent material is characterized in that the structure of the deep blue light phosphorescent material is any one of (I) to (VIII):

wherein Ph/NHC represents benzocarbene; Ph-NHC represents 4-phenylcarbene; Py/NHC represents pyridocarbene.

The invention also provides application of the four-toothed ring metal carbene palladium deep blue light phosphorescent material in a light-emitting layer of an organic electroluminescent device.

The invention also provides an optical device which comprises one or more of the four-toothed ring metal carbene-palladium deep blue phosphorescent materials.

Compared with the prior art, the invention has the beneficial effects that: according to the four-ring metal carbene-palladium complex deep blue light luminescent material, the 4-alkyl of pyridine can narrow the emission spectrum and improve the color purity of the emitted light; and the alkyl substituent of the benzene ring can avoid the accumulation of pi-pi among molecules, is beneficial to the purification of material molecules through vacuum sublimation and can improve the thermal stability of the material molecules. The deep blue light luminescent material is a deep blue light luminescent material with high thermal stability and high color purity, and has great application prospect in the field of OLED materials.

Drawings

FIG. 1 is a graph showing the emission spectra of the luminescent material PtON5-mm in 2-methyltetrahydrofuran at 77K, dichloromethane at room temperature and polymethyl methacrylate film at room temperature; wherein 2-MeTHF is 2-methyltetrahydrofuran, DCM is dichloromethane PMMA is polymethyl methacrylate, and RT represents room temperature;

FIG. 2 is a graph showing the emission spectra of the luminescent material PtON5-mi in 2-methyltetrahydrofuran at 77K, in a dichloromethane solution at room temperature, and in a polymethyl methacrylate film at room temperature; wherein 2-MeTHF is 2-methyltetrahydrofuran, DCM is dichloromethane PMMA is polymethyl methacrylate, and RT represents room temperature;

FIG. 3 is a graph showing the emission spectra of the luminescent material PtON5-mt in 2-methyltetrahydrofuran at 77K, in a dichloromethane solution at room temperature, and in a polymethyl methacrylate film at room temperature; wherein 2-MeTHF is 2-methyltetrahydrofuran, DCM is dichloromethane PMMA is polymethyl methacrylate, and RT represents room temperature;

FIG. 4 is a graph showing the emission spectra of the luminescent material PtON5-ti in 2-methyltetrahydrofuran at 77K, in a dichloromethane solution at room temperature, and in a polymethylmethacrylate film at room temperature; wherein 2-MeTHF is 2-methyltetrahydrofuran, DCM is dichloromethane PMMA is polymethyl methacrylate, and RT represents room temperature;

FIG. 5 is a graph showing the emission spectra of the luminescent material PtON5-tt in 2-methyltetrahydrofuran at 77K, in a dichloromethane solution at room temperature, and in a polymethylmethacrylate film at room temperature; wherein 2-MeTHF is 2-methyltetrahydrofuran, DCM is dichloromethane PMMA is polymethyl methacrylate, and RT represents room temperature;

FIG. 6 is a graph showing the emission spectra of the luminescent material PtON7p-mt in 2-methyltetrahydrofuran at 77K, in a dichloromethane solution at room temperature, and in a polymethyl methacrylate film at room temperature; wherein 2-MeTHF is 2-methyltetrahydrofuran, DCM is dichloromethane PMMA is polymethyl methacrylate, and RT represents room temperature;

FIG. 7 is a graph showing the emission spectra of the luminescent material PtON7p-tt in 2-methyltetrahydrofuran at 77K, in a dichloromethane solution at room temperature, and in a polymethylmethacrylate film at room temperature; wherein 2-MeTHF is 2-methyltetrahydrofuran, DCM is dichloromethane PMMA is polymethyl methacrylate, and RT represents room temperature;

FIG. 8 is a graph showing the emission spectra of the luminescent material PtON5N-tt in 2-methyltetrahydrofuran at 77K, in a dichloromethane solution at room temperature, and in a polymethylmethacrylate film at room temperature; wherein 2-MeTHF is 2-methyltetrahydrofuran, DCM is dichloromethane PMMA is polymethyl methacrylate, and RT represents room temperature;

FIG. 9 is a thermogravimetric analysis plot of the luminescent material PtON5N-tt with a 5 wt% mass loss temperature of 416 ℃;

FIG. 10 shows a single crystal structure and a molecular stacking diagram of the light-emitting material PtON 5-mi;

FIG. 11 is a LUMO +1, LUMO, HOMO-1, and triplet spin profiles, and the orbital levels of LUMO +1, LUMO, HOMO, and HOMO-1, for the light-emitting materials PtON5-mm, PtON5-mi, PtON5-mt, PtON5-tt, PtON7p-tt, and PtON 5N-tt; wherein Spin Density(T₁) Represents the lowest triplet spin;

FIG. 12 is an electrochemical spectrum of the luminescent materials PtON5-tt, PtON7p-tt and PtON5N-tt in N, N-dimethylformamide at room temperature; wherein ferrocene (Fc) is used as an internal standard, the abscissa is Potential (Potential), and the ordinate is current intensity;

FIG. 13 is an absorption spectrum of the luminescent materials PtON5-tt, PtON7p-tt and PtON5N-tt in dichloromethane at room temperature;

FIG. 14 is a schematic structural diagram of an organic light emitting device;

FIG. 15 is an electroluminescence spectrum of an OLED device made with PtON5N-tt as the light-emitting material.

Detailed Description

The following examples, which are merely exemplary of the present disclosure and are not intended to limit the scope thereof, provide those of ordinary skill in the art with a description of how to make and evaluate the compounds described herein and their OLED devices. Although efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), some errors and deviations should be accounted for. Unless otherwise specified, temperature is in units of ° c or at ambient temperature, and pressure is at or near atmospheric pressure.

The methods described in this example for the preparation of the disclosed compounds described herein are one of many and many others are possible and are not intended to limit the scope of the present application. Thus, one of skill in the art to which this disclosure pertains may readily modify the methods described or utilize different methods for preparing one or more of the disclosed compounds. The following methods are exemplary only, and the temperature, catalyst, concentration, reactant composition, and other process conditions may be varied, and one skilled in the art to which this disclosure pertains may readily select appropriate reactants and conditions for the preparation of the desired compound.

Performed on a Varian Liquid State NMR instrument¹H and¹³c NMR spectrum test. The solvent is CDCl₃Or DMSO-d₆. If the internal standard tetramethylsilane exists in the solvent, the chemical shift isReference tetramethylsilane (δ ═ 0.00 ppm); otherwise, if CDCl is used₃Is a solvent, and is prepared by mixing the components,¹chemical shifts of H NMR spectra were referenced to residual solvent (δ 7.26ppm),¹³chemical shifts of C NMR spectra were referenced to residual solvent (δ 77.00 ppm); if DMSO-d is used₆Is a solvent, and is prepared by mixing the components,¹chemical shift of H NMR spectrum is compared with residual solvent H₂O(δ＝3.33ppm)，¹³Chemical shift of C NMR spectrum is compared with that of residual solvent DMSO-d₆(δ 39.52 ppm). The nuclear magnetic data in the examples are explained using the following abbreviations (or combinations thereof)¹Multiplicity of H NMR: s is singleplex, d is doublet, t is triplet, q is quartet, p is quintuple, m is multiplet, br is wide.

Example 1: the luminescent material PtON5-mm can be synthesized according to the following route:

(1) synthesis of intermediate 3-mm: to a dry three-necked flask with a magnetic stirrer was added 1-m (2.74g,10.00mmol,1.0 equivalent), 2-m (3.45g,12.00mmol,1.2 equivalent), cuprous iodide (190mg,1.00mmol,10 mol%), 2-picolinic acid (246mg,2.00mmol,20 mol%) and potassium phosphate (4.25g,20.00mmol,2.0 equivalent) in that order, followed by purging nitrogen three times and adding dimethyl sulfoxide (40mL) under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, extracted by adding ethyl acetate, the organic layer was washed twice with water and the aqueous layer was extracted twice with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/ethyl acetate 10:1-3:1 gave the product 3-mm as a brown solid 4.10g, 85% yield.¹H NMR(500MHz,CDCl₃):δ2.40(s,3H),2.47(s,3H),6.89(s,1H),7.01(d,J＝1.5Hz,2H),7.07(dd,J＝8.5,2.5Hz,1H),7.12(dd,J＝5.5Hz,1.0Hz,1H),7.29-7.34(m,3H),7.41-7.44(m,2H),7.53-7.57(m,1H),7.52(d,J＝2.0Hz,1H),7.76(d,J＝8.0Hz,1H),7.82-7.86(m,1H),8.09(t,J＝8.0Hz,3H),8.54(d,J＝5.0Hz,1H)。HRMS(ESI):C₃₂H₂₅N₄O[M+H]⁺Calculated 481.2023, found 481.2031.

(2) Synthesis of ligand LON 5-mm: to a dry lock with magnetic stirring was added 3-mm (3.40g,7.07mmol,1.0 equiv.), followed by purging nitrogen three times and addition of toluene (68mL) and methyl iodide (1.20g,8.48mmol,1.2 equiv.) under nitrogen. The mixture was stirred in an oil bath at 100 ℃ for 2 days, cooled to room temperature, filtered, the filtrate rinsed with petroleum ether, dried, the resulting grey solid added to methanol/water (68mL/6.8mL), after dissolution with stirring ammonium hexafluorophosphate (1.73g,10.61mmol,1.5 eq.) was added and the reaction stirred at room temperature for 3 days. Adding water, evaporating most of methanol under reduced pressure, filtering, washing with water, washing with petroleum ether, and drying to obtain gray solid 2.41g with yield of 53%.¹H NMR(500MHz,CDCl₃):δ2.40(s,3H),2.47(s,3H),4.15(s,3H),7.01(s,1H),7.04-7.07(m,2H),7.13(d,J＝4.5Hz,1H),7.19(s,1H),7.29(t,J＝7.5Hz,1H),7.39-7.42(m,2H),7.57-7.65(m,3H),7.67-7.73(m,3H),8.04(d,J＝7.5Hz,1H),8.08(d,J＝8.5Hz,1H),8.50(d,J＝4.5Hz,1H),9.19(s,1H)。¹³C NMR(125MHz,CDCl₃):21.15,21.34,33.56,103.30,110.84,110.91,113.21,113.28,113.46,119.47,119.63,119.93,120.25,121.11,121.39,122.98,123.68,125.88,127.64,127.85,131.07,131.94,133.39,139.99,140.59,140.69,143.05,149.24,150.44,151.23,154.12,159.70。HRMS(ESI):C₃₃H₂₇N₄O[M]⁺Calculated 495.2179, found 495.2188.

(3) Synthesis of PdON 5-mm: to a sealed tube with a magnetic stirrer was added the ligand LON5-mm (200mg,0.31mmol,1.0 equiv.), palladium acetate (77mg,0.34mmol,1.10 equiv.) and potassium carbonate (129mg,0.93mmol,3.0 equiv.) in that order, then nitrogen was purged three times and dioxane (15mL) was added under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/dichloromethane 10:1-3:1 gave the product PdON5-mm as a white solid 101mg, yield 54%.¹H NMR(500MHz,DMSO-d₆):δ2.52(s,3H),2.54(s,3H),4.14(s,3H),6.92(s,1H),7.23-7.25(m,2H),7.44(t,J＝8.0Hz,1H),7.52-7.61(m,3H),7.64(s,1H),7.86-7.88(m,1H),7.96(d,J＝8.0Hz,1H),7.99(s,1H),8.15(d,J＝8.0Hz,1H),8.20(d,J＝7.5Hz,1H),8.49(d,J＝7.5Hz,1H),9.27(d,J＝5.5Hz,1H)。¹³C NMR(125MHz,CDCl₃):δ21.34,21.62,34.37,109.11,110.72,112.44,112.51,114.15,114.26,116.32,116.36,116.84,118.25,119.54,119.82,122.29,123.06,123.57,124.12,129.23,131.80,135.51,135.57,138.76,144.36,150.50,150.68,151.00,152.57,152.99,153.67,196.14。HRMS(ESI):C₃₃H₂₅N₄O¹⁰⁶Pd[M+H]⁺Calculated 599.1058, found 599.1062.

Example 2: the luminescent material PtON5-mi can be synthesized by the following route:

(1) synthesis of intermediate 3-mi: to a dry three-necked flask with a magnetic stirrer was added 1-m (2.12g,7.73mmol,1.0 equivalent), 2-i (2.68g,8.50mmol,1.1 equivalent), cuprous iodide (147mg,0.77mmol,10 mol%), 2-picolinic acid (191mg,1.55mmol,20 mol%) and potassium phosphate (3.28g,15.46mmol,2.0 equivalent) in that order, followed by purging nitrogen three times and adding dimethyl sulfoxide (40mL) under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, extracted by adding ethyl acetate, the organic layer was washed twice with water and the aqueous layer was extracted twice with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/ethyl acetate 10:1-3:1 gave the product 3-mi as a brown solid, 3.58g, 91% yield.¹H NMR(500MHz,CDCl₃):δ1.29(d,J＝7.0Hz,6H),2.46(s,3H),2.92-3.00(m,1H),6.99(t,J＝2.0Hz,1H),7.01(t,J＝1.5Hz,1H),7.08(dd,J＝8.5,2.0Hz,2H),7.12(d,J＝4.5Hz,1H),7.28-7.34(m,3H),7.41-7.44(m,2H),7.54(d,J＝8.5Hz,1H),7.63(d,J＝8.5Hz,1H),7.75(d,J＝8.5Hz,1H),7.84(dd,J＝7.0,2.0Hz,1H),8.08(t,J＝8.5Hz,3H),8.53(d,J＝5.0Hz,1H)。

(2) Synthesis of ligand LON 5-mi: adding 3-phase into a drying sealed pipe with a magnetic stirring rotormi (2.91g,5.72mmol,1.0 eq), then nitrogen was purged three times and toluene (60mL) and methyl iodide (974mg,6.86mmol,1.2 eq) were added under nitrogen. The mixture was stirred in an oil bath at 100 ℃ for 2 days, cooled to room temperature, filtered, the filtrate was rinsed with petroleum ether, dried, the resulting grey solid was added to methanol/water (60mL/6mL), ammonium hexafluorophosphate (1.40g,8.58mmol,1.5 eq.) was added after dissolution with stirring, and the reaction was stirred at room temperature for 3 days. Adding water, evaporating most of methanol under reduced pressure, filtering, washing with water, washing with petroleum ether, and drying to obtain gray solid 2.95g with yield of 77%.¹H NMR(500MHz,CDCl₃):δ1.28(d,J＝7.0Hz,6H),2.48(s,3H),2.95-3.01(m,1H),4.16(s,3H),6.98(t,J＝2.0Hz,1H),7.08(dd,J＝8.5,2.0Hz,1H),7.14(d,J＝5.0Hz,1H),7.16(t,J＝2.0Hz,1H),7.26(d,J＝2.0Hz,1H),7.28-7.31(m,1H),7.39-7.43(m,2H),7.57-7.60(m,2H),7.62-7.65(m,1H),7.68(d,J＝8.0Hz,1H),7.72(dd,J＝8.5,2.0Hz,2H),8.05(d,J＝7.5Hz,1H),8.10(d,J＝8.0Hz,1H),8.51(d,J＝5.0Hz,1H),9.23(s,1H)。¹³C NMR(125MHz,CDCl₃):δ21.10,23.38,33.54,34.12,103.08,110.87,110.93,113.17,113.22,113.27,117.10,118.00,119.58,119.87,120.99,121.38,122.94,123.64,125.81,127.60,127.81,131.01,131.91,133.50,139.94,140.57,140.60,149.20,150.40,151.19,154.12,154.15,159.61。HRMS(ESI):C₃₅H₃₁N₄O[M]⁺Calculated 523.2492, found 523.2494.

(3) Synthesis of PdON 5-mi: to a sealed tube with a magnetic stirrer was added the ligand LON5-mi (200mg,0.30mmol,1.0 equiv.), palladium acetate (74mg,0.33mmol,1.10 equiv.) and potassium carbonate (124mg,0.90mmol,3.0 equiv.) in that order, then nitrogen was purged three times and dioxane (15mL) was added under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/dichloromethane 10:1-3:1 gave the product PdON5-mi as a white solid 100mg, 53% yield.¹H NMR(500MHz,DMSO-d₆):δ1.36(d,J＝7.0Hz,6H),2.46(s,3H),3.07-3.16(m,1H),4.08(s,3H),6.91(d,J＝1.0Hz,1H),7.16-7.19(m,2H),7.37(t,J＝7.5Hz,1H),7.45-7.56(m,4H),7.80(d,J＝8.0Hz,1H),7.90(d,J＝8.0Hz,1H),7.93(s,1H),8.08(d,J＝8.5Hz,1H),8.13(d,J＝7.5Hz,1H),8.39(d,J＝8.0Hz,1H),9.20(d,J＝6.0Hz,1H)。¹³C NMR(125MHz,CDCl₃):δ21.34,24.27,34.23,34.35,106.81,110.74,111.36,112.32,112.44,114.26,116.34,116.82,118.31,119.52,119.80,120.41,122.28,123.04,123.56,124.13,129.20,131.79,135.52,138.75,144.35,147.13,150.46,150.64,151.03,152.55,152.85,153.71,196.06。HRMS(ESI):C₃₅H₂₉N₄O¹⁰⁶Pd[M+H]⁺Calculated 627.1371, found 627.1378.

Example 3: the luminescent material PtON5-mt can be synthesized by the following route:

(1) synthesis of intermediate 3-mt: to a dry three-necked flask with a magnetic stirrer was added 1-m (4.92g,17.94mmol,1.0 equivalent), 2-t (6.50g,19.73mmol,1.1 equivalent), cuprous iodide (341mg,1.79mmol,10 mol%), 2-picolinic acid (442mg,3.59mmol,20 mol%) and potassium phosphate (7.62g,35.88mmol,2.0 equivalent) in that order, followed by purging nitrogen three times and adding dimethyl sulfoxide (80mL) under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, extracted by adding ethyl acetate, the organic layer was washed twice with water and the aqueous layer was extracted twice with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/ethyl acetate 10:1-3:1 gave the product 3-mt as a brown solid, 8.06g, 86% yield.¹H NMR(500MHz,CDCl₃):δ1.36(s,9H),2.47(s,3H),6.96(s,1H),7.09(dd,J＝8.5,2.0Hz,1H),7.13(d,J＝4.5Hz,1H),7.22(t,J＝2.5Hz,2H),7.27-7.33(m,3H),7.42(t,J＝7.5Hz,2H),7.52(d,J＝8.0Hz,1H),7.63(s,1H),7.74(d,J＝8.5Hz,1H),7.83(d,J＝6.5Hz,1H),8.08(t,J＝7.0Hz,3H),8.53(d,J＝5.0Hz,1H)。

(2) Synthesis of ligand LON 5-mt: to a dry sealed tube with magnetic stirring rotor was added 3-mt (4.00g,7.65mmol,1.0 eq.) and then nitrogen was purged three timesToluene (80mL) and methyl iodide (1.30g,9.18mmol,1.2 equiv.) were added under nitrogen. The mixture was stirred in an oil bath at 100 ℃ for 2 days, cooled to room temperature, filtered, the filtrate was rinsed with petroleum ether, dried, the resulting grey solid was added to methanol/water (80mL/8mL), ammonium hexafluorophosphate (1.87g,11.48mmol,1.5 eq.) was added after dissolution with stirring, and the reaction was stirred at room temperature for 3 days. Adding water, evaporating most of methanol under reduced pressure, filtering, washing with water, washing with petroleum ether, and drying to obtain gray solid 3.97g with yield of 76%.¹H NMR(500MHz,CDCl₃):δ1.34(s,9H),2.46(s,3H),4.13(s,3H),6.96(t,J＝2.0Hz,1H),7.08(dd,J＝8.5,2.0Hz,1H),7.12(dd,J＝5.0,0.5Hz,1H),7.27-7.29(m,1H),7.35(t,J＝2.0Hz,1H),7.37-7.40(m,2H),7.42(s,1H),7.54-7.57(m,1H),7.59-7.65(m,3H),7.70(d,J＝8.5Hz,2H),8.03(d,J＝7.5Hz,1H),8.09(d,J＝8.5Hz,1H),8.49(d,J＝5.0Hz,1H),9.18(s,1H)。¹³C NMR(125MHz,CDCl₃):δ21.17,30.90,33.58,35.41,103.04,110.51,110.91,113.19,113.26,113.30,116.47,117.48,119.66,119.93,121.06,121.09,121.45,122.95,123.74,125.83,127.64,127.86,131.20,131.98,133.28,140.02,140.66,140.72,149.27,150.39,151.30,154.25,156.85,159.49。HRMS(ESI):C₃₆H₃₃N₄O[M]⁺Calculated 537.2649, found 537.2658.

(3) Synthesis of PdON 5-mt: to a sealed tube with a magnetic stirrer was added the ligand LON5-mt (198mg,0.29mmol,1.0 equiv.), palladium acetate (72mg,0.32mmol,1.10 equiv.) and potassium carbonate (120mg,0.87mmol,3.0 equiv.) in that order, then nitrogen was purged three times and dioxane (15mL) was added under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/dichloromethane 10:1-3:1 gave the product PdON5-mt as a white solid, 102mg, 55% yield.¹H NMR(500MHz,DMSO-d₆):δ1.46(s,9H),2.45(s,3H),4.08(s,3H),7.03(s,1H),7.17(d,J＝5.0Hz,1H),7.20(d,J＝8.5Hz,1H),7.37(t,J＝7.5Hz,1H),7.45-7.51(m,2H),7.54-7.58(m,1H),7.63(d,J＝1.5Hz,1H),7.81(d,J＝7.5Hz,1H),7.89(d,J＝8.0Hz,1H),7.93(s,1H),8.08(d,J＝8.0Hz,1H),8.13(d,J＝7.5Hz,1H),8.28(d,J＝8.0Hz,1H),9.19(d,J＝6.0Hz,1H)。¹³C NMR(125MHz,CDCl₃):δ21.37,31.65,34.37,34.80,105.66,110.65,110.77,112.26,112.46,114.26,116.35,116.41,116.84,118.29,119.49,119.82,119.99,122.30,123.06,123.57,124.20,129.22,131.82,135.56,138.76,144.36,149.53,150.52,150.60,151.04,152.36,152.82,153.79,196.11。HRMS(ESI):C₃₆H₃₁N₄O¹⁰⁶Pd[M+H]⁺Calculated 641.1527, found 641.1529.

Example 4: the luminescent material PtON5-ti can be synthesized according to the following route:

(1) synthesis of intermediate 3-ti: to a dry three-necked flask with a magnetic stirrer was added 1-t (2.20g,6.95mmol,1.0 equivalent), 2-i (2.41g,7.65mmol,1.1 equivalent), cuprous iodide (133mg,0.70mmol,10 mol%), 2-picolinic acid (171mg,1.39mmol,20 mol%) and potassium phosphate (2.95g,13.90mmol,2.0 equivalent) in that order, followed by purging nitrogen three times and adding dimethyl sulfoxide (50mL) under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, extracted by adding ethyl acetate, the organic layer was washed twice with water and the aqueous layer was extracted twice with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/ethyl acetate 10:1-3:1 gave the product 3-ti as a brown solid 3.61g in 94% yield.¹H NMR(500MHz,CDCl₃):δ1.28(d,J＝7.0Hz,6H),1.35(s,9H),2.92-3.00(m,1H),7.02(s,2H),7.08-7.10(m,2H),7.28-7.34(m,4H),7.43(t,J＝7.0Hz,1H),7.52-7.54(m,1H),7.58(d,J＝1.5Hz,1H),7.64(d,J＝2.5Hz,1H),7.73(d,J＝8.0Hz,1H),7.84(dd,J＝7.0,2.5Hz,1H),8.09(t,J＝7.0Hz,3H),8.58(d,J＝5.5Hz,1H)。HRMS(ESI):C₃₇H₃₅N₄O[M+H]⁺Calculated 551.2805, found 551.2813.

(2) Synthesis of ligand LON 5-ti: to a dry lock tube with magnetic stirring was added 3-ti (3.43g, 6).23mmol,1.0 eq), then nitrogen was purged three times and toluene (68mL) and methyl iodide (1.06g,7.48mmol,1.2 eq) were added under nitrogen. The mixture was stirred in an oil bath at 100 ℃ for 2 days, cooled to room temperature, filtered, the filtrate rinsed with petroleum ether, dried, the resulting grey solid added to methanol/water (68mL/6.8mL), after dissolution with stirring ammonium hexafluorophosphate (1.52g,9.35mmol,1.5 eq.) was added and the reaction was stirred at room temperature for 3 days. Adding water, evaporating most of methanol under reduced pressure, filtering, washing with water, washing with petroleum ether, and drying to obtain gray solid 3.54g with yield of 80%.¹H NMR(500MHz,CDCl₃):δ1.28(d,J＝7.0Hz,6H),1.38(s,9H),2.96-3.02(m,1H),4.20(s,3H),7.00(t,J＝2.0Hz,1H),7.09(dd,J＝8.5,2.0Hz,1H),7.18(s,1H),7.28-7.32(m,3H),7.42(t,J＝7.5Hz,1H),7.58-7.74(m,7H),8.07(d,J＝7.5Hz,1H),8.11(d,J＝8.5Hz,1H),8.56(d,J＝5.5Hz,1H),9.27(s,1H)。¹³C NMR(125MHz,CDCl₃):δ23.40,30.48,33.62,34.19,35.10,103.04,110.66,111.02,113.23,113.30,113.31,116.21,117.26,118.30,119.07,120.02,120.99,121.08,121.43,123.79,125.87,127.65,127.88,131.12,132.00,133.48,140.02,140.71,149.47,151.37,154.33,154.40,159.60,163.37。HRMS(ESI):C₃₈H₃₇N₄O[M]⁺Calculated 565.2962, found 565.2969.

(3) Synthesis of PdON 5-ti: to a stopcock with a magnetic stirrer was added the ligand LON5-ti (199mg,0.28mmol,1.0 equiv.), palladium acetate (70mg,0.31mmol,1.10 equiv.) and potassium carbonate (116mg,0.84mmol,3.0 equiv.) in that order, then the nitrogen was purged three times and dioxane (15mL) was added under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/dichloromethane 10:1-3:1 gave the product PdON5-ti as a white solid 103mg, 55% yield.¹H NMR(500MHz,DMSO-d₆):δ1.32(s,9H),1.36(d,J＝7.0Hz,6H),3.08-3.14(m,1H),4.08(s,3H),6.91(d,J＝1.0Hz,1H),7.19(d,J＝8.5Hz,1H),7.33-7.38(m,2H),7.46-7.55(m,4H),7.79(dd,J＝8.0,1.0Hz,1H),7.90(d,J＝8.0Hz,1H),8.00(d,J＝1.5Hz,1H),8.06(d,J＝8.0Hz,1H),8.14(d,J＝7.5Hz,1H),8.37(d,J＝8.5Hz,1H),9.22(d,J＝6.0Hz,1H)。¹³C NMR(125MHz,CDCl₃):δ24.28,30.16,34.23,34.45,35.38,106.83,110.74,111.34,112.41,112.45,113.27,113.89,115.97,116.33,116.91,118.18,119.93,120.41,122.20,123.04,123.63,124.14,129.20,131.85,135.57,138.90,144.46,147.09,150.56,150.60,152.63,153.22,153.84,163.81,196.13。HRMS(ESI):C₃₈H₃₅N₄O¹⁰⁶Pd[M+H]⁺Calculated 669.1840, found 669.1837.

Example 5: the luminescent material PtON5-tt can be synthesized as follows:

(1) synthesis of intermediate 3-tt: to a dry three-necked flask with a magnetic stirrer were added 1-t (2.50g,7.90mmol,1.0 equivalent), 2-t (2.86g,8.69mmol,1.1 equivalent), cuprous iodide (150mg,0.79mmol,10 mol%), 2-picolinic acid (195mg,1.58mmol,20 mol%) and potassium phosphate (3.35g,15.80mmol,2.0 equivalent) in that order, followed by purging nitrogen three times and adding dimethyl sulfoxide (50mL) under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, extracted by adding ethyl acetate, the organic layer was washed twice with water and the aqueous layer was extracted twice with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/ethyl acetate 10:1-2:1 gave the product 3-tt as a brown solid in 3.90g, 87% yield.¹H NMR(500MHz,CDCl₃):δ1.35(s,18H),6.99(t,J＝2.0Hz,1H),7.09(dd,J＝8.5,2.0Hz,1H),7.22(s,2H),7.28-7.34(m,4H),7.43(t,J＝7.5Hz,1H),7.52(d,J＝7.5Hz,1H),7.58(d,J＝1.0Hz,1H),7.61(d,J＝2.0Hz,1H),7.73(d,J＝8.5Hz,1H),7.84(d,J＝7.5Hz,1H),8.09(t,J＝7.0Hz,3H),8.75(d,J＝5.5Hz,1H)。HRMS(ESI):C₃₈H₃₇N₄O[M+H]⁺Calculated 565.2963, found 565.2962.

(2) Synthesis of ligand LON 5-tt: 3-tt (3.90g,6.91mmol,1.0 equiv.) was added to a dry lock tube with magnetically stirred rotor,the nitrogen was then purged three times and toluene (78mL) and methyl iodide (1.18g,8.29mmol,1.2 equiv.) were added under nitrogen. The mixture was stirred in an oil bath at 100 ℃ for 2 days, cooled to room temperature, filtered, the filtrate rinsed with petroleum ether, dried, the resulting grey solid added to methanol/water (78mL/7.8mL), after dissolution with stirring ammonium hexafluorophosphate (1.69g,10.37mmol,1.5 eq.) was added and the reaction was stirred at room temperature for 3 days. Adding water, evaporating most of methanol under reduced pressure, filtering, washing with water, washing with petroleum ether, and drying to obtain gray solid 4.01g with yield of 80%.¹H NMR(500MHz,CDCl₃):δ1.36(s,9H),1.38(s,9H),4.20(s,3H),6.97(t,J＝2.5Hz,1H),7.10(dd,J＝8.5,2.0Hz,1H),7.30-7.32(m,2H),7.38(t,J＝2.0Hz,1H),7.40-7.44(m,2H),7.58-7.74(m,7H),8.07(d,J＝7.5Hz,1H),8.11(d,J＝8.5Hz,1H),8.56(d,J＝5.5Hz,1H),9.27(s,1H)。¹³C NMR(125MHz,CDCl₃):δ30.55,30.95,33.73,35.16,35.51,103.04,110.69,110.76,113.18,113.27,113.52,116.27,116.67,117.84,119.07,120.06,121.11,121.14,121.47,123.93,125.92,127.73,127.98,131.40,132.12,133.28,140.19,140.88,140.98,149.55,151.56,154.56,157.18,159.54,163.42。HRMS(ESI):C₃₉H₃₉N₄O[M]⁺Calculated 579.3118, found 579.3134.

(3) Synthesis of PdON 5-tt: to a sealed tube with a magnetic stirrer was added the ligands LON5-tt (200mg,0.28mmol,1.0 equiv.), palladium acetate (70mg,0.31mmol,1.10 equiv.) and potassium carbonate (116mg,0.84mmol,3.0 equiv.) in that order, then nitrogen was purged three times and dioxane (15mL) was added under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/dichloromethane 10:1-3:1 gave the product PdON5-tt as a white solid, 68mg, 36% yield.¹H NMR(500MHz,DMSO-d₆):δ1.33(s,9H),1.47(s,9H),4.09(s,3H),7.03(d,J＝1.0Hz,1H),7.20(d,J＝8.0Hz,1H),7.35-7.39(m,2H),7.46-7.52(m,2H),7.56(t,J＝7.5Hz,1H),7.62(s,1H),7.81(d,J＝8.0Hz,1H),7.90(d,J＝8.5Hz,1H),8.01(s,1H),8.06(d,J＝8.5Hz,1H),8.14(d,J＝7.5Hz,1H),8.27(d,J＝8.0Hz,1H),9.23(d,J＝6.0Hz,1H)。¹³C NMR(125MHz,CDCl₃):δ30.17,31.67,34.45,34.81,35.39,105.63,110.67,110.77,112.26,112.45,113.31,113.88,115.97,116.32,116.90,118.18,119.93,120.08,122.19,123.02,123.63,124.20,129.19,131.83,135.55,138.90,144.47,149.46,150.55,150.57,152.46,153.16,153.91,163.83,196.11。HRMS(ESI):C₃₉H₃₇N₄O¹⁰⁶Pd[M+H]⁺Calculated 683.1997, found 683.1996.

Example 6: the luminescent material PtON7p-mt can be synthesized according to the following route:

(1) synthesis of intermediate 3 p-mt: to a dry three-necked flask with a magnetic stirrer were added 1-m (1.55g,5.65mmol,1.0 equivalent), 2p-t (2.21g,6.22mmol,1.1 equivalent), cuprous iodide (109mg,0.57mmol,10 mol%), 2-picolinic acid (139mg,1.13mmol,20 mol%) and potassium phosphate (2.40g,11.30mmol,2.0 equivalent) in that order, followed by purging nitrogen three times and adding dimethyl sulfoxide (31mL) under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, extracted by adding ethyl acetate, the organic layer was washed twice with water and the aqueous layer was extracted twice with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/ethyl acetate 10:1-3:1 gave the product 3p-mt as a brown solid, 2.60g, 84% yield.¹H NMR(500MHz,CDCl₃):δ1.34(s,9H),2.47(s,3H),6.88(t,J＝2.0Hz,1H),7.05(dd,J＝8.0,2.0Hz,1H),7.12-7.14(m,3H),7.24(d,J＝7.5Hz,1H),7.32(t,J＝7.5Hz,1H),7.37(t,J＝7.5Hz,2H),7.40-7.44(m,2H),7.48(d,J＝1.0Hz,1H),7.60(d,J＝2.0Hz,1H),7.75(d,J＝8.5Hz,1H),7.80(d,J＝7.5Hz,2H),7.83(d,J＝0.5Hz,1H),8.08(dd,J＝7.5,4.0Hz,2H),9.53(d,J＝5.5Hz,1H)。

(2) Synthesis of ligand LON7 p-mt: to a dry lock with magnetic stirrer was added 3p-mt (2.60g,4.74mmol,1.0 eq), then the nitrogen was purged three times and toluene (52mL) and methyl iodide (807mg, 5) were added under nitrogen blanket.69mmol,1.2 equiv). The mixture was stirred in an oil bath at 100 ℃ for 2 days, cooled to room temperature, filtered, the filtrate rinsed with petroleum ether, dried, the resulting grey solid added to methanol/water (52mL/5.2mL), after dissolution with stirring ammonium hexafluorophosphate (1.16g,7.11mmol,1.5 eq.) was added and the reaction was stirred at room temperature for 3 days. Adding water, evaporating most of methanol under reduced pressure, filtering, washing with water, washing with petroleum ether, and drying to obtain gray solid 1.95g with yield of 58%.¹H NMR(500MHz,DMSO-d₆):δ1.34(s,9H),2.45(s,3H),3.88(s,3H),7.11(dd,J＝8.5,2.0Hz,1H),7.30-7.36(m,4H),7.44-7.48(m,1H),7.54(d,J＝2.0Hz,1H),7.59-7.61(m,5H),7.66-7.69(m,2H),7.77(d,J＝8.0Hz,1H),8.24(d,J＝7.5Hz,1H),8.30(d,J＝8.0Hz,1H),8.52(d,J＝5.0Hz,1H),8.54(d,J＝1.5Hz,1H),9.84(d,J＝1.5Hz,1H)。¹³C NMR(125MHz,CDCl₃):δ21.11,30.83,34.73,35.33,103.07,108.39,110.94,113.29,114.14,116.97,118.24,119.65,119.88,121.01,121.08,121.40,122.94,123.70,124.10,125.83,129.24,129.50,130.73,135.19,135.25,136.59,140.02,140.62,149.20,150.40,151.21,154.17,156.50,159.46。HRMS(ESI):C₃₈H₃₅N₄O[M]⁺Calculated 563.2805, found 563.2798.

(3) Synthesis of Pdon7 p-mt: to a stopcock with a magnetic stirrer was added the ligand LON7p-mt (198mg,0.28mmol,1.0 equiv.), palladium acetate (70mg,0.31mmol,1.10 equiv.) and potassium carbonate (116mg,0.84mmol,3.0 equiv.) in that order, then nitrogen was purged three times and dioxane (15mL) was added under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/dichloromethane 10:1-3:1 gave the product PdON7p-mt as a white solid 99mg, 53% yield.¹H NMR(500MHz,DMSO-d₆):δ1.38(s,9H),2.44(s,3H),3.88(s,3H),6.93(d,J＝1.5Hz,1H),7.17(d,J＝8.5Hz,1H),7.35(t,J＝7.0Hz,1H),7.41(d,J＝1.5Hz,1H),7.42-7.45(m,2H),7.48-7.52(m,1H),7.57(t,J＝7.5Hz,2H),7.73-7.74(m,2H),7.87(d,J＝8.5Hz,1H),7.90(s,1H),8.05(d,J＝8.5Hz,1H),8.11(d,J＝7.5Hz,1H),8.47(s,1H),9.24(d,J＝6.5Hz,1H)。¹³C NMR(125MHz,CDCl₃):δ21.34,31.52,34.67,36.03,103.39,110.86,112.58,113.31,114.28,116.34,116.55,117.91,119.23,119.64,119.77,122.21,123.49,128.47,128.89,128.93,129.03,129.25,134.25,138.79,144.47,148.89,149.37,150.48,150.80,152.73,152.89,153.95,187.41。HRMS(ESI):C₃₈H₃₃N₄O¹⁰⁶Pd[M+H]⁺Calculated 667.1684, found 667.1703.

Example 7: the luminescent material PtON7p-tt can be synthesized as follows:

(1) synthesis of intermediate 3 p-tt: to a dry three-necked flask with a magnetic stirrer were added 1-t (1.50g,4.74mmol,1.0 equivalent), 2p-t (1.85g,5.21mmol,1.1 equivalent), cuprous iodide (90mg,0.47mmol,10 mol%), 2-picolinic acid (117mg,0.95mmol,20 mol%) and potassium phosphate (2.01g,9.48mmol,2.0 equivalent) in that order, then nitrogen was purged three times and dimethyl sulfoxide (30mL) was added under nitrogen protection. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, extracted by adding ethyl acetate, the organic layer was washed twice with water and the aqueous layer was extracted twice with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/ethyl acetate 10:1-3:1 gave the product 3p-tt as a brown solid, 2.50g, 89% yield.¹H NMR(500MHz,CDCl₃):δ1.34(s,9H),1.35(s,9H),6.91(t,J＝2.0Hz,1H),7.06(dd,J＝7.0,2.0Hz,1H),7.14(t,J＝2.0Hz,2H),7.24(d,J＝7.5Hz,1H),7.28(dd,J＝5.5,1.5Hz,1H),7.33(t,J＝7.5Hz,1H),7.37(t,J＝7.5Hz,2H),7.41-7.45(m,1H),7.48(d,J＝1.0Hz,1H),7.56(d,J＝2.5Hz,1H),7.57(d,J＝1.0Hz,1H),7.73(d,J＝8.0Hz,1H),7.80-7.81(m,2H),7.84(d,J＝1.0Hz,1H),8.09(dd,J＝8.5,2.5Hz,2H),8.57(d,J＝5.0Hz,1H)。HRMS(ESI):C₄₀H₃₉N₄O[M+H]⁺Calculated 591.3118, found 591.3133.

(2) Synthesis of ligand LON7 p-tt: adding into a drying sealed tube with a magnetic stirring rotor3p-tt (2.42g,4.10mmol,1.0 eq), then nitrogen was purged three times and toluene (48mL) and methyl iodide (698mg,4.92mmol,1.2 eq) were added under nitrogen. The mixture was stirred in an oil bath at 100 ℃ for 2 days, cooled to room temperature, filtered, the filtrate was rinsed with petroleum ether, dried, the resulting grey solid was added to methanol/water (48mL/4.8mL), after dissolution with stirring ammonium hexafluorophosphate (1.00g,6.15mmol,1.5 equivalents) was added and the reaction was stirred at room temperature for 3 days. Adding water, evaporating most of methanol under reduced pressure, filtering, washing with water, washing with petroleum ether, and drying to obtain gray solid 2.00g with yield of 65%.¹H NMR(500MHz,CDCl₃):δ1.32(s,9H),1.37(s,9H),3.86(s,3H),6.86(t,J＝2.0Hz,1H),7.04(dd,J＝8.0,2.0Hz,1H),7.28-7.33(m,4H),7.39-7.45(m,4H),7.47-7.52(m,3H),7.57(dd,J＝8.5,2.0Hz,2H),7.69(d,J＝8.0Hz,1H),8.08(d,J＝7.5Hz,1H),8.10(d,J＝8.5Hz,1H),8.55(d,J＝5.5Hz,1H),9.00(d,J＝1.5Hz,1H)。¹³C NMR(125MHz,CDCl₃):δ30.38,30.78,34.70,35.02,35.29,102.93,108.62,110.64,113.18,114.20,116.18,117.05,118.26,119.05,119.94,120.84,121.04,121.37,123.72,124.10,125.82,129.21,129.48,130.68,135.19,136.57,139.97,140.65,149.37,151.23,154.37,156.45,159.31,163.34。HRMS(ESI):C₄₁H₄₁N₄O[M]⁺Calculated 605.3275, found 605.3281.

(3) Synthesis of PdON7 p-tt: to a stopcock with a magnetic stirrer was added the ligand LON7p-tt (200mg,0.27mmol,1.0 equiv.), palladium acetate (67mg,0.30mmol,1.10 equiv.) and potassium carbonate (112mg,0.81mmol,3.0 equiv.) in that order, then nitrogen was purged three times and dioxane (15mL) was added under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/dichloromethane 10:1-3:1 gave the product PdON7p-tt as a white solid 98mg with a yield of 52%.¹H NMR(500MHz,DMSO-d₆):δ1.34(s,9H),1.38(s,9H),3.90(s,3H),6.93(d,J＝1.5Hz,1H),7.17(d,J＝8.0Hz,1H),7.35-7.38(m,2H),7.40(d,J＝1.5Hz,1H),7.44-7.47(m,1H),7.51(t,J＝7.5Hz,1H),7.58(t,J＝8.0Hz,2H),7.74(d,J＝7.0Hz,2H),7.88(d,J＝8.0Hz,1H),8.00(d,J＝2.0Hz,1H),8.05(d,J＝8.0Hz,1H),8.14(d,J＝7.5Hz,1H),8.48(s,1H),9.29(d,J＝6.5Hz,1H)。¹³C NMR(125MHz,CDCl₃):δ30.24,31.52,34.67,35.41,36.17,103.37,110.86,112.57,113.31,113.33,113.91,115.49,116.29,116.60,117.79,119.67,119.89,122.13,123.56,128.52,128.90,128.94,129.04,129.22,134.26,138.91,144.54,148.90,149.35,150.55,152.92,154.05,163.63,187.52。HRMS(ESI):C₄₁H₃₉N₄O¹⁰⁶Pd[M+H]⁺Calculated 709.2153, found 709.2159.

Example 8: the luminescent material PtON5N-tt can be synthesized as follows:

(1) synthesis of intermediate 3N-tt: to a dry three-necked flask with a magnetic stirrer were added 1-t (2.49g,7.87mmol,1.0 equivalent), 2N-t (2.60g,7.87mmol,1.1 equivalent), cuprous iodide (150mg,0.79mmol,10 mol%), 2-picolinic acid (193mg,1.57mmol,20 mol%) and potassium phosphate (3.34g,15.74mmol,2.0 equivalent) in that order, then nitrogen was purged three times and dimethyl sulfoxide (60mL) was added under nitrogen protection. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, extracted by adding ethyl acetate, the organic layer was washed twice with water and the aqueous layer was extracted twice with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and the solvent was distilled off under reduced pressure. Separating and purifying the obtained crude product by using a silica gel chromatographic column, eluting a eluent: petroleum ether/ethyl acetate 10:1-3:1 gave the product 3N-tt as a brown solid, 3.82g, 86% yield.¹H NMR(500MHz,CDCl₃):δ1.34(s,9H),1.35(s,9H),7.09(dd,J＝8.5,2.0Hz,1H),7.21(t,J＝2.0Hz,1H),7.24(t,J＝2.0Hz,1H),7.27-7.33(m,3H),7.43(td,J＝8.5,1.5Hz,1H),7.46(t,J＝1.5Hz,1H),7.58(d,J＝2.5Hz,2H),7.73(d,J＝8.0Hz,1H),8.08(dd,J＝7.5,2.0Hz,2H),8.12(d,J＝7.5Hz,1H),8.29(s,1H),8.40(dd,J＝5.5,1.5Hz,1H),8.57(d,J＝5.0Hz,1H)。¹³C NMR(125MHz,CDCl₃):δ30.45,31.13,35.01,35.15,102.41,110.84,110.88,113.02,115.20,115.29,116.16,118.76,119.80,120.51,120.95,121.08,123.93,125.63,128.14,135.80,140.06,140.71,143.01,144.92,146.79,149.41,151.53,154.84,155.30,158.71,163.08。HRMS(ESI):C₃₇H₃₆N₅O[M+H]⁺Calculated 566.2914, found 566.2935.

(2) Synthesis of ligand LON 5N-tt: to a dry lock with magnetic stirring was added 3N-tt (1.40g,2.47mmol,1.0 eq), then nitrogen was purged three times and toluene (42mL) and methyl iodide (420mg,2.96mmol,1.2 eq) were added under nitrogen. The mixture was stirred in an oil bath at 100 ℃ for 2 days, cooled to room temperature, filtered, the filtrate rinsed with petroleum ether, dried, the resulting grey solid added to methanol/water (28mL/2.8mL), after dissolution with stirring ammonium hexafluorophosphate (605mg,3.71mmol,1.5 eq.) was added and the reaction stirred at room temperature for 3 days. Adding water, evaporating most of methanol under reduced pressure, filtering, washing with water, washing with petroleum ether, and drying to obtain gray solid 1.33g with yield of 74%.¹H NMR(500MHz,CDCl₃):δ1.35(s,9H),1.36(s,9H),4.20(s,3H),7.10(dd,J＝8.5,2.0Hz,1H),7.21(t,J＝2.0Hz,1H),7.28-7.30(m,2H),7.36-7.41(m,2H),7.51(t,J＝1.5Hz,1H),7.57(dd,J＝6.0,1.5Hz,2H),7.63(dd,J＝8.0,4.5Hz,1H),7.67(d,J＝8.0Hz,1H),8.05(d,J＝8.0Hz,1H),8.09(d,J＝8.5Hz,1H),8.13(dd,J＝8.5,1.5Hz,1H),8.56(d,J＝5.5Hz,1H),8.69(dd,J＝5.5,1.5Hz,1H),9.46(s,1H)。¹³C NMR(125MHz,DMSO-d₆):δ30.05,30.79,33.93,34.89,35.12,101.73,111.17,112.17,113.07,115.88,117.02,117.22,119.35,120.06,120.22,121.26,121.96,122.53,123.20,123.65,125.23,126.12,133.32,139.50,140.03,142.76,144.24,148.64,149.46,150.66,154.90,155.01,157.77,163.19。HRMS(ESI):C₃₈H₃₈N₅O[M]⁺Calculated 580.3071, found 580.3076.

(3) Synthesis of PdON 5N-tt: to a sealed tube with a magnetic stirrer was added the ligand LON5N-tt (726mg,1.00mmol,1.0 equiv.), palladium acetate (247mg,1.10mmol, 1.10 equiv.), and potassium carbonate (276mg,2.00mmol,3.0 equiv.) in that order, then nitrogen was purged three times and dioxane (50mL) was added under nitrogen. The mixture was stirred in an oil bath at 110 ℃ for 2 days, cooled to room temperature, and the solvent was distilled off under reduced pressure. The crude product is chromatographed on silica gelColumn separation and purification, eluent: petroleum ether/dichloromethane ═ 10:1-3:1 to give the product PdON5N-tt as a white solid 454mg, 66% yield.¹H NMR(500MHz,DMSO-d₆):δ1.33(s,9H),1.43(s,9H),4.11(s,3H),7.04(d,J＝2.0Hz,1H),7.21(d,J＝8.0Hz,1H),7.34(dd,J＝6.0,1.5Hz,1H),7.38(d,J＝7.5Hz,1H),7.47-7.50(m,1H),7.53(dd,J＝8.0,4.5Hz,1H),7.91(d,J＝8.5Hz,1H),8.01(d,J＝1.5Hz,1H),8.06(d,J＝8.0Hz,1H),8.15(d,J＝7.5Hz,1H),8.26(dd,J＝8.5,1.5Hz,1H),8.62(dd,J＝5.0,1.0Hz,2H),9.24(d,J＝6.5Hz,1H)。¹³C NMR(125MHz,CDCl₃):δ30.01,31.71,34.40,34.90,35.24,108.23,110.64,112.59,112.95,113.96,116.23,116.32,116.87,117.95,118.06,118.34,119.66,119.87,122.18,123.66,127.48,129.09,138.89,144.40,144.50,145.20,149.32,150.22,152.25,153.24,154.01,163.76,197.17。HRMS(ESI):C₃₈H₃₆N₅O¹⁰⁶Pd[M+H]⁺Calculated 684.1949, found 684.1943.

Evaluation of Performance

The complexes prepared in the above examples of the invention were subjected to photophysical and thermogravimetric analysis as follows:

and (3) photophysical analysis: the steady state emission spectra were tested on a HORIBA FL3-11 spectrometer, and the emission spectra of the luminescent materials synthesized in examples 1-8 are shown in FIGS. 1-8. Test conditions of the emission spectrum: in the room temperature emission spectrum, all samples were dichloromethane (chromatographic grade) dilute solutions (10)^-5-10^-6M), or a 5 wt% doped PMMA (polymethyl methacrylate) film, and the samples were all formulated in a glove box; the excited state lifetime measurements were all measured at the strongest peak of the sample emission spectrum.

TABLE 1 photophysical Properties of luminescent materials in dichloromethane solution at room temperature

Luminescent material	Peak/nm	FWHM/nm	τ/μs
				PtON5-mm	437	48	3.9
PdON5-mi	438	40	3.6
				PdON5-mt	438	44	3.8
PdON5-ti	438	40	2.9
				PdON5-tt	438	40	3.8
PdON7p-mt	439	45	32
				PdON7p-tt	438	44	40
PdON5N-tt	439	41	1.1

Note: peak refers to the emission Peak of the emission spectrum of the luminescent material in methylene chloride solution at room temperature. FWHM refers to the full width at half maximum of the emission spectrum. τ refers to the excited state lifetime of the luminescent material solution sample after oxygen removal.

TABLE 2 photophysical properties of the luminescent materials in PMMA films

Note: PMMA refers to polymethyl methacrylate. Peak refers to the emission Peak of the emission spectrum of the luminescent material in the polymethyl methacrylate film at room temperature. FWHM refers to the full width at half maximum of the emission spectrum. τ refers to the excited state lifetime of the luminescent material solution sample after oxygen removal.

FIGS. 1 to 8 show emission spectra of eight luminescent materials in tables 1 to 2 in 2-methyltetrahydrofuran at 77K, dichloromethane solution at room temperature, and polymethyl methacrylate film at room temperature. The data show that the maximum emission peaks of the four-tooth ring metal carbene palladium complex in a dichloromethane solution and a PMMA film at room temperature are 437-439nm, the half-peak width is small, 34-48nm, the chromaticity coordinate y values of the luminescent colors of the four-tooth ring metal carbene palladium complex are smaller than 0.10, and the four-tooth ring metal carbene palladium complex is a deep blue luminescent material.

FIG. 9 is a thermogravimetric plot of the synthesized luminescent material PtON5N-tt from example 8 having a 5 wt% mass loss temperature of 416 deg.C, indicating that PtON5N-tt has very high thermal stability, much higher than the sublimation evaporation temperature of the material during fabrication of an OLED device (typically no higher than 300 deg.C).

FIG. 10 shows the structure of a single crystal and a molecular stacking diagram of the luminescent material PtON5-mi synthesized in example 2, which demonstrates the structure of the material molecule.

FIG. 11 is a LUMO +1, LUMO, HOMO-1, and triplet spin profiles, and the orbital levels of LUMO +1, LUMO, HOMO, and HOMO-1, for the light-emitting materials PtON5-mm, PtON5-mi, PtON5-mt, PtON5-tt, PtON7p-tt, and PtON 5N-tt; wherein Spin sensitivity (T)₁) Representing the lowest triplet spin. The data show that the front line orbital energy level of the material molecule can be efficiently regulated and controlled through the structural regulation of the carbazole part and the substituent.

FIG. 12 is an electrochemical spectrum of the luminescent materials PtON5-tt, PtON7p-tt and PtON5N-tt in N, N-dimethylformamide at room temperature; wherein ferrocene (Fc) is used as an internal standard, the abscissa is Potential (Potential), and the ordinate is current intensity. The electrochemical data show that the front-line orbital energy level of the material molecule can be efficiently regulated and controlled through the structural regulation of the carbazole part.

FIG. 13 is an absorption spectrum of the luminescent materials PtON5-tt, PtON7p-tt and PtON5N-tt in dichloromethane at room temperature, with absorption around 350nm being metal-to-ligand charge transfer (MLCT) absorption, indicating that metal ions participate in the charge transfer of the excited state of the material molecules.

The invention relates to application of a four-toothed-ring metal carbene palladium complex deep blue light luminescent material as a luminescent layer of an organic electroluminescent device. In an organic light-emitting element, carriers are injected into a light-emitting material from both positive and negative electrodes, and the light-emitting material in an excited state is generated and emits light. The four-toothed-ring metal carbene-palladium complex deep blue light luminescent material is applied to excellent organic luminescent elements such as organic photoluminescence elements or organic electroluminescence elements. The organic photoluminescent element has a structure in which at least a light-emitting layer is formed over a substrate. The organic electroluminescent element has a structure in which at least an anode, a cathode, and an organic layer between the anode and the cathode are formed. The organic layer may be composed of only the light-emitting layer, or may have 1 or more organic layers other than the light-emitting layer. Examples of such other organic layers include a hole transport layer, a hole injection layer, an electron blocking layer, a hole blocking layer, an electron injection layer, an electron transport layer, and an exciton blocking layer. The hole transport layer may be a hole injection transport layer having a hole injection function, and the electron transport layer may be an electron injection transport layer having an electron injection function. Fig. 14 shows a schematic structure of a specific organic light-emitting element. In fig. 14, 7 layers are shown from bottom to top, and a substrate, an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode are sequentially shown, where the light-emitting layer is a mixed layer in which a guest material is doped with a host material.

The compounds represented in examples 1 to 8 were applied as light-emitting materials to OLED devices, and the structures are represented as:

ITO/HATCN (10nm)/NPB (30nm)/TCTA (30nm)/mCBP (10nm)/A3 Metal carbene Palladium Complex (2-30 wt.%, 30nm)/PPT (5 nm)/Li) expressed in examples 1-8 (2-30 wt.%, 30nm)/PPT (5 nm)/Li)₂CO₃:Bepp₂(5％,35nm)/Li₂CO₃(1nm)/Al(100nm)。

Wherein, the ITO is a transparent anode; HATCN is a hole injection layer, NPB and TCTA are hole transport layers, mCBP is an electron blocking layer, A3 is a host material, the metal carbene palladium complex (2-30 wt.% is doping concentration, 30nm is thickness of light emitting layer) represented in examples 1-8 is a guest material, PPT is a hole blocking layer, Li is a hole transporting layer₂CO₃:Bepp₂As electron transport layer, Li₂CO₃Is an electron injection layer and Al is a cathode. The number in parentheses in nanometers (nm) is the thickness of the film.

FIG. 15 is an electroluminescence spectrum of an OLED device fabricated with 7 wt% PtON5N-tt as a doped light emitting material and is deep blue emitting, indicating that it can be used as a doped light emitting material (guest material) for a deep blue OLED device.

It should be noted that the structure is an example of an application of the light emitting material of the present invention, and does not constitute a limitation to the structure of the specific OLED device of the light emitting material of the present invention. For example, NPB or TCTA alone may be used as the hole transport layer.

The molecular formula of the applied material in the device is as follows:

it will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice. For example, many of the substituent structures described herein may be substituted with other structures without departing from the spirit of the invention.

Claims

1. A four-ring metal carbene-palladium deep blue light phosphorescent material is characterized in that the structure of the deep blue light phosphorescent material is any one of (I) to (VIII):

2. The use of the tetradentate ring metal carbene palladium deep blue phosphorescent material as claimed in claim 1 in a light-emitting layer of an organic electroluminescent device.

3. An optical device comprising one or more of the four-ring metal carbene-palladium deep blue phosphorescent materials.