CN115057887A - Dicarbazole phenyl bisphosphine ligand and preparation method thereof, carbazole phenyl bisphosphine cuprous halide and preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of copper complexes, and particularly relates to a 4, 5-dicarbazolylphosphine ligand and a preparation method thereof, as well as carbazole phenylphosphine cuprous halide and a preparation method and application thereof. The bidentate organic phosphine ligand (dcdp) of 1, 2-dicarbazolyl-4, 5-di (diphenylphosphino) benzene provided by the invention reacts with cuprous halide to obtain three binuclear four-coordinate cuprous halide complexes, [ Cu ₂ X ₂ (dcdp) ₂ ][ dcdp ═ 1, 2-dicarbazolyl-4, 5-bis (diphenylphosphino) benzene, X ═ I (1), Br (2), Cl (3)]. The structural analysis shows that 2 halogen atoms and 2 copper atoms are bridged to form the binuclear four-coordinate cuprous halide complex. The complex provided by the invention respectively emits green yellow light, yellow light and yellow orange light in a solid state at room temperature.

Description

Dicarbazole phenyl bisphosphine ligand and preparation method thereof, carbazole phenyl bisphosphine cuprous halide Preparation method and application thereof

technical field

The invention belongs to the technical field of copper complexes, and in particular relates to a 4,5-dicarbazole phenyl bisphosphine ligand and a preparation method thereof, a carbazole phenyl bisphosphine cuprous halide, a preparation method and application thereof.

Background technique

Compared with noble metal iridium and platinum complexes, cuprous complexes have low cost, environmental friendliness, good luminescence properties, and have the potential to replace noble metal phosphorescent complexes. In particular, the low-level MLCT excited states in cuprous complexes have small singlet and triplet energy gaps, which can effectively trap triplet excitons for thermally activated delayed fluorescence (TADF) applications in high-efficiency organic light-emitting diodes (OLEDs).

In recent years, cuprous halide complexes containing organic bisphosphine can reduce the energy loss caused by Jahn-Teller deformation of excited state configuration due to the rigidity of their structure, and can obtain cuprous complexes with high quantum efficiency. Carbazole is a high-efficiency blue light material with rigid structure and large energy level difference, and has good hole transport ability. It is necessary to further explore and develop this technical solution.

SUMMARY OF THE INVENTION

In order to solve the deficiencies of the prior art, the present invention provides a 4,5-dicarbazole phenyl bisphosphine ligand and a preparation method thereof, a carbazole phenyl bisphosphine cuprous halide, a preparation method and application thereof. The carbazole phenyl bisphosphine cuprous halide provided by the invention has a luminescence lifetime of less than 3 microseconds and is highly efficient.

The technical scheme provided by the present invention is as follows:

A 4,5-dicarbazole phenyl bisphosphine ligand, the structural formula is as follows:

The bidentate organophosphine ligand (dcdp) of 1,2-dicarbazolyl-4,5-bis(diphenylphosphino)benzene provided by the present invention can react with cuprous halide to obtain three binuclear Tetracoordinated cuprous halide complexes.

The present invention also provides the preparation method of the above-mentioned 4,5-dicarbazole phenyl bisphosphine ligand, and its synthetic route is as follows:

The present invention also provides a kind of carbazole phenyl bisphosphine cuprous halide, the structural formula is as follows:

The bidentate organophosphine ligand (dcdp) of 1,2-dicarbazolyl-4,5-bis(diphenylphosphino)benzene provided by the present invention reacts with cuprous halide to obtain three binuclear tetra Coordinated cuprous halide complex, [Cu ₂ X ₂ (dcdp) ₂ ][dcdp=1,2-dicarbazolyl-4,5-bis(diphenylphosphino)benzene, X=I(1) , Br(2), Cl(3)]. Structural analysis shows that two halogen atoms are bridged with two copper atoms to form a binuclear tetracoordinate cuprous halide complex.

The present invention also provides the preparation method of above-mentioned carbazole phenyl bisphosphine cuprous halide, and its synthetic route is as follows:

The overall synthetic route is as follows:

The present invention also provides the application of the above-mentioned carbazole phenyl bisphosphine cuprous halide as a fluorescent material.

Further, as a thermally activated delayed fluorescent material.

Specifically, X is I, and the carbazole phenyl bisphosphine cuprous halide is used as a green-yellow fluorescent material.

Specifically, X is Br, and the carbazole phenyl bisphosphine cuprous halide is used as a yellow fluorescent material.

Specifically, X is Cl, and the carbazole phenyl bisphosphine cuprous halide is used as a yellow-orange fluorescent material.

The above-mentioned complexes 1, 2 and 3 provided by the present invention emit green-yellow light, yellow light and yellow-orange light respectively in solid state at room temperature, and the maximum emission wavelengths are 567, 580 and 602 nm respectively. At room temperature, the solid-state absolute internal quantum efficiency Φ _PL is 0.09-0.53, and the luminescence lifetime is 1.2-2.3 μs. The luminescence of complexes 1-3 is thermally activated delayed fluorescence mainly from XLCT (halogen-to-ligand charge transition), MLCT (metal-to-ligand charge transition) and ILCT intra-ligand charge transition (intra-ligand charge transition).

Description of drawings

Figure 1 is the ¹ H NMR spectrum of the ligand dcdp provided by the present invention in CDCl ₃ .

Figure 2 is the ¹ H NMR spectrum of the complex 1 provided by the present invention in CDCl ₃ .

Figure 3 is the ¹ H NMR spectrum of the complex 2 provided by the present invention in CDCl ₃ .

Figure 4 is the ¹ H NMR spectrum of the complex 3 provided by the present invention in CDCl ₃ .

Figure 5 is the ¹³ C NMR spectrum of the ligand dcdp provided by the present invention in CDCl ₃ .

Figure 6 is the ³¹ P NMR spectrum of the ligand dcdp provided by the present invention in CDCl ₃ .

Figure 7 is the ³¹ P NMR spectrum of the complex 1 provided by the present invention in CDCl ₃ .

Figure 8 is the ³¹ P NMR spectrum of the complex 2 provided by the present invention in CDCl ₃ .

Figure 9 is the ³¹ P NMR spectrum of the complex 3 provided by the present invention in CDCl ₃ .

Figure 10 is the mass spectrum of the ligand dcdp provided by the present invention.

Figure 11 is the mass spectrum of complex 1 provided by the present invention.

Figure 12 is the mass spectrum of the complex 2 provided by the present invention.

Figure 13 is the mass spectrum of complex 3 provided by the present invention.

Figure 14 is the ORTEP diagram of the complexes 1-3 provided by the present invention.

Figure 15 is the ultraviolet absorption spectrum of the complex 1-3 and the ligand dcdp in CH ₂ Cl ₂ at 298K provided by the present invention.

FIG. 16 is the absorption spectrum of complex 1 in CH ₂ Cl ₂ calculated by TDDFT provided by the present invention.

FIG. 17 is the absorption spectrum of complex 2 in CH ₂ Cl ₂ calculated by TDDFT provided by the present invention.

FIG. 18 is the absorption spectrum of complex 3 in CH ₂ Cl ₂ calculated by TDDFT provided by the present invention.

Figure 19 is the frontier orbital diagram of complex 1 provided by the present invention in CH ₂ Cl ₂ .

Figure 20 is the frontier orbital diagram of complex 2 provided by the present invention in CH ₂ Cl ₂ .

Figure 21 is the frontier orbital diagram of complex 3 provided by the present invention in CH ₂ Cl ₂ .

Figure 22 is the normalized emission spectrum (298K and 77K) of the complexes 1-3 provided by the present invention in the solid state.

Figure 23 is a CIE diagram of complexes 1-3 provided by the present invention.

Fig. 24 is the HOMO and LUMO electron cloud distribution diagram of the optimized S ₀ configuration of the complexes 1-3 provided by the present invention.

Figure 25 is the HOMO and LUMO electron cloud distribution diagrams of the optimized S ₁ configuration of the complexes 1-3 provided by the present invention.

Figure 26 Optimized configurations of complexes 1-3 (S ₀ , S ₁ and T ₁ states).

Figure 27 Figure 23 is the room temperature luminescence lifetime (a: 1; b: 2; c: 3) of the complexes 1-3 provided by the present invention.

Detailed ways

The principles and features of the present invention are described below, and the examples are only used to explain the present invention, but not to limit the scope of the present invention.

1.1 Instruments and Reagents

Reagents: All reagents are commercially available and of analytical grade. Diethyl ether (Et ₂ O) solvent was soaked in sodium wire to remove water for 24h before use. Tetrahydrofuran (THF) was re-distilled after removing water with sodium wire for 24 hours, and benzophenone was used as an indicator.

Apparatus: Infrared spectrum adopts BX FT-IR Fourier transform infrared spectrometer (potassium bromide tablet) of Perkin Elmet Company, USA, ¹ H, ¹³ C and ³¹ P NMR spectrum adopts Varian 400MHz NMR spectrometer, using deuterium band reagent lock field and reference, chemical shifts are measured in ppm, H spectrum is based on SiMe ₄ standard, and phosphorus spectrum is based on 85% H ₃ PO ₄ standard. High-resolution mass spectrometry was performed using an HRMS-ESI mass spectrometer. The single crystal structures of the complexes were obtained using a Bruker APEX DUO diffractometer. The UV-Vis spectrum was performed with a Unicam Heλiosα spectrometer, and the photoluminescence spectrum was performed with a FLS980 steady-state and time-resolved fluorescence spectrometer. Solid-state quantum efficiency The absolute quantum efficiency was determined using a Hamamatsu system equipped with an integrating sphere. Thermogravimetric analysis was performed using a Perkin-Elmer DiamondTG/DTA thermal analyzer.

1.2 Synthesis

1.2.1 Synthesis of ligand dcdp

The reaction flask containing 1,2-dicarbazolyl-4,5-dibromobenzene (2.8315 g, 5.0 mmol) was evacuated, purged with nitrogen, and 30 mL of anhydrous ether (Et ₂ O) and 30 mL of tetrahydrofuran (THF) were added. ), slowly drop 6mL n-butyllithium in n-hexane solution (2.5mol/L, 15mmol) at -95°C, keep the temperature at -85～-95°C, stir and react for 1.5h and add chlorodiphenylphosphine ( 3.8mL, 20mmol), continue to stir for 2h, slowly rise to room temperature, add 30mL of water to quench the reaction, add dichloromethane to extract the reaction solution, obtain an organic phase after separation, dry with anhydrous sodium sulfate, filter, and remove the solvent to obtain the crude product , and separated by column chromatography to obtain 1.85 g of white solid, with a yield of 46.4%. ¹ H NMR (400 MHz, CDCl ₃ ): δ=7.70 (d, J=8.0 Hz, 4H), 7.54 (t, J=8.0 Hz, 2H), 7.36-7.28 (m, 20H), 6.97 (t, J =16.0Hz, 4H), 6.88(t, J=16.0Hz, 4H), 6.79(d, J=8.0Hz, 4H). ³¹ P NMR (160MHz, CDCl ₃ ), δ=-14.92(s). ¹³ C NMR(100MHz,CDCl ₃ )：δ＝144.56,144.47,144.38,139.02,136.54,136.51,136.49,135.71,135.68,135.64,133.95,133.85,133.75,133.70,128.93,128.76,128.73,128.69,125.31,123.48 ,120.08,119.75,109.52.HRMS(ESI):m/z calcd for[M+1] ⁺ ,777.2544,found:777.2555.

1.2.2 Synthesis of complex 1

At room temperature, cuprous iodide (95.23 mg, 0.5 mmol) was added to a solution of dcdp (388.43 mg, 0.5 mmol) in 30 mL of dichloromethane, stirred for 4 hours, filtered, and the filtrate was collected and spin-dried, and then 2 It was recrystallized from methyl chloride and n-hexane, and 312.1 mg of yellow solid powder was obtained after vacuum drying, and the yield was 64.5%. ¹ H NMR (400MHz, CDCl ₃ ): δ=7.71～7.68 (m, 12H), 7.44～7.40 (m, 16H), 7.23 (t, J=8.0Hz, 8H), 7.14 (t, J=8.0Hz) , 16H), 6.97 (t, J=8.0Hz, 8H), 6.88 (t, J=8.0Hz, 8H), 6.81 (d, J=8.0Hz, 8H). ³¹ P NMR (160MHz, CDCl ₃ ), δ=-22.43(s).HRMS(ESI): m/z calcd for [M-2I-Cu] ⁺ , 1616.4350, found: 1616.4356.

1.2.3 Synthesis of complex 2

The synthesis of complex 2 was similar to that of complex 1. At room temperature, cuprous bromide (71.7 mg, 0.5 mmol) was added to a solution of dcdp (388.43 mg, 0.5 mmol) in 30 mL of dichloromethane, stirred, filtered, and collected. The filtrate was spin-dried to obtain 285.5 mg of yellow solid powder, which was then recrystallized with dichloromethane and n-hexane, and the yield was 62.1% after vacuum drying. ¹ HNMR (400MHz, CDCl ₃ ): δ=7.72～7.66(m, 12H), 7.48～7.42(m, 16H), 7.21(t, J=16.0Hz, 8H), 7.14(t, J=8.0Hz, 16H), 6.97 (t, J=8.0Hz, 8H), 6.88 (t, J=8.0Hz, 8H), 6.80 (d, J=8.0Hz, 8H). ³¹ P NMR (160MHz, CDCl ₃ ), δ =-19.95(s).HRMS(ESI): m/zcalcd for [M-2Br-Cu] ⁺ , 1616.4350, found: 1616.4367.

1.2.4 Synthesis of complex 3

The synthesis of complex 3 is similar to that of complex 1. At room temperature, cuprous chloride (49.5 mg, 0.5 mmol) was added to a solution of dcdp (388.43 mg, 0.5 mmol) in 30 mL of dichloromethane, stirred, filtered, and collected. The filtrate was spin-dried to obtain 261.3 mg of yellow solid powder, which was then recrystallized from dichloromethane and n-hexane, and the yield was 59.7% after vacuum drying. ¹ HNMR (400MHz, CDCl ₃ ): δ=7.72～7.66(m, 12H), 7.50～7.43(m, 16H), 7.21(t, J=8.0Hz, 10H), 7.15(t, J=8.0Hz, 14H), 6.98 (t, J=8.0Hz, 8H), 6.88 (t, J=8.0Hz, 8H), 6.79 (d, J=8.0Hz, 8H). ³¹ P NMR (160MHz, CDCl ₃ ), δ =-18.36(s).HRMS(ESI): m/zcalcd for [M-2Cl-Cu] ⁺ , 1616.4350, found: 1616.4339.

2. Results and Discussion

2.1 Synthesis and structural characterization

The synthetic routes of ligand dcdp and complexes 1-3 are shown in Scheme 1. First, 1,2-difluoro-4,5-dibromobenzene and carbazole were mixed under basic conditions of cesium carbonate, and N,N-dimethylformamide (DMF) was used as solvent, and the reaction was carried out at 160 °C to generate 1, 2-Dicarbazole-4,5-dibromobenzene, yield 69.2%, and then reacted with n-butyllithium at a molar ratio of 1:2.5 in a mixed solution of anhydrous ether and tetrahydrofuran at -95°C under nitrogen atmosphere 1,2-dilithium-4,5-dicarbazolylbenzene was generated, and then continued to react with chlorodiphenylphosphine to obtain the ligand dcdp in a yield of 46.4%. The ligands dcdp and CuX were reacted in CH ₂ Cl ₂ at a molar ratio of 1:1 to obtain binuclear cuprous halide complexes 1-3 in 59.7-64.5% yield, and the complexes were stable in air and soluble in dichloride Methane, chloroform and other organic solvents. The structure of the complex was confirmed by nuclear magnetic resonance, high-resolution mass spectrometry and single crystal X-ray diffraction. The synthetic route of complexes 1-3 is shown in Figure 1.

2.1.1. ¹ H NMR spectrum

Figures 1 to 4 are the H NMR spectra of ligand dcdp and complexes 1-3 in CDCl ₃ deuterated reagent, respectively. The chemical shifts, integrals and splitting of peaks in the figures are consistent with the structure.

2.1.2. ¹³ C NMR spectrum

Figure 6 is the carbon nuclear magnetic spectrum of the ligand dcdp in deuterated chloroform. There are 13 carbon atoms with different chemical environments, indicating that the ligand structure has symmetry, which is consistent with the structure.

2.1.3. ³¹ P NMR spectrum

Figures 7 to 10 are divided into the NMR spectra of ligand dcdp and complexes 1-3 in CDCl ₃ . There are 2 P atoms in the ligand dcdp, and 4 P atoms in the complexes 1-3, respectively. The 4 NMR spectra have only one set of signal peaks, indicating that their structures are symmetrical.

2.1.4.HRMS-ESI spectrum

The ligand dcdp and complexes 1-3 were characterized by high-resolution electrospray ionization mass spectrometer (HRMS- ^ESI ). peak, which is consistent with the theoretical calculated value of 777.2544; the mass spectra of Figure 11-Figure 13 show that the molecular ion peaks of complexes 1-3 are not found, and fragment ion peaks with m/z of 1616.4356, 1616.4367 and 1616.4339 can be seen, corresponding to The complex removes two halogen atoms and one copper atom fragment ion peak [M-2X-Cu] ⁺ , which is consistent with the theoretical calculated value of 1616.4350.

2.1.5. Crystal structure

配合物2和3中Cu…Cu之间的距离分别为

和

与铜原子的范德华半径之和

相比，表明配合物1中铜与铜之间形成共价键，而配合物2和3中2个铜原子间有弱的作用力。The structures of complexes 1-3 are shown in Figure 14. Crystal data and some bond length and angle data are listed in Tables 1 and 2. There is one solvent dichloromethane molecule in complex 3. The crystal data show that the complexes 1-3 have a binuclear structure, the copper center is a curved tetrahedron configuration, each copper atom is connected with 2 P atoms and 2 halogens, respectively, and the 2 halogens are bridged with 2 Cu atoms. Cu ₂ X ₂ structural unit, the Cu ₂ X ₂ ring is bent along the X...X axis. The dihedral angle between the two CuX ₂ planar triangles is 23.53° to 37.04°. The Cu–X bond length in complexes 1-3 increases with the increase of the halogen van der Waals radius, and the distance between Cu…Cu in complex 1 is

The distances between Cu…Cu in complexes 2 and 3, respectively, are

and

and the sum of the van der Waals radii of copper atoms

In comparison, it shows that the covalent bond is formed between copper and copper in complex 1, while there is a weak interaction between the two copper atoms in complexes 2 and 3.

Table 1. Crystal data for complexes 1-3

与键角(°)Table 2. Partial bond lengths of complexes 1-3

and bond angle (°)

2.2. Photophysical properties and molecular orbital calculations

Figure 15 is the UV-Vis absorption spectra of complexes 1-3 and their ligand _dcdp in _CH2Cl2 solution at room temperature. The concentration of ligands and complexes was 2.5×10 ^-5 mol/L. The ligand dcdp has maximum absorption peaks at 293nm (ε=3.68×10 ⁴ M ^-1 cm ^-1 ) and 339 nm (ε=2.35×10 ⁴ M ^-1 cm ^-1 ), which are the characteristic absorptions of aromatic phosphine compounds, respectively. Corresponding to the transitions of π→π* and n→π*, the former is the transition of π electrons in the carbazole or benzene ring to the antibonding π* orbital, and the latter is the transition of lone pair electrons on the P atom or nitrogen atom to carbazole Transitions of the antibonding π* orbital of a ring or benzene ring. Complexes 1-3 appeared strong at 291～292 nm [ε=(4.96～6.32)×10 ⁴ M ^-1 cm ^-1 ] and 337 nm [ε=(4.59～5.83)×10 ⁴ M ^-1 cm ^-1 ] There is a weak absorption tail band at 375-445 nm. This weak absorption tail is due to copper-to-ligand, halogen-to-ligand, or charge transitions within the ligand. Through TDDFT calculation, the absorption spectra of complexes 1 to 3 in dichloromethane are shown in Figures 16 to 18, and the calculated results are consistent with the experimental results. According to the excited state properties of complexes 1-3 (Tables 3 to 5, Figures 19-21), the main contribution of the lowest excited state of complexes 1-3 comes from HOMO (highest occupied molecular orbital) to LUMO (LUMO: the lowest unoccupied molecular orbitals). As shown in Figures 19-21, the optimized S ₀ configuration and the molecular orbital diagrams of the HOMO and LUMO of complexes 1 to 3 calculated by DTF show that the electrons on the HOMO are mainly distributed on the copper, halogen and phosphorus atoms, while the LUMO The electrons are mainly distributed on the benzene ring of the ligand dcdp and the nitrogen ring of carbazole. Therefore, we can infer that the lowest excited states of complexes 1-3 are composed of MLCT (metal-to-ligand charge transition), XLCT (halogen-to-ligand charge transition) and ILCT (intra-ligand charge transition).

Table 3. Calculated excited states of complex ₁ in _CH2Cl2

Table 4. Calculated excited states of complex ₂ in _CH2Cl2

Table 5. Calculated excited states of complex ₃ in _CH2Cl2

Figure 22 shows the solid-state emission spectra of complexes 1-3 (from left to right) at 293K and 77K, and Table 3 shows the maximum emission wavelengths, lifetimes at 298K and 77K, quantum efficiencies and structures obtained by X-ray analysis using TDDFT calculations The data. Complexes 1, 2, and 3 emit green-yellow, yellow, and yellow-orange light at room temperature, with maximum emission wavelengths of 567, 580, and 602 nm (excitation wavelength of 365 nm), respectively, with broad emission spectra and no structural features, indicating that The emitting excited state has a charge transfer characteristic. The solid-state absolute internal quantum efficiency Φ _PL is 0.09-0.53 at room temperature in air. The maximum emission wavelengths of 1-3 are in the order 3>2>1, which is the same as the order of the field strength of halogens (I ^- >Br ^- >Cl ^- ). Based on the solid-state fluorescence spectra at 298K, the chromaticity coordinates of complexes 1-3 were (0.4624, 0.5183), (0.4832, 0.5012), and (0.5326, 0.4612), respectively (Figure 23). At 298K, the radiation decay rate (k _r ) of the complexes 1-3 is 7.5×10 ⁴ ～2.4×10 ⁵ s ^-1 , and the luminescence lifetime is 1.2-2.3μs, which is shorter than the lifetime at 77K (139～818μs) 2 orders of magnitude, indicating that 1-3 luminescence is thermally activated delayed fluorescence (TADF). At 77K, the emission maxima of complexes 1-3 are 569, 585 and 606 nm (excitation wavelength is 365 nm), and the emission band has a weaker red shift compared with the maximum emission wavelength at room temperature, which is due to the lower emission at low temperature. The excited state (T ₁ ) of the energy level dominates. Table 3 shows the singlet and triplet energy levels and ΔE(S ₁ -T ₁ ) of complexes 1–3 calculated and analyzed using natural bond orbitals (NBO). The energy level differences of S ₁ and T ₁ of complexes 1–3 are 0.0723, 0.0898 and 0.1067 eV, respectively, and the energy level difference is less than 0.37 eV, which provides further evidence for the TADF effect of complexes 1–3.

Based on the optimized S ₁ geometry of these complexes and the frontier orbital maps of the HOMO and LUMO, the emission properties were also calculated using TDDFT. The calculated results indicate that the luminescence of complexes 1–3 mainly originates from the electronic transition from LUMO to HOMO. The LUMO and HOMO frontier orbital diagrams in the S ₁ state are shown in Fig. 24. It can be seen from the figure that the electrons in the complex HOMO are mainly concentrated on Cu, halogen and P, and the electrons in the LUMO are mainly concentrated in the ligand, which indicates that the luminescence of the complexes 1–3 mainly comes from XLCT (the charge of the halogen to the ligand). transition), MLCT (metal-to-ligand charge transition), and ILCT intra-ligand charge transition (intra-ligand charge transition).

The coordination configurations of the Cu centers in S ₀ , S ₁ and T ₁ optimized by TDDFT calculations are shown in Fig. 25 . In the S ₀ , S ₁ and T ₁ configurations, the bond angle of the bis-P ligand to the copper center (P-Cu-P) changes little, which is attributed to the rigidity of the bis-phosphine ligand dcdp. From the change of bond length and bond angle, it can be seen that from S ₀ configuration to S ₁ and T ₁ configuration, the deformation of complex 1 is the smallest, so complex 1 has a higher quantum efficiency than complexes 2 and 3. The sum of the bond angles of the S ₁ and T ₁ configurations of the complexes 1-3 with copper as the center is changed compared with the sum of the bond angles of the S ₀ configuration (1:-0.32～1.87°, 0.79～2.65°; 2: 2.06～5.45°,-16.31～2.98°; 3:-6.39～10.79°,-2.43～-5.87°). The more variable bond angles are P-Cu-X, X-Cu-X and P3-Cu-X, which lead to the Jahn-Teller distortion upon excitation.

Table 6. Photophysical data of complexes 1-3 in the solid state.

^a Maximum emission peak wavelength.

^b Luminescence lifetime, experimental error ±5%.

^cAbsolute quantum efficiency in air, experimental error ±5%.

^d Radiation decay rate constant, k _r =Ф/τ

^e TDDFT calculation of the energy obtained from vertical excitation (the energy levels of S ₁ and T ₁ , and the energy level difference between S ₁ and T ₁ )

The optimized configurations (S ₀ , S ₁ and T ₁ states) of the complexes 1-3 provided by the present invention are shown in FIG. 26 .

The room temperature luminescence lifetimes (a: 1; b: 2; c: 3) of the complexes 1-3 provided by the present invention are shown in FIG. 27 .

The invention provides a novel rigid carbazole phenyl bisphosphine ligand and three cuprous halide complexes. Complexes 1, 2 and 3 emit green-yellow to yellow-orange light in solid state at room temperature, with maximum emission wavelengths of 567, 580 and 602 nm, respectively. The solid-state absolute internal quantum efficiency Φ _PL is 0.09-0.53 at room temperature in air, and the luminescence lifetime is 1.2-2.3 μs. The luminescence of complexes 1-3 is thermally activated delayed fluorescence, mainly from XLCT (halogen to ligand charge transition), MLCT (charge transition from metal to ligand) and ILCT intra-ligand charge transition (intra-ligand charge transition), ligand dcdp and three complexes have not been reported. The luminescence lifetime of the complex is the lowest among the currently reported binuclear cuprous halide complexes. The low luminescence lifetime is beneficial to reduce the quenching effect of photoexcitons at high concentrations and improve the external quantum efficiency of OLEDs. The low-lifetime, high-efficiency luminescent complexes can be applied to OLED devices as luminescent materials.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection of the present invention. within the range.

Claims (9)

1. A4, 5-dicarbazole phenyl diphosphine ligand is characterized in that the structural formula is as follows:

2. a process for the preparation of 4, 5-dicarbazolylphosphine ligands according to claim 1, wherein the synthesis route is as follows:

3. the carbazole phenyl diphosphine cuprous halide is characterized by having a structural formula as follows:

4. a process for the preparation of cuprous halide of carbazole phenyl bisphosphine according to claim 3, characterized in that its synthetic route is as follows:

5. use of cuprous halide of carbazole phenyl bisphosphine according to claim 3, characterized in that: as a fluorescent material.

6. Use according to claim 5, characterized in that: as a thermally activated delayed fluorescence material.

7. Use according to claim 5, characterized in that: x is I, and the carbazole phenyl diphosphine cuprous halide is used as a green yellow light fluorescent material.

8. Use according to claim 5, characterized in that: x is Br, and the carbazole phenyl diphosphine cuprous halide is used as a yellow light fluorescent material.

9. Use according to claim 5, characterized in that: x is Cl, and the carbazole phenyl diphosphine cuprous halide is used as a yellow orange light fluorescent material.

Images