Alkyl chain modified metal organic iridium complex and its preparation method and use

Abstract

The present invention discloses an alkyl chain-modified metal organic iridium complex, a preparation method and uses thereof, and relates to the technical field of organic photoelectric functional materials. Compared with the prior art, the iridium complex prepared by the present invention not only has a novel chemical structure and a mature and reliable preparation route, but also can change the hydrophobicity of the molecule through modification of the alkyl chain, effectively regulating the luminescence performance of the molecule. The luminescence intensity of the iridium complex is high in a high-concentration solution or in an aggregated state, and therefore has broad application value in the fields of biological cell imaging, organic light-emitting diode devices, chemical probes, optical films, etc.

Description

Technical field:

[0001] The present invention relates to the technical field of organic photoelectric functional materials, and in particular to an alkyl chain-modified metal organic iridium complex, a preparation method thereof, and uses thereof. Background technology:

[0002] Aggregation-induced emission effectively addresses the fluorescence quenching problem of organic molecules and overcomes practical application difficulties of organic light-emitting materials, playing a constructive role in the design, synthesis, and practical application of organic light-emitting materials. Overall, aggregation-induced emission has become a hot research area pioneered by Chinese researchers and has been widely applied in various fields in real life, such as medical treatment, biological detection, cell imaging, and light-emitting devices.

[0003] Organometallic iridium complexes are currently among the most outstanding organic light-emitting materials and have been a hot topic in organic light-emitting material research over the past 20 years. They possess high luminescence efficiency, good thermal stability, and easily tunable emission color. Iridium complexes exhibiting aggregation-induced emission (AIE) properties, which exhibit strong phosphorescence, stable luminescence, large Stokes shifts, minimal background interference, minimal photodamage to biological samples, and sensitive detection. They hold great promise for applications in biochemistry and bioassays and diagnostics. Therefore, the design and synthesis of AIE-enabled iridium complexes is highly desirable. Summary of the invention:

[0004] The technical problem to be solved by the present invention is to provide an alkyl chain-modified metal organic iridium complex and a preparation method thereof. By using a long alkyl chain to structurally modify the auxiliary ligand of the iridium complex, a hydrophobic molecular structure is designed and synthesized, which can effectively regulate the photophysical properties of the complex, especially the aggregation-induced emission properties.

[0005] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0006] The first object of the present invention is to provide an alkyl chain-modified metal organic iridium complex, the structural formula of which is shown below:

[0007]

[0008] Here, n is an integer ranging from 1 to 15.

[0009] The second object of the present invention is to provide a method for preparing the aforementioned alkyl chain-modified metal organic iridium complex, comprising the following steps:

[0010] (1) reacting 2-(2-pyridyl)benzimidazole with a dihalogenated linear alkane to obtain a haloalkyl-2-(2-pyridyl)-benzimidazole;

[0011] (2) reacting a haloalkyl-2-(2-pyridyl)benzimidazole with 3,6-di-tert-butylcarbazole to obtain a 2-(2-pyridyl)benzimidazole modified with a 3,6-di-tert-butylcarbazole linear alkyl group;

[0012] (3) reacting 4-(2-pyridyl)-benzaldehyde with iridium trichloride to obtain a chloro-bridged dimer of iridium containing a 4-(2-pyridyl)-benzaldehyde ligand;

[0013] (4) 2-(2-pyridyl)benzimidazole modified with a linear alkyl group of 3,6-di-tert-butylcarbazole is reacted with a chloro-bridged dimer of iridium containing a 4-(2-pyridyl)-benzaldehyde ligand and KPF6 to obtain an alkyl chain-modified metal organic iridium complex.

[0014] The third object of the present invention is to provide the use of the aforementioned alkyl chain-modified metal organic iridium complex as an aggregation-induced emission material.

[0015] A fourth object of the present invention is to provide applications of the aforementioned aggregation-induced emission materials in biological cell imaging, organic light-emitting diode devices, chemical probes, and optical films.

[0016] The beneficial effects of the present invention are as follows: compared with the prior art, the iridium complex prepared by the present invention not only has a novel chemical structure and a mature and reliable preparation route, but also can change the hydrophobicity of the molecule through modification of the alkyl chain, effectively regulating the luminescence performance of the molecule. The luminescence intensity of the iridium complex is high in a high-concentration solution or in an aggregated state, and therefore has broad application value in the fields of biological cell imaging, organic light-emitting diode devices, chemical probes, optical films, etc. Description of the drawings:

[0017] Figure 1 Aggregation-induced emission properties of the linear pentyl-modified metal organic iridium complex prepared in Example 4 in a mixed solution of n-hexane and dichloromethane. Specific implementation method:

[0018] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific embodiments and illustrations.

[0019] The present invention provides an alkyl chain-modified metal organic iridium complex, the structural formula of which is shown below:

[0020]

[0021] Here, n is an integer ranging from 1 to 15.

[0022] The alkyl chain-modified metal organic iridium complex of the present invention is a cationic complex composed of two 4-(2-pyridyl)-benzaldehyde main ligands and a 2-(2-pyridyl)benzimidazole auxiliary ligand modified with a 3,6-di-tert-butylcarbazole linear alkyl group.

[0023] The present invention also provides a method for preparing the aforementioned alkyl chain-modified metal organic iridium complex, comprising the following steps:

[0024] (1) reacting 2-(2-pyridyl)benzimidazole with a dihalogenated linear alkane to obtain a haloalkyl-2-(2-pyridyl)-benzimidazole;

[0025] (2) reacting a haloalkyl-2-(2-pyridyl)benzimidazole with 3,6-di-tert-butylcarbazole to obtain a 2-(2-pyridyl)benzimidazole modified with a 3,6-di-tert-butylcarbazole linear alkyl group;

[0026] (3) reacting 4-(2-pyridyl)-benzaldehyde with iridium trichloride to obtain a chloro-bridged dimer of iridium containing a 4-(2-pyridyl)-benzaldehyde ligand;

[0027] (4) 2-(2-pyridyl)benzimidazole modified with a linear alkyl group of 3,6-di-tert-butylcarbazole is reacted with a chloro-bridged dimer of iridium containing a 4-(2-pyridyl)-benzaldehyde ligand and KPF6 to obtain an alkyl chain-modified metal organic iridium complex.

[0028] Preferably, the reaction temperature in step (1) is 0-40°C.

[0029] Preferably, the molar ratio of 2-(2-pyridyl)benzimidazole to dihalogenated linear alkane in step (1) is 1:(1.0-1.5), wherein the dihalogenated linear alkane is a linear alkane containing halogen at both ends.

[0030] Preferably, the reaction temperature in step (2) is 100-120°C.

[0031] Preferably, the molar ratio of the haloalkyl-2-(2-pyridyl)benzimidazole to 3,6-di-tert-butylcarbazole in step (2) is 1:(1.0-1.5).

[0032] Preferably, the reaction in step (1) and step (2) is carried out in the presence of a strong base. The strong base is at least one of sodium hydride, potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium phosphate, cesium fluoride, cesium carbonate, sodium acetate, and sodium ethoxide. Other strong bases known in the art may also be used.

[0033] Further preferably, the molar ratio of 2-(2-pyridyl)benzimidazole to the strong base in step (1) is 1:(10.0-15.0).

[0034] Further preferably, the molar ratio of the haloalkyl-2-(2-pyridyl)benzimidazole to the strong base in step (2) is 1:(0.3-0.6).

[0035] Preferably, the reaction temperature in step (3) is 120-130°C.

[0036] Preferably, the molar ratio of 4-(2-pyridyl)-benzaldehyde to iridium trichloride in step (3) is (1-2.5):1.

[0037] Preferably, the molar ratio of 2-(2-pyridyl)benzimidazole modified with 3,6-di-tert-butylcarbazole linear alkyl, iridium chloride-bridged dimer containing 4-(2-pyridyl)-benzaldehyde ligand, and KPF6 in step (4) is 1:(2.0-2.5):(2.0-4.0).

[0038] Preferably, the reaction temperature in step (4) is 100-120°C.

[0039] The present invention also provides the use of the aforementioned alkyl chain-modified metal organic iridium complex as an aggregation-induced emission material. Utilizing the aggregation-induced emission properties of the aforementioned alkyl chain-modified metal organic iridium complex, the complex is applied to the preparation of an aggregation-induced emission material.

[0040] The present invention also provides applications of the aforementioned aggregation-induced luminescence material in the fields of biological cell imaging, organic light-emitting diode devices, chemical probes, optical films, and the like.

[0041] Example 1

[0042] Synthesis of 5-bromopentyl-2-(2-pyridyl)benzimidazole:

[0043] Sodium hydride (10.00 mmol, 0.24 g) was added to a 100 mL reaction flask. The oxygen in the flask was replaced with nitrogen, and the reaction apparatus was placed in an ice bath. 2-(2-pyridyl)benzimidazole (1.00 mmol, 0.19 g) was dissolved in 30 mL of dry tetrahydrofuran and slowly injected into the reaction flask over approximately 2 hours. During the reaction, the solution gradually turned brick red. After the reaction was complete, the temperature was raised to room temperature and stirred with a magnetic stirrer for approximately 24 hours. After stirring, 1,5-dibromopentane (1.00 mmol, 0.34 g) was rapidly injected into the reaction system all at once. The system was heated to 90°C and allowed to react for 20 hours. After the reaction, the product was dissolved in dichloromethane, separated by water, and the organic phase was rotary evaporated and separated by column chromatography to yield a yellow, viscous, transparent, and jellylike product. 1H NMR(400MHz, CDCl3)δ(ppm):8.69(d,J=4.6Hz,1H),8.42(d,J=8.0Hz,1H),7.86–7.82(m,2H),7.44–7.43 (m,1H),7.36–7.29(m,3H),4.85–4.81(m,2H),3.42–3.36(m,2H),1.97–1.86(m,4H),1.56–1.48(m,2H).

[0044]

[0045] Example 2

[0046] Synthesis of 2-(2-pyridyl)benzimidazole modified with linear pentyl of 3,6-di-tert-butylcarbazole:

[0047] 5-Bromopentyl-2-(2-pyridyl)benzimidazole (1.00 mmol, 0.34 g) prepared in Example 1 was added to a round-bottom flask, followed by 3,6-di-tert-butylcarbazole (1.00 mmol, 0.28 g), potassium hydroxide (0.40 mmol, 0.03 g), and 20 mL of toluene. The mixture was reacted in an oil bath at 110°C under nitrogen atmosphere for 20 h. After the reaction, the mixture was dissolved in dichloromethane, separated by adding water, extracted, and separated by rotary evaporation. The product was then separated by column chromatography (the stationary phase was 300-400 mesh silica gel, and the eluent was dichloromethane and petroleum ether in a volume ratio of 1:1) to obtain the product. 1 H NMR (400MHz, CDCl3) δ (ppm): 8.65–8.64 (m, 1H), 8.41 (d, J = 8.0Hz, 1H), 8.15 (d, J = 1.6Hz, 2H), 7.89–7.87 (m, 1H), 7.82–7.78 (m, 1H), 7.55–7. 53(m,2H),7.44–7.43(m,1H),7.36–7.27(m,5H),4.83–4.79(m,2H),4 .25–4.22(m,2H),1.90–1.82(m,4H),1.66–1.63(m,2H),1.50(s,18H).

[0048]

[0049] Example 3

[0050] Synthesis of iridium chloride-bridged dimers containing 4-(2-pyridyl)-benzaldehyde ligands:

[0051] To a 100 mL three-necked flask, add 4-(2-pyridyl)-benzaldehyde (0.57 g, 3.15 mmol), iridium trichloride (1.86 g, 1.57 mmol), 30 mL of ethylene glycol monomethyl ether, and 10 mL of water. Under nitrogen, heat to 120°C and reflux for reaction. After the reaction, remove the solvent to obtain the product. 1 H NMR(400MHz, DMSO-d6)δ(ppm):9.82–9.72(m,4H),8.50–8.45(m,4H),8.35–8.11(m,4H),8.08–7.89(m,8H),7.62–7.02(m,8H),6.85–6.92(m,4H).

[0052]

[0053] Example 4

[0054] Synthesis of linear pentyl-modified metal organic iridium complexes:

[0055] The iridium chloride-bridged dimer containing 4-(2-pyridyl)-benzaldehyde ligand (0.40mmol, 4.70g) and the 3,6-di-tert-butylcarbazole linear pentyl-modified 2-(2-pyridyl)benzimidazole (0.20mmol, 0.88g) prepared in Example 2 were added to 20mL of ethylene glycol monoethyl ether, the oil bath temperature was controlled at 120°C, and nitrogen was introduced to react for about 12h. After the reaction was completed, it was cooled to room temperature and KPF6 (0.20mmol, 0.37g) was added. After washing with deionized water, the crude product was extracted with dichloromethane to obtain a crude product, which was separated by column chromatography (the stationary phase was 300-400 mesh silica gel, with dichloromethane and petroleum ether in a volume ratio of 1:1 as eluent) to obtain the product. 1H NMR (400MHz, CDCl3) δ (ppm): 9.75 (d, J = 9.2Hz, 2H), 8.51 (d, J = 8.0Hz, 1H), 8.32–8.28 (m, 1H), 8.10 (d, J = 1.6Hz, 2H), 8.04(d,J=8.0Hz,1H),7.96–7.92(m,2H),7.87–7.81(m,3H),7.75–7.71(m,1H),7.64(d,J=5.2Hz,1H),7.61–7.56(m, 3H),7.46–7.40(m,4H),7.36–7.32(m,1H),7.28–7.24(m,2H),7.18–7.14(m,1H),7.02–6.98(m,2H),6.81–6.72(m,2 H),6.24(d,J=8.4Hz,1H),4.88–4.75(m,2H),4.30–4.21(m,2H),2.09–1.93(m,4H),1.63–1.59(m,2H),1.46(s,18H).

[0056]

[0057] Example 5

[0058] Synthesis of 6-bromohexyl-2-(2-pyridyl)benzimidazole:

[0059] Example 5 differs from Example 1 in that 0.34 g of 1,5-dibromopentane is replaced by 0.36 g of 1,6-dibromohexane. 1 H NMR (400MHz, CDCl3) δ (ppm): 8.70–8.69 (m, 1H), 8.42 (d, J = 8.0Hz, 1H), 7.87–7.83 (m, 2H), 7.46–7.44 ( m,1H),7.37–7.31(m,3H),4.85–4.81(m,2H),3.38–3.34(m,2H),1.92–1.78(m,4H),1.49–1.36(m,4H).

[0060]

[0061] Example 6

[0062] Synthesis of 2-(2-pyridyl)benzimidazole modified with 3,6-di-tert-butylcarbazole linear hexyl group:

[0063] Example 6 differs from Example 2 in that 0.34 g of 5-bromopentyl-2-(2-pyridyl)-benzimidazole is replaced with 0.36 g of 6-bromohexyl-2-(2-pyridyl)benzimidazole.1 H NMR (400MHz, CDCl3) δ (ppm): 8.55 (d, J = 4.7Hz, 1H), 8.38 (d, J = 8.0Hz, 1H), 8.09 (d, J = 1.7Hz, 2H), 7.84–7.78 (m, 2H), 7.49–7.46 (m ,2H),7.40–7.36(m,1H),7.32–7.23(m,5H),4.81–4.77(m,2H),4.21–4.18(m,2H),1.89–1.77(m,4H),1.67(s,2H),1.45(s,20H).

[0064]

[0065] Example 7

[0066] Synthesis of linear hexyl-modified organometallic iridium complexes:

[0067] Example 7 differs from Example 4 in that 0.88 g of 3,6-di-tert-butylcarbazole linear pentyl-modified 2-(2-pyridine)benzimidazole is replaced by 0.46 g of 3,6-di-tert-butylcarbazole linear hexyl-modified 2-(2-pyridine)benzimidazole. 1 HNMR(400MHz,DMSO-d6)δ(ppm):9.75(d,J=8.0Hz,2H),8.51–8.47(m,1H),8.22–8.11(m,3H),8.04–7.28(m,19H),7.02–6.97 (m,2H),6.81–6.72(m,2H),6.29–6.23(m,1H),4.26–4.22(m,2H),3.50–3.39(m,2H),1.98–1.83(m,4H),1.46–1.44(m,22H).

[0068]

[0069] Example 8

[0070] Synthesis of 7-bromoheptyl-2-(2-pyridyl)benzimidazole:

[0071] Example 8 differs from Example 1 in that 0.34 g of 1,5-dibromopentane is replaced by 0.50 g of 1,7-dibromoheptane. 1H NMR (400MHz, CDCl3) δ (ppm): 8.68 (d, J = 0.4Hz, 1H), 8.40 (d, J = 8.0Hz, 1H), 7.86–7.82 (m, 2H), 7.46–7.43 (m,1H),7.35–7.28(m,3H),4.84–4.81(m,2H),3.38–3.35(m,2H),1.90–1.77(m,4H),1.40–1.31(m,6H).

[0072]

[0073] Example 9

[0074] Synthesis of 2-(2-pyridyl)benzimidazole modified with 3,6-di-tert-butylcarbazole linear heptyl group:

[0075] Example 9 differs from Example 2 in that 0.34 g of 5-bromopentyl-2-(2-pyridyl)benzimidazole is replaced by 0.36 g of 7-bromoheptyl-2-(2-pyridyl)benzimidazole. 1 H NMR (400MHz, CDCl3) δ (ppm): 8.62–8.60 (m, 1H), 8.43 (d, J = 8.0Hz, 1H), 8.14 (d, J = 1.6Hz, 2H), 7.90–7.83 (m, 2H), 7.53–7. 51(m,2H),7.42–7.27(m,6H),4.84–4.81(m,2H),3.38–3.35(m,2H),1.90–1.77(m,4H),1.40–1.31(m,6H),1.50(s,18H).

[0076]

[0077] Example 10

[0078] Synthesis of linear heptyl-modified organometallic iridium complexes:

[0079] Example 10 differs from Example 4 in that 0.88 g of 3,6-di-tert-butylcarbazole linear pentyl-modified 2-(2-pyridine)benzimidazole is replaced by 0.55 g of 3,6-di-tert-butylcarbazole linear heptyl-modified 2-(2-pyridine)benzimidazole. 1HNMR(400MHz,DMSO-d6)δ(ppm):9.75(d,J=8.0Hz,2H),8.48(d,J=8.0Hz,1H),8.26–8.22(m,1H),8.12(d,J=1.6Hz ,2H),8.04(d,J=8.4Hz,1H),7.96(d,J=5.6Hz,1H),7.89–7.73(m,6H),7.67–7.56(m,4H),7.53–7.48(m,3H),7.42– 7.35(m,2H),7.31(s,1H),7.13–7.10(m,1H),7.06–6.97(m,2H),6.81(d,J=1.2Hz,1H),6.73(d,J=1.2Hz,1H),6.24 (d,J=8.4Hz,1H),4.86–4.78(m,2H),4.23–4.20(m,2H),2.07–1.79(m,6H),1.62–1.60(m,2H),1.48–1.46(m,20H).

[0080]

[0081] Example 11

[0082] Synthesis of 8-bromooctyl-2-(2-pyridyl)benzimidazole:

[0083] Example 11 differs from Example 1 in that 0.34 g of 1,5-dibromopentane is replaced by 0.36 g of 1,8-dibromooctane. 1 H NMR (400MHz, CDCl3) δ (ppm): 8.68 (d, J = 0.4Hz, 1H), 8.40 (d, J = 8.0Hz, 1H), 7.86–7.82 (m, 2H), 7.47–7.45 (m,1H),7.35–7.28(m,3H),4.84–4.81(m,2H),3.38–3.35(m,2H),1.88–1.73(m,4H),1.40–1.31(m,8H).

[0084]

[0085] Example 12

[0086] Synthesis of 3,6-di-tert-butylcarbazole linear octyl modified 2-(2-pyridyl)benzimidazole:

[0087] Example 12 differs from Example 2 in that 0.34 g of 5-bromopentyl-2-(2-pyridyl)benzimidazole is replaced by 0.46 g of 8-bromooctyl-2-(2-pyridyl)benzimidazole.1 H NMR (400MHz, CDCl3) δ (ppm): 8.62–8.60 (m, 1H), 8.43 (d, J = 8.0Hz, 1H), 8.14 (d, J = 1.6Hz, 2H), 7.90–7.83 (m, 2H), 7.53–7. 51(m,2H),7.42–7.27(m,6H),4.84–4.81(m,2H),3.38–3.35(m,2H),1.88–1.71(m,6H),1.40–1.31(m,6H),1.50(s,18H).

[0088]

[0089] Example 13

[0090] Synthesis of linear octyl-modified organometallic iridium complexes:

[0091] Example 13 differs from Example 4 in that 0.88 g of 3,6-di-tert-butylcarbazole linear pentyl-modified 2-(2-pyridine)benzimidazole is replaced with 0.55 g of 3,6-di-tert-butylcarbazole linear octyl-modified 2-(2-pyridine)benzimidazole. 1 HNMR(400MHz,DMSO-d6)δ(ppm):9.73(d,J=8.0Hz,2H),8.46(d,J=8.0Hz,1H),8.25–8.21(m,1H),8.12(d,J=1.6Hz ,2H),8.04(d,J=8.4Hz,1H),7.96(d,J=5.6Hz,1H),7.89–7.73(m,6H),7.67–7.56(m,4H),7.53–7.48(m,3H),7.42– 7.35(m,2H),7.31(s,1H),7.13–7.10(m,1H),7.06–6.97(m,2H),6.81(d,J=1.2Hz,1H),6.73(d,J=1.2Hz,1H),6.24 (d,J=8.4Hz,1H),4.86–4.78(m,2H),4.23–4.20(m,2H),2.07–1.79(m,6H),1.62–1.60(m,2H),1.46–1.42(m,22H).

[0092]

[0093] Example 14

[0094] Synthesis of 9-bromononyl-2-(2-pyridyl)benzimidazole:

[0095] Example 14 differs from Example 1 in that 0.34 g of 1,5-dibromopentane is replaced by 0.40 g of 1,8-dibromononane. 1 H NMR (400MHz, CDCl3) δ (ppm): 8.68 (d, J = 0.4Hz, 1H), 8.40 (d, J = 8.0Hz, 1H), 7.86–7.82 (m, 2H), 7.47–7.45 (m,1H),7.35–7.28(m,3H),4.84–4.81(m,2H),3.38–3.35(m,2H),1.88–1.73(m,6H),1.39–1.29(m,8H).

[0096]

[0097] Example 15

[0098] Synthesis of 2-(2-pyridyl)benzimidazole modified with 3,6-di-tert-butylcarbazole linear nonyl group:

[0099] Example 15 differs from Example 2 in that 0.34 g of 5-bromopentyl-2-(2-pyridyl)benzimidazole is replaced by 0.57 g of 9-bromononyl-2-(2-pyridyl)benzimidazole. 1 H NMR (400MHz, CDCl3) δ (ppm): 8.62–8.60 (m, 1H), 8.43 (d, J = 8.0Hz, 1H), 8.14 (d, J = 1.6Hz, 2H), 7.90–7.83 (m, 2H), 7.53–7.51 (m,2H),7.42–7.27(m,6H),4.84–4.81(m,2H),3.38–3.35(m,2H),1.88–1.71(m,6H),1.40–1.31(m,6H),1.51–1.49(s,20H).

[0100]

[0101] Example 16

[0102] Synthesis of linear nonyl-modified metal organic iridium complexes:

[0103] Example 16 differs from Example 4 in that 0.88 g of 3,6-di-tert-butylcarbazole linear pentyl-modified 2-(2-pyridine)benzimidazole is replaced by 0.53 g of 3,6-di-tert-butylcarbazole linear nonyl-modified 2-(2-pyridine)benzimidazole. 1HNMR(400MHz,DMSO-d6)δ(ppm):9.73(d,J=8.0Hz,2H),8.46(d,J=8.0Hz,1H),8.25–8.21(m,1H),8.12(d,J=1.6Hz ,2H),8.04(d,J=8.4Hz,1H),7.96(d,J=5.6Hz,1H),7.89–7.73(m,6H),7.67–7.56(m,4H),7.53–7.48(m,3H),7.42– 7.35(m,2H),7.31(s,1H),7.13–7.10(m,1H),7.06–6.97(m,2H),6.81(d,J=1.2Hz,1H),6.73(d,J=1.2Hz,1H),6.24 (d,J=8.4Hz,1H),4.86–4.78(m,2H),4.23–4.20(m,2H),2.07–1.79(m,6H),1.62–1.60(m,2H),1.47–1.40(m,24H).

[0104]

[0105] Example 17

[0106] The linear pentyl-modified metal organic iridium complex prepared in Example 4 was dissolved in a n-hexane / dichloromethane mixed solution, wherein the n-hexane content in the mixed solution was 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90%, respectively, to prepare a concentration of 10 -5 mol / L mixed solution, using fluorescence / phosphorescence emission spectrometer to test the aggregation-induced emission effect, the results are shown in Figure 1 .

[0107] from Figure 1 It can be seen that the luminescence intensity of the linear pentyl-modified metal organic iridium complex prepared in Example 4 in a mixed solution of n-hexane and dichloromethane increases continuously as the n-hexane content in the mixed solution increases from 0% to 90%, which is a typical aggregation-induced emission property.

[0108] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. An alkyl chain-modified metal organic iridium complex, characterized in that: The structural formula of the alkyl chain modified metal organic iridium complex is shown below: Here, n is an integer ranging from 1 to 15.

2. The method for preparing the alkyl chain-modified metal organic iridium complex according to claim 1, characterized in that: The following steps are involved: (1) reacting 2-(2-pyridyl)benzimidazole with a dihalogenated linear alkane to obtain a haloalkyl-2-(2-pyridyl)-benzimidazole; (2) reacting a haloalkyl-2-(2-pyridyl)benzimidazole with 3,6-di-tert-butylcarbazole to obtain a 2-(2-pyridyl)benzimidazole modified with a 3,6-di-tert-butylcarbazole linear alkyl group; (3) reacting 4-(2-pyridyl)-benzaldehyde with iridium trichloride to obtain a chloro-bridged dimer of iridium containing a 4-(2-pyridyl)-benzaldehyde ligand; (4) 2-(2-pyridyl)benzimidazole modified with a linear alkyl group of 3,6-di-tert-butylcarbazole is reacted with a chloro-bridged dimer of iridium containing a 4-(2-pyridyl)-benzaldehyde ligand and KPF6 to obtain an alkyl chain-modified metal organic iridium complex.

3. The preparation method according to claim 2, wherein: The reaction temperature in step (1) is 0-40°C; The molar ratio of 2-(2-pyridyl)benzimidazole to dihalogenated linear alkane in step (1) is 1:(1.0-1.5).

4. The preparation method according to claim 2, wherein: The reaction temperature in step (2) is 100-120°C; The molar ratio of the halogenated alkyl-2-(2-pyridyl)benzimidazole to 3,6-di-tert-butylcarbazole in step (2) is 1:(1.0-1.5).

5. The preparation method according to claim 2, wherein: The reaction in step (1) and step (2) is carried out in the presence of a strong base; The strong base is at least one of sodium hydride, potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium phosphate, cesium fluoride, cesium carbonate, sodium acetate, and sodium ethoxide.

6. The preparation method according to claim 5, characterized in that: The molar ratio of 2-(2-pyridyl)benzimidazole to the strong base in step (1) is 1:(10.0-15.0); The molar ratio of the haloalkyl-2-(2-pyridyl)benzimidazole to the strong base in step (2) is 1:(0.3-0.6).

7. The preparation method according to claim 2, wherein: The reaction temperature in step (3) is 120-130°C; The molar ratio of 4-(2-pyridyl)-benzaldehyde to iridium trichloride in step (3) is (1-2.5):

1.

8. The preparation method according to claim 2, wherein: The reaction temperature in step (4) is 100-120°C; The molar ratio of 2-(2-pyridyl)benzimidazole modified with 3,6-di-tert-butylcarbazole linear alkyl, iridium chloride-bridged dimer containing 4-(2-pyridyl)-benzaldehyde ligand, and KPF6 in step (4) is 1:(2.0-2.5):(2.0-4.0).

9. Use of the alkyl chain-modified metal organic iridium complex according to claim 1 or the alkyl chain-modified metal organic iridium complex obtained by the preparation method according to any one of claims 2 to 8 as an aggregation-induced emission material.

10. Use of the aggregation-induced emission material according to claim 9 in organic light-emitting diode devices and optical films.

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