CN111253443B

CN111253443B - Preparation method and application of electroblotting group modified cyclometalated iridium complex

Info

Publication number: CN111253443B
Application number: CN202010215400.XA
Authority: CN
Inventors: 刘春�; 王磊
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2020-03-25
Filing date: 2020-03-25
Publication date: 2021-10-15
Anticipated expiration: 2040-03-25
Also published as: CN111253443A

Abstract

A preparation method and application of a cyclometalated iridium complex modified by an electroabsorption group belong to the technical field of luminescent materials. The invention synthesizes three cyclometalated iridium complexes by taking substituted pyridine as a cyclometalated ligand and 1, 10-phenanthroline as an auxiliary ligand, and the three cyclometalated iridium complexes are immobilized on an ethyl cellulose membrane to prepare an oxygen sensitive probe with high oxygen sensitivity, thereby realizing the on-line detection of oxygen concentration. The iridium complex synthesized by the method has good light stability, and the oxygen sensing film prepared by the iridium complex has the advantages of simple preparation, reliable work and the like, and has good application prospect.

Description

Preparation method and application of electroblotting group modified cyclometalated iridium complex

Technical Field

The invention relates to a preparation method and application of a cyclometalated iridium complex modified by an electroabsorption group, belonging to the technical field of luminescent materials.

Background

The detection of molecular oxygen is of great significance and is widely applied to the fields of chemistry, clinical analysis, environmental monitoring, oceanography, life science and the like (Chem. Soc. Rev., 2013, 42, 8700-8732). The optical Oxygen sensor is based on the quenching of molecular Oxygen to the fluorescence or phosphorescence of Oxygen-sensitive probes (OSPs) ((Chem. Soc. Rev., 2014, 43, 3666-3761) has the advantages of quick response, good operation stability, no oxygen consumption and complete reversibility.

The luminescence Oxygen sensing technology utilizes the principle that Oxygen molecules quench phosphorescence (or delayed fluorescence) of Oxygen-sensitive probes (OSPs) to realize the detection of Oxygen concentration. The OSPs in the first triplet excited state (T1 state) undergo dynamic collisions with the ground state oxygen molecules, the T1 state energy of the OSPs is transferred to the oxygen molecules by collisions, the phosphorescence (or delayed fluorescence) of the OSPs is quenched, and the collision process is accompanied by the generation of singlet oxygen molecules. The luminescence oxygen sensor has the advantages of no oxygen consumption in the detection process, good precision, high accuracy, capability of realizing remote oxygen concentration detection, easiness in miniaturization and the like, and is widely concerned by people.

The cyclometalated iridium complex has relatively long luminescence life, higher quantum yield and can flexibly adjust the photophysical and electrochemical properties thereof through the change of a ligand structure, and is particularly suitable for being used as an oxygen sensitive probe (Dalton Trans.,2016, 45, 734-741; J. Mater. Chem. C,2017, 5, 3519-3527; Dyes Pigm., 2017, 136, 641-647.)。

Fluorine is a very special element, different from other halogens, and fluorine atoms have the strongest electronegativity and atomic radius close to that of hydrogen atoms due to unique electronic structures, so that the fluorine atoms can replace the hydrogen atoms more conveniently to perform structural modification on parent molecules, and further effectively adjust the performance of the compound.

The fluoro, trifluoromethyl and cyano substituted cyclometalated iridium complex designed by the invention can be used as a luminescent material to be applied to an oxygen sensitive probe of an oxygen sensor, and an oxygen sensing film prepared by the fluoro, trifluoromethyl and cyano substituted cyclometalated iridium complex has the advantages of rapidness, reliability in operation and the like.

Disclosure of Invention

The invention aims to provide a preparation method and application of a cyclometalated iridium complex modified by an electroabsorption group.

The technical scheme adopted by the invention is as follows: a fluorocyclo-metallic iridium complex Ir1 is prepared from 4-triphenylamine boric acid and 2-bromo-6-fluoropyridine through synthesizing C^-The N-type ring metal ligand is combined with 1, 10-phenanthroline to complex iridium metal ions, and finally the iridium metal ions are synthesized by replacing anions, and the structure of the compound iridium metal ligand is as follows:

the preparation method of the fluoro-cyclic metal ligand and iridium complex Ir1 comprises the following specific synthetic steps:

（1）C^{^}synthesis of N-type ring metal ligand 2- (4-diphenylamino) phenyl-6-fluoropyridine: adding 1.0 mmol of 2-bromo-6-fluoropyridine, 1.5 equiv boric acid, potassium carbonate and palladium acetate into a round bottom flask in turn in the air, then adding 8 mL of ethanol-water mixed solution with the volume ratio of 3:1, magnetically stirring at 80 ℃ to carry out Suzuki cross-coupling reaction, tracking the reaction process by thin-layer chromatography, adding 20 mL of saturated saline after the reaction is completed, extracting the reaction product by dichloromethane, combining organic phases, concentrating under reduced pressure, and separating by column chromatography to obtain C^{^}An N-type ring metal ligand.

(2) Synthesis of iridium complex Ir 1: IrCl was added to a round bottom flask₃·3H₂O and 2.5 equivalents of C^{^}N-type ring metal ligand in the mixture of 3:1 (by volume) glycol monoethyl ether and water₂Magnetically stirring and reacting at 120 ℃ for 24 hours under protection, and concentrating the reaction solution under reduced pressure after the reaction is finished to obtain a dichloro-bridge intermediate product. Adding the dichloro bridge intermediate product and 3.0 equivalent of 1, 10-phenanthroline into a round-bottom flask, and heating and refluxing for 24 hours at 120 ℃ in a nitrogen atmosphere by using anhydrous ethylene glycol monoethyl ether as a solvent. After the reaction was complete, the reaction mixture was cooled to room temperature and then 20 mL of KPF was added₆The saturated aqueous solution was stirred at room temperature for 3 h. Separating the separated precipitate with dichloromethane/petroleum ether as eluent by column chromatography, and purifying to obtain target product Ir1 with a product structure¹H NMR、¹³C NMR and mass spectrum confirmation.

The fluorinated cyclometalated iridium complex is used as an oxygen sensitive probe.

A cyano-modified cyclometalated iridium complex Ir2 is prepared from 4-triphenylamine boric acid and 2-bromo-5-cyanopyridine through synthesizing C^-The N-type ring metal ligand is combined with 1, 10-phenanthroline to complex iridium metal ions, and finally the iridium metal ions are synthesized by replacing anions, and the structure of the compound iridium metal ligand is as follows:

the preparation method of the cyano-modified cyclometalated ligand and iridium complex Ir2 comprises the following specific synthetic steps:

（3）C^{^}synthesis of N-type ring metal ligand 2- (4-diphenylamino) phenyl-5-cyanopyridine: adding 1.0 mmol of 2-bromo-5-cyanopyridine, 1.5 equiv boric acid (1.5 equiv.), potassium carbonate (2.0 equiv.), palladium acetate (1.5% equiv.) into a round-bottom flask in turn in the air, then adding 8 mL of ethanol-water mixed solution with the volume ratio of 3:1, carrying out Suzuki cross-coupling reaction by magnetic stirring at 80 ℃, tracking the reaction process by thin-layer chromatography, adding 20 mL of saturated saline solution after the reaction is completed, extracting the reaction product by dichloromethane for 3 times by 20 mL, combining organic phases, carrying out reduced pressure concentration, and carrying out column chromatography separation to obtain C^{^}An N-type ring metal ligand.

(4) Synthesis of iridium complex Ir 2: IrCl was added to a round bottom flask₃·3H₂O and 2.5 equivalents of C^{^}N-type ring metal ligand in the mixture of 3:1 (by volume) glycol monoethyl ether and water₂Under the protection condition, magnetically stirring the mixture at 120 ℃ for reaction for 24 hours, and after the reaction is finished, decompressing and concentrating the reaction solution to obtain a dichloro-bridge intermediate product. Adding the dichloro bridge intermediate product and 3.0 equivalent of 1, 10-phenanthroline into a round-bottom flask, and heating and refluxing for 24 hours at 120 ℃ in a nitrogen atmosphere by using anhydrous ethylene glycol monoethyl ether as a solvent. After the reaction was complete, the reaction mixture was cooled to room temperature and then 20 mL of KPF was added₆The saturated aqueous solution was stirred at room temperature for 3 h. Separating the separated precipitate with dichloromethane/petroleum ether as eluent by column chromatography, and purifying to obtain target product Ir2 with a product structure¹H NMR、¹³C NMR and mass spectrum confirmation.

The cyano-modified cyclometalated iridium complex is used as an oxygen sensitive probe OSPs.

A trifluoromethyl-modified cyclometalated iridium complex Ir3 is prepared through synthesizing intermediate from 4-bromobenzeneboronic acid and 2-bromo-5-trifluoromethylpyridine, and synthesizing C from intermediate and 4-triphenylamineboronic acid^-The N-type ring metal ligand and 1, 10-phenanthroline togetherComplexing iridium metal ions, and finally synthesizing by replacing anions, wherein the structure of the complex is as follows:

the preparation method of the trifluoromethyl modified cyclometalated ligand and iridium complex Ir3 comprises the following specific synthetic steps:

（5）C

synthesis of N-type ring metal ligand intermediate 2- (4-bromophenyl) -5-trifluoromethylpyridine: under the air condition, 1.0 mmol of 2-bromo-5-trifluoromethylpyridine, 1.5 equiv of 4-bromobenzeneboronic acid, potassium carbonate and palladium acetate are sequentially added into a round-bottom flask, 8 mL of ethanol-water mixed solution with the volume ratio of 3:1 is added, the mixture is magnetically stirred at 80 ℃ for Suzuki cross-coupling reaction, the reaction process is tracked by thin-layer chromatography, 20 mL of saturated saline and 20 mL of dichloromethane are added after the reaction is completed, reaction products are extracted for 3 times, organic phases are combined, the organic phases are decompressed and concentrated, and the C is prepared by column chromatography separation^{^}An N-type ring metal ligand intermediate.

（6）C

Synthesis of N-type ring metal ligand 2- (4- (4-diphenylamino) phenyl-5-trifluoromethylpyridine: under the air condition, sequentially adding 1.0 mmol of a ring metal ligand intermediate, 4-triphenylamine boric acid (1.5 equiv.), potassium carbonate (2.0 equiv.), palladium acetate (1.5% equiv.) into a round bottom flask, then adding 8 mL of ethanol-water mixed solution with the volume ratio of 3:1, magnetically stirring at 80 ℃ to carry out Suzuki cross-coupling reaction, tracking the reaction process by thin-layer chromatography, after the reaction is completed, adding 20 mL of saturated saline solution, extracting the reaction product by 20 mL of dichloromethane for 3 times, combining organic phases, concentrating under reduced pressure, and carrying out column chromatography separation to obtain C^{^}An N-type ring metal ligand.

(7) Synthesis of iridium complex Ir 3: IrCl was added to a round bottom flask₃·3H₂O and 2.5 equivalents of C^{^}N-type ring metal ligand in the mixture of 3:1 (by volume) glycol monoethyl ether and water₂Under the protection condition, magnetically stirring the mixture at 120 ℃ for reaction for 24 hours, and after the reaction is finished, decompressing and concentrating the reaction solution to obtain a dichloro-bridge intermediate product. Adding the dichloro bridge intermediate product and 3.0 equivalent of 1, 10-phenanthroline into a round-bottom flask, and heating and refluxing for 24 hours at 120 ℃ in a nitrogen atmosphere by using anhydrous ethylene glycol monoethyl ether as a solvent. After the reaction was complete, the reaction mixture was cooled to room temperature and then 20 mL of KPF was added₆The saturated aqueous solution was stirred at room temperature for 3 h. Separating the separated precipitate with dichloromethane/petroleum ether as eluent by column chromatography, and purifying to obtain target product Ir3 with a product structure¹H NMR、¹³C NMR and mass spectrum confirmation.

The trifluoromethyl modified cyclometalated iridium complex is used as an oxygen sensitive probe OSPs.

Synthesis of ring metal ligands in compound Ir3 starting from: the halogenated nitrogen heteroaromatic ring compound is selected from 2-bromo-5-trifluoromethyl pyridine, and the aryl boric acid is selected from 4-bromobenzeneboronic acid and 4-triphenylamineboronic acid;

the invention has the beneficial effects that: the iridium complex Ir1 is easy to prepare, diphenylamino is introduced into the 4-position of the benzene ring of 2-phenylpyridine, and fluorine atoms are introduced into the 6-position of the pyridine ring, so that the iridium complex with high oxygen sensitivity can be obtained. Quenching ratio of oxygen sensing film prepared therefromI ₀ /I ₁₀₀A quenching constant of 35 and 0.073 Torr was obtained^-1The oxygen sensing membrane has good operation stability. Cyano-modified cyclometalated iridium complex Ir2, and quenching ratio of oxygen sensing film prepared from sameI ₀ /I ₁₀₀A quenching constant of 28, 0.058 Torr^-1And the oxygen sensing film has good operation stability. Cyclometalated iridium complex Ir3, quenching ratio of oxygen sensing film prepared therefromI ₀ /I ₁₀₀At 37, the quenching constant reached 0.092 Torr^-1The oxygen sensing film has good light stability, simple preparation and reliable work. The compounds Ir1, Ir2 and Ir3 synthesized by the method have wide application prospects in the fields of organic electroluminescent materials, oxygen-sensitive materials and the like.

Drawings

FIG. 1 is a diagram showing an ultraviolet-visible absorption spectrum of a complex Ir1 solution (solvent is CH)₂Cl₂，10^-5mol/L)。

FIG. 2 is a diagram of the emission spectrum of complex Ir1 in solution (solvent is CH)₂Cl₂，10^-5 mol/L)。

FIG. 3 is a graph of the emission spectrum of complex Ir1 on an Ethyl Cellulose (EC) film.

FIG. 4 is a diagram showing a UV-VIS absorption spectrum of a complex Ir2 solution (solvent is CH)₂Cl₂，10^-5mol/L)。

FIG. 5 is a diagram of the emission spectrum of complex Ir2 in solution (solvent is CH)₂Cl₂，10^-5 mol/L)。

FIG. 6 is a graph of the emission spectrum of complex Ir2 on an Ethyl Cellulose (EC) film.

FIG. 7 is a chart of the UV-VIS absorption spectrum of a complex Ir3 solution (solvent is CH)₂Cl₂，10^-5mol/L)。

FIG. 8 is a chart of the emission spectrum of complex Ir3 in solution (solvent is CH)₂Cl₂，10^-5 mol/L)。

FIG. 9 is a graph of the emission spectrum of complex Ir3 on an Ethyl Cellulose (EC) film.

FIG. 10 is a dynamic phosphorescence response curve (support material: EC) for a complex Ir1 oxygen sensing film.

FIG. 11 is a graph of the operating stability test curve (support material: EC) for a complex Ir1 oxygen sensing film.

FIG. 12 is a dynamic phosphorescence response curve (support material: EC) for a complex Ir2 oxygen sensing film.

FIG. 13 is a reversibility test curve (support material: EC) of a complex Ir2 oxygen sensing film.

FIG. 14 is a dynamic phosphorescence response curve (support material: EC) for a complex Ir3 oxygen sensing film.

FIG. 15 is an operating stability test curve (support material: EC) for a complex Ir3 oxygen sensing film.

Detailed Description

EXAMPLE 1 Synthesis of Compound Ir1

(1) Synthesis of Ring Metal ligand 2- (4-Diphenylamino) phenyl-6-fluoropyridine: adding 1.0 mmol of 2-bromo-6-fluoropyridine, 1.5 equiv boric acid, potassium carbonate and palladium acetate into a round bottom flask in turn in the air, then adding 8 mL of ethanol-water mixed solution with the volume ratio of 3:1, magnetically stirring at 80 ℃ to carry out Suzuki cross-coupling reaction, tracking the reaction process by thin-layer chromatography, adding 20 mL of saturated saline after the reaction is completed, extracting the reaction product by dichloromethane, combining organic phases, concentrating under reduced pressure, and separating by column chromatography to obtain C^{^}N-type ring metal ligand, yield 85%.

(2) And (3) synthesis of an iridium complex: IrCl was added to a round bottom flask₃·3H₂O and 2.5 equivalents of C^{^}N-type ring metal ligand in the mixed solution of glycol monoethyl ether and water with the volume ratio of 3:1 for removing oxygen respectively₂Under the protection condition, magnetically stirring the mixture at 120 ℃ for reaction for 24 hours, and after the reaction is finished, decompressing and concentrating the reaction solution to obtain a dichloro-bridge intermediate product. Adding the dichloro bridge intermediate product and 3.0 equivalent of 1, 10-phenanthroline into a round-bottom flask, and heating and refluxing for 24 hours at 120 ℃ in a nitrogen atmosphere by using anhydrous ethylene glycol monoethyl ether as a solvent. After the reaction was complete, the reaction mixture was cooled to room temperature and then 20 mL of KPF was added₆The saturated aqueous solution was stirred at room temperature for 3 h. Extracting the reaction solution, concentrating under reduced pressure to obtain crude product, separating by column chromatography with dichloromethane/petroleum ether as eluent, and purifying to obtain target product with yield of 68%, wherein the product structure is obtained by¹H NMR、¹³C NMR and mass spectrum confirmation.

EXAMPLE 2 Synthesis of the Compound Ir2

(1) Synthesis of Cyclometalated ligand 2- (4-diphenylamino) phenyl-5-cyanopyridine: adding 1.0 mmol of 2-bromo-5-cyanopyridine, 1.5 equiv of 4-triphenylamine boric acid, 2.0 equiv of potassium carbonate and 1.5 percent equiv of palladium acetate into a round bottom flask in turn in air, then adding 8 mL of ethanol-water mixed solution with the volume ratio of 3:1, carrying out Suzuki cross-coupling reaction by magnetic stirring at 80 ℃, tracking the reaction progress by thin layer chromatography, and adding saturated solution after the reaction is completedExtracting the reaction product with 20 mL of saline solution by dichloromethane for 3 times with 20 mL of the solution, combining organic phases, concentrating under reduced pressure, and separating by column chromatography to obtain C^{^}N-type ring metal ligand, yield 70%.

(2) And (3) synthesis of an iridium complex: IrCl was added to a round bottom flask₃·3H₂O and 2.5 equivalents of C^{^}N-type ring metal ligand in the mixed solution of glycol monoethyl ether and water with the volume ratio of 3:1 for removing oxygen respectively₂Under the protection condition, magnetically stirring the mixture at 120 ℃ for reaction for 24 hours, and after the reaction is finished, decompressing and concentrating the reaction solution to obtain a dichloro-bridge intermediate product. Adding the dichloro bridge intermediate product and 3.0 equivalent of 1, 10-phenanthroline into a round-bottom flask, and heating and refluxing for 24 hours at 120 ℃ in a nitrogen atmosphere by using anhydrous ethylene glycol monoethyl ether as a solvent. After the reaction was complete, the reaction mixture was cooled to room temperature and then 20 mL of KPF was added₆The saturated aqueous solution was stirred at room temperature for 3 h. Extracting the reaction solution, concentrating under reduced pressure to obtain crude product, separating by column chromatography with dichloromethane/petroleum ether as eluent, and purifying to obtain target product with yield of 27%, wherein the product structure is determined by¹H NMR、¹³C NMR and mass spectrum confirmation.

EXAMPLE 3 Synthesis of Compound Ir3

(1) Synthesis of ligand intermediate 2- (4-bromophenyl) -5-trifluoromethylpyridine: adding 1.0 mmol of 2-bromo-5-trifluoromethylpyridine, 1.5 equiv of 4-bromobenzeneboronic acid, potassium carbonate and palladium acetate into a round bottom flask in turn in the air, then adding 8 mL of ethanol-water mixed solution with the volume ratio of 3:1, magnetically stirring at 80 ℃ to carry out Suzuki cross-coupling reaction, tracking the reaction process by thin-layer chromatography, after the reaction is completed, adding 20 mL of saturated saline, extracting the reaction product by 20 mL of dichloromethane for 3 times, combining organic phases, concentrating under reduced pressure, and separating by column chromatography to obtain C^{^}An N-type ring metal ligand intermediate.

(2) Synthesis of Cyclometalated ligand 2- (4- (4-diphenylamino) phenyl-5-trifluoromethylpyridine: in the air, 1.0 mmol of the intermediate of the ring metal ligand, 4-triphenylamine boric acid (1.5 equiv.), potassium carbonate (2.0 equiv.), palladium acetate (1.5% equiv.) were sequentially added into a round-bottom flask, and then the volume ratio was 3:1Performing Suzuki cross-coupling reaction by magnetic stirring at 80 deg.C with ethanol-water mixed solution 8 mL, tracking reaction process by thin layer chromatography, adding saturated saline solution 20 mL after reaction, extracting reaction product with 20 mL dichloromethane for 3 times, mixing organic phases, concentrating under reduced pressure, and separating by column chromatography to obtain C^{^}N-type ring metal ligand, yield 80%.

(3) And (3) synthesis of an iridium complex: IrCl was added to a round bottom flask₃·3H₂O and 2.5 equivalents of C^{^}N-type ring metal ligand in the mixed solution of glycol monoethyl ether and water with the volume ratio of 3:1 for removing oxygen respectively₂Under the protection condition, magnetically stirring at 120 ℃, reacting for 24 hours, and after the reaction is finished, concentrating the reaction solution under reduced pressure to obtain a dichloro-bridge intermediate product. Adding the dichloro bridge intermediate product and 3.0 equivalent of 1, 10-phenanthroline into a round-bottom flask, and heating and refluxing for 24 hours at 120 ℃ in a nitrogen atmosphere by using anhydrous ethylene glycol monoethyl ether as a solvent. After the reaction was complete, the reaction mixture was cooled to room temperature and then 20 mL of KPF was added₆The saturated aqueous solution was stirred at room temperature for 3 h. Extracting the reaction solution, concentrating under reduced pressure to obtain crude product, separating by column chromatography with dichloromethane/petroleum ether as eluent, and purifying to obtain target product with yield of 73%, wherein the product structure is obtained by¹H NMR、¹³C NMR and mass spectrum confirmation.

Example 4 spectral Properties of the complexes Ir1, Ir2 and Ir3

FIG. 1 shows the complex Ir1 at a concentration of 10^-5The ultraviolet/visible absorption spectrum obtained by mol/L has absorption wavelengths of 229 nm (4.42), 269 nm (4.39), 398 nm (2.52) and 433 nm (3.04). FIG. 2 shows the reaction of complex Ir1 in organic solvent CH₂Cl₂A spectrum of emission spectra of whereinλ _max= 554 nm; FIG. 3 is a graph of the emission spectrum of complex Ir1 on an Ethylcellulose (EC) film, whereinλ _max= 545 nm。

FIG. 4 shows the complex Ir2 at a concentration of 10^-5The ultraviolet/visible absorption spectrum obtained by mol/L has the absorption wavelengths of 231 nm (4.59), 270 nm (4.84), 374 nm (2.07) and 449 nm (3.78). FIG. 5 shows the reaction of complex Ir2 in organic solvent CH₂Cl₂A spectrum of emission spectra of whereinλ _max= 597 nm; FIG. 6 is a graph of the emission spectrum of complex Ir2 on an Ethylcellulose (EC) film, whereinλ _max= 584 nm。

FIG. 7 shows the complex Ir3 at a concentration of 10^-5The absorption wavelengths of the obtained ultraviolet/visible absorption spectrums of mol/L are 231 nm (5.49), 237 nm (5.64), 300 nm (6.35) and 522 nm (4.11). FIG. 8 shows the reaction of complex Ir3 in organic solvent CH₂Cl₂A spectrum of emission spectra of whereinλ _max= 600 nm; FIG. 9 is a graph of the emission spectrum of complex Ir3 on an Ethyl Cellulose (EC) film, whereλ _max= 580 nm。

Example 7 oxygen sensing applications of the complexes Ir1, Ir2 and Ir3

An oxygen sensing EC film (the loading amount of the complex Ir1 is 0.5 wt%) is prepared by a solvent volatilization method. Putting an oxygen sensing film into an oxygen sensing flow cell, and introducing O with different volume ratios into the oxygen sensing flow cell₂/N₂Mixed gas, the emission spectrum of complex Ir1 supported on an EC film was tested. FIG. 10 is a graph of the dynamic phosphorescence response of the complex Ir1 oxygen sensing film, and the results show that the oxygen sensing film prepared from the complex Ir1 has high oxygen sensitivity and quenching ratioI ₀ /I ₁₀₀At 35, the oxygen concentration can be monitored on-line over a range of 0-100% oxygen concentration by volume. FIG. 11 is a graph of the operating stability test of a complex Ir1 oxygen sensing film, with complete quenching of phosphorescence from 100% nitrogen to 100% oxygen only requiring 6.0 s; from 100% oxygen to 100% nitrogen, 15.0 s is needed for phosphorescence recovery, and the complex Ir1 oxygen sensing film has the advantages of quick response and stable operation.

An oxygen sensing EC film (Ir2 loading 0.5 wt%) was prepared by a solvent evaporation method. The O of the complex Ir2 loaded on the EC film at different volume ratios is tested by a spectrometer₂/N₂Emission spectrum in mixed gas. FIG. 12 is a graph of the dynamic phosphorescence response of the complex Ir2 oxygen sensing film, and the results show that the oxygen sensing film prepared from the complex Ir2 has high oxygen sensitivity and quenching ratioI ₀ / I ₁₀₀The oxygen concentration can be monitored on-line at 28 f, in the range of 0-100% oxygen concentration by volume. FIG. 13 is a reversibility test curve of a complex Ir2 oxygen sensing membrane. From 100% nitrogen to 100% oxygen, phosphorescence is only required to be completely quenched for 6.0 s; from 100% oxygen to 100% nitrogen, phosphorescence recovery required 12.1 s, indicating that the complex Ir2 oxygen sensing film had excellent operational stability.

An oxygen sensing EC film (the loading amount of the complex Ir3 is 0.5 wt%) is prepared by a solvent volatilization method. Putting an oxygen sensing film into an oxygen sensing flow cell, and introducing O with different volume ratios into the oxygen sensing flow cell₂/N₂The emission spectrum of the complex Ir3 supported on the EC film was measured by a spectrometer. FIG. 14 is a graph of the dynamic phosphorescence response of the complex Ir3 oxygen sensing film, and the results show that the oxygen sensing film prepared from the complex Ir3 has high oxygen sensitivity and quenching ratioI ₀ /I ₁₀₀The oxygen concentration can be monitored on-line at 37 in the range of 0-100% oxygen concentration by volume. FIG. 15 is a graph of the operating stability test of a complex Ir3 oxygen sensing film, with complete quenching of phosphorescence from 100% nitrogen to 100% oxygen only requiring 4.0 s; from 100% oxygen to 100% nitrogen, phosphorescence recovery required 15.7 s, indicating that the complex Ir3 oxygen sensing film has fast response and stable operation.

Claims

1. A kind of electroabsorption group modified cyclometalated iridium complex is characterized in that the structure of the complex is as follows:

iridium complex Ir 3C synthesized from 4-triphenylamine boronic acid and 2- (4-bromophenyl) -5-trifluoromethylpyridine^-The N-type ring metal ligand and 1, 10-phenanthroline are jointly complexed with iridium metal ions to form the iridium metal ion complex.

2. The preparation method of the electron-withdrawing group-modified cyclometalated iridium complex according to claim 1, wherein the preparation method comprises the following steps: the synthesis steps of the iridium complex Ir3 are as follows:

(1) synthesis of cyclometalated ligand intermediate: taking 4-bromobenzeneboronic acid and 2-bromo-5-trifluoromethylpyridine as reactants, potassium carbonate as alkali and palladium acetate as a catalyst, carrying out Suzuki cross-coupling reaction under the air condition, tracking the reaction process by thin-layer chromatography, and after the reaction is completed, carrying out column chromatography separation to obtain a target product: 2- (4-bromophenyl) -5-trifluoromethylpyridine;

(2) synthesis of cyclometallated ligand: taking 4-triphenylamine boric acid and 2- (4-bromophenyl) -5-trifluoromethylpyridine as substrates, potassium carbonate as alkali and palladium acetate as a catalyst, carrying out Suzuki cross-coupling reaction under the air condition, tracking the reaction process by thin-layer chromatography, and after the reaction is completed, carrying out column chromatography separation to obtain a target product;

(3) and (3) synthesis of an iridium complex: IrCl was added to a round bottom flask₃·3H₂O and 2.5 equivalents of a cyclometalated ligand in a 3:1 volume ratio of ethylene glycol monoethyl ether/water mixed solution, N₂Under the protection condition, magnetically stirring at 120 ℃ for reaction for 24 hours, and after the reaction is finished, concentrating the reaction solution under reduced pressure to obtain a dichloro bridge intermediate product; adding the dichloro bridge intermediate product and 3.0 equivalent of 1, 10-phenanthroline into a round-bottom flask, and heating and refluxing for 24 hours at 120 ℃ in a nitrogen atmosphere by using anhydrous ethylene glycol monoethyl ether as a solvent; after the reaction was complete, the reaction mixture was cooled to room temperature and then 20 mL of KPF was added₆Stirring the saturated aqueous solution at room temperature for 3 hours; extracting the separated precipitate, and concentrating under reduced pressure to obtain a crude product; using dichloromethane/petroleum ether as eluent, separating by column chromatography, and purifying to obtain the target product.

3. The application of the electron-withdrawing group modified cyclometalated iridium complex as claimed in claim 1, wherein: the iridium complex is used for preparing an oxygen sensing film.