A diacetylacetone coordinated iridium compound, preparation method and application thereof

Abstract

The invention discloses a diacetylacetone coordinated iridium compound, a preparation method and an application thereof, and preliminarily evaluates the catalytic effect thereof in a visible light catalytic reaction. Specifically, under an inert gas, Na[Ir(acac)2Cl2] and 2,2'-bipyridine (bpy) react in ethylene glycol for a period of time, cool to room temperature, and continue to add KPF6 to obtain a yellow solid target product Ir(bpy)(acac)2PF6. The target product is obtained by a diffusion method to obtain a single crystal of the target compound. Compared with the prior art, the invention prepares an iridium compound with a completely new structure; and catalyzes the trifluoroacetylation reaction of phenylpropiolate, showing excellent reaction activity, high conversion rate, and good application prospects.

Description

Technical Field

[0001] The invention relates to a diacetylacetone coordinated iridium compound, a preparation method and an application thereof, and in particular to a compound [Ir(bpy)(acac)2]PF6 in which two acetylacetones and one 2,2'-bipyridine are simultaneously coordinated to an iridium atom, and a preparation method thereof, as well as a compound exhibiting unique catalytic activity in a visible light catalytic reaction, and belongs to the field of chemical industry. Background Art

[0002] In recent years, visible light catalysis has become a very important application in organic chemical reactions as a new and efficient organic synthesis method. Iridium compound photocatalysts have a stable structure, strong absorption in the visible light region, and the advantage of a long redox potential and fluorescence lifetime. They are currently widely used in the research of various visible light catalytic organic reactions and are one of the most important photosensitizers.

[0003] Iridium complexes have high luminescence quantum efficiency, and the absorption and emission spectra can be effectively regulated by modifying different ligands. Its fluorescence lifetime is longer than that of other metal complexes, allowing the excited state to exist for a longer time. At the same time, the luminescence color can cover the entire luminescence area by modifying the structure of different ligands, so iridium complexes are currently widely used as photocatalysts for organic synthesis.

[0004] Up to now, the synthesis method of iridium photosensitizer mainly uses hydrated iridium trichloride as raw material, which reacts with cyclometal ligands to obtain iridium chloride bridge dimer. Then, using iridium chloride bridge dimer as the starting material, iridium photosensitizer is synthesized through two routes respectively. Route one is to dissolve the iridium chloride bridge dimer and N^N ligand in ethylene glycol, reflux for 15 hours, and then add anions to obtain iridium photosensitizer with a yield of 75% to 85%. The synthesis method of route two is relatively mild. The iridium chloride bridge dimer and N^N ligand are dissolved in dichloromethane and methanol, reflux for 5 hours, cooled to room temperature, and anions are added for 3 hours to obtain iridium photosensitizer with a yield of 70% to 80%. The synthesis route is as follows Figure 1 .

[0005] Therefore, finding simple synthesis methods, new structures, and excellent catalytic activity is an important direction for the development of iridium photosensitizers as photocatalysts. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a method for preparing a diacetylacetone coordinated iridium compound with a new structure and high catalytic activity and its application. The compound has excellent reaction activity and high conversion rate in the trifluoroacetylation reaction of phenylpropiolate.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The molecular structure of the diacetylacetone coordinated iridium compound of the present invention is as follows:

[0009]

[0010] The preparation route is as follows:

[0011]

[0012] The preparation method of the invention comprises the following steps: using Na[Ir(acac)2Cl2], 2,2'-bipyridine (bpy) and KPF6 as raw materials to synthesize a diacetylacetone coordinated iridium compound under ethylene glycol conditions.

[0013] The specific steps are: under inert gas, Na[Ir(acac)2Cl2] and 2,2'-bipyridine (bpy) react in ethylene glycol for a period of time, cool to room temperature, and continue to add KPF6 to obtain the target compound.

[0014] The diacetylacetone coordinated iridium compound is used as a photocatalyst in the trifluoroacetylation reaction of phenylpropiolate.

[0015] Beneficial effects of the present invention:

[0016] The diacetylacetone coordinated iridium compound photocatalyst of the present invention improves its catalytic activity and conversion rate. In the context of the industrial application of contemporary photocatalytic reactions and their reliance on efficient iridium catalysts, it is of great significance whether to improve the original catalyst or to invent an iridium compound with a completely new structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the product of the invention and constitute a part of the specification. Together with the following specific examples, they are used to explain the invention but do not constitute a limitation of the invention. In the accompanying drawings:

[0018] Figure 1 :The literature reports the synthesis route of iridium photosensitizer.

[0019] Figure 2 : Hydrogen spectrum of [Ir(bpy)(acac)2]PF6 prepared by the present invention.

[0020] Figure 3 : Carbon spectrum of [Ir(bpy)(acac)2]PF6 prepared by the present invention.

[0021] Figure 4 : Mass spectrum of [Ir(bpy)(acac)2]PF6 prepared by the present invention.

[0022] Figure 5: The crystal molecular structure of [Ir(bpy)(acac)2]PF6 prepared by the present invention. DETAILED DESCRIPTION

[0023] The specific implementation cases of the present invention are described in detail below. It should be understood that the specific implementation cases described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0024] The points and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0025] In the following examples, the raw material Na[Ir(acac)2Cl2] source was prepared by the method disclosed in the literature “The influence of sodium and barium ions on the structures of iridium(III)acetylacetonate complexes” (Res Chem Intermed, 2015, 41:7631-7640, DOI 10.1007 / s11164-014-1848-6).

[0026] Embodiment 1:

[0027] Under inert gas, add 1g (2.1mmol) Na[Ir(acac)2Cl2] and 2.18g (14mmol) 2,2'-bipyridine (bpy) to the reaction bottle, then add 50mL ethylene glycol, and react at 150℃ for 18h. Cool to room temperature, add 6.32g (34.4mmol) KPF6, continue stirring and react for 2h, filter, rinse the filter cake with methanol, and vacuum dry for 6h to obtain 1.32g of yellow solid Ir(bpy)(acac)2PF6 with a yield of 92.3%.

[0028] Embodiment 2:

[0029] Under inert gas, add 5g (10.5mmol) Na[Ir(acac)2Cl2] and 10.9g (70mmol) 2,2'-bipyridine (bpy) to the reaction bottle, then add 250mL ethylene glycol, and react at 150℃ for 24h. Cool to room temperature, add 31.6g (172mmol) KPF6, continue stirring and react for 4h, filter, rinse the filter cake with methanol, and vacuum dry for 6h to obtain 6.75g of yellow solid Ir(bpy)(acac)2PF6 with a yield of 94.4%.

[0030] Structural analysis of [Ir(bpy)(acac)2]PF6 of the present invention:

[0031] (1) Elemental analysis, theoretical value (%): C 34.73, H 3.21; measured value (%): C 34.72, H 3.18. The measured value is consistent with the theoretical value.

[0032] (2) Hydrogen spectrum 1 H NMR, 500 MHz, DMSO-d6, as Figure 2 As shown), chemical shift (ppm): 8.81 (d, J = 8.1 Hz, 2H), 8.48 (dd, J = 5.7, 1.5 Hz, 2H), 8.31 (td, J = 7.9, 1.5 Hz, 2H), 7.82 (ddd, J = 7.4, 5.7, 1.3 Hz, 2H), 5.73 (s, 2H), 2.15 (s, 6H), 1.77 (s, 6H).

[0033] (3) Carbon spectrum 13 C NMR, 500 MHz, DMSO-d6, as Figure 3 As shown), chemical shift (ppm): 187.37, 186.41, 158.41, 151.11, 141.30, 128.07, 124.71, 102.12, 26.71, 25.87.

[0034] (4) Mass spectrometry (ESI-MS, such as Figure 4 As shown in the figure, there is a molecular ion peak of 547, which is [Ir(bpy)(acac)2] + The molecular weight of the product was consistent with that of the target product.

[0035] (5) Crystal structure (such as Figure 5 As shown in the figure, it can be seen that the measured molecular structure is completely consistent with the theory.

[0036] The results of elemental analysis, hydrogen spectrum, carbon spectrum, mass spectrum, infrared spectrum and crystal structure showed that the sample was consistent with the target [Ir(bpy)(acac)2]PF6.

[0037] Evaluation of the photocatalytic performance of [Ir(bpy)(acac)2]PF6 of the present invention:

[0038] Take a reaction tube, add phenyl propiolate 0.2mmol, trifluoromethyl reagent 0.4mmol, [Ir(bpy)(acac)2]PF6 photocatalyst 0.002mmol, alkaline reagent K2HPO4 0.4mmol, total solvent 2mL, solvent is N,N-dimethylformamide and n-hexane mixed solvent volume ratio 1:1, sealed at 70℃ stirring reaction, shielded from light, irradiated with blue LED bulb, reaction for 12h. Cool to room temperature, add 6mL distilled water, extract with ethyl acetate, combine the extracts, remove the solvent, and separate the product by silica gel column chromatography.

[0039] The results of the trifluoroacetylation reaction of phenylpropiolate catalyzed by blue light are shown in Table 1.

[0040] Table 1 Trifluoroacetylation of phenylpropiolate catalyzed by [Ir(bpy)(acac)2]PF6 under blue light irradiation

[0041]

[0042] [Ir(bpy)(acac)2]PF6 as a photocatalyst has catalytic activity for the trifluoroacetylation reaction of phenylpropiolate in the presence of a mixture of N,N-dimethylformamide and n-hexane as a solvent, and the overall yield can be maintained at more than 60%. Therefore, the iridium compound of the present invention has a certain guiding significance for the photocatalytic trifluoroacetylation reaction of phenylpropiolate.

[0043] In summary, the present invention provides a new structure and preparation method, which is simple to operate, simple to purify, has few steps and high yield. At the same time, the prepared [Ir(bpy)(acac)2]PF6 performs photocatalysis on the trifluoroacetylation reaction of phenylpropiolate, showing good catalytic performance.

[0044] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A diacetylacetone coordinated iridium compound, characterized in that: The compound is [Ir(bpy)(acac)2]PF6, and its structure is:

2. A method for preparing a diacetylacetone coordinated iridium compound as claimed in claim 1, characterized in that: A diacetylacetone coordinated iridium compound was synthesized using Na[Ir(acac)2Cl2] and 2,2'-bipyridine as raw materials under ethylene glycol conditions. The preparation route is: The specific steps are: under inert gas, Na[Ir(acac)2Cl2] and 2,2'-bipyridine react in ethylene glycol for a period of time, cool to room temperature, continue to add KPF6 to react, filter and dry to obtain the target compound.

3. The preparation method according to claim 2, characterized in that: The molar ratio of Na[Ir(acac)2Cl2]:2,2'-bipyridine:KPF6 is 1:6.6:16.

4.

4. The preparation method according to claim 2, characterized in that: The amount of ethylene glycol added is 50 times the mass of the raw material Na[Ir(acac)2Cl2].

5. The preparation method according to claim 2, characterized in that: The reaction is carried out at 150° C. for 15 to 24 hours.

6. The preparation method according to claim 2, characterized in that: Continue to add KPF6 and stir the reaction for 2 to 5 hours.

7. The preparation method according to claim 2, characterized in that: The filter cake was filtered and rinsed with methanol, and then dried in vacuum for more than 6 hours to obtain yellow solid Ir(bpy)(acac)2PF6.

8. Use of the bis(acetylacetone) coordinated iridium compound as claimed in claim 1 as a photocatalyst in the trifluoroacetylation reaction of phenylpropiolate.

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