Synthesis of azulene-based organometallic rings and photocatalytic applications

Abstract

The application discloses a synthesis method of an azulene-based organometallic ring and belongs to the technical field of catalyst synthesis. The azulene-based organometallic ring 3 is synthesized through a one-pot method with a binuclear compound 1 and an azulene-based organic ligand 2 as raw materials. The azulene-based organometallic ring is synthesized through coordination site regulation with the azulene-based organic ligand as a starting raw material. Compared with the reported azulene-based organometallic ring, the synthesized azulene-based organometallic ring has obvious advantages, such as mild reaction conditions, short reaction time, high yield, simple operation and high light catalytic efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst synthesis, and in particular to a synthesis method and photocatalytic application of an azulenyl organometallic ring. Background Art

[0002] In 1987, Nobel Prize winner in Chemistry Lehn first clearly proposed the concept of supramolecular chemistry. Since then, the field of supramolecular chemistry has rapidly developed, with structures evolving from simple to complex, organized, specific, and functionalized. Because metals and ligands can spontaneously form coordination bonds with bond energies of approximately 15-25 kcal / mol, and the coordination structures are predictable, coordination-induced self-assembly is an effective approach for constructing supramolecular coordination compounds. Complexes with a semi-sandwich structure possess a certain structural novelty, primarily due to the introduction of a cyclopentadiene group, which offers numerous advantages: directional bonding, improved solubility, and increased coordination sites. Therefore, rational design strategies and coordination site manipulation are crucial for the construction of azulenyl organometallic rings.

[0003] Photocatalysis has attracted widespread attention in synthetic chemistry due to its advantages, including clean, mild reaction conditions, high efficiency, and sustainable use of solar energy. Based on the influence of light absorption and electron transfer on catalytic efficiency, researchers have designed a variety of photocatalytic materials, including organometallic complexes, organic dyes, and inorganic semiconductors. However, to date, there have been few reports on efficient photocatalytic reactions using organometallic rings. Therefore, the realization of photocatalytic reactions using azulenyl organometallic rings is of great significance. Summary of the Invention

[0004] The object of the present invention is to provide a method for synthesizing an azulenyl organometallic ring with photocatalytic activity by regulating coordination sites.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for synthesizing an azulenyl organometallic ring is provided. Using a binuclear compound 1 and an azulenyl organic ligand 2 as raw materials, an azulenyl organometallic ring 3 is synthesized via a one-pot method. The reaction equation is shown below:

[0007]

[0008] The specific steps are as follows:

[0009] Under anhydrous and oxygen-free conditions, dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer was added to a methanol solution, followed by the addition of AgOTf (silver trifluoromethanesulfonate). The mixture was stirred at room temperature for 12 h in the dark. After the reaction, the mixture was centrifuged and the supernatant solution (this process yielded the dinuclear compound 1) was removed. Benzoquinone and an 80 mmol / L methanol solution containing NaOH were then added, and the mixture was stirred at room temperature in the dark for another 12 h. The azulene-based organic ligand 2 was dissolved in DMA (dimethylacetamide) and added to the above reaction solution. The mixture was stirred at room temperature for 24 h in the dark. After the reaction, the mixture was centrifuged and the supernatant solution was removed. The product, a single crystal of the azulene-based organometallic ring 3, was obtained by diffusion.

[0010] Furthermore, the azulenyl organic ligand 2 is any one of the following structural formulas:

[0011] .

[0012] Furthermore, the molar ratio of the dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer and AgOTf is 1:2-1:10, preferably 1:6.

[0013] Furthermore, the molar ratio of the binuclear compound 1 and the azulenyl organic ligand 2 is 1:1 to 1:2, preferably 1:1.

[0014] Another object of the present invention is to provide an application of the azulenyl organometallic ring synthesized by the above method in a photocatalytic reaction, specifically, an application as a catalyst in the photocatalytic reaction of thioanisole.

[0015] Beneficial effects of the present invention:

[0016] Compared with previously reported ones, the organometallic ring synthesized by the present invention has obvious advantages: mild reaction conditions, short reaction time, high yield, simple operation, high photocatalytic efficiency, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 Figure 3 is the single crystal structure of azulenyl organometallic ring 3a.

[0019] Figure 2 Figure 3 is the single crystal structure of the azulenyl organometallic ring 3b.

[0020] Figure 3 Figure 3 is the single crystal structure of the azulenyl organometallic ring 3c.

[0021] Figure 4 This is the H NMR spectrum of the azulenyl organometallic ring 3a.

[0022] Figure 5 The UV absorption spectra of the azulenyl organic ligand 2a and the azulenyl organometallic ring 3a. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0024] Example 1: Preparation of azulenyl organometallic ring 3a

[0025] Under anhydrous and oxygen-free conditions, dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer (0.01 mmol) was added to 1 mL of methanol solution, followed by 0.04 mmol of AgOTf, and the reaction was stirred at room temperature for 12 h in the dark. After the reaction was completed, centrifugation was performed, the supernatant solution was removed, and 0.01 mmol of benzoquinone and 80 mmol / L methanol solution containing NaOH were added, and the mixture was stirred at room temperature in the dark for another 12 h. 0.01 mmol of azulenyl organic ligand 2a was dissolved in 0.5 mL of DMA solution and added to the above mixed solution. The reaction was stirred at room temperature for 24 h in the dark. After the reaction was completed, centrifugation was performed, the supernatant solution was removed, and single crystals of azulenyl organometallic ring 3a were obtained by diffusion method with a yield of 60%. The structural formula is:

[0026]

[0027] 1 H NMR (400 MHz, CD3OD): δ = 8.31-8.25 (m, 12H), 8.16 (m, 4H), 7.73(s, 2H), 7.65 (m, 2H), 7.53 (m, 4H), 7.32 (m, 4H), 5.73 (s, 4H), 1.74 (s,60H) ppm. 13 C{ 1 H} NMR (100 MHz, CD3CN): δ = 184.4, 152.9, 150.6, 143.4, 142.0,128.8, 127.4, 124.8, 123.7, 120.5, 109.3, 102.5, 96.9, 96.8, 94.5, 89.5, 9.0ppm.

[0028] like Figure 1 As shown, it is the single crystal structure diagram of azulenyl organometallic ring 3a. Figure 4 is the H NMR spectrum of azulenyl organometallic ring 3a, Figure 5 The UV absorption spectra of the azulenyl organic ligand 2a and the azulenyl organometallic ring 3a.

[0029] Example 2: Preparation of azulenyl organometallic ring 3b

[0030] Under anhydrous and oxygen-free conditions, dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer (0.01 mmol) was added to 1 mL of methanol solution, followed by 0.04 mmol of AgOTf, and the mixture was stirred at room temperature for 12 h in the dark. After the reaction was completed, the mixture was centrifuged, the supernatant solution was removed, and 0.01 mmol of benzoquinone and 80 mmol / L methanol solution containing NaOH were added, and the mixture was stirred at room temperature in the dark for another 12 h. 0.01 mmol of azulenyl organic ligand 2b was dissolved in 0.5 mL of DMA solution and added to the above mixed solution. The mixture was stirred at room temperature for 24 h in the dark. After the reaction was completed, the mixture was centrifuged, the supernatant solution was removed, and single crystals of azulenyl organometallic ring 3b were obtained by diffusion method with a yield of 45%. The structural formula is:

[0031]

[0032] like Figure 2 Shown is the single crystal structure of the azulenyl organometallic ring 3b.

[0033] Example 3: Preparation of azulenyl organometallic ring 3c

[0034] Under anhydrous and oxygen-free conditions, dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer (0.01 mmol) was added to 1 mL of methanol solution, followed by 0.04 mmol of AgOTf, and the reaction was stirred at room temperature for 12 h in the dark. After the reaction was completed, the solution was centrifuged, the supernatant was removed, and 0.01 mmol of benzoquinone and 80 mmol / L of methanol containing NaOH were added, and the reaction was continued at room temperature in the dark for 12 h. 0.01 mmol of azulenyl organic ligand 2c was dissolved in 0.5 mL of DMA solution and added to the above mixed solution. The reaction was stirred at room temperature for 24 h in the dark. After the reaction was completed, the solution was centrifuged, the supernatant was removed, and single crystals of organometallic ring 3c were obtained by diffusion method with a yield of 41%. The structural formula is:

[0035]

[0036] like Figure 3 Shown is the single crystal structure of the azulenyl organometallic ring 3c.

[0037] Example 4: Photocatalytic test

[0038] The organometallic ring 3 synthesized by the above method was added to methanol as a photocatalyst together with thioanisole. The mixed solution was placed in a reaction tube and reacted under O2 atmosphere and visible light for 4 hours. The amounts of each reactant were 0.1 mmol of thioanisole, 1 mL of methanol, and 2.5 mg of catalyst.

[0039] After the reaction is complete, the solvent is removed, ether is added, the supernatant is collected, and it is spin-dried. The product is analyzed by NMR. The homogeneous catalyst after the reaction is washed three times with ether, naturally dried, and recycled for the next time;

[0040] The reaction formula is:

[0041]

[0042] In the above-mentioned thioanisole oxidation reaction, the yield of the product was 92%.

[0043] 1 H NMR (400 MHz, CDCl3): δ 7.63-7.60 (m, 2H), 7.50-7.48 (m, 3H), 2.69 (s, 3H).

[0044] Table 1 shows the yields of different sulfide derivatives in the oxidation reaction over homogeneous catalyst 3. It can be seen that the catalyst has universal applicability; in addition, it can be seen that the oxidation yield of sulfide derivatives can reach up to 96%.

[0045] Table 1 Different reaction substrates and product yields

[0046]

[0047] The above detailed description of the analytical methods involved in the present invention provides a detailed introduction. It should be noted that the above description is intended solely to help those skilled in the art better understand the methods and concepts of the present invention, and is not intended to limit the relevant content. Without departing from the principles of the present invention, those skilled in the art may make appropriate adjustments or modifications to the present invention, and such adjustments and modifications shall also fall within the scope of protection of the present invention.

Claims

1. A method for synthesizing an azulenyl organometallic ring, characterized in that: Azulenyl organometallic ring 3 was synthesized via a one-pot method using binuclear compound 1 and azulenyl organic ligand 2 as raw materials. The reaction equation is shown below: The specific steps are as follows: Under anhydrous and oxygen-free operating conditions, dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer was added to a methanol solution, followed by the addition of AgOTf, and the reaction was stirred at room temperature for 12 h in the dark. After the reaction was completed, the solution was centrifuged, the supernatant solution was taken, and benzoquinone and 80 mmol / L methanol solution containing NaOH were added, and the solution was stirred at room temperature in the dark for 12 h to obtain compound 1; the azulene organic ligand 2 was dissolved in DMA and added to the above reaction solution, and the reaction was stirred at room temperature for 24 h in the dark; after the reaction was completed, the solution was centrifuged, the supernatant solution was taken, and the product, i.e., a single crystal of azulene organic metal ring 3, was obtained by diffusion method.

2. The method for synthesizing an azulenyl organometallic ring according to claim 1, wherein: The azulenyl organic ligand 2 is any one of the following structural formulas:

3. The method for synthesizing an azulenyl organometallic ring according to claim 1, wherein: The molar ratio of the dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer to AgOTf is 1:2 to 1:

10.

4. The method for synthesizing an azulenyl organometallic ring according to claim 3, wherein: The molar ratio of the dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer and AgOTf is 1:

6.

5. The method for synthesizing an azulenyl organometallic ring according to claim 1, wherein: The molar ratio of the binuclear compound 1 and the azulenyl organic ligand 2 is 1:1 to 1:

2.

6. The method for synthesizing an azulenyl organometallic ring according to claim 5, wherein: The molar ratio of the binuclear compound 1 and the azulenyl organic ligand 2 is 1:

1.

7. Use of the azulenyl organometallic ring obtained by the synthesis method according to claim 1 in a photocatalytic reaction.

8. The use according to claim 7, characterized in that Application as a catalyst in the photocatalytic thioanisole reaction.

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