A heterogeneous bipyridine ruthenium compound and its preparation method and use

Abstract

The present invention discloses a heterogeneous ruthenium bipyridine compound, its preparation method, and use. The compound is Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2. The preparation method comprises reacting Ru(CF3-bpy)2Cl2·2H2O and 4,4'-tert-butyl-2,2'-bipyridine (t-Bu-bpy) in ethanol and distilled water under an inert gas for a period of time, removing the ethanol, cooling to room temperature, and adding KPF6 to obtain an orange-red target product. Compared with the prior art, the ruthenium compound prepared in the present invention has a completely new structure and can be used as a photocatalyst. The preparation method is simple and does not require further purification.

Description

Technical Field

[0001] The present invention relates to a ruthenium bipyridine compound and a preparation method thereof, in particular to a heterogeneous ruthenium bipyridine compound Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2 and a preparation method and application thereof. Background Art

[0002] Visible-light photoredox catalysis in organic synthesis offers advantages such as mild reaction conditions and is widely used in reactions such as coupling, cyclization, and asymmetric catalysis, encompassing a wide range of industrial and biomedical applications. Ruthenium compounds exhibit photostability, strong visible light absorption, long excited states in the microsecond range, and the ability to participate in single electron transfer (SET) processes. They can be used to catalyze a variety of reactions, including olefin reduction, free radical cyclization, oxidative coupling, and atom transfer radical addition.

[0003] There is a clear relationship between the structural characteristics and redox properties of ruthenium compounds, and the absorption and emission spectra can be effectively controlled by modifying them with different ligands. Ruthenium complexes are currently widely used as photocatalysts in organic synthesis due to their long excited state lifetime, which allows them to persist for extended periods of time.

[0004] To date, the synthesis method of ruthenium photosensitizers mainly uses hydrated ruthenium trichloride as the raw material, which reacts with bipyridine ligands to obtain a ruthenium dichloride bipyridine complex. Then, using the ruthenium dichloride bipyridine complex as the starting material, ruthenium photosensitizers are synthesized through two routes. The synthesis routes are:

[0005]

[0006] Route 1 involves dissolving the ruthenium dichloride bipyridine complex and the N^N ligand in ethylene glycol, refluxing for 8 hours, then adding anions. The solid is collected and purified by column chromatography to obtain the ruthenium photosensitizer in yields ranging from 75% to 90%. Route 2, a milder synthesis method, involves dissolving the ruthenium dichloride bipyridine complex and the N^N ligand in methanol and water, refluxing for 20 hours, cooling to room temperature, filtering under reduced pressure, drying, and then purifying by column chromatography. After adding anions, the ruthenium photosensitizer is obtained in yields ranging from 70% to 80%.

[0007] The above-mentioned synthesis methods all have the problem of requiring purification in the later stage.

[0008] Therefore, finding simple synthesis methods and new structural ruthenium photosensitizers is an important direction for the development of photocatalysts. Summary of the Invention

[0009] The purpose of the present invention is to overcome the defects of the prior art and provide a heterogeneous bipyridine ruthenium compound with a completely new structure and a preparation method and use thereof.

[0010] The purpose of the present invention can be achieved by the following technical solutions:

[0011] A heterogeneous ruthenium bipyridine compound Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2, whose molecular structure is shown below:

[0012]

[0013] Its preparation route is as follows:

[0014]

[0015] The preparation method of the invention comprises the steps of synthesizing a heterogeneous ruthenium bipyridine compound by using Ru(CF3-bpy)2Cl2, 4,4'-di-tert-butyl-2,2'-bipyridine (t-Bu-bpy) and KPF6 as raw materials in the presence of ethanol and distilled water.

[0016] The specific steps are: under inert gas, Ru(CF3-bpy)2Cl2·2H2O and 4,4'-tert-butyl-2,2'-bipyridine (t-Bu-bpy) react in ethanol and water for a period of time, then remove the ethanol, cool to room temperature, and add KPF6 to obtain the target product Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2.

[0017] The heterogeneous bipyridine ruthenium compound of the present invention can be used as a photocatalyst.

[0018] Beneficial effects of the present invention:

[0019] The heterogeneous bipyridine ruthenium compound photocatalyst of the present invention has a simple synthesis method and does not require further purification. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding 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:

[0021] Figure 1 : Hydrogen spectrum of Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2 prepared by the present invention.

[0022] Figure 2 : Carbon spectrum of Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2 prepared by the present invention.

[0023] Figure 3 : Mass spectrum of Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2 prepared by the present invention.

[0024] Figure 4 : Infrared spectrum of Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2 prepared by the present invention.

[0025] Figure 5 : Ultraviolet-visible absorption spectrum of Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2 prepared by the present invention.

[0026] Figure 6 : Photoluminescence spectrum of Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2 prepared by the present invention. DETAILED DESCRIPTION

[0027] The following is a detailed description of specific implementation cases of the present invention. It should be understood that the specific implementation cases described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0028] The points and any values ​​of the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and 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 herein.

[0029] In the following examples, the raw material Ru(CF3-bpy)2Cl2·2H2O was prepared by the method disclosed in the literature "Efficient electron transfer through a triazole link in ruthenium(II)polypyridine type complexes" (Chem. Commun., 2011, 47, 11011-11013, DOI 10.1039 / C1CC13683F).

[0030] Example 1

[0031] Under inert gas, a reaction flask was added with 1 g (1.27 mmol) of Ru(CF3-bpy)2Cl2·2H2O and 0.41 g (1.52 mmol) of 4,4'-di-tert-butyl-2,2'-bipyridine (t-Bu-bpy). 25 mL of ethanol and 12.5 mL of deionized water were then added and the mixture was allowed to react at 80°C for 20 h. The mixture was cooled to room temperature, the ethanol was evaporated, and 0.56 g (3 mmol) of KPF6 was added. The reaction was stirred for another 0.5 h, filtered, and the filter cake was rinsed with deionized water and dried under vacuum for 6 h to obtain 1.44 g of an orange-red solid sample with a yield of 91.2%.

[0032] Example 2

[0033] Under inert gas, a reaction flask was added with 5 g (6.33 mmol) of Ru(CF3-bpy)2Cl2·2H2O and 2.04 g (7.60 mmol) of 4,4'-di-tert-butyl-2,2'-bipyridine (t-Bu-bpy). 125 mL of ethanol and 62.5 mL of deionized water were then added and the mixture was allowed to react at 80°C for 20 h. The mixture was cooled to room temperature, the ethanol was evaporated, and 2.80 g (15.2 mmol) of KPF6 was added. The reaction was stirred for another 1 h, filtered, and the filter cake was rinsed with deionized water and dried under vacuum for 6 h to obtain 7.28 g of an orange-red solid sample with a yield of 92.5%.

[0034] Example 3

[0035] The structural analysis of the samples prepared in Examples 1 and 2 includes:

[0036] (1) Elemental analysis, theoretical value (%): C 40.56, H 2.89; measured value (%): C 40.55, H 2.93. The measured values ​​are consistent with the theoretical values.

[0037] (2) Hydrogen spectrum ( 1 H NMR, 500 MHz, DMSO-d6, as Figure 1 Chemical shift (ppm): 9.20 (dd, J = 8.7, 4.9 Hz, 4H), 8.81 (d, J = 2.2 Hz, 2H), 8.74 (dd, J = 8.7, 2.0 Hz, 4H), 8.02 (d, J = 2.0 Hz, 2H), 7.75 (d, J = 2.0 Hz, 2H), 7.65 (d, J = 6.0 Hz, 2H), 7.57 (dd, J = 6.1, 2.0 Hz, 2H), 1.40 (s, 18H).

[0038] (3) Carbon spectrum ( 13 C NMR, 500 MHz, DMSO-d6, as Figure 2 Chemical shifts (ppm): 162.91, 159.69, 159.10, 156.31, 152.21, 149.16, 147.88, 135.81, 135.68, 128.68, 128.41, 128.07, 126.22, 124.60, 123.16, 121.71, 120.99, 35.58, 29.96.

[0039] (4) Mass spectrometry (ESI-MS, such as Figure 3 As shown), a molecular ion peak of 1099 appeared, which is [Ru(CF3-bpy)2(t-Bu-bpy)PF6]+ The molecular weight of the product was consistent with that of the target product.

[0040] (5) Infrared spectrum IR (cm -1 , KBr pellets, such as Figure 4 shown), 558cm -1 The absorption peak at 1145 cm is attributed to the characteristic peak of Ru-N coordination bond vibration. -1 The absorption peak at 1328 cm is attributed to the characteristic peak of CF vibration. -1 The absorption peak at 1617 cm is attributed to the characteristic peak of CN vibration. -1 The absorption peak is attributed to the characteristic peak of C=N vibration.

[0041] (6) UV-visible absorption spectra (such as Figure 5 As shown), the strong absorption peak at 280nm is the ligand spin-allowed πL→π * L transition, the broad low absorption band between 400-550 nm is attributed to the spin-allowed singlet metal to ligand charge transfer band (1MLCT).

[0042] (7) Photoluminescence spectroscopy (e.g. Figure 6 As shown), at room temperature, the maximum emission wavelength of Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2 in acetonitrile is 687nm.

[0043] (8) Analysis conclusion

[0044] The above-mentioned elemental analysis, hydrogen spectrum, carbon spectrum, mass spectrum and infrared spectrum test results show that the sample is consistent with the target Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2.

[0045] In summary, the present invention provides a new structure and preparation method, which is simple to operate, concise to purify, has few steps and high yield.

[0046] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a heterogeneous bipyridine ruthenium compound, characterized in that: by It is synthesized using ethanol and distilled water as raw materials, and 4,4'-di-tert-butyl-2,2'-bipyridine as the preparation route: ； The amount of ethanol added is the raw material 25 times the mass; The added mass of the distilled water is the raw material 12.5 times the mass; The specific steps include: under inert gas, After reacting with 4,4'-di-tert-butyl-2,2'-bipyridine in ethanol and distilled water for a period of time, the mixture was cooled to room temperature, the ethanol was dried by spin drying, KPF6 was added to react, and the mixture was filtered and dried to obtain the target compound.

2. The preparation method according to claim 1, characterized in that described : The molar ratio of 4,4'-di-tert-butyl-2,2'-bipyridine:KPF6 is 1:1.2:2.

4.

3. The preparation method according to claim 1, characterized in that The reaction is carried out at 80° C. for 12 to 24 hours; and the addition of KPF6 reaction includes stirring for 0.5 to 2 hours.

4. The preparation method according to any one of claims 1 to 3, characterized in that The filtration and drying process includes filtering the filter cake and rinsing with deionized water, and vacuum drying for more than 6 hours to obtain an orange-red solid. .

Images