Heterogeneous bipyridine ruthenium compound as well as preparation method and application thereof

Abstract

The invention discloses a heterogeneous bipyridine ruthenium compound as well as a preparation method and application thereof. The compound is Ru (CF3-bpy) 2 (t-Bu-bpy) (PF6) 2. The preparation method comprises the following steps: under inert gas, Ru (CF3-bpy) 2Cl2. 2H2O and 4, 4 '-tert-butyl-2, 2'-dipyridyl (t-Bu-bpy) react in ethanol and distilled water for a period of time, then ethanol is screwed out, the mixture is cooled to room temperature, KPF6 is added, and an orange red target product is obtained. Compared with the prior art, the prepared ruthenium compound with the brand new structure can be used as a photocatalyst, the preparation method is simple, and further purification is not needed.

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 catalytic organic synthesis has the advantages of mild reaction conditions and is widely used in reactions such as coupling, cyclization and asymmetric catalysis, and is widely used in various industries, biomedicine and other fields. Ruthenium compounds have photostability, strong absorption in the visible light region, long excited states in the microsecond range, and can participate in the single electron transfer (SET) process. They can be used to catalyze a variety of reactions such as olefin reduction, free radical cyclization, oxidative coupling, and atom transfer radical addition.

[0003] There is an obvious relationship between the structural characteristics and redox properties of ruthenium compounds, and the range of absorption and emission spectra can be effectively regulated by modifying different ligands. Its excited state has a long lifetime, which allows the excited state to exist for a long time, so ruthenium complexes are currently widely used as photocatalysts in organic synthesis.

[0004] Up to now, the synthesis method of ruthenium photosensitizer mainly uses hydrated ruthenium trichloride as raw material, reacts with bipyridine ligand to obtain dichlororuthenium bipyridine complex. Then, using dichlororuthenium bipyridine complex as starting material, ruthenium photosensitizer is synthesized by two routes respectively. The synthesis route is:

[0005]

[0006] Route 1 is to dissolve the dichlororuthenium bipyridine complex and N^N ligand in ethylene glycol, reflux for 8 hours, then add anions, collect the solid and purify it by column chromatography to obtain a ruthenium photosensitizer with a yield of 75% to 90%. Route 2 is a milder synthesis method, dissolving the dichlororuthenium bipyridine complex and N^N ligand in methanol and water, reflux for 20 hours, cooling to room temperature, filtering and drying under reduced pressure, purifying it by column chromatography, adding anions, and obtaining a ruthenium photosensitizer with a yield of 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 bipyridine ruthenium compound Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2, whose molecular structure is shown below:

[0012]

[0013] The preparation route is as follows:

[0014]

[0015] The preparation method of the invention comprises the steps of using Ru(CF3-bpy)2Cl2, 4,4'-di-tert-butyl-2,2'-bipyridine (t-Bu-bpy) and KPF6 as raw materials to synthesize a heterogeneous bipyridine ruthenium compound under the conditions 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) are reacted in ethanol and water for a period of time, the ethanol is removed, cooled to room temperature, and KPF6 is added 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 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:

[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 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.

[0028] 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.

[0029] In the following examples, the raw material Ru(CF3-bpy)2Cl2·2H2O source was prepared by the method disclosed in the document “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, add 1g (1.27mmol) Ru (CF3-bpy) 2Cl2 · 2H2O and 0.41g (1.52mmol) 4,4'-di-tert-butyl-2,2'-bipyridine (t-Bu-bpy) to the reaction bottle, then add 25mL ethanol and 12.5mL deionized water, and react at 80℃ for 20h. Cool to room temperature, spin dry ethanol, add 0.56g (3mmol) KPF6, continue stirring and reacting for 0.5h, filter, rinse the filter cake with deionized water, and vacuum dry for 6h to obtain 1.44g orange-red solid sample with a yield of 91.2%.

[0032] Example 2

[0033] Under inert gas, add 5g (6.33mmol) Ru (CF3-bpy) 2Cl2 · 2H2O and 2.04g (7.60mmol) 4,4'-di-tert-butyl-2,2'-bipyridine (t-Bu-bpy) to the reaction bottle, then add 125mL ethanol and 62.5mL deionized water, and react at 80℃ for 20h. Cool to room temperature, spin dry ethanol, add 2.80g (15.2mmol) KPF6, continue stirring and reacting for 1h, filter, rinse the filter cake with deionized water, and vacuum dry for 6h to obtain 7.28g 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 value is consistent with the theoretical value.

[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 shift (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), there is a molecular ion peak of 1099, 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 tablets, such as Figure 4 As shown), 558cm -1 The absorption peak at 1145cm 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 1617cm 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 The strong absorption peak at 280 nm is the ligand spin-allowed πL→π * L transition, the broad low absorption band between 400-550nm 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 detection results of the above-mentioned elemental analysis, hydrogen spectrum, carbon spectrum, mass spectrum and infrared spectrum 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 brand-new structure and preparation method, the preparation method is simple to operate, simple to purify, has few steps and high yield.

[0046] 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 heterogeneous bipyridine ruthenium compound, characterized in that: The compound is Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2, and its structure is:

2. The heterogeneous bipyridine ruthenium compound according to claim 1, characterized in that: The compound is prepared by coordinating two 5,5'-ditrifluoromethyl-2,2'-bipyridines and one 4,4'-di-tert-butyl-2,2'-bipyridine with ruthenium to form a Ru(N^N)3(PF6)2 structure.

3. The method for preparing a heterogeneous bipyridine ruthenium compound according to claim 1 or 2, characterized in that: The product was synthesized using Ru(CF3-bpy)2Cl2·2H2O and 4,4'-di-tert-butyl-2,2'-bipyridine as raw materials in the presence of ethanol and distilled water. The preparation route is as follows:

4. The preparation method according to claim 3, characterized in that: The specific steps include: under inert gas, Ru(CF3-bpy)2Cl2·2H2O and 4,4'-di-tert-butyl-2,2'-bipyridine react in ethanol and distilled water for a period of time, cooling to room temperature, spinning ethanol, adding KPF6 to react, filtering and drying to obtain the target compound.

5. The preparation method according to claim 4, characterized in that: The molar ratio of Ru(CF3-bpy)2Cl2·2H2O:4,4'-di-tert-butyl-2,2'-bipyridine:KPF6 is 1:1.2:2.

4.

6. The preparation method according to claim 4, characterized in that: The amount of ethanol added is 25 times the mass of the raw material Ru(CF3-bpy)2Cl2·2H2O.

7. The preparation method according to claim 4, characterized in that: The mass of the added distilled water is 12.5 times the mass of the raw material Ru(CF3-bpy)2Cl2·2H2O.

8. The preparation method according to claim 4, characterized in that: The reaction is carried out at 80° C. for 12 to 24 hours; the addition of KPF6 reaction includes stirring the reaction for 0.5 to 2 hours.

9. The preparation method according to any one of claims 4 to 8, characterized in that: The filtration and drying comprises filtering the filter cake and rinsing with deionized water, and vacuum drying for more than 6 hours to obtain an orange-red solid Ru(CF3-bpy)2(t-Bu-bpy)(PF6)2.

10. Use of a heterogeneous bipyridine ruthenium compound according to claim 1 or 2 in a photocatalyst.

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