Method for preparing tris(4,7-biphenyl-1,10-phenanthroline)ruthenium dichloride

Abstract

The present invention provides a method for preparing tris(4,7-biphenyl-1,10-phenanthroline)ruthenium dichloride having an increased yield. The method comprises the following steps: (1) dissolving 4,7-biphenyl-1,10-phenanthroline in an alcohol solution, adding a ruthenium trichloride hydrate, reacting the mixture, and filtering to obtain a reaction solution; (2) dropwise adding to the reaction solution obtained in step (1) a solution for dissolving a hexafluorophosphate in distilled water to obtain a tris(4,7-biphenyl-1,10-phenanthroline)ruthenium hexafluorophosphate solid, wherein the hexafluorophosphate is 2-4 eq with respect to the ruthenium trichloride hydrate; and (3) dissolving the tris(4,7-biphenyl-1,10-phenanthroline)ruthenium hexafluorophosphate solid obtained in step (2) in acetone and dropwise adding to the obtained solution a solution for dissolving tetraalkylammonium chloride in acetone to obtain tris(4,7-biphenyl-1,10-phenanthroline)ruthenium dichloride, wherein the tetraalkylammonium chloride is 2-4 eq with respect to the ruthenium trichloride hydrate.

Description

A method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride Technical Field

[0001] This invention relates to a method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride. Background Technology

[0002] Currently, ruthenium tris(4,7-biphenyl-1,10-o-phenanthroline)dichloride ((Ru(dpp)3)Cl2) is widely used as a probe in luminescent detection and quantitative oxygen determination. Optical dissolved oxygen sensors based on the fluorescence quenching principle offer advantages such as not consuming oxygen, requiring no reference electrode, high measurement accuracy, high sensitivity, and immunity to electromagnetic interference, better meeting the needs of real-time online monitoring. Therefore, ruthenium tris(4,7-biphenyl-1,10-o-phenanthroline)dichloride is an effective oxygen probe based on intensity or decay time measurements. Ruthenium tris(4,7-biphenyl-1,10-o-phenanthroline)dichloride has been used in (fiber) optical sensors, oxygen research in skin and skin tumors, measurement of oxygen flux in the skin, and oxygen imaging.

[0003] Currently, the preparation methods for tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride have low yields. For example, existing methods for synthesizing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride (Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2014, vol. 130, pp. 553-560) require elution with large amounts of solvent. This preparation method has very strict requirements on the amount of 4,7-biphenyl-1,10-o-phenanthroline used as a raw material, and the amount used has a significant impact on the yield.

[0004] Currently, there is no simple and high-yield method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride.

[0005] Summary of the Invention

[0006] The problem to be solved by the present invention

[0007] Currently, in the synthesis of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride, the yield is low because the 4,7-biphenyl-1,10-o-phenanthroline used as a raw material has the same color and polarity as the target product tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride, byproducts, and impurities. Furthermore, the amount of 4,7-biphenyl-1,10-o-phenanthroline used as a raw material needs to be strictly controlled. As shown in Comparative Examples 1 and 2 described later, variations in the amount of 4,7-biphenyl-1,10-o-phenanthroline used as a raw material have a significant impact on the yield of the target product. Moreover, existing preparation methods result in products with extremely poor solubility, complex operations, and low yields.

[0008] In view of the problems in the prior art, the object of the present invention is to provide a method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride, in which the change in the amount of 4,7-biphenyl-1,10-o-phenanthroline used as a raw material has a reduced impact on the yield of the target product and the yield is improved.

[0009] Methods for solving problems

[0010] The technical solution of the present invention is as follows.

[0011] [1] A method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride, characterized by comprising the following steps:

[0012] (1) Dissolve 4,7-biphenyl-1,10-o-phenanthroline in an alcohol solution, add ruthenium trichloride hydrate to react, and filter to obtain the reaction solution;

[0013] (2) Add a solution of hexafluorophosphate dissolved in distilled water to the reaction solution obtained in (1) to obtain tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate solid, wherein the molar ratio of hexafluorophosphate to ruthenium trichloride hydrate is 2 to 4:1;

[0014] (3) The solid tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate obtained in (2) is filtered out and dissolved in acetone, and a solution of tetraalkylammonium chloride or aryltrialkylammonium chloride dissolved in acetone is added dropwise to precipitate the solid and filter it out to obtain tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride, wherein the number of carbon atoms of the alkyl group is 1 to 5 and the number of carbon atoms of the aryl group is 7 or less, wherein the molar ratio of the tetraalkylammonium chloride or aryltrialkylammonium chloride to ruthenium trichloride hydrate is 2 to 4:1.

[0015] [2] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to [1] is characterized in that the tetraalkyl ammonium chloride is selected from one or more of tetramethyl ammonium chloride, tetraethyl ammonium chloride, tetrapropyl ammonium chloride, tetrabutyl ammonium chloride, tetrapentyl ammonium chloride, and methyltributyl ammonium chloride, and the aryltrialkyl ammonium chloride is benzyltributyl ammonium chloride.

[0016] [3] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to [1] is characterized in that the tetraalkylammonium chloride is tetramethylammonium chloride or tetrabutylammonium chloride.

[0017] [4] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to [1] is characterized in that the hexafluorophosphate is selected from one or more of ammonium hexafluorophosphate, potassium hexafluorophosphate, and sodium hexafluorophosphate.

[0018] [5] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to [1] is characterized in that the tetraalkylammonium chloride is tetrabutylammonium chloride and the hexafluorophosphate is ammonium hexafluorophosphate.

[0019] [6] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to [1] is characterized in that the molar ratio of 4,7-biphenyl-1,10-o-phenanthroline to ruthenium trichloride hydrate is 3 to 5:1.

[0020] [7] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to [1] is characterized in that the ratio of 4,7-biphenyl-1,10-o-phenanthroline to ruthenium trichloride hydrate is 3:1.

[0021] [8] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to [1] is characterized in that the molar ratio of hexafluorophosphate to ruthenium trichloride hydrate is 2:1.

[0022] [9] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to [1] is characterized in that the molar ratio of the tetraalkylammonium chloride or aryltrialkylammonium chloride to ruthenium trichloride hydrate is 2:1.

[0023]

[0010] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to [1] is characterized in that the molar ratio of hexafluorophosphate: tetraalkylammonium chloride or aryltrialkylammonium chloride: ruthenium trichloride hydrate is 2:2:1.

[0024] The effects of the invention

[0025] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride of the present invention is simple, can easily obtain the target compound, has a high yield, is less affected by the amount of raw materials used, can stably obtain a high yield, and has good operability in post-processing, making it suitable for scale-up production and having broad application prospects. Attached Figure Description

[0026] Figure 1 shows the 1H NMR spectrum of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride obtained in Example 1.

[0027] Figure 2 is the mass spectrum of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride obtained in Example 1. Detailed Implementation

[0028] The specific embodiments of the present invention will be further explained and described below with reference to specific examples; however, such explanation and description do not constitute a limitation on the technical solution of the present invention. In the present invention, the target product is tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride.

[0029] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride of the present invention includes the following steps:

[0030] (1) Dissolve 4,7-biphenyl-1,10-o-phenanthroline in an alcohol solution, add ruthenium trichloride hydrate to react, and filter to obtain the reaction solution;

[0031] (2) Add a solution of hexafluorophosphate dissolved in distilled water to the reaction solution obtained in (1) to obtain tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate solid, wherein the molar ratio of hexafluorophosphate to ruthenium trichloride hydrate is 2 to 4:1;

[0032] (3) The solid tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate obtained in (2) is filtered out and dissolved in acetone, and a solution of tetraalkylammonium chloride or aryltrialkylammonium chloride dissolved in acetone is added dropwise to precipitate the solid and filter it out to obtain tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride, wherein the number of carbon atoms of the alkyl group is 1 to 5 and the number of carbon atoms of the aryl group is 7 or less, wherein the molar ratio of the tetraalkylammonium chloride or aryltrialkylammonium chloride to ruthenium trichloride hydrate is 2 to 4:1.

[0033] (Step (1))

[0034] In step (1), 4,7-biphenyl-1,10-o-phenanthroline is dissolved in an alcohol solution, and trichloride hydrate is added. The reaction can be initiated by heating, followed by cooling to 25°C. For easier subsequent processing, the solution can be filtered, and 2 / 3 of the solvent can be removed from the filtrate by rotary evaporation to obtain the reaction solution.

[0035] There is no specific limitation on the alcohol used, as long as it can dissolve 4,7-biphenyl-1,10-o-phenanthroline, such as EtOH. For higher yield, the ratio of 4,7-biphenyl-1,10-o-phenanthroline to the alcohol solution is 1 g: 10–30 ml. Considering better dissolution of 4,7-biphenyl-1,10-o-phenanthroline and subsequent solvent removal, the ratio of 4,7-biphenyl-1,10-o-phenanthroline to the alcohol solution is preferably 1 g: 24 ml. For better reaction performance, the heating temperature is 70–90 °C, more preferably 80 °C.

[0036] According to the method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride of the present invention, the amount of 4,7-diphenyl-1,10-phenanthroline used as a raw material has little effect on the yield of the target product. Therefore, there is no strict requirement for an upper limit. To improve the yield of the target product, the amount of 4,7-biphenyl-1,10-o-phenanthroline used can be 3 mol or more relative to 1 mol of ruthenium trichloride hydrate; to reduce byproducts and impurities, it can be 5 mol or less.

[0037] (Step (2))

[0038] In step (2), a solution of hexafluorophosphate dissolved in distilled water is added dropwise to the reaction solution obtained in step (1) to obtain tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate solid. To reduce byproducts and increase the yield of the target product, it is preferable to slowly add the hexafluorophosphate aqueous solution to the reaction solution at a rate of 2–3 ml / min.

[0039] Specifically, to achieve a higher yield of the target product, the molar ratio of hexafluorophosphate to ruthenium trichloride hydrate is 2 eq or more, and preferably 4 eq or less, to minimize impurities in the product. That is, the molar ratio of hexafluorophosphate to ruthenium trichloride hydrate is 2–4:1. For achieving a higher yield of the target product, the molar ratio of hexafluorophosphate to ruthenium trichloride hydrate is preferably 2 eq, and the molar ratio of hexafluorophosphate to ruthenium trichloride hydrate is preferably 2:1.

[0040] The aforementioned hexafluorophosphate is selected from one or more of ammonium hexafluorophosphate, potassium hexafluorophosphate, and sodium hexafluorophosphate. Ammonium hexafluorophosphate is preferred for achieving a higher yield of the target product.

[0041] (Step (3))

[0042] In step (3), the tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate obtained in step (2) is filtered out and dissolved in acetone. From the perspective of solvent removal, the tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate solid obtained in step (2) can be filtered out, washed with ethanol and water in sequence, and dried to obtain tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate.

[0043] The amount of tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate to acetone is not particularly limited, as long as the acetone is sufficient to completely dissolve the tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate. In a solution of tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate dissolved in acetone, a solution of tetraalkylammonium chloride or aryltrialkylammonium chloride dissolved in acetone is slowly added dropwise, precipitating tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride solid, which is then filtered out.

[0044] To reduce byproducts and increase the yield of the target product, it is preferable to slowly add a tetraalkylammonium chloride or aryltrialkylammonium chloride solution dropwise to the reaction solution at a rate of 2-3 ml / min. Tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride is a red solid. To remove the solvent, the red solid can be filtered out, and the solid tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride is washed with acetone. The four alkyl groups in the tetraalkylammonium chloride can be the same or different, but are preferably the same. For example, the tetraalkylammonium chloride is selected from one or more of tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetrapentylammonium chloride, and methyltributylammonium chloride. To obtain a higher yield of tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride, it is preferable that the tetraalkylammonium chloride is tetramethylammonium chloride or tetrabutylammonium chloride, and the aryltrialkylammonium chloride is benzyltributylammonium chloride, more preferably tetrabutylammonium chloride.

[0045] For achieving higher yields, the molar ratio of tetraalkylammonium chloride or aryltrialkylammonium chloride to ruthenium trichloride hydrate is 2 eq or more, and for reducing product impurities, it is 4 eq or less. That is, the molar ratio of the tetraalkylammonium chloride or aryltrialkylammonium chloride to ruthenium trichloride hydrate is 2 to 4:1. For achieving higher yields of the target product, a molar ratio of tetraalkylammonium chloride or aryltrialkylammonium chloride to ruthenium trichloride hydrate of 2 eq is preferred, and a molar ratio of the tetraalkylammonium chloride or aryltrialkylammonium chloride to ruthenium trichloride hydrate of 2:1 is more preferred.

[0046] In the method of the present invention, in order to obtain a higher yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride, the ratio of 4,7-biphenyl-1,10-o-phenanthroline to ruthenium trichloride hydrate is 3 to 5:1, more preferably 3:1; the molar ratio of hexafluorophosphate to tetraalkylammonium chloride to ruthenium trichloride hydrate is 2 to 4:2 to 4:1, preferably 2:2:1.

[0047] This invention achieves a synergistic effect by combining specific hexafluorophosphate and tetraalkylammonium chloride, thereby increasing the yield of the target product. Furthermore, the combined use of hexafluorophosphate and tetraalkylammonium chloride reduces the impact of the amount of 4,7-biphenyl-1,10-o-phenanthroline used as a raw material on the yield.

[0048] The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride of the present invention is simple, can easily obtain the target compound, has a high yield, is less affected by the amount of raw materials used, can stably obtain a high yield, and has good operability in post-processing, making it suitable for scale-up production and having broad application prospects.

[0049] Example

[0050] Example 1

[0051] 4,7-Biphenyl-1,10-phenanthroline (2.50 g, 7.53 mmol) (Maclean, 25 g) was dissolved in 60 mL of EtOH (Maclean, 5 L), and ruthenium trichloride hydrate (0.52 g, 2.51 mmol) (Maclean, 25 g) was added. The mixture was heated to 80 °C and reacted for 24 hours. After cooling to 25 °C, the mixture was filtered, and two-thirds of the solvent was removed from the filtrate using a rotary evaporator (IKARV3eco) to obtain the reaction solution. Ammonium hexafluorophosphate (0.84 g, 5.20 mmol, 2 eq) (Maclean, 500 g) was dissolved in 10 mL of distilled water and slowly added dropwise to the reaction solution over 10 minutes, causing a solid to precipitate. The precipitated solid was filtered off, washed successively with 10 mL of ethanol and 5 mL of water, and dried to obtain 3.40 g of tris(4,7-biphenyl-1,10-phenanthroline)ruthenium hexafluorophosphate. Dissolve the tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate in 10 ml of acetone (Maclean, 500 ml), and slowly add a solution of tetrabutylammonium chloride (1.44 g, 5.20 mmol, 2 eq) (Maclean, 500 g) dissolved in 10 ml of acetone over 10 minutes. A red solid precipitates out. Filter the solution and wash with 10 ml of acetone to obtain 2.80 g of red solid 1.

[0052] The red solid 1 was analyzed using a nuclear magnetic resonance spectrometer (Braker 400MHz, Switzerland) and a mass spectrometer (LC Agilent 1260ⅡMS Agilent 96160A). The resulting spectra are shown in Figures 1 and 2, respectively. Red solid 1: 1 ¹H NMR (DMSO-d₆, 400 MHz) 8.36 (d, 6H), 8.28 (s, 6H), 7.84 (d, 6H), 7.55–7.70 (m, 30H). Therefore, the red solid is the target compound tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride.

[0053] The theoretical yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride was calculated to be 2.93 g. Therefore, the yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride in Example 1 was 92%.

[0054] The reaction in Example 1 was presumed to proceed as follows:

[0055] Example 2

[0056] 4,7-Biphenyl-1,10-phenanthroline (2.50 g, 7.53 mmol) (Maclean, 25 g) was dissolved in 60 mL of EtOH (Maclean, 5 L), and ruthenium trichloride hydrate (0.52 g, 2.51 mmol) (Maclean, 25 g) was added. The mixture was heated to 80 °C and reacted for 24 hours. After cooling to 25 °C, the mixture was filtered, and two-thirds of the solvent was removed from the filtrate using a rotary evaporator (IKARV3eco) to obtain the reaction solution. Ammonium hexafluorophosphate (1.68 g, 10.40 mmol, 4 eq) (Maclean, 500 g) was dissolved in 20 mL of distilled water and slowly added dropwise to the reaction solution over 10 minutes, causing a solid to precipitate. The precipitated solid was filtered off, washed successively with 30 mL of ethanol and 10 mL of water, and dried to obtain 3.20 g of tris(4,7-biphenyl-1,10-phenanthroline)ruthenium hexafluorophosphate. Dissolve the tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate in 30 ml of acetone (Maclean, 500 ml), and slowly add a solution of tetrabutylammonium chloride (2.88 g, 10.40 mmol, 4 eq) (Maclean, 500 g) dissolved in 20 ml of acetone over 10 minutes. A red solid precipitates out. Filter the solution and wash with 10 ml of acetone to obtain 2.65 g of red solid 2.

[0057] Similar to the analysis in Example 1, the red solid 2 was identified as tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride.

[0058] The theoretical yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride was calculated to be 2.93 g. Therefore, the yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride in Example 3 was 90%.

[0059] Example 3

[0060] In Example 3, except that the tetrabutylammonium chloride (2.88 g, 10.60 mmol, 4 eq) (Maclean, 500 G) used in Example 1 was replaced with tetramethylammonium chloride (0.56 g, 5.10 mmol, 2 eq) (Maclean, 500 G), the process was carried out in the same manner as in Example 2, and 2.60 g of red solid 3 was obtained.

[0061] Similar to the analysis in Example 1, the red solid 2 was identified as tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride.

[0062] The theoretical yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride was calculated to be 2.93 g. Therefore, the yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride in Example 3 was 88%.

[0063] Example 4

[0064] In Example 4, except that the tetrabutylammonium chloride (2.88 g, 10.60 mmol, 4 eq) (Maclean, 500 G) used in Example 1 was replaced with benzyltributylammonium chloride (1.59 g, 5.10 mmol, 2 eq) (Maclean, 500 G), the same procedure as in Example 2 was performed to obtain 2.40 g of red solid 3.

[0065] Similar to the analysis in Example 1, the red solid 3 was identified as tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride.

[0066] The theoretical yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride was calculated to be 2.93 g. Therefore, the yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride in Example 4 was 82%.

[0067] Example 5

[0068] In Example 5, except that the 4,7-biphenyl-1,10-o-phenanthroline (2.50 g, 7.53 mmol) (Maclean, 25 G) used in Example 1 was replaced with 4,7-biphenyl-1,10-o-phenanthroline (4.00 g, 12.05 mmol) (Maclean, 25 G), the procedure was the same as in Example 1, with 2.60 g of red solid 4.

[0069] Similar to the analysis in Example 1, the red solid 4 was identified as tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride.

[0070] The theoretical yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride was calculated to be 2.93 g. Therefore, the yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride in Example 5 was 88%.

[0071] Comparative Example 1

[0072] The synthesis methods in existing literature in the background art are used as comparative example 1.

[0073] 4,7-Biphenyl-1,10-o-phenanthroline (2.50 g, 7.53 mmol) (Maclean, 25 G) was dissolved in 60 mL of EtOH, and ruthenium trichloride hydrate (0.52 g, 2.51 mmol) (Maclean, 25 G) was added. The mixture was heated to 80 °C and reacted for 24 hours. The solvent was evaporated to dryness, and then column chromatography (MeOH / DCM = 1 / 100 to 1 / 15) was performed to give 1.40 g of the target compound tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride. The theoretical yield was 3.02 g, and the yield was 46%.

[0074] Comparative Example 2

[0075] Comparative Example 2 was performed in the same manner as Comparative Example 1, except that the amount of 4,7-biphenyl-1,10-o-phenanthroline used (2.50 g, 7.76 mmol) was replaced with 4,7-biphenyl-1,10-o-phenanthroline (3.50 g, 10.87 mmol) (4.2 eq). A final yield of 0.70 g of the target product was obtained, with a theoretical yield of 3.02 g and a yield of 23%.

[0076] Comparative Example 3

[0077] In Comparative Example 3, except that the tetrabutylammonium chloride (2.88 g, 10.60 mmol, 4 eq) (Maclean, 500 G) used in Example 1 was replaced with ammonium chloride (0.27 g, 5.10 mmol, 2 eq) (Maclean, 500 G), the process was carried out in the same manner as in Example 2, yielding 1.40 g of the target product, with a theoretical yield of 2.93 g and a yield of 47%.

[0078] Comparative Example 4

[0079] In Comparative Example 4, except that ammonium hexafluorophosphate (1.68 g, 10.40 mmol, 4 eq) (Maclean, 500 G) used in Example 1 was replaced with ammonium phosphate (0.59 g, 5.10 mmol, 2 eq) (Maclean, 500 G), the process was carried out in the same manner as in Example 2, yielding 2.00 g of the target product, with a theoretical yield of 2.93 g and a yield of 68%.

[0080] In Examples 1-5 above, ammonium hexafluorophosphate was used, specifically tetrabutylammonium chloride, tetramethylammonium chloride, and benzyltributylammonium chloride, respectively. The yields of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride were 92%, 90%, 88%, 82%, and 88%, respectively. The preparation method according to the present invention yields a very high amount of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride. Furthermore, the preparation method of the present invention does not require complex column chromatography, making the operation simple.

[0081] Compared to Example 1, Example 2 increased the amount of tetrabutylammonium chloride and ammonium hexafluorophosphate used. The yield of tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride was slightly lower in Example 2 compared to Example 1.

[0082] Compared to Example 1, in Examples 3 and 4, tetrabutylammonium chloride was replaced with tetramethylammonium chloride and benzyltributylammonium chloride, respectively. The yields of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride in Examples 3 and 4 were 88% and 82%, respectively. Compared to Example 1, the yields of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride in Examples 3 and 4 were slightly lower.

[0083] Example 5 differs from Example 1 only in that 4,7-biphenyl-1,10-o-phenanthroline (2.5 g, 7.53 mmol) in Example 1 is replaced with 4,7-biphenyl-1,10-o-phenanthroline (4.0 g, 7.53 mmol). After increasing the amount of 4,7-biphenyl-1,10-o-phenanthroline (2.5 g, 7.53 mmol) as a starting material by 60%, the yield of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride of the target product is 88%, slightly lower than the 90% in Example 1.

[0084] In contrast, Comparative Examples 1 and 2 prepared tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride by column chromatography according to the synthesis method described in the prior art. The yields of tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride in Comparative Examples 1 and 2 were 47% and 23%, respectively, which are very low compared to the yields of over 80% of the target product in the embodiments of the present invention. Furthermore, column chromatography separation requires expensive chromatography columns, involves complex procedures, produces numerous byproducts, and results in a low yield of the target product.

[0085] Comparative Example 2 differs from Comparative Example 1 only in that the amount of 4,7-biphenyl-1,10-o-phenanthroline (2.50 g, 7.76 mmol) used in Comparative Example 1 was replaced with 4,7-biphenyl-1,10-o-phenanthroline (3.50 g, 10.87 mmol). In Comparative Example 2, after increasing the amount of 4,7-biphenyl-1,10-o-phenanthroline (2.5 g, 7.53 mmol) as a starting material by 60% compared to Comparative Example 1, the yield of tris(4,7-biphenyl-1,10-o-phenanthroline) dichloride of the target product decreased to 23%, compared to 47% in Comparative Example 1. The yield of tris(4,7-biphenyl-1,10-o-phenanthroline) dichloride of the target product decreased significantly after increasing the amount of starting material.

[0086] Therefore, it can be seen that, compared with the prior art, the yield of the target product tris(4,7-biphenyl-1,10-o-phenanthroline) dichloride obtained by the method of the present invention is less affected by the amount of raw material used. By using the preparation method of tris(4,7-biphenyl-1,10-o-phenanthroline) dichloride of the present invention, a stable high yield can be obtained.

[0087] Comparative Example 3 used ammonium chloride instead of the ammonium salt used in Example 1. The yield of tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride in Comparative Example 3 was only 47%, a significant decrease compared to the examples. Therefore, although ammonium hexafluorophosphate was used in Comparative Example 3 as in Example 2, the yield of the target product was very low when using the same molar amount of ammonium chloride but without the tetraalkylammonium salt specified in this application, and the effects of the present invention could not be obtained.

[0088] Comparative Example 4 differs from Example 1 only in that ammonium hexafluorophosphate is replaced with ammonium phosphate, resulting in a yield of only 68% for tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride. Compared to Example 2, the yield of tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride in Comparative Example 4 is significantly reduced. Therefore, although tetrabutylammonium chloride was used in Comparative Example 4, similar to Example 2, the yield of the target product was very low when using the same molar amount of ammonium phosphate but without using the hexafluorophosphate specific to this application, thus failing to achieve the effects of the present invention.

[0089] As can be seen from the above, the preparation method of tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride of the present invention is simple, can conveniently obtain the target compound, and has a high yield. The influence of the amount of 4,7-biphenyl-1,10-o-phenanthroline used on the yield of the target product is reduced, and a high yield can be obtained stably. The post-processing has good operability, is suitable for scale-up production, and has broad application prospects.

[0090] It should be noted that the scope of protection of this invention is not limited to the embodiments given in this application. All prior art that does not contradict the solution of this invention, including but not limited to prior patent documents, prior publications, prior uses, etc., can be included in the scope of protection of this invention. Furthermore, the combination of technical features in this application is not limited to the combinations described in the claims or the specific embodiments. All technical features described in this application can be freely combined or combined in any way, unless they contradict each other.

[0091] It should also be noted that the embodiments listed above are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made thereto are those that can be directly derived or easily conceived by those skilled in the art from the content disclosed in the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride, characterized in that, Includes the following steps: (1) Dissolve 4,7-biphenyl-1,10-o-phenanthroline in an alcohol solution, add ruthenium trichloride hydrate to react, and filter to obtain the reaction solution; (2) Add a solution of hexafluorophosphate dissolved in distilled water to the reaction solution obtained in (1) to obtain tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate solid, wherein the molar ratio of hexafluorophosphate to ruthenium trichloride hydrate is 2 to 4:1; (3) The solid tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium hexafluorophosphate obtained in (2) is filtered out and dissolved in acetone, and a solution of tetraalkylammonium chloride or aryltrialkylammonium chloride dissolved in acetone is added dropwise to precipitate the solid and filter it out to obtain tris(4,7-biphenyl-1,10-o-phenanthroline)ruthenium dichloride, wherein the number of carbon atoms of the alkyl group is 1 to 5 and the number of carbon atoms of the aryl group is 7 or less, wherein the molar ratio of the tetraalkylammonium chloride or aryltrialkylammonium chloride to ruthenium trichloride hydrate is 2 to 4:

1.

2. The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to claim 1, characterized in that, The tetraalkylammonium chloride is selected from one or more of tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetrapentylammonium chloride, and methyltributylammonium chloride, and the aryltrialkylammonium chloride is benzyltributylammonium chloride.

3. The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to claim 1, characterized in that, The tetraalkylammonium chloride is tetramethylammonium chloride or tetrabutylammonium chloride.

4. The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to claim 1, characterized in that, The hexafluorophosphate is selected from one or more of ammonium hexafluorophosphate, potassium hexafluorophosphate, and sodium hexafluorophosphate.

5. The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to claim 1, characterized in that, The tetraalkylammonium chloride is tetrabutylammonium chloride, and the hexafluorophosphate is hexafluorophosphate.

6. The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to claim 1, characterized in that, The ratio of 4,7-biphenyl-1,10-o-phenanthroline to ruthenium trichloride hydrate is 3 to 5:

1.

7. The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to claim 1, characterized in that, The ratio of 4,7-biphenyl-1,10-o-phenanthroline to ruthenium trichloride hydrate is 3:

1.

8. The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to claim 1, characterized in that, The molar ratio of hexafluorophosphate to ruthenium trichloride hydrate is 2:

1.

9. The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to claim 1, characterized in that, The molar ratio of the tetraalkylammonium chloride or aryltrialkylammonium chloride to ruthenium trichloride hydrate is 2:

1.

10. The method for preparing tris(4,7-biphenyl-1,10-o-phenanthroline) ruthenium dichloride according to claim 1, characterized in that, The molar ratio of hexafluorophosphate to tetraalkylammonium chloride or aryltrialkylammonium chloride to ruthenium trichloride hydrate is 2:2:1.

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