A highly luminescent star-shaped tetranuclear ruthenium complex and its preparation method and application

Abstract

The present invention discloses a highly luminescent star-shaped tetranuclear ruthenium complex and its preparation method and application, belonging to the technical field of synthesis methods of tetranuclear ruthenium complexes. The star-shaped tetranuclear ruthenium complex has the chemical formula [Ru(RuL)3]X4 or [Ru(LRu)3]X4, wherein X is a counter ion, and the counter ion is PF6 ‑ 、Cl ‑ 、ClO4 ‑ 、NO3 ‑ 、BF4 ‑ and CF3SO3 ‑ The present invention provides a method for preparing a highly luminescent star-shaped tetranuclear ruthenium complex. The prepared star-shaped tetranuclear ruthenium complex is dissolved in an acetonitrile solution, and the ultraviolet-visible absorption spectrum and fluorescence emission spectrum of the tetranuclear complex are measured to obtain the relative fluorescence quantum efficiency. The present invention assembles a novel tetranuclear metal Ru by bridging ligands. II The complex is a new type of luminescent material and can be used as a fluorescent probe.

Description

Technical Field

[0001] The present invention belongs to the technical field of synthesis methods of tetranuclear ruthenium complexes, and in particular relates to a strongly luminescent star-shaped tetranuclear ruthenium complex and a preparation method and application thereof. Background Art

[0002] Polypyridyl transition metal complexes such as ruthenium(II) complexes generally exhibit excellent photophysical chemistry, catalysis, and photochemical stability [Biancardo, M.; Bignozzi, C.; Doyle, H.; Redmond GAChem. Commun., 2005, 31, 3918] and therefore show potential in important applications such as molecular devices, dye-sensitized solar cells, and multichannel optical sensors and switches [Lee, CY; Farha, OK; Hong, BJ; Sarjeant, AA; Nguyen, ST; Hupp, JTJAm. Chem. Soc., 2011, 133, 15858].

[0003] Luminescent and redox-active polynuclear metal complexes have attracted considerable attention for both theoretical reasons and potential practical applications. For example, polynuclear metal complexes occupy a central position in the design of supramolecular systems capable of photoinduced energy transfer and / or charge separation, with the ultimate goal of building solar energy conversion and / or light-driven information processing devices. One major class of luminescent and redox-active polynuclear metal complexes is based on Ru(II)-polypyridine building blocks connected by electron-deficient (i.e., with relatively low-energy π* orbitals) bridging ligands. One of the most commonly used bridging ligands is the bis-chelating ligand 2,3-bis(2-pyridyl)pyrazine (2,3-dpp). A second class of luminescent polynuclear metal complexes is based on the same building blocks connected by anionic electron-rich (with relatively high-energy π orbitals) bridging ligands. An interesting distinction between these two classes of polynuclear systems is that electron-deficient bridging ligands can mediate metal-metal interactions via superexchange, primarily through electron transfer pathways using low-energy empty π* orbitals, while electron-rich ligands may utilize relatively high-energy filled π orbitals for hole transfer pathways. These heteropolynuclear metal complexes assembled with bridging ligands exhibit interesting photophysical and electrochemical properties by leveraging light-induced directivity, with energy and / or electron transfer processes occurring within the molecules [Sommovigo, M.; Denti, G.; Serroni, S.; Campagna, S.; Mingazzini, C.; Mariotti, C.; Juris, A. Inorg. Chem., 2001, 40, 3318.]. These complexes of different metal ions assembled with bridging ligands fully utilize the advantages of metal ions and enhance the photosensitivity of the molecules' light absorption.

[0004] Therefore, extensive efforts have been made to develop antenna systems that can utilize solar energy. However, no switching function has been introduced into such antenna systems. In recent years, the main reports on multinuclear ruthenium / osmium complexes related to energy transfer are mainly assembled through bridging ligands, such as RuIr3[Sabatini, C.; Barbieri, A.; Baregelletti, F.; Armb, KJ; Gareth Williams, JA Photochem. Photobiol. Sci., 2007, 6, 397], Ru3Os[Otsuki, J., Imai, A., Sato, K., Li, D.-M., Hosoda, M., Owa, M., Akasaka, T., Yoshikawa, I., Araki, K., Suenobu, T. and Fuku-zumi, S. Chem. Eur. J., 2008, 14, 2709], RuOs3 [Denti, G.; Serroni, S.; Campagna, S.; Ricevuto, V.; Balzani, V. Coord. Chem. Rev., 1991, 111, 227], Ru4 [Serroni, S.; Campagna, S.; Denti, G.; Keyes, T. E.; Vos, J. G. Inorg. Chem. 1996, 35, 4513] and RuOsRu [Paul, A.; Das, S.; Bar, M.; Baitalik, S. Dalton Trans., 2021, 50, 14872]. In the supramolecular system RuOs3 designed and synthesized by transition metal building blocks, the direction of energy transfer can be predetermined in advance. In 2008, Otsuki et al. reported the first example of a tetranuclear Ru₃Os complex with switchable antenna properties, in which the Os center acts as an energy-accepting site and the three Ru centers act as energy-absorbing sites. The on / off switching of energy harvesting depends on the redox state of the ligands connecting the center and the peripheral metal complex [Otsuki, J., Imai, A., Sato, K., Li, D.-M., Hosoda, M., Owa, M., Akasaka, T., Yoshikawa, I., Araki, K., Suenobu, T., and Fuku-zumi, S. Chem. Eur. J., 2008, 14, 2709].

[0005] Recently, a new heterometallic Ru II -Os IITrimers [Dai, W.; Yu, S.; Kong, C.; Zhao, D.; He, C.; Liu, Z.; Dong, J.; Liu, J.-J.; Cheng, F. Dalton Trans., 2023, 52, 990] and homotetranuclear ruthenium complexes [Yin, H. J., Yu, S. W., Yang, Y. T., He, C. X., Cheng, F. X. Inorg. Chem., 2024, 63, 621] exhibit strong absorption across the entire UV and visible regions. At room temperature and under visible light excitation, the luminescence of the multinuclear complexes is quantitatively quenched by intramolecular energy transfer. This electron and energy transfer process could provide a means for electronic communication between molecular entities in devices.

[0006] Therefore, new bridging ligands are explored to assemble new polynuclear metal Ru II Complexes and new luminescent materials with improved photophysical properties are still needed. Summary of the Invention

[0007] The purpose of the present invention is to provide a highly luminescent star-shaped tetranuclear ruthenium complex and its preparation method and application, so as to solve the problems existing in the above-mentioned prior art.

[0008] One of the technical solutions provided by the present invention:

[0009] A highly luminescent star-shaped tetranuclear ruthenium complex, wherein the chemical formula of the star-shaped tetranuclear ruthenium complex is [Ru(RuL)3]X4 or [Ru(LRu)3]X4, wherein X is a counterion, and the counterion is PF6 - 、Cl - 、ClO4 - 、NO3 - 、BF4 - and CF3SO3 - One of the following, L is a bridging ligand.

[0010] When the chemical formula of the star-shaped tetranuclear ruthenium complex is [Ru(RuL)3]X4, the chemical structural formula of its cation is:

[0011]

[0012] When the chemical formula of the star-shaped tetranuclear ruthenium complex is [Ru(LRu)3]X4, the chemical structural formula of its cation is:

[0013] The second technical solution provided by the present invention is:

[0014] The chemical formula of the star-shaped tetranuclear ruthenium complex is [Ru(RuL)3]X4, and the preparation method of the star-shaped tetranuclear ruthenium complex is:

[0015] S1. Under nitrogen protection, 4-methyl-2-2'-bipyridine-4'-benzaldehyde and Ru(bpy)2Cl2·2H2O are heated under reflux in ethanol to obtain a solid substance; the obtained solid substance is further heated to react with 1,10-phenanthrolinedione and ammonium acetate in acetic acid; after the reaction is completed, a salt containing a counterion is added to carry out a conversion reaction; and the mononuclear ruthenium complex RuL is separated and purified.

[0016] S2. heating a mononuclear ruthenium complex RuL and RuCl3 in an organic solvent to react; after the reaction is complete, removing the solvent to obtain a solid substance, adding a salt containing a counter ion to carry out a conversion reaction, and separating and purifying the obtained solid substance to obtain a star-shaped tetranuclear ruthenium complex [Ru(RuL)3]X4;

[0017] The counterion is PF6 - 、Cl - , ClO4 - , NO3 - , BF4 - and CF3SO3 - One of them.

[0018] Specifically, the reaction route is as follows:

[0019]

[0020] Preferably, in step S1, the mass ratio of 4-methyl-2-2'bipyridine-4'benzaldehyde to Ru(bpy)2Cl2·2H2O is 235:637; the temperature of the heating reflux reaction is 80°C and the time is 72h;

[0021] The mass ratio of 1,10-phenanthrolinedione to ammonium acetate is 233 mg:1.73 g; the heating reaction temperature is 130° C. and the time is 10 h;

[0022] In step S2, the mass ratio of the pure mononuclear ruthenium complex RuL to RuCl3 is 360:22, the temperature of the heating reaction is 140°C, and the time is 24 hours.

[0023] The chemical formula of the star-shaped tetranuclear ruthenium complex is [Ru(LRu)3]X4, and the preparation method of the star-shaped tetranuclear ruthenium complex is:

[0024] S1. Under nitrogen protection, 1,10-phenanthrolinedione and Ru(bpy)2Cl2·2H2O are heated under reflux in ethanol to obtain a solid substance; the obtained solid substance is further heated to react with 4-methyl-2-2'-bipyridine-4'-benzaldehyde and ammonium acetate in acetic acid; after the reaction is completed, a salt containing a counterion is added to carry out a conversion reaction; and the mononuclear ruthenium complex LRu is obtained by separation and purification;

[0025] S2. heating the mononuclear ruthenium complex LRu and RuCl3 in an organic solvent to react; after the reaction is complete, removing the solvent, adding a salt containing a counter ion to carry out a conversion reaction; separating and purifying the obtained solid material to obtain a star-shaped tetranuclear ruthenium complex [Ru(LRu)3]X4;

[0026] The counterion is PF6 - 、Cl - , ClO4 - , NO3 - , BF4 - and CF3SO3 - One of them.

[0027] Specifically, the reaction route is as follows:

[0028]

[0029] Preferably, in step S1, the mass ratio of 1,10-phenanthrolinedione to Ru(bpy)2Cl2·2H2O is 129:317, and the heating reflux reaction temperature is 80°C and the time is 12h;

[0030] The mass ratio of 4-methyl-2-2'bipyridine to ammonium acetate is 121:956, the heating reaction temperature is 130°C, and the time is 8 hours;

[0031] In step S2, the mass ratio of the mononuclear ruthenium complex LRu to RuCl3 is 360:22, the temperature of the heating reaction is 140°C, and the time is 24 hours.

[0032] The third technical solution provided by the present invention is:

[0033] Application of the above-mentioned strongly luminescent star-shaped tetranuclear ruthenium complex in the preparation of new luminescent materials.

[0034] The fourth technical solution provided by the present invention is:

[0035] The invention relates to an application of the above-mentioned strongly luminescent star-shaped tetranuclear ruthenium complex as a fluorescent probe.

[0036] Compared with the prior art, the present invention has the following advantages and technical effects:

[0037] The present invention provides a method for preparing a highly luminescent star-shaped tetranuclear ruthenium complex. The prepared star-shaped tetranuclear ruthenium complex is dissolved in an acetonitrile solution, and the ultraviolet-visible absorption spectrum and fluorescence emission spectrum of the tetranuclear complex are measured, and the relative fluorescence quantum efficiency is obtained by calculation. The present invention explores a novel bridging ligand to assemble a novel tetranuclear metal Ruthenium complex. II The complex is a new type of luminescent material and can be used as a fluorescent probe. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 Schematic diagram of the structure of the star-shaped tetranuclear ruthenium complex Ru(RuL)3 prepared in Example 1;

[0040] Figure 2 Schematic diagram of the structure of the star-shaped tetranuclear ruthenium complex Ru(LRu)3 prepared in Example 2;

[0041] Figure 3 The synthetic route of the star-shaped tetranuclear ruthenium complex Ru(RuL)3 in the present invention is shown in FIG.

[0042] Figure 4 The synthetic route of the star-shaped tetranuclear ruthenium complex Ru(LRu)3 in the present invention is shown in FIG.

[0043] Figure 5 The UV absorption spectra of the star-shaped tetranuclear ruthenium complexes prepared in Examples 1 and 2;

[0044] Figure 6 The fluorescence emission spectra of the star-shaped tetranuclear ruthenium complexes prepared in Examples 1 and 2 are shown. DETAILED DESCRIPTION

[0045] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0046] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0047] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0048] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the present invention. The present description and examples are intended to be illustrative only.

[0049] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0050] The room temperature in the present invention refers to 25±2°C.

[0051] The counter ion in the present invention can be PF6 - 、Cl - , ClO4 - , NO3 - , BF4 - and CF3SO3 - The following examples are typical but non-limiting examples of the preparation of a highly luminescent star-shaped tetranuclear ruthenium complex using a saturated ammonium hexafluorophosphate solution as a saturated counter salt solution.

[0052] Example 1

[0053] Under nitrogen protection, 235 mg of 4-methyl-2-2'bipyridine-4'benzaldehyde and 637 mg of Ru(bpy)2Cl2·2H2O were heated under reflux in ethanol solvent for 72 h. After cooling, the solvent was removed by rotary evaporation. The crude product was dissolved in 23 mL of glacial acetic acid and filtered. 233 mg of 1,10-phenanthrolinedione and 1.73 g of ammonium acetate were added. The mixture was heated at 130 ° C for about 10 h. After the reaction was completed, it was cooled to room temperature and 200 mL of water was added to dilute the mixture. The crude product was separated and purified twice by silica gel column chromatography using acetonitrile / ethanol = 1:1 and acetonitrile / water / saturated potassium nitrate solution = 100:5:3 as eluents. The orange-yellow ribbon solution was collected and the solvent was removed by distillation under reduced pressure. The resulting solid was dissolved in water, and saturated ammonium hexafluorophosphate solution was added to precipitate. The precipitate was recrystallized from acetonitrile / ether to obtain the mononuclear ruthenium complex LRu.

[0054] 360 mg of the mononuclear ruthenium complex RuL and 22 mg of RuCl3 were heated to 140°C in 200 mL of ethylene glycol solvent under nitrogen for 24 hours. After the reaction, the reaction mixture was freed of the solvent by rotary evaporation to obtain a solid. The solid was separated and purified by silica gel column chromatography using acetonitrile / water / saturated potassium nitrate solution in volume ratios of 100:5:3 and 8:3:1 as eluents. The orange-yellow colored solution was collected and the solvent was removed by vacuum distillation. The resulting solid was dissolved in water and then added with saturated ammonium hexafluorophosphate solution to precipitate. The precipitate was recrystallized from acetonitrile / ether to obtain 142 mg of pure tetranuclear ruthenium complex Ru(RuL)3 with a yield of 36.4%.

[0055] H NMR (400 MHz, [D6]DMSO): δ = 2.60 (s, 9H), 7.41 (d, J = 6.0 Hz, 3H), 7.53-7.60 (m, 15H), 7.68-7.71 (t, 9H), 7.77 (dd, J = 10.4, 5.6 Hz, 6H), 7.82 (t, J = 6.0 Hz, 3H), 7.87 (s, 6H ), 7.93 (d, J = 5.2 Hz, 3H), 8.16-8.22 (m, 12H), 8.29 (d, J = 5.6 Hz, 3H), 8.85-8.87 (d, 15H), 8.94 (d, J = 7.6 Hz, 6H), 9.40 (s, 3H). HR-ESI-MS: calculated value, m / z = 555.0770 (M-6PF6-Na) 5+ ,435.7368(M-7PF6-K) 6+ ; Exp. value, m / z = 555.3187 (M-6PF6-Na) 5+,434.4354(M-7PF6-K) 6+ .

[0056] Figure 1 Schematic diagram of the structure of the star-shaped tetranuclear ruthenium complex Ru(RuL)3 prepared in Example 1.

[0057] Figure 3 The synthetic route of the star-shaped tetranuclear ruthenium complex Ru(RuL)3 in the present invention is shown.

[0058] Example 2

[0059] Under nitrogen, 129 mg of 1,10-phenanthrolinedione and 317 mg of Ru(bpy)2Cl2·2H2O were heated under reflux in 200 mL of ethanol for 12 hours. After cooling, the solvent was removed by rotary evaporation. The solid was dissolved in 13 mL of glacial acetic acid and filtered. 121 mg of 4-methyl-2-2'-bipyridine and 956 mg of ammonium acetate were added to the filtrate, and the mixture was heated at 130°C for 8 hours. After the reaction, the solvent was removed, and the solid was isolated and purified using acetonitrile / ethanol (1:1) and acetonitrile / water / saturated potassium nitrate solution (100:5:3) as eluents. The orange-yellow colored solution was collected and the solvent removed by vacuum distillation. The resulting solid was dissolved in water and precipitated by adding saturated ammonium hexafluorophosphate solution. The precipitate was recrystallized from acetonitrile / ether to obtain the mononuclear ruthenium complex LRu.

[0060] 360 mg of the mononuclear ruthenium complex LRu and 22 mg of RuCl3 were heated to 140°C in 200 mL of ethylene glycol under nitrogen for 24 hours. After the reaction, the reaction mixture was freed of the solvent by rotary evaporation to obtain a crude product. The product was separated and purified by silica gel column chromatography using acetonitrile / water / saturated potassium nitrate solution in volume ratios of 100:5:3 and 8:3:1, respectively. The orange-yellow colored solution was collected and the solvent removed by vacuum distillation. The resulting solid was dissolved in water and saturated ammonium hexafluorophosphate solution was added to precipitate. The precipitate was recrystallized from acetonitrile / ether to obtain 118 mg of pure tetranuclear ruthenium complex Ru(LRu)3, with a yield of 30.3%.

[0061] 1H NMR (400MHz, [D6]CH3CN): δ = 2.67 (s, 9H), 7.22 (t, J = 6.4Hz, 6H), 7.39 (s, 3H), 7.45 (m, 6H), 7.60 ( s,6H),7.78-7.80(m,3H),7.84(d,J=4.8Hz,6H),7.90(m,3H),7.98-8.03(m,9H),8.11(q,J1=15.6 Hz, J2=8.0 Hz, 9H), 8.19 (t, J=5.6 Hz, 6H), 8.25-8.28 (m, 3H), 8.53 (dd, J1=16.0 Hz, J2=8.0 Hz, 12H), 8.80 (s, 3H), 9.02 (d, J=4.0 Hz, 6H), 9.37 (s, 3H). HR-ESI-MS: calculated, m / z=455.6043 (M-4PF6+2K+Na) 7+ ,359.5390(M-6PF6+2K) 8+ ; Exp. value, m / z = 455.1024 (M-4PF6+2K+Na) 7+ ,360.3240(M-6PF6+2K) 8+ .

[0062] Figure 2 This is a schematic structural diagram of the star-shaped tetranuclear ruthenium complex Ru(LRu)3 prepared in Example 2.

[0063] Figure 4 The synthetic route of the star-shaped tetranuclear ruthenium complex Ru(LRu)3 in the present invention is shown.

[0064] The tetranuclear ruthenium complex prepared in Examples 1 and 2 was dissolved in an acetonitrile solution to investigate its luminescence properties. The luminescence property data of the tetranuclear ruthenium complex was obtained by measuring the ultraviolet-visible absorption spectrum, fluorescence emission spectrum, and lifetime.

[0065] The specific steps are: adding the star-shaped tetranuclear ruthenium complexes prepared in Examples 1 and 2 of the present invention to the acetonitrile solvent respectively to make the molar concentration of the complexes 10 -5 M, measure the UV-visible absorption spectrum and fluorescence emission spectrum of the above complex solution to obtain luminescence data.

[0066] The UV-visible absorption spectra of the star-shaped tetraruthenium complexes prepared in Examples 1 and 2 of the present invention in acetonitrile solution are as follows: Figure 5 As shown: The high energy absorption band of 287-290nm and the absorption band of 336-387nm are caused by the π-π *The absorption peaks at 472nm and 498nm in the tetranuclear ruthenium complex are attributed to the charge transition from metal ruthenium to ligand L / bpy {Ru(dπ)→bpy(π * ),Ru(dπ)→L(π * )} absorption peaks, the tetranuclear ruthenium complex exhibits strong absorption in the entire ultraviolet-visible light region and is a good visible light absorption antenna.

[0067] The fluorescence emission spectra of the star-shaped tetranuclear ruthenium complexes prepared in Examples 1 and 2 of the present invention in acetonitrile solution are as follows: Figure 6 As shown: The tetranuclear ruthenium complex Ru(RuL)3 exhibits a maximum emission peak at 626nm, while the maximum emission peak of Ru(LRu)3 red-shifts to 672nm, which is attributed to the metal-ligand transition. 3 The triplet transition of MLCT(Ru→bpy / L). 2+ As the reference substance, the luminescence quantum efficiency in acetonitrile solvent is 6%. The relative quantum efficiencies of the tetranuclear complexes Ru(RuL)3 and Ru(LRu)3 are calculated by the following formula to be 2.54% and 1.07%, respectively.

[0068] φ s = φ std (A std / A s ) (I s / I std ) (η s / η std ) 2 (1)

[0069] Wherein, the subscripts s and std represent the substance to be tested and the standard substance, respectively, s is the luminescence quantum efficiency, A is the absorbance at the excitation wavelength, I is the integrated intensity of the emission peak, and η is the refractive index of the solution. 2+ As the reference substance, the fluorescence quantum efficiency of its acetonitrile solution is φ std =0.06, when std and s are known, by measuring the absorbance A of the test system and the standard substance at the excitation wavelength s 、A std and fluorescence intensity I s , I std , the fluorescence quantum efficiency φ can be calculated s .

[0070] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A star-shaped tetranuclear ruthenium complex, characterized in that The star-shaped tetranuclear ruthenium complex has the general chemical formula [Ru(RuL)3]X4, and the chemical structural formula of its cation is: ； The star-shaped tetranuclear ruthenium complex has the general chemical formula [Ru(LRu)3]X4, and the chemical structural formula of its cation is: ; Wherein X is a counter ion, and the counter ion is PF6 - 、Cl - , ClO4 - , NO3 - , BF4 - and CF3SO3 - One of the following; L is a bridging ligand.

2. A method for preparing a star-shaped tetranuclear ruthenium complex according to claim 1, characterized in that: When the chemical formula of the star-shaped tetranuclear ruthenium complex is [Ru(RuL)3]X4, the steps are: S1. Under nitrogen protection, 4-methyl-2-2'-bipyridine-4'-benzaldehyde and Ru(bpy)2Cl2·2H2O are heated under reflux in ethanol to obtain a solid substance; the obtained solid substance is further heated to react with 1,10-phenanthrolinedione and ammonium acetate in acetic acid; after the reaction is completed, a salt containing a counterion is added to carry out a conversion reaction; and the mononuclear ruthenium complex RuL is separated and purified. S2. heating the mononuclear ruthenium complex RuL and RuCl3 in an organic solvent to react; after the reaction is complete, removing the solvent, adding a salt containing a counter ion to carry out a conversion reaction, and separating and purifying the obtained solid material to obtain a star-shaped tetranuclear ruthenium complex [Ru(RuL)3]X4; The counterion is PF6 - 、Cl - , ClO4 - , NO3 - , BF4 - and CF3SO3 - One of them.

3. The preparation method according to claim 2, characterized in that In step S1, the mass ratio of 4-methyl-2-2'bipyridine-4'benzaldehyde to Ru(bpy)2Cl2·2H2O is 235:637; the heating reflux reaction temperature is 80°C and the time is 72 hours; The mass ratio of 1,10-phenanthrolinedione to ammonium acetate is 233 mg:1.73 g; the heating reaction temperature is 130° C. and the time is 10 h; In step S2, the mass ratio of the pure mononuclear ruthenium complex RuL to RuCl3 is 360:22, the temperature of the heating reaction is 140°C, and the time is 24 hours.

4. A method for preparing a star-shaped tetranuclear ruthenium complex according to claim 1, characterized in that: When the chemical formula of the star-shaped tetranuclear ruthenium complex is [Ru(LRu)3]X4, the steps are: S1. Under nitrogen protection, 1,10-phenanthrolinedione and Ru(bpy)2Cl2·2H2O are heated under reflux in ethanol to obtain a solid substance; the obtained solid substance is further heated to react with 4-methyl-2-2'-bipyridine-4'-benzaldehyde and ammonium acetate in acetic acid; after the reaction is completed, a salt containing a counterion is added to carry out a conversion reaction; and the mononuclear ruthenium complex LRu is obtained by separation and purification; S2. heating the mononuclear ruthenium complex LRu and RuCl3 in an organic solvent to react; after the reaction is complete, removing the solvent, adding a salt containing a counter ion to carry out a conversion reaction; separating and purifying the obtained solid material to obtain a star-shaped tetranuclear ruthenium complex [Ru(LRu)3]X4; The counterion is PF6 - 、Cl - , ClO4 - , NO3 - , BF4 - and CF3SO3 - One of them.

5. The preparation method according to claim 4, characterized in that In step S1, the mass ratio of 1,10-phenanthrolinedione to Ru(bpy)2Cl2·2H2O is 129:317, and the heating reflux temperature is 80°C for 12 hours; The mass ratio of 4-methyl-2-2'bipyridine to ammonium acetate is 121:956, the heating reaction temperature is 130°C, and the time is 8 hours; In step S2, the mass ratio of the mononuclear ruthenium complex LRu to RuCl3 is 360:22, the temperature of the heating reaction is 140°C, and the time is 24 hours.

6. Use of the star-shaped tetranuclear ruthenium complex according to claim 1 in preparing a luminescent material.

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