A terpyridine zinc complex, a preparation method and application thereof

Abstract

The application discloses a terpyridine zinc complex and a preparation method and application thereof. The terpyridine zinc complex takes transition metal zinc as a central metal ion and takes terpyridine as a polydentate ligand. The terpyridine zinc complex can emit red light and near-infrared light under the excitation of ultraviolet visible light in an aggregated state, can be used as a luminescent material, and can generate active oxygen substances such as singlet oxygen and hydroxyl radicals under the condition of sunlight irradiation, and has good photosensitivity and can be used as a photosensitizer.

Description

Technical Field

[0001] This invention relates to a zinc complex, specifically a terpyridine zinc complex, and also to its synthesis method and its application as a photosensitizer or luminescent material, belonging to the field of optical materials. Background Technology

[0002] Photosensitive materials with triplet states have wide applications in photodynamic therapy, cell imaging, antibacterial applications, light-emitting devices, and encryption materials due to their ability to generate reactive oxygen species. Normal organic light-emitting materials struggle to achieve triplet emission because intersystem crossing from the singlet to the triplet excited state is difficult. Common methods to achieve triplet emission include introducing heavy atoms or realizing n-Π* to increase spin-orbit coupling and enhance intersystem crossing. Alternatively, frontier-orbit separation can be achieved, reducing the energy difference between the excited triplet and singlet states and facilitating intersystem crossing.

[0003] In traditional metal-organic luminescent materials, most materials use precious metals such as platinum, gold, and iridium as coordinating metals (Mitra K, Lyons CE, Hartman MC TA Platinum(II) Complex of Heptamethine Cyanine for Photoenhanced Cytotoxicity and Cellular Imaging in Near-IR Light[J]. Angew Chem Int Ed Engl, 2018, 57(32):10263-10267) because they promote phosphorescence by overcoming the forbidden transition coupling of triplet excitons through strong spin orbitals. However, this leads to problems such as high material costs and environmental pollution. At the same time, if the complexes formed by these metals are used for photodynamic therapy or cell imaging, they also face the problem of poor solubility. Therefore, it is of great significance to synthesize photosensitizers or luminescent materials with non-precious metals as coordinating cores in a simple and low-cost manner. Summary of the Invention

[0004] To address the technical problems existing in the prior art, the first objective of this invention is to provide a zinc terpyridine complex that has aggregation-induced emission properties, emits red light under ultraviolet excitation, and generates reactive oxygen species such as singlet oxygen and hydroxyl radicals under sunlight.

[0005] The second objective of this invention is to provide a method for preparing zinc terpyridine complexes that is simple to operate and has low cost.

[0006] The third objective of this invention is to provide the application of the zinc terpyridine complex as a photosensitizer or luminescent material. This zinc terpyridine complex can emit red fluorescence at 620 nm under ultraviolet-visible light excitation and has aggregation-induced luminescence properties in solution. At the same time, under sunlight irradiation, the highly aggregated state in solution can generate reactive oxygen species, which can be widely used as a photosensitizer or luminescent material.

[0007] To achieve the above technical objectives, the present invention provides a terpyridine zinc complex having the structure of Formula 1:

[0008]

[0009] in,

[0010] X is the equilibrium anion;

[0011] R1 is a nitrogen heterocyclic unit, a diazaheterocyclic unit, a benzo[a]azaheterocyclic unit, or a benzo[a]diazaheterocyclic unit; R2 has the following structural units:

[0012]

[0013] Y represents a heteroatom;

[0014] R3 is a C1 to C5 alkyl group or a hydrogen atom.

[0015] The terpyridine zinc complex of this invention uses zinc as the central metal ion and terpyridines as polydentate ligands. The terpyridines can form stable terpyridine zinc complexes with octahedral structures with zinc ions. Furthermore, the terpyridine ligands in the terpyridine zinc complex incorporate triphenylamine groups and nitrogen-containing heterocyclic groups with high electron-donating capabilities. Terpyridine itself has a strong electron-withdrawing ability, and the strong electron-donating ability of the triphenylamine and nitrogen-containing heterocyclic groups further enhances the electron push-pull effect and special charge transfer, enabling the terpyridine zinc complex to emit red light under ultraviolet excitation. The triphenylamine group, due to its rotatable nature, imparts aggregation-induced emission properties, exhibiting red light emission in its aggregated state in solution. Simultaneously, under sunlight irradiation, the terpyridine zinc complex can generate singlet oxygen and hydroxyl radicals, exhibiting good photosensitivity.

[0016] As a preferred embodiment, X in the zinc terpyridine complex of Formula 1 is PF6. - R1 is Y is an oxygen, sulfur, or nitrogen atom; R3 is a methyl group. R1 is preferably a nitrogen-containing heterocyclic unit such as a pyridine unit, pyrazine unit, or pyrimidine unit, which can effectively regulate the energy level of the electron acceptor unit. X is preferably PF6. - Compared to NO3- Other anions can better characterize the structure (e.g., NMR, mass spectrometry analysis), and also improve the solubility of zinc terpyridine complexes.

[0017] The terpyridine zinc complexes of the present invention have several typical structures, as exemplified below:

[0018]

[0019]

[0020] This invention also provides a method for preparing a zinc terpyridine complex, comprising the following steps:

[0021] 1) 2-Bromo-6-acetylpyridine was reacted with an aldehyde compound of formula 2 and ammonia via a Michael addition-ring-closing reaction to obtain a dibromo-terpyridine compound of formula 3;

[0022] 2) By coupling a dibromo-terpyridine compound with a borate compound of formula 4, a terpyridine ligand of formula 5 is obtained;

[0023] 3) After the tripyridine ligand undergoes a coordination reaction with the zinc salt, an anion substitution reaction is carried out to obtain the product;

[0024]

[0025]

[0026] R1 is a nitrogen heterocyclic unit, a diaza heterocyclic unit, a benzodiazepine heterocyclic unit, or a benzodiazepine heterocyclic unit;

[0027] R2 has the following structural units:

[0028]

[0029] Y represents a heteroatom;

[0030] R3 is a C1 to C5 alkyl group or a hydrogen atom.

[0031] As a preferred approach, 2-bromo-6-acetylpyridine undergoes a Michael addition reaction with an aldehyde compound of formula 2 in the presence of a base, followed by the addition of ammonia to initiate a ring-closure reaction. The theoretical reaction ratio of 2-bromo-6-acetylpyridine to the aldehyde compound is 2:1. A suitable excess of 6-bromo-2-acetylpyridine is beneficial for increasing the yield of the target product. Generally, the molar ratio of 2-bromo-6-acetylpyridine to the aldehyde compound of formula 2 is 2–2.5:1, with 2.4:1 being the most preferred. Sodium hydroxide is typically used as the base, primarily to promote the ring-closure reaction of the Michael addition intermediate. The molar ratio of sodium hydroxide to the aldehyde compound of formula 2 is 3–5:1.

[0032] As a preferred embodiment, the Michael addition reaction is performed under the following conditions: at room temperature, for 6 to 10 hours.

[0033] As a preferred embodiment, the closed-loop reaction is carried out at a temperature of 70–90°C for 16–32 hours. The preferred reaction temperature is 75–85°C.

[0034] As a preferred embodiment, a dibromoterpyridine compound and a borate of formula 4 undergo a coupling reaction in the presence of a base under the catalysis of tetrakis(triphenylphosphine)palladium(0). The molar ratio of the dibromoterpyridine compound to the borate of formula 4 is 1:2.5–4. The base is sodium hydroxide, which is added in the form of a 1 mol aqueous solution. The molar ratio of the dibromoterpyridine compound to the aqueous sodium hydroxide solution is 1:6–8. The molar ratio of tetrakis(triphenylphosphine)palladium(0) to the dibromoterpyridine compound is 0.06–0.2:1.

[0035] As a preferred embodiment, the coupling reaction is performed at a temperature of 75–85°C for 30–60 hours.

[0036] As a preferred embodiment, the coordination reaction is carried out at 60–70°C for 18–32 hours. The molar ratio of the terpyridine ligand to the zinc salt is 2:1.

[0037] As a preferred embodiment, the anion substitution reaction uses ammonium hexafluorophosphate as the hexafluorophosphate anion source. The molar ratio of ammonium hexafluorophosphate to zinc salt is 10–20:1. The zinc salt is a readily soluble zinc salt, such as zinc nitrate.

[0038] This invention also provides an application of the zinc terpyridine complex, which can be used as a photosensitizer or as a luminescent material in light-emitting devices. The zinc terpyridine complex exhibits red light emission at 620 nm under 350 nm ultraviolet excitation, and also possesses aggregation-induced emission properties in solution, emitting red light in the aggregated state. Therefore, it can be used as a fluorescent material in light-emitting devices. Furthermore, under sunlight irradiation, the zinc terpyridine complex can generate reactive oxygen species such as singlet oxygen and hydroxyl radicals, exhibiting good photosensitivity and thus can be widely used as a photosensitive material.

[0039] Compared with existing technologies, the beneficial technical effects of the present invention are as follows:

[0040] The terpyridine zinc complex provided by this invention uses zinc as the central metal ion. Zinc is a transition metal in the first period, which is cheaper than platinum, gold and iridium and has less environmental pollution.

[0041] The zinc terpyridine complex provided by this invention emits red light under ultraviolet light excitation and exhibits aggregation-induced luminescence in a mixed solution of acetonitrile and water, and can be used as a luminescent material.

[0042] The zinc terpyridine complex provided by this invention can generate reactive oxygen species such as singlet oxygen and hydroxyl radicals under sunlight irradiation, exhibiting good photosensitivity.

[0043] The preparation method of the zinc terpyridine complex provided by this invention is simple in operation and low in cost, which is conducive to large-scale production. Attached Figure Description

[0044] Figure 1 The single-crystal diffraction pattern of complex 7.

[0045] Figure 2 The UV absorption spectrum and liquid fluorescence spectrum of complex 7 were measured by increasing the content of the undesirable solvent water and α-methyl-2 ...

[0046] Figure 3 The UV absorption and liquid fluorescence spectra of complexes 8 and 9 were measured by placing them in acetonitrile solution with an increased content of the undesirable solvent water.

[0047] Figure 4 Photographs of complex 7 under sunlight and under 350nm ultraviolet fluorescent light.

[0048] Figure 5 Normalized fluorescence spectra of compounds 4–6 and complexes 7–9 in solid form.

[0049] Figure 6 Electron paramagnetic spectra of solid complexes 7–9.

[0050] Figure 7 The ultraviolet absorption spectrum of 9,10-anthrayl-bis(methylene)dimalonic acid, a singlet oxygen indicator for the degradation of complex 7.

[0051] Figure 8 The UV absorption spectrum of 9,10-anthrayl-bis(methylene)dimalonic acid, a singlet oxygen indicator for the degradation of complex 8.

[0052] Figure 9 A comparison graph showing the rate at which complexes 7 and 8 degrade the singlet oxygen indicator 9,10-anthrayl-bis(methylene)dimalonic acid with the commercial photosensitizer methylene blue. Detailed Implementation

[0053] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0054] The substrates and solvents used in the following examples are all commercially available products (analytical grade reagents). All reagents used have undergone purification, drying, and deoxygenation pretreatment. The synthesis and processing procedures involved use standard anhydrous and oxygen-free techniques.

[0055] 1 ¹H NMR (400MHz) was performed using CDCl₃ and CD₃CN as solvents and TMS as an internal standard.

[0056] Multiplicity is defined as follows: s (singleton); d (doublet); t (triplet); q (quartet); and m (multiplet). Absorption intensity is defined as follows.

[0057] Unless otherwise specified, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not necessarily within the scope of this invention.

[0058] Example 1

[0059] Preparation of compound 1:

[0060] Target product:

[0061] Accurately pipette 1.112 g of 4-pyridinecarboxaldehyde (1 mL), then add 4.8 g of 6-bromo-2-acetylpyridine to a 250 mL flask, followed by 60 mL of ethanol and sonication for 5 minutes. After sonication, add a stir bar in an ice bath, then add 2 g of sodium hydroxide to the flask, and stir at room temperature for 8 hours to stop the reaction. Scrape off the solid adhering to the flask wall using sonication, and then add 25 mL of 25% ammonia solution while stirring at room temperature. Raise the temperature to 80°C and reflux overnight with a condenser. The reaction ends the next day. After cooling to room temperature, filter to obtain a yellow solid. Wash the solid three times with methanol, scrape it off and place it in a flask, add 50 mL of methanol, and sonicate for 5 minutes. After sonication, reflux at 85°C for 10 minutes, cool to room temperature, and filter to obtain a yellow solid. Place the solid in a vacuum desiccator and dry to obtain 1.99 g of a white solid, with a yield of 41.7%.

[0062] 1 H NMR (400MHz, CDCl3, ppm): δ = 8.81 (d, J = 6.4Hz, 2H,), 8.72 (s, 2H), 8.60 (d, J = 7.6Hz, 2H), 7.75 (m, 4H), 7.56 (d, J = 7.6Hz, 2H);

[0063] 13C NMR (126MHz, CDCl3, ppm): δ = 156.7, 154.9, 150.6, 148.0, 145.6, 141.7, 139.2, 128.5, 121.7, 119.6.

[0064] Preparation of compound 2:

[0065] Target product:

[0066] Accurately weigh 1 g of 5-pyrimidinecarboxaldehyde and 4.56 g of 6-bromo-2-acetylpyridine into a 250 mL flask. Add 60 mL of ethanol and sonicate for 5 minutes to dissolve. After sonication, add a stir bar in an ice bath, then add 1.8 g of sodium hydroxide into the flask. Stir at room temperature for 8 hours and then stop the reaction. Scrape off the solid adhering to the flask wall with sonication. Then, while stirring at room temperature, add 25 mL of 25% ammonia solution. Raise the temperature to 80 °C and reflux overnight with a condenser. The reaction ends the next day. After cooling to room temperature, filter to obtain a yellow solid. Wash the solid three times with methanol, scrape it off and place it in a flask. Add 50 mL of methanol and sonicate for 5 minutes. After sonication, reflux at 85 °C for 10 minutes. After cooling to room temperature, filter to obtain a yellow solid. Place the solid in a vacuum desiccator and dry to obtain 1.72 g of a brown solid. The yield is 41.8%.

[0067] 1 H NMR (400MHz, CDCl3, ppm): δ = 8.81 (d, J = 6.4Hz, 2H,), 8.72 (s, 2H), 8.60 (d, J = 7.6Hz, 2H), 7.75 (m, 4H), 7.56 (d, J = 7.6Hz, 2H).

[0068] 13 C NMR (126MHz, CDCl3, ppm): δ = 156.7, 154.9, 150.6, 148.0, 145.6, 141.7, 139.2, 128.5, 121.7, 119.6.

[0069] Synthesis of compound 3:

[0070] Target product:

[0071] Accurately weigh 1g of pyrazine-2-carboxaldehyde and 4.78g of 6-bromo-2-acetylpyridine into a 250mL flask. Add 60mL of ethanol and sonicate for five minutes to dissolve. After sonication, add a stir bar in an ice bath, then add 1.9g of sodium hydroxide into the flask. Stir at room temperature for 8 hours and then stop the reaction. Scrape off the solid adhering to the flask wall with sonication, and then add 25mL of 25% ammonia solution with stirring at room temperature. Raise the temperature to 80℃ and reflux overnight with a condenser. The reaction ends the next day. After cooling to room temperature, filter to obtain a yellow solid. Wash the solid three times with methanol, scrape it off and place it in a flask. Add 50mL of methanol and sonicate for 5 minutes. After sonication, reflux at 85℃ for 10 minutes. After cooling to room temperature, filter to obtain a yellow solid. Place the solid in a vacuum desiccator and dry to obtain 1.55g of a pale yellow solid. The yield is 35.7%.

[0072] 1 H NMR (400MHz, CDCl3, ppm): δ = 9.33 (d, J = 1.6Hz, 1H), 9.04 (s, 2H), 8.78 (t, J = 4Hz, H), 8.6 8(d,J=2.4Hz,H), 8.58(t,J=8.4Hz,2H), 7.73(t,J=15.2Hz,2H), 7.55(d,J=8.4Hz,2H).

[0073] 13 C NMR (126MHz, CDCl3, ppm): δ = 156.7, 154.9, 150.3, 144..5, 142.8, 141.7, 139.2, 128.5, 119.9, 119.2.

[0074] Synthesis of compound 4:

[0075] Target product:

[0076] Compound 1 (0.19 g, 0.4 mmol) and triphenylamine 4-borate (470 mg, 1.3 mmol) were added to a 250 mL flask, followed by the addition of 36 mL of tetrahydrofuran, which was dissolved by sonication. After complete dissolution, 2.5 mL of an aqueous solution of sodium hydroxide (1 mol / L) was added. Finally, a stir bar and tetra(triphenylphosphine)palladium(0) (0.11 g, 0.087 mmol) were added. The mixture was purged under vacuum with nitrogen three times at room temperature and reacted at 83 °C for 2 days. After cooling to room temperature, the tetrahydrofuran was evaporated to dryness, and the mixture was washed with 50 mL of methanol by sonication for 5 minutes. The resulting gray solid was then purified by neutral alumina column chromatography using dichloromethane as the developing solvent. Pure dichloromethane was used as the developing solvent to give a white compound, which was dried to give 0.14 g of the target product (51% yield).

[0077] 1 H NMR (400MHz, CDCl3, ppm): δ = 8.90 (s, 2H), 8.79 (d, J = 6Hz, 2H), 8.61 (d, J = 7.6Hz, 2H), 8.07 (d, J =4Hz,4H),7.94(t,J=8Hz,4H),7.77(m,4H),7.30(m,8H),7.20(m,12H),7.07(t,J=7.2Hz,4H).

[0078] 13 C NMR (126MHz, CDCl3, ppm): δ = 156.5, 156.1, 155.2, 150.6, 148.9, 147.5, 147.2, 146. 4,137.6,132.7,129.4,127.8,124.9,123.4,123.0,121.7,120.0,119.06,118.71.

[0079] ESI-MS (796.33 calcd. For C 56 H 40 N6):m\z 797.3392[L+H] 1+ (calcd m / z:797.3392).

[0080] Synthesis of compound 5:

[0081] Target product:

[0082] Compound 2 (0.43 g, 0.92 mmol) and triphenylamine 4-borate (979 mg, 2.8 mmol) were added to a 250 mL flask, followed by the addition of 36 mL of tetrahydrofuran, which was dissolved by sonication. After complete dissolution, 2.5 mL of an aqueous solution of sodium hydroxide (1 mol / L) was added. Finally, a stir bar and tetra(triphenylphosphine)palladium (0) (0.2 g, 0.18 mmol) were added. The mixture was purged under vacuum with nitrogen three times at room temperature and reacted at 83 °C for 2 days. After cooling to room temperature, the tetrahydrofuran was evaporated to dryness, and the mixture was washed with 50 mL of methanol by sonication for 5 minutes. The resulting gray solid was then purified by neutral alumina column chromatography after dissolving it in dichloromethane. The developing solvent was pure dichloromethane, which yielded a white compound. After drying, 0.57 g of the target product was obtained (77% yield).

[0083] 1 H NMR (400MHz, CDCl3, ppm): δ = 9.32 (s, 1H), 9.24 (s, 2H), 8.90 (s, 2H), 8.61 (d, J = 7.2Hz, 2H), 8.05 (d, J = 8 .4Hz,4H),7.94(t,J=16Hz,2H),7.78(d,J=2Hz,2H),7.30(m,8H),7.19(m,12H).7.07(t,J=14.8Hz,4H).

[0084] 13 C NMR (126MHz, CDCl3, ppm): δ=158.7,156.7,156.2,155.2,154.9,149.0,147 .4,143.4,137.7,132.5,129.4,127.7,124.9,122.9,120.1,118.9,118.5.

[0085] ESI-MS (798.33 calcd. For C 55 H 39 N6):m\z 797.3333[L+H] 1+ (calcd m / z:798.3345).

[0086] Synthesis of compound 6:

[0087] Target product:

[0088] Compound 3 (0.41 g, 0.88 mmol) and triphenylamine 4-borate (1037 mg, 2.9 mmol) were added to a 250 mL flask, followed by the addition of 36 mL of tetrahydrofuran, which was dissolved by sonication. After complete dissolution, 2.5 mL of an aqueous solution of sodium hydroxide (1 mol / L) was added. Finally, a stir bar and tetra(triphenylphosphine)palladium(0) (0.21 g, 0.18 mmol) were added. The mixture was purged under vacuum with nitrogen three times at room temperature and reacted at 83 °C for 2 days. After cooling to room temperature, the tetrahydrofuran was evaporated to dryness, and the mixture was washed with 50 mL of methanol by sonication for 5 minutes. The resulting gray solid was then purified by neutral alumina column chromatography using dichloromethane as the developing solvent. Pure dichloromethane was used as the developing solvent to obtain a white compound, which was dried to give 0.56 g of the target product (76% yield).

[0089] 1 H NMR (400MHz, CDCl3, ppm): δ = 9.34 (d, J = 1.6Hz, 1H), 9.25 (s, 2H), 8.78 (t, J = 4Hz, H), 8.64 (d, J = 2.4Hz, H), 8.60 (d, J = 7.6Hz, 2 H), 8.09 (d, J = 8.8Hz, 4H), 7.93 (t, J = 15.6Hz, 2H), 7.77 (d, J = 7.2Hz, 2H), 7.30 (m, 8H), 7.19 (m, 12H), 7.07 (t, J = 14.8Hz, 4H).

[0090] 13 C NMR (126MHz, CDCl3, ppm): δ = 156.6, 156.1, 155.3, 151.1, 148.8, 147.5, 144.4, 142.8,137.5,132.8,129.4,127.8,124.8,123.3,123.1,119.9,119.0,118.4. ESI-MS(797.33calcd.For C 56 H 40 N6):m\z 798.3332[L+H] 1+ (calcd m / z:798.3345).

[0091] Preparation of complex 7:

[0092] Target product:

[0093] The ligand (compound 4) (64.62 mg, 81.08 μmol) was accurately weighed using a four-digit balance and dissolved in 20 mL of chloroform. Then, 20 mL of analytical grade methanol was added. A methanol solution of zinc nitrate hexahydrate (12.06 mg, 40.05 μmol) was accurately pipetted into the solution, and then added to the mixture containing the dissolved ligand while stirring. The mixture was incubated overnight at 65 °C. After the reaction was complete and cooled to room temperature, 10 equivalents of ammonium hexafluorophosphate (NH4PF6) were weighed and added to the mixture. After addition to the reaction system, the mixture was dissolved by sonication to obtain a red flocculent. The mixture was stirred for 1 hour until complete displacement of the flocculent. 50 mg of a red solid was obtained by funnel filtration, with a yield of 92%. The red solid product was analyzed by 1H NMR, 1C NMR, and mass spectrometry.

[0094] 1 H NMR (400MHz, CD3CN), δ = 8.90 (d, J = 6Hz, 4H), 8.28 (s, 4H), 8.79 (m, 8H), 7.89 (d, J = 6 Hz, 4H), 7.47 (d, J = 6.4Hz, 4H), 7.28 (m, 16H), 7.15 (t, J = 14.8Hz, 8H), 7.00 (m, 24H).

[0095] 13 C NMR (126MHz, CDCl3, ppm): δ = 159.79, 152.99, 152.05, 151.78, 150.53, 149.94, 146.20, 14 2.69,141.32,130.26,129.33,128.20,127.59,127.18,125.97,122.53,121.71,121.63.

[0096] ESI-MS (1949.26 calcd. For C 112 H 80 ZnF 12 N 12 P2):m\z 829.2922[M-2PF6] 2+ (calcdm / z:829.2960).

[0097] Preparation of complex 8:

[0098] Target product:

[0099] The ligand (compound 5) (184.07 mg, 230.6 μmol) was accurately weighed using a four-digit balance and dissolved in 34 mL of chloroform. Then, 26 mL of analytical grade methanol was added. A methanol solution of zinc nitrate hexahydrate (34.39 mg, 115.6 μmol) was accurately pipetted and added to the mixture containing the dissolved ligand while stirring. The mixture was incubated overnight at 65 °C. After the reaction was complete and cooled to room temperature, 10 equivalents of ammonium hexafluorophosphate (NH4PF6) were weighed and added to the mixture. After addition to the reaction system, the mixture was dissolved by sonication to obtain a red flocculent. The mixture was stirred for 1 hour until complete displacement of the flocculent. Filtering using a funnel yielded 71 mg of a red solid, with a yield of 50%. The red solid product was analyzed by 1H NMR, 1C NMR, and mass spectrometry.

[0100] 1 H NMR (400MHz, CD3CN) δ = 8.90 (d, J = 6Hz, 4H), 8.28 (s, 4H), 8.79 (m, 8H), 7.89 (d, J = 6H) z, 4H), 7.47 (d, J = 6.4Hz, 4H), 7.28 (m, 16H), 7.15 (t, J = 14.8Hz, 8H), 7.00 (m, 24H).

[0101] 13 C NMR (126MHz, CDCl3, ppm): δ = 159.79, 152.99, 152.05, 151.78, 150.53, 149.94, 146.20, 14 2.69,141.32,130.26,129.33,128.20,127.59,127.18,125.97,122.53,121.71,121.63.

[0102] ESI-MS (1949.26 calcd. For C 112 H 80 ZnF 12 N 12 P2):m\z 829.2922[M-2PF6] 2+ (calcdm / z:829.2960).

[0103] Preparation of complex 9:

[0104] Target product:

[0105] The ligand (compound 6) (184.07 mg, 230.6 μmol) was accurately weighed using a four-digit balance and dissolved in 21 mL of chloroform. Then, 23 mL of analytical grade methanol was added. A methanol solution of zinc nitrate hexahydrate (32.87 mg, 110.5 μmol) was accurately pipetted and added to the mixture containing the dissolved ligand while stirring. The mixture was incubated overnight at 65 °C. After the reaction was complete and cooled to room temperature, 10 equivalents of ammonium hexafluorophosphate (NH4PF6) were weighed and added to the mixture. After addition to the reaction system, the mixture was dissolved by sonication to obtain a red flocculent. The mixture was stirred for 1 hour until complete displacement of the flocculent. Filtering using a funnel yielded 114 mg of red solid, with a yield of 80%. The red solid product was analyzed by 1H NMR, 1C NMR, and mass spectrometry.

[0106] 1 H NMR (400MHz, CD3CN). δ = 9.50 (d, J = 1.2Hz, 2H), 8.95 (t, J = 3.6Hz, 2H), 8.86 (d, J = 2.4Hz, 2H), 8.00 (m, 8H), 8.69 (s, 4H), 7.97(m,8H),7.45(d,J=8.4Hz,8H),7.28(m,16H),7.15(t,J=14.8Hz,8H),7.01(d,J=9.2Hz,8H),6.92(d,J=7.6Hz,16H)

[0107] 13 C NMR (126MHz, CDCl3, ppm): δ = 159.92, 151.98, 150.92, 150.49, 149.95, 147.81, 147.20, 146.25, 14 5.99,144.32,141.29,130.32,129.43,128.29,127.61,127.08,125.88,121.79,120.08,117.25.

[0108] ESI-MS (967.11 calcd. For C 110 H 78 ZnF 12 N 14 P2):m\z 1949.51[M-2PF6] 2+ (calcd m / z:830.2913).

[0109] Table 1. Crystal data for complex 7.

[0110]

[0111] a GooF=[Σw(|Fo |-|F c |) 2 / (N obs -N param )] 1 / 2 .

[0112] b R1=Σ||F o |-|F c || / Σ|F o | c wR2[(Σw|F o |-|F c |) 2 / Σw 2 |F o | 2 1 / 2.

[0113] Table 2 shows partial bond lengths and bond angles of coordination compound 7.

[0114]

[0115]

[0116] UV-Vis spectroscopy experiment:

[0117] Prepare solutions of complexes 7, 8, and 9 at concentrations of 10 in 3.5 mL cuvettes. -5 Solutions with a concentration of mol / L were prepared, with solvent ratios of water / acetonitrile ranging from 0 to 19. Absorption curves from 260 nm to 500 nm were collected using UV-Vis spectroscopy. Comparison of absorption intensity changes confirmed the aggregation-induced phenomenon.

[0118] Fluorescence spectroscopy experiment:

[0119] Solid-state fluorescence spectroscopy of the ligand and its corresponding complex revealed a redshift of nearly 200 nm after coordination with zinc, caused by an electron push-pull effect. Furthermore, due to aggregation-induced emission, the complex exhibited no fluorescence emission in pure acetonitrile solvent, but produced red light emission as high as 690 nm when the volume ratio of highly aggregated water to acetonitrile was greater than 4:1. As shown in the attached figure, significant fluorescence changes were observed before and after the fluorescent lamp was turned on.

[0120] Detection of reactive oxygen species:

[0121] At a light intensity of 200 mW / cm² -2 Under these conditions, 10 μmol of complex 7 was dissolved in a mixed solvent of water / acetonitrile (volume ratio 1:9) (concentration 10 μmol). -5(mol / L). Simultaneously, DMPO containing the scavenging agent TEMP was added. EPR spectra were measured under both light and dark conditions. The results showed that complex 7 produced two types of reactive oxygen species under light conditions: singlet oxygen and hydroxyl radicals.

[0122] Detection of singlet oxygen:

[0123] Prepare solutions of 3.3 × 10⁻⁶ solution in 3.5 mL cuvettes. -5 Complexes 7 and 8, and methylene blue, have a concentration of 10 mol / L. -5 A solution with a solvent volume ratio of water / acetonitrile / DMSO of 1:0.1:8.9 was prepared. Absorption curves from 300 nm to 500 nm were collected using UV-Vis spectroscopy. The rate of singlet oxygen production was verified by observing the change in the absorption peak of the characteristic peak of 9,10-anthrayl-bis(methylene)dimalonic acid at 400 nm with illumination time.

[0124] The foregoing shows and describes the main methods for preparing complexes 7, 8, and 9, their fluorescence properties, and their photosensitivity.

[0125] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles and methods of this invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A zinc terpyridine complex, characterized in that: It has the structure of Formula 1: Formula 1; in, X is the equilibrium anion; R1 is ； R2 has the following structural units: ； Y represents an oxygen atom or a sulfur atom; R3 is a C1~C5 alkyl group or a hydrogen atom.

2. The zinc terpyridine complex according to claim 1, characterized in that: X is PF6 - ; R3 is a methyl group.

3. A method for preparing a zinc terpyridine complex according to claim 1 or 2, characterized in that: Includes the following steps: 1) 2-Bromo-6-acetylpyridine was reacted with an aldehyde compound of formula 2 and ammonia via a Michael addition-ring-closing reaction to obtain a dibromo-terpyridine compound of formula 3; 2) By coupling a dibromo-terpyridine compound with a borate compound of formula 4, a terpyridine ligand of formula 5 is obtained; 3) After the terpyridine ligand undergoes a coordination reaction with the zinc salt, an anion substitution reaction is carried out to obtain the product; ； in, R1 is ； R2 has the following structural units: ； Y represents an oxygen atom or a sulfur atom; R3 is a C1~C5 alkyl group or a hydrogen atom.

4. The method for preparing a zinc terpyridine complex according to claim 3, characterized in that: In the presence of a base, 2-bromo-6-acetylpyridine undergoes a Michael addition reaction with an aldehyde compound of formula 2, followed by the addition of ammonia to initiate a ring-closing reaction.

5. The method for preparing a zinc terpyridine complex according to claim 4, characterized in that: The conditions for the Michael addition reaction are: reaction at room temperature for 6-10 hours.

6. The method for preparing a zinc terpyridine complex according to claim 4, characterized in that: The conditions for the closed-loop reaction are: reaction at 70~90℃ for 16~32 hours.

7. The method for preparing a zinc terpyridine complex according to claim 3, characterized in that: In the presence of a base, dibromo-terpyridine compounds and borate compounds of formula 4 undergo a coupling reaction catalyzed by tetra(triphenylphosphine)palladium(0).

8. The method for preparing a zinc terpyridine complex according to claim 7, characterized in that: The coupling reaction is performed at 75-85°C for 30-60 hours.

9. The method for preparing a zinc terpyridine complex according to claim 3, characterized in that: The conditions for the coordination reaction are: reaction at 60~70℃ for 18~32 hours.

10. The application of the zinc terpyridine complex according to claim 1 or 2, characterized in that: It is used to prepare photosensitizers or as a luminescent material in light-emitting devices.

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