Terpyridine zinc complex as well as preparation method and application thereof

Abstract

The invention discloses a terpyridyl zinc complex as well as a preparation method and application thereof, and belongs to the technical field of materials. The terpyridyl zinc complex has the following molecular structure: # imgabs0 #, wherein X is a balancing anion; r1 and R2 are independently selected from a nitrogen heterocyclic unit, a benzene ring unit or a triphenylamine unit. The compound has semiconductor properties, can generate hydrogen peroxide with water and oxygen under sunlight illumination, and can be used as a photosensitizer or a photocatalyst.

Description

Technical Field

[0001] The invention relates to a zinc complex, in particular to a terpyridine zinc complex, and also to a preparation method of the terpyridine zinc complex and application of the terpyridine zinc complex as a photocatalyst or photosensitizer, belonging to the technical field of materials. Background Art

[0002] Over the past few decades, due to the growing awareness of the ongoing energy crisis and increasingly serious environmental pollution, photocatalytic technology for directly converting solar energy into fuels has attracted extensive research. So far, inorganic semiconductor materials and organic polymer materials, such as MOF, COF and polymeric carbon nitride (C3N4), etc. ("Molecular-Level Regulation Strategies Toward Efficient Charge Separation in Donor-Acceptor Type Conjugated Polymers for Boosted Energy-Related Photocatalysis", Wang, L., et al. Advanced Energy Materials 2023, 14, 2303346). Due to the characteristics of visible light response, environmental friendliness and structural tunability, these materials have also been widely used as photocatalysts in the past decade. Relatively speaking, molecular photocatalysts have designable structures and tunable photophysical properties at the atomic level, and thus have outstanding intrinsic activity. In the field of organic molecular photocatalysis, due to the high exciton binding energy and short excited state lifetime of organic molecules, it is necessary to construct a strong built-in electric field through molecular assembly to achieve the formation and subsequent migration of long-lived photogenerated carriers. In addition, precious metal compounds with long-lived triplet state characteristics such as ruthenium, iridium, platinum and rhenium complexes have been widely used as photosensitizers in homogeneous photosynthesis due to their long excited state lifetime and sufficient time for reaction. However, the migration process of photogenerated electrons and holes between photosensitive units to catalyst sites is very complicated, and the understanding and effective management of this process are full of obstacles, which seriously hinders the development of photocatalytic technology.

[0003] The molecular photocatalytic systems currently under study usually consist of two parts: a photosensitizer responsible for absorbing visible light to produce excitons and a catalyst responsible for carrying out chemical reactions. Single-molecule catalysts, while acting as both photosensitizers and photocatalysts, have the fundamental advantage of achieving superior performance due to their atomic economy and structural precision. Summary of the invention

[0004] In order to solve the technical problems existing in the prior art, the first object of the present invention is to provide a terpyridine zinc complex, which has semiconductor properties and can produce hydrogen peroxide with water and oxygen under sunlight.

[0005] The second object of the present invention is to provide a method for synthesizing a terpyridine zinc complex, which has mild reaction conditions, simple operation and is easy to expand production.

[0006] The third object of the present invention is to provide an application of a terpyridine zinc complex as a photosensitizer or photocatalyst. The terpyridine zinc complex can quickly achieve electron-hole separation under the excitation of a xenon lamp, and can induce a variety of free radicals within the valence band and conduction band. At the same time, under the irradiation of the sunlight band, it can combine with oxygen in an aqueous solution to efficiently produce hydrogen peroxide, so that it can be used as a photosensitizer, photocatalyst and other fields with broad application prospects.

[0007] In order to achieve the above technical objectives, the present invention provides a terpyridine zinc complex having a molecular structure shown in Formula 1:

[0008]

[0009] in,

[0010] X is a counter anion;

[0011] R1 and R2 are independently selected from a nitrogen heterocyclic unit, a benzene ring unit or a triphenylamine unit.

[0012] The terpyridine zinc complex of the present invention uses transition metal zinc as the central metal ion and terpyridine as a multidentate ligand. The terpyridine ligand can form a stable terpyridine zinc complex with a pseudo-octahedral structure with zinc ions. The terpyridine ligand of the terpyridine zinc complex introduces a triphenylamine group and a nitrogen heterocyclic group with high electron-donating ability. The terpyridine ligand itself has a strong electron-withdrawing ability. The strong electron-donating ability of the triphenylamine group and the nitrogen heterocyclic group further enhances the push-pull effect of electrons and the special charge transfer effect, so that the terpyridine zinc complex has an extremely small energy gap difference (ΔE ST ), and under sunlight conditions, the terpyridine zinc complex can combine water and oxygen to generate highly efficient hydrogen peroxide, and can be used as a very good photocatalyst or photosensitizer.

[0013] As a preferred embodiment, in the terpyridine zinc complex, X is PF6 - The terpyridine zinc complex of the present invention is selected from PF6 - As a counter anion, compared to NO3 -Other anions such as terpyridine zinc complex can better improve the hydrophilicity of the complex.

[0014] As a preferred solution, R1 is

[0015] As a preferred solution, R2 is

[0016]

[0017] In the terpyridine zinc complex of the present invention, R1 and R2 are preferably nitrogen heterocycles or triphenylamine groups. By selecting a unit with a strong electron-donating ability, the energy level of the electron acceptor unit can be effectively adjusted.

[0018] The present invention also provides a method for synthesizing a terpyridine zinc complex, which comprises the following steps:

[0019] 1) reacting 2-bromo-6-acetylpyridine with an aldehyde compound of formula 2 and aqueous ammonia through a Michael addition-ring closure reaction to obtain a terpyridine ligand of formula 3;

[0020]

[0021]

[0022] 2) 2-bromo-6-acetylpyridine and 3,5-di-tert-butylbenzaldehyde are subjected to a condensation reaction to obtain an intermediate of formula 4; the intermediate of formula 4 is subjected to a Michael addition-ring closure reaction with 2-acetylpyridine and ammonia to obtain a brominated terpyridine compound of formula 5; the brominated terpyridine compound is subjected to a coupling reaction with a boric acid compound of formula 6 to obtain a terpyridine ligand of formula 7;

[0023] 3) performing coordination reaction on the terpyridine ligand of formula 3, the terpyridine ligand of formula 7 and a zinc salt solution, and then performing anion replacement reaction to obtain;

[0024]

[0025]

[0026] Wherein, R1 and R2 are independently selected from a nitrogen heterocyclic unit, a benzene ring unit or a triphenylamine unit; further preferably:

[0027] R1 is R2 is

[0028] As a preferred solution, in step 1), in the presence of a base, 2-bromo-6-acetylpyridine and the aldehyde compound of formula 2 undergo Michael addition reaction, and then ammonia water is added to perform a ring-closing reaction. As a more preferred solution, the conditions for the Michael addition reaction are: at room temperature, the reaction time is 6 to 10 hours; the conditions for the ring-closing reaction are: at a temperature of 70 to 90° C., the reaction time is 16 to 32 hours. The base is, for example, sodium hydroxide.

[0029] As a preferred solution, in step 2), 2-bromo-6-acetylpyridine and 3,5-di-tert-butylbenzaldehyde are reacted in an ice bath in the presence of a base for 8 to 16 hours. The ice bath environment is generally at a temperature of -5°C to 0°C.

[0030] As a preferred scheme, in step 3), in the presence of a base, the intermediate of formula 4 undergoes a Michael addition reaction with 2-acetylpyridine, and then ammonia water is added to carry out a ring-closing reaction; the conditions of the Michael addition reaction are: reacting at room temperature for 6 to 10 hours; the conditions of the ring-closing reaction are: reacting at a temperature of 70 to 90°C for 16 to 32 hours.

[0031] As a preferred solution, in step 2), in the presence of a base, the brominated terpyridine compound and the boronic acid compound of formula 6 undergo a coupling reaction at 75 to 85° C. under the catalysis of a palladium catalyst for 30 to 60 hours.

[0032] As a preferred solution, the conditions of the coordination reaction are: at a temperature of 60 to 70° C. and for 18 to 32 hours.

[0033] The invention also provides an application of the terpyridine zinc complex, which is used as a photosensitizer or a photocatalyst.

[0034] As a preferred solution, the terpyridine zinc complex has the characteristic of generating singlet oxygen and superoxide radicals under sunlight irradiation.

[0035] The photocatalytic principle of the terpyridine zinc complex of the present invention: the photocatalytic process is mainly divided into two processes: oxygen reduction (ORR) and water oxidation (WOR). The ORR process is mainly manifested in two processes: oxygen → superoxide anion (-0.33V NHE) → hydrogen peroxide and oxygen → hydrogen peroxide (0.28V NHE). In order to balance electrons and holes, a two-electron process of water → hydrogen peroxide (1.35V NHE) occurs at the WOR end.

[0036] The terpyridine zinc complex provided by the present invention can generate a variety of active oxygen species under the excitation of a xenon lamp. At the same time, the terpyridine zinc complex can generate active oxygen species such as singlet oxygen and superoxide free radicals under sunlight irradiation conditions. The active oxygen forms hydrogen peroxide by combining with water or oxygen, and its rate is at the top level in the field. In addition, no sacrificial agent or photosensitizer needs to be added in this system, so it can act as a photosensitizer and a photocatalyst at the same time.

[0037] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0038] The terpyridine zinc complex provided by the present invention uses metallic zinc as the central metal ion. The metallic zinc belongs to the first period transition metal, is cheaper than metallic platinum, gold and iridium, and has lower pollution to the environment.

[0039] The terpyridine zinc complex provided by the present invention can generate active oxygen species such as singlet oxygen and superoxide free radicals under sunlight irradiation conditions, and exhibits good photosensitivity.

[0040] The preparation method of the terpyridine zinc complex provided by the invention has simple operation and steps, low cost and is conducive to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Solid UV images of complexes 13 to 16.

[0042] Figure 2 Solid transient photoluminescence spectra of complexes 13 to 16 at different temperatures.

[0043] Figures 3 to 6 The ESR spectra of complexes 13 to 16 under xenon lamp irradiation.

[0044] Figure 7 The standard curve for measuring hydrogen peroxide concentration and absorption is shown in Figure 2.

[0045] Figure 8 This is a statistical chart of hydrogen peroxide produced by complexes 13 to 16 after being illuminated under a 10W xenon lamp for a period of time. DETAILED DESCRIPTION

[0046] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0047] The substrate materials and solvents involved in the following examples are all commercial products (analytical grade reagents). All reagents used have been purified, dried and pretreated, and the synthesis and treatment processes involved use standard anhydrous and oxygen-free techniques.

[0048] 1 H NMR (400 MHz), with CDCl3 and CD3CN as solvents and TMS as internal standard.

[0049] Multiplicities are defined as follows: s (singlet); d (doublet); t (triplet); q (quartet) and m (multiplet). Absorption intensity is defined as follows.

[0050] Unless otherwise specified, all professional terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not all within the scope of protection of the present invention.

[0051] Example 1

[0052] Target product: Compound 1: Compound 2: Compound 3: Compound 4: Compound 5: Compound 6: Compound 1:

[0053] To a solution of 4-pyridinecarboxaldehyde (1 g, 10 mmol) in ethanol (60 mL) was added p-bromoacetophenone (5.97 g, 30 mmol) and NaOH powder (4 g, 100 mmol). After stirring at room temperature for 24 hours, aqueous ammonia (28%, 25 mL) was added and the resulting mixture was refluxed at 85° C. for 20 hours. After cooling to room temperature, the solid was collected by suction filtration and washed with methanol to obtain 3.5 g of a yellow solid product (yield 75%).

[0054] Compound 2:

[0055] Compound 1 (3.82 g, 8.2 mmol) and bis(pinac acid) diboron (2.7 g, 10.6 mmol) were mixed in a 100 mL flask, and then 1,4-dioxane (50 mL) and potassium acetate (2.4 g, 24.6 mmol) were added. The system was degassed for 10 minutes, and 1,1'-bis(diphenylphosphino)ferrocenepalladium dichloride (351 mg, 0.5 mmol) was added as a catalyst. The mixture was stirred at 85 ° C for 8 hours under nitrogen, cooled to ambient temperature, concentrated in vacuo, and then subjected to column chromatography (alumina), eluted with a mixture of petroleum ether and dichloromethane, and the product was purified to obtain 3.15 g of a white solid (yield 75%).

[0056] Compound 3:

[0057] 3,5-bis(tert-butyl)benzaldehyde (8.73 g, 40 mmol) solution was added dropwise to a stirred emulsion containing 2-acetyl-6-bromopyridine (8.0 g, 40 mmol) and potassium hydroxide (1.8 g, 32 mmol) in 150 mL of methanol. After stirring in an ice bath for 12 hours, the resulting pale yellow solid was filtered out, washed with cold methanol, and dried in vacuo to give 10 g of a white solid product (yield 55%).

[0058] Compound 4:

[0059] 2-Acetylpyridine (3.63 g, 30 mmol) and sodium hydroxide powder (4 g, 100 mmol) were added to a solution of compound 3 (4 g, 10 mmol) in ethanol (60 mL). After stirring at room temperature for 24 hours, an aqueous ammonia solution (28%, 25 mL) was added and the resulting mixture was refluxed for 20 hours. After cooling to room temperature, the solid was collected by suction filtration and washed with methanol to obtain 2.042 g of a white solid product (yield 43.7%).

[0060] Compound 5:

[0061] A mixed solvent (48 mL) of tetrahydrofuran / water (8:1, v / v) was added to a flask containing compound 2 (500 mg, 1.38 mmol) and (3-(trimethylsilyl)phenyl)boric acid (808 mg, 4 mmol) and sodium hydroxide (0.2 g, 50.00 mmol). Tetrakis triphenylphosphine palladium (0.2 g, 0.18 mmol) was then added, the system was pumped and backfilled with nitrogen. The mixture was refluxed under nitrogen for 3 days. After cooling to 25 ° C, the mixture was extracted with dichloromethane, and the combined organic extracts were evaporated to dryness in vacuo to obtain a residue, which was washed with methanol and then subjected to column chromatography (alumina, dichloromethane / methanol=100:1), and the main portion was then recrystallized from a chloroform / methanol mixture to obtain (77%) compound 3 as a white solid 0.569 g (0.71 mmol).

[0062] Compound 6:

[0063] Liquid bromine (3 ml) was added to a solution of compound 5 (500 mg) in dichloromethane (50 mL), and stirred at 25° C. for 24 hours. Then, sodium bisulfite (5 g) and sodium bicarbonate (5 g) were added to adjust the pH value to weak alkalinity, the organic phase was extracted, the mixture was extracted with dichloromethane, and the combined organic extracts were vacuum evaporated to dryness to obtain a residue, which was washed with methanol and eluted with methanol to obtain a white solid (1.55 g, 35.7%). Compound 1: 1H NMR (400MHz, CDCl3, ppm): δ=8.73–8.67(m,2H),8.03–7.93(m,4H),7.77(s,2H),7.61–7.51(m,6H).13C NMR(101MHz,Chloroform-d)δ156.93,150.77,147.88,146.07,137.71,132.02,128.65,124.08,121.61,116.70.ESI-MS(466.18calcd.For C 22 H 14 Br2N2):m / z=466.9016[M+H + ] + (calcd.m / z=467.18).Compound 2: 1 HNMR (400MHz, CDCl3, ppm): δ = 8.71 (d, J = 6.1Hz, 2H), 8.12 (d, J = 8.1Hz, 4H), 7.89 (d, J = 7.8Hz, 4H), 7.85 (s, 2H), 7.61 (d, J = 6.1Hz, 2H), 1.31 (s, 24H). 13C NMR(101MHz,Chloroform-d)δ156.86,149.38,146.36,145.61,140.43,134.24,127.81,126.13,125 .31,125.28,120.77,120.75,116.17,82.94,82.04,23.87,23.80,23.51.ESI-MS(560.31calcd.For C 34 H 38 B2N2O2):m / z=561.3250[M+H + ] + (calcd.m / z=561.31).

[0064] Compound 3: 1H NMR (400MHz, CDCl3, ppm): δ=8.20–8.10(m,2H),8.01(d,J=16.0Hz,1H),7.80–7.67(m,2H),7.56(dd,J=12.2,1.8Hz,3H),1.40(s,18H).13C NMR(101MHz,Chloroform-d)δ187.99,155.32,151.46,147.27,141.30,139.28,1 34.27,131.46,125.51,123.40,121.83,119.56,31.42.ESI-MS(400.36calcd.For C 22 H 26 BrNO): m / z = 402.1026 [M+H + ] + (calcd.m / z=401.36).

[0065] Compound 4: 1 H NMR (400MHz, CDCl3, ppm): δ = 8.66 (d, J = 6.6Hz, 1H), 8.60 (s, 1H), 8.54 (d, J = 8.0Hz, 3H), 7.79 (t, J = 7. 7Hz,1H),7.63(t,J=7.8Hz,1H),7.52(s,2H),7.49–7.41(m,2H),7.31–7.24(m,1H),1.34(s,18H).13C NMR(101MHz,Chloroform-d)δ157.70,156.26,155.90,154.17,152.30,151.49,149.21,141.63,139.11,138.3 1,136.84,128.00,123.83,123.15,121.79,121.41,120.11,120.09,120.01,31.61.ESI-MS(500.48calcd.ForC 29 H 30 BrN3):m / z=502.1694[M+H + ] + (calcd.m / z=501.48).

[0066] Compound 5: 11H NMR (400 MHz, Chloroform-d) δ 8.85 (d, J = 1.7 Hz, 1H), 8.66 (d, J = 5.7 Hz, 1H), 8.60 (d, J = 6.6 Hz, 2H), 8.54 (d, J = 8.8 Hz, 1H), 8.10 (d, J = 8.1 Hz, 2H), 7.93–7.81 (m, 2H), 7.76 (d, J = 7.9 Hz, 1H), 7.63 (d, J = 1.8 Hz, 2H), 7.58 (d, J = 8.1 Hz, 2H), 7.49 (t, 1H), 7.33–7.28 (m, 1H), 1.37 (s, 18H), 0.25 (s, 9H). 13C NMR (101 MHz, Chloroform-d) δ 155.56, 155.31, 155.07, 154.98, 154.64, 150.79, 150.45, 148.07, 140.51, 138.66, 137.52, 136.56, 135.88, 132.70, 125.15, 122.69, 122.02, 120.78, 120.52, 119.22, 118.89, 118.66, 118.43, 30.53. ESI-MS (569.87 calcd. For C 38 H 43 N3Si): m / z = 570.3140 [M + H + + (calcd. m / z = 570.87).

[0067] Compound 6: 1 ​H NMR(400MHz,Chloroform-d)δ8.83(d,J=1.7Hz,1H),8.70(d,J=4.8Hz,1H),8.66–8.56(m,3H),8.02(d,J=8.3Hz,2H),7.87(dt,J= 15.3,7.8Hz,2H),7.73(d,J=7.9Hz,1H),7.61(d,J=1.7Hz,2H),7.58–7.46(m,3H),7.31(dd,J=11.8,5.5Hz,1H),1.37(s,18H).13C NMR(101MHz,Chloroform-d)δ155.42,154.97,154.73,154.70,153.96,150.73,150.48,148.09,137.41,137.10,136.75,135.8 5,130.78,127.40,122.73,122.44,122.08,120.74,120.46,118.87,118.84,118.78,118.46,30.51.ESI-MS(576.58calcd.For C 35 H 34 BrN3):m / z=578.2301[M+H + ] + (calcd.m / z=577.58).

[0068] Example 2

[0069] Target product: Compound 7: Compound 8: Compound 9: Compound 10: Compound 11: Compound 12: Compound 7: 2-acetylpyridine (6.057 g, 50 mmol) and sodium hydroxide powder (4 g, 100 mmol) were added to a solution of isophthalaldehyde (1.34 g, 10 mmol) in ethanol (60 mL). After stirring at room temperature for 24 hours, an aqueous ammonia solution (28%, 25 mL) was added and the resulting mixture was refluxed for 20 hours. After cooling to room temperature, the solid was collected by suction filtration and washed with methanol to obtain 2.042 g of a white solid product (yield 43.7%).

[0070] Compound 8: 2-acetylpyridine (6.057 g, 50 mmol) and sodium hydroxide powder (4 g, 100 mmol) were added to a solution of 2,6-pyridinedicarboxaldehyde (1.34 g, 10 mmol) in ethanol (60 mL). After stirring at room temperature for 24 hours, an aqueous ammonia solution (28%, 25 mL) was added and the resulting mixture was refluxed for 20 hours. After cooling to room temperature, the solid was collected by suction filtration and washed with methanol to obtain 2.3 g of a white solid product (yield 43%).

[0071] Compound 9: A mixed solvent (44 mL) of tetrahydrofuran / water (10:1, v / v) was added to a flask containing 2,6-dibromopyridine (1 g, 4.2 mmol) and (4-([2,2':6',2'-pyridine]-4'-yl)phenyl)boric acid (4.5 g, 12.6 mmol) and potassium carbonate (2.76 g, 20 mmol). Tetrakistriphenylphosphine palladium (0.208 g, 0.18 mmol) was then added, the system was pumped and backfilled with nitrogen. The mixture was refluxed under nitrogen for 3 days. After cooling to 25 °C, the mixture was washed with methanol and water to give (77%) 2.5 g (3.6 mmol) of a white solid.

[0072] Compound 10: A mixed solvent (44 mL) of tetrahydrofuran / water (10:1, v / v) was added to a flask containing compound 6 (200 mg, 0.37 mmol) and 4'-bromo-2,2':6',2'-tripyridine (550 mg, 1.1 mmol) and potassium carbonate (690 mg, 5 mmol). Tetrakis triphenylphosphine palladium (0.208 g, 0.18 mmol) was then added, the system was pumped and backfilled with nitrogen. The mixture was refluxed under nitrogen for 3 days. After cooling to 25 ° C, the mixture was extracted with dichloromethane, and the combined organic extracts were evaporated to dryness in vacuo to obtain a residue, which was washed with methanol to obtain (77%) 0.569 g (0.71 mmol) of a yellow solid.

[0073] Compound 11: A mixed solvent (48 mL) of tetrahydrofuran / water (8:1, v / v) was added to a flask containing compound 2 (1.25 g, 2.5 mmol) and phenylbis-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxolan-2-yl)-phenyl]-amine (500 mg, 1.005 mmol) and potassium carbonate (6.9 g, 5 mmol). Tetrakis triphenylphosphine palladium (0.2 g, 0.18 mmol) was then added, the system was pumped and backfilled with nitrogen. The mixture was refluxed under nitrogen for 3 days. After cooling to 25 ° C, the mixture was extracted with dichloromethane, and the combined organic extracts were evaporated to dryness in vacuo to obtain a residue, which was washed with methanol and then subjected to column chromatography (alumina, dichloromethane / petroleum ether = 1:4) as a white solid: 0.800 g (0.7 mmol).

[0074] Compound 12: A mixed solvent (48 mL) of tetrahydrofuran / water (8:1, v / v) was added to a flask containing 4 (1.44 mg, 2.5 mmol) and phenylbis-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxolan-2-yl)-phenyl]-amine (500 mg, 1.005 mmol) and potassium carbonate (690 mg, 5 mmol). Tetrakis triphenylphosphine palladium (0.2 g, 0.18 mmol) was then added, the system was pumped and backfilled with nitrogen. The mixture was refluxed under nitrogen for 3 days. After cooling to 25 ° C, the mixture was extracted with dichloromethane, and the combined organic extracts were evaporated to dryness in vacuo to give a residue, which was washed with methanol and then subjected to column chromatography (alumina, dichloromethane / petroleum ether=1:4) as a white solid 0.569 g (0.71 mmol).

[0075] Compound 7: 1 H NMR (400MHz, Chloroform-d) δ = 8.75 (s, 4H), 8.67 (d, J = 3.0Hz, 4H), 8.63 (d, J = 7.9Hz, 4H), 8.2 8(s,1H),7.91(d,J=7.7Hz,2H),7.83(t,J=6.8Hz,4H),7.60(t,J=7.7Hz,1H),7.29(t,4H).13C NMR(101MHz,Chloroform-d)δ156.18,156.00,150.18,149.16,139.57,136.92,129.59,128.17,126.21,123.89,121.44,119.25.ESI-MS(540.63calcd.For C 35 H 23 N7): m / z = 541.22 [M+H + ] + (calcd.m / z=541.63).

[0076] Compound 8: 11H NMR (400 MHz, Chloroform-d) δ = 9.17 (s, 4H), 8.69 (d, J = 3.9 Hz, 4H), 8.60 (d, J = 7.9 Hz, 4H), 8.04 (d, J = 7.8 Hz, 2H), 7.90 (t, 1H), 7.79 (dd, J = 7.7, 1.8 Hz, 4H), 7.31–7.25 (m, 4H). 13C NMR (101 MHz, Chloroform-d) δ 156.24, 156.13, 155.09, 149.16, 148.46, 137.92, 136.94, 123.86, 121.48, 121.28, 118.95. ESI-MS (541.62 calcd. For C 36 H 24 N6: m / z = 542.20 [M+H + + (calcd. m / z = 542.62).

[0077] Compound 9: 1 1H NMR (400 MHz, Chloroform-d) δ = 8.74 (s, 4H), 8.68 (d, J = 7.6 Hz, 1H), 8.61 (d, J = 10.0 Hz, 1H), 8.26 (d, 2H), 8.02 (d, J = 8.4 Hz, 3H), 7.83 (d, J = 1.9 Hz, 3H), 7.31 (dd, J = 7.5, 4.8 Hz, 3H). 13C NMR (101 MHz, Chloroform-d) δ 156.27, 156.01, 149.16, 136.97, 127.75, 127.57, 123.89, 121.46, 118.90. ESI-MS (693.81 calcd. For C 47 H 31 N 7) : m / z = 694.19 [M+H + + (calcd. m / z = 694.81).

[0078] Compound 10: 1 ​​1H NMR (400 MHz, Chloroform-d) δ = 8.79–8.74 (m, 6H), 8.70 (ddd, J = 4.8, 1.8, 0.9 Hz, 4H), 8.63 (dt, J = 7.9, 1.1 Hz, 4H), 8.31 (d, 4H), 8.04 (d, 4H), 7.94 (s, 2H), 7.84 (td, J = 7.7, 1.8 Hz, 4H), 7.69–7.63 (m, 2H), 7.31 (ddd, J = 7.6, 4.8, 1.3 Hz, 4H). 13C NMR (101 MHz, Chloroform-d) δ 156.41, 155.22, 155.05, 149.72, 148.66, 148.16, 138.52, 138.44, 135.90, 126.82, 126.67, 122.88, 120.72, 120.41, 117.83, 116.06. ESI-MS (770.90 calcd. For C 52 H 34 N8): m / z = 771.31 [M+H + + (calcd. m / z = 771.90).

[0079] Compound 11: 1 ​1H NMR (400 MHz, Chloroform-d) δ = 8.83 (d, J = 1.6 Hz, 2H), 8.71–8.66 (m, 2H), 8.63 (dt, J = 7.6, 1.3 Hz, 4H), 8.52 (dd, J = 7.7, 0.8 Hz, 2H), 8.07–8.00 (m, 4H), 7.85 (td, J = 7.7, 5.3 Hz, 4H), 7.70 (dd, J = 7.9, 0.9 Hz, 2H), 7.59 (d, J = 1.8 Hz, 4H), 7.45 (t, J = 1.8 Hz, 2H), 7.30 (ddd, J = 7.5, 4.8, 1.2 Hz, 2H), 7.24 (dd, J = 8.5, 7.2 Hz, 2H), 7.19–7.13 (m, 8H), 7.03 (t, 2H), 1.32 (s, 36H). 13C NMR (101 MHz, Chloroform-d) δ 156.42, 156.11, 155.91 (d, J = 3.8 Hz), 151.89, 151.45, 148.97, 148.39, 147.21, 138.51, 137.64, 137.11, 133.75, 129.41, 127.94, 124.93, 123.99, 123.78, 123.58, 123.05, 121.80, 121.61, 119.95, 119.73, 119.53, 119.18, 31.56. ESI-MS (1084.47 calcd. For C 76 H 73 N7): m / z = 1084.44 [M+H + + (calcd. m / z = 1085.47). Compound 12: 1 1H NMR (400 MHz, Chloroform-d) δ = 8.97 (d, J = 1.7 Hz, 2H), 8.74 (m, J = 4.9, 1.8, 0.9 Hz, 2H), 8.70 (dd, J = 8.3, 1.3 Hz, 4H), 8.62 (d, J = 7.6, 1.0 Hz, 2H), 8.29 (d, J = 8.4 Hz, 4H), 8.01–7.85 (m, 6H), 7.77–7.68 (m, 8H), 7.64–7.54 (m, 6H), 7.41–7.29 (m, 4H), 7.26–7.20 (m, 6H), 7.09 (t, J = 7.3 Hz, 1H), 1.45 (s, 36H). 13 ​CNMR(101MHz,Chloroform-d)δ156.51,156.06,155.93,155.82,155.65,151.80, 151.50,149.09,147.44,147.24,141.23,138.57,137.73,137.68,137.00,134.8 0,129.46,127.89,127.33,126.94,124.85,124.22,123.78,123.41,123.10,121 .87,121.57,120.02,119.97,119.57,119.48,31.60.ESI-MS(1236.67calcd.For C 88 H 81 N7): m / z = 1237.68 [M+H + ] + (calcd.m / z=1237.67).

[0080] Example 3

[0081] Synthesis of complexes 13 to 16:

[0082]

[0083] Where X is PF6 -

[0084] Complex 13: R1 is R2 is Complex 14: R1 is R2 is Complex 15: R1 is R2 is Complex 16: R1 is R2 is Complex 13:

[0085] Formula 7 (50 mg, 92.5 μmol) and Formula 11 (100.3 mg, 92.5 μmol) were added to a mixed solvent of chloroform (20 mL) and methanol (20 ml), followed by a solution of zinc nitrate hexahydrate (55.04 mg, 185 μmol) in methanol (15 mL). After the mixture was stirred at 65° C. for 15 hours, an excess of ammonium hexafluorophosphate was added to precipitate the complex, which was then filtered, washed with water, and then dried in vacuo. 130 mg (55.6 μmol) of the desired yellow solid (92%) was obtained.

[0086] Complex 14:

[0087] Formula 8 (50 mg, 92.48 μmol) and Formula 11 (100.3 mg, 92.5 μmol) were added to a mixed solvent of chloroform (20 mL) and methanol (20 ml), followed by a solution of zinc nitrate hexahydrate (55.04 mg, 185 μmol) in methanol (21.765 mL). After the mixture was stirred at 65° C. for 15 hours, an excess of ammonium hexafluorophosphate was added to precipitate the complex, which was then filtered, washed with water, and then dried in vacuo. The desired yellow solid (92%) was obtained: 130 mg (56 μmol).

[0088] Complex 15:

[0089] Formula 9 (56.10 mg, 80.8 μmol) and Formula 12 (100 mg, 80.0 μmol) were added to a mixed solvent of chloroform (34 mL) and methanol (26 mL), followed by a solution of zinc nitrate hexahydrate (48.1 mg, 161.7 μmol) in methanol (10 mL). After the mixture was stirred at 60° C. for 15 hours, an excess of ammonium hexafluorophosphate was added to precipitate the complex, which was then filtered, washed with water, and then dried in vacuo. The desired yellow solid complex (93%) was obtained: 130 mg (49.23 μmol).

[0090] Complex 16:

[0091] Formula 10 (62.288 mg, 80.8 μmol) and Formula 12 (100 mg, 80.0 μmol) were added to a mixed solvent of chloroform (21 mL) and methanol (23 mL), followed by a solution of zinc nitrate hexahydrate (48.1 mg, 161.7 μmol) in methanol (10 mL). After the mixture was stirred at 65° C. for 15 hours, an excess of ammonium hexafluorophosphate was added to precipitate the complex, which was then filtered, washed with water, and then dried in vacuo. The desired yellow solid complex (80%) was obtained: 130 mg (48 μmol).

[0092] Complex 13: 11H NMR (400 MHz, CD3CN) δ = 9.06 (s, 2H), 8.96 (s, 2H), 8.86 (s, 4H), 8.78 (d, J = 8.0 Hz, 2H), 8.72 (d, J = 8.1 Hz, 2H), 8.61 (d, J = 8.0 Hz, 4H), 8.40 (d, J = 9.4 Hz, 2H), 8.31 (s, 1H), 8.21 (dd, J = 16.5, 8.8 Hz, 9H), 8.01 (d, J = 1.7 Hz, 4H), 7.93–7.82 (m, 6H), 7.66 (d, J = 6.2 Hz, 2H), 7.49 (dd, J = 7.6, 5.2 Hz, 3H), 7.44–7.23 (m, 7H), 6.55 (d, J = 8.4 Hz, 4H), 6.41 (dd, J = 12.8, 8.0 Hz, 6H), 1.55 (s, 36H). ESI-MS (2335.1 calcd. For C 112 H 97 Zn2F 24 N 13 P4): m / z 439.0247 [M - 4PF6] 4+ (calcd m / z: 439.0259); m / z 633.6937 [M - 4PF6] 3+ (calcd m / z: 633.6946).

[0093] Complex 14: 1 1H NMR (400 MHz, CD3CN), δ = 9.26 (s, 4H), 9.08 (s, 2H), 8.95 (s, 2H), 8.83 (d, J = 7.0 Hz, 2H), 8.76–8.58 (m, 9H), 8.36–8.18 (m, 6H), 8.13 (td, J = 7.9, 1.6 Hz, 2H), 8.02 (d, J = 1.8 Hz, 4H), 7.95–7.80 (m, 6H), 7.62 (d, J = 4.6 Hz, 2H), 7.50 (ddd, J = 7.7, 5.0, 1.0 Hz, 4H), 7.45–7.32 (m, 4H), 7.31–7.15 (m, 3H), 6.47 (d, J = 8.6 Hz, 4H), 6.32 (td, J = 6.4, 2.1 Hz, 6H), 1.55 (s, 36H). ESI-MS (2336.1 calcd. For C 111 H 96 Zn2F 24 N 14 P4): m / z 439.2625 [M - 4PF6] 4+(calcd m / z:439.2636); m / z 634.0123[M - 4PF6 ]3+ (calcd m / z:634.0135).

[0094] Complex 15: 1 H NMR(400MHz, CD3CN)δ = 9.11(s, 2H), 9.01–8.85(m, 4H), 8.67(m, J = 8.1Hz, 10H), 8.60(d, J = 8.4Hz, 4H), 8.37(t, J = 7.9Hz, 2H), 8.26(t, J = 7.8Hz, 4H), 8.19(d, J = 4.7Hz, 3H), 8.13–7.98(m, 10H), 7.95–7.84(m, 6H), 7.63–7.46(m, 6H), 7.34(d, J = 4.9Hz, 4H), 7.25(d, J = 3.3Hz, 4H), 7.12(d, J = 8.0Hz, 4H), 7.02(t, J = 7.3Hz, 1H), 6.95–6.79(m, 8H), 6.53(d, J = 8.0Hz, 4H), 1.56(s, 36H). ESI-MS(2640.48 calcd. For C 135 H 112 Zn2F 24 N 14 P4): m / z 515.4154[M - 4PF6] 4+ (calcd m / z:515.4166); m / z 735.5494[M - 4PF6] 3+ (calcd m / z:735.5505).

[0095] Complex 16: 1H NMR (400MHz, CD3CN). δ=9.11(s,2H),8.99(d,J=6.7Hz,2H),8.95–8.90(m,4H),8.68(t,J=7.9Hz,14H),8.52(d,J=9.3Hz ,4H),8.37(t,J=7.9Hz,2H),8.27(t,J=8.6Hz,4H),8.08(dd,J=15.6,8.2Hz,6H),8.02(d,J=1.8Hz,4H),7.96–7.82(m,6 H),7.54(q,J=7.1,6.3Hz,6H),7.34(d,J=8.5Hz,4H),7.28(dd,J=10.9,4.1Hz,4H),7.13(d,J=7.8Hz,4H),6.92(d,J=7. 2Hz,3H),6.86(d,J=8.6Hz,4H),6.80(d,J=9.7Hz,2H),6.53(d,J=8.1Hz,4H),1.55(s,36H).ESI-MS(2717.57calcd.For C 140 H 115 Zn2F 24 N 15 P4):m / z 534.6891[M-4PF6] 4+ (calcd m / z:534.6902); m / z 762.6291[M-4PF6] 3+ (calcd m / z:762.6304).

[0096] Example 4

[0097] Performance test of complexes 13 to 16:

[0098] Drawing of hydrogen peroxide standard curve:

[0099] Water 2 with concentrations of 0.058 mM, 0.113 mM, 0.165 mM, 0.215 mM and 0.265 mM were mixed with 0.4 M potassium iodide and 0.1 M potassium hydrogen phthalate, respectively, and then the absorption peak at 350 nm was detected, and a standard curve of the corresponding concentration and the absorption of the ultraviolet absorption characteristic peak was plotted.

[0100] UV-Vis spectroscopy experiment:

[0101] Take out 0.5 mL of the reaction solution and add 2.5 mL of water to dilute to 3 mL, then add 1 mL of 0.4 mol / L potassium iodide and 0.1 mol / L potassium hydrogen phthalate. After mixing, let it react for half an hour, perform a UV absorption spectrum test, and detect the absorption peak at 350 nm.

[0102] Detection of active oxygen:

[0103] At a light intensity of 200 mW cm -2 Under the condition of , complexes 13, 14, 15, and 16 were placed in an aqueous solution / methanol solution. At the same time, DMPO of the capture agent TEMP was added. The EPR spectra were detected under light conditions and dark conditions. It was found that complex 16 produced two types of reactive oxygen species, singlet oxygen and superoxide radicals, under light conditions.

[0104] The solid UV images of complexes 13 to 16 are shown in Figure 1 As shown, it can be seen from the figure that the complex has a wide absorption range of 200 to 500 nm.

[0105] Solid transient photoluminescence spectra of complexes 13 to 16 at different temperatures are shown in Figure 2 As shown in the figure, it can be seen that complexes 13-16 have long lifetimes, which means that complexes 13-16 have potential properties as photosensitizers.

[0106] The ESR spectra of complexes 13-16 under xenon lamp irradiation are as follows: Figures 3 to 5 As shown in the figure, it can be seen that active oxygen species such as singlet oxygen, superoxide free radicals, and hydroxyl free radicals are generated under light excitation.

[0107] The standard curve of hydrogen peroxide concentration and absorption is as follows Figure 6 shown.

[0108] The statistical graph of hydrogen peroxide produced by complexes 13-16 after being illuminated for a period of time under a 10W xenon lamp is shown in the figure below. Figure 7 As shown in the figure, it can be seen that the above-mentioned complexes have excellent photocatalytic ability.

[0109] Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and the description are only for explaining the principles and methods of the present invention. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and improvements, which are within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A terpyridine zinc complex, characterized in that: It has a molecular structure shown in Formula 1: in, X is a counter anion; R1 and R2 are independently selected from a nitrogen heterocyclic unit, a benzene ring unit or a triphenylamine unit.

2. A terpyridine zinc complex according to claim 1, characterized in that: X is PF6 - ; R1 is R2 is 3. A method for synthesizing a terpyridine zinc complex according to claim 1 or 2, characterized in that: The following steps are involved: 1) reacting 2-bromo-6-acetylpyridine with an aldehyde compound of formula 2 and aqueous ammonia through a Michael addition-ring closure reaction to obtain a terpyridine ligand of formula 3; 2) 2-bromo-6-acetylpyridine and 3,5-di-tert-butylbenzaldehyde are subjected to a condensation reaction to obtain an intermediate of formula 4; the intermediate of formula 4 is subjected to a Michael addition-ring closure reaction with 2-acetylpyridine and ammonia to obtain a brominated terpyridine compound of formula 5; the brominated terpyridine compound is subjected to a coupling reaction with a boric acid compound of formula 6 to obtain a terpyridine ligand of formula 7; 3) performing coordination reaction on the terpyridine ligand of formula 3, the terpyridine ligand of formula 7 and a zinc salt solution, and then performing anion replacement reaction to obtain; in, R1 and R2 are independently selected from a nitrogen heterocyclic unit, a benzene ring unit or a triphenylamine unit.

4. The method for synthesizing a terpyridine zinc complex according to claim 3, characterized in that: In step 1), in the presence of a base, 2-bromo-6-acetylpyridine and the aldehyde compound of formula 2 undergo Michael addition reaction, and then ammonia water is added to perform a ring-closing reaction; The conditions of the Michael addition reaction are: reacting at room temperature for 6 to 10 hours; The conditions of the ring-closing reaction are: reacting at a temperature of 70 to 90° C. for 16 to 32 hours.

5. The method for synthesizing a terpyridine zinc complex according to claim 3, characterized in that: In step 2), 2-bromo-6-acetylpyridine and 3,5-di-tert-butylbenzaldehyde are reacted in the presence of a base in an ice bath for 8 to 16 hours.

6. The method for synthesizing a terpyridine zinc complex according to claim 3, characterized in that: In step 3), in the presence of a base, the intermediate of formula 4 undergoes a Michael addition reaction with 2-acetylpyridine, and then ammonia water is added to carry out a ring-closing reaction; The conditions of the Michael addition reaction are: reacting at room temperature for 6 to 10 hours; The conditions of the ring-closing reaction are: reacting at a temperature of 70 to 90° C. for 16 to 32 hours.

7. The method for synthesizing a terpyridine zinc complex according to claim 3, characterized in that: In step 2), in the presence of a base, the brominated terpyridine compound and the boronic acid compound of formula 6 undergo a coupling reaction at 75 to 85° C. under the catalysis of a palladium catalyst for 30 to 60 hours.

8. The method for synthesizing a terpyridine zinc complex according to claim 3, characterized in that: The conditions of the coordination reaction are: reaction at a temperature of 60 to 70° C. for 18 to 32 hours.

9. The use of a terpyridine zinc complex according to claim 1 or 2, characterized in that: Used as photosensitizer or photocatalyst.

10. The use of a terpyridine zinc complex according to claim 9, characterized in that: The terpyridine zinc complex has the characteristic of generating singlet oxygen and superoxide free radicals under sunlight irradiation.

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