AIE type cyclic iridium-butyltin phenanthroline complex with adjustable luminescence color as well as preparation method and application of AIE type cyclic iridium-butyltin phenanthroline complex

Abstract

The invention discloses an aggregation-induced emission (AIE) type cyclic iridium-butyltin phenanthroline complex with adjustable luminescence color as well as a preparation method and anti-cancer application of the AIE type cyclic iridium-butyltin phenanthroline complex. The structural formula of the complex is shown as a formula (I), and C and N ligands are 2-(2, 4-difluorophenyl) pyridine, 2-phenylpyridine, 2-phenylquinoline, 2-(naphthalene-2-yl) quinoline and 3-(6-phenanthroline)-N, N-diphenyl aniline. By testing the growth inhibition rate of the target complex to human alveolar basal epithelial cancer cells (A549 cells) and comparing, the target complex shows potential anti-cancer activity. Besides, the target complex shows unique AIE characteristics, adjustable fluorescence emission with the wavelength of 540-680 nm is achieved, mitochondria of A549 lung cancer cells can be targeted, mitochondrial membrane potential is reduced, cell apoptosis is induced, and anticancer activity is shown.

Description

Technical Field

[0001] This invention relates to organometallic compounds, specifically to a tributyltin-cycloiridium imidazoline complex with tunable luminescence color and AIE properties, its preparation method, and its applications, belonging to the fields of fluorescent probes and pharmaceutical chemicals. Background Technology

[0002] Platinum-based drugs play a significant role in clinical cancer treatment, fully demonstrating the enormous potential of metal-based anticancer drugs in the field of chemotherapy. However, their significant drug resistance and toxicity have spurred the development of novel non-platinum-based metal-based anticancer drugs. Coord Chem Rev 2023, 490, 215231 Iridium complexes can exert anticancer effects by targeting the lysosomes and mitochondria of cancer cells, exhibiting a mechanism of action different from platinum-based drugs. They show good application potential as a possible alternative to platinum-based drugs. Chem Soc Rev 2023,52, 2790-2832 Iridium metal anticancer complexes are mainly divided into two types: semi-sandwich structure and cyclic metal structure. Inorg Chem 2023, 62, 3395−3408 Among them, iridium complexes with cyclic metallic structures are widely used in fields such as bioimaging, biosensing, and anticancer treatment due to their excellent photophysical properties. J Med Chem 2023, 66, 13731−13745 In addition, organotin compounds have also attracted much attention in the field of oncology due to their economical price and significant anti-cancer potential. Appl Organomet Chem 2018, 32, e4475. Due to concentration variations, both cycloiridium complexes and organotin compounds exhibit weak fluorescence or aggregation-induced fluorescence quenching (ACQ), which is highly detrimental to imaging studies such as subcellular tissue targeting. The discovery of aggregation-induced emission (AIE) effectively avoided fluorescence quenching caused by molecular aggregation. Compounds with AIE properties exhibit good fluorescence characteristics at high concentrations or in aggregated states. Chem Rev 2024, 124, 11242−11347 Therefore, fluorescent metal complexes with AIE properties are widely used in photocatalysis, light-emitting diodes, and bioimaging. ACS Cent Sci2020, 6, 1689−1712 However, in the development of anticancer drugs, metal anticancer complexes with AIE properties and multiple metal active centers are rare. Summary of the Invention

[0003] Therefore, this invention introduces tributyltin molecules with good anticancer potential into cycloiridium imidazoline-phenanthroline heteronuclear metal complexes to prepare butyltin-cycloiridium imidazoline-phenanthroline heteronuclear metal complexes with AIE properties. The synergistic effect of the cycloiridium complex and organotin compounds enhances the in vitro antiproliferative activity of the target complex against A549 lung cancer cells. Simultaneously, tunable fluorescence emission at wavelengths of 540–680 nm was achieved through screening and modification of peripheral ligands. Utilizing its AIE properties, its target location (mitochondria) in A549 lung cancer cells was detected, confirming its mechanism of inducing apoptosis in A549 lung cancer cells and exhibiting anticancer activity, making it a promising novel mitochondrial-targeted non-platinum metal anticancer drug.

[0004] An imidazophenanthroline benzoic acid compound, the structure of which is shown in formula (II): ; A cycloiridium imidazoline phenanthrene benzoic acid complex, the structure of which is shown in formula (III): ; In formula (III), the C and N ligands are selected from 2-(2,4-difluorophenyl)pyridine, 2-phenylpyridine, 2-phenylquinoline, 2-(naphth-2-yl)quinoline, and 3-(6-phenanthrodinyl)-N,N-diphenylaniline.

[0005] A tributyltin-cycloiridium imidazoline complex, the structure of which is shown in formula (I): ; In formula (I), the C and N ligands are selected from 2-(2,4-difluorophenyl)pyridine, 2-phenylpyridine, 2-phenylquinoline, 2-(naphth-2-yl)quinoline, and 3-(6-phenanthrodinyl)-N,N-diphenylaniline.

[0006] Furthermore, the chemical structural formulas of all target compounds of this invention are as follows: .

[0007] This invention provides a method for preparing the above-mentioned compound: 1,10-phenanthroline-5,6-dione, ammonium acetate, 3,5-difluoro-4-carboxybenzoic acid, p-nitroaniline, and glacial acetic acid are placed in a Schlenk flask and refluxed to obtain imidazophenanthroline benzoic acid compound (II). The imidazophenanthroline benzoic acid compound (II) reacts with a dimer of basic iridium (Ir1-Ir5) at room temperature to obtain the cyclic iridium imidazophenanthroline benzoic acid complex (III) shown, which is then refluxed with hexabutyltin oxide (Bu6Sn2O) to obtain the target complex (I) shown. The specific reaction route is as follows: .

[0008] Furthermore, when the compound is of formula (IrSn1), it is prepared by the following method: (1) 220 mg of 1,10-phenanthroline-5,6-dione, 3.85 g of ammonium acetate, 186 mg of 3,5-difluoro-4-carboxybenzoic acid, 138 mg of p-nitroaniline and 10 mL of glacial acetic acid were placed in a 100 mL Schlenk flask and refluxed for 8 h under nitrogen protection. The reaction was quenched with ice water after cooling to room temperature. The mixture was filtered and washed three times with ethanol to obtain imidazophenanthroline benzoic acid compound (II). (2) 99.4 mg of imidazophenanthroline benzoic acid compound (II) and 120.3 mg of basic iridium dimer (Ir1) were placed in a 100 mL Schlenk flask, and 20 mL of anhydrous methanol was injected. The mixture was stirred at room temperature for 24 h under a nitrogen atmosphere, and the reaction progress was monitored by thin-layer chromatography (TLC). The solvent was removed under reduced pressure, and the cycloiridium imidazophenanthroline benzoic acid complex (IrA1) was purified by column chromatography (dichloromethane:methanol = 20:1, v / v). (3) 33.4 mg of hexabutyldistannoxane and 96.8 mg of cycloiridium imidazoline benzoic acid complex (IrA1) were added to a Dean-Stark apparatus, and 100 mL of a mixed solvent of benzene and ethanol (volume ratio 2:1) was injected. The mixture was refluxed for 8 h. The solvent was removed under reduced pressure, and the target complex (IrSn1) was obtained by recrystallization (methanol: ether = 1:5, volume ratio).

[0009] Furthermore, when the compound is of formula (IrSn2), it is prepared by the following method: (1) 220 mg of 1,10-phenanthroline-5,6-dione, 3.85 g of ammonium acetate, 186 mg of 3,5-difluoro-4-carboxybenzoic acid, 138 mg of p-nitroaniline and 10 mL of glacial acetic acid were placed in a 100 mL Schlenk flask and refluxed for 8 h under nitrogen protection. The reaction was quenched with ice water after cooling to room temperature. The mixture was filtered and washed three times with ethanol to obtain imidazophenanthroline benzoic acid compound (II). (2) 99.4 mg of imidazophenanthroline benzoic acid compound (II) and 107.2 mg of basic iridium dimer (Ir2) were placed in a 100 mL Schlenk flask, and 20 mL of anhydrous methanol was injected. The mixture was stirred at room temperature for 24 h under a nitrogen atmosphere, and the reaction progress was monitored by thin-layer chromatography (TLC). The solvent was removed under reduced pressure, and the cycloiridium imidazophenanthroline benzoic acid complex (IrA2) was purified by column chromatography (dichloromethane:methanol = 20:1, v / v). (3) 33.4 mg of hexabutyldistannoxane and 88.8 mg of cycloiridium imidazoline benzoic acid complex (IrA2) were added to a Dean-Stark apparatus, and 100 mL of a mixed solvent of benzene and ethanol (volume ratio 2:1) was injected. The mixture was refluxed for 8 h. The solvent was removed under reduced pressure, and the target complex (IrSn2) was obtained by recrystallization (methanol: ether = 1:5, volume ratio).

[0010] Furthermore, when the compound is of formula (IrSn3), it is prepared by the following method: (1) 220 mg of 1,10-phenanthroline-5,6-dione, 3.85 g of ammonium acetate, 186 mg of 3,5-difluoro-4-carboxybenzoic acid, 138 mg of p-nitroaniline and 10 mL of glacial acetic acid were placed in a 100 mL Schlenk flask and refluxed for 8 h under nitrogen protection. The reaction was quenched with ice water after cooling to room temperature. The mixture was filtered and washed three times with ethanol to obtain imidazophenanthroline benzoic acid compound (II). (2) 99.4 mg of imidazophenanthroline benzoic acid compound (II) and 127.2 mg of basic iridium dimer (Ir3) were placed in a 100 mL Schlenk flask, and 20 mL of anhydrous methanol was injected. The mixture was stirred at room temperature under a nitrogen atmosphere for 24 h, and the reaction progress was monitored by thin-layer chromatography (TLC). The solvent was removed under reduced pressure, and the cycloiridium imidazophenanthroline benzoic acid complex (IrA3) was purified by column chromatography (dichloromethane:methanol = 20:1, v / v). (3) 33.4 mg of hexabutyldistannoxane and 101.5 mg of cycloiridium imidazoline benzoic acid complex (IrA3) were added to a Dean-Stark apparatus, and 100 mL of a mixed solvent of benzene and ethanol (volume ratio 2:1) was injected. The mixture was refluxed for 8 h. The solvent was removed under reduced pressure, and the target complex (IrSn3) was obtained by recrystallization (methanol: ether = 1:5, volume ratio).

[0011] Furthermore, when the compound is of formula (IrSn4), it is prepared by the following method: (1) 220 mg of 1,10-phenanthroline-5,6-dione, 3.85 g of ammonium acetate, 186 mg of 3,5-difluoro-4-carboxybenzoic acid, 138 mg of p-nitroaniline and 10 mL of glacial acetic acid were placed in a 100 mL Schlenk flask and refluxed for 8 h under nitrogen protection. The reaction was quenched with ice water after cooling to room temperature. The mixture was filtered and washed three times with ethanol to obtain imidazophenanthroline benzoic acid compound (II). (2) 99.4 mg of imidazophenanthroline benzoic acid compound (II) and 146.0 mg of basic iridium dimer (Ir4) were placed in a 100 mL Schlenk flask, and 20 mL of anhydrous methanol was injected. The mixture was stirred at room temperature for 24 h under a nitrogen atmosphere, and the reaction progress was monitored by thin-layer chromatography (TLC). The solvent was removed under reduced pressure, and the cycloiridium imidazophenanthroline benzoic acid complex (IrA4) was purified by column chromatography (dichloromethane:methanol = 20:1, v / v). (3) 33.4 mg of hexabutyldistannoxane and 112.7 mg of cycloiridium imidazoline benzoic acid complex (IrA4) were added to a Dean-Stark apparatus, and 100 mL of a mixed solvent of benzene and ethanol (volume ratio 2:1) was injected. The mixture was refluxed for 8 h. The solvent was removed under reduced pressure, and the target complex (IrSn4) was obtained by recrystallization (methanol: ether = 1:5, volume ratio).

[0012] Furthermore, when the compound is of formula (IrSn5), it is prepared by the following method: (1) 220 mg of 1,10-phenanthroline-5,6-dione, 3.85 g of ammonium acetate, 186 mg of 3,5-difluoro-4-carboxybenzoic acid, 138 mg of p-nitroaniline and 10 mL of glacial acetic acid were placed in a 100 mL Schlenk flask and refluxed for 8 h under nitrogen protection. The reaction was quenched with ice water after cooling to room temperature. The mixture was filtered and washed three times with ethanol to obtain imidazophenanthroline benzoic acid compound (II). (2) 99.4 mg of imidazophenanthroline benzoic acid compound (II) and 193.3 mg of basic iridium dimer (Ir5) were placed in a 100 mL Schlenk flask, and 20 mL of anhydrous methanol was injected. The mixture was stirred at room temperature under a nitrogen atmosphere for 24 h, and the reaction progress was monitored by thin-layer chromatography (TLC). The solvent was removed under reduced pressure, and the cycloiridium imidazophenanthroline benzoic acid complex (IrA5) was purified by column chromatography (dichloromethane:methanol = 20:1, v / v). (3) 33.4 mg of hexabutyldistannoxane and 137.0 mg of cycloiridium imidazoline benzoic acid complex (IrA5) were added to a Dean-Stark apparatus, and 100 mL of a mixed solvent of benzene and ethanol (volume ratio 2:1) was injected. The mixture was refluxed for 8 h. The solvent was removed under reduced pressure, and the target complex (IrSn5) was obtained by recrystallization (methanol: ether = 1:5, volume ratio).

[0013] This invention provides an application of the tributyltin-cycloiridium imidazoline complex prepared by the above method in the field of preparing metal-based anticancer drugs. The complex exhibits potential antiproliferative activity against A549 lung cancer cells, providing a fundamental structural platform for the design and development of novel multi-core metal-based anticancer drugs. Simultaneously, the target complex has tunable color (540~680 nm) and aggregation-induced emission (AIE) properties, which facilitates its use as a probe to detect drug targeting within cancer cells.

[0014] The beneficial effects of this invention are as follows: (1) This invention proposes a synergistic anticancer design of tributyltin and cycloiridium complexes. Compared with single cycloiridium complexes and organotin compounds, the target product effectively improves the overall anticancer activity, demonstrating its synergistic anticancer effect; (2) By screening and modifying peripheral ligands, the invention regulates the conjugation area and electron absorption and donation properties of the target complex, achieving tunable fluorescence emission of 540~680 nm and possessing aggregation-induced emission (AIE) properties, which facilitates targeted research and can be used as a mitochondrial-targeted probe to further explore its anti-cancer mechanism. Attached Figure Description

[0015] Figure 1 The 1H NMR spectrum of the imidazophenanthroline benzoic acid compound of this invention; Figure 2 The proton NMR spectrum of the compound IrA1 of this invention; Figure 3 The proton NMR spectrum of the compound IrA2 of this invention; Figure 4 The proton NMR spectrum of the compound IrA3 of this invention; Figure 5 The proton NMR spectrum of the compound IrA4 of this invention; Figure 6 The proton NMR spectrum of compound IrA5 of this invention; Figure 7 The proton NMR spectrum of the compound IrSn1 of this invention; Figure 8 The proton NMR spectrum of the compound IrSn2 of this invention; Figure 9 The proton NMR spectrum of the compound IrSn3 of this invention; Figure 10 The proton NMR spectrum of the compound IrSn4 of this invention; Figure 11 The proton NMR spectrum of the compound IrSn5 of this invention; Figure 12 The fluorescence spectra of the compounds IrSn1~IrSn5 of this invention are shown below. Figure 13 The fluorescence spectrum of the compound IrSn5 of this invention in an acetonitrile / water mixed system is shown. Figure 14 The fluorescence spectrum of compound IrSn5 in the glycerol / methanol mixture is shown below. Figure 15 This is a diagram showing the subcellular tissue targeting assay of the compound IrSn5 of this invention in A549 lung cancer cells; Figure 16 This is a graph showing the mitochondrial membrane potential of A549 lung cancer cells treated with the compound IrSn5 of this invention. Figure 17 This is a graph showing the intracellular reactive oxygen species (ROS) level in A549 lung cancer cells after treatment with the compound IrSn5 of this invention. Figure 18 This is a flow cytometry diagram showing the apoptosis induced in A549 lung cancer cells by the compound IrSn5 of this invention. Detailed Implementation

[0016] The present invention is further illustrated by examples of some representative compounds, but these descriptions do not limit the invention.

[0017] The starting compounds used in the synthesis of these compounds are commercial products or can be prepared from known synthetic methods. Methods for preparing all organic compounds are readily available in the literature and are fundamental and obvious to synthetic chemists. Therefore, the following descriptions of synthetic methods can be considered detailed and specific.

[0018] Example 1 220 mg of 1,10-phenanthroline-5,6-dione, 3.85 g of ammonium acetate, 186 mg of 3,5-difluoro-4-carboxybenzoic acid, 138 mg of p-nitroaniline, and 10 mL of glacial acetic acid were placed in a 100 mL Schlenk flask and refluxed for 8 h under nitrogen protection. The reaction was quenched with ice water after cooling to room temperature. The mixture was filtered and washed three times with ethanol to give 385.1 mg of imidazophenanthroline benzoic acid compound (II) (yield 77.5%). The characterization spectrum is shown below. Figure 1 As shown: 1 H NMR (500 MHz, DMSO- d 6) δ 14.21 (s,1H), 9.11 – 9.05 (m, 3H), 8.94 – 8.89 (m, 3H), 7.85 (dd, J = 13.4, 6.4 Hz, 6H).Elemental analysis: calcd (%) for C 28 H 21 F2N5O4, C, 63.51; H, 4.00; O, 12.09; N, 13.23; Found: C, 63.81; H, 4.10; O, 11.99; N, 13.13. Example 2 99.4 mg of imidazophenanthroline benzoic acid compound (II) and 120.3 mg of basic iridium dimer (Ir1) were placed in a 100 mL Schlenk flask, and 20 mL of anhydrous methanol was injected. The mixture was stirred at room temperature for 24 h under a nitrogen atmosphere, and the reaction progress was monitored by thin-layer chromatography (TLC). The solvent was removed under reduced pressure, and the product was purified by column chromatography (dichloromethane:methanol = 20:1, v / v) to obtain 106.3 mg of the cycloiridium imidazophenanthroline benzoic acid complex (IrA1) (yield 87.5%). The characterization chromatogram is shown below. Figure 2 As shown: 1 H NMR (500MHz, DMSO-d6) δ 9.08 – 9.04 (m, 2H), 8.91 (dd, J = 8.1, 1.6 Hz, 1H), 8.61 (d, J =8.9 Hz, 2H), 8.51 (d, J = 8.9 Hz, 2H), 8.41 (d, J = 4.8 Hz, 2H), 8.36 (d, J = 7.9Hz, 2H), 8.07 (dd, J = 8.2, 5.2 Hz, 2H), 7.85 (dd, J = 8.1, 4.2 Hz, 1H), 7.82 (d, J = 8.0 Hz, 2H), 7.77 (d, J = 8.5 Hz, 1H), 7.66 (d, J = 8.8 Hz, 2H), 7.25 (d, J =7.7 Hz, 2H), 7.22 (d, J = 7.9 Hz, 2H), 7.21 – 7.18 (m, 2H), 7.17 (s, 1H), 6.87(dt, J = 8.1, 4.3 Hz, 4H), 6.53 (d, J = 7.6 Hz, 2H). Elemental analysis: calcd(%) for C 48 H 25O4N7PF 12 Ir, C, 47.45; H, 2.07; O, 5.27; N, 8.07; Found: C, 47.75; H, 2.17; O, 5.17; N, 7.97. Example 3 99.4 mg of imidazophenanthroline benzoic acid compound (II) and 107.2 mg of basic iridium dimer (Ir2) were placed in a 100 mL Schlenk flask, and 20 mL of anhydrous methanol was injected. The mixture was stirred at room temperature for 24 h under a nitrogen atmosphere, and the reaction progress was monitored by thin-layer chromatography (TLC). The solvent was removed under reduced pressure, and the product was purified by column chromatography (dichloromethane:methanol = 20:1, v / v) to obtain 99.3 mg of the cycloiridium imidazophenanthroline benzoic acid complex (IrA2) (yield 86.9%). The characterization spectrum is shown below. Figure 3 As shown: 1 H NMR (500 MHz, DMSO-d6) δ 8.40 (d, J = 8.7 Hz, 1H), 8.19 (d, J = 8.7 Hz, 2H), 8.07 (d, J = 8.7 Hz, 1H), 8.01 (d, J = 8.4 Hz, 1H), 7.96 (d, J = 8.0 Hz, 1H), 7.78 – 7.73 (m, 1H), 7.56 (t, J = 7.5 Hz, 1H), 7.36 (t, J = 7.8 Hz, 4H), 7.12 (t, J = 7.6 Hz, 6H), 7.08 (d, J = 8.7 Hz, 2H). Elemental analysis: calcd (%) for C 48 H 29 O4N7PF8Ir, C, 50.44; H, 2.56; O, 5.60; N, 8.58; Found: C, 50.74; H, 2.66; O, 5.50; N, 8.48. Example 4 99.4 mg of imidazophenanthroline benzoic acid compound (II) and 127.2 mg of basic iridium dimer (Ir3) were placed in a 100 mL Schlenk flask, and 20 mL of anhydrous methanol was injected. The mixture was stirred at room temperature for 24 h under a nitrogen atmosphere, and the reaction progress was monitored by thin-layer chromatography (TLC). The solvent was removed under reduced pressure, and the product was purified by column chromatography (dichloromethane:methanol = 20:1, v / v) to obtain 106.5 mg of the cycloiridium imidazophenanthroline benzoic acid complex (IrA3) (yield 85.7%). The characterization spectrum is shown below. Figure 4 As shown: 1 H NMR (500MHz, DMSO-d6) δ 9.23 (d, J = 8.1 Hz, 3H), 8.27 (d, J = 8.2 Hz, 4H), 8.17 (d, J =5.0 Hz, 3H), 8.08 (dd, J = 8.2, 5.1 Hz, 3H), 7.96 (d, J = 7.8 Hz, 3H), 7.89 (t, J =7.8 Hz, 4H), 7.73 (d, J = 8.4 Hz, 4H), 7.53 (d, J = 5.8 Hz, 3H), 7.07 (t, J = 7.5Hz, 3H), 7.01 – 6.94 (m, 7H), 6.31 (d, J = 7.5 Hz, 3H). Elemental analysis:calcd (%) for C 56 H 33 O4N7PF8Ir, C, 54.11; H, 2.68; O, 5.15; N, 7.89; Found: C, 54.41; H, 2.78; O, 5.05; N, 7.79. Example 5 99.4 mg of imidazophenanthroline benzoic acid compound (II) and 146.0 mg of basic iridium dimer (Ir4) were placed in a 100 mL Schlenk flask, and 20 mL of anhydrous methanol was injected. The mixture was stirred at room temperature for 24 h under a nitrogen atmosphere, and the reaction progress was monitored by thin-layer chromatography (TLC). The solvent was removed under reduced pressure, and the product was purified by column chromatography (dichloromethane:methanol = 20:1, v / v) to give 118.3 mg of the cycloiridium imidazophenanthroline benzoic acid complex (IrA4) (yield 88.1%). The characterization chromatogram is shown below. Figure 5 As shown:1 H NMR (500MHz, DMSO-d6) δ 9.07 (s, 1H), 9.04 – 9.01 (m, 1H), 8.86 (d, J = 8.9 Hz, 1H), 8.62 (d, J = 8.9 Hz, 1H), 8.55 – 8.53 (m, 1H), 8.08 – 8.00 (m, 2H), 7.86 (d, J =7.8 Hz, 1H), 7.80 (d, J = 8.3 Hz, 1H), 7.38 – 7.33 (m, 2H), 7.30 – 7.25 (m,2H), 7.21 (d, J = 8.2 Hz, 1H), 6.97 (s, 1H), 6.88 – 6.84 (m, 1H). Elementalanalysis: calcd (%) for C 64 H 37 O4N7PF8Ir, C, 57.23; H, 2.78; O, 4.76; N, 7.30; Found: C, 57.53; H, 2.88; O, 4.66; N, 7.20. Example 6 99.4 mg of imidazophenanthroline bidentate ligand (II) and 193.3 mg of basic iridium dimer (Ir5) were placed in a 100 mL Schlenk flask, and 20 mL of anhydrous methanol was injected. The mixture was stirred at room temperature for 24 h under a nitrogen atmosphere, and the reaction progress was monitored by thin-layer chromatography (TLC). The solvent was removed under reduced pressure, and the product was purified by column chromatography (dichloromethane:methanol = 20:1, v / v) to obtain 136.7 mg of the cycloiridium imidazophenanthroline benzoic acid complex (IrA5) (yield 89.2%). The characterization chromatogram is shown below. Figure 6 As shown: 1 H NMR (500 MHz, DMSO-d6) δ 9.13 – 9.10 (m, 2H), 9.07 (d, J = 8.0 Hz, 2H), 8.89 (dd, J = 8.2, 0.9Hz, 2H), 8.64 – 8.58 (m, 2H), 8.36(d, J = 7.8 Hz, 2H), 8.25 (d, J = 9.1 Hz, 2H), 8.01 (dd, J= 8.1, 5.3 Hz, 2H), 7.95 – 7.85 (m, 5H), 7.75 (d, J = 8.3 Hz, 2H), 7.62 (d, J = 8.6 Hz, 2H), 7.30 (dd, J = 11.4, 4.0 Hz, 2H), 7.00 (d, J = 10.3 Hz, 4H), 6.98 (s, 4H), 6.96 (s, 3H), 6.88 (d, J = 7.5 Hz, 9H), 6.84 (t, J = 7.3 Hz, 5H), 6.72 (dd, J = 8.9, 2.4 Hz, 2H), 6.48 (d, J = 2.4 Hz, 2H). Elemental analysis: calcd (%) for C 88 H 55 O4N9PF8Ir, C, 63.00; H, 3.30; O, 3.81; N, 7.51; Found: C, 63.30; H, 3.40; O, 3.71; N, 7.41. Example 7 33.4 mg of hexabutyldistannoxane and 96.8 mg of the cycloiridium imidazophenanthroline benzoic acid complex (IrA1) were added to a Dean-Stark apparatus, followed by 100 mL of a benzene and ethanol mixture (2:1 v / v), and the mixture was refluxed for 8 h. The solvent was removed under reduced pressure, and the mixture was recrystallized (methanol:diethyl ether = 1:5 v / v) to obtain 68.0 mg of the target complex (IrSn1) (80.7% yield). The characterization spectrum is shown below. Figure 7 As shown: 1 H NMR (500 MHz, DMSO-d6) δ 9.20 (d, J = 8.0 Hz, 2H), 8.31 (d, J = 8.7Hz, 2H), 8.23 ​​(d, J = 4.6 Hz, 2H), 8.08 (dd, J = 8.2, 5.1 Hz, 3H), 7.99 (dd, J =12.0, 4.4 Hz, 3H), 7.69 (d, J = 8.4 Hz, 3H), 7.59 (d,J = 5.7 Hz, 2H), 7.09 –7.03 (m, 3H), 7.03 – 6.99 (m, 2H), 5.73 (dd, J = 8.3, 2.3 Hz, 2H), 1.66 – 1.60(m, 6H), 1.33 (d, J = 7.3 Hz, 6H), 1.21 – 1.13 (m, 6H), 0.89 (d, J = 7.3 Hz, 9H).Elemental analysis: calcd (%) for C 60 H 51 O4N7PF 12 IrSn, C, 47.92; H, 3.42; O, 4.26; N, 6.52; Found: C, 48.22; H, 3.52; O, 4.16; N, 6.42. Example 8 33.4 mg of hexabutyldistannoxane and 88.8 mg of the cycloiridium imidazophenanthroline benzoic acid complex (IrA2) were added to a Dean-Stark apparatus, followed by 100 mL of a benzene and ethanol mixture (2:1 v / v), and the mixture was refluxed for 8 h. The solvent was removed under reduced pressure, and the product was recrystallized (methanol:diethyl ether = 1:5 v / v) to obtain 65.5 mg of the target complex (IrSn2) (81.6% yield). The characterization spectrum is shown below. Figure 8 As shown: 1 H NMR (500 MHz, MeOD) δ 9.14 (d, J = 8.1 Hz, 2H), 8.34 (dd, J = 5.1, 1.1 Hz, 2H), 8.13 (d, J = 8.3 Hz, 2H), 7.95 (dd, J = 8.3, 5.1 Hz, 3H), 7.87 (d, J =7.8 Hz, 2H), 7.83 – 7.74 (m, 5H), 7.51 (d, J = 5.7 Hz, 2H), 7.08 (dd, J = 11.0, 4.1 Hz, 3H), 6.96 (dd, J = 10.7, 4.2 Hz, 3H), 6.91 (dd, J= 9.7, 3.5 Hz, 2H), 6.41 (d, J = 7.5 Hz, 2H), 1.68 (d, J = 7.3 Hz, 6H), 1.40 (d, J = 6.3 Hz, 6H), 1.28(m, 6H), 0.94 (d, J = 7.3 Hz, 9H). Elemental analysis: calcd (%) forC 60 H 55 O4N7PF8IrSn, C, 50.32; H, 3.87; O, 4.47; N, 6.85; Found: C, 50.62; H, 3.97; O, 4.37; N, 6.75. Example 9 33.4 mg of hexabutyldistannoxane and 101.5 mg of the cycloiridium imidazophenanthroline benzoic acid complex (IrA3) were added to a Dean-Stark apparatus, and 100 mL of a benzene and ethanol mixture (2:1 v / v) was injected. The mixture was refluxed for 8 h. The solvent was removed under reduced pressure, and the product was recrystallized (methanol:diethyl ether = 1:5 v / v) to give 67.1 mg of the target complex (IrSn3) (77.9% yield). The characterization spectrum is shown below. Figure 9 As shown: 1 H NMR (500 MHz, MeOD) δ 8.98 (d, J = 8.2 Hz, 2H), 8.57 (d, J = 5.1Hz, 2H), 8.44 (d, J = 8.8 Hz, 2H), 8.34 (d, J = 8.8 Hz, 2H), 8.24 (d, J = 8.0 Hz, 2H), 7.94 (dd, J = 8.3, 5.2 Hz, 3H), 7.69 (t, J = 8.3 Hz, 5H), 7.30 (d, J = 9.0 Hz, 2H), 7.21 (dd, J = 15.8, 8.0 Hz, 5H), 6.88 – 6.78 (m, 5H), 6.63 (d, J = 7.7 Hz, 2H), 1.66 (d, J = 7.6 Hz, 6H), 1.40 (d,J = 7.3 Hz, 6H), 1.28 (m, 6H), 0.93 (m,9H). Elemental analysis: calcd (%) for C 68 H 59 O4N7PF8IrSn, C, 53.31; H, 3.88; O, 4.18; N, 6.40; Found: C, 53.61; H, 3.98; O, 4.08; N, 6.30. Example 10 33.4 mg of hexabutyldistannoxane and 112.7 mg of the cycloiridium imidazoline benzoic acid complex (IrA4) were added to a Dean-Stark apparatus, followed by 100 mL of a benzene and ethanol mixture (2:1 v / v), and the mixture was refluxed for 8 h. The solvent was removed under reduced pressure, and the product was recrystallized (methanol:diethyl ether = 1:5 v / v) to give 76.6 mg of the target complex (IrSn4) (83.8% yield). The characterization spectrum is shown below. Figure 10 As shown: 1H NMR (500 MHz, DMSO-d6) δ 9.07 (s, 2H), 9.03 (d, J = 8.1 Hz, 2H), 8.87 (d, J = 9.0 Hz, 2H), 8.62 (d, J = 8.9 Hz, 2H), 8.55 (d, J = 4.7 Hz, 2H),8.15 – 7.96 (m, 5H), 7.86 (d, J = 8.0 Hz, 2H), 7.81 (dd, J = 13.2, 6.4 Hz, 2H),7.38 – 7.34 (m, 4H), 7.27 (dd, J = 15.2, 7.6 Hz, 4H), 7.21 (d, J = 8.6 Hz, 3H),7.10 (s, 1H), 6.99 (d, J = 15.2 Hz, 3H), 6.87 (dd, J = 11.8, 4.0 Hz, 2H), 1.60(d, J = 7.6 Hz, 6H), 1.31 (d, J= 7.2 Hz, 6H), 1.20 – 1.13 (m, 6H), 0.88 (m, 9H).Elemental analysis: calcd (%) for C 76 H 63 O4N7PF8IrSn, C, 55.92; H, 3.89; O, 3.92; N, 6.01; Found: C, 56.22; H, 3.99; O, 3.82; N, 5.91. Example 11 33.4 mg of hexabutyldistannoxane and 137.0 mg of the cycloiridium imidazophenanthroline benzoic acid complex (IrA5) were added to a Dean-Stark apparatus, and 100 mL of a benzene and ethanol mixture (2:1 v / v) was injected. The mixture was refluxed for 8 h. The solvent was removed under reduced pressure, and the product was recrystallized (methanol:diethyl ether = 1:5 v / v) to give 95.2 mg of the target complex (IrSn5) (85.4% yield). The characterization spectrum is shown below. Figure 11 As shown: 1 H NMR (500 MHz, DMSO-d6) δ 9.13 (dd, J = 14.6, 6.4 Hz, 4H), 8.92(d, J = 8.2 Hz, 2H), 8.66 (d, J = 8.0 Hz, 2H), 8.40 (d, J = 8.0 Hz, 2H), 8.30 (d, J =9.0 Hz, 2H), 8.07 – 8.02 (m, 2H), 7.96 (dt, J = 14.9, 7.2 Hz, 5H), 7.66 (t, J =10.2 Hz, 4H), 7.35 (t, J = 7.6 Hz, 2H), 7.04 (dd, J = 15.3, 7.3 Hz, 12H), 6.93(d, J = 7.5 Hz, 8H), 6.89 (t, J = 7.3 Hz, 5H), 6.77 (dd, J = 8.9, 2.3 Hz, 2H), 6.53(d, J = 2.4 Hz, 2H), 1.65 (dd, J= 4.8, 1.3 Hz, 6H), 1.36 (d, J = 7.3 Hz, 6H), 1.20(dd, J = 12.4, 10.4 Hz, 6H), 0.91 (d, J = 7.0 Hz, 9H). Elemental analysis: calcd(%) for C 100 H 81 O4N9PF8IrSn, C, 61.07; H, 4.15; O, 3.25; N, 6.41; Found: C, 61.37; H, 4.25; O, 3.15; N, 6.31. Example 12 The experimental steps for the antiproliferative effect of the target complex on A549 lung cancer cells are as follows: (1) Preparation of drug solution: The complex is dissolved in dimethyl sulfoxide (DMSO) and diluted with cell culture medium to a gradient concentration; (2) MTT assay for cell growth inhibition rate: 1) Seed the cell suspension into a 96-well culture plate, incubate at 310 K with 5% CO2 for 24 h, inject the drug solution, and continue incubation for another 24 h; 2) Add 15 μL Incubate with 5 mg / mL MTT solution for another 4 hours. 3) Wash away the culture medium and add 100 μL The DMSO was shaken in the dark for 15 minutes, and its optical density value (570nm) was measured by an ELISA reader. 4) Each experiment was repeated three times, IC 50 =mean ± SEM.

[0019] Table 1 shows the numerical values ​​of the inhibition rates of the target compound (I) and cisplatin on the growth of human alveolar basal epithelial carcinoma cells (A549 cells).

[0020] Table 1. Growth Inhibition Rate of A549 As shown in Table 1, under the same conditions, the antiproliferative activities of complexes IrSn1, IrSn2, and IrSn5 against A549 lung cancer cells were all superior to cisplatin, especially IrSn5, whose activity was almost 7 times that of cisplatin. Furthermore, compared to the low activity (IC50) of the cycloiridium imidazoline benzoic acid complex (III), [the antiproliferative activity was significantly higher]. 50 Values ​​> 100 μThe introduction of tributyltin molecule (M) effectively enhanced the antiproliferative activity of the target complex (I), demonstrating its good synergistic anticancer effect.

[0021] Example 13 Fluorescence spectroscopy determined the target complex (I) in DMSO (2.0 × 10⁻⁶) light. -5 The emission spectrum of M). This was achieved by screening and modulating the conjugated area (C, N) and electron-donating / withdrawing properties (F) of the peripheral ligands. - NO2 - This achieved coverage of fluorescence emission from yellow light to red light (540~680 nm) from IrSn1 to IrSn5. Figure 12 Considering the long fluorescence emission (strong penetration ability) and optimal in vitro anti-proliferative activity, IrSn5 was selected as a model to test the luminescence properties of this type of complex in an acetonitrile / water mixture. Figure 13 ).

[0022] The solubility of IrSn5 in the mixed solution decreased with increasing water (poor solvent) content. IrSn5 exhibited a weak fluorescence peak at lower water contents (<60%), attributed to the dispersion of the complex and internal molecular rotation, leading to nonradiative decay and weak fluorescence emission. However, at higher water contents (>60%), this behavior was suppressed, and fluorescence emission was enhanced, validating the AIE characteristics of IrSn5. Furthermore, in the methanol-glycerol mixed solution, the fluorescence intensity of IrSn5 gradually increased with increasing glycerol content. Figure 14 This is because as the glycerol content increases, the viscosity of the mixture increases, which inhibits the free rotation of IrSn5 molecules and enhances fluorescence, indicating that intramolecular rotation restriction is the essential reason why the complex exhibits AIE properties.

[0023] Example 14 Using the AIE properties of IrSn5, confocal microscopy was employed to detect subcellular tissue targeting of IrSn5 in A549 lung cancer cells. Lyso Tracker Red DND-99 (LTRD) and Mito Tracker Deep Red (MTDR) were used as fluorescent probes for lysosomes and mitochondria, respectively. A549 cells and IrSn5 (10 μ After co-incubating at 37 °C for 1 h, the probe (500 nM) was added and stained for 30 min. The cell plate was then rinsed three times with PBS buffer (pH: ~7.2) before photographing and detection. Figure 15The excitation wavelengths for LTRD, MTDR, and IrSn5 were 594, 644, and 405 nm, respectively, and the collection wavelengths were 645±20, 690±25, and 605±20 nm, respectively. The co-localization coefficients of IrSn5 in mitochondria and lysosomes were found to be 0.79 and 0.13, respectively, confirming that the target compound primarily targets the mitochondria of A549 lung cancer cells.

[0024] Example 15 The mitochondrial membrane potential changes in A549 cells after incubation with IrSn5 for a period of time were detected by flow cytometry using the 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazole carbonyl cyanine iodide (JC-1) probe. Under normal conditions, when the mitochondrial membrane potential is high, JC-1 exists in a polymerized state and exhibits red fluorescence. Conversely, JC-1 exists in monomeric form and exhibits green fluorescence. Figure 16 As shown, with the increase of IrSn5 concentration, the proportion of red fluorescence decreases while the proportion of green fluorescence increases significantly. When the IrSn5 concentration increases from 0.5 × IC50, the proportion of green fluorescence increases significantly. 50 Increased to 2.0×IC 50 At that time, the proportion of A549 lung cancer cells with mitochondrial membrane depolarization increased by 17.2%, confirming the decrease in mitochondrial membrane potential inside A549 cells after IrSn5 treatment.

[0025] Example 16 Reactive oxygen species (ROS) are byproducts of intracellular aerobic metabolism and are closely related to the cellular environment. Excessive accumulation of intracellular ROS can disrupt the distribution of membrane proteins, induce enzyme inactivation, and ultimately lead to apoptosis. The intracellular ROS levels in A549 lung cancer cells incubated with IrSn5 were detected using the DCFH-DA probe. Figure 17 As shown, intracellular ROS levels increased in a concentration-dependent manner. Compared to the control group, when the concentration increased to 1.0 × IC50, the ROS levels increased significantly. 50 At that time, the intracellular ROS level of A549 cells increased by 28.6 times, further confirming that IrSn5 can lead to the accumulation of intracellular ROS in A549 lung cancer cells.

[0026] Example 17 Apoptosis is a genetically controlled, ordered programmed cell death process, often accompanied by oxidative damage. A549 lung cancer cells were stained with Annexin V-FITC / PI probes, and IrSn5-induced apoptosis in A549 cells was detected by flow cytometry. Figure 18 As shown, the proportion of apoptotic cells increased in a dose-dependent manner. Compared with the control, when the concentration increased to 1.0 × IC50, the proportion of apoptotic cells increased. 50At that time, the apoptosis rate of IrSn5 (early apoptosis + late apoptosis) increased by 19.9%, especially early apoptosis (17.2%), while the cell survival rate of the control group was close to 90%. This confirms that IrSn5 targets mitochondria in A549 cells, reduces mitochondrial membrane potential, leads to the accumulation of reactive oxygen species in A549 lung cancer cells, and ultimately induces apoptosis, demonstrating an active anti-cancer mechanism.

Claims

1. An imidazophenanthroline benzoic acid compound, the structure of which is shown in formula (II): 。 2. A method for preparing the imidazophenanthroline benzoic acid compound according to claim 1, characterized in that, Includes the following steps: The reaction of 1,10-o-diazaphenanthroline-5,6-dione, 3,5-difluoro-4-aldehyde benzoic acid, and 4-nitroaniline yields the compound shown in formula (II). The specific reaction route is as follows: 。 3. A cycloiridium imidazoline benzoic acid complex, the structure of which is shown in formula (III): ； In formula (III), C and N are 2-(2,4-difluorophenyl)pyridine, 2-phenylpyridine, 2-phenylquinoline, 2-(naphth-2-yl)quinoline, and 3-(6-phenanthrodinyl)-N,N-diphenylaniline.

4. The cycloiridium imidazoline phenanthrene benzoic acid complex according to claim 3, characterized in that, In formula (III), when the C,N ligand is 2-(2,4-difluorophenyl)pyridine, the specific structural formula is shown in formula IrA1; when the C,N ligand is 2-phenylpyridine, the specific structural formula is shown in formula IrA2; when the C,N ligand is 2-phenylquinoline, the specific structural formula is shown in formula IrA3; when the C,N ligand is 2-(naphthyl-2-yl)quinoline, the specific structural formula is shown in formula IrA4; and when the C,N ligand is 3-(6-phenanthrolidyl)-N,N-diphenylaniline, the specific structural formula is shown in formula IrA5. 。 5. A method for preparing the cycloiridium imidazoline phenanthrene benzoic acid complex according to claim 3 or 4, characterized in that, Includes the following steps: The imidazophenanthroline benzoic acid compound shown in formula (II) reacts with the dimer of the basic iridium (Ir1-Ir5) to obtain the complex shown in formula (III), and the specific reaction route is as follows: 。 6. A tributyltin-cycloiridium imidazoline complex, the structure of which is shown in formula (I): ； In formula (I), C and N are selected from 2-(2,4-difluorophenyl)pyridine, 2-phenylpyridine, 2-phenylquinoline, 2-(naphth-2-yl)quinoline, and 3-(6-phenanthrodinyl)-N,N-diphenylaniline.

7. The tributyltin-cycloiridium imidazoline complex according to claim 6, characterized in that, In formula (I), when the C,N ligand is 2-(2,4-difluorophenyl)pyridine, the specific structural formula is shown in formula IrSn1; when the C,N ligand is 2-phenylpyridine, the specific structural formula is shown in formula IrSn2; when the C,N ligand is 2-phenylquinoline, the specific structural formula is shown in formula IrSn3; when the C,N ligand is 2-(naphthyl-2-yl)quinoline, the specific structural formula is shown in formula IrSn4; and when the C,N ligand is 3-(6-phenanthrolidyl)-N,N-diphenylaniline, the specific structural formula is shown in formula IrSn5. 。 8. A method for preparing the tributyltin-cycloiridium imidazoline complex according to claim 6 or 7, characterized in that, Includes the following steps: The cycloiridium imidazophenanthroline benzoic acid complex shown in formula (III) reacts with hexabutyltin oxide to yield the target compound shown in formula (I). The specific reaction route is as follows: 。 9. The application of the tributyltin-cycloiridium imidazoline complex prepared by the method of claim 8 in the field of preparing anticancer drugs.

Images