Iron porphyrin-based lantern-like metal-organic capsules, methods of preparation and biomimetic photocatalytic applications thereof

Abstract

The application discloses an iron porphyrin-based lantern-shaped metal-organic capsule, a preparation method thereof and a biomimetic photocatalytic application thereof, and belongs to the technical field of metal-organic supramolecular chemistry and photocatalysis. Fe )3 2+ , which is self-assembled from three biscalix [metal porphyrin iron (III)] ligands and two trinuclear zirconium-oxygen clusters. The preparation method comprises two steps of ligand synthesis and coordination self-assembly. The application further provides a biomimetic photocatalytic application method based on the capsule, that is, a photosensitizer and an electron donor are pre-photolysis pre-incubated to simulate the pre-enrichment process of a cofactor in enzyme catalysis, high-concentration reduced active species are generated, and then the capsule is added for photocatalytic CO2 reduction, so that super-efficient conversion with an initial conversion frequency of 165 s ‑ ¹, a conversion number of 180,000 and CO selectivity of more than 99.9% is realized, and the kinetics presents zero-order dependence on the concentration of the photosensitizer. In addition, the capsule can also couple CO2 reduction with organic molecule oxidation and cyclization reaction to cooperatively generate benzimidazole or benzothiazole compounds. The application provides a new strategy for efficient biomimetic photocatalyst design and has wide application prospects in the fields of carbon neutralization and photosynthetic fuel.

Description

Technical Field

[0001] This invention relates to the fields of metal-organic supramolecular chemistry, photocatalysis, and energy catalysis, specifically to an iron porphyrin-based lantern-shaped metal-organic capsule and its preparation method, as well as the application of the capsule in biomimetic photocatalytic reduction of carbon dioxide to produce carbon monoxide fuel and synergistic organic conversion. Background Technology

[0002] With increasing global emphasis on sustainable development and carbon neutrality, converting the greenhouse gas carbon dioxide into fuels and high-value-added chemicals has become a promising research direction. Utilizing visible light to drive photocatalytic CO2 reduction, mimicking natural photosynthesis, is one of the key technologies for achieving this goal. Among the many reduction products, carbon monoxide has attracted considerable attention due to its role as a feedstock in important industrial processes such as Fischer-Tropsch synthesis. In recent years, researchers have developed various photocatalytic CO2 reduction systems, achieving significant progress in catalytic activity and product selectivity. In particular, homogeneous photocatalytic systems based on metal complexes, with their well-defined structures, ease of modification, and clear mechanisms, have shown great potential for achieving highly selective CO2-to-CO conversion.

[0003] However, existing photocatalytic CO2 reduction systems still face many challenges in practical applications. Although high conversion numbers have been reported, these high-performance systems typically rely on extremely low catalyst concentrations, and their efficiency is limited by the extremely low concentration and short lifetime of transient active species generated by photosensitization. In typical photocatalytic systems, after the photosensitizer is excited by light, it needs to undergo intermolecular collisions with an electron donor to transfer electrons. This process is limited by the diffusion rate, and the steady-state concentration of the generated active species is extremely low, resulting in low efficiency in subsequent electron transfer to the catalytic center. Overcoming the kinetic bottleneck of the photosensitization process while increasing the catalyst concentration is the core challenge for realizing the industrial application of photocatalytic CO2 reduction technology.

[0004] Natural photosynthesis offers important insights into solving these problems: enzymes, through their precisely constructed three-dimensional cavities, pre-organize and enrich cofactors to form high concentrations of reaction intermediates, effectively overcoming the kinetic limitations of diffusion control. Inspired by this, chemists have attempted to construct various biomimetic cavity structures, such as metal-organic cages (MOCs). However, how to efficiently couple these biomimetic structures with the photosensitization process, especially how to address the problem of low transient species concentrations during photosensitization, remains a challenge. Therefore, developing a new method that can mimic enzyme catalytic kinetics and achieve highly efficient and selective CO2 photoreduction has significant scientific and practical value. Summary of the Invention

[0005] The purpose of this invention is to provide a novel iron porphyrin-based lantern-shaped metal-organic capsule and its simple and efficient preparation method, and further to provide a photocatalytic method combining a "pre-incubation" biomimetic strategy to overcome the problem of slow photosensitization kinetics in existing photocatalytic CO2 reduction systems, achieve ultrafast and highly selective CO2 to CO conversion, and expand its application in organic synthesis.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides an iron porphyrin-based lantern-shaped metal-organic capsule having the general formula (Cp3Zr3)2(L Fe )3 2+ It consists of three dicarboxylated metalloporphyrin iron(III) ligands L Fe It is formed by coordination self-assembly with two trinuclear zirconium oxide clusters Cp3Zr3(μ3-O)(μ2-OH)3, and its structure is shown in formula (I): (I) Preferably, the dicarboxylated metalloporphyrin iron(III) ligand L Fe It is a meso-5,10-bis(4-carboxyphenyl)-15,20-diphenylporphyrin iron(III) complex, the structure of which is shown in formula (II): (II).

[0007] The measured electrospray ionization mass spectrometry value of the lantern-shaped metal-organic capsule was m / z = 1720.49, corresponding to [H1]. 2+ Calculated value: 1720.49; Elemental analysis results: C 52.46%, H 3.58%, N 5.11%, theoretical value (corresponding to H1 + 2Cl) - The composition of (+2C3H7NO) is: C 52.04%, H 3.21%, N 4.88%.

[0008] Secondly, the present invention provides a method for preparing the iron porphyrin-based lantern-shaped metal-organic capsule, comprising the following steps: (1) Starting with benzaldehyde and pyrrole, the dicarboxylated metalloporphyrin iron(III) ligand L was obtained through a condensation reaction, a cyclization reaction with methyl p-formylbenzoate, a hydrolysis reaction, and an iron ion coordination reaction. Fe ; (2) The ligand L Fe The mixture was subjected to a coordination self-assembly reaction with zirconium dichloroethylene in the presence of an organic solvent and trace amounts of water. After the reaction, the mixture was separated and dried to obtain the lantern-shaped metal-organic capsule.

[0009] Preferably, the iron salt used in the iron ion coordination reaction in step (1) is selected from ferrous chloride, ferrous sulfate or ferrous acetate; the hydrolysis reaction is carried out under alkaline conditions at 80-100℃ for 12-24 hours.

[0010] Preferably, the ligand L in step (2) Fe The molar ratio of zirconium dichlorodi ...

[0011] Thirdly, the present invention provides a biomimetic photocatalytic application method for the iron porphyrin-based lantern-shaped metal-organic capsule, used for the photocatalytic reduction of carbon dioxide to prepare carbon monoxide, the method comprising the following biomimetic pre-activation steps: (a) Pre-incubation step: The photosensitizer and electron donor are dissolved in an organic solvent and pre-illuminated under a carbon dioxide atmosphere to generate a high concentration of reduced photosensitizer active species, simulating the cofactor pre-enrichment process in enzyme catalysis. (b) Catalytic reduction step: The lantern-shaped metal-organic capsule is added to the pre-illuminated mixture, and a photocatalytic reduction reaction is carried out under a carbon dioxide atmosphere and continuous light to generate carbon monoxide.

[0012] Preferably, the photosensitizer is tris(2-phenylpyridine)iridium with a concentration of 0.05-0.20 mM; the electron donor is 1,3-dimethyl-2-phenyl-2,3-dihydrobenzimidazole with a concentration of 12.5-150.0 mM; the concentration of the lantern-shaped metal-organic capsule is 0.025-0.40 μM; the pre-phototreatment time is 5-20 minutes; and the photocatalytic reduction reaction is carried out in a continuous flow photoreactor.

[0013] Through the above-described pre-incubation and catalytic process, this invention achieves zero-order kinetic dependence on photosensitizer concentration and obtains catalytic performance that surpasses that of natural enzymes and reported catalysts: the initial conversion frequency (TOF) of the capsule reaches 165 s⁻¹, the number of conversions (TON) after 1 hour of reaction reaches 180,000, the CO selectivity is greater than 99.9%, and the quantum yield (ΦCO) is 5.3%.

[0014] Fourthly, the present invention provides the application of the iron porphyrin-based lantern-shaped metal-organic capsule in synergistic biomimetic photocatalysis, that is, coupling the photocatalytic carbon dioxide reduction reaction with the oxidative cyclization reaction of organic molecules, wherein the capsule simultaneously serves as a catalyst for carbon dioxide reduction and an electron transfer medium for the oxidative cyclization reaction.

[0015] Preferably, the organic molecule is a nitrogen- or sulfur-containing aromatic imine, and the product of the oxidative cyclization reaction is a benzimidazole or benzothiazole compound.

[0016] The beneficial effects of this invention are as follows: (1) Structural innovation: This invention provides a novel and highly stable lantern-shaped iron porphyrin metal-organic capsule. Its unique lantern-shaped structure has an open cavity and a suitable opening size, which can dynamically bind photosensitizer molecules through π-π stacking and electrostatic interaction, providing a platform for efficient intermolecular electron transfer.

[0017] (2) Methodological Innovation: This invention proposes and applies a "pre-incubation" strategy for the first time. Before the photocatalytic reaction, the photosensitizer Ir(ppy)3 and the electron donor BIH are irradiated with light, effectively enriching a high concentration of the active reduced species IrII(ppy)3. This key step overcomes the kinetic limitations caused by the low concentration of transient species in traditional photocatalytic systems and is a prerequisite for realizing subsequent ultrafast catalysis.

[0018] (3) Superior performance: By combining the pre-incubation strategy with the confinement effect of the capsule, the photocatalytic CO2 reduction system of this invention exhibits breakthrough catalytic performance. Its initial TOF (165 s⁻¹) is significantly reduced. -1 Both the reaction time (TON) and the reaction time (1 hour) significantly outperformed most reported CO2 photoreduction systems, even surpassing the catalytic rates of natural enzymes such as formate dehydrogenase and carbon monoxide dehydrogenase, with a CO selectivity exceeding 99.9%. Kinetic studies showed that the system achieved zero-order dependence on photosensitizer concentration, successfully mimicking the saturation kinetics of the enzyme.

[0019] (4) Application expansion: The iron porphyrin cage compound of the present invention can not only catalyze CO2 reduction efficiently, but its unique electron transfer mechanism can also drive the oxidative cyclization reaction of organic molecules at the same time, realizing the coupling of photocatalytic reduction and oxidation, and providing a new idea for high-energy-barrier organic conversion reactions to proceed under mild conditions. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 The dicarboxylated metalloporphyrin ligand L in Example 1 Fe Synthesis and L FeA schematic diagram of the iron porphyrin cage compound H1 formed with a trinuclear zirconium oxide cluster.

[0022] Figure 2 The image shows the UV-Vis absorption spectrum of iron porphyrin cage compound H1 from Example 1.

[0023] Figure 3 The electrochemical cyclic voltammogram is shown for the iron porphyrin cage compound H1 in Example 1.

[0024] Figure 4 The emission quenching diagram of photosensitizer Ir(ppy)3 by iron porphyrin cage compound H1 and electron donor BIH in Example 2 is shown.

[0025] Figure 5 This is a UV-Vis absorption spectrum of the catalytic solution system during the incubation process in Example 3.

[0026] Figure 6 The diagram shows the catalytic performance of the photocatalytic CO2 reduction system in Example 2.

[0027] Figure 7 This is a kinetic analysis diagram of photocatalytic CO2 production in Example 2 using the iron porphyrin cage compound H1.

[0028] Figure 8 This is a diagram showing the substrate range and performance of the iron porphyrin cage compound used in the photocatalytic cyclization reactions of CN, CO, and CS in Example 3. Detailed Implementation

[0029] The following examples are provided to better understand the present invention, but do not limit the invention. Unless otherwise specified, the experimental methods in the following examples are conventional methods. Unless otherwise specified, the experimental materials used in the following examples were purchased from conventional biochemical reagent companies. All quantitative experiments in the following examples were performed in triplicate, and the results were averaged.

[0030] Example 1: Synthesis and preparation of metal-organic capsules with porphyrin as the core The synthesis of lantern-shaped metal-organic capsules based on porphyrins is as follows: Figure 1 As shown, the specific synthesis method is as follows: (1) Synthesis of compound 1 using benzaldehyde and pyrrole as raw materials Under argon protection, concentrated hydrochloric acid (37.0%, 1.0 mL) was diluted with deionized water (112 mL), followed by the addition of distilled pyrrole (5.2 mL, 75.0 mmol) with vigorous stirring until a homogeneous solution was formed. Benzaldehyde (2.6 mL, 25.0 mmol) was slowly added dropwise over 10 minutes, and the reaction mixture was stirred at room temperature for 6 hours. After the reaction was complete, the precipitate was collected by vacuum filtration, washed thoroughly with deionized water (3 × 50 mL), and dried under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 1:1) to give a yellow solid compound 1 (2.87 g, yield 51.7%).

[0031] The proton NMR spectrum data of compound 1 ( 1 H NMR, 400 MHz, CDCl3, ppm): δ 7.86 (s, 2H), 7.35-7.16 (m, 5H), 6.66 (q, J = 2.6 Hz, 2H), 6.14 (q, J = 2.8 Hz, 2H), 6.00-5.76 (m, 2H), 5.44 (s, 1H).

[0032] (2) Compound 2 was synthesized from compound 1 and methyl p-formylbenzoate. Compound 1 (3.0 g, 13.5 mmol) was dissolved in propionic acid (100 mL), and methyl p-formylbenzoate (2.2 g, 13.5 mmol) was added. The reaction mixture was heated to 140 °C and reacted for 2 hours. After the reaction was completed, the mixture was cooled to room temperature, and the solvent was removed by vacuum distillation. The crude product was washed successively with saturated potassium carbonate aqueous solution (3 × 50 mL) and saturated brine (3 × 50 mL). The resulting solid was dissolved in dichloromethane and purified by silica gel column chromatography to give compound 2 (0.53 g, yield 10.7%) as a purple solid.

[0033] The proton NMR spectrum data of compound 2 ( 1 H NMR, 400 MHz, CDCl3, ppm): δ 8.89-8.83 (m, 4H), 8.82-8.76 (m, 4H), 8.44 (d, J = 8.2 Hz, 4H), 8.30 (d, J = 8.2 Hz, 4H), 8.21 (d, J = 7.8 Hz, 4H), 7.76 (q, J= 7.2, 6.3 Hz, 6H), 4.11 (s, 6H), -2.79 (s, 2H). Electrospray mass spectrometry data (ESI-MS): calculated C 48 H 35 N4O4[compound 2 + H] + , m / z = 731.27, measured value: 731.27.

[0034] (3) L was synthesized by hydrolysis using compound 2 as a raw material. H Compound 2 (1.0 g, 1.37 mmol) was dissolved in a mixed solvent of tetrahydrofuran and methanol (50 mL each). A 40% potassium hydroxide aqueous solution (40 mL) was added, and the reaction mixture was stirred at 90 °C for 20 hours. After the reaction was complete, the mixture was cooled to room temperature, the pH was adjusted to 3 with concentrated hydrochloric acid, and deionized water (100 mL) was added. The aqueous layer was separated, extracted with chloroform (3 × 100 mL), the organic phases were combined, and the solvent was removed under reduced pressure to give the purple solid product L. H (Yield 32.3%)

[0035] ligand L H 1H NMR spectroscopy data ( 1 H NMR, 400 MHz, DMSO- d 6 (ppm): δ 13.31 (s, 2H), 8.85 (s, 8H), 8.37 (q, J = 8.2 Hz, 8H), 8.23 ​​(dd, J = 7.3, 1.7 Hz, 4H), 7.84 (q, J = 5.4 Hz, 6H), -2.93 (s, 2H). Electrospray mass spectrometry data (ESI-MS): calculated C 46 H 29 N4O4[L H - H] - , m / z = 701.22, measured value: 701.22.

[0036] (4) With L H L was synthesized using FeCl2·4H2O as a raw material. Fe ligand L H(0.17 g, 0.24 mmol) and FeCl2·4H2O (0.48 g, 2.4 mmol) were dissolved in N,N-dimethylformamide (80 mL). The reaction mixture was heated to 130 °C for 12 hours under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, and the solvent was removed by vacuum distillation. The crude product was washed with 50 °C water until the filtrate was colorless and dried under vacuum. The resulting purple solid was dissolved in methanol, filtered, and the filtrate was concentrated under vacuum to give purple solid L. Fe (0.15 g, yield 78.3%). Electrospray ionization mass spectrometry (ESI-MS) data: calculated value C 46 H 27 ClFeN4O4[LFe - H] - , m / z = 790.11, measured value: 790.11.

[0037] (5) With L Fe Lantern-shaped metal-organic cage-like complex H1 was synthesized from zirconium dichlorodichloro as a raw material. Zirconium dichlorocerocene (Cp₂ZrCl₂, 0.04 mmol, 11.7 mg) was dissolved in water (0.3 mL) and sonicated for 10 minutes. Ligand L was then added to this solution. Fe A mixed solution of N,N-dimethylformamide (2.0 mL) and tetrahydrofuran (1.0 mL) (0.02 mmol, 15.9 mg) was prepared. After sonication for 10 minutes, the reaction mixture was heated at 65 °C for 12 hours. After the reaction was complete, the mixture was cooled to room temperature, and the product was washed with N,N-dimethylformamide to give purple blocky crystals H1. The crystals were washed with diethyl ether and dried at room temperature to give the target product (60.6% yield). Figure 2 The UV-Vis spectrum of H1 in acetonitrile solution was presented, and the results show that the characteristic UV signal of iron porphyrin at 410 nm is still retained after the structure is formed. Therefore, it can be confirmed that after the formation of the supramolecular structure, the iron porphyrin core structure in H1 remains intact, and its coordination environment and electronic state are not destroyed, still exhibiting typical iron porphyrin spectral characteristics.

[0038] Electrospray mass spectrometry data (ESI-MS): Calculated value C 168 H 115 N 12 O 20 Zr6Fe3Cl3[H1] 2+ , m / z = 1720.49, Measured value: 1720.49. Elemental analysis data: Theoretical value (C 174 H 128 N 14 O 22 Zr6Fe3Cl5, corresponding to H1 + 2Cl- + 2C3H7NO): C, 52.04; H, 3.21; N, 4.88. Measured values: C, 52.46; H, 3.58; N, 5.11.

[0039] Electrochemical cyclic voltammogram (CV): such as Figure 3 As shown, the cyclic voltammogram of H1 reveals three pairs of redox peaks at -0.25, -1.05, and -1.65 V (relative to the Ag / AgCl electrode). These peaks correspond to Fe, respectively. III / Fe II Fe II / Fe I and Fe I / Fe 0 The reaction pair indicates that it has potential carbon dioxide reduction activity.

[0040] (6) Determination of the crystal structure of metal-organic cage complex H1 The crystal structure of compound H1 was determined using X-ray single-crystal diffraction. A sample with dimensions of 0.13 × 0.11 × 0.08 mm was selected. 3 Purple bulk crystals were observed, and data were collected using a Bruker D8 Venture CCD diffractometer. CuKα radiation (λ = 1.54178 Å) was used, and the data collection temperature was 193 K. Structural analysis was performed using a direct method, refined using the SHELXTL program.

[0041] Crystallographic data are as follows: Molecular formula C 174 H 128 N 14 O 22 Zr6Fe3Cl5, molecular weight 3659.02, monoclinic crystal system, space group C2 / c Cell parameters a = 37.093(2) Å, b = 29.5954(17) Å, c = 23.5846(13) Å, α = 90°, β =102.725(3)°, γ = 90°, V = 25254(2) ų, Z = 4. The final R-factors for structural analysis are R1 = 0.0597 (I > 2σ(I)) and wR2 = 0.1509 (all data). The crystal structure data have been stored in the Cambridge Crystallography Data Centre, CCDC number 2454987.

[0042] Crystal structure analysis revealed that compound H1 possesses a lantern-like structure, assembled from three iron porphyrin units and two trinuclear zirconium-oxygen clusters via coordination bonds. This cage-like structure has a height of 21.1 Å, an average Fe···Zr distance of 12.0 Å, an Fe···Fe distance of 15.7 Å, and three large rhomboid windows (15.7 × 16.2 Å). 2 This provides an open channel for the binding and exchange of guest molecules.

[0043] Example 2: Pre-incubation process and performance testing of photocatalytic CO2 reduction Catalytic reaction: In a sealed quartz reactor, acetonitrile solution (4.91 mL) containing photosensitizer Ir(ppy)3 (0.10 mM), electron donor BIH (50.0 mM), and proton source trifluoroethanol (TFE, 0.25 M) was added. CO2 gas was introduced for 20 minutes to saturate the solution. Subsequently, the mixture was pre-illuminated with a 420 nm LED light source for 15 minutes (pre-incubation). After pre-incubation, a methanol solution of catalyst H1 (10 μL, 0.05 mM) was added via a microsyringe to bring the final concentration of H1 in the system to 0.10 μM. The photocatalytic reaction was continued under 420 nm LED illumination for 30 minutes. During the reaction, the gas from the top of the reactor was periodically extracted and analyzed by gas chromatography. Figure 4 As shown, H1 and BIH can quench the phosphorescence emission of Ir(ppy)3, which means that H1 and BIH can interact with Ir(ppy)3 through energy transfer, electron transfer or the formation of nonradiative complexes, further confirming the rationality of the system selection. Figure 5 The changes in UV signal during the pre-incubation process of the catalytic system are shown, indicating that Ir(ppy)3 is reduced to active Ir under light irradiation in the presence of BIH. II Species enhance catalytic conversion efficiency by inducing electron transfer through directed light.

[0044] Performance characterization: Under the above conditions, 1630 μL of CO was generated within 30 minutes, with selectivity >99.9%. The TON based on H1 reached 145,520, and the initial TOF (first 10 minutes) was approximately 165 s. -1 As a control, the system without pre-incubation produced only 508 μL of CO within 30 minutes under the same conditions, with a TON of 45,360 and an initial TOF of approximately 40 s. -1 .like Figure 6As shown, the comparison of TON and TOF effects between the pre-incubation and non-pre-incubation systems is presented, directly demonstrating that the pre-incubation system can significantly improve catalytic efficiency. Kinetic studies show that in the pre-incubation system, the initial reaction rate is zero-order dependent on the concentrations of photosensitizer Ir(ppy)3 and electron donor BIH, but first-order dependent on the concentrations of proton source TFE and catalyst H1, as shown in the figure. Figure 7 As shown, it exhibits typical enzyme saturation kinetics characteristics.

[0045] Continuous flow reaction: The above reaction system was scaled up to 80 mL and carried out in a continuous flow photoreactor. By precisely controlling the flow rates of CO2 (0.8 mL / min) and reaction liquid (2.0 mL / min) and integrating a 15-minute pre-incubation step, a TON based on H1 was achieved to 362,000 under 2 hours of light irradiation, further demonstrating the industrial application potential of this method.

[0046] Example 3: Iron porphyrin cage compound H1 catalyzes the oxidative cyclization reaction of CN and CS This embodiment provides a specific method for the oxidative cyclization reaction of CN, CO and CS catalyzed by the iron porphyrin cage compound H1. Figure 8 The oxidation cyclization yields of substrates containing CN and CS bonds under different substituent conditions are shown, indicating that the catalytic system has good substrate compatibility.

[0047] (1) A magnetic stir bar was added to a sealed 15 mL quartz reactor to prepare an acetonitrile solution (5.0 mL) containing a 2-substituted imine derivative (10.0 mM, -OH or -NH2), a photosensitizer tri(2-phenylpyridine)iridium (Ir(ppy)3, 0.10 mM), and a proton source trifluoroethanol (TFE, 0.25 M). The reactor was sealed with a rubber stopper, and carbon dioxide gas was bubbled through the solution for 20 minutes to remove oxygen and saturate the solution with carbon dioxide. Subsequently, the mixture was pre-illuminated with a 420 nm blue LED lamp for 15 minutes. After the pre-illumination, the catalyst iron porphyrin cage compound H1 (1.0 μM) was added through a syringe, and the reaction was continued under 420 nm LED illumination for 2 hours. The reaction temperature was maintained at 25 °C by a circulating water bath. During the reaction, 200 μL of the reaction solution was taken every 20 minutes and 1,3,5-trimethoxybenzene, an internal standard, was added. 1 ¹H NMR analysis was used to monitor the reaction progress and calculate the product yield. E The above reaction was carried out using 2-(benzylideneamino)aniline (1a) as a substrate, and the yield of the product 2-phenyl-1H-benzo[d]imidazole (4a) was 82%.

[0048] Product 1H NMR spectroscopy data ( 1H NMR, 400 MHz, DMSO- d 6 ): δ 12.90 (s, 1H), 8.19 (dt, J =8.3, 1.9 Hz, 2H), 7.67 (d, J = 7.3 Hz, 1H), 7.64-7.42 (m, 4H), 7.21 (q, J = 5.7 Hz, 2H).

[0049] (2) A magnetic stir bar was added to a sealed 15 mL quartz reactor to prepare an acetonitrile solution (5.0 mL) containing 2-aminothiophenol (10.0 mM), benzaldehyde derivative (10.0 mM), photosensitizer Ir(ppy)3 (0.10 mM), and proton source TFE (0.25 M). The reactor was sealed with a rubber stopper, and carbon dioxide gas was bubbled through for 20 minutes to remove oxygen from the solution and saturate the solution with carbon dioxide. Subsequently, the mixture was pre-illuminated with a 420 nm blue LED lamp for 15 minutes. After the pre-illumination, the catalyst iron porphyrin cage compound H1 (1.0 μM) was added through a syringe, and the reaction was continued under 420 nm LED illumination for 2 hours. The reaction temperature was maintained at 25 °C by a circulating water bath. During the reaction, 200 μL of the reaction solution was taken every 20 minutes and 1,3,5-trimethoxybenzene, an internal standard, was added. 1 ¹H NMR analysis was performed to monitor the reaction progress and calculate the product yield. The product was generated in situ from benzaldehyde and 2-aminothiophenol (…). E The above reaction was carried out using 2-(benzylideneamino)benzylthiophenol (2a) as a substrate, and the yield of the product 2-phenylbenzo[d]thiazole (5a) was 99%.

[0050] Product 1H NMR spectroscopy data ( 1 H NMR, 400 MHz, CDCl3): δ 8.15-8.04 (m, 3H), 7.90 (d, J =8.0 Hz, 1H), 7.53-7.45 (m, 4H), 7.38 (td, J = 8.3, 7.2, 1.2 Hz, 1H).

[0051] As can be seen from the above embodiments, the iron porphyrin cage compound H1 proposed in this invention and its application method combined with the "pre-incubation" strategy can significantly improve the efficiency of photocatalytic CO2 reduction, achieve record-breaking performance indicators, and can be extended to synergistic organic conversion reactions, demonstrating great scientific research value and application potential.

[0052] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lantern-shaped metal-organic capsule with iron porphyrinyl group, characterized in that, The general formula of the capsule is (Cp3Zr3)2(L Fe )3 2+ It consists of three dicarboxylated metalloporphyrin iron(III) ligands L Fe It is formed by coordination self-assembly with two trinuclear zirconium oxide clusters Cp3Zr3(μ3-O)(μ2-OH)3, and its structure is shown in formula (I): （I）。 2. The iron porphyrin-based lantern-shaped metal-organic capsule according to claim 1, characterized in that, The dicarboxylated metalloporphyrin iron(III) ligand L Fe It is a meso-5,10-bis(4-carboxyphenyl)-15,20-diphenylporphyrin iron(III) complex, the structure of which is shown in formula (II): (II)。 3. The iron porphyrin-based lantern-shaped metal-organic capsule according to claim 1 or 2, characterized in that, Its measured value by electrospray mass spectrometry is m / z = 1720.49, corresponding to [H1]. 2+ Calculated value: 1720.49; Elemental analysis results: C 52.46%, H 3.58%, N 5.11%, theoretical value (corresponding to H1 + 2Cl) - The composition of (+ 2C3H7NO) is: C 52.04%, H 3.21%, N 4.88%.

4. A method for preparing the iron porphyrin-based lantern-shaped metal-organic capsule according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Starting with benzaldehyde and pyrrole, the dicarboxylated metalloporphyrin iron(III) ligand L was obtained through a condensation reaction, a cyclization reaction with methyl p-formylbenzoate, a hydrolysis reaction, and an iron ion coordination reaction. Fe ; (2) The ligand L Fe The mixture was subjected to a coordination self-assembly reaction with zirconium dichloroethylene in the presence of an organic solvent and trace amounts of water. After the reaction, the mixture was separated and dried to obtain the lantern-shaped metal-organic capsule.

5. The preparation method according to claim 4, characterized in that, The iron salt used in the iron ion coordination reaction in step (1) is selected from ferrous chloride, ferrous sulfate or ferrous acetate; the hydrolysis reaction is carried out under alkaline conditions at 80-100℃ for 12-24 hours.

6. The preparation method according to claim 4, characterized in that, The ligand L mentioned in step (2) Fe The molar ratio of zirconium dichlorodi ...

7. A biomimetic photocatalytic application method of the iron porphyrin-based lantern-shaped metal-organic capsule according to any one of claims 1-3, characterized in that, This method, used for the photocatalytic reduction of carbon dioxide to produce carbon monoxide, includes the following biomimetic pre-activation step: (a) Pre-incubation step: The photosensitizer and electron donor are dissolved in an organic solvent and pre-illuminated under a carbon dioxide atmosphere to generate a high concentration of reduced photosensitizer active species, simulating the cofactor pre-enrichment process in enzyme catalysis. (b) Catalytic reduction step: The lantern-shaped metal-organic capsule is added to the pre-illuminated mixture, and a photocatalytic reduction reaction is carried out under a carbon dioxide atmosphere and continuous light to generate carbon monoxide.

8. The biomimetic photocatalytic application method according to claim 7, characterized in that, The photosensitizer is tris(2-phenylpyridine)iridium, with a concentration of 0.05-0.20 mM; the electron donor is 1,3-dimethyl-2-phenyl-2,3-dihydrobenzimidazole, with a concentration of 12.5-150.0 mM; the concentration of the lantern-shaped metal-organic capsule is 0.025-0.40 μM; the pre-illumination treatment time is 5-20 minutes; and the photocatalytic reduction reaction is carried out in a continuous flow photoreactor.

9. The application of the iron porphyrin-based lantern-shaped metal-organic capsule according to any one of claims 1-3 in synergistic biomimetic photocatalysis, characterized in that, The photocatalytic carbon dioxide reduction reaction is coupled with the oxidative cyclization reaction of organic molecules, and the capsule simultaneously serves as a catalyst for carbon dioxide reduction and an electron transfer medium for the oxidative cyclization reaction.

10. The application according to claim 9, characterized in that, The organic molecule is a nitrogen- or sulfur-containing aromatic imine, and the product of the oxidative cyclization reaction is a benzimidazole or benzothiazole compound.

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