Chiral optical material based on expanded porphyrin and preparation method thereof

Abstract

The invention relates to the technical field of organic synthesis and chiral optics, and discloses a chiral optical material based on expanded porphyrin and a preparation method of the chiral optical material. The chiral optical material based on expanded porphyrin has a general formula I or a configurational isomer of the general formula I, wherein n is 1 or 2, M is Ni, Pd or Pt, and Mes is 2, 4, 6-trimethylphenyl, and is shown in the description. According to the chiral optical material based on expanded porphyrin, expanded porphyrin containing a plurality of aromatic rings on a conjugate loop is taken as a core, and the expanded porphyrin has stable chirality and chiral optical response of a near-infrared second region due to extension of a pi system and a synergistic effect among a plurality of spiral chiral centers.

Description

Technical Field

[0001] This invention relates to the fields of organic synthesis and chiral optics, and particularly to a chiral optical material based on extended porphyrin and its preparation method. Background Technology

[0002] Near-infrared (NIR) chiral optical materials have become a research focus in cutting-edge interdisciplinary fields such as nanoscience, biomedicine, and photonics due to their unique optical properties. These materials combine the advantages of near-infrared optical windows (such as good penetration depth into biological tissues and low scattering and autofluorescence background) with chiral optical properties (i.e., differentiated responses to left-handed and right-handed circularly polarized light), showing great application potential in multiple dimensions such as deep biological imaging, enantioselective sensing, 3D display, optical information encryption, and spin optoelectronic devices.

[0003] Extended porphyrins are a class of derivatives obtained by structurally extending the classic porphyrin macrocycle, possessing a larger π-conjugated system than the natural tetrapyrrole structure. This extended conjugated structure has not only attracted significant attention in fundamental research areas such as aromaticity theory and metal coordination chemistry, but also endowed them with significant application value in fields such as photodynamic therapy, molecular imaging, optoelectronic devices, and nonlinear optics. Through rational molecular design, such as introducing extended conjugated units or adjusting the ring system size, their photophysical properties can be effectively modulated, extending the optical response range to the near-infrared band.

[0004] However, current research on chiral optical materials mainly focuses on the ultraviolet-visible light band. Although extended porphyrins have shown potential in regulating near-infrared absorption and emission, systematic research and material development regarding their chiral optical properties in the first near-infrared window (NIR-I, 700-900 nm) and the second near-infrared window (NIR-II, 900-1700 nm) remain significantly insufficient. Existing reports on the chiral optical activity of extended porphyrins are mostly limited to the ultraviolet-visible spectral region, lacking effective strategies to simultaneously achieve strong near-infrared II optical response and significant chiral optical activity in these materials. This technological gap severely limits the application expansion of extended porphyrin materials in near-infrared chiral photonics and related high-end technology fields.

[0005] Therefore, there is an urgent need to develop a new material system that can effectively solve the problem of the scarcity of chiral optical materials in the near-infrared region (especially the NIR-II window) in existing technologies, and achieve high-intensity, tunable near-infrared chiral optical response to meet the urgent demand of cutting-edge technology fields for high-performance chiral optical materials. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a chiral optical material based on extended porphyrin and a method for preparing the same, with the aim of providing a chiral optical material based on extended porphyrin.

[0007] The technical solution of the present invention is as follows: A first aspect of the present invention provides a chiral optical material based on extended porphyrin, said chiral optical material having the following general formula I, or a configurational isomer of general formula I: ; Where n is 1 or 2, M is Ni, Pd or Pt, and Mes is 2,4,6-trimethylphenyl. for , , , , , or .

[0008] Optionally, the chiral optical material based on extended porphyrin comprises compounds with the following structural formulas: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , .

[0009] A second aspect of the present invention provides a method for preparing the above-described chiral optical material based on extended porphyrin, the method comprising the following steps: S1: Compound 1 and pyrrole are dissolved in an organic solvent, an acid catalyst is added, and then a first oxidant is added to obtain intermediate 1; S2: Dissolve the intermediate 1 in an organic solvent, add a metal salt, and obtain intermediate 2; S3: Dissolve the intermediate 2 in an organic solvent, add a second oxidant, and then perform chiral resolution on the obtained product to obtain intermediate M-3 and intermediate P-3; S4: Dissolve the intermediate M-3 or intermediate P-3 in an organic solvent, add a catalyst, and after the reaction, obtain the chiral optical material based on extended porphyrin; The structural formulas of compound 1, intermediate 1, intermediate 2, intermediate M-3, and intermediate P-3 are as follows: , , , , .

[0010] Optionally, in step S1, the molar ratio of compound 1 to pyrrole is 1:(18-22).

[0011] Optionally, in step S1, the molar ratio of compound 1 to the acid catalyst is 1:(0.8-1.2).

[0012] Optionally, in step S1, the acid catalyst includes one or more of boron trifluoride ethyl ether, trifluoroacetic acid, methanesulfonic acid, and p-toluenesulfonic acid, preferably boron trifluoride ethyl ether.

[0013] Optionally, in step S1, the first oxidant includes one or more of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetrachloro-p-benzoquinone, ferric chloride (III), and sodium dichromate, preferably DDQ.

[0014] Optionally, in step S2, the molar ratio of intermediate 1 to metal salt is 1:(0.8-1.2).

[0015] Optionally, in step S2, the metal salt includes one of nickel acetate tetrahydrate, palladium acetate, and platinum dichloride.

[0016] Optionally, in step S3, the molar ratio of intermediate 2 to the second oxidant is 1:(1.2-1.8).

[0017] Optionally, in step S3, the second oxidant includes one or more of DDQ, tetrachloro-p-benzoquinone, ferric chloride (III), and sodium dichromate, preferably DDQ.

[0018] Optionally, in step S3, the obtained product is separated using chiral high-performance liquid chromatography.

[0019] Optionally, in step S4, the catalyst includes one or more of the following: bis(1,5-cyclooctadiene)nickel (Ni(COD)2) and 2,2'-bipyridine system, Ni(COD)2 and 4,4'-di-tert-butyl-2,2'-bipyridine system, Ni(COD)2 and pyridine system, preferably Ni(COD)2 and pyridine system.

[0020] Optionally, in step S4, the reaction time after adding the catalyst is 48-60 h, and then the chiral optical material based on extended porphyrin is obtained by gel permeation chromatography purification and separation.

[0021] The present invention has the following beneficial effects: This invention proposes a chiral optical material based on extended porphyrin and its preparation method. Compared with existing technologies, this invention has the following obvious core innovations: 1. Key material innovation: Chiral optical material based on extended porphyrin. This invention creatively uses extended porphyrin as the core chromophore. Compared with standard porphyrin, extended porphyrin has a larger conjugated circuit, and the extension of the π system and the synergistic effect between multiple helical chiral centers give extended porphyrin stable chirality and chiral optical response in the near-infrared II region. 2. Key performance innovation: Achieving high chiral optical response in the near-infrared II region. The most prominent performance breakthrough of this invention is that the prepared material exhibits an absorption asymmetry factor in the near-infrared II region that is significantly higher than that of existing technologies, reaching approximately 0.07. The absorption asymmetry factor is an important parameter for measuring the chiral optical intensity of a material; the larger the value, the greater the difference in absorption between left-handed and right-handed circularly polarized light, and the stronger the chiral response. 3. Key structure-performance relationship innovation: The absorption asymmetry factor of the tetramer is significantly improved compared to that of the trimer. The tetramer structure of this invention exhibits a significantly enhanced chiral optical response. Experiments show that its absorption asymmetry factor reaches 0.069, compared to a structurally similar trimer ( g abs =0.046), an improvement of about 50%. Attached Figure Description

[0022] Figure 1 The images show the chiral high-performance liquid chromatography (HPLC) separations of precursor compounds 1-4 in the preparation examples of this invention.

[0023] Figure 2This is a schematic diagram of the single crystal structure of the chiral optical material compound M-3Ni-IV based on extended porphyrin obtained in Example 1 of the present invention.

[0024] Figure 3 The circular dichroism chromatograms and absorption asymmetry factors of the chiral optical material compounds M-3Ni-IV and P-3Ni-IV based on extended porphyrin prepared in Examples 1 and 2 of this invention are shown.

[0025] Figure 4 The circular dichroism chromatograms and absorption asymmetry factors of the chiral optical material compounds M-4Ni-IV and P-4Ni-IV based on extended porphyrin obtained in Examples 3 and 4 of this invention are shown. Detailed Implementation

[0026] This invention relates to a chiral optical material based on extended porphyrin and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0028] This invention provides a chiral optical material based on extended porphyrin, wherein the chiral optical material based on extended porphyrin has the following general formula I, or is a configurational isomer of general formula I: ; Where n is 1 or 2, M is Ni, Pd or Pt, and Mes is 2,4,6-trimethylphenyl. for , , , , , or .

[0029] The chiral optical material based on extended porphyrin provided in this invention is designed with extended porphyrin as its basic framework. This extended porphyrin is characterized by multiple aromatic rings connected to its conjugated circuit, thus achieving a significant extension of the π-electron system. This extended conjugated structure not only broadens the absorption spectral range of the material, enabling it to cover the near-infrared region, but more importantly, it provides a broad electronic basis for the generation and regulation of chiral optical properties.

[0030] The chirality of a material originates from the introduction of multiple helical chiral centers (as shown in Formula I). ​​These chiral centers do not exist in isolation, but rather generate strong electronic coupling and spatial interactions through an extended π-conjugated system, forming a synergistic effect. This synergistic effect allows the chiral configuration of the entire molecular system to be stably maintained, and enables the effective transfer and amplification of chiral characteristics throughout the large π-conjugated system, thereby inducing a strong intrinsic chiral optical response originating from electronic transitions. The ultimate result is that the chiral optical activity of the material (such as circular dichroism) is effectively advanced and stably exists in the near-infrared II region (NIR-II, typically referring to the 900-1700 nm wavelength range).

[0031] Based on the above technical principles, the material of this invention achieves the following outstanding technical effects: 1. Excellent chiral optical response: The material exhibits significant and stable chiral optical activity in the near-infrared II region. 2. Response wavelength range extending deep into the near-infrared II region: Its characteristic wavelength of chiral optical response can be extended to 1050 nm, successfully achieving effective coverage of the near-infrared II window, laying the material foundation for chiral optical applications in spectral windows with deeper tissue penetration and weaker autofluorescence. 3. High chiral optical intensity: The material's absorption asymmetry factor ( g abs The maximum value can reach 0.069. This value is among the leading levels of near-infrared II chiral materials, indicating that it has the ability to efficiently absorb chiral light and distinguish between left- and right-handed circularly polarized light, which helps to improve the sensitivity and signal-to-noise ratio of related optical devices or biological imaging.

[0032] In summary, by combining the extended porphyrin π-conjugated system with multiple synergistic helical chiral centers, the embodiments of the present invention have successfully created a new type of chiral optical material that possesses both strong chiral optical activity and long wavelength response in the near-infrared II region.

[0033] In some embodiments, the extended porphyrin-based chiral optical material comprises compounds with the following structural formulas: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , .

[0034] This invention provides a method for preparing the above-described chiral optical material based on extended porphyrin, the method comprising the following steps: S1: Compound 1 and pyrrole are dissolved in an organic solvent, an acid catalyst is added, and then a first oxidant is added to obtain intermediate 1; S2: Dissolve the intermediate 1 in an organic solvent, add a metal salt, and obtain intermediate 2; S3: Dissolve the intermediate 2 in an organic solvent, add a second oxidant, and then perform chiral resolution on the obtained product to obtain intermediate M-3 and intermediate P-3; S4: Dissolve the intermediate M-3 or intermediate P-3 in an organic solvent, add a catalyst, and after the reaction, obtain the chiral optical material based on extended porphyrin; The structural formulas of compound 1, intermediate 1, intermediate 2, intermediate M-3, and intermediate P-3 are as follows: , , , , .

[0035] The present invention provides a method for preparing chiral optical materials based on extended porphyrins. The method includes the following steps S1 to S4.

[0036] S1: Synthesis of Intermediate 1 (acid-catalyzed condensation and oxidative aromatization) Compound 1 and pyrrole were dissolved in a suitable organic solvent (e.g., dichloromethane or chloroform). An acid catalyst (e.g., boron trifluoride diethyl ether) was added with stirring. Subsequently, a first oxidant (e.g., 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)) was added to carry out an oxidative aromatization reaction. After the reaction was completed, the product was post-treated (e.g., quenching, extraction, washing, drying, concentration) and purified (e.g., column chromatography) to obtain intermediate 1.

[0037] This step is crucial for constructing the extended porphyrin precursor. Under acid catalysis, compound 1 undergoes a condensation reaction with pyrrole to form an unsaturated intermediate; subsequently, under the action of the first oxidant, it undergoes oxidative aromatization to generate aromatic intermediate 1 with an extended conjugated structure, laying the foundation for its subsequent metal coordination and dimerization.

[0038] S2: Synthesis of intermediate 2 (metal coordination to construct a dimer) Intermediate 1 is dissolved in an organic solvent (e.g., tetrahydrofuran or a mixture of methanol and chloroform). A metal salt (a salt of M, where M is selected from Ni, Pd, or Pt, for example, the corresponding acetate or chloride) is added. The reaction is stirred at a suitable temperature (e.g., room temperature to 80°C). After the reaction is complete, post-processing and purification are performed to obtain metal-coordinated dimer intermediate 2.

[0039] This step introduces the metal ion and constructs the dimer structure. The coordinating atom (such as the nitrogen atom) in intermediate 1 coordinates with the metal ion (M), while the two intermediate 1 units form a stable rigid dimer structure (intermediate 2) through bridging at the metal center or intermolecular interactions. This step not only stabilizes the molecular framework but also predetermines the spatial orientation for subsequent oxidative coupling reactions.

[0040] S3: Synthesis of intermediates P-3 and M-3 (oxidative coupling and chiral resolution) Intermediate 2 is dissolved in an organic solvent (e.g., toluene or benzene). A second oxidant (e.g., DDQ) is added to initiate an oxidative coupling reaction. The reaction product is a pair of racemic chiral isomers. The racemic mixture is separated using chiral separation techniques (preferably chiral high-performance liquid chromatography (HPLC)). The first and last eluents are collected separately, concentrated, and dried to obtain a single-chiral intermediate P-3 (with a p-helix configuration) and intermediate M-3 (with an m-helix configuration).

[0041] This step is crucial for introducing and isolating the chiral center. Under the action of a second oxidant (such as DDQ), intermediate 2 undergoes intramolecular or intermolecular oxidative coupling reactions, forming a helical structure on the extended π system, thereby generating stable helical chirality. Since equal amounts of p-type and M-type enantiomers are generated, precise separation by chiral HPLC is required to obtain optically pure single chiral precursors (P-3 and M-3), providing a chiral source for the final synthesis of optically active target materials.

[0042] S4: Synthesis of target chiral optical materials (coupling into rings) A single chiral intermediate (e.g., intermediate M-3 or intermediate P-3) is dissolved in an organic solvent (e.g., N,N-dimethylformamide (DMF), tetrahydrofuran, or toluene). A catalyst is added. The reaction is carried out under heating conditions (e.g., 50-100°C). After the reaction is complete, the product is purified by separation and purification means (preferably gel permeation chromatography (GPC)) to finally obtain the chiral optical material based on extended porphyrin (having the general formula I structure).

[0043] This step is the final assembly to complete the ring closure of the target molecule. Under the catalysis of a transition metal catalyst, the monochiral intermediate (M-3 or P-3) undergoes an intermolecular coupling cyclization reaction to form the final macrocyclic extended porphyrin skeleton. This ring-closure reaction fixes and inherits the helical chirality of the precursor intermediate, thus yielding the target product with stable, highly chiral optical activity. Purification using GPC can effectively separate the target macromolecular product from the catalyst, small molecule byproducts, and any possible linear oligomers.

[0044] The preparation method provided in this invention achieves controllable preparation of complex chiral extended porphyrin materials from simple raw materials through a multi-step tandem strategy of "condensation aromatization—metal coordination dimerization—oxidative coupling / chiral resolution—catalytic cyclization". This method has a clear route; the key steps combine oxidative coupling with chiral chromatographic resolution to efficiently and reliably introduce stable helical chiral centers, and finally lock the chiral structure through a catalytic cyclization reaction, successfully synthesizing the target material with strong chiral optical response in the near-infrared II region.

[0045] Taking compound 3Ni-IV as an example, the synthesis process is as follows: .

[0046] In some embodiments, in step S1, the molar ratio of compound 1 to pyrrole is 1:(18-22). For example, 1:18, 1:20, or 1:22.

[0047] This specific molar ratio range is a key process parameter for achieving high yield and high selectivity in the synthesis of intermediate 1. Its principles and benefits are as follows: 1. Kinetic drive and equilibrium shift: This condensation reaction is a reversible process. Using a significant excess of pyrrole (18-22 equivalents) as a reactant can significantly shift the chemical equilibrium towards the formation of the condensation product, conforming to Le Chatelier's principle, thus thermodynamically ensuring the reaction is as complete as possible, which is beneficial for improving the theoretical yield of intermediate 1. 2. Suppression of side reactions and improved selectivity: Compound 1 contains multiple reaction sites. The excess pyrrole provides a high-concentration reaction environment, enabling preferential and rapid condensation with the active sites of compound 1, effectively suppressing possible dimerization, oligomerization, or other side reaction pathways of compound 1 itself. This reduces the complexity of the reaction system, significantly improves the selectivity of the reaction, makes the product more singular, and facilitates subsequent purification. 3. Optimization of reaction process and product quality: This molar ratio range is the result of extensive experimental optimization by the inventors. Within this range, the reaction rate is moderate and the exothermic reaction is controllable, enabling the stable generation of the target intermediate and facilitating the subsequent in-situ oxidative aromatization step. The intermediate 1 prepared in this way has higher purity and a well-defined structure, providing a reliable precursor for the subsequent metal coordination step, which is an important foundation for ensuring the reproducibility of the final chiral optical material performance.

[0048] In summary, the molar ratio of compound 1 to pyrrole 1:(18-22) is an optimized choice that integrates thermodynamic impetus, kinetic control, and side reaction suppression, and is the key to achieving the efficient and highly selective first step of the preparation method of this invention.

[0049] In some embodiments, in step S1, the molar ratio of compound 1 to the acid catalyst is 1:(0.8-1.2). For example, 1:0.8, 1:1.0, or 1:1.2.

[0050] Controlling the molar ratio of acid catalyst to compound 1 within this narrow, near-equivalent range is another key process parameter for achieving efficient, controllable, and highly selective conversion in step S1. Its principles and advantages are mainly reflected in: 1. Providing optimal catalytic activity and reaction rate: This condensation reaction relies on acid catalytic activation of reactants (such as the methylene group in compound 1). When the amount of acid catalyst is between 0.8 and 1.2 equivalents, a sufficient but not excessive acidic environment is provided, ensuring efficient and complete activation of the reactants, thereby allowing the condensation reaction to proceed at an ideal rate. This ratio avoids difficulties in reaction initiation or slow progress due to insufficient acid, and also prevents localized over-reactions or side reactions that may be caused by excessive acid. 2. Precisely controlling the reaction process and suppressing side reaction pathways: Compound 1 and intermediates may be sensitive to strong acids or prolonged acidic conditions. Controlling the acid dosage within this precise range allows for precise regulation of the reaction initiation and progress. This helps ensure a smooth reaction and effectively suppresses side reactions that may occur under excessively acidic conditions, such as pyrrole polymerization, excessive protonation of the product, ring opening, or skeletal rearrangement, thereby ensuring the chemical integrity and structural purity of the target intermediate 1. 3. Ensuring intermediate stability and compatibility with subsequent steps: After the reaction, residual acid catalyst in the system needs to be neutralized or removed. Using an amount of acid close to stoichiometry means that the post-processing is simpler, and the salt load in the neutralized system is lower, which is beneficial to improving the separation and purification yield and purity of intermediate 1. At the same time, this also helps to avoid the potential adverse effects of excessive acid on the stability of intermediate 1 (such as causing decomposition) or on the subsequent metal coordination step (S2) (such as competing for coordination with metal salts or causing ligand protonation). 4. Optimizing process economy and environmental friendliness: Using a catalyst close to the theoretical amount meets the requirements of "atom economy" and waste reduction in green chemistry. While ensuring high reaction efficiency, it minimizes the amount of catalyst used and subsequent processing costs, improving the overall economic efficiency and environmental friendliness of the process.

[0051] In summary, limiting the molar ratio of compound 1 to the acid catalyst to 1:(0.8-1.2) is a comprehensive consideration of precise catalytic control, maximizing the selectivity of the main reaction, ensuring product stability, and optimizing process economy. This ratio is an important process condition to ensure that step S1 can stably and reliably prepare high-quality intermediate 1, thereby laying a solid foundation for the success of the entire synthetic route.

[0052] In some embodiments, in step S1, the acid catalyst includes one or more of boron trifluoride ethyl ether, trifluoroacetic acid, methanesulfonic acid, and p-toluenesulfonic acid, preferably boron trifluoride ethyl ether.

[0053] In some embodiments, in step S1, the first oxidant includes one or more of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetrachloro-p-benzoquinone, ferric chloride (III), and sodium dichromate, preferably DDQ.

[0054] In some embodiments, in step S2, the molar ratio of intermediate 1 to the metal salt is 1:(0.8-1.2). For example, 1:0.8, 1:1.0, or 1:1.2.

[0055] Controlling the molar ratio of intermediate 1 to the metal salt within a near-equivalent range of 1:(0.8-1.2) is the core process parameter for achieving high conversion and high-selectivity coordination to construct the key dimer intermediate 2. Its design and advantages are based on the following principles: 1. Compliance with coordination stoichiometry, driving complete reaction: Intermediate 1, as a multidentate organic ligand, forms coordination bonds with the metal ion (M) to constitute the dimer intermediate 2, exhibiting a clear stoichiometric relationship (typically 2 ligand molecules corresponding to 1 metal center). Controlling the amount of metal salt added between 0.8 and 1.2 equivalents (relative to intermediate 1) ensures, stoichiometrically, that the reactant ratio is close to the theoretical optimum. This allows intermediate 1 to be fully and effectively utilized, while also ensuring that the metal ion participates in coordination to the maximum extent, thereby powerfully driving the coordination equilibrium towards the formation of the target dimer 2, achieving high conversion. 2. Ensure coordination integrity and suppress byproduct formation: Insufficient metal salt (<0.8 equivalents) may prevent some intermediate 1 from completing metal coordination, potentially leaving uncoordinated ligands or forming oligomers with a lower degree of polymerization than the target, significantly reducing the purity and yield of the target dimer 2. Excessive metal salt (>1.2 equivalents) may cause multiple problems. First, it may lead to the formation of inactive polynuclear metal complexes or other stoichiometric byproducts. Second, excessive metal salt (especially some oxidizing or coordination-competitive salts) may cause oxidative degradation of ligands or disrupt the coordination environment around the metal center, destroying the regularity of the target dimer structure. Furthermore, residual excess metal ions can become a source of impurities in subsequent steps (such as oxidative coupling S3), potentially catalyzing unnecessary side reactions or affecting chiral resolution efficiency. 3. Optimize product purity and compatibility with subsequent processes: Using this precise ratio minimizes the residue of unreacted raw materials and metal impurities from the source. This makes post-reaction processing (such as washing to remove inorganic salts) more efficient and facilitates the acquisition of high-purity intermediate 2. High-purity intermediate 2 is crucial for the subsequent oxidative coupling reaction (S3) because it ensures a well-defined starting material and a single reaction pathway, thus laying a solid foundation for generating a helical chiral intermediate (P-3 / M-3) with a well-defined structure and high optical purity, ultimately guaranteeing excellent reproducibility of the target chiral optical material's performance. 4. Demonstrating atom economy and process controllability: Controlling the amount of metal salt within a narrow range close to stoichiometry aligns with the pursuit of high atom economy in green synthesis, reducing the waste of precious metals and the heavy metal load in subsequent waste liquids. Simultaneously, this parameter is easy to precisely control and scale up, improving the robustness and reproducibility of the entire preparation process.

[0056] In summary, limiting the molar ratio of intermediate 1 to the metal salt to 1:(0.8-1.2) is an optimization result based on the fundamental principles of coordination chemistry, taking into account factors such as reaction efficiency, product purity, side reaction suppression, and integration with downstream processes. This condition is crucial for the successful construction of a structurally regular, metal-center-coordinated saturated dimer intermediate 2, thus facilitating the subsequent chiral introduction and cyclization steps.

[0057] In some embodiments, in step S2, the metal salt includes one of nickel acetate tetrahydrate, palladium acetate, and platinum dichloride.

[0058] In some embodiments, in step S3, the molar ratio of intermediate 2 to the second oxidant is 1:(1.2-1.8). For example, 1:1.2, 1:1.5, or 1:1.8.

[0059] Controlling the molar ratio of intermediate 2 to the second oxidant within this specific range is a key process parameter for achieving efficient and highly selective oxidative coupling to construct a stable helical chiral framework. Its design principles and significant advantages are as follows: 1. Ensuring complete oxidative coupling reaction and driving helical structure formation: The core of this step is to induce intramolecular coupling and cyclization of intermediate 2 through oxidative dehydrogenation, constructing a large π-conjugated framework with helical chirality. This process typically involves the transfer of multiple electrons, requiring a slight excess of oxidant (1.2-1.8 equivalents) to ensure the reaction is driven to completion. This ratio provides sufficient oxidation potential to effectively overcome the energy barrier of the coupling reaction, ensuring that almost all intermediate 2 can be converted into the target helical product, thereby maximizing the yield of the coupling reaction and reducing the interference of unreacted raw materials on subsequent chiral resolution. 2. Precisely controlling the degree of oxidation and suppressing side reactions: If the oxidant is insufficient (<1.2 equivalents), oxidation will be incomplete, leading to some intermediate 2 failing to complete coupling, producing incompletely reacted linear precursors or partially cyclized products. These byproducts not only reduce the yield of the target helical, but their polarity and chirality may also be close to the target material, greatly increasing the difficulty of subsequent chiral resolution and reducing the recovery rate of optically pure products. Excessive oxidant (>1.8 equivalents) can lead to over-oxidation of sensitive target products under strong oxidizing conditions. Under strong oxidizing agents, the large π-conjugated system of extended porphyrins may undergo irreversible side reactions such as skeletal decomposition, non-selective oxidation, or the formation of quinone structures, destroying the carefully constructed helical conjugated system, leading to product complexity, abnormal color, and ultimately impairing the chiral optical properties of the target material in the near-infrared II region. 3. Optimizing reaction selectivity and product stability: The oxidant range of 1.2-1.8 equivalents is an optimized "reaction window." Within this range, the oxidizing power of the oxidant is sufficient to efficiently and specifically drive the specific carbon-carbon bond coupling required to form the helical structure, while avoiding unintended oxidation at other sites. This ensures high selectivity of the reaction pathway, making the product almost uniquely directed towards the desired pair of racemic helices (P-3 and M-3). The resulting helical structure exhibits excellent chemical integrity and high stability, capable of withstanding subsequent chromatographic separation and purification operations. 4. Ensuring chiral separation efficiency and final product optical purity: The optimized reaction ratio results in a clearly defined product mixture (primarily racemic mixtures of P-3 and M-3) with few byproducts. This creates ideal loading conditions for chiral high-performance liquid chromatography (HPLC) separation: baseline separation is easily achieved, column loading is high, and the collected fractions have high purity. This is a prerequisite for obtaining a single chiral intermediate (P-3 or M-3) with high optical purity, which is fundamental to ensuring that the final target chiral optical material possesses excellent and reproducible near-infrared II chiral response (such as a high absorption asymmetry factor).

[0060] In summary, limiting the molar ratio of intermediate 2 to the second oxidant to 1:(1.2-1.8) is a precise control based on a deep understanding of the oxidative coupling reaction mechanism and effective prediction of side reaction pathways. This condition achieves an optimal balance between reaction completion, process selectivity, and product stability, and is one of the decisive steps in realizing the efficient transformation from an achiral precursor to a high-optical-purity helical chiral intermediate.

[0061] In some embodiments, in step S3, the second oxidant includes one or more of DDQ, tetrachloro-p-benzoquinone, ferric chloride (III), and sodium dichromate, preferably DDQ.

[0062] In some embodiments, in step S3, the obtained product is separated using chiral high-performance liquid chromatography.

[0063] In some embodiments, in step S4, the catalyst added includes one or more of the following: bis(1,5-cyclooctadiene)nickel (Ni(COD)2) and 2,2'-bipyridine system, Ni(COD)2 and 4,4'-di-tert-butyl-2,2'-bipyridine system, Ni(COD)2 and pyridine system, preferably Ni(COD)2 and pyridine system.

[0064] In some embodiments, in step S4, the reaction time after adding the catalyst is 48-60 h, and then the chiral optical material based on extended porphyrin is obtained by gel permeation chromatography purification and separation.

[0065] The following detailed description uses specific examples.

[0066] Preparation Example The following are methods for preparing the precursor compounds involved in subsequent embodiments, including:

[0067] (1) Synthesis of compounds 1-2: Compound 1-1 (13.01 g, 39.20 mmol) and pyrrole (54.39 mL, 78.39 mmol, 20 eq.) were stirred in anhydrous dichloromethane (200 mL) for 1 hour under an argon atmosphere, followed by the slow addition of BF3·OEt2 (4.84 mL, 39.20 mmol, 1.00 equivalence) and stirring at room temperature for 3 hours. DDQ (9.79 g, 43.13 mmol, 1.10 equivalence) was then added, and the reaction was allowed to proceed for 30 minutes. After the reaction was complete, the reaction mixture was poured into a silica gel column (5 cm × 5 cm × 20 cm) to remove the solid and washed with dichloromethane (300 mL). The solvent was removed under reduced pressure, and the residue was further purified by column chromatography (PE / DCM = 4 / 1) to give a brown solid compound 1-2 (8.61 g, 58%).

[0068] NMR data: 1 H NMR (400 MHz, CDCl3) δ 12.37 (brs, 1H), 7.28 (d, J = 3.9Hz, 2H), 6.95 – 6.91 (m, 3H), 6.76 (d, J = 4.5 Hz, 1H), 6.67 (d, J = 4.5 Hz, 1H), 6.22 (m, 1H), 6.15 (d, J = 3.8 Hz, 1H), 2.36 (s, 3H), 2.11 (s, 6H). 13 CNMR (101 MHz, CDCl3) δ 160.53, 149.30, 139.18, 139.01, 137.60, 136.96,135.52, 133.58, 132.98, 132.86, 128.12, 127.94, 127.47, 126.61, 121.36,120.56, 111.64, 21.27, 20.11. Mass spectrometry data: HRMS (ESI): [M+H] + , calcd. for C 22 H 20 ClN2S 379.1030, found379.1118. (2) Synthesis of compounds 1-3: Compounds 1-2 (3.79 g, 10.00 mmol, 1 eq.) and Ni(OAc)₂·4H₂O (2.49 g, 10.00 mmol, 1 eq.) were dissolved in a mixed solvent of tetrahydrofuran (200 mL), methanol (50 mL), and triethylamine (10 mL), and stirred at room temperature for 8 hours. After the reaction was complete, the solvent was removed under reduced pressure, and the residue was extracted with dichloromethane (60 mL × 3). The organic phase was collected, dried over anhydrous sodium sulfate, and then the solvent was removed under reduced pressure. The resulting solid was washed with methanol to give a dark green solid compound 1-3 (3.86 g, 95%).

[0069] Mass spectrometry data: HRMS (ESI): [M+H] + , calcd. for C 44 H 37 Cl2N4NiS2815.1159, found815.1135. (3) Synthesis of compounds 1-4: Compounds 1-3 (2.44 g, 3.00 mmol, 1.00 eq.) and DDQ (0.82 g, 3.60 mmol, 1.20 eq.) were dissolved in toluene (300 mL) and stirred at 110 °C for 12 hours. After cooling to room temperature, the solution was filtered through a silica gel column (10 cm × 10 cm × 5 cm) and washed with a PE / DCM mixture (600 mL, V / V, 1 / 1). The organic solvent was then removed by rotary evaporation, and the residue was purified by column chromatography (PE / DCM = 6:1) to give a brown solid 1-4 (974.92 mg, 40%).

[0070] NMR data: 1 H NMR (400 MHz, Acetone-d6 / CS2= 1 / 1) δ 7.55 (d, J = 3.4 Hz, 2H), 7.04 (s, 2H), 6.95 (d, J = 3.9 Hz, 2H), 6.86 (s, 2H), 6.39 (d, J = 4.3Hz, 2H), 6.24 (d, J = 4.4 Hz, 2H), 6.21 (d, J = 4.2 Hz, 2H), 5.68 (d, J = 4.4Hz, 2H), 2.75 (s, 6H), 2.38 (s, 6H), 1.85 (s, 6H). 13C NMR (101 MHz, Acetone-d6 / CS2= 1 / 1) δ 162.38, 153.13, 142.74, 141.71, 138.31, 138.16, 137.41,136.99, 136.97, 135.40, 133.16, 132.39, 129.76, 128.66, 128.65, 128.05,127.37, 120.58, 115.76, 21.72, 21.13, 20.42. Mass spectrometry data: HRMS (ESI): [M] + , calcd. for C 44 H 34 Cl2N4NiS2812.0924, found812.0912. Compounds 1-4 were chirally separated using high-performance liquid chromatography (HPLC) equipped with a Daicel Chiralpak IB N-5 chiral column (IBN5CE-XA057). The mobile phase was n-hexane / dichloromethane = 9 / 1, the flow rate was 1.0 mL / min, and the detection wavelength was 550 nm. The enantiomers P-1-4 and M-1-4 were obtained, both with ee values ​​greater than 99%. ee is an abbreviation for "enantiomeric excess," which is an indicator used to measure the relative abundance of a pair of enantiomers in a chiral compound.

[0071] The spectra of compounds 1-4 separated by chiral high-performance liquid chromatography are shown below. Figure 1 As shown.

[0072] Example 1 This embodiment provides a chiral optical material compound M-3Ni-IV based on extended porphyrin, and its synthetic route is as follows:

[0073] The preparation method is as follows: In a glove box, M-1-4 (610 mg, 0.75 mmol, 1.00 eq.), Ni(COD)2 (825.2 mg, 3.00 mmol, 4.00 eq.), anhydrous pyridine (1.45 mL, 18.00 mmol, 24.00 eq.), and anhydrous DMF (60 mL) were added to a 100 mL Schlenk tube. After reacting at 50 °C for 18 hours, the reaction tube was removed from the glove box, ethyl acetate (150 mL) was added, and the mixture was washed with 150 mL of water and 90 mL of saturated brine, and dried over anhydrous sodium sulfate. After evaporating the solvent, the residue was filtered through a silica gel column (5 cm × 5 cm × 15 cm) to remove solids, and eluted with dichloromethane (120 mL). After evaporating the solvent, the residue was purified by cyclic gel permeation chromatography (THF). After evaporating the solvent, the residue was washed with methanol. The final product was M-3Ni-IV (50.2 mg, 22.56 μmol, 9.03%).

[0074] NMR data: 1 H NMR (600 MHz, CDCl3) δ 8.25 (d, J = 3.7 Hz, 1H), 7.17 (d,J = 3.7 Hz, 1H), 7.00 (s, 1H), 6.82 (s, 1H), 6.45 (d, J = 4.3 Hz, 1H), 6.31(d, J = 4.3 Hz, 1H), 6.14 (d, J = 4.4 Hz, 1H), 5.69 (d, J = 4.4 Hz, 1H), 2.71 (s, 3H), 2.32 (s, 3H), 1.82 (s, 3H). 13 C NMR (101 MHz, CDCl3) δ 162.06, 152.26,142.02, 140.79, 138.74, 137.66, 136.91, 136.83, 136.75, 136.44, 135.49,134.00, 132.88, 127.99, 127.90, 127.29, 124.24, 120.22, 114.77, 21.24, 20.63,19.99. Mass spectrometry data: MALDI-TOF-MS: [M+H] + , calcd. for C 132 H 103 N 12Ni3S62225.4798, found 2225.4341. The single-crystal structure of compound M-3Ni-IV obtained in this embodiment is as follows: Figure 2 As shown, single-crystal X-ray diffraction analysis of compound M-3Ni-IV indicates that its crystal belongs to the monoclinic crystal system and the space group is P21 (No. 4).

[0075] Example 2 This embodiment provides a chiral optical material compound P-3Ni-IV based on extended porphyrins, and its synthetic route is as follows:

[0076] The preparation method is as follows: In a glove box, P-1-4 (610 mg, 0.75 mmol, 1.00 eq.), Ni(COD)2 (825.2 mg, 3.00 mmol, 4.00 eq.), anhydrous pyridine (1.45 mL, 18.00 mmol, 24.00 eq.), and anhydrous DMF (60 mL) were added to a 100 mL Schlenk tube. After reacting at 50 °C for 18 hours, the reaction tube was removed from the glove box, ethyl acetate (150 mL) was added, and the mixture was washed with 150 mL of water and 90 mL of saturated brine, and dried over anhydrous sodium sulfate. After evaporating the solvent, the residue was filtered through a silica gel column (5 cm × 5 cm × 15 cm) to remove solids, and eluted with dichloromethane (120 mL). After evaporating the solvent, the residue was purified by circulating gel permeation chromatography (THF). After evaporating the solvent, the residue was washed with methanol. The final product was P-3Ni-IV (50.2 mg, 22.56 μmol, 9.03%).

[0077] NMR data: 1 H NMR (600 MHz, CDCl3) δ 8.25 (d, J = 3.7 Hz, 1H), 7.17 (d,J = 3.7 Hz, 1H), 7.00 (s, 1H), 6.82 (s, 1H), 6.45 (d, J = 4.3 Hz, 1H), 6.31(d, J = 4.3 Hz, 1H), 6.14 (d, J = 4.4 Hz, 1H), 5.69 (d, J = 4.4 Hz, 1H), 2.71 (s, 3H), 2.32 (s, 3H), 1.82 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 162.06, 152.26,142.02, 140.79, 138.74, 137.66, 136.91, 136.83, 136.75, 136.44, 135.49,134.00, 132.88, 127.99, 127.90, 127.29, 124.24, 120.22, 114.77, 21.24, 20.63,19.99. Mass spectrometry data: MALDI-TOF-MS: [M+H] + , calcd. for C 132 H 103 N 12 Ni3S62225.4798, found 2225.4341. Figure 3 Circular dichroism chromatograms and absorption asymmetry factors of chiral optical material compounds M-3Ni-IV and P-3Ni-IV based on extended porphyrins are shown.

[0078] Example 3 This embodiment provides a chiral optical material compound M-4Ni-IV based on extended porphyrin, and its synthetic route is as follows:

[0079] The preparation method is as follows: In a glove box, M-1-4 (610 mg, 0.75 mmol, 1.00 eq.), Ni(COD)2 (825.2 mg, 3.00 mmol, 4.00 eq.), anhydrous pyridine (1.45 mL, 18.00 mmol, 24.00 eq.), and anhydrous DMF (60 mL) were added to a 100 mL Schlenk tube. After reacting at 50 °C for 36 hours, the reaction tube was removed from the glove box, ethyl acetate (150 mL) was added, and the mixture was washed with 150 mL of water and 90 mL of saturated brine, and dried over anhydrous sodium sulfate. After evaporating the solvent, the residue was filtered through a silica gel column (5 cm × 5 cm × 15 cm) to remove solids, and eluted with dichloromethane (120 mL). After evaporating the solvent, the residue was purified by circulating gel permeation chromatography (THF). After evaporating the solvent, the residue was washed with methanol. The final product was M-4Ni-IV (15.3 mg, 5.16 μmol, 2.75%).

[0080] NMR data: 1H NMR (400 MHz, Acetone-d6 / CS2= 1 / 1) δ 8.02 (s, 1H), 7.30(s, 1H), 7.01 (s, 1H), 6.84 (s, 1H), 6.46 (d, J = 4.3 Hz, 1H), 6.24 (d, J =4.3 Hz, 1H), 6.13 (d, J = 4.4 Hz, 1H), 5.71 (d, J = 4.4 Hz, 1H), 2.73 (s, 3H), 2.32 (s, 3H), 1.86 (s, 3H). 13 C NMR (101 MHz, Acetone-d6 / CS2= 1 / 1) δ162.51, 152.95, 142.83, 141.29, 139.00, 138.12, 137.35, 137.04, 136.86,135.33, 133.24, 128.69, 128.59, 127.76, 125.80, 121.02, 115.67, 108.64,21.48, 21.05, 20.27. Mass spectrometry data: MALDI-TOF-MS: [MH] + , calcd. for C 176 H 135 N 16 Ni4S82964.6224, found 2964.3816. Example 4 This embodiment provides a chiral optical material compound P-4Ni-IV based on extended porphyrins, and its synthetic route is as follows:

[0081] The preparation method is as follows: In a glove box, P-1-4 (610 mg, 0.75 mmol, 1.00 eq.), Ni(COD)2 (825.2 mg, 3.00 mmol, 4.00 eq.), anhydrous pyridine (1.45 mL, 18.00 mmol, 24.00 eq.), and anhydrous DMF (60 mL) were added to a 100 mL Schlenk tube. After reacting at 50 °C for 36 hours, the reaction tube was removed from the glove box, ethyl acetate (150 mL) was added, and the mixture was washed with 150 mL of water and 90 mL of saturated brine, and dried over anhydrous sodium sulfate. After evaporating the solvent, the residue was filtered through a silica gel column (5 cm × 5 cm × 15 cm) to remove solids, and eluted with dichloromethane (120 mL). After evaporating the solvent, the residue was purified by circulating gel permeation chromatography (THF). After evaporating the solvent, the residue was washed with methanol. The final product was P-4Ni-IV (15.3 mg, 5.16 μmol, 2.75%).

[0082] NMR data: 1 H NMR (400 MHz, Acetone-d6 / CS2= 1 / 1) δ 8.02 (s, 1H), 7.30(s, 1H), 7.01 (s, 1H), 6.84 (s, 1H), 6.46 (d, J = 4.3 Hz, 1H), 6.24 (d, J =4.3 Hz, 1H), 6.13 (d, J = 4.4 Hz, 1H), 5.71 (d, J = 4.4 Hz, 1H), 2.73 (s, 3H), 2.32 (s, 3H), 1.86 (s, 3H). 13 C NMR (101 MHz, Acetone-d6 / CS2= 1 / 1) δ162.51, 152.95, 142.83, 141.29, 139.00, 138.12, 137.35, 137.04, 136.86,135.33, 133.24, 128.69, 128.59, 127.76, 125.80, 121.02, 115.67, 108.64,21.48, 21.05, 20.27. Mass spectrometry data: MALDI-TOF-MS: [MH] + , calcd. for C 176 H 135 N 16Ni4S82964.6224, found 2964.3816. Figure 4 Circular dichroism chromatograms and absorption asymmetry factors of chiral optical material compounds M-4Ni-IV and P-4Ni-IV based on extended porphyrins are shown.

[0083] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A chiral optical material based on extended porphyrin, characterized in that, The chiral optical material based on extended porphyrin has the following general formula I, or is a configurational isomer of general formula I: ; Where n is 1 or 2, M is Ni, Pd or Pt, and Mes is 2,4,6-trimethylphenyl. for , , , , , or .

2. The chiral optical material based on extended porphyrin according to claim 1, characterized in that, The chiral optical materials based on extended porphyrins include compounds with the following structural formulas: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , .

3. A method for preparing a chiral optical material based on extended porphyrin as described in claim 1, characterized in that, The preparation method includes the following steps: S1: Compound 1 and pyrrole are dissolved in an organic solvent, an acid catalyst is added, and then a first oxidant is added to obtain intermediate 1; S2: Dissolve the intermediate 1 in an organic solvent, add a metal salt, and obtain intermediate 2; S3: Dissolve the intermediate 2 in an organic solvent, add a second oxidant, and then perform chiral resolution on the obtained product to obtain intermediate M-3 and intermediate P-3; S4: Dissolve the intermediate M-3 or intermediate P-3 in an organic solvent, add a catalyst, and after the reaction, obtain the chiral optical material based on extended porphyrin; The structural formulas of compound 1, intermediate 1, intermediate 2, intermediate M-3, and intermediate P-3 are as follows: 、 、 、 、 。 4. The method for preparing chiral optical materials based on extended porphyrin according to claim 3, characterized in that, In step S1, the molar ratio of compound 1 to pyrrole is 1:(18-22); the molar ratio of compound 1 to acid catalyst is 1:(0.8-1.2).

5. The method for preparing chiral optical materials based on extended porphyrins according to claim 3, characterized in that, In step S1, the acid catalyst includes one or more of boron trifluoride diethyl ether, trifluoroacetic acid, methanesulfonic acid, and p-toluenesulfonic acid; the first oxidant includes one or more of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, tetrachlorop-benzoquinone, ferric chloride (III), and sodium dichromate.

6. The method for preparing chiral optical materials based on extended porphyrin according to claim 3, characterized in that, In step S2, the molar ratio of intermediate 1 to metal salt is 1:(0.8-1.2).

7. The method for preparing chiral optical materials based on extended porphyrins according to claim 3, characterized in that, In step S3, the molar ratio of intermediate 2 to the second oxidant is 1:(1.2-1.8); the second oxidant includes one or more of DDQ, tetrachloro-p-benzoquinone, ferric chloride (III), and sodium dichromate; the obtained product is separated by chiral high-performance liquid chromatography.

8. The method for preparing chiral optical materials based on extended porphyrin according to claim 3, characterized in that, In step S4, the catalyst includes one or more of the following: bis(1,5-cyclooctadiene)nickel (Ni(COD)2) and 2,2'-bipyridine system, Ni(COD)2 and 4,4'-di-tert-butyl-2,2'-bipyridine system, and Ni(COD)2 and pyridine system.

9. The method for preparing chiral optical materials based on extended porphyrins according to claim 3, characterized in that, In step S4, the reaction time after adding the catalyst is 48-60 h, and then the chiral optical material based on extended porphyrin is obtained by gel permeation chromatography purification and separation.

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