sp 2 Carbon-bonded porous organic molecular cage materials, and preparation and use thereof

Abstract

A kind of porous organic cage compound (abbreviation is sp 2 c-POC), it has the connection unit structure formed by aromatic polyaldehyde and aromatic polyacetonitrile. Preferably, one porous organic cage compound is assembled by the three-hat three-mitsubishi column structure organic cage of 2 concave aromatic tri-aldehyde ligand as face and 3 m-bisacetonitrile ligand as column, it includes 1 three-hat three-mitsubishi column cavity and 3 windows. The porous organic cage compound of the present application can form porous porous organic cage sp 2 c-POC crystal, the crystal is applied as porous material in gas storage and gas separation. The porous material of the present application has simple preparation process, low cost, simple operation, high yield, high chemical stability of the product prepared, larger specific surface area, good repeatability, very strong operability and practicality.

Description

Technical Field

[0001] This invention belongs to the field of crystalline porous material synthesis, specifically relating to a method for synthesizing crystalline porous materials using sp 2 - Highly stable porous organic molecular cages linked by carbon bonds (sp 2 -POC) materials, their preparation methods and applications. Background Technology

[0002] Porous organic cages (POCs) are a new type of porous material that has emerged in recent years. They contain cavities of specific sizes and are formed by the stacking of discrete building blocks through weak interactions into an ordered structure. Their pores consist of internal cavities and interconnected pores, showing potential applications in gas storage and separation, sensing, catalysis, and smart materials. However, to date, most POCs are composed of reversible imine (C=N) or borate (BO) bonds. Due to the reversible nature of these chemical bonds, most POC materials are prone to hydrolysis, leading to structural collapse and severely limiting their application in practical production and daily life. Although chemists have recently developed methods to address the poor stability of POCs, such as using irreversible covalent bonds (CC and acetylene bonds) and modifying imines to more stable amide, urethane, and quinoline bonds, these approaches have been implemented. However, existing methods for constructing stable organic cages are mostly cumbersome, have low yields, and require precious metal catalysts. Therefore, it is essential to develop a simple method for constructing stable organic cages.

[0003] sp 2 Due to its combination of π-conjugation and stable C=C linkage, the π-carbon (C=C) bond has been widely used in recent years to construct covalent organic frameworks (COFs). These materials typically exhibit more unique properties than other bonded conjugated COFs, demonstrating great application potential in areas such as photocatalysis, lithium-ion batteries, and hydrogen-oxygen fuel cells. Unlike COF frameworks, POCs (Polyvalent Organic Frameworks) possess good solubility due to their discrete nature. Therefore, they can be easily processed, regenerated, and functionalized in solution. However, to date, the simple and high-yield synthesis of POCs has been limited. 2 Highly chemically stable POCs linked by carbon bonds have not yet been reported. Summary of the Invention

[0004] This invention provides a method for preparing highly chemically stable sp using an inexpensive inorganic base catalyst via a simple one-step self-assembly. 2 - A method for porous organic cages linked by carbon bonds.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] A porous organic cage compound (abbreviated as sp) 2 c-POC), which has a linking unit structure formed by aromatic polyaldehydes and aromatic polyacetonitrs as shown in Formula I:

[0007]

[0008] According to an embodiment of the present invention, the compound is obtained by reacting aromatic polyaldehydes and aromatic polyacetonitrile ligands.

[0009] According to an embodiment of the present invention, at least one of the ligands is of a concave configuration.

[0010] Preferably, the aromatic polyaldehyde is a concave aromatic trialdehyde, and the aromatic polyacetonitrile is isophthalic acid acetonitrile. As examples, they are shown in Formula II and Formula III respectively:

[0011]

[0012] In Equation II, X is selected from H and C. 1-6 Alkyl groups, for example, X is methyl (Me); ethyl (Et); propyl (Pr); isobutyl (iBu). In Formula III, Y is selected from H, C 1-6 Alkyl, for example, Y is hydrogen, H; methyl, Me; ethyl, Et; propyl, Pr; tert-butyl, tBu.

[0013] In this invention, the concave configuration refers to the situation where the aldehyde and / or cyano groups of the aromatic polyaldehydes and / or aromatic polyacetonitrs participating in the bond chain reaction are all on the same side of the plane of the aromatic ring. For example, the aromatic trialdehydes shown in Formula II above have their three aldehyde groups on the same side of the plane formed by the aromatic ring system, forming a concave three-dimensional structure. The concave configuration of the ligands is beneficial for forming the organic cage molecule of this invention, which can be prepared or purchased by methods known in the prior art, such as the methods of the embodiments of this invention.

[0014] For example, Formula II is isobutyl-aromatic trialdehyde (iBu-C3CHO), and Formula III is 5-methyl-1,3-phenylene diacetonitrile (Me-BDN).

[0015] According to an embodiment of the present invention, the molar ratio of the aromatic polyaldehyde and the aromatic polyacetonitrile ligand in the reaction is 1:(1 to 4), for example 1:1, 1:1.5, or 1:3.

[0016] According to an embodiment of the present invention, the compound is composed of two aromatic polyaldehydes and three aromatic polyacetonitrile bonds. Specifically, the porous organic cage compound is a three-capped triangular prism structure organic cage assembled from two concave aromatic trialdehyde ligands as faces and three isophthalic acetonitrile ligands as pillars. Preferably, it includes a three-capped triangular prism cavity and three windows, and its molecular structure diagram is shown in Formula IV below:

[0017]

[0018] Formula IV sp 2 Schematic diagram of the molecular structure of c-POC

[0019] The present invention also provides an sp 2 c-POC crystals are formed from porous organic cage compounds as described above.

[0020] According to an embodiment of the present invention, the porous organic cage sp 2 The c-POC crystal space group is P21 / c, and the unit cell parameters are... α=γ=90°, β=104.125(3),

[0021] According to an embodiment of the present invention, the porous organic cage sp 2 c-POC crystals are formed by stacking a three-capped triangular prism structure organic cage, as described above, which consists of two concave aromatic trialdehyde ligands as faces and three isophthalic acid ligands as pillars. Preferably, the porous organic cage molecule includes one three-capped triangular prism cavity and three windows.

[0022] According to an embodiment of the present invention, the porous organic cage sp 2 The maximum cavity height and the maximum spherical diameter that a c-POC crystal can accommodate are approximately 1.14 nm and 0.56 nm, respectively.

[0023] According to an embodiment of the present invention, the porous organic cage sp 2 The number of porous organic cage molecules Z in the unit cell of c-POC crystal is 4.

[0024] According to an embodiment of the present invention, the porous organic cage sp 2 The average length of the window in c-POC crystal is approximately 0.80 nm (which allows molecules with a diameter of approximately 0.56 nm to pass through).

[0025] According to an embodiment of the present invention, the porous organic cage molecule has the structure shown in FIG1.

[0026] According to an embodiment of the present invention, the porous organic cage sp 2 c-POC crystals have essentially the following properties: Figure 6The X-ray powder diffraction pattern shown is shown below.

[0027] According to an embodiment of the present invention, the porous organic cage sp 2 The BET surface area of ​​c-POC crystals is 150-600 m². 2 g -1 , example sp 2 c-POC is 325m 2 g -1 .

[0028] This invention also provides the porous organic cage compound (abbreviated as sp). 2 The preparation method of c-POC includes: reacting two ligands under solvothermal conditions in the presence of a catalyst.

[0029] According to embodiments of the present invention, the ligand is as defined above. Exemplarily, the compound is obtained by reacting isobutyl-aromatic trialdehyde (iBu-C3CHO) with 5-methyl-1,3-phenylenediacetonitrile (Me-BDN).

[0030] According to an embodiment of the present invention, the molar ratio of the ligand aromatic polyaldehyde and the aromatic polyacetonitrile is 1:

[0031] (1-4), with examples being 1:1, 1:1.5, and 1:4.

[0032] According to an embodiment of the present invention, the temperature of the reaction is 60-100°C, for example 80°C; and the reaction time is 6-20 hours, for example 12 hours.

[0033] According to an embodiment of the invention, the reaction is carried out in a mixed organic solvent. For example, the mixed solvent may be tetrahydrofuran (THF) and methanol (MeOH).

[0034] According to an embodiment of the present invention, the reaction mechanism between the aromatic polyaldehyde and the aromatic polyacetonitrile is the base-catalyzed Knoevenagel condensation reaction known to those skilled in the art, and the catalyst can be any catalyst known in the prior art, such as inorganic salts, phase transfer catalysts, solid-phase catalysts, etc. In this invention, a base catalyst is used, such as carbonates of alkali metals and alkaline earth metals, such as cesium carbonate (Cs₂CO₃).

[0035] In an embodiment of the present invention, the preparation method further includes evacuating the reaction mixture and providing gas protection before heating the reaction. Preferably, the evacuation time can be 3 to 15 minutes. An example is about 5 minutes. Preferably, the protective gas is nitrogen.

[0036] According to an embodiment of the present invention, the preparation method further includes: after the reaction is completed, collecting sp from the reaction solution. 2 The process of c-POC compound formation.

[0037] The present invention also provides the above-mentioned porous organic cage sp 2 Applications of c-POC crystals as porous materials in gas storage. Preferably, applications in the adsorption of carbon dioxide and low-carbon hydrocarbons (e.g., C1-C6 hydrocarbons).

[0038] According to embodiments of the present invention, the gas includes, but is not limited to, one or more of carbon dioxide, methane, ethane, ethylene, acetylene, and propane.

[0039] The present invention also provides the above-mentioned porous organic cage sp 2 Applications of c-POC crystals as porous materials in gas separation. Preferably, applications in separating carbon dioxide / methane and carbon dioxide / nitrogen mixtures.

[0040] According to an embodiment of the present invention, before performing gas adsorption and separation tests on the sample, it is also necessary to test the sp... 2 Guest molecules in the cavities of c-POC crystals are removed. For example, by filtration, methanol washing, methanol exchange several times, and vacuum drying, a white powder containing the removed guest solvent molecules is obtained. 2 c-POC porous material. (Appendix to this invention) Figure 2 sp 2 c-POC 1H NMR spectroscopy indicates successful removal of the guest molecule. Preferably, the drying temperature can be 60–100°C, exemplarily 100°C; the drying time is 6–20 h, for example 12 h.

[0041] The beneficial effects of this invention:

[0042] sp 2 The π-carbon (C=C) bond, possessing both π-conjugation and stable C=C connectivity, has been widely used in recent years to construct porous organic framework materials. These materials, due to their porosity, high specific surface area, and high stability, exhibit great application potential in catalysis, separation, and batteries. However, the insolubility of these framework materials significantly limits their dissolution and processing, thus necessitating the development of a soluble sp... 2 -Porous materials linked by carbon bonds; therefore, we designed and developed p 2 -Porous organic cages linked by carbon bonds (sp 2 c-POC material. Specifically:

[0043] This invention proposes a one-step, high-yield synthesis method for sp from aromatic polyaldehydes and aromatic polyacetonitrile ligands via a base-catalyzed Knoevenagel condensation reaction. 2 - Highly chemically stable porous organic cages linked by carbon bonds. This method requires inexpensive catalysts, has a simple preparation process, is easy to operate, yields high output, and produces products with high chemical stability, large specific surface area, and good reproducibility. It has strong operability and practicality, with potential applications in gas storage and separation. Therefore, a method for constructing highly stable porous organic cages is essential. Attached Figure Description

[0044] Figure 1a For porous organic cages sp 2 Schematic diagram of c-POC synthesis Figure 1b This is a schematic diagram of the structure.

[0045] Figure 2 For sp 2 c-POC 1H NMR spectrum ( 1 H NMR).

[0046] Figure 3 For sp 2 c-POC after soaking in boiling water, strong acid, and strong alkali... 2 c-POC 1H NMR spectrum

[0047] Figure 4 For sp 2 The infrared spectrum (FT-IR) of c-POC.

[0048] Figure 5 For sp 2 Thermogravimetric analysis (TGA) curve of c-POC.

[0049] Figure 6 For sp 2 Powder X-ray diffraction (PXRD) pattern of c-POC.

[0050] Figure 7 For sp 2 CO2 adsorption-desorption curves of c-POC at 196K.

[0051] Figure 8 For sp 2 Adsorption-desorption curves of c-POC for carbon dioxide at 273 and 293 K.

[0052] Figure 9 For sp 2 methane adsorption-desorption curves of c-POC at 273 and 298 K.

[0053] Figure 10 For sp 2 Ethane adsorption-desorption curves of c-POC at 273 and 298 K.

[0054] Figure 11 For sp 2 Ethylene adsorption-desorption curves of c-POC at 273 and 298 K.

[0055] Figure 12 For sp 2 Adsorption-desorption curves of c-POC at 273 and 298 K for acetylene.

[0056] Figure 13 For sp 2 Adsorption-desorption curves of c-POC for propane at 273 and 298 K.

[0057] Figure 14 For sp 2 Separation curve of c-POC for carbon dioxide / methane mixture at 298K.

[0058] Figure 15 For sp 2 Separation curve of c-POC for carbon dioxide / nitrogen mixture at 298K. Detailed Implementation

[0059] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0060] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0061] Example 1

[0062] sp 2 The preparation method of c-POC includes the following steps:

[0063] (1) Synthesis of iBu-C3CHO ligand:

[0064]

[0065] Anhydrous aluminum trichloride (AlCl3, 19.8 g, 133 mmol, 1.8 eq) was suspended in dichloromethane (CH2Cl2, 25 mL) and heated to 40 °C. 4-Isobutylbenzaldehyde (12.3 mL, 73.8 mmol, 1.0 eq) was added dropwise, and the resulting mixture was further refluxed for 30 min. Liquid bromine (Br2, 4.80 mL, 93.7 mmol, 1.27 eq) was dissolved in CH2Cl2 (25 mL) and added via a dropping funnel for at least 1 h. After refluxing for another 30 min, the reaction mixture was cooled to ambient temperature and poured onto ice (200 mL). CH2Cl2 (30 mL) was added, and the phases were separated. The aqueous layer was extracted twice with CH2Cl2 (50 mL each time), washed twice with brine (100 mL each time), and washed once with saturated Na2S2O3 solution (50 mL). After drying on MgSO4, the desired product 3-bromo-4-isobutylbenzaldehyde was obtained in a yellow oily form at a yield of 13.4 g (56 mmol, 76%). 1 H NMR (400MHz, CDCl3): δ = 9.82 (s, 1H), 7.96 (d, J = 5.2Hz, 1H), 7.65 (d, J = 8.1Hz, J = 1Hz, 1H), 7.25 (d, J = 7.9Hz ,1H), 7.47(d,J=7.6Hz,3H),7.33(s,3H),2.68(d,J=7.8Hz,2H),1.96-2.08(m,1H),0.95(d,J=8.2Hz,6H).

[0066]

[0067] 1,3,5-Tris(4,4,5,5-tetramethyl-1,3,2-dioxaboron-2-yl)benzene (1 g, 2.2 mmol), 3-bromo-4-isobutylbenzaldehyde (2.4 g, 10.0 mmol), and tetrakis(triphenylphosphine)palladium (Pd(PPh3)4, 80 mg) were added to a mixture containing THF (50 mL) and an aqueous solution of K2CO3 (2 M; 15 mL). The mixture was stirred vigorously at 85 °C for 48 hours. After cooling the mixture to room temperature, it was poured into deionized water (150 mL). The aqueous layer was extracted three times with dichloromethane. The combined organic solutions were washed with water and dried over MgSO4. After removing the solvent by evaporation, the crude sample was purified by rapid column chromatography with ethyl acetate / n-pentane (1:1) (EA / PE (1:1)); silica gel, 200-300 mesh, to produce the pure product, isobutyl-aromatic trialdehyde (iBu-C3CHO) (556 mg, 45%), a yellow solid. 1H NMR (400MHz, CDCl3): δ = 10.02 (s, 3H), 7.84 (d, J = 2.1Hz, J = 2.9Hz, 3H), 7.45 (d, J = 8 .1Hz, 3H), 7.28 (s, 3H), 2.68 (d, J = 4Hz, 6H), 1.82 (m, 3H), 0.81 (d, J = 3.85Hz, 18H).

[0068] (2)sp 2 c-POC crystal synthesis: SP was synthesized in a pressure-resistant tube using a conventional solvothermal method. 2 c-POC crystals were prepared by dissolving isobutyl-aromatic trialdehyde (iBu-C3CHO, 10.8 mg, 0.2 mmol) and 5-methyl-1,3-phenyleneacetonitrile (5.1 mg, 0.3 mol) in tetrahydrofuran (2 mL) and adding a methanol solution (0.5 mL) of cesium carbonate (Cs2CO3, 3.26 mg, 0.01 mol). The mixture was frozen in liquid nitrogen, evacuated for 5 min, backfilled with nitrogen, and the process was repeated three times. Colorless crystals were obtained after reacting in an oven at 80 °C for 12 h. The crystals were then filtered, washed with methanol, and vacuum dried to obtain a white powder. 2 c-POC, yield 88%. ¹H NMR (400MHz, CDCl₃): δ=7.90(dJ=2.4Hz, J=7.6Hz, 6H), 7.72(d, J=1.8Hz, 6H), 7.62(d, J=2Hz, 3H), 7.58(d, J=1.9Hz, 6H), 7.33(d, J=8Hz, 6H), 7.18(s, 6H), 2.56(d, J=7.8Hz, 12H), 2.39(s, 9H), 1.72–1.80(m, 6H), 0.74(d, J=8.2Hz, 36H).

[0069] sp 2 c-POC characterization methods:

[0070] (3) Sproutine crystals characterized by single-crystal diffraction (SCXRD) 2 The c-POC structure and the results are shown in Table 1 below.

[0071] Table 1 shows the sp 2 Crystallographic data of c-POC

[0072]

[0073] R1 a =∑||F o |-|F c || / ∑|F o | b wR2={∑[w(Fo 2 -F c 2 ) 2 ] / ∑[w(F o 2 ) 2 ]} 1 / 2

[0074] The single-crystal structures in Table 1 show that:

[0075] sp 2 c-POC crystals in the monoclinic P21 / c space group are composed of organic cages stacked in a tri-capped triangular prism structure, assembled from two isobutyl aromatic trialdehyde (iBu-C3CHO) ligands as vertices and three 5-methyl-1,3-phenylene diacetonitrile (Me-BDN) ligands as edges. It contains one tri-capped triangular prism-shaped cavity and three windows. The maximum cavity height and the maximum diameter of the posable sphere are approximately 1.14 nm and 0.56 nm, respectively. Furthermore, the windows are approximately hexagonal, with an average length of approximately 0.8 nm, allowing passage of molecules with a diameter of approximately 0.56 nm (such as...). Figure 1a (as shown in 1b).

[0076] (4) The dried sp 2 The c-POC sample was subjected to 1H NMR spectroscopy ( 1 Characterization by ¹H NMR, the results are as follows Figure 2 As shown in the figure, the appearance of the characteristic peak of HC=C (7.80ppm) represents sp. 2 Efficient synthesis of c-POC organic cages.

[0077] (5) sp 2 The c-POC sample was immersed in boiling water for one week, and then in concentrated hydrochloric acid, concentrated nitric acid, and saturated sodium hydroxide solutions for 24 hours. After drying, it was subjected to 1H NMR spectroscopy. The results are as follows: Figure 3 As shown, the spectrum remains unchanged from before, verifying the sp... 2 The stability of c-POC in aqueous environment and under strong acid and strong alkali conditions.

[0078] (6) Figure 4 For sp 2 The Fourier Transform Infrared (FT-IR) spectrum of c-POC was obtained, and sp was observed using FT-IR spectroscopy. 2 C≡N (2221cm) in c-POC cage -1 ) and C = C(1591cm) -1 Characteristic infrared vibration signal, indicating sp 2 c-POC exists stably under solid conditions.

[0079] (7) Figure 5 For sp 2 The thermogravimetric analysis (TGA) curve of c-POC shows that, through TGA analysis, sp 2 c-POC can be stabilized up to 420℃.

[0080] (8) Figure 6 For sp 2 The X-ray powder diffraction (PXRD) pattern of c-POC shows many sharp peaks in the 4–40° range, indicating that sp 2 The c-POC sample becomes crystalline after activation.

[0081] (9) Figure 7 For sp 2 The adsorption-desorption curves of carbon dioxide (CO2) from c-POC, as shown by gas adsorption tests at 196 K, indicate that sp... 2 The adsorption capacity of c-POC at one atmosphere (1 atm) is 158 cm⁻¹. 3 g -1 The corresponding surface integral is 325m. 2 g -1 .

[0082] (10) Figure 8 For sp 2 The CO2 adsorption-desorption curve of c-POC indicates that sp 2 The CO2 adsorption capacities of c-POC at 273 K and 298 K under one atmosphere (1 atm) were 37.4 and 27.3 cm⁻¹, respectively. 3 g -1 .

[0083] (11) Figure 9 For sp 2 The methane (CH4) adsorption-desorption curve of c-POC indicates that sp 2 The CH4 adsorption capacities of c-POC at 273 K and 298 K under one atmosphere (1 atm) were 11.3 and 6.0 cm⁻¹, respectively. 3 g -1 .

[0084] (12) Figure 10 For sp 2 The adsorption-desorption curve of ethane (C2H6) from c-POC indicates that sp 2 The C2H6 adsorption capacities of c-POC at 273 K and 298 K under one atmosphere (1 atm) were 34.0 and 24.7 cm⁻¹, respectively. 3 g -1 .

[0085] (13) Figure 11 For sp2 The adsorption-desorption curve of ethylene (C2H4) from c-POC indicates that sp 2 The C2H4 adsorption capacities of c-POC at 273 K and 298 K under one atmosphere (1 atm) were 32.3 and 21.5 cm⁻¹, respectively. 3 g -1 .

[0086] (14) Figure 12 For sp 2 The adsorption-desorption curve of acetylene (C2H2) from c-POC indicates that sp 2 The C2H2 adsorption capacities of c-POC at 273 K and 298 K under one atmosphere (1 atm) were 34.9 and 25.9 cm⁻¹, respectively. 3 g -1 .

[0087] (15) Figure 13 For sp 2 The adsorption-desorption curve of propane (C3H8) from c-POC indicates that sp 2 The C3H8 adsorption capacities of c-POC at 273 K and 298 K under one atmosphere (1 atm) were 28.4 and 16.7 cm⁻¹, respectively. 3 g -1 .

[0088] (16) Figure 14 For sp 2 The separation performance of c-POC for CO2 / CH4 in a packed column compared to sp 2 c-POC was used in a real-world gas breakthrough study of a CO2 / CH4 (50%:50%) mixture at 298 K. The results showed that sp... 2 c-POC solid can achieve complete separation of CO2 / CH4 mixtures with a retention time of approximately 8 min. -1 .

[0089] (17) Figure 15 For sp 2 The separation performance of c-POC for CO2 / N2 in packed columns compared to sp 2 c-POC was used in a real-world gas breakthrough study of a CO2 / N2 (15%:85%) mixture at 298 K. The results showed that... 2 c-POC solid can achieve complete separation of CO2 / N2 mixtures with a retention time of approximately 19 min. -1 .

[0090] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. 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 porous organic cage compound, abbreviated as sp 2 c-POC, which is formed by ligands aromatic polyaldehydes and aromatic polyacetonitrs to form the linking unit structure shown in Formula I: The aromatic polyaldehyde is a concave aromatic trialdehyde, and the aromatic polyacetonitrile is isophthalic acid acetonitrile, as shown in Formula II and Formula III below, respectively: in, X is selected from H, C 1-6 Alkyl group, Y is selected from hydrogen, C 1-6 alkyl; The porous organic cage compound is a three-capped triangular prism structure organic cage assembled from two concave aromatic trialdehyde ligands as faces and three isophthalonitrile ligands as pillars.

2. The porous organic cage compound according to claim 1, wherein the aromatic trialdehyde is selected from compounds in formula II where X is isobutyl, and the isophthalic acid nitrile is selected from compounds in formula III where Y is methyl.

3. The porous organic cage compound according to claim 1, wherein the organic cage comprises a three-capped triangular prism-shaped cavity and three approximately hexagonal windows, and its molecular structure is shown in the following formula IV: 。 4. A porous organic cage sp 2 c-POC crystals, which are formed from the porous organic cage compound according to any one of claims 1-3; The porous organic cage sp 2 c-POC crystal space group is P 21 / c, cell parameters are a=18.3145(7) Å, b=35.8224(12) Å, c=17.3139(5) Å, α=γ=90°, β=104.125(3), V=11015.7(7) Å 3 .

5. The crystal according to claim 4, wherein the porous organic cage sp 2 The maximum cavity height and the maximum spherical diameter that c-POC crystal can accommodate are 1.14 nm and 0.56 nm, respectively; or The porous organic cage sp 2 The number of porous organic cage molecules Z within the unit cell of c-POC crystal is 4; or The porous organic cage sp 2 The average length of the hexagonal window in the c-POC crystal is 0.80 nm; or porous organic cage sp 2 The BET surface area of ​​c-POC crystals is 150-600 m². 2 g -1 .

6. The crystal according to claim 5, wherein the porous organic cage sp 2 c-POC crystals have an X-ray powder diffraction pattern that is essentially as shown in Figure 6.

7. A method for preparing the porous organic cage compound according to any one of claims 1-3, comprising: The two ligands were reacted under solvothermal conditions in the presence of a catalyst.

8. The preparation method according to claim 7, wherein the porous organic cage compound is obtained by reacting an aromatic polyaldehyde in formula II (where X is isobutyl) with an aromatic polyacetonitrile in formula III (where Y is methyl); or The molar ratio of the ligand aromatic polyaldehyde to the aromatic polyacetonitrile is 1:(1~4); or The reaction temperature is 60~100℃; the reaction time is 6-20h; or The reaction is carried out in a mixed organic solvent; or An alkaline catalyst is used.

9. The preparation method according to claim 8, The mixed organic solvent is tetrahydrofuran (THF) and methanol (MeOH); or The alkaline catalyst is a carbonate of an alkali metal or an alkaline earth metal.

10. The porous organic cage sp according to any one of claims 4-6 2 Applications of c-POC crystals as porous materials in gas storage.

11. The application according to claim 10, wherein it is used for the adsorption of carbon dioxide or C1-C6 hydrocarbon gases.

12. The application according to claim 11, wherein the gas is selected from one or more of carbon dioxide, methane, ethane, ethylene, acetylene, and propane.

13. The porous organic cage sp according to any one of claims 4-6 2 Application of c-POC crystals as porous materials in gas separation.

14. The application according to claim 13, which is an application in separating carbon dioxide / methane mixtures or carbon dioxide / nitrogen mixtures.

15. In the application according to claim 10 or 13, prior to gas storage or separation, it is also necessary to process the sp... 2 Guest molecules in the c-POC crystal cavity were removed by filtration, methanol washing, several methanol exchanges, and vacuum drying to obtain a white powdery form of sp with guest solvent molecules removed. 2 c-POC porous materials.

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