Eutectic material based on organic macrocyclic aromatic hydrocarbon as well as preparation method and application of eutectic material

Abstract

The invention is applicable to the technical field of eutectic materials, and provides an organic macrocyclic aromatic hydrocarbon-based eutectic material and a preparation method and application thereof, the eutectic material is a metastable material EtLP6-F4TCNQ alpha, and is prepared by taking oblique tower aromatic hydrocarbon as a subject and electron-deficient 2, 3, 5, 6-tetrafluoro-7, 7, 8, 8-tetracyanodimethyl p-benzoquinone as an object, and carrying out co-crystallization on the oblique tower aromatic hydrocarbon and the 2, 3, 5, 6-tetrafluoro-7, 7, 8, 8-tetracyanodimethyl p-benzoquinone to obtain the organic macrocyclic aromatic hydrocarbon-based eutectic material. And carrying out mechanical grinding on 2, 3, 4, 5, 6, 8-tetracyanodimethyl p-benzoquinone. According to the method, two or more organic molecules are directly mixed and induced to form the eutectic structure through simple mechanical grinding operation, the method is efficient, low in cost and easy for large-scale production, the eutectic material with the metastable structure is prepared, and the metastable structure shows higher sensitivity and faster response speed in gasochromic detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of eutectic materials, and particularly relates to a eutectic material based on organic macrocyclic aromatic hydrocarbons, a preparation method thereof, and an application thereof. Background Art

[0002] Fatty aldehydes have a high degree of similarity in structure, mainly reflected in their functional groups and the arrangement of carbon chains. Fatty aldehyde compounds all contain a common functional group - aldehyde group (-CHO), and the aldehyde group is always located at the end of the carbon chain. Starting from acetaldehyde, as the carbon chain length increases, they are propionaldehyde (C3H6O), butyraldehyde (C4H8O), valeraldehyde (C5H 10 O), and hexanaldehyde (C6H 12 O). Their carbon chains are all straight-chain structures, and the carbon atoms are connected by single bonds to form a linear molecular skeleton. This structural similarity not only makes them show many common points in chemical properties, such as being prone to nucleophilic addition reactions and oxidation reactions, but also makes them very close in physical properties. For example, most of them are colorless liquids at room temperature and have similar pungent odors.

[0003] However, it is precisely this high degree of structural similarity that makes it quite difficult to visually detect and distinguish these fatty aldehydes. First of all, these compounds are usually colorless liquids at room temperature, and there is almost no difference in appearance, so they cannot be visually distinguished by color or morphology; secondly, low-molecular-weight fatty aldehydes (such as acetaldehyde and propionaldehyde) have high volatility, and their odors are very similar, all with pungency, which makes it unreliable to distinguish them by smell; in addition, due to their similar chemical properties, many conventional chemical detection methods (such as color reactions with certain reagents) often cannot effectively distinguish them because these reactions usually rely on the presence of the aldehyde group, and the aldehyde group is the same in all fatty aldehydes; finally, when the concentrations of these compounds are low, conventional detection methods may not provide sufficient sensitivity, further increasing the difficulty of detection.

[0004] The organic co-crystal strategy has significant advantages in the field of gasochromic detection and has become a research hotspot in materials science and sensor technology. Organic co-crystals are crystalline materials formed by two or more organic molecules through non-covalent interactions (such as hydrogen bonds, π-π stacking, etc.). Their core advantage lies in the precise regulation of material properties through molecular design. In gasochromic detection, this strategy can design highly sensitive and selective detection materials for specific gas molecules. For example, by introducing specific functional groups, the interaction between the material and the target gas molecule can be enhanced, improving the detection performance. In addition, organic co-crystals have fast responsiveness and reversibility. Gas molecules can quickly diffuse into the crystal interior and trigger color changes, and this change is usually reversible, enabling the material to be reused. The color change is obvious, facilitating observation by the naked eye or simple optical devices, and is suitable for real-time and on-site detection.

[0005] Although organic co-crystal materials exhibit many advantages in the field of gasochromism, there are still some significant limitations and drawbacks in their practical applications. First of all, the preparation process of organic co-crystal materials is usually relatively complex, requiring precise control of reaction conditions (such as solvent selection, temperature, concentration, etc.), and often takes a long time and is costly. For example, traditional solution methods or vapor diffusion methods require multiple crystallization and purification steps, which not only increase the preparation difficulty but also limit the feasibility of large-scale production. Secondly, the structural stability of organic co-crystal materials is poor and is easily affected by environmental factors (such as humidity, temperature), resulting in performance degradation or failure. In addition, although organic co-crystal materials have high sensitivity and selectivity to certain gases, their response range is still relatively limited, making it difficult to meet the detection requirements of multiple gases simultaneously. There are also certain problems with the reusability and long-term stability of organic co-crystal materials. Performance attenuation or structural damage may occur after multiple uses. Summary of the Invention

[0006] The purpose of the embodiments of the present invention is to provide a co-crystal material based on organic macrocyclic aromatic hydrocarbons, aiming to solve the problems proposed in the above background technology.

[0007] The embodiments of the present invention are implemented as follows. A co-crystal material based on organic macrocyclic aromatic hydrocarbons, the co-crystal material is a metastable material EtLP6-F4TCNQα, which uses skewed tower arene as the host and electron-deficient 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-benzoquinodimethane as the guest.

[0008] Another purpose of the embodiments of the present invention is to provide a preparation method for a co-crystal material based on organic macrocyclic aromatic hydrocarbons, including the following steps: Mechanically grind skewed tower arene (EtLP6) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-benzoquinodimethane (F4TCNQ).

[0009] Preferably, the molar ratio of the skew-tower aromatic hydrocarbon to 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane is 1:2.5-3.5.

[0010] Preferably, the molar ratio of the skew-tower aromatic hydrocarbon to 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane is 1:3.

[0011] Preferably, the time of mechanical grinding is 25-35 min.

[0012] Another object of the embodiments of the present invention is to provide an application of a co-crystal material based on organic macrocyclic aromatic hydrocarbons in the detection of aliphatic aldehydes.

[0013] Preferably, the co-crystal material based on organic macrocyclic aromatic hydrocarbons is placed in a container containing an aliphatic aldehyde solution, and gasochromic detection is carried out on aliphatic aldehydes with different chain lengths. The color deepens in short-chain acetaldehyde, propionaldehyde, and butyraldehyde, and the color fades in long-chain valeraldehyde and hexanal.

[0014] In the embodiments of the present invention, through simple mechanical grinding operations, two or more organic molecules are directly mixed and induced to form a co-crystal structure, without complex solvent treatment or long crystallization processes. This method is efficient, low-cost, and easy to scale up production. At the same time, a co-crystal material with a metastable structure can be prepared. This metastable structure exhibits higher sensitivity and faster response speed in gasochromic detection. In addition, the mechanical grinding method can also precisely control the material properties by adjusting the grinding conditions (such as time, force), thereby broadening its application range. Description of the Drawings

[0015] Figure 1 Schematic diagram of the solid-gas adsorption device provided by the embodiments of the present invention; Figure 2 1H NMR spectrum of EtLP6 after adsorbing acetaldehyde provided by the embodiments of the present invention; Figure 3 1H NMR spectrum of EtLP6 after adsorbing propionaldehyde provided by the embodiments of the present invention; Figure 4 1H NMR spectrum of EtLP6 after adsorbing butyraldehyde provided by the embodiments of the present invention; Figure 5 1H NMR spectrum of EtLP6 after adsorbing valeraldehyde provided by the embodiments of the present invention; Figure 6 1H NMR spectrum of EtLP6 after adsorbing hexanal provided by the embodiments of the present invention; Figure 7TG and DSC curves of EtLP6 provided by the embodiments of the present invention after exposure to aliphatic aldehyde vapors (a is the TG and DSC curves of EtLP6 after adsorbing acetaldehyde; b is the TG and DSC curves of EtLP6 after adsorbing propionaldehyde); Figure 8 TG and DSC curves of EtLP6 provided by the embodiments of the present invention after exposure to aliphatic aldehyde vapors (a is the TG and DSC curves of EtLP6 after adsorbing butyraldehyde; b is the TG and DSC curves of EtLP6 after adsorbing valeraldehyde; c is the TG and DSC curves of EtLP6 after adsorbing hexanal); Figure 9 Top view, side view and two-dimensional packing diagrams of EtLP6 and aliphatic aldehyde crystals provided by the embodiments of the present invention (a is the top view, side view and two-dimensional packing diagrams of EtLP6 and acetaldehyde crystals; b is the top view, side view and two-dimensional packing diagrams of EtLP6 and propionaldehyde crystals; c is the top view, side view and two-dimensional packing diagrams of EtLP6 and butyraldehyde crystals; d is the top view, side view and two-dimensional packing diagrams of EtLP6 and valeraldehyde crystals; e is the top view, side view and two-dimensional packing diagrams of EtLP6 and hexanal crystals); Figure 10 PXRD (a) and single crystal simulated XRD (b) of EtLP6 adsorbed with aliphatic aldehyde provided by the embodiments of the present invention; Figure 11 Schematic diagram of the preparation of EtLP6-F4TCNQα provided by the embodiments of the present invention; Figure 12 X-ray diffraction spectra of EtLP6, F4TCNQ and EtLP6-F4TCNQα provided by the embodiments of the present invention; Figure 13 Fourier infrared spectra of EtLP6, F4TCNQ and EtLP6-F4TCNQα provided by the embodiments of the present invention; Figure 14 UV-Vis diffuse reflectance spectra of EtLP6, F4TCNQ and EtLP6-F4TCNQα provided by the embodiments of the present invention; Figure 15 Gasochromic behavior of EtLP6-F4TCNQα in aliphatic aldehydes provided by the embodiments of the present invention; Figure 16 UV-Vis diffuse reflectance spectra of EtLP6-F4TCNQα after exposure to acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde and hexanal vapors provided by the embodiments of the present invention; Figure 17Analysis of the interaction force between EtLP6 and fatty aldehydes provided by the embodiments of the present invention (a is the analysis of the interaction force between EtLP6 and propionaldehyde; b is the analysis of the interaction force between EtLP6 and butyraldehyde; c is the analysis of the interaction force between EtLP6 and valeraldehyde; d is the analysis of the interaction force between EtLP6 and hexanal); Figure 18 Schematic diagram of the eutectic situation of EtLP6 and F4TCNQ provided by the embodiments of the present invention (a is the single crystal structure of EtLP6 and F4TCNQ; b is the analysis of the interaction force between EtLP6 and F4TCNQ; c is the stacking mode of the EtLP6+F4TCNQ eutectic in the ab and bc planes respectively); Figure 19 Simulated XRD spectrum of the EtLP6+F4TCNQ eutectic (a) and XRD spectrum of EtLP6-F4TCNQα after exposure to the vapor of each fatty aldehyde (b) provided by the embodiments of the present invention; Figure 20 1H NMR spectrum of EtLP6-F4TCNQα after exposure to acetaldehyde provided by the embodiments of the present invention; Figure 21 1H NMR spectrum of EtLP6-F4TCNQα after exposure to propionaldehyde provided by the embodiments of the present invention; Figure 22 1H NMR spectrum of EtLP6-F4TCNQα after exposure to butyraldehyde provided by the embodiments of the present invention; Figure 23 1H NMR spectrum of EtLP6-F4TCNQα after exposure to valeraldehyde provided by the embodiments of the present invention; Figure 24 1H NMR spectrum of EtLP6-F4TCNQα after exposure to hexanal provided by the embodiments of the present invention. Detailed implementation manners

[0016] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] To analyze the adsorption behavior of EtLP6 towards fatty aldehydes, only when EtLP6 has an adsorption behavior towards fatty aldehydes can there be a possibility of gasochromic applications. In the embodiments of the present invention, the adsorption behavior of EtLP6 towards fatty aldehydes was first studied by the solid-gas adsorption method. The solid-gas adsorption device is as Figure 1 shown. 3 mg of EtLP6 was spread flat on the bottom of a 2 mL uncovered vial and placed in a 20 mL covered vial containing 20 µL of fatty aldehyde solution. The specific adsorption amount was measured by 1H NMR spectrum and thermogravimetry; The 1H NMR spectrum of EtLP6 measured after exposure to fatty aldehyde vapor is as follows Figures 2 to 6 As shown, it can be judged from the NMR integration that EtLP6 can adsorb 0.5 equivalent of acetaldehyde, 1 equivalent of propionaldehyde, butyraldehyde, valeraldehyde and hexanal respectively; The thermogravimetric and differential thermal scanning curves are as follows Figures 7 to 8 As shown, it can be seen that before melting, EtLP6 has an endothermic behavior of releasing solvent; In addition, EtLP6 grew corresponding crystals in different fatty aldehyde solutions. As shown Figure 9 In the crystal of EtLP6 and acetaldehyde, EtLP6 presents a bowl-like structure, and one molecule of acetaldehyde exists in the cavity of EtLP6. The crystal presents a two-dimensional stacking mode on the ac plane; the crystal of EtLP6 and propionaldehyde is similar to that of acetaldehyde, and fatty aldehyde molecules all exist in the cavity of EtLP6. However, the difference is that the complexation ratio of EtLP6 and propionaldehyde is 1:2, and the stacking on the bc plane presents a two-dimensional mode similar to that of acetaldehyde; while the complexation modes of EtLP6 with butyraldehyde, valeraldehyde and hexanal are similar. It can be seen from the top view and side view that the aldehyde is sandwiched between two EtLP6s, and from the stacking diagram, the aldehyde molecules are fixed in the cavity assembled by EtLP6; As shown Figure 10 By single crystal XRD of EtLP6 and fatty aldehyde, the corresponding simulated XRD is derived, which matches well with the XRD measured by actual solid-gas adsorption.

[0018] EtLP6 used in the examples of the present invention was prepared with reference to the content in the prior art of "Jia-Rui Wu and Ying-Wei Yang, High-Performance n-Hexane Purification by Nonporous Adaptive Crystals of LeaningPillar[6]arene, CCS Chem. 2021, 3, 836–843", and the specific process will not be elaborated here; The CAS number of F4TCNQ is 29261-33-4; purchased from Aladdin Chemistry; product number: D0504030010.

[0019] The following describes the specific implementation of the present invention in detail with specific examples.

[0020] Example 1, A eutectic material based on organic macrocyclic aromatic hydrocarbons, the preparation process of which is as follows Figure 11As shown, the specific process is as follows: Take 89.32 mg (0.1 mmol) of EtLP6 and 80.16 mg (0.3 mmol) of F4TCNQ, grind them in an agate mortar for 30 min to obtain metastable EtLP6-F4TCNQα.

[0021] Characterization and morphology analysis of EtLP6-F4TCNQα: X-ray diffraction spectroscopy tests were performed on EtLP6, F4TCNQ, and EtLP6-F4TCNQα respectively, and the results are as Figure 12 shown. It can be clearly seen that the spectrum of EtLP6-F4TCNQα contains the characteristic peaks of EtLP6 and F4TCNQ, indicating the successful preparation of the composite material; Fourier transform infrared spectroscopy is as Figure 13 shown. Compared with F4TCNQ, the stretching vibration peak of C≡N in the spectrum of EtLP6-F4TCNQα blue-shifts from 2227 cm -1 to 2222 cm -1 , and the stretching vibration peaks of C-F also shift from 1344, 974, and 802 cm -1 to 1338, 970, and 794 cm -1 respectively. The bending vibration peak and symmetric stretching vibration peak of C-F also undergo blue-shift, which is mainly due to the charge transfer interaction generated after the combination of F4TCNQ and EtLP6, resulting in the elongation and weakening of the C-F bond; Ultraviolet-visible diffuse reflection spectroscopy is as Figure 14 shown. EtLP6 has no absorption in the visible region, the visible light absorption range of F4TCNQ is around 550 nm, while a charge transfer (CT) absorption band up to 1400 nm appears in the spectrum of EtLP6-F4TCNQα, indicating again the existence of charge transfer interaction between the host and guest, and proving the successful preparation of the metastable state.

[0022] Analysis of the gasochromic behavior of EtLP6-F4TCNQα in aliphatic aldehydes: Using the device as Figure 1 shown, spread 3 mg of EtLP6-F4TCNQα on the bottom of a 2 mL uncovered vial, place it in a 20 mL capped vial containing 20 µL of aliphatic aldehyde solution, and perform gasochromic detection on aliphatic aldehydes with different chain lengths; As Figure 15 shown, the color of EtLP6-F4TCNQα deepens in short-chain aliphatic aldehydes such as acetaldehyde, propionaldehyde, and butyraldehyde, and lightens in long-chain valeraldehyde and hexanal; The UV-vis spectrum is as Figure 16As shown, its test results are consistent with the color change. Compared with EtLP6-F4TCNQα, after being exposed to short-chain fatty aldehydes, its absorption intensity of visible light is significantly enhanced. After being exposed to long-chain fatty aldehydes, the original CT absorption band of the metastable state disappears, corresponding to the color change; To explore the mechanism of this color-changing behavior, a eutectic of EtLP6 and F4TCNQ was grown using dichloromethane and methylcyclohexane as conditions, and the intermolecular forces in the crystal were analyzed: First, the interaction between EtLP6 and fatty aldehydes was analyzed. As Figure 17 shown, propionaldehyde is mainly fixed in the cavity of EtLP6 through C-H···π interactions, while butyraldehyde, valeraldehyde, and hexanal are complexed with EtLP6 not only through C-H···π interactions but also through C-H···O interactions; for the eutectic of EtLP6 and F4TCNQ, as Figure 18 shown, as can be seen from Figure 18 (a), the complexation ratio of EtLP6 and F4TCNQ is 1:2. Figure 18 (b) shows that one F4TCNQ is complexed with EtLP6 through C-H···N interactions, while the other F4TCNQ is complexed with EtLP6 not only through C-H···N interactions, and the F atom on F4TCNQ provides the C-H···F interaction between the two. Figure 18 (c) is the topology of the EtLP6+F4TCNQ eutectic in the ab and bc planes respectively, both showing a host-guest interlaced two-dimensional planar structure; the XRD patterns of the metastable EtLP6-F4TCNQα after exposure to various fatty aldehyde vapors are as Figure 19 shown. It can be seen from the figure that the XRD patterns of EtLP6-F4TCNQα after exposure to acetaldehyde, propionaldehyde, and butyraldehyde are similar to those of the single-crystal simulated EtLP6+F4TCNQ eutectic; the NMR H spectrum is as Figures 20 to 24 shown. The metastable state does not adsorb acetaldehyde, propionaldehyde, and butyraldehyde. Therefore, the metastable state is promoted to form a eutectic structure in these three fatty aldehyde vapors. Compared with fatty aldehydes, the binding ability of F4TCNQ to EtLP6 is stronger. Therefore, fatty aldehydes provide the driving force for the further close binding of EtLP6 and F4TCNQ. However, after exposure to valeraldehyde and hexanal vapors, the XRD pattern of the metastable state matches well with the XRD of EtLP6 and valeraldehyde and hexanal, and the color of the metastable state becomes lighter. The NMR hydrogen spectrum also shows that the metastable state adsorbs one equivalent of valeraldehyde or hexanal, indicating that valeraldehyde and hexanal successfully disrupt the charge transfer interaction between EtLP6 and F4TCNQ by binding to EtLP6.

[0023] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A eutectic material based on organic macrocyclic aromatic hydrocarbons, characterized in that: The eutectic material is a metastable material EtLP6-F4TCNQα, which uses skewed tower arene as the host and electron-deficient 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-benzoquinodimethane as the guest.

2. A preparation method of a eutectic material based on organic macrocyclic aromatic hydrocarbons as described in claim 1, characterized in that, It includes the following steps: Mechanically grind skewed tower arene and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-benzoquinodimethane.

3. The preparation method of the cocrystal material based on organic macrocyclic aromatic hydrocarbons according to claim 2, characterized in that, The molar ratio of the skewed tower arene to 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-benzoquinodimethane is 1:2.5 - 3.

5.

4. The method for preparing a eutectic material based on organic macrocyclic aromatic hydrocarbons according to claim 3, characterized in that: The molar ratio of the skewed tower arene to 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-benzoquinodimethane is 1:

3.

5. The preparation method of the cocrystal material based on organic macrocyclic aromatic hydrocarbons according to claim 2, characterized in that, The time for the mechanical grinding is 25 - 35 min.

6. Application of a eutectic material based on organic macrocyclic aromatic hydrocarbons as described in claim 1 in the detection of aliphatic aldehydes.

7. The application according to claim 6, wherein Place the eutectic material based on organic macrocyclic aromatic hydrocarbons in a container containing an aliphatic aldehyde solution, and conduct gasochromic detection on aliphatic aldehydes with different chain lengths. The color deepens in short-chain acetaldehyde, propionaldehyde, and butyraldehyde, and the color fades in long-chain valeraldehyde and hexanal.

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