Method for adsorption and covalent grafting of guest molecules in two-dimensional porous covalent organic framework film and guest molecule modified two-dimensional porous covalent organic framework film
By depositing and heating two-dimensional porous covalent organic frame precursor molecules on metal substrates, forming a polylattice structure film and grafting the guest molecule on it, the problem of insufficient adsorption ability of the film to the guest molecule is solved, and efficient molecular recognition and modification are achieved.
Patent Information
- Application Number
- CN202411716461.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-03-21
AI Technical Summary
The two-dimensional porous covalent organic framework film has poor grafting and adsorption capabilities for guest molecules, which limits its application in the molecular recognition direction.
Selective covalent grafting is achieved by depositing precursor molecules of a two-dimensional porous covalent organic frame on a metal substrate and heating promotes the coupling reaction; then depositing guest molecules on the film and heating annealing treatment.
The grafting and adsorption ability of two-dimensional porous covalent organic framework film to guest molecules is improved, selective modification of guest molecules is achieved, and its molecular recognition ability is enhanced.
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Abstract
Description
Technical Field
[0001] The present application relates to the field of covalent organic framework technology, and in particular to a method for adsorbing and covalently grafting guest molecules in a two-dimensional porous covalent organic framework film, and a two-dimensional porous covalent organic framework film modified with guest molecules. Background Art
[0002] Covalent Organic Framework (COF) films are a class of highly ordered porous materials constructed by covalent bonds of light elements (such as hydrogen, carbon, nitrogen, oxygen and boron), with excellent thermal and chemical stability. Two-dimensional porous covalent organic framework films have the characteristics of low density, high specific surface area, easy modification and functionalization, and therefore show excellent application prospects in the fields of gas storage, gas separation, catalysis, energy storage materials, optoelectronics, sensing and drug delivery. The molecular recognition ability of COF can be improved by selectively grafting or adsorbing specific guest molecules on the two-dimensional porous covalent organic framework film.
[0003] However, due to the influence of various factors such as the pore size, chemical properties and molecular shape of the two-dimensional porous covalent organic framework film, the two-dimensional porous covalent organic framework film has poor grafting and adsorption ability for guest molecules, which limits the application of the two-dimensional porous covalent organic framework film in the direction of molecular recognition.
[0004] The above contents are only used to assist in understanding the technical solution of the present application and do not constitute an admission that the above contents are prior art. Summary of the invention
[0005] The main purpose of this application is to provide a method for adsorbing and covalently grafting guest molecules in a two-dimensional porous covalent organic framework film, and a two-dimensional porous covalent organic framework film modified with guest molecules, aiming to achieve the grafting and adsorption of guest molecules on the two-dimensional porous covalent organic framework film.
[0006] To achieve the above object, the present invention provides a method for adsorbing and covalently grafting guest molecules in a two-dimensional porous covalent organic framework film, comprising the following steps:
[0007] Providing a metal substrate, and depositing precursor molecules of a two-dimensional porous covalent organic framework on the metal substrate;
[0008] Heating the precursor molecules deposited on the metal substrate to obtain a two-dimensional porous covalent organic framework film, wherein the two-dimensional porous covalent organic framework film comprises: a hexagonal lattice structure;
[0009] Guest molecules are deposited on the two-dimensional porous covalent organic framework film, and a heating annealing treatment is performed to obtain a two-dimensional porous covalent organic framework film modified with guest molecules.
[0010] In one embodiment, the precursor molecules of the two-dimensional porous covalent organic framework include: 1,3,5-tri(4-iodophenyl)benzene molecules.
[0011] In one embodiment, the guest molecule includes a halogenated aromatic compound.
[0012] In one embodiment, the material of the metal substrate includes at least one of gold, silver, copper and platinum.
[0013] In one embodiment, the deposition method of the precursor molecules of the two-dimensional porous covalent organic framework and / or the guest molecules comprises: thermal evaporation.
[0014] In one embodiment, the substrate temperature when depositing the precursor molecules of the two-dimensional porous covalent organic framework is 180-200° C., and the deposition time is 5-120 mins;
[0015] And / or, the substrate temperature during deposition of the guest molecules is 180-200° C., and the deposition time is 5-120 mins.
[0016] In one embodiment, the vacuum degree during the deposition of the precursor molecules of the two-dimensional porous covalent organic framework and / or the guest molecules is less than or equal to 1×10 -8 mbar.
[0017] In one embodiment, the annealing temperature during the heating annealing treatment is 380-400° C., and the duration is 5-120 minutes;
[0018] And / or, the heating temperature when heating the precursor molecules deposited on the metal substrate is 380-400° C., and the heating time is 5-120 mins.
[0019] In one embodiment, the two-dimensional porous covalent organic framework film further comprises: at least one of a tetragonal lattice, a pentagonal lattice, a heptagonal lattice, an octagonal lattice and a enneagonal lattice structure.
[0020] The embodiment of the present application also provides a two-dimensional porous covalent organic framework film modified by a guest molecule, and the two-dimensional porous covalent organic framework film modified by a guest molecule is prepared by the above method.
[0021] One or more technical solutions proposed in the present application have at least the following technical effects: providing a method for adsorbing and covalently grafting guest molecules in a two-dimensional porous covalent organic framework film, by providing a metal substrate and depositing precursor molecules of the two-dimensional porous covalent organic framework on the metal substrate through the principle of molecular self-assembly; then heating the precursor molecules deposited on the metal substrate to promote the precursor molecules to undergo a coupling reaction, and epitaxially grow along the substrate surface to obtain a two-dimensional porous covalent organic framework film with a polycrystalline lattice structure; then depositing guest molecules on the two-dimensional porous covalent organic framework film, utilizing the polycrystalline lattice structure to achieve selective adsorption of guest molecules, and performing heating annealing treatment to allow the guest molecules to directly undergo an Ullmann coupling reaction with the main skeleton, complete selective covalent grafting, and obtain a two-dimensional porous covalent organic framework film modified with guest molecules, thereby achieving grafting and adsorption of guest molecules on the two-dimensional porous covalent organic framework film. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A flow chart of a method for adsorbing and covalently grafting guest molecules in a two-dimensional porous covalent organic framework film according to an embodiment of the present application;
[0023] Figure 2 The characterization results of Example 1 of this application are shown in FIG. Figure 1 ;
[0024] Figure 3 is the chemical reaction formula involved in Example 1 of the present application;
[0025] Figure 4 The characterization results of Example 1 of this application are shown in FIG. Figure 2 ;
[0026] Figure 5 The characterization results of Example 1 of this application are shown in FIG. Figure 3 ;
[0027] Figure 6 The characterization results of comparative example 1 of this application are shown in FIG. Figure 4 .
[0028] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.
[0030] Below, the method of adsorption and covalent grafting of guest molecules in a two-dimensional porous covalent organic framework film and the implementation method of the two-dimensional porous covalent organic framework film modified by the guest molecules of the present application are specifically disclosed with appropriate reference to the accompanying drawings. However, there are cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following descriptions are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.
[0031] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
[0032] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.
[0033] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.
[0034] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.
[0035] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.
[0036] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).
[0037] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and understandable, the technical solution of the present application is further described below in conjunction with the accompanying drawings and embodiments. However, the present application is not limited to the listed embodiments, and should also include any other known changes within the scope of the rights claimed in the present application.
[0038] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present application. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.
[0039] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.
[0040] Two-dimensional covalent organic frameworks (COFs) materials have great potential due to their large surface area, adjustable pore structure, and rich electronic properties. Therefore, they show excellent application prospects in the fields of gas storage, gas separation, catalysis, energy storage materials, optoelectronics, sensing, and drug delivery. The molecular recognition ability of COF can be improved by selectively grafting or adsorbing specific guest molecules on the two-dimensional porous covalent organic framework film. However, due to the influence of multiple factors such as the pore size, chemical properties, and molecular shape of the two-dimensional porous covalent organic framework film, the two-dimensional porous covalent organic framework film has poor grafting and adsorption capabilities for guest molecules, which limits the application of the two-dimensional porous covalent organic framework film in the direction of molecular recognition.
[0041] The present application provides a solution, specifically, a method for adsorbing and covalently grafting guest molecules in a two-dimensional porous covalent organic framework film, by providing a metal substrate, and depositing precursor molecules of a two-dimensional porous covalent organic framework on the metal substrate through the principle of molecular self-assembly; then heating the precursor molecules deposited on the metal substrate to promote the precursor molecules to undergo a coupling reaction, epitaxially grow along the substrate surface, and obtain a two-dimensional porous covalent organic framework film with a polycrystalline lattice structure; then depositing guest molecules on the two-dimensional porous covalent organic framework film, using the polycrystalline lattice structure to achieve selective adsorption of guest molecules, and performing heating annealing treatment to allow the guest molecules to directly undergo an Ullmann coupling reaction with the main skeleton, complete selective covalent grafting, and obtain a two-dimensional porous covalent organic framework film modified with guest molecules, thereby achieving grafting and adsorption of guest molecules on the two-dimensional porous covalent organic framework film. Annealing treatment is performed to remove the metal catalyst loaded on the surface of COFs, and obtain COFs whose electronic state and band gap can be observed and regulated to meet different application requirements.
[0042] Reference Figure 1 In a first aspect, an embodiment of the present application provides a method for adsorbing and covalently grafting guest molecules in a two-dimensional porous covalent organic framework film, comprising the following steps:
[0043] Step S10, providing a metal substrate, and depositing precursor molecules of a two-dimensional porous covalent organic framework on the metal substrate;
[0044] In a feasible embodiment, in order to realize the grafting and adsorption of guest molecules on the two-dimensional porous covalent organic framework film, it is necessary to first prepare the two-dimensional porous covalent organic framework film, and then provide a metal substrate, and deposit the precursor molecules of the two-dimensional porous covalent organic framework on the metal substrate. The metal substrate can not only promote the effective organization of molecules and support the two-dimensional porous covalent organic framework film, but also participate in the Ullmann coupling reaction at high temperature as a surface auxiliary catalyst.
[0045] The Ullmann reaction is an organic synthesis reaction in which halogenated aromatic compounds undergo a coupling reaction to form biaryls under the action of a catalyst. Metal substrates can enhance the interaction between reactant molecules by providing active sites, thereby improving reaction efficiency and selectivity.
[0046] In a feasible implementation, the material of the metal substrate includes: at least one of gold, silver, copper and platinum. The surfaces of the above materials have good flatness, and are therefore suitable as substrate materials for the two-dimensional porous covalent organic framework film.
[0047] Exemplarily, the material of the metal substrate includes: gold (111) single crystal; the gold (111) surface has a high degree of crystallinity and flatness, as well as atomic arrangement and electronic structure characteristics, which can form specific interactions with molecules adsorbed on its surface, and the diffusion barrier of the molecules on the gold (111) surface is relatively low. The low diffusion barrier helps the molecules move on the substrate surface and find the most energy stable arrangement, thereby forming a two-dimensional porous covalent organic framework film.
[0048] For example, the metal substrate may be subjected to argon ion bombardment and annealing treatment in advance.
[0049] Exemplarily, the precursor molecules of the two-dimensional porous covalent organic framework include: halogenated aromatic hydrocarbon compounds.
[0050] In one feasible embodiment, the precursor molecules of the two-dimensional porous covalent organic framework include: 1,3,5-tri(4-iodophenyl)benzene TIPB molecules. That is, TIPB molecules are used as precursor evaporation sources, and TIPB molecules are deposited on a metal substrate by thermal evaporation. Before the evaporation source is deposited, a de-impurity treatment can be performed, and small molecular impurities with low evaporation temperatures can be slowly evaporated by heating for 1-2 days until a pure precursor molecule evaporation source is obtained. By using TIPB molecules as precursor molecules, benzene ring coupling is promoted, and a two-dimensional porous covalent organic framework film with lattice pores of specific sizes is formed, specifically including: a hexagonal lattice structure.
[0051] In one feasible embodiment, the substrate temperature when depositing the precursor molecules of the two-dimensional porous covalent organic framework is 180-200° C., for example, 180° C., 182° C., 184° C., 186° C., 188° C., 190° C., 192° C., 194° C., 196° C., 198° C., 200° C., etc. At this temperature, the precursor evaporation source can be successfully evaporated.
[0052] In one feasible embodiment, the deposition time of the precursor molecules of the two-dimensional porous covalent organic framework is 5 to 120 minutes, for example, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes, 120 minutes, etc. Within this time, a single layer of molecules or a few layers of molecular coverage can be obtained.
[0053] In one feasible embodiment, the vacuum degree during the deposition of the precursor molecules of the two-dimensional porous covalent organic framework is less than or equal to 1×10 -8 mbar; Reducing contaminants on the surface of two-dimensional porous covalent organic framework films by deposition under ultra-vacuum conditions.
[0054] Step S20, heating the precursor molecules deposited on the metal substrate to obtain a two-dimensional porous covalent organic framework film;
[0055] In one feasible embodiment, the precursor molecules deposited on the metal substrate are heated to promote the occurrence of the Ullmann dehalogenation carbon-carbon coupling reaction, so that the crystal structure units of the COF grow epitaxially along the substrate surface to obtain a two-dimensional porous covalent organic framework film with a polycrystalline structure.
[0056] In a feasible embodiment, the two-dimensional porous covalent organic framework film includes: a hexagonal lattice structure, and at least one of a tetragonal lattice, a pentagonal lattice, a heptagonal lattice, an octagonal lattice and a enneagonal lattice structure. Among them, since the pore size of the tetragonal lattice and the pentagonal lattice is smaller than the molecular size, it is difficult to achieve guest molecule recognition and adsorption, while the hexagonal lattice structure and the heptagonal lattice structure can adsorb one guest molecule, and the octagonal lattice structure and the enneagonal lattice structure can adsorb at most two guest molecules. The two-dimensional porous covalent organic framework film prepared in the embodiment of the present application has a hexagonal lattice structure, so it can well achieve the adsorption of guest molecules.
[0057] In one feasible embodiment, the heating temperature when heating the precursor molecules deposited on the metal substrate is 380-400°C; for example, 380°C, 382°C, 384°C, 386°C, 388°C, 390°C, 392°C, 394°C, 396°C, 398°C, 400°C, etc.
[0058] In one feasible embodiment, the heating time when heating the precursor molecules deposited on the metal substrate is 5 to 120 minutes; for example, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes, 120 minutes, etc.
[0059] Step S30 , depositing guest molecules on the two-dimensional porous covalent organic framework film, and performing heating annealing treatment to obtain a two-dimensional porous covalent organic framework film modified with guest molecules.
[0060] In a feasible embodiment, a halogenated aromatic compound is used as an evaporation source, and a guest molecule is deposited on a two-dimensional porous covalent organic framework film by a thermal evaporation method. Since both the guest molecule and the host molecule (i.e., the two-dimensional porous covalent organic framework film) are halogenated aromatic compounds, the pore sizes and chemical properties of the two are compatible, and the two-dimensional porous covalent organic framework film has a polycrystalline structure, it is possible to selectively adsorb the guest molecule onto the two-dimensional porous structure; and then, by heating and annealing treatment, the guest molecule and the host skeleton directly undergo an Ullmann coupling reaction, and selective covalent grafting is completed to obtain a two-dimensional porous covalent organic framework film modified with a guest molecule, thereby realizing the grafting and adsorption of the guest molecule onto the two-dimensional porous covalent organic framework film.
[0061] Exemplarily, the guest molecule includes: 1,3,5-tri(4-iodophenyl)benzene molecule.
[0062] In one feasible embodiment, the substrate temperature during deposition of the guest molecules is 180-200° C., for example, 180° C., 182° C., 184° C., 186° C., 188° C., 190° C., 192° C., 194° C., 196° C., 198° C., 200° C., etc. At this temperature, the precursor evaporation source can be successfully evaporated.
[0063] In one feasible embodiment, the deposition time when depositing the guest molecules is 5 to 120 minutes, for example, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes, 120 minutes, etc. Under this time, a monolayer or a few layers of molecular coverage can be obtained.
[0064] In one embodiment, the vacuum degree during the deposition of the guest molecules is less than or equal to 1×10 -8 mbar; reducing contamination by deposition under ultra-vacuum conditions.
[0065] In one feasible embodiment, the annealing temperature during the heating annealing treatment is 380-400° C., for example, 380° C., 382° C., 384° C., 386° C., 388° C., 390° C., 392° C., 394° C., 396° C., 398° C., 400° C., etc. At this temperature, the adsorbed guest molecules and the host molecules can undergo a metal-catalyzed Ullmann deiodination polymerization reaction to form a covalent graft.
[0066] In one feasible embodiment, the duration of the heating annealing treatment is 5 to 120 minutes, for example, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes, 120 minutes, etc.
[0067] In this embodiment, a metal substrate is provided, and precursor molecules of a two-dimensional porous covalent organic framework are deposited on the metal substrate through the principle of molecular self-assembly; the precursor molecules deposited on the metal substrate are then heated to cause the precursor molecules to undergo a coupling reaction, and epitaxially grow along the substrate surface to obtain a two-dimensional porous covalent organic framework film with a polycrystalline structure; guest molecules are then deposited on the two-dimensional porous covalent organic framework film, the polycrystalline structure is used to achieve selective adsorption of the guest molecules, and a heating annealing treatment is performed to allow the guest molecules to directly undergo an Ullmann coupling reaction with the main skeleton, complete selective covalent grafting, and obtain a two-dimensional porous covalent organic framework film modified with guest molecules, thereby achieving grafting and adsorption of guest molecules on the two-dimensional porous covalent organic framework film. Annealing treatment is performed to remove the metal catalyst loaded on the surface of COFs, and COFs with observable and regulated electronic states and band gap conditions are obtained to meet different application requirements.
[0068] In order to enable the details and operations of the above embodiments of the present application to be clearly understood by those skilled in the art, and to significantly demonstrate the improved performance of the embodiments of the present application, the above technical solutions are illustrated by means of multiple embodiments below.
[0069] Example 1
[0070] (1) providing a gold (111) substrate (metal substrate), bombarding a gold single crystal substrate with an argon ion gun for 30 mins, and then thermally annealing to 500° C., repeating the above substrate cleaning steps 5 times to obtain a clean gold substrate; selecting TIPB as a precursor molecule, heating the molecular source to 120° C. for about two days to remove impurities and purify the precursor molecule;
[0071] (2) Depositing TIPB precursor molecules on a gold substrate by thermal evaporation, wherein the substrate temperature for thermal evaporation is 180°C, the deposition time is 5 min, and the vacuum degree is 1×10 -8 mbar; in situ imaging of the samples was performed by low-temperature high-resolution scanning tunneling microscopy (LT-STM), such as Figure 2 As shown, the self-assembly behavior of TIPB precursor molecules was observed, indicating that TIPB precursor molecules have been successfully evaporated on the surface of the gold substrate;
[0072] (3) The gold substrate was heated at 380°C for 5 min to promote the Ullmann coupling reaction. The precursor molecules were deiodinated to form carbon-carbon covalent bonds, thereby epitaxially growing a two-dimensional porous covalent organic framework film as the main molecule on the gold surface. The chemical reaction formula is as follows: Figure 3 As shown; the sample was characterized by in situ imaging using LT-STM, and the results are shown Figure 4 As shown, a two-dimensional porous COF with a single layer on the gold surface can be observed, and there are lattice units with different pore sizes in the two-dimensional porous COF;
[0073] (4) TIPB was again deposited onto the gold substrate as a guest molecule by thermal evaporation, wherein the substrate temperature for thermal evaporation was 180 °C, the deposition time was 5 min, and the vacuum degree was 1×10 -8 mbar; after deposition, the sample was characterized by in-situ imaging using LT-STM. Figure 5 As shown, it can be seen that the tetragonal lattice structure and the pentagonal lattice structure are difficult to adsorb guest molecules due to their small pore size; while the hexagonal lattice structure and the heptagonal lattice can adsorb one guest molecule; the octagonal lattice and the nine-gonal lattice can adsorb two guest molecules;
[0074] (5) After heating and annealing at 380°C for 5 min, a two-dimensional porous covalent organic framework film modified with guest molecules was obtained; the sample was characterized by in situ imaging using LT-STM, such as Figure 6 As shown, it can be seen that the tetragonal lattice and the pentagonal lattice cannot adsorb guest molecules and thus cannot achieve covalent grafting; the hexagonal lattice and the heptagonal lattice can covalently graft one guest molecule; the octagonal lattice and the nonagonal lattice can covalently graft two guest molecules, and a covalent connection is also formed between the two adsorbed guest molecules.
[0075] In summary, the embodiments of the present application realize the grafting and adsorption of guest molecules by the two-dimensional porous covalent organic framework film, and find that the adsorption process of the guest molecules by the two-dimensional porous covalent organic framework film is determined by the lattice pore size. The specific adsorption site is that the iodine atom of the guest molecule is located at the side chain to form an iodine-carbon bond to keep the system energy at the lowest. As for the grafting process, the adsorbed guest molecule forms a covalent connection with the side chain molecule of the host molecule (such as Figure 6 to maintain the most stable structure.
[0076] The above are only preferred embodiments of the present application, and do not limit the scope of the present application. For those skilled in the art, the present application may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of patent protection of the present application.
Claims
1. A method for adsorption and covalent grafting of guest molecules in a two-dimensional porous covalent organic framework film, characterized in that: The method comprises the following steps: Providing a metal substrate, and depositing precursor molecules of a two-dimensional porous covalent organic framework on the metal substrate; heating the precursor molecules deposited on the metal substrate to obtain a two-dimensional porous covalent organic framework film; Guest molecules are deposited on the two-dimensional porous covalent organic framework film, and a heating annealing treatment is performed to obtain a two-dimensional porous covalent organic framework film modified with guest molecules.
2. The method for adsorption and covalent grafting of guest molecules in a two-dimensional porous covalent organic framework film according to claim 1, characterized in that: The precursor molecules of the two-dimensional porous covalent organic framework include: 1,3,5-tri(4-iodophenyl)benzene molecules.
3. The method for adsorption and covalent grafting of guest molecules in a two-dimensional porous covalent organic framework film according to claim 1, characterized in that: The guest molecules include halogenated aromatic hydrocarbon compounds.
4. The method for adsorption and covalent grafting of guest molecules in a two-dimensional porous covalent organic framework film according to claim 1, characterized in that: The material of the metal substrate includes at least one of gold, silver, copper and platinum.
5. The method for adsorption and covalent grafting of guest molecules in a two-dimensional porous covalent organic framework film according to claim 1, characterized in that: The deposition method of the precursor molecules of the two-dimensional porous covalent organic framework and / or the guest molecules comprises: thermal evaporation method.
6. The method for adsorption and covalent grafting of guest molecules in a two-dimensional porous covalent organic framework film according to claim 1, characterized in that: The substrate temperature when depositing the precursor molecules of the two-dimensional porous covalent organic framework is 180-200° C., and the deposition time is 5-120 minutes; And / or, the substrate temperature during deposition of the guest molecules is 180-200° C., and the deposition time is 5-120 mins.
7. The method for adsorption and covalent grafting of guest molecules in a two-dimensional porous covalent organic framework film according to claim 1, characterized in that: The vacuum degree during the deposition of the precursor molecules of the two-dimensional porous covalent organic framework and / or the guest molecules is less than or equal to 1×10 -8 mbar.
8. The method for adsorption and covalent grafting of guest molecules in a two-dimensional porous covalent organic framework film according to claim 1, characterized in that: The annealing temperature during the heating annealing treatment is 380-400°C and the duration is 5-120 minutes; And / or, the heating temperature when heating the precursor molecules deposited on the metal substrate is 380-400° C., and the heating time is 5-120 mins.
9. The method for adsorption and covalent grafting of guest molecules in a two-dimensional porous covalent organic framework film according to claim 1, characterized in that: The two-dimensional porous covalent organic framework film comprises: a hexagonal lattice structure, and at least one of a tetragonal lattice, a pentagonal lattice, a heptagonal lattice, an octagonal lattice and a enneagonal lattice structure.
10. A two-dimensional porous covalent organic framework film modified with guest molecules, characterized in that: The guest molecule modified two-dimensional porous covalent organic framework film is prepared by the method according to any one of claims 1 to 9.