A carbon-carbon double bond bridged metal-salen based two-dimensional conjugated organic framework material and preparation method thereof

Abstract

The invention discloses a carbon-carbon double bond bridged metal-salen-based two-dimensional conjugated organic framework material and a preparation method thereof, comprising the following steps: step 1: adding a metal-salen salt functionalized with a reaction monomer formyl group, 2,4,6-trimethyl-1,3,5-triazine, an organic mixed solvent and a catalyst alkaline aqueous solution into an ampoule, step 2: sealing the ampoule with a butane combustible gas, transferring the ampoule into a constant temperature oven, and performing a heating reaction, step 3: after the heating reaction is completed, the ampoule is cooled, the precipitate is collected by suction filtration, the precipitate is washed, and dried to obtain an organic framework material salen-COF-M (M=Zn, Co, Ni, etc.). The COF material has high crystallinity, high specific surface area, uniform pore structure, absorption in the visible light range, excellent thermal stability and uniform two-dimensional layered morphology.

Description

Technical Field

[0001] The present invention relates to the technical field of covalent organic framework materials (COFs), and in particular to a carbon-carbon double bond-bridged metal-salen-based two-dimensional conjugated organic framework material and a preparation method thereof. Background Art

[0002] N,N'-bis(salicylidene)ethylenediamine(Salen) is one of the most representative advantageous ligands in coordination chemistry. Because it can coordinate with metal ions of different valence states, Salen complexes are effective catalysts in homogeneous catalysis and are widely used in olefin oxidation, ring-opening reaction and kinetic resolution of epoxides, DA reaction and other reactions. Introducing Salen into porous materials after heterogeneity can solve the shortcomings of traditional homogeneous Salen catalysts that are difficult to separate and recycle; the introduction of Salen functional building blocks can also give materials new functional properties, realizing the application of porous materials in heterogeneous catalysis, molecular recognition and separation, sensing and other fields.

[0003] Covalent organic frameworks (COFs) are a class of porous organic polymer materials with crystallinity and periodicity. They have the advantages of large specific surface area, rich pore structure, light weight, ordered structure, and adjustable pore size. They have good application prospects in photovoltaic materials, guest molecule adsorption, material transport, energy storage, photoelectric functions, and nanoreactors, and have therefore received widespread attention.

[0004] Therefore, using metal-salen as a ligand to synthesize a new type of crystalline material COFs through CC double bond bridging can effectively combine the advantages of both and further expand its application range, which has great research significance and application value. Summary of the invention

[0005] The purpose of the present invention is to provide a carbon-carbon double bond bridged metal-salen based two-dimensional conjugated organic framework material and a preparation method thereof, so as to prepare a porous covalent organic framework material based on metal-salen ligands with good crystallization and large specific surface area.

[0006] The object of the present invention is achieved through the following technical scheme: a carbon-carbon double bond bridged metal-salen-based two-dimensional conjugated organic framework material, the carbon-carbon double bond bridged metal-salen-based two-dimensional conjugated organic framework material is a COF synthesized by using a formyl-functionalized metal-salen complex and 2,4,6-trimethyl-1,3,5-triazine, the carbon-carbon double bond bridged metal-salen-based two-dimensional conjugated organic framework material is a trigonal crystal system, and the specific synthesis reaction formula is as follows;

[0007]

[0008] Furthermore, the specific surface area of ​​the carbon-carbon double bond bridged metal-salen based two-dimensional conjugated organic framework material is 1108 m 2 ·g -1 , the pore size distribution is mainly concentrated around 2.5nm.

[0009] A method for preparing a carbon-carbon double bond-bridged metal-salen-based two-dimensional conjugated organic framework material comprises the following steps:

[0010] Step 1: In a glove box with argon atmosphere, add the reaction monomer salen-M, 2,4,6-trimethyl-1,3,5-triazine, organic mixed solvent and catalyst alkaline aqueous solution into a round-bottom solvent ampoule;

[0011] Step 2: sealing the ampoule with butane combustible gas, and transferring the ampoule to a constant temperature oven for heating reaction;

[0012] Step 3: After the heating reaction is completed, the ampoule is cooled naturally to room temperature, and the precipitate is collected by vacuum filtration. The precipitate is washed with dichloromethane and methanol respectively, and then vacuum dried to finally obtain the organic framework material salen-COF-M;

[0013] The reaction temperature of the heating reaction is 90-110°C and the reaction time is 65-75 hours;

[0014] The vacuum drying in step 3 is carried out at a drying temperature of 55-65° C. and for a drying time of 8-12 hours.

[0015] Furthermore, the reaction monomer salen-M is a formyl-functionalized disalicylic aldehyde ethylenediamine-based metal complex, and M is a catalytically active metal ion Zn 2+ , Cu 2+ 、Co 2+ or Ni 2+ .

[0016] Furthermore, the organic mixed solvent is a mixture of 1,4-dioxane and ethanol, and the volume ratio of 1,4-dioxane to ethanol is 55:28.

[0017] Furthermore, the catalyst alkaline aqueous solution is a 1M sodium hydroxide aqueous solution, and the mixed organic solution:catalyst=83:17.

[0018] Furthermore, the reaction temperature of the heating reaction is 100° C. and the reaction time is 72 hours.

[0019] Furthermore, the drying temperature of the vacuum drying in step 3 is 60° C., and the drying time is 12 hours.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention uses a formyl-functionalized metal-salen complex as a core monomer for the first time to synthesize a carbon-carbon double bond-bridged two-dimensional COF under solvent thermal conditions. The COF material has high crystallinity, high specific surface area, uniform pore structure, absorption in the visible light range, excellent thermal stability and a uniform two-dimensional layered morphology.

[0022] The present invention optimizes the reaction conditions and synthesizes the COF using a formyl-functionalized metal-salen complex and 1,3,5-trimethyl-2,4,6-triazine, which has high crystallinity, high specific surface area, uniform pore structure and semiconductor properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the synthesis process of preparing the covalent organic framework material of the present invention;

[0024] Figure 2 It is the XRD characterization of the covalent organic framework material prepared by the present invention;

[0025] Figure 3 It is the infrared characterization of the covalent organic framework material prepared by the present invention;

[0026] Figure 4 It is the BET characterization of the covalent organic framework material prepared by the present invention;

[0027] Figure 5 This is a SEM picture of the covalent organic framework material prepared by the present invention. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] like Figure 1-5 As shown, the crystal structure of the metal-salen-based two-dimensional conjugated organic framework material bridged by carbon-carbon double bonds in the present invention is determined by powder X-ray diffraction and analyzed by theoretical simulation.

[0031] The porous structure of the metal-salen-based two-dimensional conjugated organic framework material bridged by carbon-carbon double bonds in the present invention is characterized by nitrogen adsorption and desorption test (Quantachrome autosorbi Q3 series fully automatic physical and chemical adsorption instrument): the characterization results obtained include nitrogen adsorption and desorption isotherms, BET specific surface area and pore size distribution.

[0032] Example 1: Synthesis of 5-tert-butyl-4-hydroxyisophthalaldehyde

[0033] Weigh 2-tert-butylphenol (4.50 g, 0.03 mol) and hexamethyltetramine (5.04 g, 0.036 mol) in a 50 mL flask, add 27 mL trifluoroacetic acid. Heat the solution to 120 ° C and reflux for 3 hours. After the solution is cooled to room temperature, add 27 mL 10% aq sulfuric acid, heat to 100 ° C again, and react for 2 hours. After the reaction is completed, adjust the solution to pH = 8 with saturated sodium carbonate aqueous solution, extract with ethyl acetate, stand and separate, combine the organic phases, wash with water, wash with salt, dry, concentrate under reduced pressure, and separate by column to obtain 5-tert-butyl-4-hydroxyisophthalaldehyde (3 g, yield 50%) as a yellow solid.

[0034] The structural characterization data of the product obtained in Example 1 are as follows: 1 H NMR (400MHz, Chloroform-d) δ12.40(s,1H),9.98(s,1H),9.92(s,1H),8.06(m,1H),8.00(m,1H),1.44(s,9H). 13C NMR (101MHz, cdcl 3 )δ196.82,189.92,166.08,139.86,135.38,133.82,128.45,120.27,31.59,28.97.

[0035] The structure of the product deduced from the above data is as follows:

[0036]

[0037] Example 2: Synthesis of formyl-functionalized salen

[0038] Add 5-tert-butyl-4-hydroxyisophthalaldehyde (3g, 15mmol) to a 250mL three-necked flask and stir to dissolve with 30mL of anhydrous methanol. Weigh (1R, 2R)-cyclohexanediamine (0.86g, 7.5mmol) and dissolve it in 10mL of anhydrous methanol, slowly drop it into the mixture, heat to reflux, and react overnight. After the reaction is completed, cool to room temperature, spin dry, and separate by column to obtain formyl functionalized salen as a yellow solid (3.675g, yield 50%).

[0039] The structural characterization data of the product obtained in Example 2 are as follows:

[0040] 1 H NMR (400MHz, Chloroform-d) δ9.73(s,2H),8.34(s,2H),7.77(s,2H),7.53(s,2H),3.51–3.37(m,2H),2.12–1.48(m,8H),1.39(s,18H). 13 C NMR (101MHz, cdcl 3 )δ190.38,167.24,165.01,139.03,133.58,130.28,126.97,117.85,71.52,34.95,32.67,29.05,24.11.

[0041] The structure of the product deduced from the above data is as follows:

[0042]

[0043] Example 3: Synthesis of formyl-functionalized salen-Zn

[0044] Add formyl functionalized salen (3.675 g, 7.5 mmol) into a 100 mL round-bottom flask, dissolve in 30 mL of anhydrous methanol, and then add Zn(OAc) 2 ·2H2 O (1.64 g, 7.5 mmol), stirred at room temperature overnight. After the reaction was completed, a light yellow solid precipitate was obtained by filtration. The precipitate was repeatedly washed with cold methanol and distilled water, and dried to obtain formyl-functionalized salen-Zn (2 g).

[0045] Example 4: Synthesis of COF

[0046] like Figure 1 It is shown that in a glove box with an argon atmosphere, 165 mg of the reaction monomer formyl functionalized salen-Zn, 25 mg of 1,3,5-trimethyl-2,4,6-triazine, 1.3 mL of 1,4-dioxane and 0.7 mL of anhydrous ethanol and 0.4 mL of a 1M sodium hydroxide aqueous solution are added to a 10 mL round-bottom solvent ampoule; the ampoule is sealed with butane combustible gas, and the ampoule is transferred to a 100° C. constant temperature oven for reaction for 72 hours;

[0047] After the heating reaction is completed, the ampoule is cooled naturally to room temperature, and the precipitate is collected by vacuum filtration. The precipitate is washed with dichloromethane and methanol respectively, and then vacuum dried at 60° C. for 12 hours to finally obtain the organic framework material salen-COF-Zn.

[0048] Embodiment 5:

[0049] like Figure 2 The powder X-ray diffraction pattern of the obtained salen-COF-Zn is consistent with the result of theoretical simulation. The results show that the prepared sample belongs to the trigonal system and has good crystallinity.

[0050] Embodiment 6:

[0051] like Figure 3 As shown, the infrared spectrum of the obtained salen-COF-Zn functionalized with formyl group shows obvious disappearance of -C=O group and formation of -C=C- group. The results show that the prepared sample is a COF bridged by carbon-carbon double bond.

[0052] Embodiment 7:

[0053] like Figure 4 As shown in the figure, the nitrogen adsorption isotherm and pore size distribution curve of the obtained salen-COF-Zn. The results show that the prepared salen-COF-Zn has a porous structure with a BET specific surface area of ​​1108m 2 ·g -1 , the pore size distribution is concentrated at 2.5nm.

[0054] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0055] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A carbon-carbon double bond-bridged metal-salen-based two-dimensional conjugated organic framework material, Features: The carbon-carbon double bond bridged metal-salen-based two-dimensional conjugated organic framework material is a COF synthesized by using a formyl-functionalized metal-salen complex and 2,4,6-trimethyl-1,3,5-triazine. The carbon-carbon double bond bridged metal-salen-based two-dimensional conjugated organic framework material is a trigonal crystal system, and the specific synthesis reaction formula is as follows; 。 2. A carbon-carbon double bond bridged metal-salen based two-dimensional conjugated organic framework material according to claim 1, Features: The specific surface area of ​​the carbon-carbon double bond-bridged metal-salen-based two-dimensional conjugated organic framework material is 1108 m 2 ·g -1 , the pore size distribution is mainly concentrated at 2.5 nm.

3. A method for preparing a carbon-carbon double bond bridged metal-salen based two-dimensional conjugated organic framework material according to claim 1 or 2, Features: The method comprises the following steps: Step 1: In a glove box with argon atmosphere, add the reaction monomer salen-M, 2,4,6-trimethyl-1,3,5-triazine, organic mixed solvent and catalyst alkaline aqueous solution into a round-bottom solvent ampoule; Step 2: sealing the ampoule with butane combustible gas, and transferring the ampoule to a constant temperature oven for heating reaction; Step 3: After the heating reaction is completed, the ampoule is cooled naturally to room temperature, and the precipitate is collected by vacuum filtration. The precipitate is washed with dichloromethane and methanol respectively, and then vacuum dried to finally obtain the organic framework material salen-COF-M; The reaction temperature of the heating reaction is 90-110°C and the reaction time is 65-75 hours; The vacuum drying in step 3 is carried out at a drying temperature of 55-65° C. and for a drying time of 8-12 hours.

4. A method for preparing a carbon-carbon double bond bridged metal-salen based two-dimensional conjugated organic framework material according to claim 3, Features: The organic mixed solvent is a mixture of 1,4-dioxane and ethanol, and the volume ratio of 1,4-dioxane to ethanol is 55:

28.

5. A method for preparing a carbon-carbon double bond bridged metal-salen based two-dimensional conjugated organic framework material according to claim 3, Features: The catalyst alkaline aqueous solution is a 1M sodium hydroxide aqueous solution.

6. A method for preparing a carbon-carbon double bond bridged metal-salen based two-dimensional conjugated organic framework material according to claim 3, Features: In step 2, the reaction temperature of the heating reaction is 100° C. and the reaction time is 72 hours.

7. A method for preparing a carbon-carbon double bond bridged metal-salen based two-dimensional conjugated organic framework material according to claim 3, Features: The drying temperature of the vacuum drying in step 3 is 60° C., and the drying time is 12 hours.

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