WO2023005143A1 - Two-dimensional supramolecular compound synthesized on the basis of 1,3,5-tri(4-carbonylphenyloxy)benzene, method therefor, and application thereof - Google Patents

Abstract

The present invention provides a two-dimensional supramolecular compound synthesized on the basis of 1,3,5-tri(4-carbonylphenyloxy)benzene, a preparation method therefor, and an application thereof. The method comprises adding 1,3,5-tri(4-carbonylphenyloxy)benzene, phen, and Cu(NO3)2·3H2O into an aqueous solution of acetonitrile, uniformly stirring and mixing, transferring the formed mixture into a reaction kettle having a polytetrafluoroethylene lining, performing heating to 110-130°C, maintaining the temperature for 60-84 hours, and performing cooling to 20-30°C at a speed of 3-8°C/h to obtain the two-dimensional supramolecular compound. Compared with the prior art, the present invention provides a relatively simple method for synthesizing the two-dimensional supramolecular compound, and the two-dimensional supramolecular compound synthesized by the method has relatively good degradation efficiency on dyes in water; and in addition, tests show that the two-dimensional supramolecular compound synthesized by the present invention is a stable and recoverable photocatalyst.

Description

Two-dimensional supramolecular compound synthesized based on 1,3,5-tris(4-carbonylphenyloxy)benzene and its method and application technical field

The invention relates to the treatment of dye-containing wastewater, in particular to a two-dimensional supramolecular compound synthesized based on 1,3,5-tris(4-carbonylphenyloxy)benzene and a method thereof, and a two-dimensional supramolecular compound based on the two-dimensional supramolecular compound Application to the degradation of dyes in water.

Background technique

Azo dyes containing -N=N- groups are the main pollutants in wastewater. Most dyes are difficult to be degraded by microorganisms due to their high stability, and may induce carcinogenic effects in living systems. At present, treatment technologies such as adsorption, membrane separation, and electrochemical degradation have been applied to the removal and treatment of dye wastewater to eliminate and reduce the lasting impact of dyes on biological systems. Photocatalysis is considered to be the most promising method to solve environmental problems. Since the photocatalytic properties of TiO2 were discovered in 1972, in order to explore the application of photocatalysts, people have developed technologies for photocatalytic water splitting and photocatalytic degradation of organic pollutants. Dyes containing rhodamine B (Rh B), methylene blue (MB), methylene orange (MO) and others are commonly used target pollutants in advanced oxidation processes.

As we all know, coordination polymers have been widely used because of their beautiful network structure and important potential application fields. Among numerous applications, coordination polymer-based photocatalysis has received extensive attention and improvements, mainly due to the fundamental need to deal with pollution problems. In addition, an increasing number of transition metal complexes and coordination polymers have been widely studied and discussed as photocatalysts, including their diverse network structures and controlled synthesis methods.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art, and to provide a method for synthesizing two-dimensional supramolecular compounds based on 1,3,5-tris(4-carbonylphenyloxy)benzene, based on the synthesis of two The dimensional supramolecular compound has a good degradation efficiency for dyes in water and is a stable and recyclable photocatalyst.

In order to achieve the above object, the present invention adopts the following technical solutions to achieve:

A method for synthesizing a two-dimensional supramolecular compound based on 1,3,5-tris(4-carbonylphenyloxy)benzene, the method comprising 1,3,5-tris(4-carbonylphenyloxy) ) benzene, phenol and Cu(NO ₃ ) ₂ ·3H ₂ O into the aqueous solution of acetonitrile, stir and mix evenly, transfer to a reaction kettle with Teflon lining, heat to 110-130°C and keep it warm 60-84 hours, then cooling down to 20-30°C at a rate of 3-8°C/h to obtain the two-dimensional supramolecular compound.

In a further technical solution, the mass ratio of 1,3,5-tris(4-carbonylphenyloxy)benzene, phenol and Cu(NO ₃ ) ₂ ·3H ₂ O is 1:(0.5-1) : (1.2-1.8).

In a further technical scheme, in the aqueous solution of acetonitrile, the volume ratio of acetonitrile to water is 1:(0.8-1.5).

Another aspect of the present invention provides a two-dimensional supramolecular compound synthesized by the above method.

Another aspect of the present invention also provides an application of the above-mentioned two-dimensional supramolecular compound to the degradation of dyes in water.

Compared with the prior art, the present invention provides a relatively simple method for synthesizing two-dimensional supramolecular compounds, and the two-dimensional supramolecular compounds synthesized by this method have better degradation efficiency for dyes in water; in addition, after Tests show that the two-dimensional supramolecular compound synthesized by the present invention is a stable and recyclable photocatalyst.

Other features and advantages of the present invention will be described in detail in the following specific embodiments.

Description of drawings

Fig. 1 shows the structure of compound 1 synthesized in Example 1 of the present invention; Fig. 1 (a) coordination geometry of Cu(II) center in compound 1; (b) three-dimensional supramolecular network perspective view 1 in compound 1 ; (c) hydrogen bond interactions between non-coordinating carboxyl groups of adjacent subunits and coordinated water molecules; (d) π-π interactions between phenol linkers on different chains;

Fig. 2 shows the thermogravimetric analysis curve diagram of compound 1 synthesized in Example 1 of the present invention;

Figure 3 shows the ultraviolet-visible diffuse reflectance spectrum (DRS) of compound 1 synthesized in Example 1 of the present invention;

Figure 4 shows the photocatalytic properties of compound 1 synthesized in Example 1 of the present invention to different dyes; Figure 4 (a)-(c) MO, the respective adsorption capacities of Rh B and MB solutions; (d) control group Viewpoints, adsorption capacity and catalytic performance of three dyes; (e) comparison of degradation efficiency of three dyes; (f) fitting data of ln(C ₀ /C) and t;

Figure 5 shows the PXRD patterns of compound 1 synthesized in Example 1 of the present invention under different conditions;

Figure ₆ shows the N adsorption-desorption isotherm of compound 1 synthesized in Example 1 of the present invention;

Fig. 7 shows the research of the catalytic reaction mechanism of the compound 1 that is synthesized in the embodiment of the present invention 1; Fig. 7 (a), (b) concentration change characteristic and catalytic change when scavenger exists; (c) ln (C ₀ /c) and time(t) fitting data; (d) the effect on MB degradation after 4 cycles of running;

Fig. 8 shows the molecular skeleton diagram of the dye in water in scheme 1 of the present invention.

FIG. 9 shows possible conversion paths for analyzing MB by LC-MS in Scheme 2 of the present invention.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further elucidated below in conjunction with specific embodiments.

In the present invention, a new two-dimensional compound was synthesized under mild conditions by selecting a tricarboxylic acid ligand and a nitrogen-containing ligand and Cu(NO ₃ ) ₂ , namely: [Cu ₂₍ HL) ₂ (H ₂ O ) ₂ (phen) ₂ ·H ₂ O] _n (H ₃ L=1,3,5-tris(4-carbonylphenyloxy)benzene, phen=1,10-phenanthroline)(1) .

In the following examples of the present invention, all other reagents were purchased and used without further purification. Elemental analyzes for C, H and N were performed on a Perkin-Elmer 240C analyzer.

FT-IR spectra were obtained on a VERTEX 70FT-IR spectrophotometer in the region 4000-600 cm-1.

On a D/MAX-3C diffractometer, under Cu-Kα radiation

and room temperature, powder x-ray diffraction (PXRD) experiments were carried out.

Luminescence measurements were performed at room temperature, and spectra were collected on a Perkin-Elmer LS50B fluorescence spectrometer.

UV-Vis spectra were measured on a spectrophotometer.

UV-Vis diffuse reflectance spectra of solid samples were collected _on a Cary 500 spectrophotometer using BaSO4 as reflectance standard.

Example 1

This example provides a method for synthesizing two-dimensional supramolecular compounds based on 1,3,5-tris(4-carbonylphenyloxy)benzene, specifically, 1,3,5-tris(4-carbonylphenyloxy)benzene oxy)benzene (0.05mmol, 0.024g), phenol (0.10mmol, 0.018g) and Cu(NO ₃ ) ₂ ·3H ₂ O (0.15mmol, 0.036g) were added to 10mL of acetonitrile in water (acetonitrile and water The volume ratio is 1:1); Stir and mix for 30 minutes, then put it into a 25mL reactor with a polytetrafluoroethylene liner, heat it to 120°C and keep it warm for 72 hours, then at a speed of 5°C/h The temperature was lowered to 25°C to obtain the product.

For convenience of description, the above product is defined as compound 1.

The following table 1 shows the crystallographic data of compound 1: IR (cm-1): 3466 (v); 3060 (m); 2583 (m); 2132 (m); 1712 (v); 1589 (v); 1496(vs); 1384(v); 1240(vs); 1137(m); 1004(m); 840(v); 727(m).

Crystal data of compound 1 in table 1

*R＝∑(F _o –F _c )/∑(F _o ),**wR ₂ ＝{∑[w(F _o ² –F _c ² ) ² ]/∑(F _o ² ) ² } ^1/2 .

Structural description of compound 1:

In compound 1, there is a Cu(II) cation, an HL ^2- anion, a coordinated water molecule, a phenol molecule, and a semi-free water molecule in each asymmetric subunit (as shown in Figure 1a) ;

Each Cu(II) center in compound 1 coordinates to two O atoms in two adjacent HL ^2- linkers, two N atoms from phen, and another oxygen atom from a coordinated water molecule, forming A tetrahedral geometry of {CuN ₂ O ₃ }. The basal plane is fixed by two carboxyl oxygen atoms and the N atoms of two phenol molecules, and the apex position is occupied by a coordinated water molecule (O10).

In compound 1, the partially deprotonated HL ^2- anion was bound to two metal ions on the carboxyl side in a μ1-η1:η0:η0:η0 coordination manner, while the COO ^- group in the middle was uncoordinated. The dihedral angles between the two benzene rings and the middle benzene ring are 21.5° and 18.1°, respectively. In this linkage, the monodentate coordination mode of HL ^2- anion and phenol forms a [Cu ₂ (HL) ₂ (H ₂ O) ₂ (phen) ₂ ] ring (as shown in Figure 1a); moreover, the phase of compound 1 Neighboring subunits are further connected by OHO interactions, generating parallel new layers along the bc plane (Fig. 1c). These layers are extended into a 3D supramolecular structure by the interaction of adjacent phenolic ligands (shown in Figures 1b and 1d).

Thermogravimetric analysis of compound 1:

The thermal stability of compound 1 was studied by thermogravimetric analysis (TGA). As shown in Figure 2, for compound 1, the first step of weight loss in the temperature range of 25-197 °C is due to the release of a lattice water molecule and Two coordinated water molecules; the weight loss over 240 °C can be attributed to the collapse of the lattice structure and the decomposition of organic ligands.

Measurement of photocatalytic reactions:

Compound 1 (40 mg) was added to 100 mL of methylene blue (MB)/methylene orange (MO)/rhodamine B (Rh B) solution (10 mg/L). The suspension was stirred for about 30 minutes in the dark, then continuously stirred under visible light irradiation (visible light λ > 400 nm) from a 300 W Xe lamp with a UV cut filter. The light intensity on the surface of the liquid is 3850W/m ² as measured by a PL-MW2000 photoelectric radiometer. At regular time intervals, aliquots of the reaction mixture were taken periodically and analyzed with a UV-Vis spectrophotometer at the absorption wavelengths of MB, MO and RhB.

Photocatalytic performance of compound 1:

The diffuse reflectance UV-vis data of compound 1 was collected to obtain the band gap (Eg). Since the point of intersection between the x-axis and the straight line is deduced from the straight line position of the absorption edge, the final calculation result, as shown in Fig. 3, Eg is estimated to be about 2.78eV.

By measuring the decomposition of MB, MO and Rh B under UV irradiation. First, the product components of MB, MO, and Rh B were extracted in the presence of photocatalysts, and their degradation efficiencies were listed (as shown in a, b, c, and e in Figure 4);

In accompanying drawing 4 of the present invention, Fig. 4a, b, c show respectively when compound 1 acts on MO, Rh B and MB, under different wavelength conditions, the absorbance of every 10 minutes illumination time, the absorbance is lower, Indicates that the more the dye is degraded. In Figure 4a, b, and c, the multiple curves correspond to the absorbance curves of different processing times, among which, for MO, as the processing time prolongs, the absorbance curve does not move down significantly, corresponding to 10.17 in Figure 4d % degradation rate; for MB, as the processing time prolongs, the absorbance curve is closer to the x-axis, that is, the absorbance decreases significantly, corresponding to the degradation rate of 46.87% in Figure 4d; for Rh B, as the processing time The prolongation of the absorbance curve decreased less than that of MB, corresponding to a degradation rate of 22.86% in Fig. 4d.

That is, from the results, compound 1 showed photocatalytic properties for MO, Rh B and MB, and the degradation rates were 10.17%, 22.86% and 46.87% within 100 minutes (as shown in Figure 4d).

Notably, compound 1 exhibited selective photocatalytic ability towards MB. Moreover, the inventors found that there are significant changes in the catalytic oxidation reaction with different catalyst dosage, dye concentration, metal effect, light source and irradiation time.

All data were fitted with pseudo-first-order kinetic equations to obtain and explore the catalytic reaction rate (Fig. 4d). Kinetic rate constants (k) are calculated using the usual linear plot. ln(C ₀ /C) has a good linear relationship with the reaction time (t). The k values of MO, Rh B and MB in the presence of photocatalysts are 0.00107min ^-1 , 0.00247min ^-1 and 0.0610min ^-1 , respectively (Fig. 4f and Table 2). In addition, the inventors also explored the cycle performance characteristics of compound 1. Even after four cycles of experiments, it was found that the catalytic performance of the catalyst did not decrease significantly (Fig. 7d). The PXRD of compound 1 did not change significantly during the 4 cycles (Figure 5). The present results demonstrate that compound 1 can serve as a stable and recyclable photocatalyst.

Table 2: Different fitting parameters for the pseudo-first-order kinetic equation

In addition, the inventors studied the N ₂ adsorption-desorption isotherm of compound 1 (Figure 6), and obtained the Brunauer-Emmett-Teller surface area of compound 1 as 7.44 m ² g ^-1 .

By analyzing its structural characteristics (0.22nm for 1), as shown in Figure 8, the size of the MO dye is 1.54nm×0.48nm×0.28nm, the size of the MB dye is 1.38nm×0.64nm×0.21nm, and the Rh B dye The size of is 1.56nm × 1.35nm × 0.42nm (Scheme 1), they are larger than the crystal pores, so they cannot enter the pores of compound 1. Based on the aforementioned correlation between the structural features of material channels and the size of dye molecules, we hypothesize that the catalytic reaction mainly occurs on the surface of the catalyst.

In order to explore and monitor the mechanism of the catalytic reaction, the inventors performed a series of trapping and trapping experiments. Three scavengers, benzoquinone (BQ), tert-butanol (TBA) and ammonium oxalate (AO), were selected in each degradation process (Fig. 7a-7b). The data show that scavengers can effectively induce and reduce the process of catalytic reactions. The performance of MB drops significantly, from 93.64% to 68.38% (Fig. 7c). During the catalytic process, the OH- radical captures H+ and becomes OH in compound 1. The results show that:·OH is a main active oxidative radical in the MB photodecomposition system.

In order to further explore the decomposition intermediates that may be produced during MB degradation, LC-MS method was used to study them. Based on the present spectrum analysis, a possible degradation mechanism was speculated in Scheme 2. In the first pathway, the MB molecule starts from an amination reaction, forming intermediates at m/ z 269 and 255. The intermediate of formula 227 is formed by demethylation and/or oxidation of intermediate 241. Based on its strong oxidation ability towards OH, N/S heterocycles were generated and many subsequent decomposition products were detected. Scheme 2 (shown in Figure 9) lists and discusses the most similar degradation pathways.

The basic principles, main features and characteristics of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible which fall within the scope of the claimed invention. The scope of the claimed invention is defined by the appended claims and their equivalents.

Claims (5)

1. A method for synthesizing a two-dimensional supramolecular compound based on 1,3,5-tris(4-carbonylphenyloxy)benzene, characterized in that the method comprises 1,3,5-tris(4-carbonyl Phenyloxy)benzene, phenol and Cu(NO ₃ ) ₂ ·3H ₂ O were added to the aqueous solution of acetonitrile, stirred and mixed evenly, then transferred to a reaction kettle with a polytetrafluoroethylene liner, heated to 110- 130°C for 60-84 hours, then cooling down to 20-30°C at a rate of 3-8°C/h to obtain the two-dimensional supramolecular compound.
2. The method according to claim 1, characterized in that the mass ratio of 1,3,5-tris(4-carbonylphenyloxy)benzene, phenol and Cu(NO ₃ ) ₂ ·3H ₂ O is 1 :(0.5-1):(1.2-1.8).
3. The method according to claim 1, characterized in that, in the aqueous solution of acetonitrile, the volume ratio of acetonitrile to water is 1:(0.8-1.5).
4. A two-dimensional supramolecular compound synthesized by the method according to any one of claims 1-3.
5. An application of the two-dimensional supramolecular compound according to claim 4 to the degradation of dyes in water.

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