A compound based on 1,10-phenanthroline, its synthetic method, and its applications.

Abstract

This invention designs and synthesizes a compound based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid, which is obtained in one step via the Suzuki-Miyaura reaction. This method has the advantages of mild reaction conditions, simple reaction steps, and high product yield. Due to the intermolecular C-H…π interactions, the compound forms a three-dimensional network structure with cavities in the crystalline state. This gives the small molecule compound the same excellent properties as traditional macrocyclic aromatic hydrocarbons, allowing it to self-assemble into non-covalent molecular channels for adsorbing and encapsulating benzene-based pollutants without any induction. The adsorption process of this invention has low energy consumption, short adsorption time, low equipment requirements, and the selected crystalline material is easy to synthesize, resulting in high yield, strong stability, high adsorption capacity for benzene-based pollutants, and good adsorption effect.

Description

Technical Field

[0001] This invention belongs to the field of organic synthetic chemistry technology. It relates to a compound based on 1,10-phenanthroline, its synthetic method, and its application. Background Technology

[0002] Supramolecular chemistry, as an emerging interdisciplinary field, combines organic chemistry, analytical chemistry, inorganic chemistry, and polymer chemistry. It mainly studies the molecular aggregates with specific functions formed between molecules through non-covalent interactions such as hydrogen bonding, metal coordination, host-guest interaction, and π-π stacking.

[0003] 1,10-Phenanthroline (phen) is one of the most commonly used ligands in coordination chemistry due to its strong affinity for metals in various oxidation states. Its robust and rigid polyaromatic structure makes it attractive in many fields, including luminescent coordination scaffolds, catalysis, sensors, and therapeutics. In short, 1,10-phenanthroline is used in almost every aspect of chemistry. One of its fascinating aspects is that each carbon pair possesses specific reactivity, allowing for the functionalization of each pair with different groups to form multifunctional arrays. Furthermore, each position in these pairs can be differentiated, resulting in asymmetric systems with immense versatility.

[0004] Carbazole, also known as 9-azafluorene or iminodiphenylene, is mainly used in the manufacture of dyes, chemical reagents, explosives, insecticides, lubricants, rubber antioxidants, etc.

[0005] Benzene compounds (BTEX) are among the most abundant volatile organic compounds (VOCs). They evaporate rapidly at room temperature, are highly volatile, and exhibit high chemical reactivity, making them important precursors to ozone (O3) and secondary organic pollutants (SOA) in ambient air. Benzene, toluene, o-xylene, m-xylene, and p-xylene are the main pollutants in the BTEX series and are often used to represent the pollution characteristics of the BTEX series. Their sources are mainly related to petrochemical products and industries. Long-term exposure to BTEX in ambient air can irritate human skin and mucous membranes, and cause damage to the respiratory, hematopoietic, and nervous systems. Furthermore, BTEX poses a certain carcinogenic risk.

[0006] Currently, many macrocyclic aromatic hydrocarbons are used for the adsorption of benzene-based pollutants, but research on the adsorption of benzene-based pollutants through small molecule self-assembly is limited. Therefore, realizing compounds based on 1,10-phenanthroline and their application in the adsorption of benzene-based pollutants is of significant research value. Summary of the Invention

[0007] The purpose of this invention is to provide a small molecule compound based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid as a highly efficient adsorbent for benzene-based pollutants (benzene, toluene, o-, m-, and p-xylene). This compound can self-assemble into a typical supramolecular organic framework (SOF) material without any induction. Compared with traditional macrocyclic aromatic hydrocarbons, it has the advantages of simple synthesis and high yield. Moreover, the cavity formed by the CH⋅⋅⋅π interaction between molecules can be used to solve the technical problems of slow adsorption rate, low adsorption capacity, and deactivation due to water absorption in existing benzene-based pollutant adsorbent materials.

[0008] This invention is based on compounds constructed from 1,10-phenanthroline, with the following structural formula:

[0009] ;

[0010] The compounds of this invention, based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid, are obtained in one step via the Suzuki-Miyaura reaction. Specifically, the following steps are included:

[0011] Potassium carbonate and tetraphenylphosphine palladium were added to a mixed solution of 1,4-dioxane and water containing 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid. The reaction was carried out at 90°C under nitrogen protection for 24 hours. After the reaction was completed, the mixture was washed with distilled water and separated by column chromatography to obtain the compound.

[0012] The solvents are 1,4-dioxane and water in a ratio of 4:1 to 6:1; the molar ratio of 1,10-phenanthroline to 4-(9-carbazolyl)phenylboronic acid is 1:2 to 1:2.5; the molar amount of potassium carbonate is 1 to 1.5 times that of 1,10-phenanthroline; and the molar amount of the catalyst tetra-triphenylphosphine palladium is 0.1 to 0.2 times that of 1,10-phenanthroline.

[0013] The synthesis route is as follows:

[0014]

[0015] The small molecule compound provided by this invention exhibits high stability in the Suzuki-Miyaura reaction system using a common haloalkane as the reaction solvent and tetra-triphenylphosphine palladium as the catalyst. This compound can also self-assemble into a typical supramolecular organic framework (SOF) material without any induction, showing promising application prospects in supramolecular assembly, adsorption separation, fluorescence sensors, and functional materials.

[0016] Compared with traditional macrocyclic aromatic hydrocarbons, the present invention has simpler preparation conditions, fewer reaction steps, simpler operation, and higher yield. Due to the presence of CH⋅⋅⋅π interactions between molecules, the compound forms a three-dimensional network structure with cavities in the crystalline state, which gives the small molecule compound the same excellent properties as traditional macrocyclic aromatic hydrocarbons.

[0017] The small molecule compounds provided by this invention have a centrosymmetric structure with nanoscale electron-deficient cavities in the crystalline state, which is beneficial for adsorption and separation of molecules with similar structures, such as aromatic hydrocarbons and cyclic aliphatic compounds.

[0018] The compounds constructed from 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid provided by this invention possess the characteristic of forming non-covalent molecular channels, making them highly efficient adsorbent materials for benzene-based pollutants and showing potential application value in supramolecular assembly and adsorption separation. The compounds constructed from 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid can form non-covalent molecular channels for adsorbing and encapsulating benzene-based pollutants. Specifically, the compounds can form 1:3 host-guest compounds with benzene, meaning each host small molecule compound adsorbs 3 guest molecules; and 1:1 host-guest complexes with toluene, o-xylene, m-xylene, and p-xylene, meaning each host small molecule compound adsorbs 1 guest molecule, i.e., a cavity structure formed by two host small molecules can encapsulate two guest molecules. Attached Figure Description

[0019] Figure 1 The above is the 1H NMR spectrum of the compound constructed in this invention based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid.

[0020] Figure 2 This is the carbon NMR spectrum of the compound constructed in this invention based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid.

[0021] Figure 3 This is the mass spectrum of the compound constructed in this invention based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid.

[0022] Figure 4 The images show the single-crystal structure and molecular nanochannel crystal structure of the compound constructed based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid in this invention.

[0023] Figure 5 The eutectic structures observed from the a-axis (a), b-axis (b), and c-axis (c) are those formed by the self-assembly of compounds based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid to adsorb and encapsulate benzene in a channel.

[0024] Figure 6The eutectic structures observed from the a-axis (a), b-axis (b), and c-axis (c) are those formed by the self-assembly of compounds based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid to form a channel for adsorbing and encapsulating toluene.

[0025] Figure 7 The eutectic structures observed from the a-axis (a), b-axis (b), and c-axis (c) are those formed by the self-assembly of compounds based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid to form a channel for adsorbing and encapsulating o-xylene.

[0026] Figure 8 The eutectic structures observed from the a-axis (a), b-axis (b), and c-axis (c) are those formed by the self-assembly of compounds based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid to adsorb and encapsulate xylene in a channel.

[0027] Figure 9 The eutectic structures observed from the a-axis (a), b-axis (b), and c-axis (c) after the self-assembly of the compounds constructed based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid into a channel for adsorption and encapsulation of xylene are shown in this invention.

[0028] Figure 10 The figures show the proton NMR shifts of the main compound (a), benzene (c), and compound (b) after benzene adsorption, constructed based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid, respectively.

[0029] Figure 11 The figures show the proton NMR shifts of the main compound (a) constructed from 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid, toluene (c), and compound (b) after toluene adsorption.

[0030] Figure 12 The proton NMR shifts of the main compound (a), o-xylene (c), and compound (b) after adsorption of o-xylene are shown in the figures.

[0031] Figure 13 The proton NMR shifts of the main compound (a), m-xylene (c), and compound (b) after adsorption of m-xylene are shown for comparison.

[0032] Figure 14 The figures show the proton NMR shifts of the main compound (a) constructed from 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid, p-xylene (c), and compound (b) after adsorption of p-xylene.

[0033] Figure 15 The curves show the solid-gas adsorption of benzene series pollutant vapors on compounds over time at 293 K. Detailed Implementation

[0034] The following examples further illustrate the specific implementation methods of this product. Unless otherwise specified, all instruments and reagents used are commercially available conventional products.

[0035] Example 1

[0036] Synthesis of Compound 1 based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid

[0037] Potassium carbonate (273 mg, 1.5 mmol) and tetraphenylphosphine palladium (231 mg, 0.2 mmol) were added to a mixed solution of 1,4-dioxane and water (18 ml, 1,4-dioxane:water = 5:1, v / v) containing 1,10-phenanthroline (338 mg, 1 mmol) and 4-(9-carbazolyl)phenylboronic acid (718 mg, 2.5 mmol). The reaction was carried out at 90 °C under nitrogen protection for 24 hours. After the reaction was completed, the product was extracted with CH2Cl2 / H2O and separated by column chromatography (petroleum ether:ethyl acetate = 40:1, v / v) to give a pale yellow solid product (compound 1, 464 mg, 70%).

[0038] 1 H NMR (400 MHz, Chloroform- d ) δ 8.70 (d, J = 8.5 Hz, 4H), 8.42 (d, J =8.4 Hz, 2H), 8.26 (d, J = 8.4 Hz, 2H), 8.16 (d, J = 7.7 Hz, 4H), 7.88 (s, 2H), 7.82 (d, J = 8.5 Hz, 4H), 7.55 (d, J = 8.2 Hz, 4H), 7.48 – 7.42 (m, 4H), 7.33 –7.28 (m, 4H). ; 13 C NMR (151 MHz, Chloroform- d) δ 156.43, 149.09, 147.52,136.78, 129.32, 128.59, 127.56, 125.63, 124.82, 123.34, 123.22. ;ESI-HRMS (m / z): calcdfor C 48 H 30 N4663.2543 (M + H + ); found 663.2527 (M + H + ). ( 1 H NMR, 13 The C NMR and ESI-HRMS spectra are shown in Figures 1-3.

[0039] For single-crystal culture of compound 1 constructed from 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid, 6 mg of pure compound 1 was weighed and placed in a 10 mL glass vial. 2.5 mL of analytical grade dichloromethane was added and heated until the solution was clear and transparent. Then, 2.5 mL of analytical grade n-hexane was added to the glass vial. The cap was loosened, and single-crystal culture was carried out by allowing the solvent to evaporate slowly. The vial was placed in a cool place, and the glass vial was not shaken during observation.

[0040] The single-crystal structure of compound 1, constructed based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid, is shown below. Figure 4 The resulting cavity resembles a "bow tie." The cavity's long axis reaches 12.4 Å, and its short axis is 7.693 Å (as shown in Figure 4d). The entire single crystal exhibits centrosymmetry, but the two molecules arranged alternately are not on the same plane. Due to the C−H···π interaction between adjacent molecules, the crystal's packing structure allows it to form non-covalent molecular channels (as shown in Figure 4a), which has potential applications in supramolecular assembly and adsorption separation. Figure 5-9 This is a eutectic structure for the adsorption and encapsulation of five benzene-based pollutants by non-covalent molecular channels constructed based on 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid. It can form a 1:3 host-guest complex with benzene, with each cavity encapsulating 3 guest molecules, and can form a 1:1 host-guest complex with other benzene compounds, with each cavity encapsulating 2 guest molecules.

[0041] Figure 10-14 The 1H NMR spectrum shifts of the main molecule, benzene-based pollutants, and the main molecule after adsorption of benzene-based pollutants are compared. The peaks of benzene-based pollutants show a low-field shift in the spectrum. However, since the main molecule is in a single molecular state in the deuterated reagent, the peak shifts of benzene-based pollutants are not obvious in the spectrum.

[0042] Example 2

[0043] Adsorption of benzene series pollutants by main molecule 1

[0044] A gas-phase independent experiment was conducted to efficiently adsorb benzene-based pollutant vapors using compound 1, constructed from 1,10-phenanthroline and 4-(9-carbazolyl)phenylboronic acid. 5.00 mL open vials containing 5.00 mg of activated host molecular adsorbent were placed in 20.00 mL sealed vials containing 1.00 mL each of benzene, toluene, and o-, m-, and p-xylene. The relative absorption of the activated host molecular adsorbent for the five benzene-based pollutants was measured by the molar amount of adsorbed benzene-based pollutant vapors and by heating the crystals to release the molar amount of adsorbed vapors. Before measurement, the crystals were heated at 80 °C for half an hour to remove surface-physically adsorbed vapors. Figure 15 The graph shows the solid-gas adsorption cycle of benzene series pollutant vapors on the host molecules at 293 K over time. The crystals reach saturation point after approximately 2 hours. At the saturation point, calculations based on the experimental results show that the molar ratio of benzene adsorbed by the host molecules is 1:3, and the molar ratio of other pollutants adsorbed is 1:1, consistent with the crystal characterization results. After five cycles of reuse, the adsorption retention time of benzene series pollutants did not change significantly, indicating that the adsorbent material prepared using the compounds of this invention has a high recycling rate.

Claims

1. The application of a compound based on 1,10-phenanthroline in the adsorption of benzene-based pollutants, characterized in that, The structural formula of the compound is shown below: ； The compound forms a three-dimensional network structure with cavities in the crystalline state through intermolecular CH⋅⋅⋅π interactions; this three-dimensional network structure can self-assemble without any external induction to form non-covalent molecular channels, thereby achieving the adsorption and encapsulation of benzene-based pollutants.

2. The application of the compound based on 1,10-phenanthroline as described in claim 1 in the adsorption of benzene-based pollutants, characterized in that: The benzene-based pollutants are at least one of benzene, toluene, o-xylene, m-xylene, and p-xylene.

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