CN103254136B - Method for preparing quadri [4-(1- imidazolyl) phenyl] methane - Google Patents

Abstract

The invention discloses a method for preparing tetrakis[4-(1-imidazolyl)phenyl]methane; specifically, mixing tetrakis(4-bromophenyl)methane, cuprous iodide, potassium carbonate and imidazole evenly, and placing In a container, the crude product 1 is obtained after heating and reacting; then water, ethylenediaminetetraacetic acid and ammonia water are added to the crude product 1, soaked for 4 to 6 hours, filtered, and washed to obtain the crude product 2; the crude product 2 is After recrystallization, light yellow crystals are obtained, namely the tetrakis[4-(1-imidazolyl)phenyl]methane. The product obtained by this method has excellent fluorescence properties and can be used to prepare fluorescent materials. The method disclosed by the invention has low cost, mild reaction conditions, short reaction time, simple post-treatment of the reaction, is beneficial to product purification and high product yield, and compared with the prior art, the use of a reaction solvent is avoided, and the preparation process Environmentally friendly and easy to operate industrially.

Description

A kind of method for preparing tetrakis [4-(1-imidazolyl) phenyl] methane

technical field

The invention relates to the preparation of organic ligands containing imidazole groups, in particular to a preparation method of tetrakis[4-(1-imidazolyl)phenyl]methane.

Background technique

Coordination polymers containing imidazole-based ligands have unique optical properties, magnetism, catalysis, and biological activity, and have the characteristics of complexes and polymers. They have broad applications in new materials, molecular recognition, and supramolecular self-assembly. application prospects.

The organic ligands containing multiple imidazole groups are polydentate imidazole ligands, which have the characteristics of many coordination sites, strong coordination ability, and rich coordination modes. Because the imidazole group has good fluorescence, ultraviolet and other characteristics, and the coordination polymer formed by the multidentate imidazole ligand and metal ion has good magnetic properties, adsorption and other properties, so the synthesis of new multidentate imidazole ligand and the use of These polydentate imidazole ligand-assembled clusters and coordination polymers have attracted extensive attention of researchers.

In the prior art, there are many reports on ligands containing two or three imidazole groups, and some compounds have been successfully commercialized; however, few studies involve ligands containing four imidazole groups.

Seung Uk Son's research group disclosed a method for preparing tetrakis[4-(1-imidazolyl)phenyl]methane, see: Jaewon Choi, Hye Yun Yang, Dr. Hae Jin Kim, Prof. Seung Uk Son Angew. Chem . Int. Ed. 2010 49:7718-7722, which is prepared by the classic monovalent copper-catalyzed Ullmann coupling reaction. However, the above scheme uses the traditional solution method, the reaction time is long, and it needs to be refluxed for 2 days; at the same time, the reaction process uses toxic organic solvents such as dimethyl sulfoxide and dichloromethane, which is harmful to the environment and the post-treatment is complicated, which is not conducive to industrial production. .

Therefore, it is necessary to find a method with simple source of raw materials, high product yield, simple operation, safety and environmental protection to effectively synthesize tetrakis [4-(1-imidazolyl)phenyl]methane.

Contents of the invention

The object of the present invention is to provide a method for preparing tetrakis[4-(1-imidazolyl)phenyl]methane with less environmental pollution, short reaction time and convenient product separation.

In order to achieve the above-mentioned purpose of the invention, the technical scheme adopted in the present invention is:

A method for preparing tetrakis [4- (1-imidazolyl) phenyl] methane, comprising the following steps:

(1) Mix tetrakis(4-bromophenyl)methane, cuprous iodide, potassium carbonate and imidazole evenly, place them in a container, and obtain crude product 1 after heating and reacting; tetrakis(4-bromophenyl)methane, iodine The mol ratio of cuprous chloride, potassium carbonate and imidazole is 1: 0.4: 6: 8～10;

(2) Add water, ethylenediaminetetraacetic acid and ammonia water with a concentration of 25-28% to the above crude product 1, soak for 4-6 hours, filter and wash to obtain crude product 2; among them, ethylenediaminetetraacetic acid and The molar ratio of cuprous iodide is 1:0.5~1; the molar ratio of ethylenediaminetetraacetic acid and ammonia water is 1:4~6;

(3) The above crude product 2 was recrystallized to obtain light yellow crystals, namely the tetrakis[4-(1-imidazolyl)phenyl]methane.

In the preferred technical solution, the heating method in the step (1) is microwave heating; the microwave heating time is 90 seconds, and the power is 720w.

The preferred technical scheme, according to the molar ratio, tetrakis (4-bromophenyl) methane: cuprous iodide: potassium carbonate: imidazole=1: 0.4: 6: 10.

In the above technical scheme, the reagent used for the recrystallization of the crude product 2 in step (3) is a methanol/water mixture; according to the volume ratio, methanol:water=1:4.

The present invention uses a solvent-free solid-phase reaction method to prepare the target product. Before the heating reaction, various raw materials need to be mixed evenly. The method adopted is not limited and belongs to the prior art. In the crucible, grind it into powder and mix it evenly.

In the present invention, the crude product 1 contains impurities such as copper ions, imidazole, and potassium carbonate. After adding water, ethylenediaminetetraacetic acid, and ammonia water to the crude product 1, the copper ions are dissolved in water in the form of a complex, and the imidazole and carbonic acid Potassium is also soluble in water, and tetrakis [4-(1-imidazolyl) phenyl] methane is separated out in the form of precipitation, and after filtration, crude product 2 is obtained, and crude product 2 is recrystallized with methanol/water mixture, thereby The pure organic tetrakis[4-(1-imidazolyl)phenyl]methane is obtained, and the whole process of purification and post-treatment is simple.

Above-mentioned technical scheme can be expressed as follows:

Owing to above-mentioned technical scheme uses, the present invention has following advantage compared with prior art:

1. The present invention prepares tetrakis[4-(1-imidazolyl)phenyl]methane by a solvent-free solid-phase reaction under microwave heating conditions, since no reaction solvent is needed, it is more convenient than using dimethyl sulfoxide in the prior art Green;

2. The method disclosed by the invention has the advantages of low cost, mild reaction conditions, short reaction time, simple reaction post-treatment, favorable product purification, high product yield, and easy industrial operation;

3. The product obtained by the invention has excellent fluorescent properties, and is a ligand that can be used to prepare fluorescent materials. After being excited by 327nm light, it can generate a strong emission peak at 400nm.

Description of drawings

Fig. 1 is the LC-MS liquid chromatogram of tetrakis [4-(1-imidazolyl) phenyl] methane in embodiment one;

Fig. 2 is the LC-MS mass spectrogram of tetrakis [4- (1-imidazolyl) phenyl] methane in embodiment one;

Fig. 3 is the proton nuclear magnetic spectrum of four [4-(1-imidazolyl) phenyl] methane in embodiment one;

Fig. 4 is the carbon NMR spectrum of four [4-(1-imidazolyl) phenyl] methane in embodiment one;

Fig. 5 is the fluorescence emission spectrum of tetrakis [4-(1-imidazolyl) phenyl] methane in embodiment one;

Fig. 6 is the crystal structure figure of imidazole-based coordination polymer in embodiment three;

Fig. 7 is the fluorescence emission spectrum of the imidazole-based coordination polymer in Example 3.

Detailed ways

The present invention will be further described below in conjunction with embodiment:

Embodiment one: the synthesis of tetrakis [4- (1-imidazolyl) phenyl] methane

Specific steps are as follows:

Add 0.636g (1mmol) of tetrakis(4-bromophenyl)methane, 0.076g (0.4mmol) of cuprous iodide, 0.828g (6mmol) of potassium carbonate and 0.68g (10mmol) of imidazole into the crucible, grind it with a glass rod Put it into an ordinary household microwave oven after mixing it evenly, and heat it in a microwave for 90 seconds with a power of 720w. It is detected by TLC (thin layer chromatography) method, and it is found that the point of the raw material tetrakis (4-bromophenyl) methane disappears, and the reaction is complete. Crude product 1;

Add 10mL of water, 0.117g (0.4mmol) of ethylenediaminetetraacetic acid (0.4mmol) and 0.15mL of 25% ammonia water to the crude product 1, soak for 5 hours, filter, and wash the precipitate with water 3 times (10mL/time) to obtain the crude product 2;

The crude product 2 was recrystallized with 20 mL of methanol/water (volume ratio 1:4) to obtain light yellow crystals, namely the product tetrakis[4-(1-imidazolyl)phenyl]methane, with a mass of 0.528 g (total yield 90% ), the product was subjected to LC-MS, infrared, NMR, fluorescence test, and elemental analysis.

Accompanying drawing 1 is the LC-MS (liquid chromatography-mass spectrometry) liquid chromatogram of above-mentioned tetrakis [4-(1-imidazolyl) phenyl] methane, and accompanying drawing 2 is tetrakis[4-(1-imidazolyl) ) phenyl] methane LC-MS (liquid chromatography-mass spectrometry) mass spectrogram, accompanying drawing 3 is the proton magnetic spectrum of tetrakis [4-(1-imidazolyl) phenyl] methane, accompanying drawing 4 is four [ The carbon nuclear magnetic spectrum of 4-(1-imidazolyl) phenyl] methane, the result of analyzing accompanying drawing 1, accompanying drawing 2, accompanying drawing 3 and accompanying drawing 4 is: LC-MS: 585.3, 293.2, 195.9; ¹ HNMR ( 300 MHz, CDCl ₃ , 298 K, TMS): δ = 7.87 (s, 4H, Imz–H), 7.38 (s, 16H, Ph-H), 7.29 (s, 4H, Ph-H), 7.21 (s , 4H, Ph-H); ¹³ CNMR (300 MHz, CDCl ₃ , 298 K): δ= 144.7, 135.8, 135.4, 132.1, 130.7, 120.8, 117.9, 63.7 ppm.

IR: v(KBr)/cm ^-1 3410m, 3111m, 1606m, 1517s, 1423w, 1305s, 1245w, 1192w, 1108m, 1057s, 963m, 818s, 737m, 658m, 559m; elemental analysis (%): C,75.96; H, 4.82; N, 19.22.

Theoretical for tetrakis[4-(1-imidazolyl)phenyl]methane: ¹ H NMR (300 MHz, CDCl ₃ ): δ = 7.90 (s, 4H, Imz–H), 7.39 (s, 16 H, Ph -H), 7.31 (s, 4H, Imz–H), 7.21 (s, 4H, Imz–H) ¹³ C NMR (75 MHz, CDCl ₃ ): δ = 145.3, 135.8, 135.4, 132.2, 131.0, 120.9, 118.0, 63.7 ppm; Elemental analysis (%): C, 76.01; H, 4.83; N, 19.17. Through analysis, the product prepared by the present invention is consistent with the theory.

Accompanying drawing 5 is the fluorescence emission spectrum of tetrakis [4-(1-imidazolyl) phenyl] methane prepared by the present invention, referring to accompanying drawing 5, after product is excited by the light of 327nm, there is stronger emission peak at 400nm place, It shows that it has excellent fluorescent properties and is a ligand that can be used to prepare fluorescent materials.

Embodiment two: four [4- (1-imidazolyl) phenyl] the synthesis of methane

Specific steps are as follows:

Add 0.636g (1mmol) of tetrakis(4-bromophenyl)methane, 0.076g (0.4mmol) of cuprous iodide, 0.828g (6mmol) of potassium carbonate and 0.544g (8mmol) of imidazole into the crucible, grind it with a glass rod Put it into an ordinary household microwave oven after mixing it evenly, and heat it in a microwave for 90 seconds with a power of 720w. It is detected by TLC (thin layer chromatography) method, and it is found that the point of the raw material tetrakis (4-bromophenyl) methane disappears, and the reaction is complete. Crude product 1;

Add 10mL of water, 0.117g (0.4mmol) of ethylenediaminetetraacetic acid (0.4mmol) and 0.15mL of 28% ammonia water to the crude product 1, soak for 6 hours, filter, and wash the precipitate with water 3 times (10mL/time) to obtain the crude product 2;

The crude product 2 was recrystallized with 20mL of methanol/water (volume ratio 1:4) to obtain light yellow crystals, the product tetrakis [4-(1-imidazolyl)phenyl]methane, mass 0.496g (total yield 85% ).

Example 3: Synthesis of imidazole-based coordination polymers

Take zinc nitrate hexahydrate Zn(NO ₃ ) ₂ 6H ₂ O (0.15g, 0.5mmol), isophthalic acid (0.13g, 0.5mmol) and tetrakis[4-(1-imidazolyl)phenyl]methane ( 0.14g, 0.25mmol) into an 8mL heat-resistant glass tube, add 3mL of acetonitrile/water mixed solvent with a mass ratio of 1:1 and seal it. React in an oven at a constant temperature of 150°C for 2 days, then slowly cool down to room temperature at a rate of 5°C/hour to obtain a yellow crystal, which is the product imidazole-based coordination polymer, with a molecular formula of C ₅₃ H ₃ N ₈ O ₈ Zn ₂ . Product is carried out infrared analysis, and result is as follows:

IR:v(KBr)/cm ^-1 3447m, 3136w, 1613s, 1561w, 1523s, 1373s, 1313w, 1270w, 1126w, 1068m, 966m, 827m, 762s, 656m, 561m.

Accompanying drawing 6 is the crystal structure figure of above-mentioned imidazolyl coordination polymer, as can be seen from accompanying drawing 6, the polymer obtained is a single crystal structure; And utilized X-ray single crystal diffraction to analyze its structure, the results are shown in Table 1 , the single crystal structure of the product was further confirmed by Table 1.

Accompanying drawing 7 is the fluorescence emission spectrum of above-mentioned imidazolyl coordination polymer, referring to accompanying drawing 7, the polymer is excited by the light of wavelength 284nm, and the fluorescence emission peak appears at 325nm, compared with ligand, obvious blue shift has taken place, It is a new coordination polymer with fluorescent properties.

Table 1 Crystallographic parameters of imidazole-based coordination polymers

Claims (4)

1. A method for preparing four [4-(1-imidazolyl) phenyl] methane, is characterized in that, comprises the following steps: (1) Mix tetrakis(4-bromophenyl)methane, cuprous iodide, potassium carbonate and imidazole evenly, place them in a container, and heat and react to obtain the crude product tetrakis[4-(1-imidazolyl)phenyl] Methane; the mol ratio of the tetrakis (4-bromophenyl) methane, cuprous iodide, potassium carbonate and imidazole is 1: 0.4: 6: 8～10; (2) Add water, ethylenediaminetetraacetic acid and ammonia water with a concentration of 25-28% to the crude product tetrakis [4-(1-imidazolyl)phenyl]methane in step (1), soak for 4-6 hours, Filter, wash, and dry to obtain the crude product tetrakis[4-(1-imidazolyl)phenyl]methane; wherein, the molar ratio of ethylenediaminetetraacetic acid to cuprous iodide is 1:0.5～1; The mol ratio of acetic acid and ammoniacal liquor is 1: 4～6; (3) The crude product tetrakis[4-(1-imidazolyl)phenyl]methane in step (2) was recrystallized to obtain light yellow crystals, i.e. tetrakis[4-(1-imidazolyl)phenyl]methane; The heating method in the step (1) is microwave heating; the microwave heating time is 90 seconds, and the power is 720w. 2. prepare the method for tetrakis [4-(1-imidazolyl) phenyl] methane according to claim 1, it is characterized in that: according to mol ratio, tetrakis (4-bromophenyl) methane: cuprous iodide: carbonic acid Potassium:imidazole=1:0.4:6:10. 3. the method for preparing tetrakis [4-(1-imidazolyl) phenyl] methane according to claim 1, is characterized in that: the crude product tetrakis [4- for step (2) in described step (3) The reagent for recrystallization of (1-imidazolyl)phenyl]methane is methanol/water mixture. 4. the method for preparing tetrakis [4-(1-imidazolyl) phenyl] methane according to claim 3, is characterized in that: according to volume ratio, methyl alcohol: water=1: 4.