One-dimensional dysprosium polymer and preparation method thereof
Technical Field
The invention relates to a one-dimensional dysprosium polymer and a preparation method thereof, belonging to the technical field of materials.
Background
Mellitic acid (also known as 1,2,3,4,5, 6-mellitic acid or mellitic acid) contains abundant carboxyl functional groups, has strong coordination capacity, can be used as a ligand of a metal complex, particularly an actinide complex of the metal complex, and has good fluorescence performance. However, the mellitic acid salt in nature is usually present in the beeswax, is a rare organic mineral, and the price is very expensive, and the price is 900 yuan/g in the market at present, so that the use of the carboxylic acid ligand is greatly limited. In the prior art, graphite oxide and fuming nitric acid are also used for carrying out a co-thermal reaction to generate mellitic acid, but the product obtained by the method has a lot of impurities and is difficult to purify, and NO is generated2And the like, are easy to explode and pollute the air.
The prior actinide complex using mellitic acid as ligand is usually prepared by directly reacting mellitic acid with corresponding metal salt to generate a target compound, but the method has the defects of high cost, difficult purification and the like caused by obtaining mellitic acid, and has the defects of low reaction condition because the temperature is usually above 120 ℃ during direct reaction. At present, no relevant report that mellitic acid obtained by electrolyzing camphoric acid or pyridine-2, 6-dicarboxylic acid by using a graphite electrode reacts with metal salt under mild conditions to obtain a dysprosium mellitic acid complex is found.
Disclosure of Invention
The invention aims to solve the technical problem of the prior art and provides a one-dimensional dysprosium polymer with a novel structure and a preparation method thereof.
The molecular formula of the one-dimensional dysprosium polymer is as follows: [ C ]
6H
10O
11Dy·2(H
2O)]
nN is an integer and n is not less than 1; the one-dimensional dysprosium polymer belongs to a monoclinic system, P2
1The/n space group, the unit cell parameters are:
α=90.00°,β=100.397(2)°,γ=90.00°。
the repeating unit of the one-dimensional dysprosium polymer is a mononuclear dysprosium complex with the molecular formula of C6H14DyO13Molecular weight is 456.67, and the ligand is 1,2,3,4,5, 6-mellitic acid.
The invention also provides a preparation method of the one-dimensional dysprosium polymer, which comprises the following steps: dissolving dysprosium nitrate hexahydrate, camphoric acid or pyridine-2, 6-dicarboxylic acid in water, placing the obtained mixed solution in an open container, inserting an anode and a cathode, electrifying and electrolyzing, filtering the obtained material after electrolysis, collecting filtrate, reacting under heating or non-heating conditions, standing the reactant, separating out crystals, and collecting the crystals to obtain the compound; wherein, the anode and the cathode both adopt graphite electrodes.
In the preparation method, the molar ratio of the dysprosium nitrate hexahydrate to the camphoric acid or the pyridine-2, 6-dicarboxylic acid is a stoichiometric ratio, specifically 2: 1. in actual practice, dysprosium nitrate hexahydrate may be in relative excess.
In the above preparation method, the amount of water is preferably such that most of the camphoric acid is dissolved but slightly precipitated. Specifically, the amount of water used for the whole raw materials participating in the reaction is usually 15 to 20mL based on 0.5mmol of camphoric acid or pyridine-2, 6-dicarboxylic acid. In the specific dissolving step, dysprosium nitrate hexahydrate and camphorate or pyridine-2, 6-dicarboxylic acid are mixed and then dissolved in distilled water, or the dysprosium nitrate hexahydrate can be added after the camphorate or the pyridine-2, 6-dicarboxylic acid is dissolved in water and stirred for a plurality of minutes.
In the preparation method, the graphite electrode is a commercial electrode, and further processing is not needed before use. The power supply for electrolysis is a direct current power supply, and is usually between 5 and 20V. The period of the electrolysis is preferably at least 5 hours or more, and it is preferable to stop the electrolysis when there is a substance falling off from the graphite electrode as the anode during the electrolysis, and the period of time required for this is generally 18 to 24 hours.
In the above production method, the time required for obtaining the target product when the reaction is carried out without heating is longer than that under heating, and it usually takes 7 to 15 days. When the reaction is carried out under heating conditions, it is preferable to control the reaction at a temperature of 80 ℃ or less, preferably 50 to 65 ℃, and the time of the reaction under the preferable conditions is usually controlled to 18 to 24 hours.
Compared with the prior art, the one-dimensional dysprosium polymer with a novel structure is obtained in a mild environment (the reaction temperature is less than or equal to 80 ℃) by taking the cheap camphoric acid or the pyridine-2, 6-dicarboxylic acid as the raw material, and compared with the prior method of directly taking the mellitic acid as the ligand and synthesizing the dysprosium complex at the temperature of more than 120 ℃, the preparation method is simple, easy to control, safe, mild in reaction condition, low in cost and good in repeatability.
Drawings
FIG. 1 shows [ C ] obtained in example 1 of the present invention6H10O11Dy·2(H2O)]nThe metal coordination environment diagram of (1);
FIG. 2 shows [ C ] obtained in example 1 of the present invention6H10O11Dy·2(H2O)]nThe ligand coordination environment diagram of (1);
FIG. 3 shows [ C ] obtained in example 1 of the present invention6H10O11Dy·2(H2O)]nA one-dimensional structure diagram.
Detailed Description
The present invention will be better understood from the following detailed description of specific examples, which should not be construed as limiting the scope of the present invention.
Example 1
Mixing 100mg (0.5mmol) camphoric acid and 457mg (1mmol) Dy (NO)3)3·6H2Adding O into a 50mL beaker, adding 20mL of distilled water, stirring at normal temperature for 10min, stopping stirring, inserting two graphite electrodes (one is used as an anode and the other is used as a cathode), electrifying for 24h under 12V direct current voltage (at the moment, the graphite electrode as the anode is observed to have substance falling off), stopping electrifying, filtering out impurities such as graphite slag and the like, collecting filtrate, filling into a 20mL sample bottle, covering the sample bottle with a cover, putting the sample bottle into a 60 ℃ oven for reaction for 24h, taking out, standing and cooling, separating out colorless transparent strip crystals at the bottom of the sample bottle, collecting the crystals, and drying. The yield was 8.9% (based on dysprosium nitrate hexahydrate). Elemental analysis (%) (C)6H14DyO13) The experimental values are C, 15.61, H, 3.10; theoretical values of C,15.78, H, 3.09.
Selecting the crystals with proper size obtained in the embodiment, placing the crystals on a Supernova single crystal diffractometer of Agilent company, and carrying out monochromatization by using graphite
And (4) performing single crystal test by using rays. Under the condition of 295K, the method comprises

The diffraction points are collected in a scanning mode within the range of more than or equal to 2.9 degrees and less than or equal to 25.0 degrees. The initial crystal structures of the products obtained in the embodiment are solved by adopting a SHELXS-97 and Olex-2 direct method, the geometric hydrogenation is carried out, and the non-hydrogen atom coordinates and the anisotropic thermal parameters are refined by adopting a SHELXL-97 full matrix least square method. The obtained crystallographic data are shown in the following table 1, partial bond length and bond angle data are shown in the following table 2, and the one-dimensional polymerization diagram of the obtained colorless strip crystal is shown in fig. 3, wherein fig. 1 is a metal coordination environment diagram of the obtained colorless strip crystal, and fig. 2 is a ligand coordination environment diagram of the obtained colorless strip crystal. Therefore, it was confirmed that the crystal obtained in this example was a one-dimensional dysprosium polymer [ C ]
6H
10O
11Dy·2(H
2O)]
nThe repeating unit of the polymer is a mononuclear dysprosium complex with a molecular formula of C
6H
14DyO
13Molecular weight is 456.67, and the ligand is 1,2,3,4,5, 6-mellitic acid.
Table 1: [ C ]6H10O11Dy·2(H2O)]nCrystallographic data of
Table 2: [ C ]
6H
10 O
11Dy·2(H
2O)]
nPartial bond length of
Key angle (degree) table
Comparative example 1
Example 1 was repeated except that water was changed to a single solvent such as methanol, acetonitrile, dichloromethane, chloroform, DMF or DMSO, or water and the above single solvent were changed in a ratio of 1: 1, and the volume ratio of the mixed solvent to the mixed solvent. As a result, no crystalline or other shaped (e.g., powdery) product is formed.
Comparative example 2
Example 1 was repeated except that dysprosium acetate tetrahydrate, dysprosium perchlorate hexahydrate or dysprosium chloride hexahydrate was used in place of dysprosium nitrate hexahydrate, and an acetic acid molecule (or CH) was desired3COO-) Perchlorate (or ClO)4 -) Or Cl-The ions can replace water molecules participating in coordination, or a complex with a new structure is obtained through bridging of acetate or perchlorate, but no crystal is obtained, which indicates that the thermodynamic conditions for forming dysprosium polymer and crystallizing cannot be achieved by using other dysprosium salts.
Example 2
Example 1 was repeated except that pyridine-2, 6-dicarboxylic acid was used instead of camphoric acid.
As a result, colorless transparent crystals in the form of stripes were obtained. The yield was 8.3% (based on dysprosium nitrate hexahydrate).
The product obtained in the example is analyzed by single crystal diffraction, and the obtained colorless transparent strip crystal is determined to be a one-dimensional dysprosium polymer [ C ]6H10O11Dy·2(H2O)]n。
Example 3
Example 1 was repeated except that the collected filtrate was reacted at room temperature for 7 days.
As a result, colorless transparent crystals in the form of stripes were obtained. The yield was 7.2% (based on dysprosium nitrate hexahydrate).
The product obtained in the example is analyzed by single crystal diffraction, and the obtained colorless transparent strip crystal is determined to be a one-dimensional dysprosium polymer [ C ]6H10O11Dy·2(H2O)]n。
Example 4
Example 1 was repeated, except that the reaction temperature was changed to 50 ℃.
As a result, colorless transparent crystals in the form of stripes were obtained. The yield was 6.6% (based on dysprosium nitrate hexahydrate).
The product obtained in this example was subjected to single crystal diffractionAnalyzing and determining the obtained colorless transparent strip crystal as one-dimensional dysprosium polymer [ C ]6H10O11Dy·2(H2O)]n。