Preparation of complexes of 5-bromopyridine-2,3-dicarboxylic acid_Industrial additives

Preparation background and overview of 5-bromopyridine-2,3-dicarboxylic acid complexes

5-Bromopyridine-2,3-dicarboxylic acid is an organic intermediate that can be used to prepare nickel complexes. 5-Bromopyridine-2,3-dicarboxylic acid is a nitrogen heterocyclic polycarboxylic acid compound and is a commonly used ligand. On the one hand, nitrogen atoms and oxygen atoms can easily coordinate with transition metal ions to form stable coordination bonds. It is easy to obtain diverse topological structures and has excellent performance; on the other hand, partially or completely deprotonated carboxyl groups can act as both hydrogen bond donors and hydrogen bond acceptors, and can easily form structures of different dimensions. In addition, nitrogen-heterocyclic polycarboxylic acid compounds have good fluorescent properties due to their structure having conjugated double bonds and aromatic groups.

Metal-Organic Frameworks (MOFs) are coordination polymers constructed of inorganic metals and organic ligands, which change the relationship between metal ions, organic ligands, or metal ions and organic ligands. The acting force can produce MOFs materials with variable properties and structures. There are various methods for preparing MOFs materials. Commonly used methods include volatilization method, diffusion method, hydrothermal/solvothermal method, ultrasonic method, microwave method, etc. MOFs based on transition metals and polycarboxylate ligands have received widespread attention due to their huge potential application value. Metal ions and ligands can self-assemble through hydrogen bonds or π-π interactions to form various topological structures. or supramolecular structure.

Preparation of complexes of 5-bromopyridine-2,3-dicarboxylic acid Preparation of complexes

Preparation report of 5-bromopyridine-2,3-dicarboxylic acid complex 1.

CN201811070742.6 reports a 5-bromopyridine-2,3-dicarboxylic acid nickel complex and its preparation method. The idea of ​​the present invention is to use 5-bromopyridine-2,3-dicarboxylic acid as a ligand and nickel chloride hexahydrate to obtain a 5-bromopyridine-2,3-dicarboxylic acid nickel complex through a solvothermal method. The 5-bromopyridine-2,3-dicarboxylate nickel complex of the present invention belongs to the monoclinic crystal system, the space group is P2/c, and the unit cell parameters are α=90.00°, β=105.242°, and γ=90.00°. Z=4. The specific steps for preparing the 5-bromopyridine-2,3-dicarboxylic acid nickel complex are:

(1) Weigh 0.25mmol (0.0595g) NiCl·6HO and dissolve it in 5mL distilled water and 5mL absolute ethanol to prepare a nickel chloride solution.

(2) Weigh 0.25mmol (0.0615g) of 5-bromopyridine-2,3-dicarboxylic acid and 2mLDMF, add it to a 25mL beaker, stir until dissolved, and prepare 5-bromopyridine-2. 3-Dicarboxylic acid solution.

(3) Add the nickel chloride solution prepared in step (1) dropwise to the 5-bromopyridine-2,3-dicarboxylic acid solution prepared in step (2), shake with ultrasonic for 20 minutes, and add ammonia solution Adjust the pH value to 5-7 to make the solution clear, and then continue shaking for 10 minutes to prepare a mixed solution.

(4) Transfer the mixed solution prepared in step (3) into a 25 mL reaction kettle with a polytetrafluoroethylene bottle, place it in an oven and heat it to 140°C for 72 hours, then cool down at a rate of 10°C/h. to 90°C, and then keep it for 10 hours. Turn off the oven and let it cool to room temperature naturally. Then take out the reaction kettle. Green needle-like crystals will appear. Wash them 3 times with acetone and absolute ethanol alternately. Each time, acetone and absolute ethanol are used. The dosage is 5 mL, and then placed in a 50°C vacuum drying oven and dried for 12 hours to prepare 5-bromopyridine-2,3-dicarboxylic acid nickel complex.

The preparation method of the present invention has the advantages of green environmental protection, simple operation, good repeatability, etc., and successfully synthesizes 5-bromopyridine-2,3-dicarboxylic acid nickel complex, which is a transition for the synthesis of nitrogen-containing heterocyclic carboxylic acids. Metal complexes provide a certain theoretical basis.

Preparation report of 5-bromopyridine-2,3-dicarboxylic acid complex 2.

CN202011 Methyltetrahydrofuran 174446.8 provides the structure, properties and preparation method of a nickel complex composed of 5-bromopyridine-2,3-dicarboxylic acid and 1,10-phenanthroline. Using 5-bromopyridine-2,3-dicarboxylic acid (5-Br-2,3-pydc) as the main ligand, 1,10-phenanthroline (1,10-phen) as the auxiliary ligand, and sulfuric acid Nickel is the source of nickel through the nickel complex. Structural characteristics of this nickel complex: chemical formula [Ni(5-Br-2,3-pydc)(1,10-phen)2·9H2O]n(5-Br-2,3-pydc=5-bromopyridine-2 ,3-dicarboxylic acid; 1,10-phen=1,10-phenanthroline), belongs to the triclinic crystal system, the space group is P21/c, the unit cell parameters are α=101.939°, β=92.843°, γ=116.506°, Z=2. The basic unit of this complex consists of 1 Ni(Ⅱ) central ion, 1 main ligand 5-bromopyridine-2,3-dicarboxylic acid anion, and 2 auxiliary ligands ( 1,10-phen) and 9 guest water molecules. Each Ni(II) ion is coordinated with 1 carboxyl oxygen atom and 1 nitrogen atom of the ligand 5-bromopyridine-2,3-dicarboxylic acid, and 4 nitrogen atoms of 1,10-phenanthroline , forming a six-coordinate structure. The coordination bond Ni-O bond length is between, and the Ni-N bond length is at the bond angle O-Ni-X (X=O, N) between 79.34(10)~168.64(10)°.

References

[1] [Chinese invention] CN202011174446.8 A nickel complex composed of 5-bromopyridine-2,3-dicarboxylic acid and 1,10-phenanthroline and its preparation method

[2] [Chinese invention] CN201811070742.6 5-bromopyridine-2,3-dicarboxylic acid nickel complex and preparation method thereof