Chelatings (inner chelates)

NetworkSection IV chelates (inner complexes) I, the concept of chelates chelates, also known as endosomes, are chelate formers (central ions) and certain chelating agents (liants) that meet certain conditions to form a combination of ring structure. "Chelation" means ring, as if the crab's two chelating bodies (central ions) clamped together, so called chelate.condition for the formation of chelates is that the chelating agent must have two or more mating atoms (mainly N, O, S, etc.) that can give electron pairs. The second condition is that each of the two mating atoms that can give an electron pair must be separated by two or three other atoms, because only then can a stable ring of five or six atoms be formed. For example, in amino acetic acid ions (H2N-CH2-COO-), the electron's hydroxyoxygen and amino nitrogen are separated by two carbon atoms, so it can form a stable
compound with a five-
.rings are not common in chelates, and there are fewer rings above six atoms. The central ion has a certain number of charges, but also a certain number of allocations. Cu (II.) has two positive charges, and its ration is 4. Amino acetic acid ions (H2N-CH2-COO-) have both amino nitrogen, which can give electron pairs; amino nitrogen can meet the number of central ions, hydroxyoxygen can satisfy both the number of distributions and the number of charges, so Cu 2 plus and two (H2N-CH2-COO-After chelation, it is obtained that the neutral molecule ddi amino acetate copper (II.) (referred to as amino acetate) (Cu (H2N-CH2-COO)2) because hydroxyoxy has a negative charge, so its bond formed with Cu 2 plus is usually expressed as "-".stability of the chelate is one of the characteristics brought to them by the ring structure. The more rings there are, the more stable the chelate becomes. Commonly referred to as the "chelation reaction" refers to the special stability of the compound due to chelation.the special stability of the chelate, it is rare to reflect the properties of metal ions before they are chelating. After the metal ions form chelate, great changes have taken place in the properties of color, redox stability, solubility and crystal. Many metal chelates have characteristic colors, and they can be dissolved in
organic
solvents. Using these characteristics, the analysis and separation of precipitation, solvent extraction and separation, color ratio quantification and so on can be carried out.II, chelating agentcommonly used chelating agent is ammonia chelating agent, is a similar to aminodiacetic acid (CH2COOH)2) as the base of the chelating agent, it is N, O as the chelating atom, and metal ions chelate when forming a ring-like The commonly used ammonia chelates for chelatesare:ammonia chelate I. (ATA) refers to ammonia triacetic acid, and its structure is:acetaminophen chelate II. (
EDTA
) refers to acetylacetic acid. Its structure is:acetylene tetacetic acid is a four-binary acid, if Y is used to represent its acid root, then ethyl diamine tetacetic acid can be short as H4Y.because the solubility of ethyldamine tetacetic acid in water is relatively small, while the solubility of secondary sodium salts in water is relatively large. EDTA nitrate salts are often used in practical applications. EDTA nitrate contains 2 molecule crystalline water, its structure is:EDTA nitrate salt is sometimes called EDTAIII. But it's still customary to call it EDTA. It is represented by a simplified Na2H2Y and 2H2O.EDTA is a four-way acid that is dissophed in water step by step:With the exception of alkali metal ions, EDTA forms a stable metal chelate with almost all metal ions. Moreover, in general, regardless of the price of metal ions, 1 metal ion can form a soluble stable chelate with 1 EDTA acid root (Y4-). For example: M represents metal ions, and numbers and symbols in the upper right corner represent the ion price of ions. although most metal ions can form chelates with EDTA, except for alkali metal ions, their stability varies greatly. EDTA is the most widely used ammonia chelate, with EDTA standard liquid can be titration of dozens of metal ions, this method is called EDTA titration. At present, the so-called chelating titration method mainly refers to EDTA titration. third, the medical application of chelates chelates exist in nature is relatively widespread, and has an important role in the phenomenon of life. Hemolyxin, for example, is an iron-containing chelate that acts as an oxygen delivery agent in the human body. vitamin
B12 is a cobalt-containing chelate that has a prevention and treatment effect on malignant anemia. Insulin is a zinc-containing chelate that plays an important role in regulating the metabolism of substances in the body, especially sugars. Some chelating agents can be used as antidotes to poisoning of heavy metals (Pb2 plus, Pt2 plus, Cd2 plus, Hg2 plus). Such as propylene alcohol or EDTA dodium salts, such as treatable metal poisoning. Because they form stable chelates with toxic metal ions, water-soluble chelates can be excreted from the kidneys. drugs themselves are chelates. For example, some metal ions used to treat diseases, because of their toxicity, irritation, difficult to absorb, etc. are not suitable for clinical applications, they can be turned into chelates can reduce their toxicity and irritation, to help absorb. chelates
also
in bio-chemical testing, drug analysis, environmental monitoring, etc.