Complexes with chelating agents

Degradation of Tetracyclines Tetracyclines are relatively stable under acidic conditions but not under alkaline conditions. They form complexes with chelating agents such as divalent metals, proteins, and silanol groups (Oka et al., 2000 ... 

A complete removal of oxygen in aqueous solution is not feasible and thus in practice, the metal ions are frequently complexed with chelating agents (EDTA, disodium edate, citric acid, etc.). 

Other factors also affect the mobility of uranium in soil. A field study performed near an active carbonate leach uranium mill showed that uranium in an alkali matrix can migrate to the groundwater (Dreesen et al. 1982). Uranium mobility may also be increased due to the formation of soluble complexes with chelating agents produced by microorganisms in the soil (Premuzie et al. 1995). 

To summarize, two of the zinc atoms of LADH appear to be located at the active site of the enzyme they exchange readily in acetate buffer and are either removed by or form mixed complexes with chelating agents, resulting in a loss of catalytic activity. An additional 1.5 to 2.0 gram atoms of zinc seem to be buried in the molecule elsewhere than at the active site they do not exchange with isotopic zinc in acetate, but... 

In Table 20.1 are listed most of the actinyl compounds whose structures have been determined by analysis with single-crystal data or have been shown by powder diffraction to be isostructural with one of the known structures. Reviews have been written about uranyl complexes with chelating agents [69,70] and with carboxylic adds [71]. 

Platinum-group metals (qv) form complexes with chelating polymers with various 8-mercaptoquinoline [491-33-8] derivatives (83) (see Chelating agents). Hydroxy-substituted quinolines have been incorporated in phenol—formaldehyde resins (84). Stannic chloride catalyzes the condensation of bis(chloromethyl)benzene with quinoline (85). 

The methods which involve complexation of the metal ion with chelating agents followed by adsorption on a solid phase such as octadecylsilane (ODS) [2], Zeolite [3] or activated cai bons [4] have been reported. 

Thennodynamic inhibitors are complexing and chelating agents, suitable for specific scales. For example, for scale inhibition of barium sulfate, common chemicals are ethylenediaminetetraacetic acid (EDTA) andnitrilotriacetic acid. The solubility of calcium carbonate can be influenced by varying the pH or the partial pressure of carbon dioxide (CO2). The solubility increases with decreasing pH and increasing partial pressure of CO2, and it decreases with temperature. 

As well as the above 2,3-dimercaptoalkanes a few other vicinal dithiols have also been sythesized. The interaction of methylmercury(II) with chelating agents such as BAL involves linear two-coordinate complexes and in only a few cases has chelation involved a bidentate ligand. In a search for evidence of thiol-containing bidentate chelation, Alcock et al.311 synthesized three sterically constrained dithiols - cyclohexane-1,2-dithiol, toluene-3,4-dithiol and bicyclo[2.2. l]heptane-2,3-dithiol - and demonstrated by spectroscopy and crystallography their formation of chelates with methylmercury(II) of the form (40). 

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