Properties of chelates

Biological significance can sometimes arise in rather unexpected ways the thermal properties of chelate polymers of 2,6-diaminopimelic acid (dap 12) and 4,4 -diamino-3,3 -dicarboxybiphenyl (bbdc 13) with Zn11 have been compared241 with those of non-polymeric divalent metal chelates with amino acids. This confirms the expected enhancement of thermal stability when coordination polymerization occurs, these results possibly being relevant to the thermal stability of certain bacterial spores which contain dap. Zn11 complexes of dap are more thermally stable than those of bbdc, possibly because the latter chelate cannot pack as well, due to the intermolecular repulsions of the biphenyl groups. 

Boreskov, G. K., Keier, N. P., Rubtsova, L. P., Rukhadze, E. G. The Catalytic Properties of Chelate (Intramolecular) Polymers. Dokl. SSSR. Phys. Chem. Section 144,... 

Casella L, Monzani E, Fantucci P et al (1996) Axial imidazole distortion effects on the catalytic and binding properties of chelated deuterohemin complexes. Inorg Chem 35 439 144... 

Mercapto-2-substituted quinolines, structure and properties of chelates 90MI37. 

The synthesis and properties of chelate resins containing l,2,3-triazole-4,5-dicarboxylic acid as an anchor group have been described. The 2-vinyltriazole (431) was copolymerized with divinylbenzene to yield crosslinked products and then saponified to give CO2H-containing resins. These can be used for the complexation of heavy metals <79Mi4iioo). 

Metal ions can act as electron-pair acceptors, reacting with electron donors to form coordination compounds or complex ions. The donor species, or ligand, must have at least one pair of unshared electrons to form the bond. Remarkable growth in the analytical applications of complex-formation reactions is attributable to a particular class of coordination compounds called chelates. These compounds are made by the reaction of a metal ion and a ligand that contains two or more donor groups. The properties of chelates can differ markedly from the parent cation. 

At an early stage of the development, the structural information was rather fragmentary. Nowadays, however, the accumulation of structural data for isomers has enabled us to understand structural principles and the optical properties of chelate complexes in considerable detail. In this connection, column chromatography on SP Sephadex has played an important role in the separation of isomers of coordination compounds (2). In view of the large number of structures, a few basic series of structures will be taken up and discussed. 

K. Soga and S. Tomizawa, Electrochemical properties of chelate membranes, Nippon En Gakkaishi (Bull. Soc. Sea Water Sci. Jpn.), 1962, 16, 24. 

As discussed previously flavonoids have the property of chelating bivalent metals. This ability requires a special pattern of substitution which can be supplied by an environment of bivalent negative charges. In the flavonoid structure this requirement is present in the o-hydroxyl substitution, which is often present in the B-ring, and may exist in the... 

Dybcz3mski R., Hubicki Z., Kulisa K. Ion exchange behaviour of 23 elements and amphoteric properties of chelating resin Duolite ES 346 containing amidoxime groups. Solvent Extraction and Ion Exchange 1988 6 699-724. 

Structural and catalytic properties of chelating bis- and tris-N-heterocyclic carbenes 07CCR841. 

Finally, reactivity of the organic group in these solids can be different from that exhibited in solution this is illustrated by the specific properties of chelating units such as the cyclams. Hybrid materials containing cyclams have been prepared [103, 104], It was observed that direct coordination into these solids was very easy. By treating the solid with a solution of CuC in EtOH... 

PauU B and Jones P (1996) A comparative study of the metal selective properties of chelating dye impregnated resins for the IC separation of trace metals. Chro-matographia 42 528-538. 

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