Chelated copper

Chelucci et al. [41] synthesized further chiral terpyridines derived from (-)-yd-pinene, (-i-)-camphor, and (-l-)-2-carene and tested their ability to chelate copper or rhodium for the asymmetric cyclopropanation of styrene. The copper catalysts were poorly efficient and selective in this reaction. The corresponding rhodium complexes led to the best result (64% ee) with the ligand derived from (-l-)-2-carene (ligand 33 in Scheme 17). 

The P-alanyl dipeptides carnosine and anserine (A -methylcarnosine) (Figure 31-2) activate myosin ATPase, chelate copper, and enhance copper uptake. P-Alanyl-imidazole buffers the pH of anaerobically contracting skeletal muscle. Biosynthesis of carnosine is catalyzed by carnosine synthetase in a two-stage reaction that involves initial formation of an enzyme-bound acyl-adenylate of P-alanine and subsequent transfer of the P-alanyl moiety to L-histidine. 

Treatment for Wilson disease consists of a diet low in copper along with Ufelong administration of penicillamine, which chelates copper, is excreted in the urine, and thus depletes the body of the excess of this mineral. 

Native, multi-subunit KLH also should not be frozen. Freeze-thaw effects cause extensive denaturation and result in considerable amounts of insoluble material. Commercial preparations of native KLH are typically freeze-dried solids that no longer fully dissolve in aqueous buffers and do not display the protein s typical blue color due to loss of chelated copper. The partial denatured state of these products often makes conjugation reactions difficult. 

Another relatively simple approach is that of Stolzberg and Rosin [419]. The sample is spiked with an excess of copper, then passed through a Chelex 100 column. The column retains the free copper ion, but passes the copper associated with strong ligands. The chelated copper eluted from the column is measured by plasma emission spectrometry. 

Copper sulfate is used to control protozoan fish ectoparasites including Ichthyopthirius, Tri-chodina, and Costia. The effectiveness of the treatment diminishes with increasing total alkalinity and total hardness of the water (Straus and Tucker 1993). Copper compounds now used to control protozoan parasites of cultured red drum (Sciaenops ocellatus) include copper sulfate, copper sulfate plus citric acid, and chelated copper compounds (forms of copper bound by sequestering agents, such as ethanolamine) chelated copper compounds are considered less toxic to fish than copper sulfate and at least as effective in controlling parasites (Peppard etal. 1991). 

Miltimore, J.E., C.M. Kalnin, and J.B. Clapp. 1978. Copper storage in the livers of cattle supplemented with injected copper and with copper sulfate and chelated copper. Canad. Jour. Anim. Sci. 58 525-529. 

Peppard, E.M., W.R. Walters, J.W. Avault, Jr., and W.G. Perry, Jr. 1991. Toxicity of chelated copper to juvenile red drum Sciaenops ocellatus. Jour. World Aquacult. Soc. 22 101-108. 

Straus, D.L. and C.S. Tucker. 1993. Acute toxicity of copper sulfate and chelated copper to channel catfish Ictalurus punctatus. Jour. World Aquacult. Soc. 24 390-395. 

Special consideration should be paid to metal complexes such as azomethine pigments (Sec. 2.10). At high temperatures, the yellow copper complex with the chemical constitution 10, incorporated in PVC, will exchange its chelated copper atoms with the metal atoms present in the application medium. Stabilizers containing barium/cadmium or lead produce yellow shades, while dibutyl tin thiogly-colate or other tin compounds produce a brilliant medium red. Color change is slow at low temperatures, but at 160°C the effect is rapid [108],... 

The method described below will use the complexing reagent DTPA (diethylene-triaminepentaacetic acid) to extract, by chelation, copper, iron, manganese and zinc (including zinc on calcareous soils) it also shows promise for monitoring cadmium, nickel and lead in soils receiving sludge appli-... 

Penicillamine (Cuprimine) can be used to treat acute, severe rheumatoid arthritis, producing reductions in joint pain, edema, and stiffness. The response to penicillamine is usually delayed (4-12 weeks), and remissions can last several months after withdrawal of treatment. Radiographic evidence of this drug s efficacy is limited thus, penicillamine is seldom used to treat rheumatoid arthritis. The mechanism of action of penicillamine is unknown, but some evidence suggests that it may involve the inhibition of angiogenesis, synovial fibroblast proliferation, or transcriptional activation. Because penicillamine can chelate copper and promote its excretion, it is used to treat Wilson s disease (hepatolenticular degeneration) and has also been used in mercury and lead intoxication. 

Mechanism of Action A heavy metal antagonist that chelates copper, iron, mercury, lead to form complexes, promoting excretion of copper. Combines with cystine-forming complex, thus reducing concentration of cystine to below levels for formation of cystine stones. Exact mechanism for rheumatoid arthritis is unknown. May decrease cell-mediated immune response. May inhibit collagen formation. Therapeutic Effect Promotes excretion of copper, prevents renal calculi, dissolves existing stones, acts as anti-inflammatory drug. 

Dr. Anbar Good. Now, why do you suppose that a chelated copper ion is more likely to form the hydride than a nonchelated hydride ... 

Reaction of the intramolecular chelating copper afkoxides 121 or 122 with (Me3Si)3 CZnCl afforded complexes 123 and 124 (equation 22) . In these complexes the copper bis(alkoxide) moiety acts as an 0,0-chelating ligand coordinated to zinc. 

This system treats about 15 gpm of chelated copper waste streams (including EDEA-chelated copper) and recovers up to 7 kg/day of the metal. It eitploys a... 

From a thermodynamic viewpoint, all living matter is extremely unstable with respect to combustion by oxygen. Ordinarily, a high temperature is required and if we are careful with fire, we can expect to escape a catastrophe. However, one mole of properly chelated copper could catalyze consumption of all of the air in an average room within one second.174 Biochemists are interested in both the fact that 02 is kinetically stable and unreactive and also that oxidative enzymes such as cytochrome c oxidase are able to promote... 

The rhodium(II) catalysts and the chelated copper catalysts are considered to coordinate only to the carbenoid, while copper triflate and tetrafluoioborate coordinate to both the carbenoid and alkene and thus enhance cyclopropanation reactions through a template effect.14 Palladium-based catalysts, such as palladium(II) acetate and bis(benzonitrile)palladium(II) chloride,l6e are also believed to be able to coordinate with the alkene. Some chiral complexes based on cobalt have also been developed,21 but these have not been extensively used. 

Ku, Y. and Chen, C., Removal of chelated copper from wastewaters by iron cementation, Indust. Eng. Chem. Resources, 31, 1111-1115, 1992. 

Figure 5-70. The hydrolysis of the ester 5.32 is accelerated by copper(n) salts. The initial step is the formation of the chelated copper(n) complex, followed by intramolecular attack of co-ordinated hydroxide upon the co-ordinated ester group.

Keen et al.86 have demonstrated the prophylactic value of copper(II) chelated by NTA for Menkes disease by using as a laboratory model the crinkled mutant mouse. As this syndrome does not respond to dietary supplementation with either copper sulphate or copper acetate then therapy with chelated copper would appear to have advantages. 

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