Copper complexes carbon disulfide

AEROPHINE 3418A promoter is widely used ia North and South America, AustraHa, Europe, and Asia for the recovery of copper, lead, and ziac sulfide minerals (see Elotatton). Advantages ia comparison to other collectors (15) are said to be improved selectivity and recoveries ia the treatment of complex ores, higher recoveries of associated precious metals, and a stable grade—recovery relationship which is particularly important to the efficient operation of automated circuits. Additionally, AEROPHINE 3418A is stable and, unlike xanthates (qv), does not form hazardous decomposition products such as carbon disulfide. It is also available blended with other collectors to enhance performance characteristics. 

The name xanthate, derived from the Greek "xanthos (meaning blond), was coined by Zeiss in 1815, because the copper complexes that he isolated had a characteristic yellow color (22). Xanthates are formed by nucleophilic addition of an alkoxide ion to carbon disulfide. 

For the spectrophotometric method, the evolved carbon disulfide is reacted with copper acetate and diethylamine to form a yellow copper complex which can be measured at 435 nm." The recoveries range between 70 and 90%. Reproducibility of this method was improved by reducing the time and the mode of sample pretreatment. Since all alkylenebis(dithiocarbamates) decompose to carbon disulfide by acid degradation, the above analytical methods are not selective. The result is the measured total residues of all alkylenebis(dithiocarbamates) related products. However, this method is recommended as standard method S15 for alkylenebis(dithiocarbamates) by the German Research Association. ... 

Protein-Based Adhesives. Protein-based adhesives are normally used as structural adhesives they are all polyamino acids that are derived from blood, fish skin, casein [9000-71-9], soybeans, or animal hides, bones, and connective tissue (collagen). Setting or cross-linking methods typically used are insolubilization by means of hydrated lime and denaturation. Denaturation methods require energy7 which can come from heat, pressure, or radiation, as well as chemical denaturants such as carbon disulfide [75-15-0] or thiourea [62-56-6]. Complexing salts such as those based upon cobalt, copper, or chromium have also been used. Formaldehyde and formaldehyde donors such as hexametliylenetetraamine can be used to form cross-links. Removal of water from a protein will also often denature the material. 

Two possible mechanisms for the neurotoxicity of carbon disulfide have been suggested. One mechanism involves the formation of dithiocarbamates. The inhibitory effect of carbon disulfide on the activity of the copper-requiring enzyme dopamine- -hydroxylase was attributed to the formation of dithiocarbamates, which can complex copper (McKenna and DiStefano 1977b). Interference with the formation of this metabolite may be a potential strategy, albeit untested, to reduce neurotoxicity from carbon disulfide poisoning. An alternative mechanism postulated to explain the neurotoxic effect of carbon disulfide is the formation of a dithiocarbamate derivative, a form of vitamin B6, of pyridoxamine, with carbon disulfide (Vasak and Kopecky 1967). Since transaminases and amine oxidases require the pyridoxamine phosphate form of vitamin B6 as a cofactor, it was further postulated that these enzymes would be inhibited in carbon... 

Acetates of lead, copper and mercury as simple aqueous solutions, in 1 N acetic acid and as amine complexes, are applied to similar slides. Barium acetate, in neutral and acidic solutions for sulfate and other oxy-thio ions, and other reagents which dissolve sulfur, such as carbon disulfide, may be tried. These require an understanding of their reactions with all substances which may be present or be formed by reactions of such chemicals as are present, to be of diagnostic use. The reader should consultthe chemical literature. 

It is not clear when dithiocarbamates were first prepared, but certainly they have been known for at least 150 years, since as early as 1850 Debus reported the synthesis of dithiocarbamic acids (1). The first synthesis of a transition metal dithiocarbamate complex is also unclear, however, in a seminal paper in 1907, Delepine (2) reported on the synthesis of a range of aliphatic dithiocarbamates and also the salts of di-iTo-butyldithiocarbamate with transition metals including chromium, molybdenum, iron, manganese, cobalt, nickel, copper, zinc, platinum, cadmium, mercury, silver, and gold. He also noted that while dithiocarbamate salts of the alkali and alkali earth elements were water soluble, those of the transition metals and also the p-block metals and lanthanides were precipitated from water, to give salts soluble in ether and chloroform, and even in some cases, in benzene and carbon disulfide. 

Copper complexes of bis(2,2 -dipyridyl)dithiocarbamate have been prepared upon insertion of carbon disulfide into the copper-nitrogen bonds of the corresponding 2,2 -dipyridylamine (dpa) complexes (195, 196). Kumar and Tuck (195) initially noted this behavior for [Cu(dpa)] , [Cu(dpa)2], and [Cu(dpa)(dppe)l [dppe = l,2-bis(diphenylphosphino)ethane], but characterization was made only on the basis of the presence of characteristic v(C—S) and v(C—N) bands in their IR spectra. Later, this was confirmed by the X-ray crystal structure of [Cu(S2Cdpa)2], formed upon slow evaporation of a carbon disulfide solution of [Cu(dpa)2] (Eq. 21) (196). The transformation is actually quite complex as in the dpa complex, metal coordination is through the nitrogen atoms of the pyridyl rings (197), and thus a rearrangement to the amide form must occur prior to carbon disulfide insertion. 

A number of other synthetic routes have also been developed toward copper bis(dithiocarbamate) complexes. Two groups have prepared the bis(2,2 -dipyr-idyl)dithiocarbamate complex 447 (Fig. 221) upon insertion of carbon disulfide... 

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