Copper ammonia complex

Copper alloys are attacked at high pH. However, attack is usually caused not by elevated pH alone but because of copper complexation by ammonia or substituted ammonium compounds. In fact, copper resists corrosion in caustic solutions. For example, corrosion rates in hot caustic soda may be less than 1 mil/y (0.025 mm/y). 

The chromatograms stained with ninhydrin are immersed in the reagent solution for 1 s or sprayed evenly with it and then placed in the free half of a twin-trough chamber containing 25% ammonia solution. Apart from proline and hydroxyproline, which yield yellow copper complexes, all the amino acids yield reddish-colored chromatogram zones [3],... 

Colon of copper complexes. When ammonia is added to 0.2 MCu2. the [Cu(NH3)4]2+ complex ion forms. The ammonia-containing ion is an intense deep blue, almost violet. The hydrated copper complex ion [Cu(H20)4]2+ is light blue. 

Copper and brasses in the systems are more resistant to corrosion because of a stable oxide film however, if ammonia is present together with oxygen, corrosion of copper and copper oxide rapidly occurs. The corrosion is an oxidation process and results in the formation of the ammonia-copper complex [Cu(NH3)42+], Corrosion of nickel and zinc components also may occur in like fashion. 

The valency of the complex radicle is the same as that of the central metallic atom when the complex contains only ammonia, substituted ammonia, water, or other neutral group. For example, cobalt in eobaltie. salts is trivalent, and the cobalt complex with ammonia, Co(NI13)8 ", is likewise trivalent copper in cupric sulphate is divalent, and the copper complex, [Cu(NH3)4] , is also divalent. In the same wn.y [Co(NH3)5.H30] " and [Co(NII3)4.(II20)2] " are trivalent, as also [Co(NH3)2.en2]" and [Co.en3] ", where en represents cthyleucdiamine, CH NH2... 

The most interesting feature of this method, reviewed by Stepanov,62 is the ease with which the halogen atom is replaced by a hydroxyl group during the metallization process. This was first observed as long ago as 1931 when Delfs63 obtained the copper complex of 2-(2-hydroxy-naphthyl-l-azo)phenol-4-sulfonic acid (47) by heating an aqueous solution of l-chloro-2-(2-hydroxynaphthyl-l-azo)benzene-4-sulfonic acid (48), copper sulfate, sodium hydroxide and ammonia at 80 °C for 1 hour. 

Despite the expenditure of a tremendous amount of effort throughout the world, the two original methods employed in the manufacture of copper phthalocyanine are still used. In the first, a mixture of phthalic anhydride, urea and copper(I) chloride is heated in a high-boiling solvent such as nitrobenzene or trichlorobenzene in the presence of a catalytic amount of ammonium molybdate. The crude copper phthalocyanine is filtered off and the solvent recovered by distillation. The urea acts as a source of nitrogen and the first step in the overall reaction (equation 18) is conversion of phthalic anhydride to phthalimide (219) by ammonia liberated by the urea. More ammonia then converts the phthalimide to l-keto-3-iminoisoindoline (220) and finally to l-amino-3-iminoisoin-dolenine (221). All three intermediates have been isolated and identified. In the presence of copper chloride the l-amino-3-iminoisoindolenine undergoes conversion to the copper complex of phthalocyanine. 

In the solid state, the metal atoms in bis(salicylaIdoximato)copper(II) show two additional contacts with the oxime oxygens of adjacent molecules, resulting in a distorted octahedral structure. However, the axial Cu—O distance (2.66 A) is much longer than the metal—ligand distances in the square-planar array (Cu—O, 1.92 A and Cu—N, 1.94 A).154 Studies by ESR of copper(II) extracts of the commercial reagent SME 529 (14 R = Me, R = C9H)9) have shown that the copper complex exists as a square-planar species in hydrocarbon solutions, but that five-coordinate adducts are formed in the presence of ammonia or pyridine.155... 

In the case of copper(I) ammonia complexes, Cu(NH3)2+ is formed with log 02 = 10.9 and higher complexes cannot be detected, in close analogy to the silver(I) Ag(NHs)2 having log 02 = 7.0. On the other hand, copper(II) turned out to be considerably more complicated. It is true that between 0.08 and 0.3 M NH3, more than... 

Copper Complexes. The preparation of copper and nickel complexes of tridentate metallizable azo and azomethine dyes is easily carried out in aqueous media with copper and nickel salts at pH 4-7 in the presence of buffering agents such as sodium acetate or amines. Sparingly water soluble precursors can be metallized in alkaline medium at up to pH 10 by using an alkali-soluble copper tetram(m)ine solution as coppering reagent, which is available by treating copper sulfate or chloride with an excess of ammonia or alkanolamines [3],... 

In demethylative coppering to give the bis-copper complex 22 [74592-99-7] (3 Na, Li salt) [36], the sodium salt of the disazo compound made by coupling of bis-diazotized 3,3 -dimethoxy-4,4 -diaminodiphenyl with two equivalents of 8-amino-l-hydroxynaphthalene-3,6-disulfonic acid in alkaline medium is dissolved in water by adding diethanolamine. An ammonia alkaline copper(n) sulfate solution made from CuS04-5 H20 and of ammonia are added. The mixture is heated at 80-90 °C for 14 h. The solution is then cooled to 40 °C and the bis-coppered dye 22 salted out with sodium chloride. It dyes cotton in lightfast blue shades. 

Preparation 3 illustrated the formation of a double salt, ammonium copper sulphate, (NH SCh-CuSCh-OI O. In the double salt, ammonium plays the part of a positive radical. In the present preparation ammonia plays an altogether different role. It does not possess a primary valence, and it enters into a molecular compound with the salt by virtue only of a secondary valence. In fact, the ammonia in this preparation is held in the same sort of a combination as the water in the hydrate CuS04-5H20. The molecules of ammonia would appear to be bound to the copper rather than to the sulphate radical, because when the salt is dissolved in water the four ammonia molecules remain in combination with the copper as the complex ion Cu(NH3)4++, while the sulphate radical appears as the ordinary SO4 ion. Thus we might say that this salt is the sulphate of the ammonio-copper complex. (Cf. Ammoniates, page 118.)... 

Copper and its alloys are resistant to alkalies with the exception of ammonium hydroxide and cyanides. Ammonium ions promote stress-corrosion cracking of copper and its alloys. Ferric and stannic salts are aggressive towards copper alloys. Ammonia and cyanide ions form tetramine copper and tetracyano copper complexes in ammonia and cyanide solutions, respectively. 

The new product is commonly known as the copper-ammonia complex ion, or more officially, hexamminecopper(II). This equation is somewhat misleading, however, in that it implies the formation of a new complex where none existed before. In fact, since about 1895 it has been known that the ions of most transition metals dissolve in water to form complexes with water itself, so a better representation of the reaction of dissolved copper with ammonia would be... 

The chlorides, nitrates, and sulphates of the cations of the copper sub-group are quite soluble in water. The sulphides, hydroxides, and carbonates are insoluble. Some of the cations of the copper sub-group (mercury(II), copper(II), and cadmium(II)) tend to form complexes (ammonia, cyanide ions, etc.). 

The chemical reactions and mechanism of fixation of the am-moniacal preservatives such as ACA have not been studied extensively. The main mechanism of fixation is believed to be the formation of insoluble copper arsenate upon evaporation of the ammonia. However, the overall mechanism is undoubtedly more complex because cuprammonium ions react by ion exchange with functional groups, such as carboxyl, in wood (52). In addition, copper complexes can be formed with cellulose (52). 

Chelex-100 (Whatman) resin was suspended in 1 M CuCl2 overnight, washed repeatedly in water and suspended in 1 N ammonia overnight. A column (0.9 x 45 cm) was packed with a small volume of non-CuCl2 treated resin at the bottom followed by the copper complexed resin above. After washing the column, the nucleic acid components were loaded in a small volume of water and eluted with water (nucleotides followed by weakly basic nucleosides), 1 N ammonia (other nucleosides) and/or 2.5 N ammonia (bases). The nucleotides are not bound by the column and so are not fractionated. The nucleosides and bases are, however, well fractionated. Several minor components are well separated. The method is relatively quick and the eluants are volatile. 

Among the best-known nonderivatizing solvent systems is a combination between copper, alkali, and ammonia termed Schweizer s reagent. Solutions of cuprammonium hydroxide have been used for both analytical and industrial cellulose dissolution. Regenerated fibers with silk-like appearance and dialysis membrane have been (and partially continue to be) industrial products on the basis of cellulose dissolution in cuprammonium hydroxide. The success of this solvent is based on the ability of copper and ammonia to complex with the glycol functionality of cellulose as shown inO Fig. 11. Because of the potential side reactions (oxidation and crosslinking, Norman compound formation), alternatives to both ammonia as well as copper have been developed. Cuen and cadoxen are related formulations based on the use of ethylene diamine and cadmium, respectively. The various combinations of alkali, ammonia. 

The beaker on the left in Figure 10 contains this copper complex ion reaction in a chemical equilibrium that favors the formation of reactants. We know that the reverse reaction is favored, because the reaction mixture in the beaker is pale blue. But if additional ammonia is added to this beaker, the system responds to offset the increase by forming more of the product. This increase in the presence of product can be seen in the beaker to the right in Figure 10, which contains a blue-purple solution. 

For the copper complexes the residual effect is positive and the successive stability constants decrease in regular order. For the zinc-ammonia complexes, the residual effect is negative and the first three stability constants are about equal. 

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