Cadmium complexes formate

Gardiner J. (1974) The chemistry ofcadmium in natrrral water 1. A study of cadmium complex formation using the cadmium specific-ion electrode. Water Res. 8, 23—30. 

Several solvents, such as cupriethylenediamine (cuen) hydroxide [111274-71 -6] depend on the formation of metal—ion complexes with ceUulose. Although not as widespread in use as the viscose process, cuen and its relatives with different metals and ammonium hydroxide find substantial industrial use (87). The cadmium complex Cadoxen is the solvent of choice in laboratory work (91). 

According to R. Brdicka and K. Vesely the carbonyl form of formaldehyde is reduced and the limiting kinetic current is given by the rate of the chemical volume reaction of dehydration. An analogous situation occurs for the equilibria among complexes, metal ions and complexing agents if the rates of complex formation and decomposition are insufficient to preserve the equilibrium. A simple example is the deposition of cadmium at a mercury electrode from its complex with nitrilotriacetic COO"... 

Studies of the thermodynamics of formation of complexes of zinc with 2,2 -bipyridine in the presence of halide and thiocyanate ions in DMF has been carried out.205 The zinc complexes of 2,2 -bipyridine with A-(benzenesulfonyl)glycine and A-(toluene- -sulfonyl)glycine were synthesized and infrared data implied a structural analogy with the cadmium complexes. This suggests that the zinc promotes sulfonamide nitrogen deprotonation in the amino acid ligands in the solid state.206... 

The Department of the Environment UK [155] has described a number of alternative methods for the determination of total oxidised nitrogen (nitrate and nitrite) in aqueous solution, while specific methods for nitrate and nitrite are also included. Among the methods for total oxidised nitrogen, one is based on the use of Devarda s alloy for reduction of nitrate to ammonia, and another uses copperised cadmium wire for reducing nitrate to nitrite, which is determined spectrophotometrically. Nitrate may also be determined spectrophotometrically after complex formation with sulfosalicylic acid or following reduction to ammonia, the ammonia is eliminated by distillation and determined titrimetrically. Other methods include direct nitrate determination by ultraviolet spectrophotometry, measurements being made at 210 nm, and the use of a nitrate-selective electrode. Details of the scope, limits of detection, and preferred applications of the methods are given in each case. 

Kounaves and Zirino [ 145] studied cadmium-EDTA complex formation in seawater using computer-assisted stripping polarography. They showed that the method is capable of determining the chemical speciation of cadmium in seawater at concentrations down to 10 8 M. 

In contrast to the ionic complexes of sodium, potassium, calcium, magnesium, barium, and cadmium, the ease with which transition metal complexes are formed (high constant of complex formation) can partly be attributed to the suitably sized atomic radii of the corresponding metals. Incorporated into the space provided by the comparatively rigid phthalocyanine ring, these metals fit best. An unfavorable volume ratio between the space within the phthalocyanine ring and the inserted metal, as is the case with the manganese complex, results in a low complex stability. 

The electrochemical properties of Cd(II) complexes with inorganic ligand presented in early papers were discussed by Hampson and Latham [72]. Later, electrochemical investigations of cadmium complexes were oriented on the mechanism of complex formation, determination of stoichiometry and stability constants, mechanisms of reduction on the electrodes, and evaluation of kinetic parameters of these processes. The influence of ligands and solvents on stability and kinetic parameters of electroreduction was also studied. 

Electrochemical oxidation of cadmium in a solution of ](4-methylphenyl)sulfonyl]-2-pyridylamine] (HL) in acetonitrile/di chloromethane mixtures resulted in CdL2 complex formation [149]. The electrochemical oxidation of cadmium amalgam in nonaqueous solvents CH2CI2, 1,2-C2H4CI2, and PC was also used for the preparation of cadmium complexes with 18-membered macromonocyclic ligands, 18-06, 18-S6, I8-N2O4, and 18-N6 [150]. The stoichiometry and stability of resulted complexes were determined. The same method was used to examine the complexation of Cd(II) cation with 12-crown-4 ether, azacrown ether 1,4,8,11-tetra-azacyclotetradecane, and thiaazacrown... 

The distribution coefficients determined for cadmium (at ll C) are given in Figure 3- The coefficients appear somewhat less than the corresponding data for strontium and barium. Such results could be due to either anionic complex formation (22) and/ or a less favorable sorption equilibrium. 

Cadmium complexes of macrocyclic ligands have not been as widely studied as the corresponding zinc complexes, but the fact that cadmium macrocycles undergo easy metal exchange should make them attractive subjects for future study. The crystal structure of [Cd(TPP)(dioxane)j and its 113CdNMR characteristics have been reported.1144 The formation... 

The only successful isolation of the parent compound of the oxa-diazole homologs came about through complex formation with cadmium chloride39,160 as shown in Eq. (66). Oxadiazole was then distilled away from the purified complex at 30° under reduced pressure. 

Cadiot-Chodkiewicz reaction, for C-C bond formation, 11, 19 Cadmate complex, formation, 2, 465 Cadmium-carbon bond formation, overview, 2, 462 Cadmium reagents... 

Cabrera, D., Young, S.D. and Rowell, D.L. (1988) The toxicity of cadmium to barley plants as affected by complex formation with humic acid. Plant Soil, 105, 195-204. 

The retardation of chloride and sulphate through complex formation with cadmium enabling the separation of anions of interest [28] to be carried out, was found to be unsuitable, as the high concentration of cadmium ions necessary to achieve the desired effect led to the loss of fluoride and phosphate (probably owing to precipitation). 

There is a marked contrast between zinc and cadmium in the context of complexing of the 2+ ions with bipy, studied by high-pressure stopped-flow. There is a striking difference between the two elements, with Zn + reacting progressively more slowly with bipy as pressure increases, Cd + more rapidly. The Activation Volume (Ay ) for the zinc reaction is -1-7.1 cm mol whereas for cadmium the value is -5.5 cm mol . These values suggest that the substitutions are 7d and 4 in character respectively. AT values for the reverse, dissociation, reaction and A " values for formation and for dissociation, are all consistent with this assignment of mechanism. Positive activation volumes for a few other substitution reactions at Zn +aq also indicate h mechanisms, as proposed many years ago in discussions of ultrasonic data on complex formation from Zn +aq. 

Ligand properties of surface silanol groups. I. Surface complex formation with iron (3+), copper (2+), cadmium (2+) and lead (2+), J. Colloid Interface Sci. 55, 469-475 (1976). ... 

Metal complex formation can be used to stabilize an otherwise reactive or unstable organic developer, such as hydroquinone or p-phenylenediamine, to permit its incorporation into silver halide emulsion layers or adjacent layers. For example, catechols and hydroquinones can be mixed with several metal salts of lead(II), cadmium or barium and incorporated into emulsion layers. Treating the film with an activator solution containing an anion that forms an insoluble salt of the metal ion (S04 , liberates the organic developer.The structures of the complexes... 

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