Cadmium complexation

A second synthesis of cobyric acid (14) involves photochemical ring closure of an A—D secocorrinoid. Thus, the Diels-Alder reaction between butadiene and /n j -3-methyl-4-oxopentenoic acid was used as starting point for all four ring A—D synthons (15—18). These were combined in the order B + C — BC + D — BCD + A — ABCD. The resultant cadmium complex (19) was photocyclized in buffered acetic acid to give the metal-free corrinoid (20). A number of steps were involved in converting this material to cobyric acid (14). 

Table 3. Thermodynamic and Stability Constant Data for Selected Aqueous Cadmium Complexes ...

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). 

Chelates are often named merely as a complex, eg, cadmium complex with acetylacetone. A common practice ia the Hterature is to give the symbol of the central atom and an abbreviation for the ligand with or without an iadication of ionic charges, oxidation states, stmcture, or counterions, as ia the foUowiag Pb-EDTA, Cacit , Cu(en)2, Co(II)-(phen), [Cu(dipy)2]S04, [Ru(dipy)2(en)], and Na[Co(acac)2]. Ligand abbreviations are given ia Table 1. 

Porphyrin, octaethyl-, cadmium complex cyclic voltammetry, 4, 399 <73JA5I40)... 

The measurment in twophase systems is discussed by the example of dithizonate of zinc, in pseudomonophase systems - by the example of zinc and cadmium complexes with l-(2-pyridylazo)-2-naphthol, lanthanoid ion complexes with l-(2-pyridylazo)-resorcin. 

Bis(pentafluorophenyl)cadmium complexes have been used to prepare tri-methyl(pentafluorophenyl)tin [4 (equation 15)... 

Cadmium complex. 4C s H5 N.Cd(MnC>4)2 violet tubular crysts, apparently rhombic. It was prepd by mixing coned solns of pyridine (4 moles) and Cd(Mn04)2 (lmole) at 0°. V sol in w expids at about 65°... 

Cadmium complexes acety(acetone, 2, 372 alcohols, 5, 964 amides, 5,944 amine oxides, 5,964 amines, 5,933 amino acids, 5, 938... 

Munoz, A., Laib, F., Petering, D.H. and Shaw, C.F. Ill (1999) Characterization of the cadmium complex of peptide 49-61 a putative nudeation center for cadmium-induced folding in rabbit liver metallothionein IIA. Journal of Biological Inorganic Chemistry, 4, 495—507. 

Bayer and Schretzmann 25) came to the conclusion that reversible oxygenation is a characteristic property of group VIII metals. However, work has shown that the cadmium complex CdEt2 can take up dioxygen reversibly in the ratio 1 2 (Cd O2). But it was found that the oxygenated complex (II(P) or 11(G) orientation) can undergo spontaneous catalytic oxidation to form bis(ethylperoxy) cadmium ... 

For 1,3Cd NMR studies on poly(pyrazolyl)borato cadmium complexes, see ... 

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... 

Figure 25 Structure of bis[methyl(w-hexyl)dithio-/selenocarbamato]-zinc and -cadmium complexes,...

Stolzberg [143] has reviewed the potential inaccuracies of anodic stripping voltammetry and differential pulse polarography in determining trace metal speciation, and thereby bio-availability and transport properties of trace metals in natural waters. In particular it is stressed that nonuniform distribution of metal-ligand species within the polarographic cell represents another limitation inherent in electrochemical measurement of speciation. Examples relate to the differential pulse polarographic behaviour of cadmium complexes of NTA and EDTA in seawater. 

Originally, the stoichiometric stability constants 6 for the lead and the cadmium complexes with chloride had been determined in NaCl-NaC104 solutions and it had been assumed that the NaCl was completely dissociated. The nominal ionic strength was one molal. The constants were later corrected by replacing the actual free chlorides for the total chlorides in the calculation of... 

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