Complexes of cadmium

Complexes of cadmium include, besides those already mentioned, a tetracyanocadmiate [Cd(CN)4] which in neutral solution is sufficiently unstable to allow precipitation of cadmium(II) sulphide by hydrogen sulphide. Octahedral [CdCl ] ions are known in the solid state, as, for example, K4CdCl5. 

Rabinovich D (2006) Poly(mercaptoimidazolyl)borate Complexes of Cadmium and Mercury 120 143-162... 

Bruland, K. W. (1992). Complexation of cadmium by natural organic ligands in the central North Pacific, Limnol. Oceanogr., 37, 1008-1017. 

Continuous monitoring methods based on amperometric (Nikolic et al. 1992) or spectrophotometric (Kuban 1992 Ma and Liu 1992) techniques for the quantification of free cyanide are also available. Ion chromatography with amperometric determination provides good sensitivity (2 ppb) and selectivity for free cyanide and the weak complexes of cadmium and zinc (Rocklin and Johnson 1983). Postcolumn derivatization and fluorescence detection provides low detection limits as well (0.1 ppb) (Gamoh and Imamichi 1991). 

The cadmium complexes were also investigated potentiometrically. Using this method, the complexes of cadmium with asparagine [128], taurine [129], A -(6-ami-no-3-methyl-5-nitroso-4-oxo-3,4-dihydro-pyrimidin-2-yl)glycine [130], succinate and malate [131], acetate at different temperatures [132], pyridine oxime ligands [133], 2-hydroxypropene-l,3-diamine-Af,Af,Af, A -tetraacetic acid [134] were studied. The stoichiometry and stability constants of these complexes were determined. 

A considerable number of NQR studies have been made on zinc and cadmium complexes, for example, the 35C1, 81Br and 127I NQR spectra of a number of CdX2-polyether complexes have been reported and indicate that the compounds are dimeric in solution, with symmetrical halogen bridges between the metal atoms.69 A number of amino acids and peptide complexes of cadmium(II) have been investigated by 14N NQR spectroscopy.70... 

The preparation of some mixed ethylenediamine-oxalate or other ligand complexes of cadmium(Il) has been reported.190-192 The reaction of a mixture of cadmium oxalate and CdX2 (X = Cl, Br, I or SCN) with ethylenediamine gives the complexes Cd(en)X(C204)o.s. The... 

The crystal structure of [Cd(GlyGly)(Im)Cl] has been reported72 and shown to involve dimeric units with a distorted octahedral geometry about each metal atom this complex has also been studied in a 13C NMR investigation of a range of nucleoside and peptide complexes of cadmium(II).430... 

Support for the above conclusions was also obtained from an analysis of the Cd NMR and solid state MAS spectra of the five, six, and seven coordinate cadmium texaphyrin complexes 116, 156, and 157, respectively [70]. From the solid-state MAS results, a single tensor was observed for the five-coordinate complex 116 with a corresponding isotropic chemical shift of 194 ppm. The MAS spectrum of a complex prepared in the presence of pyridine, however, revealed two tensors, presumed to be due to a mixture of six and seven coordinate species. Based upon the isotropic chemical shifts and the symmetry of the tensors the six coordinate species was assigned to the isotropic shift at 188 ppm and the seven coordinate species assigned to the isotropic shift at 221 ppm. The MAS spectrum of the benzimidazole complex of cadmium texaphyrin consists of only a single... 

Since an ambidentate ligand possesses at least two groups capable of coordinating to metal ions, polynuclear complexes may also exhibit linkage isomerism. The selenocyanate complex of cadmium , [(C4H9)4N]2 [Cd2(CNSe)6], contains the dimeric anion on the next page,... 

Rook, J. J. (1979). Complexation of cadmium(Il) with water- and soil-derived fulvic acids Effect of pH and fulvic acid. Can. J. Chem. 57, 1263-1268. 

Extraction of the cadmium-iodide complex from iodide-H2S04 solutions with oxygen-containing solvents (e.g., mesityl oxide, 2-ethyl-1-butanol) is a selective recommended separation method (e.g., from zinc) [1-3]. The iodide complex of cadmium can also be extracted with high molecular weight amines in xylene [4], TBP in benzene [5], and with tetra-n-butylammonium iodide in CHCI3 [6]. 

The anionic bromide- [18,19] and iodide- [20] complexes of cadmium can also be retained on anion-exchangers. 

The cationic complex of cadmium with 1,10-phenanthroline forms with acid dyes the ion associates which have become a basis for extraction-spectrophotometric methods of determining cadmium. Among the dyes used are Rose Bengal (CHCI3, e = 1.0-10 ) [58,59], Erythrosin (e = 9.6-10 ) [60], dibromofluorescein [61], Bromophenol Blue (CHCI3, e = 5.6-10 ) [62,63], and Thymol Blue [64]. 

The macrocycle, tetramethyltetra-azacyclotetradecane (4-Me-cyclam-14), gives selectively with Cd a cationic complex that can be extracted with the acid dye Erythrosin as counter-ion into CHCI3 (e = 1.1-10 at 550 nm) [65]. The cationic complex of cadmium with cryptand(2.2.1), associated with Erythrosin, has been also applied for determining Cd (nitrobenzene-toluene, e = 1.05-10 ) [66]. 

GOL/AND2] Golub, A. M., Andreichenko, O. E., Selenocyanato-complexes of cadmium, Rms. J. Inorg. Chem., 7, (1962), 279-283. From a citation in this Bibliography... 

D. Inman, Complex Ions in Molten Salts A Potentiometric Study of the Halide Complexes of Cadmium in Molten Equimolar NaN03-KN03 at 250 °C, Electrochim. Acta 10 (1965) 11-21. 

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