Cadmium, thiolate complexes

The cadmium thiolate complexes [Cd(Tm/ Tol)(SR)] (R = Bn, Ph, p-Tol, C6F5) were prepared by the reaction of [CdBr(Tm/ "To1)] with equimolar amounts of the corresponding thallium thiolates. [CdSPh(Tm/7"To1)] is a four-coordinate species exhibiting a distorted tetrahedral geometry in the solid state.53... 

The cadmium-thiolate complexes (Table 6) have the greatest known shifts to lower shielding (24). Magnetic circular dichroism indicates near tetrahedral symmetry about cadmium, and it is suggested that the greatest deshielding is from total... 

Several crystal structures of cadmium-thiolate complexes with nuclearity higher than 4 can be found in the literature. For example, the octanuclear molecule [Cdg(SPhF-3)i4(DMF)6(N03)](N03) [97] (Figure 27) consists of a cubic cluster... 

Cf produces two fission products that travel in opposite directions. If one projectile hits the sample, ions will be produced. These ions may then be focused and measured by TOF MS. The other projectile may be used to measure the start of the ionization process. This method has been used to study the ions produced from the ionization of metal complexes such as cadmium thiolates (33) and lanthanide phthalocyanine complexes (34). This method has also been used on metal oxides such as La203 to produce metal oxide cluster ions (35). 

The electrochemical synthesis of cadmium and zinc thiolate complexes and their properties were reviewed in addition to other metal ion complexes [152]. 

A structural analog for the Cys4Zn motif of the ADA protein is constituted by the thiolate complex [ZnSPh(Tmph)].132 Related cadmium complexes have been also described.149 These studies are also pertinent to other enzymes that feature cysteine thiolate alkylation such as methionine synthase, methanohcoenzyme methyltransferase, farnesyl transferase. 

Cadmium thiolates considered here include those compounds that, if mononuclear, only involve ligation by organothiolate anions (RS ) and, if polynuclear, only contain these groups as skeletal bridging ligands. A nice review on the structural chemistry of metal thiolate complexes was published in 1986 by Dance [80],... 

Figure 1 illustrates the change of the stability order, where the log fi values of monoligand cadmium(II) complexes are depicted together with those of the corresponding zinc(II) complexes. It is obvious from this figure that all amino acids form more stable complexes with zinc(II) than with cadmium(II) but the presence of the thiolate function results in an enhanced stability and the opposite trend of complex stability. 

In the case of the common peptides the comparison of the stability constants of zinc(II) and cadmium(II) complexes reveals the same trends as reported for the amino acids Favored complexation with zinc(II) in almost all cases, except for the thiolate ligands. The binding of several side chain residues may enhance the stability of cadmium(II) complexes but the extent of this stabihzation is relatively low. This is true even for the aspartyl or histidyl residues which are generally considered as the most strongly coordinating side chains in the corresponding... 

CdS Nanoparticles Thermal decomposition has been one of the most efficient pathways for synthesizing CdS nanoparticles. In a typical thermolysis process, a cadmium thiolate powder is heated so as to nucleate CdS particles which are then grown to the desired size by controlled reaction of precursor molecules. Some of the major synthesis methods used are summarized in Table 2. A single source precursor made by reacting cadmium metal ions and a molecule containing the sulphur in a complexing solution of trioctylphosphine (TOP), trioctylphosphineoxide (TOPO), hexadecylamine (HDA), tetradecylamine (TDA) trioctylamine (TOA) or dodecylamine (DA) has been used to produce CdS nanoparticles [197-201]. 

Zinc and cadmium complexes of the novel tripod ligand (145) have also been described.1087 The reaction of Hg(HL)2 (HL = 2-mercaptobenzoic acid, 146) with cadmium nitrate leads to the novel CdHgL species, in which the cadmium is bonded to the carboxylate oxygen atom, and the mercury to the thiolate sulfur.1088... 

Tripod ligands of the pyrazolyl/thioimidazolyl-borate offering N2S, NS2, and S3-donor sets were employed in the study of biologically relevant alkylations of the R-thiolate zinc complexes (R = ethyl-, benzyl-, phenyl-, and p-nitrophenyl).78 A review recently described the use of poly(mercaptoimidazolyl)-borate in the chelation of cadmium and mercury.107... 

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