Cadmium Derivatives Research Articles

The direct electrochemical synthesis of zinc and cadmium derivatives of α,ω-alkanedithiols and their reaction with carbon disulphide

The anodic oxidation of zinc or cadmium in non-aqueous solutions of α,ω-alkanedithiols, HS(CH 2) n SH ( n=2−6) gives the corresponding M[S 2(CH 2) n ] species in high yield. When 2, 2′- bipyridine or 1, 10-phenanthroline are present in the cell, the products are the appropriate 1:1 adducts. These compounds react with carbon disulphide, but in general only one of the two MSC sites undergoes attack. The products are complexes involving one thiolato and one thioxanthato group in the ligand, and the thioxanthate is in the exocyclic ▪ mode.

Zinc and Cadmium Derivatives of Tris(1-Pyrazolyl)Methane

Abstract Tris(1-pyrazolyl)methane, L, gives thermally stable LMX2, L2MI2, and octahedral [L2M]Z2 species, where M is zinc or cadmium, X may be Cl, Br, I, or trifluoroacetate, and Z is perchlorate or tetrafluoroborate. Conductivity, infrared, and nmr spectra (1H and 13C), show that these compounds are not stable in the few solvents in which they dissolve, i.e. dimethylsulphoxide and, to a lesser extent, methanol due to ligand displacement.

On coordination modes of adenine in cadmium(II) complexes

Complexes of cadmium(II) derivatives with adenine from water or by simulation of physiological conditions are obtained. The complexes have been studied by spectroscopic, conductometric, 1H-NMR and by TG and DSC measurements. Possible coordination modes of the ligand are proposed.

Comparative Cd-113 nuclear magnetic resonance studies of Cd(II)-substituted blue copper proteins.

The 113Cd NMR spectra of plastocyanin (Spinacea), stellacyanin (Rhus vernicifera), and two azurins (Pseudomonas aeruginosa and Alcaligenes faecalis) have been measured after introducing Cd(II) into the blue copper-binding sites. Relative to Cd(C1O4)2 the chemical shifts are 432, 380, 372, and 379 ppm, respectively, all of which are found to be reasonable values for binding sites containing a cysteine thiolate ligand. The 113Cd resonances of the cadmium derivatives of stellacyanin and the azurins are so near the same that the proteins must present very similar metal-binding sites. In contrast the plastocyanin derivative resonates about 50 ppm further downfield which may signal a change in coordination number. The spin lattice relaxation times of the 113Cd resonances are of the order of 0.1 s, and a major portion of the relaxation apparently occurs through the chemical shift anisotropy mechanism. At 13 degrees C the 113Cd resonance of Psuedomonas azurin shifts slightly downfield with increasing pH. This is explained by a small change in the environment about cadmium which occurs as a result of the conformational change that attends the titration of His-35.

Coordination chemistry of benzoxazole-2-thione. Complexes of some transition metal acetates, tetrafluoroborates, sulphates and nitrates

Abstract Several complexes of cobalt(II), nickel(II), copper(II), copper(I), zinc(II), cadmium(II)and mercury(II) acetate, tetrafluoborate, sulphate and nitrate with benzoxazole-2-thione have been prepared and characterized by chemical analyses, ligand-field spectra, magnetic susceptibility measurements, molecular conductances and vibrational spectra (conventional and far i.r.). In the light of spectroscopic investigation it is possible to distinguish whether the anions present are coordinated to the transition metal ion or are present as free ions. Spectroscopic parameters of the cobbalt(II) and nickel(II) complexes are compared with similar chromophores containing sulphur, oxygen and nitrogen donor atoms. The evidence suggests that the sulphato- and nitrato-derivatives of cobalt and nickel are tetrahedral, the nickel tetrafluoroborato-derivative resulted octahedral, while the nickel acetato-complex and the complexes of the cobalt acetate and tetrafluoroborate resulted square planar and in predominantly planar environment respectively. The zinc, cadmium and mercury derivatives with a 1:2 and 1:3 metal:ligand molar ratio have a tetrahedral symmetry with the exception of[Znbot 2 Ac 2 ] which resulted hexacoordinate with the acetato groups acting as symmetrical chelates. The complexes [ZnbotSO 4 ] and [CdbotSO 4 ] have a linear structure with the sulphate group acting as unidentate with a C 3ν symmetry, polymeric structures with the sulphate anion functioning probably as chelate and of symmetry lower than C 2ν being excluded from the i.r. evidence. Allocation for the possible metal-ligand and metal-anion modes have also been made.

Preparation and nuclear magnetic resonance studies of stereochemically nonrigid magnesium, zinc, and cadmium derivatives of hexaborane(10). Crystal and molecular structure of bis(tetrahydrofuran)magnesium bis(nonahydrohexaborate)

Preparation and nuclear magnetic resonance studies of stereochemically nonrigid magnesium, zinc, and cadmium derivatives of hexaborane(10). Crystal and molecular structure of bis(tetrahydrofuran)magnesium bis(nonahydrohexaborate)

Isoxazole complexes. Complexes with copper(II), cobalt(II), nickel(II) and cadmium(II)

The preparation, spectral and magnetic properties of the complexes of copper(II), nickel(II), cobalt(II) and cadmium(II) with isoxazole are reported. Most of these compounds have distorted octahedral structures, whereas some, viz.: [Cu isox Cl 2] and [Co isox Br 2] are tetrahedral. All cadmium derivatives have a pseudo-tetrahedral halide-bridged structure.

Studies on metal hydroxy compounds. XI. Thermal analyses, decomposition kinetics, and infrared spectra of cadmium and zinc halide derivatives

The thermal analyses of Cd2(OH)3X type of basic halides reveal that the decomposition occurs via a two-step dehydroxylation pattern, yielding CdOHX as an intermediate product after the initial mode. These results suggest that Cd2(OH)3X is an addition compound of the hydroxide and the 1:1 hydroxy-halide, i.e. Cd(OH)2•CdOHX. Calorimetric measurements along with related enthalpy values for the decomposition reaction are given.The kinetics of thermal decomposition of the compounds are classified into two main groups: (i) two-dimensional contracting plate model equation and (ii) first-order rate law.The infrared spectral data of thirteen Cd and Zn basic halides in the frequency region 4000–250 cm−1 are presented with their assignments.

Metal thiolates as initiators for the polymerisation of alkylene sulphides

Thiolates of the general formula (XCH2·CH2·S)yM, where M = Zn or Cd, y= 1 or 2, and X is a group capable of co-ordinating to M, are efficient initiators of the polymerisation of episulphides (less so where M = Cu or Ag). These compounds are often soluble in the reaction system and in all cases the cadmium derivatives are the most effective. although they are less distinct compounds than the zinc analogues. Variation of the nature of X allows the reproducible preparation of polymers bearing a variety of end-groups.

Studies on metal hydroxy compounds. IV. Infrared spectra of cadmium derivatives Cd(OH)2, CdOHCl, and CdOHF

Infrared spectra of hexagonal Cd(OH)2, CdOHCl, and CdOHF, along with deuterated analogues CdODCl and CdODF, in the range 2.5–16 μ are reported for the first time. The effects of substituting a halogen for an OH group in Cd(OH)2 are (i) shift of OH stretching vibration to a lower frequency and (ii) appearance of strong absorption bands in the region 8–16 μ. All the observed bands in the deuterated analogues are displaced to lower frequencies with νH/νd ratios between 1.35–1.37. The spectra of CdOHCl and CdOHF show a high correlation with their zinc analogues and although both spectra appear consistent with a simple molecule of Cs or C1 symmetry, an alternate interpretation is given in terms of OH lattice vibrations.

Studies on metal hydroxy compounds. III. Thermal analyses of cadmium derivatives Cd(OH)2, CdOHCl, and CdOHF

Thermogravimetric and differential thermal analyses of Cd(OH)2, CdOHCl, and CdOHF are reported and discussed. The results show that the presence of a halogen substituent contributes to greater thermal stability of the hydroxy compound. The thermal stability increases in the order Cd(OH)2 < CdOHF ≤ CdOHCl, which is in contrast with the order of the zinc derivatives.The expected increase in the stability of the cadmium hydroxy compounds relative to the zinc hydroxy compounds was observed except for CdOHF. The exception of CdOHF is ascribed to its departure from the expected hexagonal structure and its existence in the orthorhombic form.The cadmium hydroxy compounds decompose via dehydration in the initial step, followed by hydrolysis and (or) volatilization of the cadmium halide to yield an ultimate residue of cadmium oxide.

Cadmium derivatives of decaborane

Diethylcadmium (Et2Cd) reacts with decaborane (B10H14) in ether solvents to form CdB10H12,2S (where S is diethyl ether or tetrahydrofuran). This compound is thought to be the first example of a neutral, 6,9-internally-bridged derivative of B10H14(2802 topology) and contains direct Cd–B bonds. The cadmium borane reacts quantitatively with ethereal hydrogen chloride to give decaborane and cadmium chloride, and ionises in aqueous solution to yield the novel dianion [(B10H12)2Cd]2–. The properties and structures of these compounds are discussed.