Cadmium Dithiocarbamate Research Articles

Comparative study on the effect of precursors on the morphology and electronic properties of CdS nanoparticles.

Cadmium dithiocarbamate and cadmium ethyl xanthate complexes were synthesized and characterized by microanalysis, Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analyses. The complexes were employed as molecular precursors for the fabrication of CdS nanoparticles in hexadecylamine (HDA) and oleylamine (OLA) at a temperature of 250 °C. Spherical and oval shaped particles with sizes ranging from 9.93 ± 1.89 to 16.74 ± 2.78 nm were obtained in OLA while spherical, oval and rod shaped particles with sizes ranging from 9.40 ± 1.65 to 29.90 ± 5.32 nm were obtained in HDA. Optical properties of the nanoparticles showed blue shifts as compared to the bulk CdS, with the OLA capped nanoparticles slightly more blue shifted than the corresponding HDA capped nanoparticles. Results of crystallinity patterns revealed hexagonal phase of CdS.

A new structural motif for cadmium dithiocarbamates: crystal structures and Hirshfeld surface analyses of homoleptic zinc and cadmium morpholine dithiocarbamates

Abstract The crystal and molecular structures of two homoleptic morpholine-derived dithiocarbamates of zinc, binuclear {Zn[S2CN(CH2CH2)2O)2]2}2 (1), and cadmium, one-dimensional coordination polymer {Cd[S2CN(CH2CH2)2O)2]2}2 (2), are described. In 1, a centrosymmetric binuclear molecule is found as there are equal numbers of chelating and bidentate bridging dithiocarbamate ligands; weak transannular Zn···S interactions are found within the resultant eight-membered {···SCSZn}2 ring which has the form of a chair. The resultant 4+1 S5 donor set is highly distorted with the geometry tending towards a square-pyramid. By contrast, a square-planar geometry is found in centrosymmetric 2 defined by symmetrically chelating dithiocarbamate ligands. The presence of Cd···S secondary bonding in the crystal of 2 leads to a distorted 4+2 S6 octahedron and a linear coordination polymer, which is unprecedented in the structural chemistry of cadmium dithiocarbamates. The analyses of the Hirshfeld surfaces for 1 and 2 show the dominance of H···H, S···H/H···S and O···H/H···O contacts to the surface, i.e. contributing around 90 and 80%, respectively.

Influence of functionalities over polymer, trimer, dimer formation and optical properties of cadmium dithiocarbamates

Homoleptic cadmium(II) bis(dithiocarbamate) complexes having polymeric [Cd(L)2]∞ (L=C7H5O2CH2NCS2CH2C6H5 (L1), 1; C6H4NO2CH2NCS2CH2C4H3O (L2), 2; C6H4FCH2NCS2CH2C4H3O (L3), 3), trinuclear [Cd(L4)2]3 (L4=4-ClC6H4CH2NCS2CH2C4H3O, 4) and dinuclear [Cd(L5)2]2, (L5=3-ClC6H4CH2NCS2CH2C6H5, 5) structures have been synthesized and characterized by elemental analyses, spectroscopy (IR, 1H and 13C {1H} NMR and UV–Vis.) and their structures have been revealed by X-ray crystallography. In 1–3 the dithiocarbamate ligands are uniquely bonded to the Cd atoms in a μ2,κ2 S,S-chelating-bridging fashion, portraying 1D coordination polymeric structures in which the cadmium(II) ions adopt six coordinate distorted octahedral structures. In 4 the six dithiocarbamate ligands are spectacularly arranged about the Cd atoms resulting in a centrosymmetric trinuclear complex in which the central metal adopts an octahedral geometry and the terminal Cd atoms are in square pyramidal environments. Complex 5 has the well-established centrosymmetric dimeric structure in which the metal atoms have a five-coordinate trigonal bipyramidal geometry. Complexes 1–4 are rare examples of polymeric and trinuclear cadmium dithiocarbamate complexes. 1–5 show luminescent characteristics in solution and in the solid state arising from the metal perturbed intra-ligand charge transfer (ILCT) states. Their TG analyses show a single step decomposition with the formation of CdS nanoparticles, which have been examined by PXRD and HRTEM.

Influence of ligand environments on the structures and luminescence properties of homoleptic cadmium(ii) pyridyl functionalized dithiocarbamates

Novel homoleptic pyridyl-3(N) functionalised dithiocarbamate complexes having polymeric, [Cd(L)2] (L = L1, C5H4NCH2NCS2CH2C6H5 (1), L2, (C5H4NCH2)2NCS2 (2), L3, C5H4NCH2NCS2CH2C4H3O (3) and L4, C5H4NCH2NCS2CH2C4H3S (4)); dinuclear, [Cd(L)2]2 (L = L5, (C8H6NCH2NCS2CH2NC5H4) (5)) and trinuclear, [Cd(L6)2]3 (L6 = CH3C6H4CH2NCS2CH2C4H3O) (6)) structures have been synthesised and characterized by elemental analysis, IR, UV-vis, and 1H and 13C NMR spectroscopy and their structures have been elucidated by X-ray crystallography. In 1–4, the cadmium(II) ions are six-co-ordinate with two bidentate dithiocarbamate ligands (L1–L4) in an equatorial plane and axially bonded by Py(N) of the dithiocarbamate ligands on adjacent molecules, thus adopting a distorted octahedral geometry (CdS4N2) in 2-D polymeric structures. Complexes 1 and 2 are isomorphous and have similar structures to those of 3 and 4, although they differ significantly in architecture and topology. In 3 and 4, the metal atoms occupy centrosymmetric sites. In marked contrast to these polymeric structures, complex 5 derived from ligand L5 containing a bulky indolyl substituent proved to be a dinuclear complex. In 5, the metal atom has a square pyramidal geometry. As in 1–4, the dithiocarbamate ligand in 5 is uniquely bonded to the metal centres in a μ2,κ3-N,S,S bridging-chelating fashion. Ligand L6 containing furfuryl and tolulyl substituents yielded a spectacular centrosymmetric trinuclear complex 6 with the central metal atom in an octahedral environment and the two outer metal atoms in square pyramidal environments in which the dithiocarbamate ligands are bonded in a μ2,κ2-S,S chelating-bridging and S,S chelating manner within the same molecule. To the best of our knowledge, 1–4 and 5 and 6 are the first examples of 2-D coordination polymeric, dinuclear and trinuclear cadmium dithiocarbamates. All the complexes show bright luminescence emission in the solid state; the coordination polymers 1 and 2 are strongly luminescent.

Structural organization of dithiocarbamate heteropolynuclear gold(III)-cadmium complexes from X-ray crystallography and 113Cd MAS NMR spectroscopy data

We study the interaction of dialkyl substituted and cyclic cadmium dithiocarbamates with [AuCl4]− anions in 2M HCl medium. The state of the chemisorbents upon contact with AuCl3 solutions is controlled by 113Cd MAS NMR spectroscopy. The result of the heterogeneous reactions involving chemisorption binding of gold(III) from the solutions and partial ion exchange is the formation of heteropolynuclear gold(III)-cadmium complexes. The crystal and molecular structure of the acetone-solvated form of polymeric bis-(N,N-diethyldithiocarbamato-S,S′) gold(III) hexachlorodicadmate is identified by single-crystal XRD. The main structural moieties of the compound are complex [Au{S2CN(C2H5)2}2]+ cations and [Cd2Cl6]2− anions. The structural self-organization of the complex at the supramolecular level is attributed to the secondary Au…S bonds between neighboring isomeric complex gold(III) cations; the bonding results in the formation of linear polymer ([Au{S2CN(C2H5)2}2]+)n chains, with [Cd2Cl6]2− anions alternating to the right and left of the chains.

Synthesis and spectral studies on nitrogen donor adducts of bis(4-ethylpiperazinecarbodithioato-S,S′)M(II) (M = Zn, Cd) and use of adducts of cadmium dithiocarbamate for the preparation of cadmium sulfide

[M(4-epzdtc)2(py)], [M(4-epzdtc)2(1,10-phen)], and [M(4-epzdtc)2(2,2′-bipy)] (where M = Zn(II), Cd(II); 4-epzdtc− = 4-ethylpiperazinecarbodithioate) were synthesized and characterized by IR and NMR (1H, 13C, HSQC and HMBC) spectra. A single-crystal X-ray analysis was carried out for [Zn(4-epzdtc)2(py)]. The N13CS2 chemical shifts of [M(4-epzdtc)2] and its adducts follow the order: [M(4-epzdtc)2] (ca 202 ppm) < [M(4-epzdtc)2(py)] (ca 204 ppm) < [M(4-epzdtc)2(N,N)] (N,N = 1,10-phen, 2,2′-bipy) (ca 206 ppm), due to the change in coordination number. Single-crystal X-ray structural analysis of [Zn(4-epzdtc)2(py)] showed that zinc is five-coordinate with four sulfurs from dithiocarbamate and one nitrogen from pyridine. This complex adopts a geometry intermediate between the tetragonal pyramid (C4v) and trigonal bipyramid (D3h). [Cd(4-epzdtc)2] and its adducts were used as single source precursors for preparation of CdS. The as-prepared CdS was characterized by powder X-ray diffraction, UV-Vis absorption, and fluorescence spectroscopy. The UV-Vis absorption spectra of CdS particles indicate a blue shift in the absorption spectra due to the quantum size effect.

Synthesis of hexadecylamine capped CdS nanoparticles using heterocyclic cadmium dithiocarbamates as single source precursors

Heterocyclic cadmium dithiocarbamates, [Cd(S 2CNC 5H 10) 2] and [Cd(S 2CNC 9H 10) 2] were synthesized. The complexes were thermolysed in hexadecylamine (HDA) to give HDA capped CdS nanoparticles. A combination of close to spherical, rod, bipods and tripods was obtained by varying the reaction parameters such as precursor concentration and temperature. The optical properties and X-ray diffraction studies of the particles are also reported.

The Chemical State of Sulfur in Cadmium Dithiocarbamate

The chemical state of sulfur atoms in cadmium dithiocarbamate is analyzed. The cadmium dithiocarbamate molecule and its atomic and geometrical structural analog, tetramethylthiuram disulfide, are modeled by the semiempirical PM3 and ab initio DFT methods. The results are analyzed by transforming the coefficients of the calculated wave function to new basis functions associated with the local geometry of sulfur atoms. SK β X-ray emission spectra have been constructed and analyzed. It is shown that in cadmium dithiocarbamate the sulfur atoms are in the same chemical state.

A novel single source precursor route to self capping CdS quantum dots

The synthesis of CdS nanocrystals has been carried out from the thermolysis in a dynamic vacuum, between 150 and 300 °C, of the novel asymmetric cadmium dithiocarbamate [Cd{S2CNMe(C18H37)}2]; the particles ‘self cap’ during preparation; different size nanocrystals were synthesised, at different temperatures, and there was a change in phase from cubic to hexagonal CdS at a decomposition temperature of 300 °C.

Anionic halide and isothiocyanate adducts of zinc and cadmium dithiocarbamates

The mixed-ligand complexes [NEt4][Zn(S2CNMe2)2X](X = Cl, Br, or NCS) and [NR4][Cd(S2CNEt2)2X](R = Et, X = Cl, Br, or NCS; R = Bun, X = I) have been prepared by reaction of zinc and cadmium bis(dithiocarbamate) with the tetraalkylammonium salt of the halide or thiocyanate in acetone at room temperature. The single-crystal X-ray structures of [NEt4][Zn(S2CNMe2)2(NCS)]1 and [NEt4][Cd(S2CNEt2)2(NCS)]2 were determined: 1, monoclinic, space group P21/n, a= 9.447(1), b= 16.661(2), c= 15.807(1)A, β= 97.10(1)° and Z=4; 2, orthorhombic, space group P212121, a= 16.213(1), b= 17.501(2), c= 10.243(1)A and Z= 4. The central Zn and Cd atoms show distorted trigonal-bipyramidal co-ordination geometry with the thiocyanate N atom occupying an equatorial position and the dithiocarbamate ligands spanning one axial and one equatorial position each. The infrared and Raman spectra (2100–50 cm–1) of the complexes are discussed. The metal–sulfur stretching frequencies are assigned in the ranges 226–205 (Zn–S) and 203–145 cm–1(Cd–S), respectively.

Determination of ultra-trace amounts of cadmium in natural waters by the combination of a solvent extraction procedure and anodic stripping voltammetry

A method combining a solvent extraction procedure with anodic stripping voltammetry for the reliable determination of ultra-trace amounts of cadmium in natural waters is reported. The element is pre-concentrated as cadmium dithiocarbamate into Freon and subsequently back-extracted into an acidic aqueous medium for the voltammetric determination. The utilisation of the pre-concentration procedure prior to the determination substantially reduces the required plating time for the electrochemical technique and hence permits a considerable reduction in the over-all analysis time. The separation of the analyte from the bulk of the natural water matrix permits the direct determination of 0.1 µg l–1 of the element from a calibration graph, whereas for lower concentrations the use of the standard additions method is necessary for reliable determination. The minimum amount of cadmium that can be pre-concentrated and determined reliably by the voltammetric technique is 0.025 µg l–1. The application of the over-all approach to an NBS Standard Reference Water (fresh water) and local sea water samples was successful.

Reversible electrode processes involving multistep mechanisms for cadmium dithiocarbamates and diselenocarbamates at mercury electrodes

Resultats d'etudes par voltammetrie cyclique, polarographie et polarographie a impulsions differentielles, des reactions d'oxydation et de reduction electrochimique