High-yield synthesis of quantum-confined CdS nanorods using a new dimeric cadmium(II) complex of S-benzyldithiocarbazate as single-source molecular precursor

A convenient solvothermal single-source route has been developed for the bulk synthesis of CdS nanorods using new air stable dimeric cadmium(II) complex of S-benzyldithiocarbazate, [Cd(PhCH₂SC(S)NHNH₂)Cl₂]₂, at a relatively low temperature. The decomposition of the precursor was made by heating at 160 °C in hexamethylenediamine (HMDA) to give amine capped CdS nanocrystals having yield ca. 90%; nano-dimensional rods are clearly visible in transmission electron microscope (TEM). The nanorods have been further characterized by X-ray diffraction (XRD), energy dispersed X-ray spectroscopy (EDX), FTIR and optical measurements. The structure of precursor was also established by single crystal X-ray crystallography.     

Heteroleptic cadmium(II) complex, potential precursor for semiconducting CDS layers

Coordination compounds may be used as efficient precursors for fabrication of semiconducting layers. Thermal stability of such a potential precursor — [Cd{SSi(O-tBu)₃}(S₂CNEt₂)]₂ — was investigated (tBu means tert-butyl and Et means ethyl). The kinetic study was performed by means of different multi-heating rate methods: isoconversional (Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose and Friedmann) methods associated with the criterion of the independence of the activation parameters on the heating rate. The kinetic triplet of the non-isothermal decomposition of this Cd(II) complex was established.     

Synthesis,characterization and antimicrobial activity of a bidentate NS Schiff base of S-benzyl dithiocarbazate and its divalent complexes

The reaction of S-benzyl dithiocarbazate (SBDTC) with 2,4,5-trimethoxybenzaldehyde afforded a bidentate NS Schiff base 1 (benzyl-3-N-(2,4,5-trimethoxyphenylmethylenehydrazine carbodithioate), which on further reaction with M(II) (where M(II) = nickel(II), zinc(II), palladium(II) and copper(II)) in ethanol under reflux yielded bis-chelated inner complexes [ML₂] 2–5 with deprotonated L. The ligand and its complexes were characterized by physicochemical techniques, viz., molar conductance, magnetic susceptibility measurement, IR, NMR, UV–Vis and mass spectroscopic techniques. The crystal structures of 1 and 5 were also determined by single-crystal X-ray crystallography. The crystal structure analysis showed that the ligand exists in its thione tautomeric form. In the complexes, each of the two deprotonated ligands chelated the metal ions through the β-nitrogen and the thione sulfur forming five-membered rings. The copper(II) complex (5) exhibited a square-planar geometry, where the two N₂S₂ chromophores are arranged trans. All the compounds showed strong antibacterial activity against S.-β-hemolyticus, Klebsiella pneumoni, and Escherichia coli. The compounds also showed strong antifungal activity against Aspergillus fumigatus, Aspergillus niger, Aspergillus flavus, and Candida albicans with the exception of the palladium(II) complex (4) which showed no activity, while all the compounds showed no activity against Fusarium vasinfectum.     

Studies on nanocrystalline cadmium sulphide (CdS) thin films deposited by spray pyrolysis

Cadmium chalcogenides with appropriate band gap energy have been attracting a great deal of attention because of their potential applications in optoelectronic devices. CdS in the form of thin film is prepared at different substrate temperatures by a simple and inexpensive chemical spray pyrolysis technique. The as-deposited thin films have been characterized by XRD, SEM, EDAX and electrical resistivity measurement techniques. The XRD patterns show that the films are polycrystalline with hexagonal crystal structure irrespective of substrate temperature. SEM studies reveal that the grains are uniform with uneven spherically shaped, distributed over the entire surface of the substrates. Compositional analysis reveals that the material formed is stoichiometric at the optimized substrate temperature. The optical band gap energy is found to be 2.44 eV with direct allowed band-to-band transition for film deposited at 300°C. The electrical resistivity measurement shows that the films are semiconducting with a minimum resistivity for film deposited at 300°C. The thermoelectric power measurement shows that films exhibit n-type of conductivity.     

Synthesis and crystal structure of cadmium(II) complex with 2-pyrimidinecarboxamide

The complex [Cd(N₂H₃C₅ONH₂)₂(CH₃COO)₂] (I) was synthesized and its structure was determined. The crystals are monoclinic: space group C2/c, a = 14/416(1), b = 9.410(1), c = 13.708(1) Å, β = 113.82(1)°, V = 1701.0(1) ų, ρ(calcd.) = 1.862 g/cm³, Z = 4. The structure consists of individual complexes I united by the N-H…O hydrogen bonding system into supramolecular framework. The coordination sphere of the cadmium atom (on axis 2) involves two chelate pyrimidinecarboxamide ligands, which form five-membered chelate rings CdOCCN(Cd-N(2) 2.432(4), Cd-O(3) 2.388(4) Å), and two monodentate CH₃COO^? ions (Cd-O(1) 2.280(3) Å). The second O atom of the acetate group is involved in a weak contact with the Cd²⁺ ion (Cd-O 2.670(4) Å). With account for the latter two contacts, the coordination polyhedron of Cd is irregular octahedron.     

Five-coordinate platinum(IV) complex as a precursor to a novel Pt(II) olefin hydride complex for alkane activation

The five-coordinate platinum(IV) complex (nacnac)PtMe3 (nacnac- = [{(o-iPr2C6H3)NC(CH3)}2CH]-) thermally eliminates ethane and methane to produce a novel olefin(hydrido)platinum(II) complex, where the olefin is part of the nacnac-type ligand. This Pt(II) product activates hydrocarbons, including alkanes under mild conditions, as indicated by scrambling of hydrogen and deuterium between the hydrocarbon solvent and selected positions on the ligand of the platinum complex. A mechanism in which olefin insertion into the metal hydride bond opens a site to allow hydrocarbon coordination and C-H bond oxidative addition is proposed.     

Synthesis of a new stable, neutral organothulium(II) complex by reduction of a thulium(III) precursor

The new stable, neutral Tm(II) complex (Cp(ttt))2Tm [Cp(ttt) = 1,2,4-tris(tert-butyl)cyclopentadienyl] can be obtained either by direct reaction of NaCp(ttt) with TmI2 or by reduction of (Cp(ttt))2TmI in non-polar solvents; this latter route may prove itself useful for the isolation of other neutral non-classical low-valent organolanthanide species.     

Synthesis and spectroscopic and structural studies of a new cadmium(II)-citrate aqueous complex. Potential relevance to cadmium(II)-citrate speciation and links to cadmium toxicity

The presence of cadmium in the environment undoubtedly contributes to an increased risk of exposure and ultimate toxic influence on humans. In an effort to comprehend the chemical and biological interactions of Cd(II) with physiological ligands, like citric acid, we explored the requisite aqueous chemistry, which afforded the first aqueous Cd(II)-citrate complex [Cd(C(6)H(6)O(7))(H(2)O)](n)() (1). Compound 1 was characterized by elemental analysis, and spectroscopically by FT-IR and (113)Cd MAS NMR. Compound 1 crystallizes in the orthorhombic space group P2(1)2(1)2(1), with a = 6.166(2) A, b = 10.508(3) A, c = 13.599(5) A, V = 881.2(5) A(3), and Z = 4. The X-ray structure of 1 reveals the presence of octahedral Cd(II) ions bound to citrate ligands in a molecular crystal lattice. Citrate acts as a tridentate binder promoting coordination to one Cd(II) through the central alcoholic moiety, one terminal carboxylate group, and the central carboxylate group. In addition, the central carboxylate binds to three Cd(II) ions. Specifically, one of the oxygens of the central carboxylate serves as a bridge to two neighboring Cd(II) ions, while the other oxygen binds to a third Cd(II). A bound water molecule completes the coordination requirements of Cd(II). (113)Cd MAS NMR studies project the spectroscopic signature of the nature of the coordination environment around Cd(II) in 1, thus corroborating the X-ray findings. Collectively, the data at hand are in line with past solution studies. The latter predict that other similar low molecular mass Cd(II)-citrate complexes may exist in the acidic pH region, thus influencing the uptake of cadmium by living (micro)organisms, their ability to metabolize organic substrates, and possibly Cd(II) toxicity.     

Synthesis and spectral studies of cadmium(II) complexes derived from di-2-pyridyl ketone and N-phenylsemicarbazide: First structural report of a cadmium(II) complex of semicarbazone

A new semicarbazone (HL) based on di-2-pyridyl ketone and its three cadmium(II) complexes [CdL(CH₃COO)]₂ · 2CH₃OH (1), Cd(HL)Br₂ (2) and [Cd₂L₂N₃]₂ · H₂O (3) were synthesized and characterized by different physicochemical techniques. The complex, [CdL(CH₃COO)]₂ · 2CH₃OH (1) is having a dimeric structure. In complexes 1 and 3, the ligand moieties are coordinated as monoanionic (L⁻) forms and in complex 2, the ligand is coordinated as neutral (HL) one. The coordination geometry around cadmium(II) in 1 is distorted octahedral, as obtained by X-ray diffraction studies.     

Thermolysis preparation of cadmium(II) oxide nanoparticles from a new three-dimensional cadmium(II) supramolecular compound

The reaction of cadmium(II) chloride and 4-pyridine carboxylic acid (4-Hpyc) produces a new threedimensional supramolecular compound [Cd(4-pyc)₂(H₂O)4] _n (1). Compound 1 is characterized by IR spectroscopy and elemental analyses. The single crystal X-ray data show an infinite three-dimensional structure formed by the hydrogen bonding and π-π stacking interactions. The CdO nanoparticles are obtained by direct calcination at 400°C, 500°C and 600°C in the air atmosphere as well as by thermolysis in oleic acid at 200°C. The obtained cadmium(II) oxide nanoparticles are characterized by X-ray diffraction and scanning electron microscopy. This study demonstrates another potential application of cadmium(II) supramolecular compounds in the preparation of nanoscale cadmium(II) oxide materials with a specific size and morphologies.     

Template synthesis of a rare 14-membered macrocyclic complex using cadmium(II) ion as a collector

Journal of Inclusion Phenomena and Macrocyclic Chemistry - In this work, a new macrocyclic cadmium complex, [Cd(ACE)I]2[CdI4] (1); ACE: 1,3,6,10,12,15-hexaazatricyclo[13.3.1.16,10]eicosane, was...     

Thermal decomposition of [bis(salicylaldehydato)cadmium(II)] to CdS nanocrystals

The present investigation reports, the novel synthesis of nanocrystals CdS using thermal decomposition of [bis(salicylaldehydato)cadmium(II)], as a new precursor, and elemental sulfur in oleylamine. The as-synthesized CdS crystals have diameters about 10 nm. The products were characterized by X-ray diffraction (XRD) transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) spectroscopy and Fourier transformed infrared (FT-IR) spectra. The results of this paper show that the shape and size of cadmium sulfide nanocrystals can be controlled systematically by adjusting certain reaction parameters, such as the reactant concentration, the reaction temperature and the reaction time. Cadmium sulfide nanoparticles and nanorods with different lengths have been successfully prepared.     

Synthesis and spectral characterization of zinc(II) and cadmium(II) complexes of acetone-N(4)-phenylsemicarbazone: Crystal structures of acetone-N(4)-phenylsemicarbazone and a cadmium(II) complex

Seven Zn(II) and Cd(II) complexes of ON donor acetone-N(4)-phenylsemicarbazone (HL) have been synthesized and physico-chemically characterized by partial elemental analyses, molar conductance measurements, infrared, electronic and ¹H NMR spectral studies. The semicarbazone binds the metal as a neutral bidentate ligand in all the complexes. The crystal structures of acetone-N(4)-phenylsemicarbazone and [Cd(HL)₂Cl₂] have been determined by X-ray diffraction studies. The coordination geometry around cadmium(II) in the complex [Cd(HL)₂Cl₂] is distorted octahedral.     

Fixation of atmospheric carbon dioxide by a cadmium(II) macrocyclic complex

A crystal structure showing an unusual trinuclear Cd(II) cluster bridged in mu3 fashion by a carbonate ligand is reported. The carbonate ion is formed by fixation of atmospheric carbon dioxide from the corresponding cadmium mononuclear complex containing an aza crown ether.     

Dinuclear cadmium (II) Schiff base complex: synthesis,crystal structure,spectroscopic characterization and application as a new precursor for preparation of nano-cadmium oxide

A novel cadmium (II) nano-complex, [Cd(EtOH)(HL)(NO₃)]₂ (1), (H₂L = 2-[(2-hydroxy-propylimino) methyl] phenol) was synthesized by solvothermal and sonochemical methods. The new nanostructure was characterized by scanning electron microscopy (SEM), X-ray powder diffraction, Fourier transform infrared spectroscopy and UV–Vis spectroscopy. Single crystalline of compound 1 was obtained using a branch tube method. The determination of the structure by single-crystal X-ray crystallography shows that the complex is a centrosymmetric dimer in which deprotonated phenolates bridge the two seven-coordinate metal atoms and link the two halves of the dimer. The luminescent properties of the complex 1 were examined and compared with the free ligand. The thermal stability of nano-complex 1 was analyzed by thermal gravimetric analysis. Furthermore, the effect of the initial substrates concentration on size and morphology of compound 1 nanostructure was investigated in sonochemical method. After the solid-state transformation of compound 1 at 650 °C in air, pure-phase nano-sized cadmium (II) oxide was produced. The morphology and size of the prepared CdO samples were further observed using TEM and SEM. Investigation of the optical properties of the produced cadmium oxide, using UV–Vis spectroscopy, confirmed its semiconducting properties by revealing optical band gap at 2.93 eV. A blue shift is observed in the band gap when compared with bulk sample which is due to the quantum size effect.     

CS‐Fe(II,III) complex as precursor for magnetite nanocrystal

Chitosan‐iron ions complex (CS‐Fe(II,III) complex) was used as precursor to synthesize magnetite nanocrystals and the mechanism was discussed. The magnetite nanocrystals have diameters of about 10 nm and clusters were formed due to slight aggregation of several magnetite nanocrystals. FT‐IR and X‐ray photoelectron spectrometer (XPS) investigations indicated that the Fe(II) and Fe(III) were chelated by ? NH₂ and ? OH groups of chitosan in CS‐Fe(II,III) complex, and the molar ratio of ? NH₂/Fe(II,III) was approximately 2. This chelation effect destroyed the hydrogen bonds of chitosan. In the following alkali treatment process, the chelated Fe(II) and Fe(III) provided nucleation site and formed the magnetite nanocrystals. After alkali treatment, the chelation effect between iron ions and ? NH₂ groups disappeared and some kind of weak interaction formed between magnetite and ? NH₂ groups. Moreover, the ? OH groups of chitosan have an interaction with the synthesized magnetite nanocrystals. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis of a platinum(II) complex of chloroanilic acid

Conclusions A platinum(II) complex of chloroanilic acid was synthesized. This complex is isostructural to the analogous palladium complex and has the formula [Pt(C₆O₄Cl₂)Cl₂]K₂'H₂O.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2123–2124, September, 1986.The authors thank O. N. Krasochka for a preliminary x-ray diffraction analysis of this complex.