Bis Cadmium Research Articles

Study of photophysical properties of Cdq2 thin film

In this work, the morphological and optical properties of the cadmium (II) bis(8-hydroxyquinoline) (Cdq2) thin film are presented. The film was elaborated by physical deposition technique. The Atomic Force Microscopy (AFM) image shows a homogenous surface. The transmittance was measured in the range of 300–1200 nm with UV–visible spectroscopy. The emission of the film was characterized via the photoluminescence spectroscopy, a strong luminescence has been found. The measurements done at low temperatures show a decrease of the intensity of luminescence in the temperature range of 77–300 K.

Synthesis and structures of zinc and cadmium bis(dithiophosphonate) complexes

We report on the reaction between bis(dithiophosphonate) ligands of the type [NH4]2[S2P(1,4-C6H4OMe)(OCH2CH=CHCH2O)P(1,4-C6H4OMe)S2}] (L1) and the two common metal nitrates, Zn(NO3)2·6H2O and Cd(NO3)2·4H2O, in aqueous solution. The reaction led to interesting new dinuclear complexes of the type [M2{S2P(1,4-C6H4OMe)(OCH2CH=CHCH2O)P(1,4-C6H4OMe)S2}2] [M = Zn (1) and Cd (2)] in M:L molar ratio (1:1). Based on X-ray structural studies, each ligand is involved in two bonding modes to the metal center: bridging and chelating, and each complex contained a four, eight and eleven-membered metallacycle. This versatile but underutilized ligand type is potentially suitable for a variety of different bonding modes of new complexes to be discovered.

Multicomponent Self-Assembly of Metallo-Supramolecular Macrocycles and Cages through Dynamic Heteroleptic Terpyridine Complexation.

Spontaneous formation of the heteroleptic cadmium(II) bis(terpyridine) complex under ambient conditions can be achieved by a combination of 6,6''-di(2,6-dimethoxylphenyl)-substituted and unsubstituted terpyridine-based ligands. Building on this dynamic heteroleptic complexation, diverse metallo-supramolecular macrocycles and cages were readily assembled in quantitative yields from the predesigned multicomponent systems. The complementary ligation reinforced self-recognition to facilitate the shape-dependent self-sorting of a four-component dynamic library into two well-defined parallelograms. In addition, the subtle lability difference between homoleptic and heteroleptic complexes led to the site-selective CdII -ZnII transmetalation in the Sierpiński triangle. Facile construction of a dodecanuclear tetrahedral metallocage was also realized by using two self-recognizable tritopic building blocks. The photophysical study of the metallo-supramolecules assembled from the d10 metal ions revealed intense ligand-based photoluminescence in solution. The self-assembly strategy described here provides an efficient methodology for building pre-programmable, sophisticated supramolecular architectures furnished with photoactivity.

Cadmium Bis(phenyldithiocarbamate) as a Nanocrystal Shell-Growth Precursor.

Cadmium bis(phenyldithiocarbamate) [Cd(PTC)2] is prepared and structurally characterized. The compound crystallizes in the monoclinic space group P21/n. A one-dimensional polymeric structure is adopted in the solid state, having bridging PTC ligands and 6-coordinate pseudo-octahedral Cd atoms. The compound is soluble in DMSO, THF, and DMF and insoluble in EtOH, MeOH, CHCl3, CH2Cl2, and toluene. {CdSe[n-octylamine]0.53} quantum belts and Cd(PTC)2 react to deposit epitaxial CdS shells on the nanocrystals. With an excess of Cd(PTC)2, the resulting thick shells contain spiny CdS nodules grown in the Stranski-Krastanov mode. Stoichiometric control affords smooth, monolayer CdS shells. A base-catalyzed reaction pathway is elucidated for the conversion of Cd(PTC)2 to CdS, which includes phenylisothiocyanate and aniline as intermediates, and 1,3-diphenylthiourea as a final product.

Room-temperature solid-state synthesis and fluorescence performance of 8-hydroxyquinoline-based nanomaterial complexes with different morphology

Three main-chain 8-hydroxyquinoline-based metallocomplexes (aluminium(Ⅲ) tri-(8-hydroxyquinoline) (AlQ3), cadmium (Ⅱ) bis-(8-hydroxyquinoline) monohydrate (CdQ2·H2O), and magnesium(Ⅱ) bis-(8-hydroxyquinoline) tetrahydrate (MgQ2·4H2O)) nanomaterials were prepared by room-temperature solid-state reaction technique. The results of X-ray diffraction (XRD), elemental analyses (EA), fourier transform infrared (FTIR) spectroscopy and thermogravimetric/differential scanning calorimetry (TG/DSC) analysis demonstrated that the chemical composition of the products were AlQ3, CdQ2·H2O, and MgQ2·4H2O, respectively. The field emission scanning electron microscopy (FESEM) images and the transmission electron microscopy (TEM) images showed the morphology of AlQ3 nanoshuttles, CdQ2·H2O nanorods, and MgQ2·4H2O nanosheets, respectively. The UV–vis absorption spectra indicated that they existed charge transfer from the metal to the ligand (MLCT bands). The photoluminescence (PL) spectra revealed that three products displayed efficient and intense photoluminescence in yellow-green, deep-green and blue-green emissions region in the state of solid powder. PL intensity was weaker at different degree in chloroform, dimethylformamide, acetone and acetonitrile solutions, which attribute to solvate effect. The fluorescence quantum yields indicated that this metal complex materials can possibly act as functional composites to be used in optoelectronic devices, such as organic light-emitting diodes and fluorescent sensor.

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.

Synthesis and Surface Chemistry of Cadmium Carboxylate Passivated CdTe Nanocrystals from Cadmium bis(Phenyltellurolate)

We report the synthesis of cadmium telluride nanocrystals from cadmium bis(phenyltellurolate) (Cd(TePh)2) and cadmium alkylcarboxylates (Cd(O2CR)2, O2CR = oleate, tetradecanoate). Cd(TePh)2 reacts quantitatively with Cd(O2CR)2 at 220 °C over 1 h with the concomitant elimination of diphenyl telluride (Ph2Te) and CdTe nanocrystals. The nanocrystal diameter approaches 3.0–3.2 nm at full conversion regardless of changes to the solvent, carboxylate chain length, heating conditions, and reaction concentration. Larger nanocrystals may be grown by slow addition of additional precursors to the crude product mixture. Isolated nanocrystals have carboxylate ligands (2.1–4.7 nm–2) that can be displaced along with excess cadmium ions using low concentrations of N,N,N′,N′-tetramethylethylenediamine (TMEDA) (1.5–280 mM). Using 1H NMR spectroscopy, we measure the extent of the displacement and show that the binding of Cd(O2CR)2 to CdTe is weaker than to CdSe nanocrystals of similar size. The weaker binding is proposed to ...

Effect of Annealing Conditions in Hydrogen Atmosphere on Structural, Optical and Magnetic Properties of Nanocrystalline CdO Codoped with Cu and Co Ions for DMS Applications

Cadmium oxide powder codoped with Cu and Co ions (Cd0.94Cu0.01Co0.05O) was synthesised by thermal co-decomposition of a mixture of cadmium acetate dihydrate, bis(acetylacetonato)copper(II) and bis(acetylacetonato)cobalt(II) complexes. The purpose of the present investigation is to study the effect of H2-annealing conditions on the evolution of structure, optical and magnetic properties by varying temperature (300, 350 and 400 °C) and duration time (30 and 60 min). X-ray fluorescence (XRF) and X-ray diffraction (XRD) methods confirm the purity and the formation of single nanocrystalline phase of the as-prepared powder; thus, both Cu and Co ions were incorporated into CdO lattice, forming solid solutions. Magnetic measurements reveal that the as-prepared solid solution (SS) gained paramagnetic (PM) properties, although pure CdO itself is considered as diamagnetic (DM). The measured effective magnetic moment of doped Co2+ was 3.55 μB. Interestingly, it was found that the hydrogenation process could transform the properties of the SS into room-temperature ferromagnetic (RT-FM) only. For example, the coercivity (Hc), remanence (Mr) and saturation magnetisation (Ms) were 279 Oe, 0.187 emu/g and 1.739 emu/g, respectively for SS annealed in H2 gas at 350 °C for 30 min. Thus, the possibility of producing CdO with RT-FM was proved, where the magnetic characteristics were tailored by doping and post treatment under H2 gas, thereby a new potential candidate to be used as a dilute magnetic semiconductor (DMS). However, the real effect of H2 annealing on such drastic transformation in the magnetic behaviour needs some in-depth theoretical research work.

A New Wells-Dawson-based Organic-Inorganic Honeycomb Hybrid Compound with Cadmium Bis(2,2´-biimidazole) Spacers

A new Wells-Dawson-based organic-inorganic honeycomb hybrid compound, namely [Cd3(H2biim)6P2W18O62]·2H2O (1) (H2biim=2,2´-biimidazole), was hydrothermally synthesized by using a cadmium salt, the biimidazole ligand and the Wells-Dawson-type POM, and characterized by single-crystal X-ray diffraction, elemental analyses and IR spectroscopy. In compound 1, each polyoxoanion cluster [P2W18O62]6- is coordinated by six [Cd(H2biim)2]2+ subunits via six of its terminal oxygen atoms on two equatorial sites. Each [Cd(H2biim)2]2+ subunit links two adjacent polyoxoanions. Thus, the linking styles of the [P2W18O62]6- and [Cd(H2biim)2]2+ subunits induce a honeycomb-like layer. The electrochemical and photocatalytic properties of the title compound have been studied.

In situ growth of well-dispersed CdS nanocrystals in semiconducting polymers

A straight synthetic route to fabricate hybrid nanocomposite films of well-dispersed CdS nanocrystals (NCs) in poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) is reported. A soluble cadmium complex [Cd(SBz)2]2·MI, obtained by incorporating a Lewis base (1-methylimidazole, MI) on the cadmium bis(benzyl)thiol, is used as starting reagent in an in situ thermolytic process. CdS NCs with spherical shape nucleate and grow well below 200°C in a relatively short time (30 min). Photoluminescence spectroscopy measurements performed on CdS/MEH-PPV nanocomposites show that CdS photoluminescence peaks are totally quenched inside MEH-PPV, if compared to CdS/PMMA nanocomposites, as expected due to overlapping of the polymer absorption and CdS emission spectra. The CdS NCs are well-dispersed in size and homogeneously distributed within MEH-PPV matrix as proved by transmission electron microscopy. Nanocomposites with different precursor/polymer weight ratios were prepared in the range from 1:4 to 4:1. Highly dense materials, without NCs clustering, were obtained for a weight/weight ratio of 2:3 between precursor and polymer, making these nanocomposites particularly suitable for optoelectronic and solar energy conversion applications.

The structure and optical absorption of single source precursors for II-VI quantum dots

Starting from its measured structure, the electronic structures and optical absorptions of CdSe single source precursor, cadmium bis(diselenophosphinate) (CSP), have been studied by means of density functional theory calculations. In contrast to covalent bonding in ligand-free cadmium selenide, the Cd–Se bonds in CSP are featured by the coordination of the 4p electrons of Se atoms, resulting in low net charge on Cd and blue shifted electron transitions. The ligands not only stabilize the CdSe core but also affect the HOMO–LUMO transition. Computations were extended to the corresponding ZnSe and CdS complexes and came to similar conclusions.

Self-healing metallopolymers based on cadmium bis(terpyridine) complex containing polymer networks

The utilization of metal–ligand interactions within polymers generates materials which are of interest for several applications, including self-healing materials. In this work we use methacrylate copolymers containing terpyridine moieties in the side chain for the formation of self-healing metallopolymer networks. The materials were synthesized using the reversible addition–fragmentation chain transfer (RAFT) polymerization technique and subsequent crosslinking by the addition of a metal salt, here cadmium(II) salts, with different counter-ions. The influence of the counter-ions on the self-healing process within these structures was analyzed. The research resulted in a new polymeric material featuring a high (intrinsic) healing efficiency at relatively low temperatures (<75 °C).

Conclusive Growth of CdTe Nanorods by Solvothermal Decomposition Using Single Source Precursors

CdTe nanorods are synthesized by solvothermal decomposition, using single source molecular precursors (SSMP) cadmium (II), complex of bis-(aminopropyl telluride) (SSMP-I) and cadmium (II) bis-(isopropyl telluro) propane (SSMP-II) and quinoline as solvent at relatively low temperature (210°C). As synthesized nanomaterials are structurally characterized by XRD and SEM, SEM micrographs revealed formation of rod shapes structures whose dimensions change with the source precursor molecule. The average crystallite size estimated from XRD data is 29.78 and 28.94 nm respectively using Precursors I and II. The average size of nanorods is 1.237 μm and 0.15μm respectively, estimated from SEM micrographs. These are much larger than the average crystallite size estimated from XRD data. This is attributed to the agglomeration of nanocrystallites as quinoline is not a good capping agent.

The Importance of Nanocrystal Precursor Conversion Kinetics: Mechanism of the Reaction between Cadmium Carboxylate and Cadmium Bis(diphenyldithiophosphinate)

We describe the synthesis of cadmium bis(diphenyldithiophosphinate) (Cd(S(2)PPh(2))(2)) from secondary phosphine sulfides and its conversion to cadmium sulfide nanocrystals. Heating Cd(S(2)PPh(2))(2) and cadmium tetradecanoate (≥4 equiv) to 240 °C results in complete conversion of Cd(S(2)PPh(2))(2) to cadmium sulfide nanocrystals with tetradecanoate surface termination. The nanocrystals have a narrow size distribution (d = 3.8-4.1 nm, σ < 10%) that is evident from the line width of the lowest energy absorption feature (λ = 412-422 nm, fwhm = 0.17 eV) and display bright photoluminescence (PLQY(bandedge+trap) = 36%). Interestingly, the final diameter is insensitive to the reaction conditions, including the total concentration of precursors and initial cadmium to sulfur ratio. Monitoring the reaction with (31)P NMR, UV-visible, and infrared absorption spectroscopies shows that the production of cadmium diphenylphosphinate (Cd(O(2)PPh(2))(2)) and tetradecanoic anhydride co-products is coupled with the formation of cadmium sulfide. From these measurements we propose a balanced chemical equation for the conversion reaction and use it to optimize a synthesis that affords CdS nanocrystals in quantitative yield. In light of these results we discuss the importance of well-defined precursor reactivity to reproducible conversion kinetics and the synthesis of nanocrystals with unambiguous chemical composition.

ChemInform Abstract: Metal Tetrahydroborates and Tetrahydroborato Metalates. Part 17. Bonding in Cadmium Bis(tetrahydroborate), and the Reaction with Lithium Tetrahydroborate.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Tris(1,10-phenanthroline-κ2N,N′)cadmium(II) bis(perchlorate) 3.5-hydrate: a water chain stabilized by perchlorate anions

The title compound, [Cd(C(12)H(8)N(2))(3)](ClO(4))(2).3.5H(2)O, contains a cross-shaped one-dimensional channel along the c axis which encapsulates an ordered water chain. This water chain features a centrosymmetric cyclic water hexamer unit with a chair-like conformation. Neighbouring hexamers are linked by bridging water molecules. The host perchlorate anions recognize and stabilize the guest water chain via three kinds of hydrogen-bond patterns, leading to the formation of a complex one-dimensional {[(H(2)O)(7)(ClO(4))(4)](4-)}(n) anionic chain. One perchlorate acts as a single hydrogen-bond acceptor dangling on the chain, the second perchlorate on the chain serves as a double hydrogen-bond acceptor for only one water molecule to form an R(2)(2)(6) ring, where both entities lie on a twofold axis, while the third perchlorate, which also lies on a twofold axis, accepts two hydrogen bonds from two equivalent water molecules and is involved in the construction of an R(6)(5)(14) ring.

Cadmium bis(4-pyridylformyl)piperazine coordination polymers: layered nets and a novel 3,5-connected binodal lattice

Slow diffusion of aqueous solutions of cadmium salts with methanolic solutions of bis(4-pyridylformyl)piperazine (4-bpfp) generated crystalline coordination polymer phases whose dimensionality and topology are determined largely by the nature of the counteranion. [CdCl2(4-bpfp)]n (1) and [Cd(NO3)2(4-bpfp)]n (2) both possess 2-D coordination polymer layers via ligation of pyridyl nitrogen and amide carbonyl oxygen atoms. {[Cd(H2O)2(4-bpfp)](ClO4)2·4-bpfp·3H2O}n (3) forms similar layer motifs, but with unligated perchlorate anions and 4-bpfp molecules in the interlamellar regions. Use of the more basic sulfate anion produced {[Cd(SO4)(4-bpfp)(H2O)]·H2O}n (4), which has cadmium sulfate polymeric layers linked into a novel 3,5-connected binodal lattice with (4.62)(4.6683) topology by tethering 4-bpfp ligands. All species undergo blue-violet luminescence on exposure to ultraviolet light.

Cadmium bis(phenylselenolate) as a precursor for the synthesis of polymeric Cd(μ-Se)clusters: Crystal and molecular structures of [Cd 4(SePh) 7(PPh 3)X] n (X = Cl, Br)

The reaction of Cd(SePh) 2 with CdX 2 (X = Cl ( 1), Br ( 2)) in MeOH in the presence of PPh 3 at 130 °C under solvothermal conditions affords the products [Cd 4(SePh) 7(PPh 3)X] n , a one-dimensional assembly of adamantanoid [Cd 4(SePh) 6(PPh 3)X] clusters joined into a polymeric chain by μ-SePh bridges. Compounds 1 and 2 represent examples of extended one-dimensional chains of closed ME (M = metal, E = S, Se, Te) systems, whose importance is based not only on their properties, but by their possible use as precursor materials for design and development of new methodologies via a “bottom up” strategy to obtain different clusters from single components.

Tris(2,2′-bipyridine-κ2N,N′)cadmium(II) bis(perchlorate) hemihydrate

The asymmetric unit of the title compound, [Cd(C10H8N2)3](ClO4)2·0.5H2O, consists of one complex [Cd(bpy)3]2+ cation (bpy = 2,2′-bipyridine), two perchlorate anions and one water molecule with half-occupancy. The central cadmium(II) ion is bound to six N atoms from three bpy ligands in a distorted octa­hedral coordination, with Cd—N bond distances ranging from 2.304 (3) to 2.395 (2) Å.

Synthesis and X-ray Structures of Cadmium Coordination Polymers Based on New Pyridine−Carboxylate and Imidazole−Carboxylate Linkers

Three cadmium coordination polymers based on new pyridine−carboxylate and imidazole−carboxylate linkers were synthesized hydrothermally from appropriate cadmium(II) salts and the corresponding ester or benzonitrile precursor ligands. While cadmium bis[3-{3-(2-pyridin-4-yl-vinyl)-phenyl}-propenate] (1) adopts a three-dimensional polymeric network structure, both cadmium bis[3-{3-(2-pyridin-4-yl-vinyl)-phenyl}-propenate] (2) and cadmium-[4-(2-imidazolylvinyl)benzoate-acetate (3) adopt two-dimensional framework structures. In all three compounds, the carboxylate groups bridge the adjacent Cd centers to lead to centrosymmetric coordination networks. Crystal data for 1: monoclinic space group P21/c, a = 5.054(1), b = 8.327(2), c = 30.56(1) Å, β = 92.69(1)°, and Z = 2. Crystal data for 2: monoclinic space group P21/c, a = 5.249(3), b = 14.977(6), c = 15.755(9) Å, β = 94.57(2)°, and Z = 2. Crystal data for 3: orthorhombic space group Pbca, a = 18.799(2), b = 7.754(1), c = 19.174(3) Å and Z = 8.