- Metal-sulphur Bond Enthalpy Determination of Di-n-Butyldithiocarbamate Chelates of Zinc, Cadmium and Mercury
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The standard molar enthalpies of formation of crystalline n2)2> (M = Zn, Cd or Hg), determined through reaction-solution calorimetry at 298.15 K, were found to be -471.23 +/- 3.90, -440.74 +/- 3.79 and -319.29 +/- 3.38 kJ mol-1, respectively.The corresponding molar enthalpies of sublimation, 107 +/- 3, 123 +/- 3 and 195 +/- 3 kJ mol-1, were estimated by means of differential scanning calorimetry.From the standard molar enthalpies of formation of the gaseous chelates, -364 +/- 5, 318 +/- 5 and -124 +/- 5 kJ mol-1, the homolytic and heterolytic mean metal-sulphur bond enthalpies were calculated.The homolytic enthalpies decrease from zinc to mercury, while the heterolytic values are almost constant.
- Souza, Antonio G. de,Souza, Jose H. de,Airoldi, Claudio
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- Ultrathin ZnS single crystal nanowires: Controlled synthesis and room-temperature ferromagnetism properties
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Highly uniform single crystal ultrathin ZnS nanowires (NWs) with 2 nm diameter and up to 10 μm length were fabricated using a catalyst-free colloidal chemistry strategy. The nanowires crystallized in hexagonal phase structure with preferential growth along the direction of the (001) basal plane. The strong polarity of the (001) plane composed of Zn cations or S anions drives the oriented attachment of ZnS nanocrystals (NCs) along this direction via electrostatic (or dipole) interaction. The ultrathin ZnS nanowires show intrinsic ferromagnetism at room temperature and other unusual properties related to its unique nature, such as large anisotropic lattice expansion, large blue-shift of UV-vis absorption band of the excition, and photoluminescence spectrum of the exciton band edge. First-principles DFT computation results show that Zn vacancies can induce intrinsic ferromagnetism in these undoped ZnS NWs. The main source of the magnetic moment arises from the unpaired 3p electrons at S sites surrounding the Zn vacancies carrying the magnetic moment ranging from 0.26 to 0.66 μB. Calculated results indicate that the magnetic moment of the ultrathin ZnS NWs can be increased by increasing the Zn vacancy concentration without significant energy cost. The calculated magnetization value (1.96 or 0.40 emu/g for Zn vacancies on the surface of NWs or inside, respectively) by Zn53S54 supercell model is larger than our experimental value (0.12 emu/g at 1.8 K and 0.05 emu/g at 300 K), but the ferromagnetic result is qualitatively in agreement.
- Zhu, Guoxing,Zhang, Shuguang,Xu, Zheng,Ma, Jing,Shen, Xiaoping
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- Controllable growth of semiconductor heterostructures mediated by bifunctional Ag2S nanocrystals as catalyst or source-host
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We demonstrate that Ag2S nanocrystals are the bifunctional mediator for controllable growth of semiconductor heterostructures including more complicated multisegments heterostructures in solution-phase, which is a new type of nanomediator and quite different from the metal nanoparticle catalyst. The intrinsic high Ag+ ion mobility makes Ag2S nanocrystals not only exhibit excellent catalytic function for growth of metal sulfide heterostructures but also act as a source-host for growth of ternary semiconductor heterostructures, for example, Ag2S-AgInS2. The semiconductors grow epitaxially from or inward in Ag2S nanocrystals forming single-crystalline heterostructures. Moreover, the method developed here also can construct multisegments heterostructures, for example, Ag2S-CdS-ZnS, AgInS2-Ag2S-AgInS2. The interfacial structure is still stable even if the lattice mismatch is quite large, which is a unique feature of this method.
- Zhu, Guoxing,Xu, Zheng
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- Method for preparing crystal form thioamino carboxylate by taking secondary amine as raw material
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The invention relates to a method for preparing crystal form thioamino carboxylate by taking secondary amine as a raw material, namely a method for preparing the crystal form thioamino carboxylate bya one-step method through a mixed reaction of the secondary amine, carbon disulfide, metal oxide or hydroxide in water. According to the scheme, conventional reaction equipment and simplified raw materials are used for preparing a high-purity product; the method is low in water consumption, inorganic salt byproducts are not generated, and the reaction mother liquor can be recycled directly or through simple treatment.
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Paragraph 0045-0046; 0059-0062
(2020/05/01)
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- Dibutyl dithiocarbamate acid zinc preparation method (by machine translation)
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The present invention relates to rubber vulcanization accelerator field, in particular, provides a dibutyl dithiocarbamate acid preparation method of zinc, to contain zinc oxide, two-butylamine, dispersant and 1st of the organic solvent in the reaction solution dropwise carbon disulfide reaction, after the reaction to obtain the dibutyl dithiocarbamate acid zinc, wherein the 1st organic solvent insoluble in water, and the resulting dibutyl dithiocarbamate acid zinc not soluble in or soluble in 1st organic solvent. The method adopts a non-water solvent method preparation dibutyl dithiocarbamate acid zinc, avoids the generation of salt-containing waste water, because the 1st organic solvent is insoluble in water, it can be with a minute fluid operation the two are separated, 1st organic solvent after removing water can be reused, reducing solvent cost while increasing the yield of the product. The above method is simple in operation, avoids the generation of salt-containing waste water, it is a clean environmental protection of the new method, the method is easily applied to large-scale production practice among them. (by machine translation)
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Paragraph 0056; 0057; 0062; 0063; 0067; 0068; 0072; 0073
(2018/07/15)
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- A pulse Polarographic method for the analysis of zinc dithiocarbamates
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An extremely sensitive pulse Polarographic method for the determination of zinc dimethyldithiocarbamate (an agricultural fungicide) and zinc di-n-pentyldithiocarbamate (a petroleum additive), has been developed based on the reaction of their dithiocarbamate moiety with copper(II) Perchlorate in acetonitrile medium. Well defined diffusion-controlled peaks are observed at -140 mV and -130 mV (vs SCE) for zinc dimethyldithiocarbamate and zinc di-n-pentyldithiocarbamate respectively. The peaks shows approximately four-fold higher sensitivity than that obtained by pulse polarography of the zinc dithiocarbamate alone. A linear relationship is obtained between concentration of the zinc dithiocarbamate [added to copper(II)] and peak current. Using cyclic voltammetry, a probable mechanism for the zinc dithiocarbamate-copper(II) reaction has been proposed.
- Sharma,Kumar, Satish,Chauhan, Chetan,Gupta, Atul
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p. 1121 - 1124
(2008/02/09)
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- Thermochemistry of adducts of zinc(II) dialkyldithiocarbamate with 2,2'-bipyridine
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The enthalpies of dissolution of adducts, Zn(II) dialkyldithiocarbamate and bipy, Zn(S2CNR2)2·C10H8N2, (R=C2H5, n-C3H7, n-C4H9, i-C4H9 and n-C5H11), in acetone were measured and the following thermochemical parameters for the adducts determined: The standard enthalpies for the Lewis acid/base reaction (Δ(r)Hθ), the standard enthalpies of formation (Δ(f)Hθ), the standard enthalpies of decomposition (Δ(D)Hθ), the lattice standard enthalpies (Δ(M)Hθ) and the standard enthalpies of the Lewis acid/base reactions in the gas phase (Δ(r)Hθ(g)). The mean standard enthalpies of the zinc-nitrogen bonds have been estimated and range from 54 to 138 kJ mol-1. The standard enthalpies of sublimation of the adducts were determined by differential scanning calorimetry and estimation methods. The thermodynamics of adduct formation between Zn(II) dialkyldithiocarbamate and bipyridine in acetone solution was determined by calorimetric titration. The results indicate the following order of the enthalpy changes for the interaction: EtPr(n)Pe(n)Bu(n)Bu(i). (C) 2000 Elsevier Science B.V.
- A. Imeida Sales, Jise Almir de,Souza, Antonio Gouveia,Freitas, Geraldo Fernando Goncal de,Prasad, Shiva,Fatima Severo Trindade, Maria de,et al.
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