Thermochemistry on coordination behavior of samaric chloride hydrate with diethylammonium diethyldithiocarbamate

The complex of samaric chloride lower hydrate with diethylammoniumdiethyldithiocarbamate (D-DDC) was synthesized conveniently in absolute alcohol and dry N_2atmosphere. The title complex was identified as Et_2NH_2[Sm(S_2CNEt_2)_4] by chemical and elementalanalyses, the bonding characteristics of which was characterized by IR. The enthalpies of solutionof samaric chloride hydrate and D-DDC in absolute alcohol at 298.15 K and the enthalpies change ofliquid-phase reaction of formation for Et_2NH_2[Sm(S_2CNEt_2)_4] at different temperatures weredetermined by mi-crocalorimetry. On the basis of experimental and calculated results, threethermodynamic parameters (the activation enthalpy, the activation entropy, and the activation freeenergy), the rate constant, and three kinetic parameters (the apparent activation energy, thepre-exponential constant, and the reaction order) of liquid phase reaction of formation wereobtained. The enthalpy change of the solid-phase title reaction at 298.15 K was calculated by athermochemical cycle.

Heterotetranuclear Cu_2~IPd_2~Ⅱ Complex with Bis(diphenylphosphino)methane and Diethyldithiocarbamate

Self-assembly between the building blocks of Pd(Et2dtc)2 (Et2dtc = diethyldithio- carbamate) and [Cu2(m-dppm)2(MeCN)2]2+ (dppm = bis(diphenylphosphino)methane) gave a new heterotetranuclear complex [Cu2Pd2(m-dppm)2(m-Et2dtc)2(m3-Et2dtc)2](ClO4)2H2O (C70H86Cl2Cu2- N4O9P4Pd2S8, Mr = 1932.56), and its crystal structure has been determined by X-ray crystallo- graphy. It crystallizes in triclinic, space group P with a = 11.9834(6), b = 12.5624(6), c = 14.5603(8) ? a = 101.393 (1), b = 103.300 (1), g = 96.310(1), V = 2063.2(2) 3, Z = 1, Dc = 1.544 g/cm3, m(MoKa) = 1336 cm-1 and F(000) = 978. The total and unique reflections are 8710 and 5400, respectively. The structure was refined to R = 0.0860 and wR = 0.1996 for 3914 observed reflections with I > 2s(I). The title complex consists of the cation [Cu2Pd2(m-dppm)2(m-Et2dtc)2(m3- Et2dtc)2]2+, anion ClO4- and solvate H2O. The Pd(Ⅱ) atoms are located at the approximately square-planar environments with PS3 donors and the Cu(I) atoms display distorted tetrahedral geometries.

Thermochemical Study of Coordination of Holmium Chloride Hydrate with Diethylammonium Diethyldithiocarbamate

The complex of holmium chloride hydrate with diethylammonium diethyldithiocarbamate(D-DDC) was synthesized via mixing their solutions in absolute alcohol under a dry N 2 atmosphere. The elemental and chemical analyses show that the complex has the general formula Et 2NH 2[Ho(S 2CNEt 2) 4]. It was also characterized by IR spectroscopy. The enthalpies of the dissolution of holmium chloride hydrate and D-DDC in absolute alcohol at 298.15 K, and the enthalpy changes of liquid-phase reactions of the formation of Et 2NH 2[Ho(S 2CNEt 2) 4] at different temperatures were determined by microcalorimetry. On the basis of experimental and calculated results, three thermodynamic parameters(the activation enthalpy, the activation entropy and the activation free energy), the rate constant and three kinetic parameters(the apparent activation energy, the pre-exponential constant and the reaction order) of the liquid-phase reaction of the complex formation were obtained. The enthalpy change of the solid-phase complex formation reaction at 298.15 K was calculated by means of a thermochemical cycle.

Electrode process of diethyldithiocarbamate on surface of pyrrhotite

The electrode process of diethyldithiocarbamate on the surface of pyrrhotite was studied using systematic electrochemical analysis, including cyclic voltammetry, chronopotentiometry and galvanostatic. Experimental results show that tetraethylthioram disulphide(TETD) is electrodeposited on pyrrhotite electrode surface in the presence of 1.0×10 -4 mol/L diethyldithiocarbamate when the electrode potential is higher than 0.25V. The electrochemical kinetics parameters of the electrode process of diethyldithiocarbamate on surface of pyrrhotite are calculated as follows: the exchange current density is 2.48μA/cm2, and the transmission coefficient is 0.46. The electrodeposition includes two steps electrochemical reaction. The first reaction is electrochemical adsorption of diethyldithiocarbamate ion, then the adsorbed ion associates with a diethyldithiocarbamate ion from the solution and forms tetraethylthioram disulphide on the surface of pyrrhotite.

FTIR spectroscopic study of electrochemical flotation of jamesonite-diethyldithiocarbamate system

The flotation behavior of jamesonite was investigated with sodium diethyldithiocarbamate(DDTC) as a collector. The results show that jamesonite has good floatability from pH 2 to pH 13. The flotation of jamesonite is also dependent on the pulp potential. The potential-pH range for jamesonite flotation is established. The FTIR spectroscopy analysis shows that the major adsorption product of sodium diethyldithiocarbamate on jamesonite is lead diethyldithiocarbamate. The intensity of the FTIR signals of metal diethyldithiocarbamate adsorption on jamesonite and the flotation response of jamesonite are correlated with the pulp potential.

DIETHYLDITHIOCARBAMATE MAY ENHANCE THE ANTITUMOR EFFECT OF ADRIAMYCIN NANOPARTICLE-LIPIODOL EMULSION

Objective: To studied the effect of Diethyldithiocarbamate (DDC) on the antitumor activity of adriamycin (ADM) nanoparticle-lipiodol emulsion. Methods: The SD rats bearing liver carcinoma were divided into six groups and treated by saline, adriamycin, adriamycin nanoparticle-lipiodol emulsion, adriamycin liposome-lipiodol emulsion, DDC plus adriamycin nanoparticle-lipiodol emulsion, DDC plus adriamycin liposome-lipiodol emulsion respectively. The volume of the tumors, tumor growth rate (G%) and life prolonging rate PL% in six groups were determined. Results: The values of the IC50 (μg/ml) of adriamycin were reduced from 18.40 to 0.74 for the resistant cells SGC7901/CVR, and from 4.00 to 0.32 for the sensitive cells SGC7901/WT by pretreating the tumor cells with DDC. The tumor growth rate (G%) and life prolonging rate PL% increased significantly (P<0.05) in the DDC pretreated groups than adriamycin nanoparticle-lipiodol or adriamycin liposome-lipiodol emulsion groups. Conclusion: The antitumor effect of adriamycin can be enhanced by inhibiting the superoxide dismutase (SOD) in tumor cells by DDC.

SYNTHESIS AND APPLICATION OF ANTIMONY N,N-DIETHYLDITHIOCARBAMATE

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Inhibition of nitrification in soil by metal diethyldithiocarbamates

Nitrification acts as a key process in determining fertilizer use efficiency by crops as well as nitrogen losses from soils. Metal dithiocarbamates in addition to their pesticidal properties can also inhibit biological oxidation of ammonium(nitrification) in soil. Metal [M=V(Ⅲ), Cr(Ⅲ), Mn(Ⅱ), Fe(Ⅲ), Ni(Ⅱ), Cu(Ⅱ), Zn(Ⅱ) and Co(Ⅱ)] diethyldithiocarbamates (DEDTC) were synthesized by the reaction of sodium diethyldithiocarbamate with metal chloride in dichloromethane/water mixture. These metal diethyldithiocarbamates were screened for their ability to inhibit nitrification at different concentrations(10 μg/g soil, 50 μg/g soil and 100 μg/g soil). With increasing concentration of the complex, capacity to retard nitrification increased but the extent of increase varied for different metals. At 100 μg/g soil, different complexes showed nitrification inhibition from 22 36% to 46 45%. Among the diethyldithiocarbamates tested, Zn(DEDTC) 2 proved to be the most effective nitrification inhibitor at 100 μg/g soil. Manganese, iron and chromium diethyldithiocarbamates also proved to be effective nitrification inhibitors than the others at 100 μg/g soil. The order of percent nitrification inhibition in soil by metal diethyldithiocarbamates was: Zn(Ⅱ) > Mn(Ⅱ) > Fe(Ⅲ) > Cr(Ⅲ) >V(Ⅲ) > Co(Ⅱ) > Ni(Ⅱ) > Cu(Ⅱ).

Effects of diethyldithiocarbamate on myelin basic protein expression in the rat lateral olfactory tract

BACKGROUND： Dithiocarbamates can cause demyelination of axons in the peripheral nervous system. Its derivate, diethyldithiocarbamate, is cytotoxic, and causes olfactory mucosal damage and atrophy of the olfactory bulb. However, it is still unclear whether the myelin sheath of the lateral olfactory tract is affected by diethyldithiocarbamate. OBJECTIVE： To investigate the effects of diethyldithiocarbamate on the myelin sheath of the rat lateral olfactory tract. This was done by examining changes in myelin basic protein expression after diethyldithiocarbamate treatment. DESIGN, TIME AND SETTING： A randomized, controlled, animal study was performed at the Laboratory of the Department of Human Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, China from July to November 2007. MATERIALS： A total of 72 Sprague Dawley rats were randomly assigned into a diethyldithiocarbamate group （n = 32）, a solvent control group （n = 32）, and a blank control group （n = 8）. The diethyldithiocarbamate and solvent control groups were separately divided into 3-d, 7-d, 14-d and 28-d survival subgroups, with eight rats in each. Diethyldithiocarbamate （Sigma, USA） and goat anti-myelin basic protein polyclonal antibody （Santa Cruz, USA） were used in this study. METHODS： Rats in the diethyldithiocarbamate and solvent control groups were subcutaneously injected with diethyldithiocarbamate （600 mg/kg） and 0.01 mol/L phosphate buffered saline （600 mg/kg） at the posterior neck, respectively. Rats in the blank control group received no treatment. MAIN OUTCOME MEASURES： Immunohistochemical staining and Western blot assay were used to measure myelin basic protein expression in the rat lateral olfactory tract. RESULTS： Following immunohistochemical staining, myelin basic protein was uniformly distributed in the rat lateral olfactory tract in the blank control and solvent control groups. Western blot assay showed 21.5, 18, 17 and 14 ku positive bands. No significant difference was found in myelin basic protein distribution and blot pattern, in the rat lateral olfactory tract, in the diethyldithiocarbamate group, following immunohistochemical staining and Western blot assay. Myelin basic protein expression gradually decreased at day 3, reached the lowest level at day 7, and gradually increased again at days 14 and 28. CONCLUSION： Demyelination is induced by diethyldithiocarbamate in the rat lateral olfactory tract in an early stage, followed by remyelination at later stages.

Synthesis, Structure and Transesterification of the Derivatives of β-Alkoxycarbonylethyltin Trichlorides with Diethyldithiocarbamate

The derivatives of β-alkoxycarbonylethyltin trichlorides with diethyldithiocarbamate,ROCOCH2CH2Sn(S2CNEt2)Cl2, were synthesized and characterized by the means of elemental analysis, IR, 1H NMR and X-ray single crystal diffraction. The structural features of the compounds were described, and the possible mechanism of transesterification for compound 2a was suggested.

Electrochemical flotation of diethyldithiocarbamate-pyrrhotite system

Using sodium diethyldithiocarbamate as a collector the flotation behavior of pyrrhotite was investigated. The relationship between potential and pH range for pyrrhotite flotation was established. The results show that the flotation of pyrrhotite is dependent on pulp potential at certain pH values. Pyrrhotite has good floatability from pH 2 to pH 12, and poor flotability at pH>12. Cyclic voltammetry and Fourier transform infrared spectrum analysis show that the major adsorption product of DDTC on pyrrhotite is tetraethylthiuram disulfide. The intensity of Fourier transform infrared signals of tetraethylthiuram disulfide adsorbed on pyrrhotite and the anode current of a pyrrhotite electrode and flotation response of pyrrhotite are correlated with pulp potentials.

Synthesis and Crystal Structure of a Dicopper(Ⅰ) Complex with Bis(diphenylphosphino)methane and Diethyldithiocarbamate

The title complex [Cu2(-dppm)2(-Et2dtc)](ClO4)EtOH0.25H2O (dppm = bis- (diphenylphosphino)methane, Et2dtc = diethyldithiocarbamate) has been synthesized and characterized by single-crystal X-ray diffraction analysis. The crystal structure is of monoclinic, space group C2/c with a = 42.587(1), b = 14.1653(4), c = 20.5649(5) ? = 105.945(1)? V =11928.6 3, C57H60.5ClCu2NO5.25P4S2, Mr = 1194.09, Z = 8, Dc = 1.330 g/cm3, (MoK) = 0.98 mm-1 and F(000) = 4948. A total of 15243 reflections were collected, of which 7322 were unique. The structure was refined to R = 0.0739 and wR = 0.1846 for 5135 observed reflections with I > 2(I). The crystal structure consists of the complex cation [Cu2(-dppm)2(-Et2dtc)]+, anion ClO4- and solvate H2O and EtOH, where the dinuclear Cu(Ⅰ) atoms are bridged doubly by two dppm ligands and singly by Et2dtc to give three five-membered rings. The Cu(Ⅰ) atom is in an approxi- mately trigonal-planar environment with the P2S chromophore. The short Cu贩稢u separation (2.7111 ? suggests the presence of metal-metal contact.

DDTC络合去除硫酸铝中铁工艺条件的优化

利用络合剂二乙基二硫代氨基甲酸钠(DDTC)去除含铁硫酸铝溶液中的铁,探讨了DDTC用量、溶液pH值、反应温度、反应时间等因素对除铁效率的影响。结果表明,在DDTC用量(以100mL含铁硫酸铝计)为0.88g、溶液pH值为2.5～3.0、室温反应5min时,铁去除率达94%,铁含量低于50×10-6。该法可用于高档纸张和高级织物等工业领域中含铁硫酸铝溶液的铁去除。

Zn-DDTC共沉淀预富集火焰原子吸收光谱法测定水中微量镍

探讨了以Zn DDTC为共沉淀载体,共沉淀富集水中微量镍的方法,用火焰原子吸收光谱法测定镍,提高了灵敏度,选择性高,操作简便,方法检出限为3.78μg·L-1,相对标准偏差为3 92%～6.47%,回收率为95.8%～103.0%,用于测定自来水和其水源水中微量镍,结果满意。

DDTC体系中黄铁矿电极过程动力学的研究

在pH值为 11 4的二乙基二硫代氨基甲酸钠 (DDTC)体系中 ,采用循环伏安电位扫描、恒电位阶跃和计时电位法研究了黄铁矿的电极过程。循环伏安曲线表明 ,当c(DDTC) =1× 10 - 4 mol L时 ,电极电位大于0 2V(SHE)以后 ,黄铁矿电极表面发生四乙基二硫化秋兰姆 (TETD或D2 )的电化学沉积并残留在电极表面 ;采用恒电位阶跃法可以确定反应电流密度 (i)与反应时间 (t)之间的关系式为i =(9 0 8× 10 - 5 + 4 77×10 - 3 t0 5 ) - 1 ,由此可以确定DDTC在黄铁矿电极表面的扩散系数D为 3 72× 10 - 6 cm2 s ,TETD在黄铁矿电极表面的吸附厚度可达 1 6 3个单分子层 ;计时电位法则确定了pH为 11 4时 ,吸附于黄铁矿电极表面的TETD的电化学动力学方程为 η =0 116 -0 0 6 4lg[1-(t τ) 0 5 ] ,电化学动力学参数确定为 :交换电流密度i0 =3 0 8μA cm2 ,反应电子数n =2 ,反应传递系数α =0 46 2。

金属(Ⅱ)-DDTC螯合物微粒的共振散射光谱研究及分析应用

对Co（Ⅱ）-DDTC、Cu（Ⅱ）-DDTC、Cd（Ⅱ）-DDTC、Pd（Ⅱ）-DDTC、N i（Ⅱ）-DDTC、Pb（Ⅱ）-DDTC、Fe（Ⅱ）-DDTC 7种螯合微粒体系的吸收光谱和共振散射光谱进行了研究.解释了纳米微粒共振散射效应和体系的呈色.在选定条件下,金属离子的浓度与共振散射强度（IRS）呈较好的线性关系.用共振散射检测痕量钴时,其线性范围为0.012-1.44μg/mL,检出限为0.001 2μg/mL.用于针剂维生素B12中钴的测定,结果满意.

吐温-80-DDTC胶束增溶吸光光度法测定饮料中微量铜

利用非离子表面活性剂的胶束增溶增敏作用，研究和建立了吐温-80-DDTC水相体系中直接测定饮料中Cu（Ⅱ）的方法。在表面活性剂吐温-80存在下，于pH10．0碱性介质中，Cu（Ⅱ）与铜试剂（DDTC）形成灵敏度高的棕黄色络合物。铜含量在0．028～4．70mg·L^-1范围内遵守比耳定律，表观摩尔吸光系数为1．32×10^3L·mol^-1·cm^-1，检出限为0．01mg·L^-1，相对标准偏差为1．04％～1．67％，回收率为96．1％～101．7％，测定结果与有机溶剂萃取法一致。

Na_2S-DDTC深度处理络合Ni高浓度电镀废水

对比选用有机巯基类高分子螯合剂(DDTC)、无机硫(Na_2S)和氢氧化钠(Na OH)作为电镀Ni的捕集剂,对模拟电镀废水中的络合Ni进行深度处理,重点考察了反应p H值、药剂投加量、反应时间以及絮凝剂种类等因素对Ni的去除效果的影响,并对去除机理进行了探究.结果表明:对于高浓度络合Ni模拟废水ρ(Ni)=300mg/L,在p H9.0,Na_2S与DDTC投加比为ρ(Na_2S)/ρ(DDTC)=10,其中ρ(Na_2S)=600mg/L,ρ(DDTC)=60mg/L,反应时间t=6.0min,PAM投加量1.0mg/L时,Ni_2+的残余浓度为0.064mg/L,低于0.1mg/L达到废水排放标准;此外对Na_2S-DDTC与Ni反应生成的沉淀的溶出试验表明,在自然状态下该沉渣具有较高的稳定性,不会形成二次污染;通过粒径分布统计分析以及SEM表面形态观察分析可知Na_2S-DDTC复配药剂对Ni的捕集作用主要为有絮凝-共沉淀的协同作用.通过本研究,可以为Na_2S-DDTC处理高浓度含络合Ni电镀废水工艺设计提供理论支持.

DDTC-MIBK络合萃取-火焰原子吸收光谱法测定水和矿渣中铬[Ⅵ]和铬[Ⅲ]

铬以三价和六价形式存在于环境污染物中,其毒性和生理行为与价态有很大关系。因此,建立一个不同价态铬的快速、灵敏的测定方法是十分必要的。本文拟定的方法是在pH-4条件下,用二乙胺硫代甲酸钠(DDTC)与甲基异丁基甲酮(MIBK)络合萃取铬(Ⅵ),用原子吸收光谱法测定。铬(Ⅲ)不干扰。然后以另一份样品,在硫酸介质中用过硫酸铵将铬(Ⅲ)氧化为铬(Ⅵ),测定总铬量。用差减法计算铬(Ⅲ)的含量。通过各项条件试验建立了适宜的测定方法。

乳化剂OP增敏DDTC光度法测定大豆中微量铜(Ⅱ)

利用乳化剂聚乙二醇辛基苯基醚（乳化剂OP）胶束对二乙基二硫代氨基甲酸钠（DDTC）与铜（Ⅱ）显色反应增溶、增敏作用,建立了分光光度法测定水相体系中微量铜（Ⅱ）的新方法.研究表明,在pH=10的介质中,铜（Ⅱ）与DDTC及乳化剂OP形成的络合物,λmax=454 nm,摩尔吸光系数ε=1.2×104,铜含量在0~2.8μg/mL范围内线性关系良好（R=0.999 7）.用该法测得大豆中的铜平均质量浓度为0.902μg/g,加标回收率为99.50%~100.80%,RSD为0.37%（n=6）,结果令人满意.