Diethyldithiocarbamate Ions Research Articles

Study of Translocation of Stabilized NO Forms through Rat Skin using Electron Paramagnetic Resonance Method

We studied the effect of dinitrosyl-iron complexes with N-acetyl-L-cysteine as a thiol-containing ligand (DNIC-Acc) after transdermal administration to rats. Electron paramagnetic resonance spectroscopy with a lipophilic NO spin trap (a complex of iron and diethyldithiocarbamate ions) showed that DNIC-Acc administration significantly increased the total level of NO in the lung and liver tissues of the animal, which was accompanied by a slight decrease in the mean BP (<10%).

Optical and electrochemical characteristics of Ir(III) complexes with metalated 4-(4-bromophenyl)-2-methyl-1,3-thiazole and isocyanide, ethylenediamine, and diethyldithiocarbamate ligands

The influence of donor–acceptor properties of tert-butyl-, 2.6-dimethylphenyl-, and 4-bromophenyl-isocyanides (BuNC, XylNC, BpNC), ethylenediamine (En), and diethyldithiocarbamate ions (Dtc–) on the 1H and 13C NMR, IR, optical, and electrochemical characteristics of Ir(III) complexes with metalated 4-(4-bromophenyl)-2-methyl-1,3-thiazole is studied. Enhancement of the donor properties of BpNC, XylNC, BuNC, En, and Dtc– ligands leads to a bathochromic shift of metal-to-ligand charge transfer (MLCT) bands and to a decrease in the difference between the one-electron oxidation and reduction potentials of complexes. The bathochromic shift of the low-temperature phosphorescence of complexes in frozen (77 K) solutions with increasing donor properties of BpNC, XylNC, BuNC, En, and Dtc–ligands is caused by a decrease in the admixture of MLCT to the intraligand excited state of {Ir(bptz)2}. Quenching of the phosphorescence of complexes in liquid solutions is attributed to the thermally-induced population of excited d–d* states with subsequent nonradiative deactivation.

Determination of the Specific Heat Capacity of RE(Et2dtc)3(phen) by Microcalorimetry

Abstract A calculation formula for determining the specific heat capacity of solid compound with an improved RD496‐III microcalorimeter was derived. The calorimetric constant and precision determined by the Joule effect were (63.901±0.030) µV/mW and 0.3% at 298.15 K, respectively, and the total disequilibrium heat has been measured by the Peltier effect. The specific heat capacities of two standard substances (benchmark benzoic acid and α‐Al2O3) were obtained with this microcalorimeter, and the differences between their calculated values and literature values were less than 0.4%. Similarly, the specific heat capacities of thirteen solid complexes, RE(Et2dtc) 3(phen) (RE=La, Pr, Nd, SmLu, Et2dtc: diethyldithiocarbamate ion, phen:1,10‐phenanthroline) were gained, and their total deviations were within 1.0%. These values were plotted against the atomic numbers of rare‐earth, which presents tripartite effect, suggesting a certain amount of covalent character in the bond of RE3+ and ligands, according to Nephelauxetic effect of 4f electrons of rare earth ions.

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.

Structure and properties of mono- and heterometallic cadmium, zinc, and nickel complexes containing diethyldithiocarbamate ions and ethylenediamine molecules

The crystal structure of the mono- and heterometallic complexes [MEn3]L2 (M = Zn2+,M2+) and [MEn3 ][CdL3]2 (M = Cd2+, Zn2+, Ni2+) containing ethylenediamine (En) molecules and diethyldithio-carbamate ions (L = (C2H5)2NCS2−) is investigated. The three heterometallic complexes are isostructural; their structure consists of discrete mononuclear ions. In the [MEn3]2+ cation, the central M atom lies on the twofold axis; therefore, two of the three metallocycles MN2C2 of the [MEn3]2+ cation are independent. One of the two has a gosh-configuration. In the coordinated En molecules, the N-M-N chelate angles are 77.0 and 82.9‡ (M = Cd2+); 80.0 and 80.5‡ (M = Zn2+); 79.7 and 80.8‡ (M = Ni2+). The nitrogen atoms form a distorted octahedron around M. The average M-N bond lengths for the complexes are 2.35, 2.19, and 2.16 a for M = Cd2+, Zn2+, and Ni2+, respectively. All the atoms of the [CdL3]− complex anion are in the general position; the central atom coordinates three cyclic bidentate L− ligands. The S atoms form a distorted trigonal prism, where the S...S distances in the vertical edges are nearly the same in all the complexes (2.94(1)-3.00(2) a). It was shown by1H,14N, and113Cd NMR that the ionic complexes [ZnEn3]L2 and [CdEn3][CdL3]2 in solution are transformed into nonelectrolyte type mixed-ligand complexes.

Synthesis and crystal and molecular structure of mixed-ligand compounds Eu(S2CN(C2H5)2)3(2,2′-Bipy) and Eu(S2CN(C2H5)2)3(1,10-Phen)

Synthetic procedures were developed and X-ray diffraction analysis was performed for two mixed-ligand compounds of europium(III) with diethyldithiocarbamate ions and 2,2′-bipyridyl (2,2′-Bipy) or 1,10-phenanthroline (Phen): Eu(S2CN(C2H5)2)3(2,2′-Bipy) (I) and Eu(S2CN(C2H5)2)3Phen (II). The structures of the complexes consist of discrete monomer molecules; the coordination polyhedron of Eu (EuN2S6 is a node) is a distorted dodecahedron.

COPPER BINDING SITE IN SERUM AMINE OXIDASE TREATED WITH SODIUM DIETHYLDITHIOCARBAMATE

Abstract The structure of copper binding site in bovine serum amine oxidase (BSAO) treated with diethyldithiocarbamate ion(DDC) was discussed by comparing its absorption and electron spin resonance spectra with those of a model copper complex. The structure of the model complex, [Cu(2,2′-bipyridine)(DDC)]+, suggested that at least two nitrogen atoms are coordinated around the copper ion in the native BSAO. Some organic chromophore from which the pink color of BSAO stems was also observed as the difference of the absorption spectra in the region of 450 to 600 nm between BSAO-DDC and the model complex.

Diethyldithiocarbamate-sensitive electrode for the simultaneous determination of metals

An electrode sensitive for diethyldithiocarbamate ions (DDC) down to 10/sup -5/ M is prepared by precipitation of copper diethyldithiocarbamate and silver sulfide within a graphite rod. The electrode is used as a monitor for simultaneous titration of binary, tertiary, and quaternary metallic mixtures of Cu, Cd, Ni, Pb, V, Th, and Zn in 50 to 75% ethanol at pH 4 to 6 using NaDDC as a titrant. Stepwise titration curves with sharp end point breaks and results with an average recovery of 98.5% (mean standard deviation +- 0.4%) are obtained with as little as 50 ..mu..g/mL of all these metal ions. Application of the method to simultaneous determination of some major elements in five different copper-base alloys gives results which compare favorably with certified values.

The Kinetics and Mechanism of a Reaction in Which Ligand Substitution is Accompanied by a Spin-State Change: Observation of the Elusive Monodithiocarbamatonickel(II) Complex in Dimethyl Sulfoxide

In solutions in Me2SO containing low concentrations of diethyldithiocarbamate ion (dtc-) and very high concentrations of Ni(Me2SO)62+ ion, the hitherto undetected Ni(dtc)+ complex is kinetically stabilized and its electronic spectrum can be recorded. The mono complex is thermodynamically unstable and is converted into Ni(dtc)2 by two independent pathways, one involving direct reaction between Ni(dtc)+ and dtc-, the other being a dimerization reaction, 2Ni(dtc)+ → Ni2+ + Ni(dtc)2. Analysis of the mechanistic scheme Ni2+ + dtc ↔ Ni(dtc)2 Ni(dtc)+ + dtc- → Ni(dtc)2 2Ni(dtc)+ → Ni2+ + Ni(dtc)2 gives k1 = 3 × 103 l, mol-1 s-1, k-1 ≈ 0.01 s-1, k2 ≈ 4 × 105 l, mol-1 s-1 and k3 ≈ 1 × 103 l. mol-1 s-1. Coordinated dtc- exerts a significant labilizing effect on coordinated Me2SO molecules in Ni(dtc)+.

Voltammetric behaviour of uranyl-diethyldithiocarbamate complexes in aprotic medium

The polarographic investigation of the reaction between uranyl and diethyldithiocarbamate ions in DMSO evidentiates two prevailing complex species: UO 2(DEDTC) + and UO 2(DEDTC) − 3. The two species exhibit one reversible cathodic wave (E 1 2 = −0.662V and −1.170V, respectively) both involving the reaction of the uranyl complex to uranium(V) complex. The formation of one reversible well-shaped anodic wave in the presence of diethyldithiocarbamate ion, due to the formation of mercury(II) complexes, has been already reported; in the present case, however, also the UO 2(DEDTC) − 3 species gives an anodic wave associated with the following electrode process: ▪ Cyclic voltammetric tests suggest that the mentioned cathodic processes are to be considered quasi-reversible, while the anodic one, involving the ligand exchange between UO 2+ 2 and Hg 2+, is not reversible. The stability constants of UO 2+ 2 and Hg 2+, diethyldithiocarbamate complexes are also estimated.

Extractive radiometric titration as a method of checking the extraction of gold with diethyldithiocarbamates

The extraction of gold(III) by copper-, zinc-, and mercury diethyldithiocarbamates from acid medium was studied by means of extractive radiometric titration, using trichloromethane or benzene as the solvent. Two end-points corresponding to the molar ratios 1 Au∶1 DDC and 1 Au∶2 DDC were observed on the titration curve of trivalent gold when diethyldithiocarbamate ion (DDC) was used as the titrant. Two compounds are formed successively: $$Cl_2 Au^{III} DDC and \{ [Au^{III} (DDC)_2 ]^ + \cdot Cl^ - \} $$ . The first compound is completely extracted into trichloromethane or benzene; the extractibility of the second compound increases with increasing solvent polarity. Univalent gold forms only one compound with the diethyldithiocarbamate ion: AuDDC.

Interaction between Tetraethylthiuram Disulfide and the Sulfhydryl Groups of d-Amino Acid Oxidase and of Hemoglobin

Abstract Inhibition of the crystallized hog kidney flavoenzyme, d-amino acid oxidase, by tetraethylthiuram disulfide (disulfiram, TETD) has been found to involve the sulfhydryldisulfide exchange reaction; primary products of the interaction between oxidase and reagent are diethyldithiocarbamate ion and a derived protein carrying mixed disulfide linkages, each of which consists of an enzyme thiol sulfur atom linked to a diethyldithiocarbamyl residue. Evidence for this conclusion includes the following observations. One mole (taken as 105 g) of d-amino acid oxidase contains 6 to 8 immediately reactive sulfhydryl groups of a total of 12 such residues. The extent of of the oxidase is a linear function of the amount of TETD added; complete is attained with 6 to 8 mole eq of TETD. Studies with 35S-TETD reveal, in association with the inhibition, the liberation of 6 to 8 mole eq of diethyldithiocarbamate ion and the fixation to oxidase protein of 6 diethyldithiocarbamyl residues. If the native enzyme is denatured with detergent, 12 mole eq of diethyldithiocarbamate ion are produced directly. The disulfide character of TETD is requisite for its inhibitory action on d-amino acid oxidase. Related compounds without a disulfide bond, such as tetramethylthiuram monosulfide, do not inhibit the oxidase, whereas a variety of other disulfide reagents, including tetramethylthiuram disulfide, tetrathionate, oxidized glutathione, formamidine disulfide, and 5,5'-dithiobis-(2-nitrobenzoic acid) are inhibitors. The stoichiometry of reaction between 35S-TETD and human oxyhemoglobin, in both the native and the denatured state, was found to compare favorably with predictions based on the sulfhydryl character of the protein and a comparable sulfhydryl-disulfide exchange reaction. The of d-amino acid oxidase by TETD, acting as a sulfhydryl-characterizing reagent, is time-dependent and irreversible; there is an associated conformational change of the oxidase protein. Flavin adenine dinucleotide retards the inhibitory process, whereas GSH prevents, but does not reverse, the inhibition. The over-all inhibitory process conforms to the criteria set forth earlier for the selective inhibition of polysulfhydryl enzymes by sulfhydryl-characterizing reagents.

Polarography of the Bis-(diethylthiocarbamyl) Disulfide—Diethyldithiocarbamate Ion Oxidation—Reduction System1

Polarography of the Bis-(diethylthiocarbamyl) Disulfide—Diethyldithiocarbamate Ion Oxidation—Reduction System¹