Nickel(II) di(pentyl)dithiocarbamates with P ligands

Ni(II) di(pentyl)dithiocarbamates of composition [Ni(Pe₂dtc)₂], [NiX(Pe₂dtc)(PPh₃)] (X = Cl, Br, I, NCS), [Ni(NCS)(Pe₂dtc)(PBut₃)], [Ni(Pe₂dtc)(PPh₃)₂]ClO₄ and [Ni(Pe₂dtc)(PPh₃)₂]PF₆ (Pe₂dtc = di(pentyl)dithio-carbamate, PPh₃ = triphenylphosphine, PBut₃ = tributylphosphine) have been synthesized. The complexes have been characterized by the usual methods. X-ray structure analyses confirmed the nature of [NiI(Pe₂dtc)(PPh₃)] and [Ni(Pe₂dtc)(PPh₃)₂]ClO₄ complexes.     

μ-Oxo-bis[trimethylantion(V)] – Derivate von Dithiocarbamin-, Xanthogen-und Dithiophorsäuren

μ-Oxy-bis[trimethylantiomony(V)] Derivatives of Dithiocarbaminic-, Xanthogenic-, and Dithiophoric Acids u-Oxy-bis[trimethylantimony(V)] derivatives of the type [Me₃SbL]₂O (L = S₂CNR₂, S₂COR, S₂P(OR)₂) are obtained by the reaction of [Me₃SbBr]₂O with sodium dithiocarbamtes, xanthogentates and dithiophosphates. The products are characterized by elementary analysis molecular weight determination, IR, ¹H-NMR, and ¹³C-NMR spectroscopy.     

Über Chalkogenolate. 201. Untersuchungen über Selenformamide

On Chalcogenolates. 201 Studies on Selenoformamides The yellow selenoformamides H? CSe? NH₂, H? CSe? NH? CH₃, and H? CSe? N(CH₃)₂ have been prepared by reaction of the corresponding formamide with P₂Se₅. The compounds have been characterized by means of electron absorption, infrared, and nuclear magnetic resonance spectra. The decomposition of the selenoformamides in ethanolic solution has been studied kinetically at 20.0°C. The preparation of selenoformyl dithiocarbamates was not successful.     

Fullerene complexes with divalent metal dithiocarbamates: structures,magnetic properties,and photoconductivity

A series of complexes of fullerenes C₆₀ and C₇₀ with metal dithiocarbamates {M^II(R₂dtc)₂}·C_m (m = 60 or 70) and metal dithiocarbamates coordinated to nitrogen-containing ligands (L), {M^II(R₂dtc)₂)_x·L}·C₆₀ (x = 1 or 2), where M = Cu, Zn, Cd, Hg, Mn, or Fe, R = Me, Et, Prⁿ, Prⁱ, or Buⁿ, L is 1,4-diazabicyclo[2.2.2]octane (DABCO), N,N′-dimethylpiperazine, or hexamethylenetetramine, were synthesized. The shape of dithiocarbamate molecules is sterically compatible with the spherical shape of C₆₀, resulting in an efficient interaction between their π systems. The resulting compounds are characterized by a layered or three-dimensional packing of the fullerene molecules. In the C₆₀ complexes, iron(II) and manganese(II) dithiocarbamates exist in the high-spin states (S = 2 and 5/2). The magnetic susceptibility of {M^II(Et₂dtc)₂}₂·C_m (M = Fe or Mn, m = 60 or 70) in the temperature range of 200–300 K is described by the Curie-Weiss law with Θ = −250 and −96 K and with maxima at 110 and 46 K, respectively, which is indicative of a strong antiferromagnetic spin coupling between M^II. The Weiss constants for the [{M^II(Et₂dtc)₂}₂·DABCO]·C₆₀·(DABCO)₂ complexes (M = Fe or Mn) are 1.7 and 0.3 K, respectively. The magnetic moments of the complexes containing Fe and Mn dithiocarbamates slightly increase at temperatures below 50 and 35 K, respectively, which is evidence of the ferromagnetic spin coupling between M^II in {M^II(Et₂dtc)₂}₂·DABCO. Single crystals of the complexes exhibit low dark conductivity (10⁻¹⁰–10⁻¹¹ S cm⁻¹). The visible light irradiation of these crystals leads to an increase in the photocurrent by two–three orders of magnitude. The photogeneration of free charge carriers in the complexes occurs both due to the photoexcitation of metal dithiocarbamate (Cu^II(Et₂dtc)₂) and through the charge transfer from metal dithiocarbamate (M^II(Et₂dtc)₂, M = Zn or Cd) to C₆₀. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2072–2087, November, 2007.     

Interaction of Methyl N-(3-oxoalkyl)carbamates, S-methyl -Carbamates, and -Dithiocarbamates with Sodium Borohydride. Synthesis of Tetrahydro-1,3-oxazin-2-ones and -thiones

The interaction of N-(3-oxoalkyl)carbamates, -thiocarbamates, and -dithiocarbamates with sodium borohydride has been studied. It was shown that reaction proceeds diastereoselectively, and reductive cyclization with the formation of tetrahydro-1,3-oxazin-2-ones and -thiones may occur. The tend to cyclization of the N-(3-hydroxyalkyl)carbamates, -thiocarbamates, and -dithiocarbamates formed as intermediates depends on the number of substituents in the alkyl chain.     

Thiocarbamoylation of amine-containing compounds

Thiocarbamoylation of aliphatic amines with tetramethylthiuram disulfide (TMTD) was studied. The reactions were established to proceed according to a two-stage mechanism. In the first stage,S-(thiocarbamoyl)thiohydroxylamines and dimethyl dithiocarbamates are formed. The latter exist in equilibrium with dimethyldithiocarbamic acid, which can undergo decomposition to give dimethylamine and carbon disulfide. In the second stage, several competitive transformations of these intermediates into the final products occur,viz., (1) the reactions of CS₂ with primary amines on heating (70–110 °C) yield mixed and symmetrical thioureas and the reactions of CS₂ with secondary amines give symmetrical dithiocarbamates, and (2) insertion of CS₂ intoS-(thiocarbamoyl)thiohydroxylamines affords thiuram disulfides. Thiuram disulfides formed from primary amines decompose to give isothiocyanates, which are converted into thioureas by condensation with amines, whereas thiuram disulfides which are obtained in the reactions with secondary amines and which cannot form thioureas react with amines analogously to TMTD. For Part 4, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 334–342, February, 2000.     

Useful and accessible organometallic precursors for preparation of zinc sulfide and indium sulfide thin films via solution pyrolysis (printing) method

Polycrystalline β-zinc sulfide thin films were prepared by solution pyrolysis of an ethylzinc isopropylthiolate–zinc bis(dibutyldithiocarbamate) combined precursor (EtZnSiPr–Zn(S₂CNnBu₂)₂) in chloroform solution on glass or silicon(111) substrates at 300°C. Homogeneous but amorphous indium sulfide thin films were obtained from butylindium bis(isopropylthiolate) (nBuInSiPr₂) in P-xylene on these substrates at 300°C similarly. The sulfide thin films obtained were characterized by means of X-ray photoelectron spectroscopy (XPS), X-ray fluorescence Microanalysis, scanning electron microscopy (SEM) and optical band gap measurements.     

Determination of dithiocarbamates; improvements to the method described in EN 12396-1 standard

A procedure to improve the performance and reliability of the method described in European standard EN-12396-1 is presented. A CS₂ working range of 10–50 µg per 25 mL was validated. The quantification limit was lowered from 0.25 mg kg^?1 to 0.05 mg kg^?1 (200 g of sample matrix), in agreement with the Maximum Residue Limits for dithiocarbamates (DTCs). The procedure involves the measurement of the average absorbance at 374 nm and 435 nm, to allow for the equilibrium between the two coloured Cupric(II) complexes formed. Two main modifications of the decomposition and distillation apparatus assembly were introduced. One was the stabilization of the colour-forming reagent solution at 0°C to ensure stability of absorbance. The other was the inclusion of a bubbler trap with ethanol, to retain interfering compounds. The possible CS₂ contamination by several types of protective gloves was also studied. Vinyl gloves, made according to the AQL 1.5 – EN 455-1/2 standard, did not interfere with the method.     

Insights into the Reactivity of Gold–Dithiocarbamato Anticancer Agents toward Model Biomolecules by Using Multinuclear NMR Spectroscopy

Some gold(III)–dithiocarbamato derivatives of either single amino acids or oligopeptides have shown promise as potential anticancer agents, but their capability to interact with biologically relevant macromolecules is still poorly understood. We investigated the affinity of the representative complex [Au^IIIBr₂(dtc‐Sar‐OCH₃)] (dtc: dithiocarbamate; Sar: sarcosine (N‐methylglycine)) with selected model molecules for histidine‐, methionine‐, and cysteine‐rich proteins (that is, 1‐methylimidazole, dimethylsulfide, and N‐acetyl‐L ‐cysteine, respectively). In particular, detailed mono‐ and multinuclear NMR studies, in combination with multiple ¹³C/¹⁵N enrichments, allowed interactions to be followed over time and indicated somewhat unexpected reaction pathways. Whereas dimethylsulfide proved to be unreactive, a sudden multistep redox reaction occurred in the presence of the other potential sulfur donor, N‐acetyl‐L ‐cysteine (confirmed if glutathione was used instead). On the other hand, 1‐methylimidazole underwent an unprecedented acid–base reaction with the gold(III) complex, rather than the expected coordination to the metal center by replacing, for instance, a bromide. Our results are discussed herein and compared with the data available in the literature on related complexes; our findings confirm that the peculiar reactivity of gold(III)–dithiocarbamato complexes can lead to novel reaction pathways and, therefore, to new cytotoxic mechanisms in cancer cells.