Diethyldithiocarbamate Anion Research Articles

Sixth Ligand Induced HNO/NO- Release by a Five-Coordinated Cobalt(II) Nitrosyl Complex Having a {CoNO}8 Configuration.

Nitroxyl (HNO) and nitroxide (NO-) anion, the one-electron-reduced form of nitric oxide (NO), have been shown to have distinct advantages over NO from pharmacological and therapeutic points of view. However, the role of nitroxyl in chemical biology has not yet been studied as extensively as that of NO. Consequently, only a few examples of HNO donors such as Angeli's salt, Piloty's acid, or acyl- and acyloxynitroso derivatives are known. However, the intrinsic limitations of all of these hinder their widespread utility. Metal nitrosyl complexes, although few examples, could serve as an efficient HNO donor. Here, a cobalt nitrosyl complex of the {CoNO}8 (1) configuration has been reported. This complex in the presence of a sixth ligand [BF4-, DTC- (diethyldithiocarbamate anion), or imidazole] releases/donates HNO/NO-. This has been confirmed using well-known HNO/NO- acceptors like [Fe(TPP)Cl] and [Fe(DTC)3]. The HNO release has been authenticated further by the detection and estimation of N2O using gas chromatography-mass spectroscopy as well as its reaction with PPh3.

Chelation of Zn Cations as a Method for Their Replacement by Mn, Fe, Co in ZnSe Nanocrystals

This article describes a new technique for postsynthetic doping/alloying of Mn into ZnSe nanocrystals. The key feature is that it employs diethyldithiocarbamate anion to selectively bind the host cations and promote ion exchange. The presence of Mn in the product is confirmed with photoluminescence (PL) and total reflection X‐ray fluorescence spectroscopy. The cation exchange reaction takes place at temperatures as low as 100 °C. Higher temperatures allow to incorporate the impurity in greater quantities; however, after a crossover temperature of ≈200 °C, the process gets convoluted with Ostwald ripening and sulfide deposition, as evident from electron diffraction data, high‐resolution transmission electron microscopy (HR‐TEM), and elemental analysis of the samples. Studies of PL lifetime and quantum yield confirm these findings. Preliminary success is also shown for other impurities: Fe and Co are present in the respective samples in ≈17 at% of total metal content.

Can a Nitrosyl of a Mn(II)-Porphyrin Complex Release Nitroxyl/HNO?

In general, the nitrosyl complexes of Mn(II)-porphyrinate having the {Mn(NO)}6 configuration are not considered as HNO or nitroxyl (NO-) donors because of [MnI-NO+] nature. A nitrosyl complex of Mn(II)-porphyrin, [Mn(TMPP2-)(NO)], 1 [TMPPH2 = 5,10,15,20-tetrakis-4-methoxyphenylporphyrin], is shown to release HNO in the presence of HBF4. It is evidenced from the characteristic reaction of HNO with triphenylphosphine and isolation of the [(TMPP2-)MnIII(H2O)2](BF4), 2. This is attributed to the fact that H+ from HBF4 polarizes the NO group whereas the BF4- interacts with metal ion to stabilize the Mn(III) form. These two effects cooperatively result in the release of HNO from complex 1. In addition, complex 1 behaves as a nitroxyl (NO-) donor in the presence of [Fe(dtc)3] (dtc = diethyldithiocarbamate anion) and [Fe(TPP)(Cl)] (TPP = 5,10,15,20-tetraphenylporphyrinate) to result in [Fe(dtc)2(NO)] and [Fe(TPP)(NO)], respectively.

Bifunctional sulfur-ligated erbium complex: Crystal structure, magnetic and luminescent properties

Two isostructural mononuclear rare-earth complexes, [(dbm)2Er(dtc)(phen)] (1-Er) and [(dbm)2Tb(dtc)(phen)] (2-Tb) (dbm− = dibenzoylmethanoate anion, dtc− = diethyldithiocarbamate anion, phen = 1, 10-phenanthroline) were synthesized and structurally characterized by single-crystal X-ray diffraction analyses. Each complex consists of one sulfur-donor ligand, two oxygen-donor ligands and one auxiliary ligand, and Er3+/Tb3+ ion locates in a distorted square antiprism. Magnetic measurements show that 1-Er displays slow magnetic relaxation behavior under an applied field, and solid-state emission spectra reveal that 1-Er exhibits characteristic emissions of Er3+ ion in the visible and near-infrared regions, indicating the dual functionality of 1-Er. Neither slow relaxation of the magnetization nor characteristic emissions of Tb3+ ion were observed for 2-Tb.

Fine-tuning of the molecular structures and magnetic anisotropy analysis of two mononuclear dysprosium–sulfur complexes

Two mononuclear sulfur-based dysprosium complexes [(dtc)3Dy(bipy)] (1Dy, dtc− = diethyldithiocarbamate anion, bipy = 2,2′-bipyridine) and [(dtc)3Dy(dmbipy)]·0.68CH3CN (2Dy, dmbipy = 4,4′-dimethyl-2,2′-bipyridine) were successfully synthesized and structurally characterized by X-ray diffraction. The DyIII centers of 1Dy and 2Dy are eight-coordinated by six S atoms from three dtc− ligands and two N atoms from bipy (1Dy) or dmbipy (2Dy). Magnetic measurements reveal that the magnetic properties of 2Dy are obviously better than those of 1Dy. Theoretical calculations based on the molecular crystal structures are performed to analyze the difference of the magnetic behavior in two complexes.

Kinetics and mechanism of the ligand substitution reaction of [(H2O)(tap)2RuORu(tap)2(H2O)]2+ {tap = 2-(m-tolylazo)pyridine} with diethyldithiocarbamate anion in aqueous solution at pH 7.4

Kinetics and mechanism of the ligand substitution reaction of [(H2O)(tap)2RuORu(tap)2(H2O)]2+ {tap = 2-(m-tolylazo)pyridine} with diethyldithiocarbamate anion in aqueous solution at pH 7.4

Kinetic and Mechanistic Study of the Interaction of Diethyldithiocarbamate Anion with Diaquaethylenediamineplatinum(Ii) Ion in Aqueous Medium

The interaction of diethyldithiocarbamate (Et2DTC) with diaquaethylenediamineplatinum(II) has been studied spectrophotometrically in aqueous medium as a function of [substrate complex], [ligand], temperature and pH at constant ionic strength. The reaction proceeds via rapid outer-sphere association complex formation followed by two consecutive steps: the first is ligand dependent and second is assigned to intramolecular ring closure. The low enthalpy and negative entropy of activation indicate an associative mode of activation for both steps.

Kinetics and mechanism of the ligand substitution reaction of di-μ-hydroxobis(bipyridyl)dipalladium(II) ion with diethyldithiocarbamate anion in aqueous solution

The kinetics of the interaction between diethyldithiocarbamate (Et2DTC) and the title complex has been studied spectrophotometrically in aqueous medium as a function of nucleophile concentration, temperature and pH at constant ionic strength. The reaction is a two-step process in which the first step is ligand-dependent, but the second step is ligand-independent and is assigned to ring closure. The rate and activation parameters, conductivity studies and IR data were used to deduce a plausible mechanism. The kinetics of the interaction of diethyldithiocarbamate with di-μ-hydroxobis-(bipyridyl)dipalladium(II) ion in physiological pH at a constant ionic strength was studied spectrophotometrically. The reaction in aqueous medium exhibits a 2:1 metal ligand ratio. A two-step consecutive mechanism \(\left( {\text{A}\xrightarrow{{\text{k}_\text{1} }}\text{B}\xrightarrow{{\text{k}_\text{2} }}\text{C}} \right)\) involving formation of the ring-opened intermediate followed by ring closure is proposed.

Intermolecular Electron Transfer from Photogenerated Ru(bpy)3+ to [2Fe2S] Model Complexes of the Iron-Only Hydrogenase Active Site

Visible light-driven intermolecular electron transfer was observed from a reduced species Ru(bpy)3+, photogenerated via a reductive quenching of the ruthenium photosensitizer by a diethyldithiocarbamate anion, to bioinspired [2Fe2S] model complexes of the iron-only hydrogenase active site. The results indicate that Ru(bpy)32+ can act as a photoactive functional model of the [4Fe4S] cluster, playing the role of an electron-transfer relay. The photogenerated FeIFe0 species, which is proposed to be a crucial intermediate for proton reduction catalyzed electrochemically by the [2Fe2S] complexes, gives promise in the light-driven dihydrogen evolution using diiron complexes as surrogates of noble platinum catalysts.

NICKEL(II) COMPLEXES CONTAINING MIXED ALKYLSALICYLALDIMINATE AND ALKYLXANTHATE OR DIETHYLDITHIOCARBAMATE LIGANDS

Stable mixed-ligand complexes of Ni(II) alkylsalicylaldiminate Schiff base and alkylxanthate or diethyldithiocarbamate have been prepared. The complexes have the general formulae K[Ni(Rsal)(R'xan)2] and [Ni(Rsal)(Et2NCS2)] where Rsal = ethyl, isopropyl or isobutyl salicylaldiminate; Rxan′ = methyl-, ethyl- or butylxanthate and Et2NCS2 − = diethyldithiocarbamate anion. The complexes have been characterized and studied by elemental analyses, conductivity, IR and electronic spectra as well as by thermogravimetry. All data indicate that the xanthate complexes have an octahedral structure and the xanthate group is attached in a bidentate fashion to the nickel(II) ion. For the dithiocarbamate complexes, a square-planar structure is confirmed and the dithiocarbamate anion coordinates as a bidentate ligand.

ChemInform Abstract: A One‐Pot Rapid Synthesis of Dithiocarbamates from Alcohols Using a Polymer Supported Diethyl Dithiocarbamate Anion.

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A one-pot rapid synthesis of dithiocarbamates from alcohols using a polymer supported diethyl dithiocarbamate anion

A polymer supported diethyl dithiocarbamate anion reacts with primary and secondary alcohols via their tirfluoracetates giving alkylated diethyl dithiocarbamates in good yields.

Syntheses, Structures, and Magnetic Properties of Di-μ3-Chloride-Bridged Tripalladium Compounds, [Pd3(μ3-Cl)2(HqnS)6]Cl2 (HqnS = Quinoline–2(1H)–thione) and [Pd3(μ3-Cl)2(Et2dtc)2(PPh3)2]·C6H6(Et2dtc = N, N′–Diethyldithiocarbamate)

Abstract Two triangular tripalladium compounds, [Pd3(μ3-Cl)2(HqnS)6]Cl2 (1) (HqnS = quinoline–2(1H)–thione), and [Pd3(μ3-Cl)2(Et2dtc)2(PPh3)2]·C6H6 (2) (Et2dtc = N, N′-diethyldithiocarbamate anion), were prepared. Their single crystal X-ray structure analyses revealed they have a similar trigonal bipyramidal framework of Pd3(μ3-Cl)2 with two chlorine atoms in apical positions. Each Pd atom in all clusters has two additional coordination sites to establish a square planar cis-PdL2(μ3-Cl)2 geometry. In compound 1, six sulfur atoms of six HqnS ligands with thion form are coordinated to the vacant sites of the Pd3(μ3-Cl)2 core. Two coordination sites of one of the three Pd atoms in 2 are occupied by two triphenylphosphines and those of the other two are coordinated by two S atoms of Et2dtc. Although both compounds have 50 valence electrons, only 1 shows paramagnetic behavior. Crystallographic data are as follows. 1: Pd3Cl4S6N6C54H42, triclinic, P1- a = 14.988(5), b = 17.328(3), c = 12.642(1) Å, α = 93.61(1), β = 96.06(2), γ = 71.79(2)°, V = 3099(1) Å3, and Z = 2. 2: Pd3Cl2P2S4N2C52H56, monoclinic, P21, a = 12.278(5), b = 17.426(6), c = 12.630(3) Å, β = 94.65(3)°, V = 2693(2) Å3, and Z = 2.

Comparison of the partition between polar and SET pathways in the S RN1 mechanism for the nitronate and diethyldithiocarbamate anions. An unexpected result

Competition between S RN1 and S N2 mechanisms is discussed according to the stereochemical results in the alkylation of two anions by optically active α-chloro paranitrophenylethane 1. In the reaction of 1 with the ambident anion of 2-nitropropane 2, competing S RN1 and S N2 processes take place, giving C-alkylation 3 with complete racemization and O-alkylation 4 products respectively. On the other hand, S-alkylation of the diethyldithiocarbamate anion 5 by the halide 1 involves also an S RN1-S N2 competition giving the same product 6 with an indication of a less important participation of the S RN1 pathway despite the fact that dithiocarbamate is a better reducing agent than nitronate.

Simple and Mixed Ligand Complexes of Ag(I) Involving Substituted Dithiocarbamic Acids, Triphenylphosphine and the Chelating Phosphine Diphos-A Synthetic and Spectrophotometric Study

Abstract Silver(I), being a soft acid shows a preference for P and S containing ligands. In the present study, simple and mixed ligand complexes of Ag(I) involving mono-and diethanoldithiocarbamates, Ag(MEADTC) and Ag(DEADTC), with triphenylphosphine and 1,2-bis(diphenylphosphino)ethane (diphos) were synthesized. For a comparison, Ag(DEDTC), the diethyl analogue, was also synthesized and the properties studied with IR, UV-visible, TG, DT techniques. The mixed ligand complexes involving PPh3 and diphos viz., Ag(DEDTC)(PPh3)2, Ag(DEDTC)(diphos), Ag(DEADTC)(PPh3)2 and Ag(DEADTC)(diphos) (DEDTC− = diethyldithiocarbamate anion, DEADTC− = diethanoldithiocarbamate anion) showed very low conductivity indicating non-ionic character and ruled out possible ion pair formation such as [(PPh3)2Ag]+DEDTC− or [(diphos)Ag]+DEDTC− proposed earlier. In addition, the isolated Ag(MEADTC) complex was found to be highly unstable and, hence, an equilibrium study was made and the stability constant was determined to be 6.1 ± 0.2 ...

Black MLCT Absorbers

[Extract] A general approach has been developed for the preparation of heteroleptic tris(bidentate)ruthenium(II) complexes which exhibit significant continuous light absorption throughout the UV and visible regions. It utilizes separate metal-to-ligand charge transfer (MLCT) transitions to different heterocyclic ligands and the incorporation of the diethyldithiocarbamate anion (Et₂dtc-) to shift the MLCT bands uniformly to the red. In the spectrum of [Ru{(EtCO₂)₂bpy}(dpa)(Et₂dtc)]⁺ ((EtCO₂)₂bpy is 4,4'-bis(carboxyethyl)-2,2'-bipyridine) significant absorption (e > 3000) extends past 700 nm. These complexes can be photochemically inert and exhibit near-IR emission with appreciable excited state lifetimes.

Nature of the transient species in the one-electron oxidation of diethyl dithiocarbamate as studied by pulse radiolysis

One-electron oxidation of the diethyl dithiocarbamate (DDC) anion by oxidising radicals such as ˙OH, N3˙, Br2˙–etc. has been studied employing the pulse radiolysis technique. The transient species absorbing in the visible region (λmax 570 nm) has been identified as the dimer anion radical formed by the interaction of the initial neutral radical (Et2NCS2˙) with the parent anion. This species was found to be rather unreactive towards other solutes and decayed, with second-order kinetics, to give disulfiram. The reaction of disulfiram with hydrated electrons (e–aq) gave rise to the same transient spectrum as obtained in the case of one-electron oxidation of DDC. The reaction of e–aq with DDC at pH 9 gave a transient spectrum with λmax 340 nm which has been attributed to a carbon-centred radical dianion (Et2NCS2˙2–).

Synthesis, spectroscopic, and cytotoxicity studies of some diamine and diimine platinum(II) complexes of diethyldithiocarbamate

Four new water soluble complexes of the formula [Pt(DA)(DDTC)]NO 3 (where DA is 2,2'-bipyridine, 1,10-phenanthroline, 1,2-diaminopropane, or 1,2-diaminocyclohexane, and DDTC is diethyldithiocarbamate anion) have been synthesized by reaction of platinum-diamine/diimine diaqua complex with sodium diethyldithiocarbamate in molar ratio of 1:1. These complexes have been characterized by the chemical analysis, and ultraviolet-visible, infra-red and 1H NMR spectroscopy. The infrared and 1H NMR spectral studies of these complexes have ascertained the modes of binding of diamine/diimine and diethyldithiocarbamate to platinum. The molar conductance values of these platinum complexes in conductivity water suggest them to be 1:1 electrolytes. These four complexes and two other complexes containing ethylenediamine and 1,3-diaminopropane ligands have been tested against P-388 lymphocytic leukemic cells. Out of them only 2,2'-bipyridine and 1,10-phenanthroline complexes show I.D. 50 values less than cisplatin.

In vitro cytostatic activity of palladium(II) and platinum(II) halide complexes with thiocarbamic esters

The thiuram disulfides and dithiocarbamates are widely used in industry, agriculture and medicine [1, 2]. Moreover disulfiram (tetraethylthiuram disulfide) has been used for over 20 years in the treatment of certain patients with chronic alcoholism and the reduced form of the compound, diethyldithiocarbamate anion (DDTC) has been used in the treatment of nickel carbonyl, arsenic and thallium poisoning [3]. Recently DDTC has been found to be an effective agent in attempts to reduce the dose-limiting nephrotoxicity of cis-platin [4]. This compound has been shown also to exert a protective effect against a variety of chemically-induced malignant tumors and a unique immunopotentiating activity [5]. Bearing in mind these findings, in recent years we have undertaken to study platinum(II) and palladium(II) complexes with thiocarbamate derivatives as ligands, in order to prepare new antitumor platinum metal complexes with a better therapeutic index than cis-platin [6,7]. The present note reports a new series of platinum(II) and palladium(II) complexes containing as ligands dithiocarbamic esters of the type L =R 1R 2N · CSSR (R 1 = R 2 = R = Me, L = TMDT; R 1 = R 2 = Me, R = Et, L = DMDTE; R 1 = R 2 = R = Et, L = TEDT; R 1 = R 2 = Et, R = Me, L = DEDTM). Whereas by reacting PtX 2 and PdX 2 (X = Cl, Br) with TMDT and DMDTE, complexes of 1:1 molar ratio, MLX 2, and 1:2, ML 2X 2 have been isolated, with DEDTM and TEDT only 1:1 adducts have been obtained. On the basis of the IR data the ligands act as monodentate through the thiocarbonyl group in the 1:2 complexes; for the 1:1 a tetracoordination by one bidentate (S,S) dithiocarbamic ester molecule and two halides is suggested. The cytostatic activity was evaluated on KB cells according to protocols suggested by the National Cancer Institute (Bethesda) [8]. Results of an in vitro assay are expressed as concentration of the compound in culture medium (μg/ml) required to inhibit growth by 50% (ID 50). Some of the compounds showed significant cytostatic activity in the preliminary test. Particularly Pd(DMDTE)X 2 (X = Cl, Br), Pt(DMDTE)Br 2 and Pd(DMDTE) 2Br 2 have ID 50 values in the 0.5 - 1 μg/ml interval. The ligands alone did not show any activity From the preliminary results the palladium complexes seem to posses a higher cytostatic activity than platinum analogues.

In vitro cytostatic activity of palladium(II) and platinum(II) halide complexes with thiocarbamic esters

Abstract The thiuram disulfides and dithiocarbamates are widely used in industry, agriculture and medicine [1, 2]. Moreover disulfiram (tetraethylthiuram disulfide) has been used for over 20 years in the treatment of certain patients with chronic alcoholism and the reduced form of the compound, diethyldithiocarbamate anion (DDTC) has been used in the treatment of nickel carbonyl, arsenic and thallium poisoning [3]. Recently DDTC has been found to be an effective agent in attempts to reduce the dose-limiting nephrotoxicity of cis -platin [4]. This compound has been shown also to exert a protective effect against a variety of chemically-induced malignant tumors and a unique immunopotentiating activity [5]. Bearing in mind these findings, in recent years we have undertaken to study platinum(II) and palladium(II) complexes with thiocarbamate derivatives as ligands, in order to prepare new antitumor platinum metal complexes with a better therapeutic index than cis -platin [6,7]. The present note reports a new series of platinum(II) and palladium(II) complexes containing as ligands dithiocarbamic esters of the type L =R 1 R 2 N · CSSR (R 1 = R 2 = R = Me, L = TMDT; R 1 = R 2 = Me, R = Et, L = DMDTE; R 1 = R 2 = R = Et, L = TEDT; R 1 = R 2 = Et, R = Me, L = DEDTM). Whereas by reacting PtX 2 and PdX 2 (X = Cl, Br) with TMDT and DMDTE, complexes of 1:1 molar ratio, MLX 2 , and 1:2, ML 2 X 2 have been isolated, with DEDTM and TEDT only 1:1 adducts have been obtained. On the basis of the IR data the ligands act as monodentate through the thiocarbonyl group in the 1:2 complexes; for the 1:1 a tetracoordination by one bidentate (S,S) dithiocarbamic ester molecule and two halides is suggested. The cytostatic activity was evaluated on KB cells according to protocols suggested by the National Cancer Institute (Bethesda) [8]. Results of an in vitro assay are expressed as concentration of the compound in culture medium (μg/ml) required to inhibit growth by 50% (ID 50 ). Some of the compounds showed significant cytostatic activity in the preliminary test. Particularly Pd(DMDTE)X 2 (X = Cl, Br), Pt(DMDTE)Br 2 and Pd(DMDTE) 2 Br 2 have ID 50 values in the 0.5 - 1 μg/ml interval. The ligands alone did not show any activity From the preliminary results the palladium complexes seem to posses a higher cytostatic activity than platinum analogues.