Sodium Disulfide Research Articles

Rhenium(V) Tris(pyrazolyl)borate Thiolate Complex with the Disulfide Bridging Ligand: Synthesis and Structure

The reaction of TpReOCl(StBu) (Tp = tris(pyrazolyl)borate anion) with sodium disulfide in dimethoxyethane affords the new binuclear rhenium complex [TpReO(μ-StBu)]2(μ-S2) (I). Complex I can also be synthesized by the reaction of TpReO(StBu)2 with a suspension of manganese(II) bromide in toluene accompanied by the dealkylation of one of the ligands to form one more new complex [TpReO]2(μ-S2)(μ-S) (II) containing the bridging sulfide and disulfide ligands. The structures of two crystalline solvates of complex I with dichloromethane containing the molecules with different conformations of the Re2S2 fragment (Ia and Ib) and complex II are studied by X-ray diffraction (XRD) (CIF files ССDC nos. 2262677, 2262678, and 2267423 for Ia, Ib, and II, respectively).

Facile synthesis and polymerization of 1,4,5-oxadithiepan-2-one for disulfide-based redox-responsive drug delivery

Chemotherapeutic drugs have been shown to be promising for the treatment of tumors, however, they are associated with several disadvantages including low aqueous solubility, non-specificity, and poor plasma stability. Hence, they accumulate in the health organs and create several adverse effects. Drug encapsulated stimuli-responsive nanoparticles bearing redox-responsive disulfide linkages have emerged as promising delivery vehicle to address these limitations. A glutathione (GSH) responsive disulfide-based drug delivery system based on a polyethylene glycol methyl ether (PEGME) and a polydisulfide (PDS) diblock copolymer has been developed. The cyclic lactone containing a disulfide link, 1,4,5-oxadithiepan-2-one, was prepared using a thiol-free method utilizing the reaction of 2-bromoethyl bromoacetate with sodium disulfide. Ring-opening polymerization (ROP) of 1,4,5-oxadithiepan-2-one using 1-butanol in the presence of Sn(oct)2 generated the homopolymer PDS whereas the diblock copolymer PEGME-b-PDS was obtained when PEGME was used as a macroinitiator. In aqueous solution, PEGME-b-PDS self-assembled into spherical-shaped micelles with a hydrodynamic radius of 146 and 116 nm as measured by Field-emission Scanning Electron Microscopy (FESEM) and Dynamic Light Scattering (DLS), respectively. At pH = 7.4, a Doxorubicin (DOX) loaded PEGME-b-PDS micelle showed a cumulative release of ∼98.2, ∼9.9, and ∼1.9 % in presence of 2 mM, 2 μM DTT and in absence of DTT, respectively clearly demonstrating the redox responsiveness of the PDS block. The best fit of kinetic data using with the Korsmeyer-Peppas model suggests a Fickian diffusion as well as chain-relaxation controlled drug release process. DOX loaded micelles and free DOX displayed similar cytotoxicity towards both 4T1 and MCF-7 cells indicating that the encapsulation inside the micelle did not affect the anticancer efficacy of the drug. The drug loaded micelle showed higher cellular uptake than free DOX in both 4T1 and MCF-7 lines and lower cellular uptake than free DOX in 3T3-L1 cell lines. This polymeric micellar nanoparticle may be further exploited for encapsulation of other hydrophobic drugs.

Ultrasensitive and selective electrochemical sensor for nanomolar dopamine determination based on MnS/Co3S4 hybrids embedded on electrochemically reduced graphene oxide

An ultrasensitive and selective electrochemical sensor has been constructed for the quantitative assay of dopamine (DA) based on hollow tubular manganese-cobalt sulfide (MnS/Co3S4) hybrids embedded on electrochemically reduced graphene oxide (ErGO). The MnS/Co3S4 heterostructures were created by two-step ion exchange method, of which Co9S8 with hollow tubular structures was fabricated by solvothermal method using the self-made cobalt chloride carbonate hydroxide (CO(CO3)0.35Cl0.20(OH)1.10) as precursor and sodium disulfide monohydrate as sulfur source and manganese chloride as manganese source. The MnS/Co3S4-ErGO/GCE could exhibit strong catalytic ability for the redox reaction of DA. Under the optimal conditions, the developed sensor exhibits a wide linear response for DA ranging from 6.0 nM to 20.0 μM by second-order derivative linear sweep voltammetry (SDLSV), with a detection limit of 2.0 nM. In addition, the developed method exhibited high sensitivity and selectivity, good reproducibility and low-cost. It is a very promising analytical method for the determination of DA in pharmaceutical and biological samples.

UNSYMMETRICAL DISULPHIDES AS ADDITIVES TO TRANSMISSION OILS

This paper presents the results of studies of the anti-seize properties of (2,2-dimethyl-4-methylene1,3-dioxolane-allyl and benzyl)disulfides synthesized on the basis of 2,2-dimethyl-4-chloromethyl-1,3- dioxolane, sodium disulfide and allyl and benzyl chlorides, respectively, in the composition of transmission oils. The synthesized compounds are new compounds not previously described in the literature, the structure of which has been proven by studying their physicochemical properties, elemental composition, and IR spectroscopy. It revealed that the synthesized compounds in terms of extreme pressure efficiency are significantly superior to transmission oil MS-20, as well as bis(2,2-dimethyl-4-methyl-1,3- dioxolane)disulfide, previously synthesized by the authors of this article and a typical extreme pressure additive ethylene-bis-isopropylxanthate (LZ-23k). It found that the replacement of one of the 1,3-diocosolane fragment in bis(2,2-dimethyl-4-methylene-1,3-dioxolane) disulfide with allyl or benzyl radicals leads to an improvement in anti-seize properties due to their better adsorption on metal surfaces of rubbing parts.

Perbandingan Fisik dan Organoleptik Antara Marshmallow dengan Bahan Dasar Gelatin yang Berbeda

This study aims to determine the comparison of physical and orgnoleptic qualities between marshmallows made from chicken claws and cow skin with the parameters being tested for taste, chewiness, texture and preference. This research was conducted in July-August 2020 at the laboratory of the Boyolali Veterinary Public Health Service Center and tested on panelists at the Daarul Arqom Tulung Modern Islamic Boarding School, Klaten. The material used consists of two, namely raw materials and manufacturing tools. First, the materials used to make gelatin in this study include chicken claws, cow skin, acetic acid, water, sodium disulfide S), calcium hydroxide ( ) and HCl. Meanwhile, the ingredients used include chicken claw gelatin, cow skin gelatin, vanilla, sucrose syrup, sugar, cornstarch, sugar flour and water. The tools used include basins, measuring cups, scales, scissors, waterbath (water bath), filter paper, vacuum filters, oven and blender. The results of the analysis of various organoleptic tests in this study which included texture, chewiness, taste and liking had a significant difference of P <0.01, namely that marshmallows with cowhide were better than marshmallows with chicken claw as the basic ingredient. The conclusion of the comparative study between marshmallow with gelatin as a base ingredient of cow skin gelatin is superior to that of chicken claw gelatin.
 Keywords:marshmallow, cowhide, chicken claw

In vitro anticancer activity of hydrogen sulfide and nitric oxide alongside nickel nanoparticle and novel mutations in their genes in CRC patients

This study was carried out to assess the impact of nickel nanoparticles (NiNPs) as well as scorpion venom on colorectal cancer (CRC) cells in the presence and/or absence of 5-fluorouracil (5-FU), hydrogen sulfide (H2S), and nitric oxide (NO) donors and to determine alterations in endothelial NO synthase (eNOS) and cystathionine γ-lyase (CSE) enzyme-producing genes in CRC patients. The IC50 of both H2S and NO donors, along with NiNPs, were determined. The CRC cells were treated for 24hrs, and the cytotoxic activities were assessed using the MTT test. Moreover, the apoptosis was determined after 24hrs and 48hrs using TUNEL assay. Furthermore, the mutations in the eNOS gene (intron 4, -786T>C and 894 G>T) and CSE gene (1364GT) were determined using direct sequencing. The IC50 values for sodium disulfide (Na2S) and sodium nitroprusside (SNP) at 24hrs treatment were found to be 5 mM and 10−6 M, respectively, while the IC50 value for 5-FU was reached after 5-days of treatment in CRC cell line. Both black and yellow scorpion venoms showed no inhibition of cell proliferation after 24hrs treatment. Furthermore, Na2S showed a significant decrease in cell proliferation and an increase in apoptosis. Moreover, a co-treatment of SNP and 5-FU resulted in inhibition of the cytotoxic effect of 5-FU, while a combination treatment of NiNPs with Na2S, SNP, and 5-FU caused highly significant cytotoxicity. Direct sequencing reveals new mutations, mainly intronic variation in eNOS gene that has not previously been described in the database. These findings indicate that H2S promotes the anticancer efficiency of 5-FU in the presence of NiNPs while NO has antiapoptotic activity in CRC cell lines.

Poly(butylene disulfide) and poly(butylene tetrasulfide): Synthesis, cure and investigation of polymerization yield and effect of sulfur content on mechanical and thermophysical properties

In this work, two polysulfide polymers were synthesized by use of 1,4-dichlorobutane and aqueous sodium disulfide or sodium tetrasulfide. The polymers were cured at 85 °C. The structural characteristics of non-cured and cured samples were identified by Raman and FT-IR spectroscopy. The morphological and the thermophysical properties of all samples were investigated by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Also, the mechanical properties and hardness of all samples were investigated by tensile test and Shore A. Moreover, the effects of temperature and ethanol on polymerization were investigated. Aqueous monomers were characterized by UV-VIS-NIR spectroscopy. The molecular weight of the synthesized samples was determined by 1H NMR spectroscopy. The results showed that, before curing, poly(butylene tetrasulfide) (PBTS) due to amorphous structure does not have a melting peak and both polymers have a very low glass transition temperature. Without ethanol, no polymerization reaction takes place. Before curing, poly(butylene disulfide) (PBDS) is brittle and PBTS has an elastomeric behavior, but after curing PBDS also behaves as elastomer. The curing times of the two polymers are close to each other, but their mechanical properties and hardness are different.

The vasodilatory mechanism of nitric oxide and hydrogen sulfide in the human mesenteric artery in patients with colorectal cancer.

Recent studies have focused on the role of gasotransmitters in cancer progression and prevention. Therefore, the current study was designed to explore the vasodilator activity of NO and H2S in the human mesenteric arteries of patients with colorectal cancer (CRC) via the activation of K+ channels. A total of two sets of experiments were established for the current investigation. Blood samples from patients with CRC were obtained to detect serum levels of endocan and malondialdehyde (MDA). The role of K+ channels in mediating the vasodilation of the human mesenteric artery in response to sodium nitroprusside (SNP) and sodium disulfide (Na2S) was assessed. The level of serum endocan was indicated to be decreased in patients with CRC compared with healthy individuals, while the level of serum MDA remained unaltered between groups. The arterial rings pre-contracted with norepinephrine were first relaxed by the cumulative addition of increasing concentrations of either SNP (30 nM-30 µM) or (1-6 mM). Maximal relaxation rates were then calculated at 15 min intervals for 60 min. Pre-incubation of arterial rings for 20 min with individual K+ channel blockers was indicated to significantly reduce SNP- and Na2S-induced relaxation at different time points. Pre-treatment of L-nitro-arginine methyl ester did not alter vasodilation that was induced by Na2S. Furthermore, vasodilation of the CRC mesenteric artery was not altered by the synergistic application of SNP and Na2S, while pre-incubation of arterial rings with D,L-propargylglycine significantly enhanced vasodilation induced by SNP. These results indicated that endothelial dysfunction and oxidative stress do not serve roles in the pathogenesis of CRC. The dilatory mechanisms of NO and H2S in mesenteric arteries of patients with CRC were K+ channel- and time-dependent, and the activity of cystathionine γ-lyase enzyme inhibited the ability of exogenous NO in vasodilation processes.

Effect of the bleaching and varnishing process on the flame source combustion light intensity of wood material

Bu calisma, ahsap malzemede renk acma ve vernikleme isleminin alev kaynakli yanmada isik yogunluguna etkilerini belirlemek amaciyla yapilmistir. Bu maksatla, Dogu kayini (Fagus orientalis Lipsky), saricam (Pinus sylvestris Lipsky) ve Sapsiz mese (Querqus petraea Liebl.) odunlarindan ASTM D 358 esaslarina uyularak hazirlanan orneklere sodyum hidroksit (NaOH), hidrojen peroksit (H2O2), kalsiyum hidroksit (Ca(OH)2), sodyum silikat (NaSiO3), asetik asit (CH3COOH), sodyum disulfit (Na2S2O5), oksalik asit (C2H2O4) ve potasyum permanganat (KMnO4)’in % 18’lik cozeltisi ile renk acma islemi yapildiktan sonra, ASTM D3023 esaslarina gore su bazli (Sb), sentetik (Sn), poliuretan (Pu) ve akrilik (Av) vernikler uygulanmis ve isik yogunlugu ASTM E 160–50 esaslarina gore belirlenmistir. Sonuc olarak, isik yogunlugu; ahsap turu, renk acma cozeltisi ve vernik cesidi etkilesimine gore en fazla KMnO4+Na2S2O5+H2O2 (R5) ile rengi acilmis sentetik vernikli kayinda gorulurken, en az Na2S2O5+C2H2O4 (R4) ile rengi acilmis akrilik vernikli saricamda elde edilmistir. Buna gore isik yogunlugu en az olan ornekler, yanginda dumandan bogulma riskini arttirabileceklerinden uygulama alanlarinda bu durumun dikkate alinmasi onerilebilir.

Poly(p-xylene disulfide) and poly(p-xylene tetrasulfide): synthesis, cure and investigation of mechanical and thermophysical properties

In this work, two polysulfide polymers were synthesized using aromatic organic monomer (α,α′-dichloro-p-xylene) and sodium disulfide (Na2S2) and sodium tetrasulfide (Na2S4) aqueous monomers. Then, the curing process of the polymers was carried out at 170° C using a rheometer. The structural characteristics of synthesized and cured samples were identified by Raman and Fourier transform infrared (FT-IR) spectroscopies. Also, morphological and thermophysical properties of samples were studied by using the X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. Moreover, the molecular weight of the synthesized samples was determined by proton nuclear magnetic resonance (1H NMR). Furthermore, the mechanical properties and hardness of the samples were investigated by tensile test and Shore A. The results showed that in the noncured samples during the increase of sulfur in the polymer structure, solubility was increased whereas it decreased the hardness, melting point (Tm ) and glass transition temperature (Tg ) of polymers. But in cured samples, hardness and Tg increase by increasing sulfur and the mechanical properties also improved. This is due to the increase in crosslinks. Also, Tm and solubility are not observed due to the formation of crosslinks.

Selective and Facile Synthesis of Sodium Sulfide and Sodium Disulfide Polymorphs.

Na2S and Na2S2 were selectively synthesized using a microwave-assisted thermal treatment of a Na+/S solution in tetraglyme between 100 and 200 °C, considerably lower than that of current routes. This novel synthetic pathway yields the Na2S phase in high purity and allows for good selectivity between the polymorphs of Na2S2 (α and β phases). These materials show promising electrochemical properties and are particularly interesting for the continued development of Na-S batteries.

Aqueous MCRs of quaternary ammoniums, N-substituted formamides and sodium disulfide towards aryl thioamides

A three-component reaction of quaternary ammonium salts, N-substituted formamides and aqueous sodium disulfide was developed, leading to aryl/heteroaryl thioamides in moderate to good yields with good functional group compatibility.

Facile Synthesis of Monodispersed Polysulfide Spheres for Building Structural Colors with High Color Visibility and Broad Viewing Angle.

The synthesis and assembly of monodispersed colloidal spheres are currently the subject of extensive investigation to fabricate artificial structural color materials. However, artificial structural colors from general colloidal crystals still suffer from the low color visibility and strong viewing angle dependence which seriously hinder their practical application in paints, colorimetric sensors, and color displays. Herein, monodispersed polysulfide (PSF) spheres with intrinsic high refractive index (as high as 1.858) and light-absorbing characteristics are designed, synthesized through a facile polycondensation and crosslinking process between sodium disulfide and 1,2,3-trichloropropane. Owing to their high monodispersity, sufficient surface charge, and good dispersion stability, the PSF spheres can be assembled into large-scale and high-quality 3D photonic crystals. More importantly, high structural color visibility and broad viewing angle are easily achieved because the unique features of PSF can remarkably enhance the relative reflectivity and eliminate the disturbance of scattering and background light. The results of this study provide a simple and efficient strategy to create structural colors with high color visibility, which is very important for their practical application.

Synthesis and characterization of ethylene-xylene-based polysulfide block-copolymers using the interfacial polymerization method

ABSTRACTCopolymers of linear and aromatic polysulfide blocks are synthesized using interfacial polymerization of dichloro-xylene-based aromatic and ethylene-dichloride-based non-aromatic organic monomers. Synthesized copolymers consist of poly(ethylene sulfide) as well as ploy (xylene sulfide) blocks. Fascinating properties of linear and aromatic polysulfide species are gathered in the structure of synthesized polysulfide copolymers. Ethylene dichloride and α,α′-dichloro-p-xylene are used as the non-aromatic and aromatic organic monomers, respectively. To investigate the influences of sulfur contents in the backbone of the polymer on the thermal stability of synthesized copolymers, poly(ethylene-xylene disulfide) (PEXDS), poly(ethylene-xylene trisulfide) (PEXTRS) and poly(ethylene-xylene tetrasulfide) (PEXTS) copolymers are synthesized using, respectively, sodium disulfide, sodium trisulfide and sodium tetrasulfide, as aqueous monomers. Compared to both linear and nonlinear homopolymers, synthesized copolymers exhibit improved thermal stability. Moreover, the thermal degradation temperatures of synthesized copolymers improve by decreasing the number of sulfur atoms in the backbone of copolymers. These results reveal that thermal degradation of polysulfide copolymers can be tailored by controlling the polysulfide chain’s sulfur contents. Structural characteristics of synthesized polysulfide copolymers are also investigated using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and X-ray diffraction analysis.

Sulfuration treatment of electroplating wastewater for selective recovery of copper, zinc and nickel resource

In the electroplating process, various metal salts are used and the residues on the surface of electroplated materials are rinsed out as wastewater, followed by hydration in a wastewater disposal step. Although a variety of metals are concentrated in the sludge, the mixed heterogeneous state of these metals in sludge makes it difficult to recycle and reuse them. From the viewpoint of environmental protection as well as resource saving, effective methods for recycling and reuse of these mixed metal sludge are required to be developed urgently. In the present work, selective recovery of the metals from mixed-metal wastewater by sulfuration treatment is proposed. Sulfuration treatment is characterized by low solubility of metal sulfides; metal sulfides are, in general, lower in solubility than that of metal hydroxides. For the experiments, three metals of copper, zinc and nickel which are commonly used in the electroplating process were chosen. Separation of these metals from the mixed solution in various pH ranges was conducted by employing three sulfurating agents: sodium sulfide (Na2S), sodium disulfide (Na2S2) and sodium tetrasulfide (Na2S4). Aqueous solutions of CuSO4, ZnSO4 and NiSO4 and those of real plating wastewater, of which the initial concentrations were adjusted to 100-300 mg dm-3 were employed. By sulfuration treatment of the simulated solution using each sulfurating agent without adjusting pH, CuS was first precipitated, but ZnS and NiS were also precipitated at the same time. In addition, pH value increased with the amount of sulfurating agents in the solution. The results demonstrated that the formation behavior of metal precipitates depended on pH value of the solution. For the sulfuration with three kinds of sulfurating agents, copper was first separated from the solution as CuS in pH=1.4-1.5, then ZnS was precipitated in pH=2.4-2.5, followed by the precipitation of nickel sulfide, NiS in the residual solution at pH=5.5-6.0. It was also found that Na2S is most effective for selective precipitation of metal sulfides, among the three sulfurating agents of Na2S, Na2S2 and Na2S4. The selectivity of CuS in the filtrated cake obtained by the sulfuration treatment in pH=1.4-1.5 was about 94 % and was sufficiently high, in terms of allowable metal content level for recycling. The sequent selectivity of ZnS and NiS in the cake after the sulfuration treatment in pH=2.4-2.5 were 75-77 % and about 20 %, respectively. The selectivity of NiS and ZnS in the cake after the sulfuration treatment in pH=5.5-6.0 was 64-66 % and 33-35 %, respectively.

Characterization of synthesized poly(aryldisulfide) through interfacial polymerization using phase-transfer catalyst

A new polysulfide polymer was synthesized from 1,4-bis(chloromethyl)-benzene and sodium disulfide by an interfacial polycondensation technique in the presence of tetrabutyl ammonium bromide, methyltributyl ammonium chloride and benzyl triethyl ammonium chloride as phase-transfer catalysts (PTC). The effect of PTC on the kinetics of polymerization was investigated. Structures of this aromatic polysulfide were confirmed through elemental analyses, attenuated total reflectance Fourier transform infrared spectroscopy, Raman spectroscopy, an X-ray diffraction technique, and a nuclear magnetic resonance spectroscopy method. The thermal behavior of this polymer was also characterized by differential scanning calorimetry and thermogravimetric analysis. The solubility of prepared polymer was critically dependent on the identity of the solvent.

Presence of alternating glucosaminoglucan in the sheath of Thiothrix nivea

A sheath-forming sulfa oxidizer, Thiothrix nivea, was mixotrophically cultured in a medium supplemented with acetic acid and sodium disulfide. Its sheath, a microtube-like extracellular supermolecule, was prepared by selectively removing the cells with lysozyme, sodium dodecyl sulfate, and sodium hydroxide. The sheath was not visibly affected by hydrazine treatment, suggesting that it is not a proteinous supermolecule. From the acid hydrolysate of the sheath, glucose and glucosamine were detected in an approximate molar ratio of 1:1. Three other saccharic compounds were detected and recovered by HPLC as fluorescent derivatives prepared by reaction with 4-aminobenzoic acid ethyl ester. Nuclear magnetic resonance (NMR) analysis suggested that one of the derivatives was derived from an unidentified deoxypentose. NMR analysis for the other 2 derivatives showed that they were derived from β-1,4-linked disaccharides and tetrasaccharides, which were composed of glucose and glucosamine. The sheath was readily broken down by weak HCl treatment, releasing an unidentified deoxypentose and polymer. Chemical analysis showed the presence of β-1,4-linked d-Glcp and d-GlcNp in the polymer. NMR analysis revealed that the polymer had a repeating unit of →4)-d-Glcp-(β1→4)-d-GlcNp-(β1→. The solid-state 1D-13C NMR spectrum of the polymer in N-acetylated form supported this result. The molecular weight of the polymer was estimated to be 8.2×104 by size exclusion chromatography. Based on these results, the sheath of T. nivea is hypothesized to be assembled from alternately β-1,4-linked glucosaminoglucan grafted with unidentified deoxypentose.

Modified synthesis and quality control of tiopronin

Objective To improve synthesis technology and content detection method of tiopronin.Methods Tiopronin was synthesized from α-bromo-propanoic acid via acylation, reacting with aminoacetic acid, then with sodium disulfide to obtain α-mercaptopropionyl and aminoacetic acid dimmer.The chemical directly synthesized with zinc powder to produce tiopronin. Chemical titration method was used to determine the content of tiopronin. Results The overall yield was 29% and met with the standard.Gonclusions The modified method is more suitable for industry apply. Key words: Tiopronin; Modified synthesis; Quality control

Evaluation of a molybdenum sulfide reference electrode in hot alkaline solutions

This investigation evaluated the applicability of a molybdenum sulfide reference electrode (MSRE) as an internal reference electrode for use in alkaline sulfide solutions over a range of pulp digester liquors at 170°C. The electrode remained stable during the exposure period of two weeks. The experimentally determined half cell potential of the MSRE is E = -0.91 VSHE. The surface of the MSRE was examined by scanning electron microscope (SEM) and electron spectroscopy for chemical analysis (ESCA) to verify the chemical composition of the thin surface film. Based on ESCA studies, the surface film contained molybdenum disulfide and sodium disulfide. During storage of the specimens, sulfide was partly oxidized to sodium sulfite in air. Next to the metallic molybdenum, a mixed molybdenum disulfide and molybdenum hydroxide layer was detected.

Thieme Chemistry Journal Awardees - Where Are They Now? [3]-Cumulenes, Sulfanyl-Substituted Butadienes, and Functionalized Thiophenes Starting from Polypyridinium Salts

Hexachlorobuta-1,3-diene reacted with DMAP, 4-(pyrrolidin-1-yl)pyridine, 4-(morpholin-1-yl)pyridine, and 4-amino-pyridine to 1,1',1,1'-tetrakis-(2,3-dichlorobuta-1,3-diene-1,1,4,4-tetrayl)pyridinium salts, respectively. Except for the 4-amino derivative, these salts were converted into 1,1'-bis-(1,2,3,4-tetrachloro-buta-1,3-diene-1,4-diyl)pyridinium salts on treatment with bromine or iodine in acetic acid or water. On reaction with thiolates, tetrakis-sulfanyl-substituted [3]-cumulenes were obtained, whereas treatment with sulfur yielded 1,1'-bis-(2,3-dichloro-thiophene-1,4-diyl)pyridinium salts. Sodium disulfide gave 1,1'-bis-(2,3-dichloro-1,4-dimercaptobuta-1,3-diene-1,4-diyl)pyridinium salts.