Cyclic Polysulfides Research Articles

Термальные сульфидные воды Баргузинской долины (Республика Бурятия)

Abstract. Relevance. Hydrogen sulfide mineral waters are widely used in spa treatment. The therapeutic effect of exposure to hot water procedures gives positive results in chronic pathologies of the musculoskeletal system, gastroenterology, as well as in other areas of prevention and rehabilitation of human health, where hydrogen sulfide is considered an important therapeutic component. The aim of the work. Investigation of the hydrochemical and microbiological composition of thermal hydrogen sulfide waters of Umkhey, Kuchiger, Alla springs of the Barguzin Valley of the Republic of Buryatia. Materials and methods. The composition of sulfur-containing compounds in sources, which by their composition belong to the nitric thermal siliceous waters of the Baikal hydromineral region, where the accumulation of chemical components is facilitated by an alkaline environment and elevated temperature, has been studied using hydrochemical analysis, mass spectrometry and high-performance liquid chromatography. Results. The conducted studies have shown that in addition to sulfides and sulfates, sulfites, thiosulfates, mineral water contains elemental and polysulfide sulfur, cyclic polynuclear organosulfur compounds and cyclic polysulfides. These compounds can exhibit high balneological activity due to their better permeability through the skin at high temperatures. The composition of the microbial community of water and bottom sediments has been studied, which is represented by various taxonomic groups, where the chemolithotrophic bacteria Thiobacillus, Thermodesulfovibrio, Geobacter and Gallionella are the dominant group. The microbial community in thermal springs is involved in the transformation of chemicals, the formation and consumption of gases, in biogeochemical cycles of sulfur, the formation of the chemical composition and therapeutic factor of waters and sediments. Conclusions. The presence of organic sulfanes simultaneously with elemental sulfur and hydrogen sulfide suggests that they are active balneological components of thermal hydrogen sulfide mineral waters. The microbial community of water and bottom sediments in thermal springs is involved in the transformation of chemicals and the formation of the chemical composition and therapeutic factor of waters and bottom sediments.

Reactivity of hydrogen sulfide toward organic compounds with sulfur-sulfur bonds

The presence of organic molecules containing sulfur-sulfur bonds was documented in the water columns and sediments of the natural aquatic systems as well as in fossil fuels. These compounds range from small molecules of volatile organic compounds to polysulfide cross-linked macromolecules in the sediments. While processes leading to formation of these compounds were intensively studied during the last decades, kinetics and mechanisms of reactions which lead to their decomposition are poorly understood. In this work, the kinetics and products of the reactions of dimethyl disulfide, dimethyl trisulfide, and cyclic polysulfide lenthionine (1,2,3,5,6-pentathiepane) with hydrogen sulfide at the environmental pH and temperature ranges were studied. It was shown that at pH ≥ 5, the reaction of bisulfide anion (HS–) rather than that of hydrogen sulfide controls the overall reaction rates. The activation energy and the order of the reaction with respect to bisulfide anion is dimethyl disulfide– < dimethyl trisulfide < lenthionine, while the order of the reaction with respect to organosulfur compounds is lenthionine < dimethyl trisulfide < dimethyl disulfide. The obtained results suggest that bisulfide anion is responsible for fast decomposition of organosulfur compounds in aphotic natural aquatic systems. This observation leads to the conclusion that sulfurization of sedimentary organic matter during the early diagenesis is not an unidirectional but a dynamic process, and concentrations of organic compounds with sulfur-sulfur bonds are controlled by the polysulfide to sulfide sulfur concentrations ratio in the sedimentary pore waters. In addition, the cyclic polysulfides were shown to be more stable than their linear analogs that results in preferential preservation of these compounds during the maturation process.

Synthesis of 1,1,4,4-tetra-aryl-1,3-butadienes possessing sulfur substituents at 2,3-positions via dithiol intermediates and their characteristic electrochromic behaviors

Abstract Synthesis and reactions of 2,3-dimercapto-1,1,4,4-tetra-aryl-1,3-butadienes as versatile intermediates for sulfur-containing 1,1,4,4-tetra-aryl-1,3-butadiene derivatives are described. The dithiols were prepared from cyclic polysulfides and their structures were characterized by single-crystal X-ray diffraction analyses. Both cyclic dithioacetals and acyclic S,S′-dimethyl derivatives were prepared by facile reactions of the corresponding dithiols. The acyclic sulfur-substituted dienes exhibited electrochromic behavior in which the solution turned from colorless to dark purple under an external electric field above a potential of 0.3 V vs Fc/Fc+.

Biosynthesis, behavior and fate of volatile organic sulfide in Lentinus edodes (Berk.) upon hot-air drying treatment

This study elucidated the biosynthesis and changing behaviors of organic sulfide in shiitake mushrooms upon hot-air drying treatment. The changes of aw, moisture migration, contours of taste and flavor, organic sulfide, and 4 key enzyme activities were monitored throughout three drying procedures (CT/ST1/ST2). Results showed that drying rate was related to the moisture migration. Key enzymes of γ-GTase, ASFase and CS lyase were heat-resistant proteases, while C-Dase exhibited low thermal stability with the activity decreased during treatment. A total of 17 organic sulfides were identified and PLS analyses suggested 6 cyclic polysulfides were formed by C-Dase desulfurization, while 5 thioethers generation were related to the thermal cleavage of direct precursors (straight-chain di/tris/tetrasulfonyl esters) and Maillard reaction. These results indicated that ST2 drying procedures had a positive effect on the formation of cyclic polysulfides at the end of drying pried and the achievement of premium flavor qualities.

Thioacyl-Transfer Ring-Expansion Polymerization of Thiiranes Based on a Cyclic Dithiocarbamate Initiator

We report the novel thioacyl-transfer ring-expansion polymerization (REP) of thiiranes, using 3H-benzothiazol-2-thione (BTT) as the cyclic dithiocarbamate initiator and tetrabutylammonium chloride (TBAC) as the catalyst. REP proceeded in a controlled manner to produce cyclic polysulfides with a narrow Mw/Mn of 1.1 and whose cyclic structures were confirmed by MALDI-TOF mass spectrometry. Time-course studies revealed unique sigmoidal profiles due to the stable five-membered cyclic structure of the BTT initiator. The GPC curves were analyzed by the Gaussian fitting method, which revealed that the cyclic polymers are accompanied by another fraction with nearly twice the molecular weight of the main product due to ring-crossover reactions between cyclic polysulfides during REP. The BTT-initiated cyclic polysulfides produced in this manner act as macroinitiators for the REP of thiiranes, highlighting the living characteristics of the BTT-initiated REP developed herein. Post-polymerization further enabled the preparation of cyclic block copolymers with different combinations of thiiranes.

Intermolecular cyclic polysulfides as cathode materials for rechargeable lithium batteries

Intermolecular cyclic polysulfides are synthesized and used as cathode materials in rechargeable lithium batteries. Their intriguing redox reactions are revealed.

Controlled ring‐expansion polymerization of thiiranes based on cyclic aromatic thiourethane initiator

ABSTRACTRing‐expansion polymerization (REP) of thiiranes was investigated using 3H‐benzothiazol‐2‐one (BT) as the cyclic aromatic thiourethane initiator in the presence of tetrabutylammonium chloride (TBAC) catalyst. The polymerization proceeded in a well‐controlled manner to afford cyclic polysulfides with one BT moiety per macrocycle, as confirmed by MALDI‐TOF MS spectroscopy. Differential scanning calorimetry (DSC) measurement of the obtained cyclic polysulfides revealed slight decrease in the glass‐transition temperature as the increase in the molecular weight, supporting the cyclic topology of the products. Postpolymerization of thiiranes using the BT‐initiated cyclic polysulfide as the macroinitiator afforded the ring‐expanded product while maintaining the narrow polydispersity and well‐defined cyclic structure, which enabled precise synthesis of cyclic block copolymer with different thiirane combination. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2442–2449

Organic and Coordination Chemistry of 1,2,4‐Trithiolanes

The review is aimed in summarizing the most important aspects of the chemistry of 1,2,4‐trithiolanes, which form a relevant class of cyclic polysulfides abundant in nature. Some of them were identified as components of Lenthinus edodes (shiitaki mushrooms) extracts as well as of Parkia speciosa (stink bean), which are well known in Asian cuisine. In addition, they determine the flavor of boiled beef and roasted chicken. Thermal decomposition of 1,2,4‐trithiolanes, either in solution or in the gas phase, results in [3+2]‐cycloelimination leading to the release of reactive thiocarbonyl S‐sulfides existing in equilibrium with sulfur‐rich, three‐membered dithiiranes. Both, 1,2,4‐trithiolanes and the products of their decomposition react with low‐valent platinum and iron compounds forming the corresponding sulfur‐metal complexes. For example, iron‐sulfur clusters formed in these reactions are of interest as structural models of [Fe,Fe]‐hydrogenase mimics.

Polysulfide Reduction and Oxidation at MoS2, WS2 and Cu-Doped MoS2 Thin Film Electrodes

The sluggish kinetics of cyclic polysulfide electrochemistry, where sulfur species typically range from S22− to S62−, presents a challenge in several common electrochemical systems. Recently, transition metal dichalcogenides such as WS2 and MoS2 have been proposed for catalysis of polysulfide oxidation-reduction. Here electrodeposited WS2, MoS2, and Cu-doped MoS2 thin films are tested for 24 h cycling in an electrolyte containing 1.8 M Na2Sx + 1.0 M NaOH. Although their initial catalytic activity is high, electrodeposited WS2 films delaminated after ∼4 h. The initial catalytic activity of MoS2 films is also high, but MoS2 gradually transforms to Mo2S3 during 24 h of polysulfide oxidation-reduction cycling, as shown by X-ray diffraction (XRD), cross-sectional scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The best results were obtained for Cu-doped MoS2, which exhibited both high catalytic activity and stable polarization curves during 24 h of potential cycling. To the best of the authors’ knowledge, this is the first report of MoS2 stabilization during cyclic polysulfide electrochemistry through incorporation of a metal dopant into MoS2.

Anti–odor activity of milk kefir on organosulphur polysulfide cyclic compounds in petai (parkia speciosa hassk)

This study aims to assess the activity of milk kefir whey in neutralizing odor-causing cyclic polysulfide compounds in petai (Parkia speciosa Hassk.). RAL designs used to determine the optimum fermentation conditions. The data obtained were processed using SPSS 20. Results showed the characteristics of the microbes in the kefir grains include lactic acid bacteria consisting of genus Lactobacillus and yeast of the genus Candida and Saccharomyces. The optimum fermentation conditions using cow’s milk kefir grain starter obtained in the fermentation time of 24 hours at a concentration of 5% kefir grain. Whey kefir which is produced have high levels of fat, protein, carbohydrates, fiber and lactic acid respectively 1.81; 4.35; 5.59; 0.26 and 0.16%, pH 4.4; a density of 1.0628 g/mL and 7.9368 cP viscosity. Kefir milk whey actively reduced the level of petai smell significantly different at the level of α = 0.05.

Plasma-Chemical Conversion of Hydrogen Sulfide in the Atmosphere of Methane with Addition of CO2 and O2

Plasma-chemical conversion of hydrogen sulfide in the atmosphere of methane with addition of CO2 and O2 in the nonequilibrium plasma of barrier discharge is studied. The degree of hydrogen sulfide removal reaches 97 vol%. The degree of methane transformation does not exceed 14 vol%. Gaseous reaction products contain hydrogen, carbon oxides, and C2–C4 hydrocarbons. The energy consumption for the removal of hydrogen sulfide ranges from 84 to 182 eV molecule−1. The process is accompanied by the formation of deposits on the surface of reactor electrodes. The composition of deposits is studied. Organic linear and cyclic polysulfides, as well as sulfones of various structures are identified in soluble components of deposits. Based on the experimental data and the results of theoretical estimates, a radical chain reaction mechanism is proposed. It is shown that the formation of polysulfide compounds with terminal alkyl and oxygen-containing groups is provided by the reactions between atomic oxygen, SH, and alkyl radical which were formed in the initial stages of processes in the non-equilibrium plasma of barrier discharge.

Theoretical investigations on the conversions of cyclic polysulfides to acyclic polysulfide diradicals and subsequent reactions of biological interest

Sulfur is one of the most necessary biogenic elements in nature that must be assimilated by all organisms; it is an essential macronutrient for living organisms and has multiple roles in plant development. The oxidation of elemental sulfur is a complex process involving the contact of cells with sulfur particles, the oxidation of sulfur to sulfite, and the oxidation of sulfite to sulfate. To provide hypothesis concerning the most probable processes in the early states, we determined, by quantum-chemical calculations, the energies of some allotropic forms containing up to 32–40 sulfur atoms and energetics of their reactions with triplet dioxygen. The most probable reactions occurred with methylpolysulfane anions with an electron transfer to give the superoxide anion radical (and thiyls radicals) and especially the formation of peroxydic polysulfane anions. Calculations confirmed that the triplet diradical is more stable than the singlet one for acyclic polysulfide chains.

ChemInform Abstract: Natural Products Containing Hydrogen Sulfide Releasing Moieties

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Functionalization of pentagon–pentagon edges of fullerenes by cyclic polysulfides: A DFT study

We have performed a computational study to investigate the cyclosulfurization of the pentagon–pentagon (p–p) junctions in the non-IPR fullerenes C60(D3) and C70(C2v), and also Stone-Wales defective C60 fullerene. Our results indicate the exothermic character of cyclosulfurization processes which can be related to the increase of pyramidalization angle (spherical excesses) and p characters of natural hybrid orbitals of C atoms at the p–p junctions. In fact these lead to the structural strain relief and stability of the cyclosulfurization derivatives of the non-IPR fullerenes. Moreover, the cyclosulfurization reaction of p–p bonds on the C70(C2v) is more energetically favorable than that of C60(D3), due to the higher curvature of carbon sites and the larger values of the p characters of natural hybrid orbitals in the C70(C2v). On the other hand, localization of the excess electrons on the C atoms at the p–p junctions leads to the low tendency of the charged non-IPR fullerenes to cyclosulfurization process. The desulfurization pathway of the exohedral derivatives of C70(C2v) indicates that it is energetically unfavorable for the functionalized fullerenes to break into individual fullerene and sulfur molecules. HOMO–LUMO gaps almost are independent of the number of pentathiepin rings while sensitive to the type of parent fullerene.

Natural Products Containing Hydrogen Sulfide Releasing Moieties

Hydrogen sulfide (H2S) is now recognized as an important biological molecule that plays diverse roles in various (patho)physiological conditions. Endogenous H2S, or its misregulation, has been associated with a variety of aspects of human health, including diabetes, hypertension, atherosclerosis, inflammation, neurodegeneration, sepsis, and asthma. Motivated by the potential use of H2S-donating molecules as both investigative and therapeutic tools, researchers are developing new types of slow-releasing H2S donor molecules that mimic the slow, continuous H2S release characteristic of enzymatic production. In addition to synthetic H2S donors, many natural products contain functional groups well known to release sulfide. Here we provide an overview of natural products that contain such functional groups, with an emphasis on organic polysulfides, to highlight the diversity of these structures and also to outline possible areas of future research on pharmacologically relevant H2S donors derived from natural products. 1 Introduction 2 Polysulfide-Containing Natural Products 2.1 Linear Polysulfides 2.2 Cyclic Polysulfides 2.3 Epidithiodioxopiperazines 2.4 Enediyne-Containing Trisulfides 3 Leinamycin 4 Other Disulfides and Thiols Implicated in Hydrogen Sulfide Generation 5 Conclusions and Prospects

Synthesis of cyclic polysulfides: Controlled ring-expansion polymerization of cyclic tetrathioester with thiirane

We synthesized cyclic tetrathioesters containing thioester moieties at the o-position (o-CTE) and m-position (m-CTE) of an aromatic skeleton. The reaction of phenoxy propylenesulfide (PPS) with o-CTE and m-CTE was examined using tetrabutylammonium chloride as a catalyst in 1-methyl-2-pyrrolidinone, yielding the corresponding cyclic polysulfides poly[o-CTE(PPS)n] with Mn's = 37,000–54,000 at 34–61% yields and poly[m-CTE(PPS)n] with Mn's = 46,600–107,200 at 63–>99% yields. Although the molecular weights of poly[o-CTE(PPS)n] could not be controlled, those of poly[m-CTE(PPS)n] could be controlled by the feed ratios of PPS and reaction temperature. Furthermore, the glass transition temperature (Tg) and thermal decomposition temperature (Tdi) of poly[m-CTE(PPS)n] increased with decreasing molecular weights. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 857–866

Synthesis and Bioactivity of Cyclic Polysulfides

Fourteen cyclic polythiaethers, twelve of them are new compounds, were synthesized by condensation of dithiol with dichlorided compounds and then acylation. Their structures were characterized by 1 H NMR, 13 C NMR, HREIMS tech- niques. Some of the compounds were detected by X-ray. The PTP1B inhibitory activities of these compounds were tested.

Parkia speciosaHassk.: A Potential Phytomedicine

Parkia speciosa Hassk., or stink bean, is a plant indigenous to Southeast Asia. It is consumed either raw or cooked. It has been used in folk medicine to treat diabetes, hypertension, and kidney problems. It contains minerals and vitamins. It displays many beneficial properties. Its extracts from the empty pods and seeds have a high content of total polyphenol, phytosterol, and flavonoids. It demonstrates a good antioxidant activity. Its hypoglycemic effect is reported to be attributable to the presence of β-sitosterol, stigmasterol, and stigmast-4-en-3-one. The cyclic polysulfide compounds exhibit antibacterial activity, while thiazolidine-4-carboxylic acid possesses anticancer property. The pharmacological properties of the plant extract are described in this review. With ongoing research conducted on the plant extracts, Parkia speciosa has a potential to be developed as a phytomedicine.

ChemInform Abstract: Synthesis and Reaction of Cyclic Polysulfides

ChemInform Abstract: Synthesis and Reaction of Cyclic Polysulfides

ChemInform Abstract: Synthesis and Reaction of Novel Sulfur-Containing Heterocyclic Systems.

Abstract The strained alkylidene episulfides were synthesized by carbene and alkylidene carbene additions to thiocarbonyl compounds. Thermal, photochemical, and acid catalyzed reactions have been extensively investigated, and and the transition metal-promoted reaction results in the first isolation of thioallyl iron tricarbonyl complex. Germylene and zirconocene also reacted with thioketene to give metallic analogue of alkylidene episulfides, which are excellent synthetic source of a variety of cyclogermanes and stable enethiolizable thioaldehyde. Thermal sulfurization of some 1,2,3-butatriene derivatives and 1,2,3-selenadiazoles with elemental sulfur has been examined to give a variety of novel cyclic polysulfides having an unique structure. Reactive silicon and germanium species also reacted with elemental sulfur and selenium to afford cyclic metallachalcogenides.