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Electrochemical study of the mechanism of dimethylsulfoxide electrooxidation on a platinum electrode in acidic and alkaline solutions is carried out. On the stationary anodic polarization curves taken in acidic and alkaline dimethylsulfoxide solutions, the oxidation currents preceded those measured in the supporting electrolyte. By the analyzing of linear segments of anodic voltammograms, the coefficients of the Tafel equation are determined. This allowed choosing the current density range and conditions for the dimethylsulfoxide electrooxidation on the platinum electrode. The electrolysis was carried out at controlled current density in electrolyzers both with unseparated compartments and the anodic and cathodic compartments separated with MK-40, MA-40 membranes and a MF-4SK fluoropolymer sulfocationite membrane. The high electrical conductivity and selectivity of the membranes provided good performance of the electrolysis process and obtaining of high-purity final product. Raman spectroscopy and gas chromatography–mass spectrometry confirmed that the products of dimethylsulfoxide electrooxidation in the acidic solution are dimethylsulfone and dimethylsulfoxide; in alkaline solution, the dimethyl sulfone and sodium methanesulfonate. The method of quantum-chemical calculations showed good adsorption of dimethylsulfoxide molecules at platinum within the frames of the cluster model. It is shown that the dimethylsulfoxide formation at the platinum electrode surface at high current densities occurs by the radical-ion mechanism, involving breaking of the C–S bond. Based on the experimental results obtained, a scheme for the dimethylsulfoxide electrochemical oxidation at platinum is proposed. [ABSTRACT FROM AUTHOR]

a comparative assessment of dimethylsulfoxide and dimethylsulfone adsorption on a smooth platinum electrode in acidic medium in the region of anode potentials is presented. The adsorption isotherms in the "hydrogen" potential range, depending on the dimethylsulfoxide and dimethylsulfone concentration, are S-shaped. At the adsorbate concentrations in the solution exceeding 0.1 M, the surface coverage with dimethylsulfoxide and dimethylsulfone is nearly the same and changes but slightly. A significant difference in the adsorption characteristics of dimethylsulfoxide and dimethylsulfone in the potential region of oxygen adsorption is found. According to the Pt-electrode surface coverage with oxygen in the presence of the test substances, it was concluded that the value of the dimethylsulfoxide and dimethylsulfone adsorption is maximal only when their bulk concentration is higher than 0.1 M, here the oxygen surface coverage in the presence of dimethylsulfone exceeds that in the background solution. [ABSTRACT FROM AUTHOR]

Dimethylsulfone (DMSO2), a small organic molecule, was observed to induce the alignment of poly(3,4-ethylenedioxythiophene): poly(4-styrenesulfonate) (PEDOT:PSS) via in-situ crystallization in PEDOT:PSS mixture, which was verified by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). A chemically stable dopant, DMSO2, remarkably raised the electrical conductivity of the PEDOT:PSS film, which was fabricated from pre-mixed solution of PEDOT:PSS and DMSO2, up to 1080 S/cm, and more importantly, such a PEDOT:PSS film showed a long-term humidity stability and it retained near 90% electric conductivity after 60 days, suggesting DMSO2 is promising for an eco-friendly alternative to replace dimethyl sulfoxide (DMSO), ethylene glycol (EG) and various acids dopants that have been widely employed to dope and post-treat PEDOT:PSS. Pairwise interaction energies and free energy of solvation between PEDOT:PSS and DMSO2 were calculated by first-principles and molecular mechanics, respectively, revealing the mechanism of DMSO2 in enhancing the electrical conductivity.

Methyl sulfur compounds are a rich source of environmental sulfur for microorganisms, but their use requires redox systems. The bacterial sfn and msu operons contain two-component flavin-dependent monooxygenases for dimethylsulfone (DMSO 2) assimilation: SfnG converts DMSO 2 to methanesulfinate (MSI–), and MsuD converts methanesulfonate (MS–) to sulfite. However, the enzymatic oxidation of MSI– to MS– has not been demonstrated, and the function of the last enzyme of the msu operon (MsuC) is unresolved. We employed crystallographic and biochemical studies to identify the function of MsuC from Pseudomonas fluorescens. The crystal structure of MsuC adopts the acyl-CoA dehydrogenase fold with putative binding sites for flavin and MSI–, and functional assays of MsuC in the presence of its oxidoreductase MsuE, FMN, and NADH confirm the enzymatic generation of MS–. These studies reveal that MsuC converts MSI– to MS– in sulfite biosynthesis from DMSO 2. • The crystal structure of MsuC from P. fluorescens was solved at 1.69 Å resolution. • MsuC adopts the acyl-CoA dehydrogenase fold and forms a tetramer. • Functional assays confirm MsuC is a two-component flavin-dependent monooxygenase. • Molecular docking identifies a putative methanesulfinate binding site. • Methanesulfinate is enzymatically oxidized in sulfur assimilation from DMSO 2. [ABSTRACT FROM AUTHOR]

Dimethylsulfone reacts in the binary superacidic systems XF/MF5 (X = H, D; M = As, Sb) under the formation of the corresponding salts of the type [(CH3)2SO(OX)]+[MF6]–. The salts are characterized by low temperature vibrational spectroscopy. In case of [(CH3)2SO(OH)]+[SbF6]– a single‐crystal X‐ray structure analysis is reported. The salt crystallizes in the orthorhombic space group Pbca with eight formula units per unit cell [a = 10.3281(3) Å, b = 12.2111(4) Å, c = 13.9593(4) Å]. The experimental results are discussed together with quantum chemical calculations on the PBE1PBE/6‐311G++(3pd,3df) level of theory. [ABSTRACT FROM AUTHOR]

The biochemical pathway through which sulfur may be assimilated from dimethylsulfide (DMS) is proposed to proceed via oxidation of DMS to dimethylsulfoxide (DMSO) and subsequent conversion of DMSO to dimethylsulfone (DMSO 2 ). Analogous chemical oxidation processes involving biogenic DMS in the atmosphere result in the deposition of DMSO 2 into the terrestrial environment. Elucidating the enzymatic pathways that involve DMSO 2 contribute to our understanding of the global sulfur cycle. Dimethylsulfone monooxygenase SfnG and flavin mononucleotide (FMN) reductase MsuE from the genome of the aerobic soil bacterium Pseudomonas fluorescens Pf0-1 were produced in Escherichia coli , purified, and biochemically characterized. The enzyme MsuE functions as a reduced nicotinamide adenine dinucleotide (NADH)-dependent FMN reductase with apparent steady state kinetic parameters of K m = 69 μM and k cat / K m = 9 min −1 μM −1 using NADH as the variable substrate, and K m = 8 μM and k cat / K m = 105 min −1 μM −1 using FMN as the variable substrate. The enzyme SfnG functions as a flavoprotein monooxygenase and converts DMSO 2 to methanesulfinate in the presence of FMN, NADH, and MsuE, as evidenced by 1 H and 13 C nuclear magnetic resonance (NMR) spectroscopy. The results suggest that methanesulfinate is a biochemical intermediate in sulfur assimilation. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, we provide a dielectric study on dimethylsulfone (DMSO2) solutions in water and dimethylsulfoxide (DMSO) in the frequency range from 100MHz to 50GHz and for temperatures from 298.15 to 318.15K. The dielectric data are parametrized utilizing a Cole–Davidson spectral function, which presumes an unsymmetrical relaxation time distribution. The conductivity contribution to the total relaxation must be taken into account only in an aqueous solution of DMSO2. The concentration dependent static dielectric constant (εS), relaxation time (τ) and relaxation strength (Δε) of these solutions have been determined. [Copyright &y& Elsevier]

Abstract: In this paper the densities and enthalpies of solution of dimethylsulfone (DMSO2) in dimethylsulfoxide (DMSO) and DMSO/water equimolar mixture have been measured over available concentration range (up to about 1molkg−1). Densities of solutions and apparent molar volumes were determined over the 293.15–323.15K temperature range. In DMSO2–DMSO–water system the strongest interaction between DMSO and water molecules leads to the increase of partial molar volumes for DMSO2. It was shown that the competitive intermolecular interactions are responsible for the observed phenomena. Solution enthalpies of DMSO2 in the above mentioned solvents and the enthalpies of transfer of DMSO2 from water to DMSO and DMSO/water mixture have been calculated. The obtained results confirm that the endothermal process of sulfone crystalline lattice decomposition predominates during the dissolution of sulfones. With the transfer of DMSO2 from water to DMSO and mixed solvent the endothermic increase of transfer enthalpies takes place. [Copyright &y& Elsevier]

Raman and IR absorption spectra were studied and molecular relaxation characteristics of vibrations of the anion and solvent were calculated for an xLiNO-(1 - x)(CH)SO system ( x = 0.1, 0.2, 0.3, 0.4 M). It was found that it is impossible to increase the concentration of free ions involved in charge transfer in such a system by either increasing the temperature or changing the concentration composition in the studied range of x. [ABSTRACT FROM AUTHOR]

Aqueous solutions of dimethylsulfone (DMSO2) and diethylsulfone (DESO2) are studied by means of densimetry, surface tension, and calorimetry. The solution densities are defined and the apparent and partial molar volumes of DMSO2 and DESO2 are calculated in the temperature range of 293.15-323.15 K. It is revealed that in both cases the increase of sulfone concentration leads to the reduction of the surface tension. This is more expressed in the case of DESO2 than in the extension of the sulfone hydrocarbon chain. The calorimetric studies show that the dissolution enthalpies of DMSO2 and DESO2 do not differ substantially from one another; in both cases the dissolution of crystalline sulfones makes a crucial contribution to the enthalpy of dissolution values [ABSTRACT FROM AUTHOR]

Abstract: The mild catalytic oxidation of dimethylsulfoxide (DMSO) into biodegradable dimethylsulfone is proposed as an efficient pretreatment of wastewaters subjected to biological treatment processes. A SiO2–TiO2 mesoporous xerogel prepared by a non-hydrolytic route, as well as titanium silicalite TS-1 showed very good activity and stability in the catalytic oxidation of DMSO with H2O2 in dilute aqueous solution, at room temperature. [Copyright &y& Elsevier]

An effective method for removing dimethylsulfoxide (DMSO) from wastewater, based on the mild selective catalytic sulfoxidation with H2O2, is proposed in this study. The catalysts are W-containing layered double hydroxides (LDH), and they were obtained by ionic exchange of the nitrate anions from MAl-LDH precursors (M=Mg2+ or Zn2+) with both and species. Results of X-ray diffraction (XRD), N2 adsorption, thermal gravimetric analysis (TGA), diffuse reflectance ultraviolet spectroscopy (DRUV) and Raman spectroscopy confirmed the formation of the W-oxospecies inside the interlayer space and the modification of the textural properties upon the exchange process. All catalysts showed very good activity and stability in the DMSO conversion into dimethylsulfone with dilute H2O2 aqueous solution, at low temperatures (20–50°C). The efficiency of the H2O2 was higher than 95% and the behaviour of the water as solvent was very close to that of the organic solvents (ethanol, acetonitrile, 1,4-dioxane). [Copyright &y& Elsevier]

Abstract: This paper presents a study of the aluminum deposition processes in dimethylsulfone (DMSO2)-based electrolytes. The electrical conductivities of the AlCl3/DMSO2 electrolytes were investigated as a function of temperature (70–180 °C) and molar ratio of AlCl3 to DMSO2 (from 0.1:1 to 0.8:1). The results show that the temperature-dependent conductivities of the electrolytes fit well with the Vogel–Tamman–Fulcher (VTF) equation. The optimum operating conditions for the electrodeposition of aluminum from AlCl3/DMSO2 electrolytes were determined based on the studies of the effects of current density, electrolyte temperature and the molar ratio of AlCl3 to DMSO2 on the quality of the deposited coatings. Dense, bright and adherent aluminum coatings were obtained in AlCl3/DMSO2 electrolytes over a wide range of temperatures (110–150 °C) and current densities (5 to 20 A dm−2). The preliminary results from Al refining experiments showed that Al alloy can be purified via electrolysis in 0.2:1 AlCl3/DMSO2 at 130 °C with a current density of 10 A dm−2. [Copyright &y& Elsevier]

Volatile organic sulfur compounds (VOSCs) play a major role in the global sulfur cycle. Two components, dimethyl sulfide (DMS) and methanethiol (MT) are formed in large amounts by living systems (e.g. algae, bacteria, plants), particularly in marine environments. A major route to DMS is by action of a lyase enzyme on dimethylsulfoniopropionate (DMSP). DMSP has other roles, for instance as an osmoprotectant and cryoprotectant. Demethiolation of DMSP and other materials leads to MT. A major transport process is release of DMS from the oceans to the atmosphere. Oxidation of DMS in the atmosphere by hydroxyl and nitrate radicals produces many degradation products including CO2, COS, dimethyl sulfoxide, dimethyl sulfone, organic oxyacids of sulfur, and sulfate. These materials also have roles in biotic processes and there are complex metabolic interrelationships between some of them. This review emphasizes the chemical reactions of the organic sulfur cycle. For biotic reactions, details of relevant enzymes are provided when possible. [Copyright &y& Elsevier]

The reconstruction of angular distributions from two-dimensional (2D) magnetic resonance spectra of powders is described. The analysis involves no model assumptions and is applicable to 2D exchange NMR as well as 2D nutation exchange NQR. The proposed method is based on the constrained analysis of selected dominant ridges of a 2D powder spectrum. Practical applications of the proposed technique are demonstrated with experimental 13C 2D exchange NMR spectrum of dimethylsulfone and calculated 35Cl 2D nutation exchange NQR spectra of chloral hydrate. Rotational angle distributions for methyl groups in dimethylsulfone and CCl3 group in chloral hydrate have been found. The chemical shift anisotropy of 13C in dimethylsulfone was determined with high accuracy from 2D exchange NMR powder spectra. [Copyright &y& Elsevier]

Novel methylotrophic Arthrobacter and Hyphomicrobium species are described. Constitutive membrane-associated dimethylsulfone- and dimethylsulfoxide-reductases were found in Arthrobacter methylotrophus strain TGA and Hyphomicrobium sulfonivorans strain S1. Enzyme activities increased during growth with dimethylsulfone or dimethylsulfoxide, respectively, and different ratios of activity with different growth substrates indicated that they are separate enzymes. SDS-PAGE showed some membrane-associated polypeptides to be enhanced during growth with dimethylsulfone (54 kDa in H. sulfonivorans, 21–24 kDa, 54 kDa and 80 kDa in A. methylotrophus). Western blotting with anti-dimethylsulfoxide-reductase antibody showed cross-reaction with 54- and 21-kDa polypeptides in A. methylotrophus. All strains contained rhodanese and sulfur oxygenase after growth with dimethylsulfone. Sulfite was oxidized in the Arthrobacter species by APS reductase and sulfite dehydrogenase. H. sulfonivorans oxidized sulfite with APS reductase, which is unusual for an α-proteobacterium. The Arthrobacter species were distinguished from each other and from other Arthrobacter and Micrococcus species by 16S rRNA gene sequence analysis. The menaquinone and fatty acid profiles of the Arthrobacter species were similar. Their peptidoglycan structures were L-Lys–L-Ser–L-Thr–L-Ala for A. sulfonivorans and L-Lys–L-Ala2–4 for A. methylotrophus. H. sulfonivorans exhibited gross morphology typical for Hyphomicrobium, but possessed helically twisted prosthecae. 16S rRNA gene sequence analysis showed it to be distinct from all the other Hyphomicrobium, Filomicrobium and Pedomicrobium species sequenced to date. Formal descriptions of the new species are given. [ABSTRACT FROM AUTHOR]

Dimethylsulfone is a major product of the chemical oxidation in the atmosphere of the principal biogenic sulfur gas, dimethylsulfide, but no studies have been reported on the mechanisms for its microbiological degradation. Three novel strains of bacteria have been isolated from enrichment cultures provided with dimethylsulfone as the only carbon and energy substrate. These are novel facultatively methylotrophic species of Hyphomicrobium and Arthrobacter, capable of growth on a range of one-carbon substrates. Cell-free extracts contained activities of enzymes necessary for a reductive/oxidative pathway for dimethylsulfone degradation: membrane-bound-dimethylsulfone and dimethylsulfoxide reductases, dimethylsulfide monooxygenase, and methanethiol oxidase. Enzymatic evidence is also presented for the subsequent oxidation of formaldehyde by formaldehyde and formate dehydrogenases in the Hyphomicrobium strain and by a dissimilatory ribulose monophosphate cycle in the Arthrobacter strains. The strains also grew on dimethylsulfoxide and dimethylsulfide, and dimethylsulfide-grown bacteria oxidized dimethylsulfide and dimethylsulfoxide but not dimethylsulfone. Formaldehyde assimilation was effected in the Hyphomicrobium strain by the serine pathway, but enzymes of the ribulose monophosphate cycle for formaldehyde assimilation were present in the Arthrobacter strains grown on dimethylsulfone. In contrast, one of the Arthrobacter strains was shown to switch to the serine pathway during growth on methanol. Growth yields on dimethylsulfone and formaldehyde were consistent with the occurrence of the serine pathway in Hyphomicrobium strain S1 and the ribulose monophosphate cycle in Arthrobacter strain TGA, and with the proposed reductive pathway for dimethylsulfone degradation in both. [ABSTRACT FROM AUTHOR]