Organosulfur Groups Research Articles

Anchoring Pd-nanoparticles on dithiocarbamate- functionalized SBA-15 for hydrogen generation from formic acid

Hydrogen (H2) generation from natural biological metabolic products has remained a huge challenge for the energy arena. However, designing a catalytic system with complementary properties including high surface area, high loading, and easy separation offers a promising route for efficient utilization of nanoreactors for prospective H2 suppliers to a fuel cell. Herein, selective dehydrogenation of formic acid (FA) as a natural biological metabolic product to H2 and CO2 gas mixtures has been studied by supporting ultrafine palladium nanoparticles on organosulfur-functionalized SBA-15 nanoreactor under ultrasonic irradiation. The effects of the porous structure as a nanoreactor, and organosulfur groups, which presented around the Pd due to their prominent roles in anchoring and stabilizing of Pd NPs, studied as a superior catalyst for selective dehydrogenation of FA. Whole catalytic systems were utilized in ultrasonic irradiation in the absence of additives to provide excellent TOF/TON values. It was found that propose catalyst is a greener, recyclable, and more suitable option for the large-scale application and provide some new insights into stabilization of ultra-fine metal nanoparticle for a variety of applications.

Enhanced Li Ion Storage Performances of Carbon Black by Introducing Organosulfur Groups on Surface

Enhanced Li Ion Storage Performances of Carbon Black by Introducing Organosulfur Groups on Surface

Nickel-Catalyzed Regioselective Cleavage of C(sp(2))-S Bonds: Method for the Synthesis of Tri- and Tetrasubstituted Alkenes.

We describe here an efficient route for the synthesis of (Z)-vinylic sulfides 3 via the highly regio- and stereoselective coupling of (Z)-1,2-bis(aryl(alkyl)thio)alkenes and Grignard reagents over a Ni catalyst under mild conditions. (Z)-Vinylic sulfides 3 are important intermediates in the synthesis of tri- and tetrasubstituted alkenes that are important construction blocks for drugs and natural products. The directing organosulfur groups (SR) can be converted to diaryl(alkyl) disulfides (RSSR) using H2O2 as oxidant, hence avoiding the waste of sulfur resources. The protocol provides a general method that is highly regio- and stereoselective for the synthesis of a diversity of tri- and tetrasubstituted alkenes.

Biogenic volatile compounds of activated sludge and their application for metal bioremediation

Heavy metals pollution is nowadays one of the most important environmental concerns. This paper illustrates the employment of the biogenic volatile compounds generated during the aerobic growth of activated sludge on raw domestic wastewater for heavy metals removal. Most of the tested metals even as individual or mixed metal species (Co, Cu, Cd, Fe, Hg, Ni, Mn, Pb and Zn) were potentially transformed into insoluble precipitates and then separated out of their solutions. The Fourier-transform infrared (FTIR) analysis has identified some organosulfur groups (thiol, disulfide and thiocarbonyl), in addition to amine group in the metal precipitates. This study highlighted the application of the microbial volatile metabolites for heavy metals bioremediation in a powerful, cost effective and eco-friendly bioprocess.

Self-Patterned Mixed Phospholipid Monolayers for the Spatially Selective Deposition of Metals

Metal-reactive organosulfur groups were patterned onto mica and silicon surfaces by dewetting instabilities during the Langmuir-Blodgett (LB) deposition of phase-separated mixed phospholipid monolayers. Monolayers were formed from binary mixtures of dipalmitoylphosphatidylcholine (DPPC), dilauroylphosphatidylcholine (DLPC), and their ω-methyldisulfide-dialkylphosphatidylcholine analogues, DSDPPC and DSDLPC. Patterns of highly parallel stripes of condensed DPPC or DSDPPC, protruding by 0.7-0.9 nm from a fluid matrix of DLPC or DSDLPC, were observed over areas extending at least 30 × 30 μm(2) in the LB films. The average stripe width varied from ca. 150 to 500 nm, depending on the lipid composition and deposition pressure. X-ray photoelectron spectroscopy confirmed that the phospholipid-monolayer-bound methydisulfides react with Au vapor to form a gold-thiolate species. The adsorption of thermally evaporated Au, Ag, and Cu onto DSDPPC/DLPC and DPPC/DSDLPC patterns was investigated by field emission gun scanning electron microscopy (FEGSEM) and atomic force microscopy (AFM). A change in phase contrast is observed in FEGSEM and AFM over the methyldisulfide-functionalized areas following metal deposition due to metal-thiolate bond formation. An increase in step height between the DSDPPC stripes and nonfunctionalized DLPC background following metal deposition, as well as the resistance of the metal-coated DSDPPC or DSDLPC regions to detergent extraction from the surface, attest to a selective metallization of the pattern. Our results indicate that the preferential adsorption of vapor-deposited metal onto the ω-methyldisulfide-terminated phase occurs at submonolayer coverages. The chemical reactivity exhibited by the organosulfur-modified phospholipid LB films make these templates potentially interesting for the fabrication of solid-supported patterns of metal nanostructures.

Transition-metal-catalyzed synthesis of organosulfur compounds

Abstract Rhodium complexes are efficient catalysts for the synthesis of organosulfur compounds. They catalyze the addition reaction of organosulfur groups to unsaturated compounds, the substitution of C-H with organosulfur groups, and single-bond metathesis reactions. They cleave S-S bonds and transfer the organosulfur groups to various organic and inorganic molecules, including alkynes, allenes, disulfides, sulfur, isonitriles, imines, diphosphines, thiophosphinites, hydrogen, 1-alkylthio-1-alkynes, thioesters, and allyl sulfides.

Synthesis, characterization and catalytic activity of ordered macroporous silicas functionalized with organosulfur groups

Hybrid three-dimensionally ordered macroporous (3DOM) SiO 2–SO 3H materials with different S/Si ratio have been prepared by colloidal crystal templating method. The process involved preparation of 3DOM SiO 2–SH materials by co-condensation of (3-mercaptopropyl)triethoxysilane and tetraethoxysilane via sol–gel transformation, and following oxidation of –SH group to –SO 3H group by H 2O 2. Materials were characterized by scanning electron microscopy (SEM), Fourier transform infra-red spectrometer (FTIR), thermogravimetric analysis (TGA), and nitrogen adsorption measurement. SEM observation shows that the macropores are highly ordered with a typical “surface-templated” structure. The surface area of 3DOM SiO 2–SH material is 25.1 m 2/g and SiO 2–SO 3H material is 18.6 m 2/g. Catalytic activity test shows that 3DOM SiO 2–SO 3H materials possess a high activity for the esterification of acetic acid and n-butanol, and the activity is increased with the amount of sulfur in the materials. This study provided significant results for developing new application of 3DOM materials.

Antimicrobial Properties of Organosulfur Anti-Infectives: A Review of Patent Literature 1999-2005

The number of organosulfur compounds being patented has been growing. A wide variety of these organosulfur compounds, whether naturally occurring or synthetic, exhibit antibacterial properties. Mechanistically, organosulfur groups can act as metal chelators, powerful nucleophiles or electrophiles depending on the local environment in which a given reaction occurs. In this review of the patent literature from 1999-2005, the reliance of these compounds on the reaction of the sulfur moiety with its biological target(s) will be discussed with regards to activity, specificity, and antimicrobial spectrum.

FUEL INSTABILITY STUDIES: THE CHEMICAL VALIDATION OF ASTM METHOD D5304

The current ASTM (D5304) procedure for determining storage stability involves rather drastic conditions, namely, 16 hours at 90°C and under 100 psig of oxygen. These mandated test conditions give rise to the question, “Does the reaction conditions induce chemical instability, or is it an accurate measure of the true instability process?” Several organo-sulfur functional groups are known to be present in petroleum derived fuels. Thiophenes, benzothiophenes, sulfides, disulfides, and trace amounts of thiols are the organo-sulfur compounds most prevalent. The reaction of organo-sulfur compounds under the ASTM reaction conditions have not been investigated. The purpose of the present research is to determine if the ASTM reaction conditions induce a reaction in an otherwise stable fuel matrix.

Organosulfur Functionality as an Alternative Enantiocontrollable Coordinating Element in Chiral Phosphine Ligands for Palladium-Catalyzed Asymmetric Allylic Alkylations

Abstract The synthesis of (S)-proline-derived phosphines bearing organosulfur groups and the use of them as chiral ligands in palladium-catalyzed asymmetric allylic alkylations were accomplished successfully. The mechanism is discussed on the basis of the stereochemical results, presumably by participation of organosulfur groups as alternative enantiocontrollable coordinating elements.

Stereochemistry of highly selective transition metal or Lewis acid-catalyzed asymmetric reactions

Recent progress of our studies on catalytic asymmetric synthesis is reviewed focused on transition metal-catalyzed intramolecular asymmetric reactions using chiral organo-sulfur groups as main chiral auxiliaries such as asymmetric vinyl-cyclopropane-cyclopentene rearrangements and intramolecular asymmetric metallo-ene reactions, Lewis acid-catalyzed intramolecular asymmetric ene reactions with chiral sulfinyl groups, and palladium-catalyzed intramolecular asymmetric allylations via chiral enamines.

Detection of growth sites in and protomer pools for the sheath of Methanospirillum hungatei GP1 by use of constituent organosulfur and immunogold labeling.

Methanospirillum hungatei GP1 integrated approximately 9% of cellular [35S]cysteine into its sheath. Autoradiography of sodium dodecyl sulfate-polyacrylamide gels revealed that [35S]cysteine was confined to the proteins released by the sodium dodecyl sulfate-beta-mercaptoethanol-EDTA solubilization method (G. Southam and T. J. Beveridge, J. Bacteriol. 173:6213-6222, 1991) and was not present in the proteins released by treatment with phenol (G. Southam and T. J. Beveridge, J. Bacteriol. 174:935-946, 1992). Limited labeling of exposed sulfhydryl groups on hoops produced from sheath material suggested that most organosulfur groups occur within hoops and therefore help contribute to resilience. Electron microscopic autoradiography demonstrated that sheath growth, which is most active at the sites of cell division (spacer region), occurs through the de novo development of hoops. For growth to occur in the spacer region, sheath precursors must transverse several periodic envelope layers, including the cell wall (a single layer) and the various lamellae of the spacer plug (T. J. Beveridge, G. D. Sprott, and P. Whippey, J. Bacteriol. 173:130-140, 1991).

キラル有機硫黄グループを主な不斉修飾剤とする高エナンチオ選択的不斉反応

キラル有機硫黄グループを主な不斉修飾剤とする高エナンチオ選択的不斉反応