Search results for "Sulfides"
showing 8 items of 118 documents
Heterogeneous oxidation of pyrimidine and alkyl thioethers in ionic liquids over mesoporous Ti or Ti/Ge catalysts.
2004
Heterogeneous catalytic oxidation of a series of thioethers (2-thiomethylpyrimidine, 2-thiomethyl-4,6-dimethyl-pyrimidine, 2-thiobenzylpyrimidine, 2-thiobenzyl-4,6-dimethylpyrimidine, thioanisole, and n-heptyl methyl sulfide) was performed in ionic liquids by using MCM-41 and UVM-type mesoporous catalysts containing Ti, or Ti and Ge. A range of triflate, tetrafluoroborate, trifluoroacetate, lactate and bis(trifluoromethanesulfonyl)-imide-based ionic liquids were used. The oxidations were carried out by using anhydrous hydrogen peroxide or the urea-hydrogen peroxide adduct and showed that ionic liquids are very effective solvents, achieving greater reactivity and selectivity than reactions p…
Thieme Chemistry Journals Awardees – Where Are They Now? Molybdenum(V)-Mediated Synthesis of Nonsymmetric Diaryl and Aryl Alkyl Chalcogenides
2017
Oxidative chalcogenation reaction using molybdenum(V) reagents provides fast access to a wide range of nonsymmetric aryl sulfides and selenides. The established protocol is tolerated by a variety of labile functions, protecting groups, and aromatic heterocycles. In particular, when labile moieties are present, the use of molybdenum(V) reagents provides superior yields compared to other oxidants.
Chemically Selective Imaging of Individual Bonds through Scanning Electron Energy-Loss Spectroscopy : Disulfide Bridges Linking Gold Nanoclusters
2020
As proof-of-principle of chemically selective, spatially resolved imaging of individual bonds, we carry out electron energy-loss spectroscopy in a scanning transmission electron microscopy instrument on atomically precise, thiolate-coated gold nanoclusters linked with 5,5′-bis(mercaptomethyl)-2,2′-bipyridine dithiol ligands. The images allow the identification of bridging disulfide bonds (R–S–S–R) between clusters, and X-ray photoelectron spectra support the finding. peerReviewed
Oktakarboksyftalocyjaniny jako katalizatory utleniania związków siarki
2007
Zbadano aktywność katalityczną oktakarboksyftalocyjaniny kobaltu (CoPcOC), żelaza (FePcOC) i miedzi (CuPcOC) w aerobowym utlenianiu 2-tioetanolu, siarczku sodu i L-cysteiny. Kompleksy kobaltu i żelaza okazały się efektywnymi katalizatorami homofazowymi tych reakcji. Na aktywność katalityczną wpływ mają takie czynniki, jak rodzaj skompleksowanego metalu, pH, asocjacja ftalocyjanin w roztworze.
Titanocene Selenide Sulfides Revisited: Formation, Stabilities, and NMR Spectroscopic Properties
2019
[TiCp2S5] (phase A), [TiCp2Se5] (phase F), and five solid solutions of mixed titanocene selenide sulfides [TiCp2SexS5−x] (Cp = C5H5−) with the initial Se:S ranging from 1:4 to 4:1 (phases B–E) were prepared by reduction of elemental sulfur or selenium or their mixtures by lithium triethylhydridoborate in thf followed by the treatment with titanocene dichloride [TiCp2Cl2]. Their 77Se and 13C NMR spectra were recorded from the CS2 solution. The definite assignment of the 77Se NMR spectra was based on the PBE0/def2-TZVPP calculations of the 77Se chemical shifts and is supported by 13C NMR spectra of the samples. The following complexes in varying ratios were identified in the CS2 solutions of …
Structural distortions in homoleptic (RE)4A (E = O, S, Se; A = C, Si, Ge, Sn): Implications for the CVD of tin sulfides
2001
The structures of Sn(SBut)4 and Sn(SCy)4 have been determined and adopt S4 and D2 conformations respectively; the anion [(PhS)Sn3]−, as its Ph4P+ salt, has a structure approaching Cs symmetry. In all three compounds, there are large variations in the ∠S–Sn–S within the same molecule, which have been rationalised in terms of the C–S–Sn–S–C conformations. For Sn(SR)4, the ∠S–Sn–S increases as the conformations change from trans, trans to trans, gauche and gauche, gauche, as the number of eclipsed lone pairs decreases and this rationale is shown to be applicable to a variety of A(ER)4 (A = C, Si, Ge, Sn; E = O, S, Se) and related [Mo(SR)4, Ga(SR)4−] systems. AM1 calculations have been used to …
Deposition of tin sulfide thin films from tin(iv) thiolate precursors
2001
AACVD (aerosol-assisted chemical vapour deposition) using (PhS)(4)Sn as precursor leads to the deposition of Sn3O4 in the absence of H2S and tin sulfides when H2S is used as co-reactant. At 450 degreesC the film deposited consists of mainly SnS2 while at 500 degreesC SnS is the dominant component. The mechanism of decomposition of (PhS)(4)Sn is discussed and the structure of the precursor presented.
Papillomavirus assembly requires trimerization of the major capsid protein by disulfides between two highly conserved cysteines.
1998
ABSTRACT We have used viruslike particles (VLPs) of human papillomaviruses to study the structure and assembly of the viral capsid. We demonstrate that mutation of either of two highly conserved cysteines of the major capsid protein L1 to serine completely prevents the assembly of VLPs but not of capsomers, whereas mutation of all other cysteines leaves VLP assembly unaffected. These two cysteines form intercapsomeric disulfides yielding an L1 trimer. Trimerization comprises about half of the L1 molecules in VLPs but all L1 molecules in complete virions. We suggest that trimerization of L1 is indispensable for the stabilization of intercapsomeric contacts in papillomavirus capsids.