In situ generated hypoiodous acid in an efficient and heterogeneous catalytic system for the homo-oxidative coupling of thiols

Supported hydrogen peroxide on polyvinylpolypyrrolidone (PVPH2O2), silica sulfuric acid (SiO2-OSO3H) and catalytic amounts of potassium iodide (KI) has been developed as a heterogeneous medium for the rapid oxidative coupling of thiols into symmetrical homodisulfides. This oxidizing system proceeds under extremely mild conditions and gives no other oxidized side products

Co-Adsorption of Mixed Cationic/Non-Ionic Surfactants on a Quartz Surface

The co-adsorption of binary mixtures of tetradecyltrimethylammonium bromide (TTAB) and nonyl phenyl ethoxylates (NP-n series) from their aqueous solutions on to quartz has been studied. None of the ethoxylates adsorbed on to the quartz when alone, but considerable adsorption took place from the mixture with cationic TTAB. The adsorption of TTAB was increased in the presence of ethoxylates below its CMC due to chain–chain interaction between the cationic/non-ionic surfactants. FT-IR spectroscopic studies indicated that micelle-like aggregate structures formed on the quartz surface even below the CMC. Zeta potential measurements were carried out in order to understand the adsorption behaviour

Polyvinylpolypyrrolidoniume tribromide (PVP-Br3) as efficient and metal-free agent for the selective oxidation of alcohols, trimethylsilyl ethers and oximes under mild conditions

Polyvinylpolypyrrolidoniume tribromide (PVP-Br3) was found to be a metal-free and highly efficient oxidizing polymer for the selective oxidation of a variety of benzylic alcohols, deprotection and selective oxidation of trimethylsilyl ethers and oximes to the corresponding aldehydes and ketones at room temperature in moderate to high yields. The main advantages of this procedure are selective oxidation, efficient, milder reaction conditions, shorter reaction times, and easier work-up

Synthesis and characterization of Co (II) and Fe (III) Schiff base complexes grafted onto mesoporous MCM-41: A heterogeneous and recyclable nanocatalysts for the selective oxidation of sulfides and oxidative coupling of thiols

<p>Novel organic–inorganic hybrid heterogeneous catalysts containing cobalt(II) and iron(III) Schiff base complexes, grafted on the internal surface of MCM-41 pores were prepared by introducing a metal salt into a mesoporous silica functionalized with a Schiff base ligand. The chemical and physical properties of the catalysts were investigated by BET, TGA, XRD, FT-IR, and TEM techniques. These complexes were found to be efficient, selective catalysts for the oxidation of various sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides with urea hydrogen peroxide in excellent yield at room temperature. The designed catalytic system prevents effectively the overoxidation of sulfides and thiols to sulfoxides and sulfones, respectively. Also the heterogeneous catalysts can be recovered easily and reused many times without significant loss of activity and selectivity.</p

Bis[N-(3-aminopropyl)propane-1,3-diamine-&amp;#954;3N,N&amp;#8242;,N&amp;#8242;&amp;#8242;]cadmium nitrate perchlorate

The title complex, [Cd(C6H17N3)2](ClO4)(NO3), was synthesized by the reaction of Cd(NO3)2&amp;#183;4H2O, bis(3-aminopropyl)amine and sodium perchlorate in methanol. The asymmetric unit of the title complex consists of one Cd2+ cation, two tridentate bis(3-aminopropyl)amine ligands, one nitrate anion and one perchlorate anion. The Cd2+ cation is coordinated by six N atoms of the bis(3-aminopropyl)amine ligands in a slightly distorted octahedral coordination geometry. In the crystal, molecules are held together by an intricate network of N&amp;#8212;H...O interactions. One of the two amine ligands was found to be disordered over two sets of sites, with a ratio of 0.802&amp;#8197;(3):0.198&amp;#8197;(3), similarly to the nitrate anion, with a ratio of 0.762&amp;#8197;(10):0.238&amp;#8197;(10)

Nickel Schiff base complex anchored on Fe₃O₄@MCM-41 as a novel and reusable magnetic nanocatalyst and its application in the oxidation of sulfides and oxidative coupling of thiols using H₂O₂

<p></p> <p>A novel and reusable nanocatalyst was synthesized by anchoring a nickel Schiff base complex onto Fe₃O₄@MCM-41 (Fe₃O₄@MCM-41@Ni-P2C) and characterization was accomplished with Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic absorption spectroscopy (AAS) techniques. This catalytic system was efficiently used for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to corresponding disulfides using H₂O₂ as green oxidant at room temperature. These reactions were carried out in a green solvent (ethanol) and/or under solvent-free conditions with short reaction time, complete selectivity and very high conversion under mild reaction conditions. More importantly, separation and recycling of this magnetic catalyst can be easily done through a simple and low cost magnetic separation process.</p