Protein recognition by a self-assembled deep cavitand monolayer on a gold substrate

This paper details the first use of a self-folding deep cavitand on a gold surface. A sulfide-footed deep, self-folding cavitand has been synthesized, and its attachment to a cleaned gold surface studied by electrochemical and SPR methods. Complete monolayer formation is possible if the cavitand folding is templated by noncovalent binding of choline or by addition of space-filling thiols to cover any gaps in the cavitand adsorption layer. The cavitand is capable of binding trimethylammonium-tagged guests from an aqueous medium and can be deposited in 2 × 2 microarrays on the surface for characterization by SPR imaging techniques. When biotin-labeled guests are used, the cavitand:guest construct can recognize and immobilize streptavidin proteins from aqueous solution, acting as an effective supramolecular biosensor for monitoring protein recognition.     

Synthesis of wide band gap nanocrystalline NiO powder via a sonochemical method

A sonochemistry-based synthesis method was used to produce nanocrystalline nickel oxide powder with ∼20 nm average crystallite diameter from Ni(OH)₂ precursor. Ultrasound waves were applied to the primary solution to intensify the Ni(OH)₂ precipitation. Dried precipitates were calcined at 320 °C to form nanocrystalline NiO particles. The morphology of the produced powder was characterized by transmission electron microscopy. Using sonochemical waves resulted in lowering of the size of the nickel oxide crystallites. FT-IR spectroscopy and X-ray diffraction revealed high purity well-crystallized structure of the synthesized powder. Photoluminescence spectroscopy confirmed production of a wide band-gap structure.     

Ruthenium/dendrimer complex immobilized on silica-functionalized magnetite nanoparticles catalyzed oxidation of stilbenes to benzil derivatives at room temperature

A new ruthenium/dendrimer complex stabilized on the surface of silica-functionalized nano-magnetite was fabricated and well characterized. The nano-catalyst showed good activity in the synthesis of benzil derivatives via the oxidation of stilbenes with high turnover frequency (TOF) at room temperature. Moreover, the catalyst could also be reused up to fifteen times without any loss of its activity.     

Effect of high electric field on the dc conduction of TeO2-V2O5-MoO3 amorphous bulk material

Effect of high electric field on the dc conductivity of TeO₂-V₂O₅-MoO₃ amorphous bulk samples with different molar ratio of each component was investigated with gap-type electrode arrangement. At low electric fields, the current-voltage (I–V) characteristics has a linear shape, while at high electric fields (>10³ V/cm), bulk samples show nonlinear behavior (nonohmic conduction) and current-voltage characteristics shows increasing deviation from Ohm’s law with increasing current density. High-field effect of Pool-Frenkel type was observed at electrical fields about 10³−10⁴ V/cm. In addition, positive deviation from Pool-Frenkel effect was observed when a field higher than about 10⁴ V/cm was applied.     

Clay Supported Bis-(trimethylsilyl)-chromate: An Efficient Reagent for Oxidative Deoximation

 A convenient method for the direct conversion of oximes to carbonyl compounds upon treatment with clay supported BTSC under classical heating as well as microwave irradiation in a solvent-free system is described.     

Zeofen: A User-Friendly Catalyst for Oxidative Cleavage of Tetrahydropyranyl Ethers Under Non-Aqueous Conditions

Summary.  Primary and secondary tetrahydropyranyl ethers are efficiently converted to carbonyl compounds in excellent yields by zeofen under non-aqueous conditions. Received November 21, 2000. Accepted (revised) January 9, 2001     

Preparation of Silica Supported Tin Chloride: As a Recyclable Catalyst for the Silylation of Hydroxyl Groups with HMDS

Silica‐supported tin chloride [SiO₂‐Sn(Cl)_4‐n] has been prepared by mixing tin chloride with activated silica gel in toluene under refluxing conditions for one day. A range of primary, secondary, and tertiary alcohols as well as phenolic hydroxyl groups were converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane in the presence of catalytic amounts of silica‐supported tin chloride at room temperature. An excellent chemoselective silylation of hydroxyl groups in the presence of other functional groups was also observed. This catalyst could be recycled and reused fifteen times without loss of efficiency.