Direct oxidation of methane to oxygenates over heteropolyanions

Partial oxidation of methane to formaldehyde and methanol was studied at atmospheric pressure in the temperature range of 700-750 °C using heteropolycompound catalysts （NH4）6HSiMo11FeO40, （NH4）4PMo11FeO39, and H4PMo11VO40, which were prepared and characterized by various analysis techniques such as infrared, visible UV, XRD and DTA. O2 or N2O was used as the oxidizing agent, and the principal products of the reaction were CH3OH, CH2O, CO, CO2, and water. The conversion and the selectivity of products depend strongly on the reaction temperature, the nature of oxidizing agent, and the composition of catalyst.     

Effect of temperature and silicon resistivity on the elaboration of silicon nanowires by electroless etching

The morphology of silicon nanowire (SiNW) layers formed by Ag-assisted electroless etching in HF/H₂O₂ solution was studied. Prior to the etching, the Ag nanoparticles were deposited on p-type Si(1 0 0) wafers by electroless metal deposition (EMD) in HF/AgNO₃ solution at room temperature. The effect of etching temperature and silicon resistivity on the formation process of nanowires was studied. The secondary ion mass spectra (SIMS) technique is used to study the penetration of silver in the etched layers. The morphology of etched layers was investigated by scanning electron microscope (SEM).     

Novel electron-deficient oligo(phenyleneethynylene) derivatives for molecular electronics

This work reports synthesis and characterizations of two new electron-poor “oligo(phenyleneethynylene) (OPE) type” molecular wires for fundamental studies of electron transport in molecular junctions. These OPE derivatives display three aromatic rings functionalized (i) with NO₂ (OPN) or fluorine (OPF) groups on the central aryl core and (ii) with the requisite protected thiolate anchoring groups on the lateral rings at both ends. We show that the moderately effective Sonogashira couplings can give access to such rare electrodeficient molecules but are unfortunately associated with significant side reactions. We detail the choice of adequate reaction conditions to allow the recovery of suitable amounts of compounds bearing several strongly electron-withdrawing substituents on their central ring for further study of the physical properties.