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Treatment of electron-rich aromatic derivatives with cerium (IV) ammonium nitrate coated on silica (CAN/Si02) affords nitro aromatic compounds. The scope and the limitation of this reaction are discussed.

The metastable hexagonal form of MoO 3 has been successfully prepared starting from the ammonium molybdate, using a “Chimie Douce” reaction with NO 2 gas. The lattice parameters of the as-prepared material were determined by XRD analysis to be: a = 10.633(2) A and c = 3.719(1) A. The composition of this material obtained by physical and chemical analysis is MoO 3 , 0.09 H 2 O, showing that a small amount of water molecules remained while there were no more ammonium ions in this structure. The structural transformation from hexagonal to stable orthorhombic α-MoO 3 phase was observed at 350°C. It was also shown that NO 2 reaction is a very useful method to remove topotactically ammonium ions from a parent structure at low temperature. This “Chimie Douce” process appears to be very promising for obtaining new metastable oxides with large tunnels or interlayer distances.

Polarization of La2CuO4 in 1 N KOH at 900 mV (66 h) yields a metallic material which exhibits a superconducting transition around 47 K. The room temp. resistivity of this material is strongly decreased which is explained by the mixed valency of Cu resulting from the electrochemical treatment.