Characterization of iron(III) oxide films used for photoelectrode by means of cems

Thin iron oxides deposited on semi-conductive glass by a spray pyrolysis technique were analysed by Conversion Electron Mössbauer Spectrometry (CEMS). Iron oxide deposited on SnO₂ coated glass was composed of a large grained particles of crystalline α?Fe₂O₃, which showed sextet. The doublet and sextet appeared in CEM spectra of iron oxides deposited on In₂O₃ and WO₃ coated glasses. The sextet was due to α?Fe₂O₃ and the doublet was attributted to the superparamagnetic microcrystalline α?Fe₂O₃ (≈15nm) rather than to spinel compounds of iron. The iron oxide deposited on ZnO coated glass gave a doublet in CEM spectra. It was supporsed to be due to very fine particle of α?Fe₂O₃ (<100nm). It was found that iron oxide films obtained by spray pyrolysis were dependent on the kinds and the temperature of the semi-conductive materials coated on glass.     

Impedance and frequency characteristics of electrode-separated piezoelectric quartz crystals in liquids

The electrical equivalent circuit parameters of an electrode-separated piezoelectric quartz crystal (PQC), where the gaps between the electrodes and the crystal plate were filled with various liquids, were evaluated from admittance measurements and were compared with those of a normal PQC with Au electrodes adhering to the crystal plate. The resistance parameter in the equivalent circuit of the electrode-separated PQC was more sensitive to the specific conductivity, density and viscosity of liquids than was that of the normal PQC. This parameter, unlike that of the normal PQC, was also affecteded by the permittivity of the liquid. The effect of the liquid properties on the other parameters in the equivalent circuit and the series resonant frequency are also discussed.     

1,3-bis(phenylsulfonyl)butadienes: synthesis applying knoevenagel-type condensation and michael-type addition-cyclization with enamines

Knoevenagel-type condensation of 1,3-bis(phenylsulfonyl)propene with aldehydes provided electron-deficient dienes, 1,3-bis(phenylsulfonyl)butadiene derivatives, and one of these dienes, 4-[3,4-(methylenedioxy)]phenyl derivative was applied to Michael-type addition with enamines to form six-membered ring systems.     

Revised structure of diastereomeric 3,8-di-t-butylspiro[4,4]nonane-1,6-diones

The recently assigned diastereomeric configuration of 3,8-di-t-butylspiro[4.4]nonane-1,6-dione has been revised based on the X-ray analysis.     

Determination of iron(III) and aluminum in solution with a piezoelectric quartz crystal coated with silicone oil

The frequency of the crystal connected to an integrated circuit oscillator changed on absorption of iron(III) or aluminum ar pH 3.8–5.8 and 5.0–6.0, respectively. Absorption of iron(III) at pH ≥ 5.0 was prevented by addition of excess of sulfate. Iron(III) was determined at pH 4.7; 5–100 μM solutions of both species may be determined with a r.s.d, of ≤3%.     

An organoantimony catalyst for peptide synthesis; preparation and aminolysis of triphenylantimony bis(aminoacylate)s

Triphenylantimony bis(aminoacylate)s [Ph₃Sb(O A)₂, A = Z Gly, Z Phe, Z Leu, Bz Phe] were prepared by direct condensation between triphenylstibine oxide and N-protected amino-acids in acetone. The aminolysis of these antimony aminoacylates by amino-acid esters gave corresponding dipeptides, which lead to a catalytic dipeptide synthesis using triphenylstibine oxide as a catalytic precursor of the antimony aminoacylate in situ.     

Solvent-controlled addition of alkynyltins or allylic tins to aldehydes catalyzed by indium trichloride

Indium trichloride promoted catalytically the addition of alkynyltins or allylic tins to aldehydes in two ways: transmetallation with the tin compounds and activation of aldehydes as a Lewis acid. The stcreochcmical outcome in the addition of cinnamyltributyltin to an aldehyde strongly indicates that control of the process can be achieved simply by the choice of solvent acctonitrile or dichloromethane.     

Effect of supports on copper Catalysts for Methanol Synthesis from CO2 + H2

Methanol was synthesized from carbon dioxide and hydrogen over various supported copper catalysts. A support was selected from the viewpoint of its acid-base properties. Acid supports showed high selectivity but low activity. Neutral and basic supports produced only carbon monoxide. Amphoteric supports showed high activities. Among them, TiO₂ supports suppressed the reverse water gas shift reaction (CO formation). The role of supports was discussed on the basis of in situ infrared results.