Stereospecific synthesis of a key synthon for faranal — The trail pheromone of the antMonomorium pharaonis

An effective scheme is proposed for the synthesis of the methoxymethyl derivative of racemic (erythro)-5-iodo-3,4-dimethylpentan-1-ol (a for obtaining faranal) from methyl (erythro)-3,4,5-trimethylhex-5-enoate — the product of the diastereospecific 1,4-addition of 2,3,-dimethylallylmanganese chloride to methyl crotonate. Institute of Organic Chemistry, Urals Branch, Russian Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 459–463, May–June, 1993.     

Transition metal σ-complexes in organic synthesis. 4. Cross coupling of allyl esters and allyl aryl sulfones with organotitanium compounds in the presence of palladium complexes

Conclusions The reactions of organotitanium compounds PhTi(OPr-i)₃ and MeTi(OPr-i)₃ with allyl acetates, allyl phenyl ethers, allyl aryl sulfones, and allylic tosylates and mesylates are catalyzed by Pd complexes and lead to the formation of cross-coupling products.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2159–2166, September, 1988.     

Cu/ZnO and Cu/ZrO2 interactions studied by contact angle measurement with TEM

A technique of contact angle measurement was applied to the nano-scale oxide-supported metal particles. For Cu supported on ZnO and ZrO2 the angles were found to increase and the work of adhesion to decrease with increasing particle size. Such a trend is interpreted as an effect of negative contact line tension of 2.1 x 10(-9) J m(-1) and 1.0 x 10(-9) J m(-1) in the Cu/ZnO and Cu/ZrO2 system, correspondingly. For the small-sized Cu particles the apparent work of adhesion on ZnO support is higher than that on ZrO2.     

Planar thiol-sensitive sensor elements for the determination of butyrylcholinesterase activity and analysis of its inhibitors

A method for the analysis of the thiocholine concentration, as well as the activity of the butyrylcholinesterase (BChE) enzyme and its inhibitors, using thiol-sensitive planar sensors has been proposed. Thiocholine sensitivity of the sensors was achieved by a mediator layer of manganese dioxide formed on a working carbon electrode. The detection limits for BChE and its inhibitor diazinon were 1 × 10^?10 M and 1 × 10^?9 M, respectively. The approach that was developed simplifies the analysis of inhibitors. It could be used for water quality and environmental monitoring.     

X-Ray Photoelectron Spectroscopy of Stabilized Zirconia Films with Embedded Au Nanoparticles Formed under Irradiation with Gold Ions

Nanosized films of stabilized zirconia with Au nanoparticles formed by implanting Au ions are studied by X-ray photoelectron spectroscopy and transmission electron microscopy. The effect of irradiation of films with Au ions and postimplantation annealing on the distribution of chemical elements and zirconium- containing ZrO _x compounds over the depth of the films is studied. Based on the data on the dimensional shift of the Au 4 f photoelectron line, the average value of the nanoparticle size is determined.

     

Diastereoselective addition of organomanganese compounds to α-alkoxysubstituted propanals

Reactions of organomanganese compounds R¹MnI (R¹ = Ph, 4-MeC₆H₄-, Me, Bu,n-C₇H₁₅, BuC=C, PhOC), prepared from R¹Li and Mnl₂ in Et₂O, with aldehydes MeCH(OR²)CHO (R² = CH₂Ph, CH₂OMe, CH₂OCH₂Ph) affordthreo-alcohols MeCH(OR²)CH(OH)R¹ with high diastereoselectivity. The interactions of phenylmanganese derivatives PhMnX (X = Cl, Br, I), Ph₂Mn, and Ph₃MnLi with 2-benzyloxypropanal were used as examples for studying the influence of reagent and solvent nature on addition diastereoselectivity.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 178–181, January, 1993.     

Defect sites in thin films of germanium dioxide irradiated with silicon ions

Optical transmission spectra of GeO₂ films irradiated with silicon ions and subjected to postimplantation annealing in the regime of silicon nanocrystal formation are analyzed. It is shown that point defects form in the films after irradiation with doses D ～ 10²⁰ m^?2: germanium electron centers, neutral oxygen vacancies, and Ge²⁺ centers, which have been annealed at a temperature of 1000°C for an hour. At D ≥ 1 × 10²¹ m^?2, more complex defects arise in the films, which are only partially annealed under the same conditions.