Conversion to the third harmonic of the iodine photodissociation laser PERUN

The frequency tripling of the iodine laser PERUN is described. The maximum conversion efficiency to the third harmonic is 50%, which represents about 20 J of the 3 laser beam.     

Poisoning Effect of Acid Soluble Oil on Triflic Acid-Catalyzed Isobutane Alkylation

The rate of the isobutane alkylation reaction with secondary butenes catalyzed by trifluoromethanesulfonic acid at –20°C is experimentally found to depend on the concentration of acid soluble oil (ASO), which poisons TfOH. With an increase in the ASO molar fraction from 0.13 to 0.16, the reaction rate decreases by a factor of ten. The Hammett acidity function was determined for TfOH solutions at 25°C in the concentration range from 0 to 0.2 ASO molar fractions. The results obtained suggest that the alkylation reaction rate is proportional to the proton activity in the acid phase determined by the Hammett acidity function.     

Specific Features of the Catalytic Hydrogenation of the Norbornadiene-Based Carbocyclic Compounds

Russian Journal of Coordination Chemistry - The gas- and liquid-phase hydrogenation of bicyclo[2.2.1]hepta-2,5-diene (norbornadiene) in the presence of the Pd/γ-Al2O3 (PK-25) industrial...     

Tricarbonylchromium complexes with phenalene. Synthesis, structure, and thermal rearrangements

The reaction of phenalene with Cr(CO)₃Py₃/BF₃·OEt₂ afforded a mixture of two isomeric complexes, tricarbonyl(6a,7-9,9a,9b-·⁶-phenalene)chromium (1) and tricarbonyl(3a,6a,9b,4-6-·⁶-phenalene)chromium (2). Deprotonation of the mixture of compounds1 and2 followed by treatment with MeI, BuⁿI, or D₂O gave complexesexo-1-R-1 (3–5: R=Me (3), Buⁿ (4), or D (5)). The molecular geometry of complex3 was established by X-ray structural analysis. Heating of complex5 in toluene or C₆F₆ at 90–110 °C resulted in redistribution of deuterium among positionsexo-1,endo-1, and 3 in the resulting complexes of types1 and2 via sigmatropic shifts of the H _exo and H _endo atoms in the nonaromatic ring as well asvia inter-ring migrations of the tricarbonylchromium group. In the case of3, the methyl label is distributed among positionsexo-1 and3 to form isomeric complexes with similar structures (exo-1-Me-2 (6), 3-Me-2 (7), and 3-Me-1 (8), respectively)via processes analogous to those observed in the case of isomerization of compound5 (except for migration of the H _exo atom). The mechanisms of these rearrangements are discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1863–1880, October, 1997.     

Codimerization of norbornene and 1,3-cyclopentadiene: quantum chemical and experimental research

A comprehensive theoretical and experimental research of the diene synthesis involving norbornene (1) and 1,3-cyclopentadiene (2) was carried out. The thermodynamic and kinetic parameters were evaluated by quantum chemical methods, and the structures of stereoisomeric products and the quantitative estimation of their ratio were predicted. The results of quantum chemical analysis were experimentally confirmed. The structures of codimers of 1 with 2 and their ratio were determined by a number of physicochemical methods. A strategy combining the theoretical and experimental studies and enabling to optimize the search for objects for the synthesis and reaction conditions was proposed.     

Kinetics of cyclohexene oxidation by <Emphasis Type="Italic">p</Emphasis>-quinones in aqueous-organic solutions of cationic palladium(II) complexes

A kinetic study of cyclohexene oxidation by p-quinones in water-acetonitrile solutions of cationic Pd(II) complexes has been carried out for the first time. The observed kinetic regularities (dependence of the initial rate on the HClO₄ and p-benzoquinone concentrations) and the shape of the kinetic curves differ radically from those for the chloride systems. The unsteady-state process can be described only under the assumption that complexes of reduced palladium species with quinones are catalytically active forms. The role of solvated palladiumcarbenium ions in particular steps of the mechanism is discussed.