Amination of aryl- and vinylacetylenic compounds catalyzed by rhodium(I) complexes

New rhodium-catalyzed amination reactions of arylacetylenes and cyclohexen-1-ylacetylene in the presence of strong bases with the use of carbon dioxide as an auxiliary are described. Secondary amines attack the terminal carbon atom of the triple bond followed by protonation of the adjacent carbon atom. Alternatively, the reaction can proceed further with the addition of the second alkyne molecule. The conditions for the selective synthesis of enamines (up to 87% yield) or α-substituted propynylamines (up to 86% yield) are reported. Dipartimento di Chimica Organica e Industriale dell'Università, Viale delle Scienze, I-43100 Parma, Italia. Dipartimento di Chimica, Università della Calabria, Arcavacata di Rende, I-80036 Cosenza, Italia. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 966–970, May, 1998.     

Una proprietà gruppale delle involuzioni planari che mutano in sé un'ovale di un piano proiettivo finito

Summary The purpose of the present paper is to prove the following theorem: Let Ω be an oval in the projective plane P of odd order n. If P admits a collineation group G wich maps Ω onto itself and is doubly transitive on Ω, then P is desarguesian, Ω is a conic and G contains all collineations in the little projective group PSL(2, n) of P wich leaves Ω invariant.

---

---

Entrata in Redazione il 5 april 1977.     

Laserspectroscopic studies of collective properties of neutron deficient Ba Nuclei

Isotope shifts and hyperfine structure of the BaI resonance-line (λ=553.6 nm) have been measured by dye laser induced resonance fluorescence on an atomic beam for^{135m, 129g, 129m, 126}Ba thus extending previous high resolution measurements of neutron deficient Ba nuclides (N<82). The experimental results, now available for 16Ba isotopes and isomers withA=140?126, are used to deduce differences of rms charge radii, magnetic dipole and electric quadrupole moments. While the groundstates display a pronounced odd-even staggering the h 11/2^? isomers^135mBa and^133mBa show a decreased staggering. Conspicuously the isomer shift of theg 7/2⁺ isomer^129m Ba proves to be negative. The nuclear structure information is discussed in the context of gammaspectroscopic studies of transitional nuclei with 50<N,Z<82 and on the basis of a quasi-particle-plus-triaxial rotor model. The isotope shift discrepancy observed is fairly well described by the droplet model.     

The level scheme of 135Pr: Prolate deformation of the 112− isomer

The level scheme of ¹³⁵Pr has been investigated by means of off-beam γ-ray and conversion electron measurements as well as by methods of in-beam γ-spectroscopy. We measured γ-ray and conversion electron singles spectra, off-beam and in-beam γγ coincidences and γ-angular distributions. From the experimental data a detailed scheme of 22 excited levels for ¹³⁵Pr has been constructed. In addition to members of the decoupled band based on the $\text{11}\text{2}{}^{\mathrm{?}}$ state six further negative parity states were identified. These states are strongly populated in the β-decay of a $\text{9}\text{2}$ isomer in the parent nucleus ¹³⁵Nd. A comparison of all the negative parity states with predictions of the alignment coupling model showed a nearly quantitative agreement, if softness of the core is taken into account. In this case, a prolate deformation with a deformation parameter β ≈ 0.13 was obtained for the $\text{11}\text{2}{}^{\mathrm{?}}$ isomer in ¹³⁵Pr.     

Bis(triazacyclohexane) sandwich complexes of (Cu(I))(2), Cu(II) and Zn(II): complexes with cuprophilic attraction between two cationic copper(I) leading to unusual reactivity with dioxygen

As the first 1st-row transition metal complexes having six tertiary amine donor groups, bis(triazacyclohexane) sandwich complexes [L2M](BF4)2 (L = benzyl- or p-fluorobenzyl-triazacyclohexane, M = Cu or Zn) have been obtained by the protonolysis of Et2Zn in the presence of L or by reaction of [Cu(MeCN)4](BF4) with L in CH2Cl2 and subsequent air oxidation via an unprecedented Cu(I)(2) sandwich complex containing a short Cu-Cu contact.     

The interfacial energy of two-dimensional bidisperse cellular fluids

The mixing energy of two biphasic fluid systems (dispersions of two liquids or a liquid and a gas, A and B in a liquid C), confined between two parallel plates, is calculated. Our attention is limited to concentrated and monodisperse systems, i.e. emulsions and foam/emulsions consisting of equal-size (if of the same composition) cells separated by a thin liquid film. It is demonstrated that the multiphase mixtures ordered into regular patterns can be stable in a wide range of interfacial tensions acting along A-C and B-C interfaces and also in a wide range of volume fractions of fluid A. Anisotropic properties of such well-ordered structures are also demonstrated.Received: 8 December 2003, Published online: 4 May 2004PACS: 83.80.Iz Emulsions and foams - 05.65. + b Self-organized systems     

SIMS Analysis of Uranium and Actinides in Microparticles of Different Origin

In the framework of the projects Environmental Sampling and High Performance Trace Analysis in support to the International Atomic Energy Agency (IAEA) and the Euratom Safeguards Office (ESO), the research has been focused on the identification and characterisation of particles of interest containing mainly U and other actinides.Multiple analyses, elemental and isotopic, of single radioactive particles in the µm-size range are key-tools in environmental research and in nuclear forensics. The main purpose in the analysis of single particles by SIMS is the determination of their isotopic composition that has been demonstrated successfully for uranium and plutonium particles. From these results, the enrichment of the material produced, the process used for the enrichment as well as the starting material employed (natural or reprocessed uranium) can be identified.