Elektronenstossinduzierte Fragmentierung von Acetylenverbindungen. IX—Struktur der Stabilen [C9H11]+-Ionen aus Isomeren C9H11-Chloriden

The structure of stable [C₉H₁₁]⁺ ions from different model compounds with the molecular formula C₉H₁₁Cl has been estimated by energy measurements. It has further been shown that acetylenic compounds cyclise to form aromatic ions in the range of the appearance potentials.     

Invariant Manifolds in Dissipative Dynamical Systems

Invariant manifolds like tori, spheres and cylinders play an important part in dynamical systems. In engineering, tori correspond with the important phenomenon of multi-frequency oscillations. Normal hyperbolicity guarantees the robustness of these manifolds but in many applications weaker forms of hyperbolicity present more realistic cases and interesting phenomena. We will review the theory and present a number of examples using normalization-averaging techniques.Dedicated to nonlinear scientist Ale Tondl on his 80th birthdayMathematics Subject Classifications (2000) 34C30, 34C20.     

Thiamorphinans. I

The present paper deals with the synthesis of 5,5a,6,7,8,9-hexahydro-5,9a-iminoethano-4H-naphtho[2,1-b] -thiophenes (I) as derivatives of the first of three novel isomeric S-heterocycles with morphinan-like structure (“thiamorphinans”).     

Étude de quelques dérivés de la pyrazoline-2: Spectres infrarouge et methode CNDO/2

The infrared spectra of some derivatives of 2-pyrazoline have been studied in the region of the CN and N-H stretching bands.The N-H stretching frequency seems to be related to Taft's σ^* constants of the substituents bound to the intracyclic carbon atoms. The “acidity” of this group seems to be considerably less than in pyrrole or in carboxylic amides.Absorption spectra of the pure compounds or of moderately concentrated solutions suggest the existence of intermolecular hydrogen bonding.The hybridization state of nitrogen atom (1) seems to be approximatively sp³, without any noticeable conjugation with the CN(2) double bond. In those cases where two conformers could be assumed to exist only one has been observed.These results are in accordance with those of a molecular orbital calculation by the CNDO/2 method. This calculation suggests that in 5-methyl-2-pyrazoline, the hydrogen atom bound to N(1) is trans with respect to the methyl group.