ansa-Metallocene Derivatives : IV. Synthesis and molecular structures of chiral ansa-titanocene derivatives with bridged tetrahydroindenyl ligands

A synthesis for racemic ethylene-bis(4,5,6,7-tetrahydro-1-indenyl)titanium dichloride is described. The molecular structures of this compound, of its meso- isomer and of a binaphtholate complex of the (S,S)-enantiomer have been determined. Cleavage of this binaphtholate complex gives the pure (S,tS)-enentiomer.     

Elektronenstossinduzierte Fragmentierung von Acetylenverbindungen—VIII:. Struktur der stabilen und instabilen Ionen [C9H9]+ aus isomeren C9H10-Kohlenwasserstoffen

The appearance potentials of [C₉H₉]⁺ have been estimated and the enthalpy of formation, calculated from the data, is correlated with different structural proposals. Open chain structures can be eliminated in favour of aromatic ones (vinyltropylium or indanyl cation). The structure of the unstable [C₉H₉]⁺ ions is investigated by means of ¹³C-labelled compounds. The results are also in agreement with the acceptance of aromatic structures.     

Durch wasserstoff-transfer induzierte radikal-eliminierungen aus ortho-substituierten benzoesäuremethylestern

The investigation of some ²H-labelled compounds as well as the analysis of energetic properties (appearance potential measurement, kinetic energy release) reveal some unusual elimination of radicals (CH₃^., OH^. resp. CHO^.) from ortho substituted bencoic acid methyl esters. It can be shown that most of the reactions are induced by a novel hydrogen transfer to the carboxyl function.     

Massenspektrometrische Untersuchung von Amiden. VI—Mechanismus der Methyl-Abspaltung aus Crotonsä;urepiperidid

By the investigation of ²H labelled compounds, it has been established that in the case of crotonoyl piperidyl only the hydrogens of the methyl group participate in the elimination of CH₃·.     

Ungewöhnliche Methyl-Abspaltungen aus Nicht Endständigen Kohlenstoffpositionen Bei p-Methylstyrol

The mechanism of methyl elimination has been investigated with the help of ¹³C-labelled p-methylstyrene. Not only terminal C atoms participate in this process; however, neither complete nor partial C scrambling ensues prior to the fragmentation.     

Energetische Betrachtungen zur Intramolekularen Solvatisierung von Ionen bei der Elektronenstoss-Induzierten Fragmentierung von α,ω-Bis-(Trimethylsilyl)-Äthern

By means of AP measurements it has been shown that the stable [M? CH3]+ ions from α,ω-bis(trimethylsilyl) ethers of the type TMS? o? (CH₂)_n? O? TMS (n = 2 to 7) do not possess a cyclic structure.     

Synthesis, crystal structure and antiradical effect of copper(II) Schiff base complexes containing five-, six- and unusual seven-membered rings

The synthesis and solid-state structure of mononuclear copper(II) complexes [Cu(SAIB)(H(2)O)(2)] (1), [Cu(SBAIB)(H(2)O)(2)]·H(2)O (2) and [Cu(SGABA)(H(2)O)(2)] (3) are described. Schiff base ligands H(2)SAIB, H(2)SBAIB and H(2)SGABA chelate the copper(II) ion in an O,N,O tridentate fashion. The square-pyramidal geometry of the final complexes is completed by two water ligands. The formation of an unusual seven-membered ring in the set of copper(II) N-salicylidene-aminoacidates is reported. Compounds 1-3 were evaluated by the antiradical activity assay.