Die Temperaturabhängigkeit der magnetischen Suszeptibilität einiger Elementdipyridyle

The temperature dependence of the magnetic susceptibility and the EPR were investigated on 12 element dipyridyls. The magnetism of the main group compounds and of ScDipy₃ depends strongly on the temperature, owing to spin interaction of radical anions. The temperature dependence is less marked in other transition metal compounds. It is attempted to explain the dependence by means of the LCAO–MO theory.     

Die chemischen Verschiebungen von Polyvinylchlorid und dessen Modellverbindungen

Ohne Zusammenfassung     

Die chemischen Verschiebungen und die Konformationen von Iinearen Kohlenwasserstoffen. 2. Mitt

Ohne Zusammenfassung     

Die Eigenschaften einiger Chlorkohlenwasserstoffe und ihre Benutzung in der chemischen Analyse

Ohne Zusammenfassung     

Die gegenseitigen Beziehungen der physikalischen und chemischen Eigenschaften der chemischen Elemente und Verbindungen

Ohne Zusammenfassung     

Die protonchemischen Verschiebungen und die stereochemischen Strukturen von Polyvinylchlorid

Ohne Zusammenfassung     

Über die pH-Abhängigkeit der 31P- und 31C-NMR-Spektren von Cyclohexan-, Cyclohexen- und Benzenphosphonsäuren

About the pH-Dependence of ³¹P and ¹³C NMR Spectra of Cyclohexane-, Cyclohexene-, and Benzenephosphonic Acids ³¹P and ¹³C chemical shifts as well as P? C coupling constants of phosphonic acids are affected by the pH of the investigated solutions. This dependence was measured for aqueous solutions of cyclohexane-, cyclohex-1-ene-, cyclohex-2-ene-, cyclohex-3-ene-, and benzenephosphonic acid. It is shown that the ³¹P chemical shift and various ¹³C chemical shifts are well suited for the determination of pK_a values.     

Relative Basizit?t der Organotrialkoxysilane und die elektronischen Effekte der Substituenten

Ohne Zusammenfassung     

Die Tropfzeitabhängigkeit der polarographischen Halbstufen-potentiale von 2-Phenylchinoxalin

Reversible redox reactions which are followed by irreversible steps give often polarographic waves with drop life dependent shapes. A mathematical model is proposed which is capable to describe the change of the polarographic waves of quinoxalines, even at short drop lives and slow reactions of the irreversible step.     

Ueber die Spectren der chemischen Elemente und ihrer Verbindungen

Ohne Zusammenfassung     

Induktive und sterische Effekte bei der BECKMANN-CHAPMAN-Umlagerung von Alkyl-ketoxim-pikryläthern

The rates of the BECKMANN -CHAPMAN rearrangement of the ketoximpicryl-ethers 1a–1k in 1, 4-dichlorobutane are correlated with parameters describing the bulk of the substituted groups R and R′. From regression analyses it is concluded that the relative rate constants are mainly controlled by steric contributions in the ground state, such as geminal interactions of R with R′ and vicinal interactions of R′ with O? X, and less by inductive effects. Conformational equilibria between (Z)- and (E)-isomers of N-alkyl-N-picryl-amids have been studied by NMR. in several solvents.     

Protonenresonanzspektren von aromatischen N-Oxiden Berechnung der chemischen Verschiebungen,verursacht durch die Feldeffekte der N?O-gruppe

The proton NMR. spectra of a series of aromatic amines, their N-oxides and the corresponding protonated species are analysed. The results for different protons are expressed in terms of differential chemical shifts of the N-oxide with respect to the corresponding amine or to the hydrocarbon. These data are compared with calculated shielding values obtained according to the theories of McConnell & Buckingham using published data for the magnetic susceptibilities and electric dipoles of the functional groups. The major part of the shielding by the N-oxide group originates from the electric dipole. If one considers resonance structures for the aromatic N-oxides the single bond structure and the double bond structure for the N? O bond are of approximately equal importance.