The dielectric loss of very diluted solutions of four aromatic and three aliphatic amines in three non polar aliphatic solvents at 20 °C has been measured. The wave numbers cover 0.1 to 200 cm
Novel magnesium(II) porphyrazine with peripheral methyl(3,5-dibromophenylmethyl)amine groups was synthesized in a multi-step procedure starting from commercially available diaminomaleonitrile. All intermediates and the final macrocycle were characterized using UV–Vis, FT-IR, MS and various NMR techniques. The absorption and emission properties of the macrocycle were evaluated in N,N-dimethylformamide, dimethyl sulfoxide, and dichloromethane. The potential photosensitizing activity was evaluated by assessing the ability of the macrocycle to generate singlet oxygen in dimethyl sulfoxide and N,N-dimethylformamide.
Supplementary to a preceding investigation on primary amines, the dielectric loss increments of three aromatic dimethylamino compounds, diphenylamine, N-methyldiphenylamine and triphenylamine, and of dicyclohexylamine have been measured in very diluted solutions at 20 °C. The loss data resulting from 0.1 up to 250 cm -1 are now covering the complete absorption region due to reorientation of the permanent molecular dipole, especially that part based on inversion. To resolve this part, the absorption curves are analysed in terms of three areas using the same method as done for primary amines. By this the dipole components assigned to the special reorientation processes may be discerned and discussed. So the dipole component of the dimethylamino group which reorientates by intramolecular motion is smaller than that of the amino group. The occurrence of an inversion process is demonstrated, but the molecular dipole component governing it also may reorient more slowly as the result of a hindered inversion. The additional reorientation of a mesomeric moment by twisting of the phenyl groups is suggested in triphenylamine and in the diphenyl compounds. The aliphatic dicyclohexylamine only shows a Poley absorption area, increased perhaps by intramolecular libration. Orientierung der innerhalb des Moleküls beweglichen Momentkomponente gehört, aber bei Wellenzahlen liegt, die um eine Dekade kleiner sind. Es wird daher solchen polaren Molekülen in der gemessenen Probe zugeschrieben, bei denen die Inversion kurzzeitig behindert ist. Das Absorptionsgebiet der molekülfesten Momentkomponente liegt bei noch längeren Wellen.
In einer vorangehendenFrüher wurden parallel zu Anilin meist auch Diphenylamin und Triphenylamin [4-11] untersucht. Dabei erhielt man allgemein wichtige Hinweise für ein molekülinternes Umklappen des Dipolmoments von Aminen, denn bei ihnen fand man ebenfalls, daß sich eine Momentkomponente sehr schnell umorientiert. Ihre Größe und die zugehörige Zeitkonstante waren aber bisher nur durch Extrapolation zu ermitteln. Es bietet sich daher an, auch bei diesen und anderen sekundären und tertiären Aminen die Absorption von Submillimeterwellen zu messen, um die Kenntnisse über alle Orientierungsvorgänge ihrer permanenten Dipole und deren charakteristische Parameter zu vervollständigen.
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