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The emergence of a graded primary school system posited the group and not the individual as the focus of the work in schools. However, the ideal of homogeneous school classes revealed, the gap between the abstract model of the division of schools into classes and the difficulty of managing the heterogeneity of schoolchildren. The belief in a rational organization of schooling embodied in class teaching and the context of an intended expansion of school attendance promoted the development of graded schools with many classes. Yet the new system did not always work as intended. This, however, led to reforms rather than to the rejection of the new model of graded schools. The analy- sis of the school policies of the city of Lisbon and the active engagement of local school councils shows that different attempts to reorganize school classes and to streamline the advancement of the pupils in order to guarantee the homogeneity of school classes met with only little success. It was only in this context that the question of age for grouping chil- dren in school classes may have gained traction.

Madrider Mitteilungen, Vol. 26 (1985), Deutsche Zusammenfassung folgt.

This paper investigates in the framework of maritime surveillance applications, i.e. oil spill and ship detection, the use of the satellite duo, TerraSAR-X (TS-X) and TanDEM-X (TD-X), to acquire almost simultaneously pairs of independent SAR measurements using the standard single receive antenna mode (SRA) and the experimental dual receive antenna mode (DRA). With the DRA mode switched-on along track interferometry (ATI) as well as fully polarimetric SAR (polSAR) can be accessed [1]. On the other hand, SRA mode allows acquiring only a subset of polarization channels, i.e. dual-pol, beside the ordinary single polarization. The importance of polSAR and dual-pol data is nowadays well established in many Earth Observation applications, including maritime surveillance. However the major drawbacks that limit the use of polSAR and dual-pol SAR data in applications like oil and ship detections are the reduced swath width and azimuth resolution. Exploiting the TanDEM-X pursuit monostatic configuration during the science phase [2], it has been possible for the first time to directly compare simultaneous SAR measurements of marine slicks and targets using both single and multi-polarization data. The comparison takes into account system parameters like, signal to noise ratio (SNR) and target to clutter ratio (TCR).

Seit der Entdeckung von Triazenido- und Pentaazadienidoliganden sind viele Beispiele von Komplexen mit diesen mehrzähnigen Linganden synthetisiert und charakterisiert worden. Untersuchungen haben gezeigt, dass diese Liganden unterschiedliche Koordinationsmöglichkeiten aufweisen. Sie können sowohl einzähnig, verbrückend oder chelatisierend koordinieren. Die vorliegende Arbeit ist in zwei Abschnitte unterteilt. Im ersten Teil werden die Ergebnisse von Umsetzungen beschrieben, welche zur Darstellung von Triazenidokomplexen führte. Die gebräuchlichsten Synthesewege für Triazenidokomplexe, die auch in dieser Arbeit angewendet wurden, sind die Umsetzungen von Triazenen mit Metallhalogeniden in Anwesenheit einer Base, sowie die Umsetzungen von Metalltriazeniden mit Metallhalogeniden oder Salzen mit voluminösen Kationen. Dabei wurden folgende Komplexe erhalten: [Na2(tolyl-N3-tolyl)2(THF)3]n, [RuCl(ClC6H4N3C6H4Cl)(p-Cymol)], [Ru(tolyl-N3-tolyl)3], [RuCl(tolyl-N3-tolyl)(Ph2PCH2C4H7O2)2], [PPh4]2[Ag4Cl4(ClC6H4N3C6H4Cl)2], [(Ph3P)Rh(tolyl-N3-tolyl)2Cl] und [Et4N]2[Ag2(ClC6H4N3C6H4Cl)4]. Des Weiteren wurde versucht, Iodoniumtriazenidokomplexe über die Umsetzung von Silbertriazenid mit Iod herzustellen. Dies führte über die Oxidation des Triazenids zur Bildung der Diazoniumverbindung, ClC6H4N=NC6H4Cl. Der zweite Teil dieser Arbeit beschäftigt sich mit Pentaazadienidokomplexen. Es wurden die Komplexe [RuCl(tolyl-N5-tolyl)(C6H6)], [Et4N][Ag2(tolyl-N5-tolyl)3], [PPh4][Ag2(tolyl-N5-tolyl)3], [(n-Bu)4N][Ag2(tolyl-N5-tolyl)3] und [(n-Bu)4N]3[Ag3I6] erhalten. Letztlich wurden analog den Umsetzungen von Triazenidoverbindungen mit Iod, zur Darstellung von Iodoniumkomplexen, Pentaazadienidoverbindungen mit Iod umgesetzt. Dies führte ebenfalls zur Bildung von Azoverbindungen, wie beispielsweise tolyl-N=N-tolyl. Since the discovery of the triazenido and pentaazadienido ligands a great variety of complexes containing these multidentate ligands have been synthesised and characterized. Studies have shown that these ligands have many coordination modes, including monodentate, bidentate, and bridging. This work is divided into two parts. The first part describes the synthesis of complexes formed with triazenido ligands. Usual methods for the synthesis of triazenido complexes were the reaction of a triazen with metal halides in presence of a base, as well as the reaction of metal triazenides with metal halides or a salt containing voluminous cations. The following complexes were obtained: [Na2(tolyl-N3-tolyl)2(THF)3]n, [Ru(tolyl-N3-tolyl)3], [RuCl(ClC6H4N3C6H4Cl)(p-Cymol)], [RuCl(tolyl-N3-tolyl)(Ph2PCH2C4H7O2)2], [(Ph3P)Rh(tolyl-N3-tolyl)2Cl], [PPh4]2[Ag4Cl4(ClC6H4N3C6H4Cl)2], [Et4N]2[Ag2(ClC6H4N3C6H4Cl)4]. Furthermore, attempts have been made to synthesise an iodonium complex through the reaction of silver triazenid with iodine. However, this reaction causes an oxidation of the triazenido ligand to the diazonium compound ClC6H4N=NC6H4Cl. The second part deals with the synthesis of pentaazadienido complexes. The complexes [RuCl(tolyl-N5-tolyl)(C6H6)], [Et4N][Ag2(tolyl-N5-tolyl)3], [PPh4][Ag2(tolyl-N5-tolyl)3], [(n-Bu)4N]3[Ag3I6] und [(n-Bu)4N][Ag2(tolyl-N5-tolyl)3] were synthesized. Analogue to the reaction with silver triazenid, an azo compound (tolyl-N=N-tolyl) was obtained through the reaction of pentaazadienido compound with iodine.