Auf der Grundlage von IR‐Untersuchungen im Bereich von 200–2 400 cm−1, von Elektronenspektren und Röntgenuntersuchungen werden die Strukturen von 3d‐Metall‐dicyanamiden M(N(CN)2)2 (M = Mn, Fe, Co, Ni, Cu, Zn) beschrieben. Die Verbindungen lassen sich zwei verschiedenen Strukturtypen zuordnen, in denen die Anionen entweder als dreizählige oder zweizählige Brückenliganden auftreten. Kobalt‐ und Mangan‐dicyanamid bilden Struktur‐Isomere mit pseudo‐oktaedrischer (α‐Formen) bzw. ‐tetraedrischer Mikrosymmetrie (β‐Formen). Der polymertetraedrische Verbindungstyp, dem auch Zinkdicyanamid zuzuordnen ist, scheint eine bisher nicht beschriebene Bindungsart verbrückender Dicyanamid‐Gruppen zu enthalten.

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Solute descriptors characterizing major interactions in solution are accessible based on quantitative structure-property relationships (QSPR). Parameters of such relationships should be additive for functional groups. Because added parameters of monools describing molecular interaction do not meet the experimentally found intermolecular interaction parameters of diols and triols, it is assumed that intramolecular hydrogen bonding is responsible for these deviations. In this paper the intramolecular interactions in several diols are illuminated by IR measurements. Particularly, the influence of intramolecular hydrogen bonding on the absorbances of the OH groups is subject of investigation. Two conclusions can be drawn from the results: The terminal OH groups, which underlie an OH–OH interaction, also change their absorbance intensity in comparison to the free OH band. Secondly, the intermolecular interaction potential is strongly affected by intramolecular hydrogen bonding. The first observation is tentatively quantified as well as the position of the equilibrium between intramolecularly bonded and free diols.

N,N-Dimethyl-N-N'-bis(trimethylsily1)urea (1) reacts with tertbutylchlorophenylphosphane (2) to form the monophosphino/ trimethylsilyl-substituted urea 3. Under more vigorous conditions the bisphosphino-substituted derivative 4 was also obtained. The reaction of 4 with the tetracarbonyl norbornadiene derivatives of Cr, Mo, and W furnished the unusual chelate complexes 5 -7 , in which the ligand 4 is coordinated to the metal through one of the two phosphorus atoms and the oxygen atom of the carbonyl group. The free ligand 4 and the isostructural complexes 5 and 6 were subjected to X-ray structure analyses. The approximate twofold symmetry of 4 is lost as a result of a major conformational change on complex formation. In contrast, 4 reacts with Fe2(C0)9 and with (COD)-PtClz (COD = 1,5-cyclooctadiene) to give the complexes 8 and 9. In both 8 and 9 the ligand 4 is coordinated by both phosphorus atoms. Reaction of 4 with sulfur and selenium led to -C7H8' I I .. M = Cr,Mo,W C7Hg = Norbornadien 5:M:Cr 6: M = M o 7 : M = W Chem. Ber. 124 (1991) 2705-2714