Edmund Friedrichs

Kristallstrukturen von isopropyl- und trimethylsilylmethylen-substituierten Chloro-hydroxo-tetraorganyl-distannoxanen

Abstract According to the results of the X-ray analysis, 1-chloro-3-hydroxo-tetra-isopropyl-distannoxane and 1-chloro-3-hydroxo-tetra-(trimethylsilylmethylene)-distannoxane are dimeric and show a “ladder-type” structure analogous to the 1,3-dichloro-and 1,3-dihydroxo derivatives. In contrast to the terminal chlorine atoms, the hydroxyl groups form strong asymmetric bridges between two tin atoms; the two compounds differ slightly in the asymmetry of these bridges.

Selective inclusion and orientation of chloroform in the molecular cavity of a 30-membered hexalactam host

X-Ray structural studies reveal that one chloroform guest molecule is embedded in molecular cavity formed by the synthetic large-ring host molecule (1) and is orientated in an unique Key–lock-type arrangement in such a way that the hydrogen atom of the chloroform projects into the centre of the macro-ring.

Spiroverknüpfte diorganylzinn-chalkogenide mit unterschiedlicher konformation

Abstract The non-planarity of the Sn 3 Y 3 rings in octaorganylspirobis(cyclotristan-nachalcogenans) leads to an interesting conformational isomerism of these compounds. X-ray structure analysis shows taht the t-butyl-substituted spirobis-(cyclotristannathian) has molecular symmetry D 2 , whereas the isopropyl-substituted compound adopts S 4 -conformation. Octaisopropylspirobis(cyclotristannaselenan) crystallizes isotypically to the sulphur compound. As 13 C and 119 Sn NMR spectra indicate, there is an equilibrium between the two forms in solution.