Two Different Cyclization Modes in the Formation of Silylhydrazines

Norbert W. Mitzel, Peter Bissinger, Jürgen Riede, Karl Heinz Dreihäupl, Hubert Schmidbaur

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


The reactions of 1,2-bis(bromosilyl)ethane and l,3-bis(bromosilyl)propane with anhydrous hydrazine lead to the two bicyclic silylhydrazines l,6-diaza-2,5,7,10-tetrasila[4.4.0]bicyclodecane (1) and bis(l-aza-2,6-disila-l-cyclohexyl) (2), respectively. For compound 1, a distillable liquid with mp 7 °C, the low-temperature crystal structure determination has shown a bicyclic configuration with the NN unit shared by two slightly twisted, chair-formed heterocycles. The NNSi2 units are virtually planar but not orthogonal relative to each other owing to conformational restraints. In crystals of compound 2, mp 57 °C, two six-membered rings each in a half-chair conformation are linked solely through the hydrazine NN bond. The two planar NNSi2 units are at right angles as expected for a nonforced tetrasilylhydrazine geometry. The NN bond is longer in 1 than in 2. Variable-temperature 1H 13C, 15N, and 29Si NMR spectra of both hydrazines have been measured, and the barrier of ring inversion of 1 has been determined.

Original languageEnglish
Pages (from-to)413-416
Number of pages4
Issue number2
StatePublished - 1993
Externally publishedYes


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