Some silatetraazaspiroalkanes with [4+4] octacoordinated silicon

Spirocyclic compounds containing an Si(N)(4) core have been prepared from 1 ,2-ethane- and 1,3 propanediamines bearing the electron-withdrawing p-tolue nesulfonyl groups at the four N atoms. According to the X-ray structure ana lysis of the compounds 8a and 13, the spirocyclic rings are almost perpendi cular to each other. In both cases a distorted dodecahedral arrangement of a [4 + 4] octacoordinate Si atom is found in which one O atom of each of th e four sulfonyl groups caps one of the planes defined by the Si(N), tetrahe dron. The O Si distances are 2.85-3.02 Angstrom and the two O Si O angles a re 145-159 degrees. According to the X-ray structure analysis of the monocy clic compound 16, one O atom of the p-toluenesulfonyl group caps the plane defined by O1-N2-C13 of the distorted S(N-2)(O)C tetrahedron.