Structure of 2,2,5,5,6,6,9,9-octamethyl-2,5,6,9-tetrasiladecane, a structural precursor of poly[(tetramethyldisilanediyl)ethylene]

In order to obtain information for suggesting the most likely molecular and crystal structure of poly[(tetramethyldisilanediyl)ethylene] (PTMDSE) an X‐ray study of the structural precursor 2,2,5,5,6,6,9,9‐octamethyl‐2,5,6,9‐tetrasiladecane (TSD) is carried out. The TDS molecule is centrosymmetric, the CSiCCSiSiCCSiC chain having an almost planar all‐trans conformation. In the crystal of TSD one can distinguish molecular layers parallel to the a b plane; the long axes of the TSD molecules form an angle of 24,4° with the layer plane; intermolecular contacts in layers are shorter, on the average, than interlayer contacts.