Formation and hydrogen bonding of a novel POSS-trisilanol.

The formation of t-butyl substituted polyhedral silsesquioxanes (POSS) starting from the corresponding silanetriol is reported. Several intermediates involved in this complex condensation process could be identified spectroscopically. In addition, the initial condensation intermediate t-Bu(2)Si(2)O(OH)(4), as well as t-Bu(6)Si(6)O(9) and t-Bu(7)Si(7)O(9)(OH)(3), could be characterized by X-ray crystallography. Owing to the high crystal quality it was possible to experimentally determine the geometric parameters of the unusual cyclic hydrogen bond network in a dimeric POSS trisilanol for the first time. Furthermore, we investigated the structural changes concomitant with dimer formation/dissociation of the t-butyl substituted POSS trisilanol and its methyl analogue.