Effect of sterically hindered ligands on the solid-state structures of organosilanediols containing Si-N bonds

Organosilicon dichlorides containing Si-N bonds, RN(SiMe3){Si(Me)Cl-2}, R = 2,6-i-Pr-2-C6H3, 1a, and R = 2,6-Me2C6H3, 1b, serve as excellent precursors for the corresponding silanediols, RN(SiMe3){Si(Me)(OH)(2)}, R = 2,6-i-Pr-2-C6H3, 2a, and R = 2,6-Me2C6H3, 2b. X-ray crystal structures of 1a, 2a, and 2b have been carried out. The structure of la represents the first example of an organosilicon dichloride containing Si-N bonds. The N-bonded silanediol 2a, which contains the sterically encumbered isopropyl groups on the aromatic amino substituent on silicon, shows the formation of two different types of hexameric hydrogen-bonded clusters in the solid state. In contrast 2b consists of cyclic hydrogen-bonded dimers linked by further intermolecular hydrogen bonding to afford an overall polymeric structure with a crinkled ribbon like arrangement.