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)Cl2}, R = 2,6-i-Pr2−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-Pr2−C6H3, 2a, and R = 2,6-Me2C6H3, 2b. X-ray crystal structures of 1a, 2a, and 2b have been carried out. The structure of 1a 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.