Synthesis and structure of 1,3-bis(hydroxysilyl)-2,4-dimethyl-2,4-diphenylcyclodisilazane

Trans-silylation reactions of (Me3Si)2NH with PhRSiCl2 (R = Me, Ph) gave HN(SiMePhCl)2 (1) or ClMePhSiNHSiPh2Cl (2). The treatment of 1,3-dichlorodisilazane (1 or 2) with an equimolar amount of n-BuLi led to the formation of 1,3-bis(chloro-silyl)-2,4-dimethyl-2,4-diphenylcyclodisilazane (ClSiMePh)2(NSiMePh)2 (3) or (ClSiPh2)2(NSiMePh)2 (4), which was allowed to hydrolyze to form 1,3-bis(hydroxysilyl)-2,4-dimethyl-2,4-diphenylcyclodisilazane (HOSiMePh)2(NSiMePh)2 (5) or (HOSiPh2)2(NSiMePh)2 (6), respectively. The cyclodisilazane monomers were characterized by elemental analysis, NMR and IR spectroscopy. Compound 3 was obtained as a 4:6 cis/trans mixture while 4 adopted trans-structure considering the hindrance of pendent groups. In addition, the molecular structures of trans-5 and trans-6 were determined by X-ray crystallographic analysis and discussed in detail.