Solid state NMR interaction parameters of oxygens linking titanium and silicon in crystalline cyclic titanodiphenylsiloxanes

O-17 static and magic angle spinning NMR spectra are reported from three: c rystalline cyclic titanodiphenylsiloxanes at magnetic fields of 5.6, 14.1, and 17.6 T. These compounds allow the NMR parameters characteristic of Ti-O -Si environments to be determined. It appears from these data that the quad rupole interaction (C-o) of such environments is in the range of 3-3.5 MHz and that Si-O-TiO3 sites are less shifted than Si-O-TiO5. The relatively la rge isotropic chemical range observed suggests that for structurally and at omically disordered titanosilicate-based materials the very highest applied magnetic field may not produce the best O-17 solid state NMR spectra. Ther e appears to he a correlation between the O-17 shift and T-O bondlength. (C ) 2001 Academic Press.