DEFT POLARIZATION TRANSFER IN SI-29-NMR INVESTIGATIONS OF ORGANICALLYMODIFIED ALKOXYSILANES

The DEFT heteronuclear polarization transfer pulse sequence was used t o unambiguously assign the high-resolution Si-29-NMR (nuclear magnetic resonance) for the hydrolyzed monomer species in trimethylmethoxysila ne, dimethyldimethoxysilane and methyltrimethoxysilane. The response o f the DEFT sequence as a function of the interpulse delay time tau and the variable pulse angle theta were analyzed for spin systems with mu ltiple heteronuclear J-couplings. These results allow the DEFT sequenc e to be optimized for sensitivity enhancement in addition to providing an editing method for Si-29-NMR of organically modified alkoxysilanes . (C) 1997 Elsevier Science B.V.