th  - 1987 - 51st ENC Conference

MF27
MULTINUCLEAR SOLID-STATE NMR STUDIES OF DERIVATIZED SILICA GELS
Robert Zeigler, Greg Quinting, Charle~ E. Bronnimann
and Gary E. Maciel
Department of Chemistry
Colorado State University
Ft. Collins, CO 80523
Solid-state NMR has been demonstrated to be an extremely powerful
technique for probing the structure and dynamics of molecules bound to a
solid surface (1,2). IH, 15N, 29Si and 13C CP/MAS spectra will be pre-
sented for silica gels derivatized with APTS (aminopropyltriethoxysi-
lane). 13C, 15N, IH (CRAMPS) spectra provide evidence regarding the
nature of the interaction between the amine group of APTS-derivatized
silica gels and the silica gel surface.
13C and 29Si NMR techniques have been used to explore the conforma-
tions and dynamics of dimethyloctadecylchlorosilane(C18)-modified silica
gel. The effects of both C18 surface concentration and the presence of
solvents on the C18 chain dynamics have been explored using TCH and
dipolar dephasing experiments.
IH CRAMPS, 29Si and 13C NMR are being used to study the nature
of the silica surface and silica silylation. Several different species
of protons have been observed on the silica surface and a variety of
instrumental and chemical techniques are being used to characterize the
silica surface.
References
1. Solid State NMR Studies of Aminopropyltriethoxysilane Modified Silica;
G.S. Caravajal, D.E. Leyden, G.E. Maciel, p. 283 in Silanes, Surfaces,
and Interfaces Symposium, D.E. Leyden (ed.) Gordon and Breach Science
Publ. (1986).
2. NMR Studies of cl~-Derivatized Silica Systems; G.E. Maciel, R.C.
Zeigler, R.K. TaTt, p. 413 in Silanes, Surfaces, and Interfaces
Symposium, D.E. Leyden (ed.) Gordon and Breach Science Publ. (1986).