The determination of the absolute parameters of nuclear magnetic resonance spectra of surface complexes of benzene with Co 2+ ions on Aerosil

Abstract

We propose a method for the determination of the number of active surface sites and of the absolute values of paramagnetic 1H-nmr-line shifts of coordinated molecules of surfaces containing paramagnetic ions. As an example the number of active Co 2+ ions in the complex formation of benzene molecules with Co 2+ ions on the Aerosil surface is determined. The paramagnetic 1H-nmr shift of a benzene molecule in the coordination sphere of a Co 2+ ion on Aerosil was found to be 150 ppm. Additional it was possible to detect the mechanism of exchange between coordinated and physically adsorbed molecules on the surface as a two particle substitution process.