H-1 NOESY NMR ON ADSORBED MOLECULES

First H-1 NOESY NMR investigations on adsorbed molecules are presented . Experiments have been carried out on allyl alcohol adsorbed on NaX z eolite with a loading of approximately four molecules per supercage. B y application of magic angle spinning (MAS) on the sealed samples, all five magnetically inequivalent protons could be resolved spectroscopi cally. H-1 MAS NMR spectra in the temperature range from 260 to 420 K are reported. Cross peak and diagonal peak intensities of 2D NOESY spe ctra at room temperature for different mixing times have been measured . Subsequently the matrix of cross relaxation rates has been obtained by a single least mean square deviation fit to all 2D peak intensities . Errors in the determination of cross relaxation rates are discussed. Selected cross relaxation rates could be interpreted by isotropic reo rientation of the allyl group with a correlation time tau(c) = (6.1 +/ - 0.4) x 10(-9) s at a temperature of 300 K.