HIGH-RESOLUTION SOLID-STATE MAS C-13 AND H-1-NMR SPECTRA OF BENZENOID AROMATICS ADSORBED ON ALUMINA AND SILICA - SUCCESSFUL APPLICATIONS OF 1D-PULSE AND 2D-PULSE EXPERIMENTS FROM LIQUID-STATE NMR

Strong line-narrowing effects in solid-state, magic-angle-spinning (MAS) C-13 as well as H-1-NMR spectra of benzenoid aromatics adsorbed at alumina or silica surfaces indicate high mobility of the organic adsorbates. Even under modest spinning rates (1 kHz), dipolar couplings are sufficiently reduced to allow scalar C-13,H-1 couplings to be measured. Hetero- and homonuclear pulse sequences known from high-resolution NMR in liquids, like SEFT, J-RESOLVED, DEPT, COSY, and C-13,H-1 shift-correlation experiments are successfully applicable. C-13 spin-lattice relaxation times are as short as 0.5 s (CH) and 1.1 s (C(q)), and T1(H-1) values are in the order of 0.3 s.