C-13-Al-27 TRAPDOR and REDOR experiments for the detection of C-13-Al-27 dipolar interactions in solids

We report C-13-Al-27 double resonance experiments (REDOR and TRAPDOR) on se veral aluminum organic compounds with the aim of detecting C-13-Al-27 dipol ar couplings and distances in solids. The C-13 and Al-27 pulses are applied to the same probe channel because their resonance frequencies are in close proximity. The different possibilities of controlling the efficiency of th e TRAPDOR approach (by varying the Al-27 RF amplitude and the MAS frequency ) are investigated. The results indicate that TRAPDOR is superior to REDOR in resolving differences in C-13-Al-27 distances when choosing the proper e xperimental conditions. Where known, the crystal structure data are in qual itative agreement with the distance information extracted from our experime nts. The experiment should be very valuable in different fields of solid st ate chemistry, where the interaction of organic and inorganic sample fracti ons is of fundamental importance, (C) 1999 Academic Press.